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Context: Individuals with chronic ankle instability (CAI) demonstrate reduced spinal reflex modulation and corticospinal excitability of the soleus, which may contribute to decreased balance performance. Objective: To determine the effects of a single session of balance training on Spinal-reflexive excitability modulation and corticospinal excitability in those with CAI. Design: Randomized controlled trials. Setting: Research laboratory. Participants: Thirty participants with CAI were randomly assigned to the balance training (BAL) or control (CON) group. Main Outcome Measures: Modulation of soleus spinal-reflexive excitability was measured by calculating relative change in normalized Hoffmann reflexes (ratio of the H-reflex to the M-wave) from prone to single-leg standing. Corticospinal excitability was assessed during single-leg stance using transcranial magnetic stimulation, outcomes of which included active motor threshold (AMT), motor evoked potential, and cortical silent period (CSP). Balance performance was measured with center of pressure velocity in anterior to posterior and medial to lateral directions. Separate 2x2 repeated-measures analyses of variance were employed to determine the effect of group (BAL and CON) and time (baseline and posttraining) on each dependent variable. Results: There were significant group by time interactions in the modulation of soleus spinal-reflexive excitability (F1.27 = 4.763, P=-04); CSP at 100% AMT (F F1.27 = 4.727, P = .04); and CSP at 120% AMT (F F1.27 16.057, f < .01). A large effect size suggests increased modulation of spinal-reflexive excitability (d = 0.81 [0.03 to 1.54]) of the soleus in BAL compared with CON at posttest, while CSP at 100% (d = 0.95 [0.17 to 1.70]) and 120% AMT (d = 1.10 [0.29 to 1.84]) was reduced in BAL when compared with CON at posttest. Conclusion: After a single session of balance training, individuals with CAI initiated increases in spinal reflex modulation and corticospinal excitability of the soleus. Thus, individuals with CAI who undergo balance training exhibit positive neural adaptations that are linked to improvements in balance performance. [ABSTRACT FROM AUTHOR]

Background and Purpose: This study was undertaken to examine vestibulo‐ocular reflex (VOR) characteristics in myotonic dystrophy type 1 (DM1) and type 2 (DM2) using video head impulse testing (vHIT). Methods: VOR gain, refixation saccade prevalence, first saccade amplitude, onset latency, peak velocity, and duration were compared in DM1, DM2, age‐matched normal controls, and patients with peripheral and central vestibulopathies. Results: Fifty percent of DM1 and 37.5% of DM2 patients demonstrated reduced VOR gain. Refixation saccade prevalence for horizontal canal (HC) and posterior canal (PC) was significantly higher in DM1 (101 ± 42%, 82 ± 47%) and DM2 (70 ± 45%, 61 ± 38%) compared to controls (40 ± 28% and 43 ± 33%, p < 0.05). The first saccade amplitudes and peak velocities were higher in HC and PC planes in DM1 and DM2 compared to controls (p < 0.05). HC slow phase eye velocity profiles in DM1 showed delayed peaks. The asymmetry ratio, which represents the percentage difference between the first and second halves of the slow phase eye velocity response, was therefore negative (−22.5 ± 17%, −2.3 ± 16%, and − 4.7 ± 8% in DM1, DM2, and controls). HC VOR gains were lower and gain asymmetry ratio was larger and negative in patients with DM1 with moderate to severe ptosis and a history of imbalance and falls compared to the remaining DM1 patients (p < 0.05). In peripheral vestibulopathies, saccade amplitude was larger, peak velocity was higher, and onset latency was shorter (p < 0.05) than in DM1. In central vestibulopathy (posterior circulation strokes), saccade peak velocity was higher, but amplitude and onset latency were not significantly different from DM1. Conclusions: VOR impairment is common in DM1 and DM2. In DM1, refixation saccade characteristics are closer to central than peripheral vestibulopathies. Delayed peaks in the vHIT eye velocity profile observed in patients with DM1 may reflect extraocular muscle weakness. VOR impairment and VOR asymmetry in DM1 are associated with imbalance and falls. [ABSTRACT FROM AUTHOR]

Reliable flood hazard mapping is crucial for enhancing flood preparedness, especially in poorly gauged and vulnerable areas. Yet, current flood models are either highly detailed and computationally intensive or oversimplified, failing to capture important flow dynamics. Here, we present the Rapid Estimation of FLood EXtent (REFLEX), a hydro‐geomorphological model for flood hazard mapping at multiple scales that improves upon the existing Height Above the Nearest Drainage model by constraining flood extent using physically‐coherent flood volumes. Input volume is distributed from channel to hillslope cells by using an iterative optimization based on the Manning's equation, bypassing the need for accurate rating curves. The model improves the accuracy of inundation extent in flat areas by accounting for backwater effects, and in coastal zones by extending the calculation boundaries beyond the direct watershed area. REFLEX was tested over five areas with different climatic conditions, including flash‐flood prone catchments in Italy and large floodplains in the Zambezi river basin. Results denote skillful representation of flooded areas in the Italian catchments, with critical success index (CSI) up to 0.62. In the African cases, REFLEX produced the best estimates of the flood extent and CSI comparable with two state of the art global inundation models. REFLEX is a competitive flood modelling tool for large scale and high resolution applications thanks to its limited input requirements and computing times two orders of magnitude shorter than equivalent hydraulic simulations. [ABSTRACT FROM AUTHOR]

Purpose: Sports training may lead to alterations in muscle reflex responses of the trained muscles. This study compared performance characteristics and the knee reflex (KR) and soleus Hoffmann (H-)reflex (SR) properties, as well as their potential associations in female volleyball players and non-athletes. Methods: Nine female amateur volleyball players (VP) in the middle of their competition season and nine age-matched women without athletic background, used as a control group (CG), participated in the study. KR and SR amplitude and latency, handgrip strength (HS), sit-and-reach, jumping performance [countermovement jump (CMJ) using one or both legs, and long jump (LJ)] were assessed. Results: VP performed better than CG in CMJ-both legs (27.99 cm vs 20.02 cm; p = 0.006), CMJ-non-dominant leg (13.40 cm vs 9.88 cm; p = 0.02), HS-dominant arm (33.67 kg vs 27.64 kg, p = 0.002) and HS-non-dominant arm (32.44 kg vs 24.64 kg; p = 0.001). There were no significant differences (p > 0.05) in the reflex properties between the groups. A positive correlation was found between SR latency and CMJ-both legs (VP: ρ = 0.7, p < 0.05, CG: ρ = 1, p = 0.01). Interestingly, only in the control group, there was also a positive correlation between KR and SR latencies (ρ = 0.96, p < 0.001) and a negative correlation between KR latency and amplitude (ρ = − 0.68, p < 0.05). Conclusions: Although volleyball players performed better in vertical (CMJ) jumps, the expected training-induced alterations in KR and SR reflex properties were not observed. This finding, combined with the correlations between SR latency and CMJ in both groups, suggests similar neuromuscular function in the trained and untrained subjects. [ABSTRACT FROM AUTHOR]

In quadrupeds, such as cats, cutaneous afferents from the forepaw dorsum signal external perturbations and send inputs to spinal circuits to co‐ordinate the activity in muscles of all four limbs. How these cutaneous reflex pathways from forelimb afferents are reorganized after an incomplete spinal cord injury is not clear. Using a staggered thoracic lateral hemisections paradigm, we investigated changes in intralimb and interlimb reflex pathways by electrically stimulating the left and right superficial radial nerves in seven adult cats and recording reflex responses in five forelimb and ten hindlimb muscles. After the first (right T5–T6) and second (left T10–T11) hemisections, forelimb–hindlimb co‐ordination was altered and weakened. After the second hemisection, cats required balance assistance to perform quadrupedal locomotion. Short‐, mid‐ and long‐latency homonymous and crossed reflex responses in forelimb muscles and their phase modulation remained largely unaffected after staggered hemisections. The occurrence of homolateral and diagonal mid‐ and long‐latency responses in hindlimb muscles evoked with left and right superficial radial nerve stimulation was significantly reduced at the first time point after the first hemisection, but partially recovered at the second time point with left superficial radial nerve stimulation. These responses were lost or reduced after the second hemisection. When present, all reflex responses, including homolateral and diagonal, maintained their phase‐dependent modulation. Therefore, our results show a considerable loss in cutaneous reflex transmission from cervical to lumbar levels after incomplete spinal cord injury, albeit with preservation of phase modulation, probably affecting functional responses to external perturbations. Key points: Cutaneous afferent inputs co‐ordinate muscle activity in the four limbs during locomotion when the forepaw dorsum contacts an obstacle.Thoracic spinal cord injury disrupts communication between spinal locomotor centres located at cervical and lumbar levels, impairing balance and limb co‐ordination.We investigated cutaneous reflexes from forelimb afferents during quadrupedal locomotion by electrically stimulating the superficial radial nerve bilaterally, before and after staggered lateral thoracic hemisections in cats.We showed a loss/reduction of mid‐ and long‐latency homolateral and diagonal reflex responses in hindlimb muscles early after the first hemisection that partially recovered with left superficial radial nerve stimulation, before being reduced after the second hemisection.Targeting cutaneous reflex pathways from forelimb afferents projecting to the four limbs could help develop therapeutic approaches aimed at restoring transmission in ascending and descending spinal pathways. [ABSTRACT FROM AUTHOR]

Background: Outcome measures in clinical practice assist in establishing progress for effective quality of care. Physiotherapists in the intensive care unit (ICU) promote lung function and facilitate early mobilization to prevent ICU-related complications. Objectives: To determine the physical functional outcomes in critically ill patients in the trauma and medical critical care units at three hospitals in the Tshwane District. Method: This was a quantitative prospective observational cohort study. Adult patients admitted in the trauma, medical ICU, and high care (HC) units were recruited. Ethical clearance was obtained from the [Masked for blind review], the National Department of Health Research (NHRD), and the Chief Executive Officers (CEOs) of the hospitals. Written consent was obtained from the recruited patients. Assessments were done on Mondays, Wednesdays, and Fridays using the Chelsea Critical Care Physical Assessment (CPAx) Tool until discharge from the units. Data were analyzed using SPSS version 28. Results: Functional outcomes that improved quicker were respiratory function, cough reflex, rolling in the bed, and grip strength. An increase in CPAx scores correlated with improvement in the Glasgow coma scale (GCS) in both groups. Median and inter-quartile CPAx scores in the medical ICU for the initial assessments were 3(2–8) with an increase to 8(3.75–28.25) in the final assessment (p = 0.003). The median and interquartile CPAxs scores for initial assessments in the trauma ICU were 2(1–11.75) and 5(3.25–14) for the final assessments, with a p-value of 0.005 which showed statistical significance. Conclusion: CPAx mean scores in the trauma ICU were higher than in the medical ICU. There were significant positive changes in the scoring of both populations but this was slightly better in the trauma ICU. Using the CPAx tool in a HC setting seemed feasible and patients showed higher scores compared to both trauma and medical ICU. Clinical implications : The CPAX tool assists in the development of rehabilitation goals in the ICU and HC by physiotherapists. The tool can be adapted in the medical and trauma critical care units to assess functional outcomes. Trial registration: Pan African Clinical Trials Registry, PACTR202305860988637, Registered 7 May 2023-Retrospectively registered, https://pactr.samrc.ac.za/TrialDisplay.aspx?TrialID=25542. [ABSTRACT FROM AUTHOR]

Study objective was to evaluate whether the application of a lip twitch could be proposed as conditioning stimulus in the context of a novel Conditioned Pain Modulation (CPM) assessment paradigm for use in horses. The study was a prospective, experimental, randomized trial. Twelve healthy horses were evaluated in two experimental sessions. The lip twitch was used as the conditioning stimulus in both sessions; electrical stimulation was used as the test stimulus in one session, while mechanical and thermal stimulations were used in the other. Differences between thresholds recorded before and during twitching (Δ) as well as their percent (%) change were computed for each stimulation modality as a measure of CPM. Heart rate and respiratory rate were recorded throughout the experiments to monitor physiological reactions, while the general level of stress and aversiveness toward twitching were scored using ad hoc behavioural scales. Based on these scores, interruption criteria were defined. Ten and seven horses completed the electrical and mechanical/thermal experimental sessions respectively. For electrical stimulation, median (IQR) Δ was −2.8 (−3.9, −1.1) mA and% change 87.9 (65.7–118.2)%; for mechanical stimulation, Δ was −18.2 (−6.4, −21.4) N and% change 343.5 (140, 365.3)%; for thermal stimulation, Δ was −3.1 (−9.2, −2.1)°C, while% change was not calculated. Heart rate and respiratory rates varied significantly over time, with higher values recorded during twitching. Median stress and aversion scores did not differ between the two sessions. As lip twitching consistently affected thresholds to all stimulation modalities, it can be proposed as effective conditioning method for CPM assessment in horses. The exclusion of subjects due to severe aversion shows that this paradigm cannot be indistinctively applied to all horses and that stringent interruption criteria are necessary to guarantee adequate welfare during testing. [ABSTRACT FROM AUTHOR]

Background: In the neurological examination, it is crucial to identify the possible location of the lesion in order to determine the appropriate treatment process. In aggressive animals, chemical restraint may be necessary due to their non‐cooperative behaviour. However, sedatives may distort the results of examinations. Therefore, a drug should be found that has minimal impact on the examination results. Objectives: To investigate the effects of acepromazine, xylazine, and propofol on spinal reflexes in healthy dogs. Methods: In a randomized, blinded study, ten native adult mixed‐breed dogs were participated in three groups with a 1‐week washout period between each group. Before performing each step, the spinal reflexes were evaluated. Then, in the first group, acepromazine (0.05 mg/kg, IM), in the second group, xylazine (1 mg/kg, IM), and in the third group, propofol (3 mg/kg, IV for initial bolus and 0.1 mg/kg/min for maintenance) were injected for sedation. The spinal reflexes were reevaluated at maximum sedation and at 15, 30, and 45 min thereafter. Results: Acepromazine increased the patellar reflex and decreased the panniculus reflex. Xylazine increased the cranial tibial reflex and decreased the panniculus reflex, while propofol decreased the withdrawal, and extensor carpi radialis reflexes, and suppressed the palpebral and gag reflexes. Conclusions: The drugs used in the present study did not have a significant impact on the most important reflexes evaluated in neurological examinations. Among the drugs, acepromazine has the least effects compared to other drugs, making it a suitable choice for sedation. [ABSTRACT FROM AUTHOR]

The muscle metaboreflex effect on pulmonary ventilation (V̇E) regulation is more apparent during rhythmic exercise than rest, possibly because this reflex interacts with other mechanisms regulating V̇E during voluntary contractions, such as central command. Therefore, we tested whether one part of central command, the descending component of motor execution (i.e., descending motor drive), and the muscle metaboreflex interact synergistically to regulate V̇E. Thirteen healthy adults (9 men) completed four experiments in random order under isocapnia. The muscle metaboreflex was activated by rhythmic handgrip exercise at 60% maximal voluntary contraction (MVC) force with the dominant hand. Then, the muscle metaboreflex remained active during a 4-min recovery period via postexercise circulatory occlusion (PECO), or it was inactivated, maintaining free blood flow to the dominant upper limb. During the last 2 min of the handgrip exercise recovery, participants either performed rhythmic voluntary plantar flexion with the dominant leg at 30% MVC torque to generate descending motor drive or the dominant leg's calf muscles were involuntarily activated by electrical stimulation at a similar torque level (i.e., without descending motor drive). V̇E increased to a similar level during handgrip exercise in all conditions (≈22 L/min, P = 0.364). PECO maintained V̇E elevated above recovery with free blood flow (≈17 L/min vs. ≈13 L/min, P = 0.009). However, voluntary and involuntary plantar flexion with or without PECO evoked similar V̇E responses (Δ ≈ 4 L/min, P = 0.311). Therefore, an interaction between descending motor drive and muscle metaboreflex is not ubiquitous for V̇E regulation during rhythmic exercise. NEW & NOTEWORTHY: Voluntary (i.e., with descending motor drive) and involuntary (i.e., no descending motor drive) plantar flexion elicited similar ventilatory responses when postexercise circulatory occlusion was or was not used in an upper limb. These results indicate that the descending motor drive component of the central command and the muscle metaboreflex do not interact to regulate pulmonary ventilation during rhythmic exercise, which suggests that a supposed interaction between central command-muscle metaboreflex is more complex than previously thought. [ABSTRACT FROM AUTHOR]

Purpose: A relevant aspect of listening is the effort required during speech processing, which can be assessed by pupillometry. Here, we assessed the pupil dilation response of normal-hearing (NH) and hard of hearing (HH) individuals during listening to clear sentences and masked or degraded sentences. We combined this assessment with functional magnetic resonance imaging (fMRI) to investigate the neural correlates of the pupil dilation response. Method: Seventeen NH participants (Mage = 46 years) were compared to 17 HH participants (Mage = 45 years) who were individually matched in age and educational level. Participants repeated sentences that were presented clearly, that were distorted, or that were masked. The sentence intelligibility level of masked and distorted sentences was 50% correct. Silent baseline trials were presented as well. Performance measures, pupil dilation responses, and fMRI data were acquired. Results: HH individuals had overall poorer speech reception than the NH participants, but not for noise-vocoded speech. In addition, an interaction effect was observed with smaller pupil dilation responses in HH than in NH listeners for the degraded speech conditions. Hearing impairment was associated with higher activation across conditions in the left superior temporal gyrus, as compared to the silent baseline. However, the region of interest analysis indicated lower activation during degraded speech relative to clear speech in bilateral frontal regions and the insular cortex, for HH compared to NH listeners. Hearing impairment was also associated with a weaker relation between the pupil response and activation in the right inferior frontal gyrus. Overall, degraded speech evoked higher frontal activation than clear speech. Conclusion: Brain areas associated with attentional and cognitive-control processes may be increasingly recruited when speech is degraded and are related to the pupil dilation response, but this relationship is weaker in HH listeners. [ABSTRACT FROM AUTHOR]

Although many studies have shown a long‐term negative impact of early life adversity (ELA) in rodents, literature regarding its effects on maturational milestones in rats is scarce. Available evidence suggests that ELA interferes with normal growth and development in rodents and that effects may be sex‐dependent even at an early age. In accordance, we hypothesized that early life scarcity‐adversity would impair physical and reflex development in male and female rats. To test this, we used an early life resource scarcity paradigm based on reducing home cage bedding during postnatal days (PND) 2–9 and assessed physical landmarks by measuring weight gain, incisor presence, fur development, and eye opening. We also evaluated the impact of early life scarcity‐adversity on developmental reflexes by measuring surface righting and grasp reflexes, negative geotaxis, cliff avoidance, bar holding, and auditory startle. Early life scarcity‐adversity resulted in earlier complete lower incisor presence in males (PND 6), impaired surface righting (PND 6) and grasp reflexes (PND 8) in both sexes, and impaired cliff avoidance responses in females (PND 12). These results extend previous research examining the effects of ELA on developing male and female rodents by showing that it negatively impacts a subset of physical landmarks and developmental reflexes in a sex‐dependent manner. [ABSTRACT FROM AUTHOR]

A given dose of hypoxia causes a greater increase in pulmonary ventilation during physical exercise than during rest, representing an exercise‐induced potentiation of the acute hypoxic ventilatory response (HVR). This phenomenon occurs independently from hypoxic blood entering the contracting skeletal muscle circulation or metabolic byproducts leaving skeletal muscles, supporting the contention that neural mechanisms per se can mediate the HVR when humoral mechanisms are not at play. However, multiple neural mechanisms might be interacting intricately. First, we discuss the neural mechanisms involved in the ventilatory response to hypoxic exercise and their potential interactions. Current evidence does not support an interaction between the carotid chemoreflex and central command. In contrast, findings from some studies support synergistic interactions between the carotid chemoreflex and the muscle mechano‐ and metaboreflexes. Second, we propose hypotheses about potential mechanisms underlying neural interactions, including spatial and temporal summation of afferent signals into the medulla, short‐term potentiation and sympathetically induced activation of the carotid chemoreceptors. Lastly, we ponder how exercise‐induced potentiation of the HVR results in hyperventilation‐induced hypocapnia, which influences cerebral blood flow regulation, with multifaceted potential consequences, including deleterious (increased central fatigue and impaired cognitive performance), inert (unchanged exercise) and beneficial effects (protection against excessive cerebral perfusion). What is the topic of this review?What neural mechanisms are involved in the ventilatory response to hypoxic exercise and do they interact? What are the mechanisms underlying neural interactions during hypoxic exercise?What advances does it highlight?Current evidence does not support an interaction between the carotid chemoreflex and central command. In contrast, findings from some studies support synergistic interactions between the carotid chemoreflex and the muscle mechano‐ and metaboreflexes. Medullary signal summation, short‐term potentiation and sympathetic carotid chemoreceptor activation probably contribute to potentiation of the hypoxic ventilatory response during exercise, impacting cerebral blood flow and oxygenation via hyperventilation‐induced hypocapnia. [ABSTRACT FROM AUTHOR]

An overactive orexin (OX) system is associated with neurogenic hypertension and an exaggerated chemoreflex in spontaneously hypertensive rats (SHRs). However, the chronology and mechanism of this association is unclear. We hypothesized that increased postnatal neurogenesis of OX neurons in SHRs precedes and contributes to the aberrant increase in mean arterial blood pressure (MAP) and the exaggerated response to hypercapnia during postnatal development. Using immunohistochemical methods and bromodeoxyuridine, we mapped the timeline of orexin neuron neurogenesis and maturation during early postnatal development. We then used whole-body plethysmography with EEG and EMG to map the development of mean arterial pressure (MAP) and state regulation. Finally, we used OX-targeted saporin toxin to determine the effects of eliminating excess OX neurons on the elevated MAP and exaggerated chemoreflex in adult SHRs. We found that both SHRs and Wistar-Kyoto (WKY) rats experienced postnatal increases in OX neurons. However, SHRs experienced a greater increase than WKY rats before P15, which led to significantly more OX neurons in SHRs than age-matched WKY controls by P15-16 (3,720 ± 780 vs. 2,406 ± 363, p = 0.005). We found that neurogenesis, as evidenced by BrdU staining in OX-positive neurons, was the primary contributor to the excess OX neurons in SHRs during early postnatal development. While SHRs develop more OX neurons by P15-16, SHRs and normotensive WKY control rats have similar MAP during postnatal development until P25 in wakefulness (81.6 ± 6.6 vs. 67.5 ± 6.8 mmHg, p = 0.006) and sleep (79.3 ± 6.1 vs. 66.6 ± 6.5, p = 0.009), about 10 days after the surge of OX neurons. By selectively eliminating excess (~30%) OX neurons in SHRs, we saw a significantly lowered MAP and hypercapnic ventilatory chemoreflex compared to non-lesioned SHRs at P40. Additionally, we found unique signatures in state indicative of the attention defecit phenotype commonly associated with this model. We suggest that the postnatal increase of OX neurons, primarily attributed to exaggerated postnatal OX neurogenesis, may be necessary for the development of higher MAP and exaggerated chemoreflex in SHRs, and modulation of the overactive OX system may have a potential therapeutic effect during the pre-hypertensive period. [ABSTRACT FROM AUTHOR]

Background: Chronic pain from peripheral neuromas is difficult to manage and often requires surgical excision, though intraoperative identification of neuromas can be challenging due to anatomical ambiguity. Mechanical manipulation of the neuroma during surgery can elicit a characteristic "startle sign", which can help guide surgical management. However, it is unknown how anesthetic management affects detection of the startle sign. Methods: We performed a retrospective cohort study of 73 neuroma excision surgeries performed recently at Massachusetts General Hospital. Physiological changes in the anesthetic record were analyzed to identify associations with a startle sign event. Anesthesia type and doses of pharmacological agents were analyzed between startle sign and no-startle sign groups. Results: Of the 64 neuroma resection surgeries included, 13 had a startle sign. Combined intravenous and inhalation anesthesia (CIVIA) was more frequently used in the startle sign group vs. no-startle sign group (54% vs. 8%), while regional blockade with monitored anesthetic care was not associated with the startle sign group (12% vs. 0%), p = 0.001 for anesthesia type. Other factors, such as neuromuscular blocking agents, ketamine infusion, remifentanil infusion, and intravenous morphine equivalents showed no differences between groups. Conclusions: Here, we identified hypothesis-generating descriptive differences in anesthetic management associated with the detection of the neuroma startle sign during neuroma excision surgery, suggesting ways to deliver anesthesia facilitating detection of this phenomenon. Prospective trials are needed to further validate the hypotheses generated. [ABSTRACT FROM AUTHOR]

Competitive swimmers complete 50‐m front crawl swimming without breathing or with a limited number of breaths. Breath holding during exercise can trigger diving reflex including bradycardia and diminished active muscle blood flow, whereas oxygen supply to vital organ such as brain is maintained. We hypothesized that swimmers achieving faster time in 50‐m front crawl with limited number of breaths demonstrate a blunted diving reflex of cardiac and active muscle blood flow responses with elevated cerebral perfusion to counteract peripheral and central fatigues. Twenty‐eight competitive swimmers (12 females) underwent a 50‐m front crawl swimming time trial with minimum respiratory interruptions, following which they were categorized into two groups: Fast (n = 13) and Slow (n = 15). Additionally, they performed knee extension exercises with maximal voluntary breath‐ holding, wherein leg blood flow (Doppler ultrasound), cardiac output (Modelflow), heart rate (electrocardiogram), and middle cerebral artery mean blood velocity (transcranial Doppler ultrasound) were evaluated. The pattern of leg blood flow response differed between the two groups (p = 0.031) with the Fast group experiencing a delayed onset of reductions in leg blood flow (p = 0.035). The onset of bradycardia was also delayed in the Fast group (p = 0.014), with this group demonstrating a higher value of the lowest heart rate (between‐trial difference in average: 15.9 [3.73, 28.2] beats/min) and cardiac output (between‐trial difference in median: 2.84 L/min) (both, p ≤ 0.013). Middle cerebral artery mean blood velocity was similar between the groups (all p ≥ 0.112). We show that swimmers with superior performance in 50‐m front crawl swim with limited breaths display a diminished diving reflex. [ABSTRACT FROM AUTHOR]

Effective regulation of emotions is essential in coping with everyday stressors. Although cognitive reappraisal and acceptance are both commonly employed to downregulate negative emotions, they differ in many aspects. Their effectiveness in real‐life situations can also be influenced by prior stress or a person's trait preferences for certain emotion regulation (ER) strategies. In the present study, we compared the effectiveness of both ER strategies in a laboratory setting, while focussing on the effect of stress and trait moderators. Ninety‐eight healthy participants aged 18–40 were randomly divided into three groups with instructions to use reappraisal, acceptance, or nothing while viewing distressing pictures from the IAPS database. Half of the participants in each group underwent a laboratory stressor (socially evaluated cold pressor test) 20–30 min before the ER task. The effectiveness of ER was measured subjectively on the visual analog scale, and by measuring heart rate, skin conductance, and pupil responses. The data show that cognitive reappraisal lowered subjectively experienced negative emotion, while acceptance did not. These group differences were however not supported by psychophysiological indicators. Secondly, although the laboratory stressor elicited cortisol stress responses in our participants, we did not find any effect on ER. Furthermore, the data has not supported the moderation effect by trait reappraisal and acceptance. The present findings show that deliberate usage of ER strategies when viewing emotionally charged pictures leads to a decrease in experienced emotion. On the other hand, the effects of stress and trait moderators were not supported, therefore they may be smaller and more variable than expected. [ABSTRACT FROM AUTHOR]

Oral contraceptive (OC) use can increase resting blood pressure (BP) in females as well as contribute to greater activation of group III/IV afferents during upper body exercise. It is unknown, however, whether an exaggerated BP response occurs during lower limb exercise in OC users. We sought to elucidate the group III/IV afferent activity-mediated BP and heart rate responses while performing lower extremity tasks during early and late follicular phases in young, healthy females. Females not taking OCs (NOC: n = 8; age: 25 ± 4 yr) and those taking OCs (OC: n = 10; age: 23 ± 2 yr) completed a continuous knee extension/flexion passive stretch (mechanoreflex) and cycling exercise with subsystolic cuff occlusion (exercise pressor reflex), which was followed by a 2-min postexercise circulatory occlusion (PECO) (metaboreflex). Data collection occurred on two occasions: once during the early follicular phase (days 1–4) and once during the late follicular phase (days 10–14) of their menstrual cycle (NOC) or during the placebo and active pill phases (OC). Resting mean arterial BP and heart rate were not different between phases in NOC and OC participants (P > 0.05). Hemodynamic responses to metaboreflex, mechanoreflex, and collective exercise pressor reflex activation were not different between phases in both groups (P > 0.05). In conclusion, although OCs are known to increase BP at rest, our findings indicate that neither endogenous nor exogenous (OC) sex hormones modulate BP during large, lower limb muscle exercise with or without group III/IV afferent activation in young, healthy females. NEW & NOTEWORTHY: Sex differences in the cardiovascular response to exercise have been demonstrated and may be dependent on sex hormone levels. Furthermore, oral contraceptives (OCs) have been shown to exaggerate the blood pressure response to upper extremity exercise. The results of this study indicate that neither endogenous nor exogenous (OC) sex hormones modulate BP during lower extremity dynamic exercise or with group III/IV afferent activation in young, healthy females. [ABSTRACT FROM AUTHOR]

There is evidence that astrocytes modulate synaptic transmission in the nucleus tractus solitarius (NTS) interacting with glutamatergic and purinergic mechanisms. Here, using in situ working heart-brainstem preparations, we evaluated the involvement of astrocyte and glutamatergic/purinergic neurotransmission in the processing of autonomic and respiratory pathways in the NTS of control and rats exposed to sustained hypoxia (SH). Baseline autonomic and respiratory activities and the responses to chemoreflex activation (KCN) were evaluated before and after microinjections of fluorocitrate (FCt, an astrocyte metabolic inhibitor), kynurenic acid, and pyridoxalphosphate-6-azophenyl-2′,4′-disulfonate (PPADS) (nonselective antagonists of glutamatergic and purinergic receptors) into the rostral aspect of the caudal commissural NTS. FCt had no effects on the baseline parameters evaluated but reduced the bradycardic response to chemoreflex activation in SH rats. FCt combined with kynurenic acid and PPADS in control rats reduced the baseline duration of expiration, which was attenuated after SH. FCt produced a large increase in PN frequency discharge in control rats, which was reduced after SH, indicating a reduction in the astrocyte modulation after SH. The data show that 1) the bradycardic component of the peripheral chemoreflex is reduced in SH rats after astrocytes inhibition, 2) the inhibition of astrocytes in the presence of double antagonists in the NTS affects the modulation of baseline duration of expiration in control but not in SH rats, and 3) the autonomic and respiratory responses to chemoreflex activation are mediated by glutamatergic and purinergic receptors in the rostral aspect of the caudal commissural NTS. NEW & NOTEWORTHY: Our findings indicate that the neurotransmission of autonomic and respiratory components of the peripheral chemoreflex in the nucleus tractus solitarius (NTS) is mediated by glutamatergic and purinergic mechanisms and reveal a selective involvement of NTS astrocytes in controlling the chemoreflex parasympathetic response in rats exposed to sustained hypoxia (SH) and the baseline duration of expiration mainly in control rats, indicating a selective role for astrocytes modulation in the NTS of control and SH rats. [ABSTRACT FROM AUTHOR]

Background: Prokinetic agents are effective in increasing gastrointestinal (GI) contractility and alleviating constipation, often caused by slow intestinal motility. Lubiprostone (LUB), known for activating CLC-2 chloride channels, increases the chloride ion concentration in the GI tract, supporting water retention and stool movement. Despite its therapeutic efficacy, the exact mechanisms underlying its pharmacological action are poorly understood. Here, we investigated whether LUB activates the canonical transient receptor potential cation channel type 4 (TRPC4) through stimulation with E-type prostaglandin receptor (EP) type 3. Methods: Using isotonic tension recordings on mouse colon strips, we examined LUB-induced contractility in both proximal and distal colon segments. Quantitative real-time polymerase chain reaction (qRT-PCR) was conducted to determine mRNA levels of EP1-4 receptor subtypes in distal colonic muscular strips and isolated myocytes. The effects of a TRPC4 blocker and EP3 antagonist on LUB-stimulated contractions were also evaluated. Results: LUB showed significant contraction in the distal segment compared to the proximal segment. EP3 receptor mRNA levels were highly expressed in the distal colon tissue, which correlated with the observed enhanced contraction. Furthermore, LUB-induced spontaneous contractions in distal colon muscles were reduced by a TRPC4 blocker or EP3 antagonist, indicating that LUB-stimulated EP3 receptor activation may lead to TRPC4 activation and increased intracellular calcium in colonic smooth muscle. Conclusions: These findings suggest that LUB improves mass movement through indirect activation of the TRPC4 channel in the distal colon. The segment-specific action of prokinetic agents like LUB provides compelling evidence for a personalized approach to symptom management, supporting the defecation reflex. [ABSTRACT FROM AUTHOR]

Local vibration (LV) mainly stimulates primary afferents (Ia) and can induce a tonic vibration reflex (TVR) and an illusion of movement. This study aimed to evaluate the effect of these two phenomena on maximal voluntary isometric contraction (MVIC) capacity. LV (80 Hz) was applied to the wrist flexor muscles in two randomized experiments for 6 min. LV conditions were adjusted to promote either TVR (visual focus on the vibrated wrist) or ILLUSION [hand hidden, visual focus on electromyographic activity of the flexor carpi radialis muscle (FCR)]. Mechanical and electromyographic (EMG) responses of the FCR and extensor carpi radialis muscles were recorded during MVIC in flexion and extension and during electrically evoked contractions at supramaximal intensity. Measurements were performed before (10 min and just before) and after (0 and 30 min) LV protocol. An increase in FCR EMG was observed during LV in the TVR condition (+340%) compared with the illusion condition (P = 0.003). In contrast, the movement illusion was greater in the ILLUSION condition (assessed through subjective scales) (P = 0.004). MVIC was reduced in flexion only after the TVR condition (≈ − 7 % , all P < 0.034). Moreover, the decrease in force was correlated with the amount of TVR recorded on the FCR muscle (r = −0.64, P = 0.005). Although potentiated doublets of each muscle did not evolve differently between conditions, a decrease was observed between the first and the last measure. In conclusion, when conducting research to assess maximal strength, it is necessary to have better control and reporting of the phenomena induced during LV. NEW & NOTEWORTHY: The maximal force production of the vibrated muscle is reduced after 6 min of LV only in TVR condition. Furthermore, the amount of TVR is negatively correlated with this force decrease. When measuring the effects of LV on maximal force production, it is important to control and report any phenomena induced during vibration, such as TVR or movement illusion, which can be achieved by recording EMG activity of vibrated muscle and quantifying illusion. [ABSTRACT FROM AUTHOR]

In many languages, a subject/non-subject Ā-extraction asymmetry can be observed: While non-subject extraction is unproblematic, long extraction of the subject requires repair strategies. This phenomenon is known as the that-trace effect. Two broad types of approaches to this effect have been proposed in the literature: (a) structural accounts that prohibit subject extraction in the syntax; (b) surface-oriented PF accounts according to which nothing blocks long subject movement in the syntax, but a surface filter prohibits the output string where a trace follows the complementizer. In this paper, we argue for a syntactic cause of the effect in Igbo (Benue-Congo, Nigeria). The empirical evidence centers around the distribution of resumptive pronouns in the language. We show that Igbo has all the ingredients required for a PF approach to the that-trace effect (viz., long Ā-movement and trace spell-out); nevertheless, it does not apply them to enable long subject extraction but rather resorts to prolepsis (among other strategies). Further evidence against a PF account comes from the impossibility of short subject extraction. Finally, we provide evidence from subextraction from subjects for an antilocality component underlying the subject extraction restriction in Igbo. [ABSTRACT FROM AUTHOR]

Concussion assessment in adapted and parasport athletes has continued to evolve with growing considerations in parasports, but little is known about vestibular/ocular performance assessment in this sample. To examine baseline performance on the Vestibular/Ocular Motor Screening (VOMS) in collegiate adapted athletes. A secondary objective was to investigate the role of sex, history of concussion, and functional classification on baseline measures. Cross-sectional study. University adapted athletics facility. Fifty-four collegiate adapted athletes (age = 21.19 ± 2.6 years) from multiple institutions' adapted athletics programs across the United States. Adapted athletes completed a baseline VOMS assessment while at the host university for in-season competition and tournaments. Independent variables were sex, history of concussion and functional classification (1.0–4.5 at 0.5 intervals). Vestibular/Ocular Motor Screening performance consisted of pretest symptoms (headache, dizziness, nausea, and fogginess) and postitem (eg, smooth pursuits, saccades) symptom provocation or change from pretest scores. A proportion of 50.9% reported zero symptom provocation on the VOMS, with 72% having no pretest symptoms. No sex differences were noted on the VOMS (P >.05); however, adapted athletes with a history of concussion reported greater VOMS provocation on horizontal saccades (P =.008) than those with no history. Higher functional classifications (2.0–4.5) reported greater provocation on horizontal saccades (P =.010), horizontal and vertical (P =.043 and.048) vestibular/ocular reflex, and vestibular/ocular reflex cancellation (P =.036) than 1.0–1.5 athletes. Our findings provide context for baseline VOMS performance in collegiate adapted athletes and identifying modifiers at baseline. Special consideration is warranted on vestibular and oculomotor assessment in adapted and parasport athletes with a history of concussion and higher functional classifications. [ABSTRACT FROM AUTHOR]

Background: Local anaesthesia in dental procedures is generally safe, although the occurrence of transient bradycardia (TB) has occasionally been reported. TB is often associated with two reflexes, the trigeminal cardiac reflex (TCR) and the vasovagal reflex (VVR) and is characterised by a rapid decrease in heart rate (HR) and blood pressure (BP). The prevalence of TCR is considered low, and its predictors have not been thoroughly investigated, although an association with the gag reflex has been suggested in recent years. Methods: This prospective study assessed TB occurrence during local anaesthesia and its potential associated factors. A comprehensive questionnaire was used to categorise discomforts during dental treatment, and various anxiety scales were used to measure patients' anxiety levels. We investigated HR variability during local anaesthesia administration under sedation and the association between the incidence of TB and gag reflex. Subsequently, logistic regression analysis was performed to assess factors associated with TB occurrence. Results: The prospective analysis included 188 patients of 234 initial patients. The analysis revealed a high TB incidence rate of 41% during local anaesthesia administration under sedation. No severe hypotensive events occurred, indicating a relatively benign nature of TB during local anaesthesia. TB occurrence was significantly higher in the group of patients with the gag reflex. Further analysis revealed that both gag reflex and trait anxiety were significantly associated with TB occurrence, whereas dental phobia did not directly correlate with TB. Conclusion: This study highlights the prominent occurrence of TB during local anaesthesia in dental treatment, which is primarily attributed to TCR activation. The identification of gag reflex and trait anxiety as independent factors associated with TB development may pave the way for TB prevention measures. Further research is required to clarify the mechanisms of TCR and perform safer dental procedures under sedation. Future studies should also aim to elucidate the precise mechanisms underlying TB during local anaesthesia through direct measurements of neural activity. A better understanding of TB in dentistry is crucial for improving patient safety and optimising dental practice protocols. [ABSTRACT FROM AUTHOR]

Recognition memory, the ability to recognise previously encountered information, correlates with pupil diameter changes during the recognition period. This physiological response, known as the pupil old/new effect, generally reflects the variation in pupil dilation when encountering previously studied (old) stimuli compared to new stimuli. To develop a more precise understanding of the pupil old/new effect, we conducted a meta-analysis of 17 eye-tracking experiments (across 12 articles spanning from 2008 to 2023) involving 560 healthy adults with a mean age of 22.31 years. Analysis of publication bias showed a rather low risk of bias in the selected articles. The main meta-analysis revealed a significant and large pooled pupil old/new effect (Cohen's dz = 0.73, 95% CI [0.50, 0.95]). Further analysis of moderators showed that the number of participants included in the experiments and the criteria for selecting trials (only correct trials vs. all trials) had a significant impact on the meta-analytic results. In general, the analyses revealed a robust pupil old/new effect across all selected articles. This finding underscores its potential utility as a marker of recognition memory across different stimuli type, and various experimental designs. [ABSTRACT FROM AUTHOR]

This review delves into the complexities of insect behaviour, particularly the interplay between innate and learned behaviours and the factors influencing learning in organisms. Innate behaviours, such as reflex actions and fixed action patterns are genetically hard-wired and manifest without prior experience. In contrast, learned behaviours, acquired through experience, include habituation, imprinting, classical conditioning, and operant conditioning. The propensity to learn is influenced by environmental variability, with organisms benefiting from learning in environments with predictable patterns. The study explores the specialization versus generalization in behaviour, highlighting how coevolution and mutualism drive specialization in certain organisms, but also how this can lead to co-extinction due to interdependence. Conversely, generalists may exhibit better learning abilities in environments with greater variability. The role of lifespan, body size and the size of mushroom bodies in the brain, which store sensory memories, are also considered, suggesting that larger organisms with longer lifespans might have higher learning capacities. However, smaller organisms, like hover flies, demonstrate that learning ability is not solely dependent on size or lifespan. The social brain hypothesis is examined, proposing that social insects may have advanced learning abilities due to task specialization, but solitary insects, performing multiple tasks, may be more adept learners overall. [ABSTRACT FROM AUTHOR]

In Autism Spectrum Disorder (ASD) children feeding problems can be categorized as behavioural feeding disorders including food refusal, choking, gagging, expulsion and sensory-based feeding problems such as textural aversions. The oral stimulation increases oral motor organization improve muscle contractility as a result increases oral intake. Sensory characteristics of food such as taste, texture and aroma have effects on food acceptance. We present a case of 3.3 year old male with ASD having feeding issues such as refusal to consume food and would spit when tried to feed him forcefully and accepting only liquids in small quantities as compared to earlier since 55 days. The outcome measure used was Sensory Profile (Dunn, 1999) and Pediatric Eating Assessment Tool (PediEAT). Combined oral motor stimulation and aroma therapy was provided to the child for developing successful feeding skill. Conclusion: From the above pilot study it may be concluded that combination of oro-motor stimulation and aroma therapy is an effective intervention in decreasing oral sensory issues and thus improving feeding skills in children with ASD. [ABSTRACT FROM AUTHOR]

Background: Neck reflex points (NRPs) are 2 × 6 potentially tender areas of the neck, denominated NRP-C0 to NRP-C7. They are different from muscular trigger points and become tender in response to chronic trigeminal irritation. NRP examination has a high inter-rater reproducibility. We investigated the prevalence of NRPs in two populations to investigate their usefulness as a clinical test for trigeminal irritation. Methods: In total, 165 patients with chronic pain and 431 students were examined for NRP tenderness using a three-level pain scale: absent pain (PI = 0), mild tenderness (PI = 1), or marked tenderness (PI = 2). Results: In patients, we found more tender NRPs than in the student group (p < 0.001), and on the left side, more tender NRPs were found in NRP-C0–C4. Left and right NRPs appeared independently (kappa 0.1–0.4), except for NRP-C7 (kappa 0.55). Females had more tender NRPs (p < 0.001). Tenderness was independent of age, BMI, and pre-existing diseases. Conclusions: NRP tenderness occurs more frequently in patients than in students, independent from potential covariates. Our results, together with previous findings, support the use of NRP examination as a clinical test for chronic silent inflammation of the trigeminal region. These data provide a base for further studies investigating correlations of NRPs with clinical findings. [ABSTRACT FROM AUTHOR]

Aim: A clinical study was performed to test the usability of a smartphone eyescanning app at a needle exchange facility to detect drug use to support therapy. Methods: The study recruited 24 subjects who visited the facility one to three times, making a total of 40 visits. During each visit the subjects underwent testing for non-convergence (NC), nystagmus (NY), and pupillary light reflex (PLR) using a smartphone-based eHealth system. The collected eye data were transformed into key features that represent eye characteristics. During each visit, a time-line follow-back interview on recent drug use and a usability questionnaire were completed. Results: Technical usability of the smartphone eye-scanning app was good for PLR and NC, where key features were generated in 82%-91% of the cases. For NY, only 60% succeeded due to cognitive problems to follow instructions. In most cases, subjects were under the influence of drugs when participating in the tests, with an average of 2.4 different drugs ingested within the last 24 h. The key features from PLR could distinguish use of opioids from central stimulants. The usability questionnaire results indicate that 23 of the 24 subjects could perform the eye-scanning by themselves after a short training, even when under severe influence of drugs. The caregiver assessed that 20 out of the 24 challenging subjects could potentially perform these tests in an indoors, home-like environment. Conclusions: Smartphone-based eye-scanning is functional in a patient population with heavy drug use, also when under the influence of drugs. The use of central stimulants can be distinguished from the use of opioids. [ABSTRACT FROM AUTHOR]

Endothelin‐1 (ET‐1) and its receptors are linked to increases in sensitivity of the chemoreceptors to hypoxic stress and the development of hypertension in preclinical models. We hypothesized ET receptor antagonism would lower resting blood pressure (BP) as well as the acute BP response to chemoreflex stress. Twenty‐four men (31 ± 5 years, 26 ± 3 kg/m2) completed two study visits (control, bosentan). On each visit, BP was assessed under three conditions: (1) normoxia (FiO2 0.21), (2) chemoreflex excitation via hypoxia (FiO2 0.05–0.21), (3) chemoreflex inhibition via hyperoxia (FiO2 1.00). Bosentan increased plasma ET‐1 (0.94 ± 0.90 to 1.27 ± 0.62 pg/mL, p = 0.004), supporting receptor blockade. Resting diastolic (73 ± 5 to 69 ± 7 mmHg, p = 0.007) and mean (93 ± 7 to 88 ± 7 mmHg, p = 0.005) BP were reduced following bosentan compared to control with no change in systolic BP (p = 0.507). The mean BP response to both acute hypoxia (−0.48 ± 0.38 to −0.25 ± 0.31 mmHg/%, p = 0.004) and hyperoxia (area under the curve −93 ± 108 to −27 ± 66 AU, p = 0.018) were attenuated following bosentan. Acute ET receptor inhibition attenuates the rise in BP during chemoreflex excitation as well as the fall in BP during chemoreflex inhibition in healthy young men. These data support a role for ET‐1 in control of resting BP, possibly through a chemoreceptor‐mediated mechanism. [ABSTRACT FROM AUTHOR]

Purpose: Cough reflex testing (CRT) is an adjunct to the clinical swallowing evaluation (CSE), providing information on patients' risk of silent aspiration. CRT has been shown to influence diet recommendations, but in previous work, the many varied patient characteristics are not controlled. Therefore, the specific role of CRT results in these decisions remains unclear as this relationship has not been directly assessed. Method: An online survey was sent to speech language therapists working in dysphagia. Two patient cases were presented that differed only by the presence of risk factors for the development of aspiration pneumonia. For each patient case, there were three assessment scenarios: CSE information only, CSE information with a "pass" CRT result, and CSE information with a "fail" CRT result. Clinicians outlined their patient management plans for each of the six scenarios. Results: Ninety-seven data sets were used in the final analysis. A "fail" result was found to lead to the most restrictive patient management. Decisions made when provided with only CSE information were very similar to decisions made for a CSE with a "pass" result. Aspiration pneumonia risk factors were shown to influence decision making, with the low-risk patient more likely to be recommended a less restrictive diet. Conclusions: When information was available regarding silent aspiration risk, clinicians factored the results into their decision making. However, in the absence of a CRT result, airway sensation was assumed to be intact in the absence of information. This finding warrants further investigation given the impact this assumption may have on a patient's pulmonary health. [ABSTRACT FROM AUTHOR]

Context Increasing numbers of patients and caregivers are requesting transition to blenderized tube feeding. There is a lack of systematic reviews addressing the outcomes of blenderized tube feeding. Objective The aim was to evaluate the association of blenderized tube feeding on feeding tolerance in enterally fed pediatric patients. Data Sources A literature search for articles from 2012–2022 using PubMed, Medline, Embase, and CINAHL yielded 78 articles. Data Extraction A description and evaluation of the study's sample, purpose, and results were summarized for 9 studies using the Academy of Nutrition and Dietetics Evidence Analysis Library Worksheet. Data Analysis Nine studies were evaluated using the Evidence Analysis Library Quality Criteria checklist. Conclusions Studies demonstrated an improvement in vomiting (n = 7), gagging/retching and heartburn (n = 6), abdominal pain/upset and distension (n = 3), and diarrhea (n = 6) with blenderized tube feeding. The outcomes of blenderized tube feeding on gas (n = 5) and constipation (n = 9) are variable and remain unclear. Systematic Review Registration PROSPERO registration no. CRD42022369247. [ABSTRACT FROM AUTHOR]

Objectives: To investigate roles of brain carbon monoxide (CO), an endogenous gasotransmitter, in regulation of the rat micturition reflex. Methods: In urethane‐anesthetized (0.8 g/kg, ip) male rats, evaluation of urodynamic parameters was started 1 h before intracerebroventricular administration of CORM‐3 (CO donor) or ZnPP (non‐selective inhibitor of heme oxygenase, a CO producing enzyme) and continued for 2 h after the administration. We also investigated effects of centrally pretreated SR95531 (GABAA receptor antagonist) or SCH50911 (GABAB receptor antagonist) on the CORM‐3‐induced response. Results: CORM‐3 significantly prolonged intercontraction intervals (ICIs) without changing maximal voiding pressure (MVP), while ZnPP significantly shortened ICI and reduced single‐voided volume and bladder capacity without affecting MVP, post‐voided residual volume, or voiding efficiency. The ZnPP‐induced ICI shortening was reversed by CORM‐3. The CORM‐3‐induced ICI prolongation was significantly attenuated by centrally pretreated SR95531 or SCH50911, respectively. Conclusions: Brain CO can suppress the rat micturition reflex through brain γ‐aminobutyric acid (GABA) receptors. [ABSTRACT FROM AUTHOR]

(1) Background: Contracting diseases or being exposed to adverse environmental factors in the first year of life may impair the development of body posture and motor coordination. The purpose of this study was to evaluate the correlation between data on the speed of passive verticalization, the number of risk factors and the quality of development in the first year of life, and the results of the functional examination of these individuals in adolescence. (2) Methods: Two groups of 60 volunteers, aged 9–14 years, were examined by performing functional tests and the retrospective analysis of their development up to the age of 1 year. The first group consisted of patients diagnosed with postural defects. The control group consisted of healthy people of the same age who volunteered for this study. (3) Results: Statistical analysis showed statistically significant differences between groups in terms of posture (p = 0.001), motor coordination (p = 0.001), and accumulated primitive reflexes (p = 0.001), as well as a high correlation between these disorders and the quality of development in the first year of life. In the first group, for the ages of 3–6 months (r = 0.96; p = 0.001), 6–9 months (r = 0.871; p = 0.001), and 9–12 months (r = 0.806; p = 0.001), no significant correlations were found with the age of 0–3 months. In the second group, the results were as follows: 0–3 months (r = 0.748; p = 0.001), 3–6 months (r = 0.862 p = 0.001), 6–9 months (r = 0.698; p = 0.001), and 9–12 months (r = 0.740; p = 0.001). In the group of adolescents with posture defects, we observed an earlier time of passive verticalization and sitting, as well as more frequent use of loungers, seats, and walkers (p = 0.026). (4) Conclusions: The analysis of this study's data indicates that the development of body posture and motor coordination may be impaired due to accelerated and passive verticalization in the first year of life. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study was to determine whether providing realistic auditory or somatosensory cues to spatial location would affect measures of vestibulo-ocular reflex gain in a rotary chair testing (RCT) context. Method: This was a fully within-subject design. Thirty young adults age 18-30 years (16 men, 14 women by self-identification) completed sinusoidal harmonic acceleration testing in a rotary chair under five different conditions, each at three rotational frequencies (0.01, 0.08, and 0.32 Hz). We recorded gain as the ratio of the amplitude of eye movement to chair movement using standard clinical procedures. The five conditions consisted of two without spatial information (silence, tasking via headphones) and three with either auditory (refrigerator sound, tasking via speaker) or somatosensory (fan) information. Two of the conditions also included mental tasking (tasking via headphones, tasking via speaker) and differed only in terms of the spatial localizability of the verbal instructions. We used linear mixed-effects modeling to compare pairs of conditions, specifically examining the effects of the availability of spatial cues in the environment. This study was preregistered on Open Science Framework (https://osf.io/2gqcf/). Results: Results showed significant effects of frequency in all conditions (p < .05), but the only pairs of conditions that were significantly different were those including tasking in one condition but not the other (e.g., tasking via headphones vs. silence). Post hoc equivalence testing showed that the lack of significance in the other comparisons could be confirmed as not meaningfully different. Conclusions: These findings suggest that the presence of externally localizable sensory information, whether auditory or somatosensory, does not affect measures of gain in RCT to any relevant degree. However, these findings also contribute to the increasing body of evidence suggesting that mental engagement ("tasking") does increase gain whether or not it is provided via localizable instructions. [ABSTRACT FROM AUTHOR]

Purpose: The objective of this study was to determine the normative vestibulo- ocular reflex gain output values of the computerized rotational head impulse test (crHIT) with stationary visual targets (earth bound) in healthy participants in each decade age band of life: 10-19, 20-29, 30-39, 40-49, 50-59, 60-69, and 70+ years. Method: Seventy-seven community-dwelling participants (10-85 years of age) with normal lateral semicircular canal (SCC) functioning and no symptoms or history of vestibular dysfunction were recruited through convenience sampling and assessed with the crHIT using stationary targets. These participants were assessed using two standard protocols in a randomized order. Results: Results from 77 participants (Mage = 46 years; 43 women, 34 men) were analyzed. Pearson's correlation coefficient and simple linear regression indicated a statistically significant relationship between crHIT gain output and age (p >.05) for right gain, 1030°/s², and left gain, 1005°/s². Although a statistically significant relationship was found, the slope was minor, demonstrating that the clinical effect of age on crHIT gain output was insignificant. Furthermore, no statistically significant relationship exists between crHIT gain output and gender (p > .05). Age-dependent normative data were calculated using the 2.5th and 97.5th confidence interval (CI) percentile method. The responses of angular vestibulo-ocular reflex (aVOR) gain values for crHIT are expected to occur within the range for lower limit reference interval (RI) of 0.85-0.9 and upper limit RI of 1.11-1.18 for 1030°/s² and lower limit RI of 0.86-0.92 and upper limit RI of 1.13-1.16 for 1005°/s² .It can be expected that 90% CI of the population with normal lateral SCC function- ing will have aVOR gain values that fall within this range. Conclusion: Despite a statistically significant relationship that exists with aVOR gain output and age, the changes are minor, declining by 0.0088 units per 10 years, justifying the same normative data for all decade age bands. [ABSTRACT FROM AUTHOR]

The proprioceptive sensory reflex (e.g. stretch reflex) plays an important role in perturbed arm stabilization. Neuroscience studies have widely identified the heteronymous spinal pathways in the human arm, which may contribute to stabilized movement. However, their interactions in living systems pose challenges for specific functional investigations through human experiments. Therefore, this paper concentrates on understanding the effects of two heteronymous pathways, specifically the transmission of monoarticular sensory feedback to innervate biarticular muscles, using the robot. We replicate specific reflex pathways on a 2-DoF musculoskeletal robot equipped with pneumatic artificial muscles. By adjusting the weights of pathways, which resemble human motor control, we evaluate our robot arm performance under the forearm and upper arm disturbances. The outcomes validate their effects on regulating biarticular muscle stimulation, resulting in more stable and coordinated end-effectory trajectories. These reflexive pathways provide insights into the mechanisms underlying human arm perturbations and stabilization. Additionally, the proposed bioinspired system with applicable reflex weights holds great potential in the adaptive response of musculoskeletal robots, guiding robotics researchers in controller design. [ABSTRACT FROM AUTHOR]

The nociceptive withdrawal reflex (NWR) is a protective limb withdrawal response triggered by painful stimuli, used to assess spinal nociceptive excitability. Conventionally, the NWR is understood as having two reflex responses: a short-latency Aβ-mediated response, considered tactile, and a longer-latency Aδ-mediated response, considered nociceptive. However, nociceptors with conduction velocities similar to Aβ tactile afferents have been identified in human skin. In this study, we investigated the effect of a preferential conduction block of Aβ fibers on pain perception and NWR signaling evoked by intradermal electrical stimulation in healthy participants. We recorded a total of 198 NWR responses in the intact condition, and no dual reflex responses occurred within our latency bandwidth (50–150 ms). The current required to elicit the NWR was higher than the perceptual pain threshold, indicating that NWR did not occur before pain was felt. In the block condition, when the Aβ-mediated tuning fork sensation was lost while Aδ-mediated nonpainful cooling was still detectable (albeit reduced), we observed that the reflex was abolished. Further, short-latency electrical pain intensity at pre-block thresholds was greatly reduced, with any residual pain sensation having a longer latency. Although electrical pain was unaffected at suprathreshold current, the reflex could not be evoked despite a two-fold increase in the pre-block current and a five-fold increase in the pre-block pulse duration. These observations lend support to the possible involvement of Aβ-fiber inputs in pain and reflex signaling. [ABSTRACT FROM AUTHOR]

Background: Acute and complete unilateral vestibular deafferentation induces a significant change in ipsilateral vestibuloocular reflex gain, making the patient unable to stabilize gaze during active or passive head movements. This inability creates the illusion that the visual environment is moving, resulting in persistent visual discomfort during rapid angular or linear acceleration of the head. This is known as oscillopsia. Our objective was to understand if the spontaneous sensation of oscillopsias after complete unilateral vestibular deafferentation by vestibular neurotomy at 5 days (D5) and at 3 months (M3) is correlated with the loss of vestibuloocular reflex gain and dynamic visual acuity. Methods: Retrospective cohort study was conducted in an otolaryngology tertiary care center (2019-2022) on patients with complete unilateral vestibular loss by vestibular neurotomy. They were divided into 2 groups according to the presence (group G1) or absence (group G2) of a spontaneous complaint of oscillopsia assessed at M3. Severity of oscillopsias evaluated by Oscillopsia Severity Questionnaire. Vestibuloocular reflex gain based on video head impulse test (vHIT) and the dynamic visual acuity were measured for each group at D5 and M3. Categorical variables were compared using χ2 test and quantitative variables using the nonparametric Wilcoxon-Mann-Whitney test. Results: All patients have a complete vestibular deafferentation at D5 and M3. At D5 (G1 = 8 patients, G2 = 5 patients), there is no significant difference for ipsilateral and contralateral vestibuloocular reflex gains and dynamic visual acuity losses. The Oscillopsia Severity Questionnaire was 2.68 ± 1.03 in G1 and 1.23 ± 1.03 in G2 (P <.05). At M3 (G1 = 9 patients, G2 = 6 patients), there is no significant difference between groups for epidemiologic and clinical data and for vestibuloocular reflex and dynamic visual acuity losses. The Oscillopsia Severity Questionnaire was 2.10 ± 0.63 in G1 and 1.24 ± 0.28 in G2 (P <.05). Conclusions: The spontaneous disabling sensation of oscillopsia after complete unilateral vestibular loss is well assessed by the Oscillopsia Severity Questionnaire but cannot be explained by objective vestibular tests assessing vestibuloocular reflex gain (vHIT) or dynamic visual acuity loss at D5 or M3. Further studies are needed to measure the sensation of oscillopsia under real-life conditions and to identify the factors responsible for its persistence. Trial registration: Retrospectively registered. [ABSTRACT FROM AUTHOR]

Introduction: Sex-specific patterns in respiratory conditions, such as asthma, COPD, cystic fibrosis, obstructive sleep apnea, and idiopathic pulmonary fibrosis, have been previously documented. Animal models of acute lung injury (ALI) have offered insights into sex differences, with male mice exhibiting distinct lung edema and vascular leakage compared to female mice. Our lab has provided evidence that the chemoreflex is sensitized in male rats during the recovery from bleomycin-induced ALI, but whether sex-based chemoreflex changes occur post-ALI is not known. To bridge this gap, the current study employed the bleomycin-induced ALI animal model to investigate sex-based differences in chemoreflex activation during the recovery from ALI. Methods: ALI was induced using a single intra-tracheal instillation of bleomycin (bleo, 2.5 mg/Kg) (day 1). Resting respiratory frequency (fR) was measured at 1-2 days pre-bleo, day 7 (D7) post-bleo, and 1 month (1 mth) post-bleo. The chemoreflex responses to hypoxia (10% O2, 0%CO2) and normoxic-hypercapnia (21%O2, 5%CO2) were measured before bleo administration (pre-bleo) and 1 mth post-bleo using whole-body plethysmography. The apnea-hypopnea Index (AHI), post-sigh apneas, and sighs were measured at each time point. Results: Therewere no significant differences in resting fR between male and female rats at the pre-bleo time point or in the increase in resting fR at D7 post-bleo. At 1mth post-bleo, the resting fR was partially restored in both sexes but the recovery towards normal ranges of resting fR was significantly lower in male rats. The AHI, post-sigh apneas, and sighs were not different between male and female rats pre-bleo and 1mth post-bleo. However, at D7 post-bleo, themale rats exhibited a higher AHI than female rats. Bothmale and female rats exhibited a sensitized chemoreflex in response to hypoxia and normoxic-hypercapnia with no significant differences between sexes. Conclusion: A sex difference in resting ventilatory parameters occurs post ALI with a prolonged increase in resting fR and larger AHI in male rats. On the other hand, we did not find any sex differences in the chemoreflex sensitization that occurs at 1 mth post-bleo. This work contributes to a better understanding of sex-based variations in lung disorders. [ABSTRACT FROM AUTHOR]

Background: Hormonal contraceptives (HCs) and the menstrual cycle have been suggested to affect symptom severity and postconcussion recovery. Additionally, hormones have been a suggested rationale for sex differences between female and male athletes on concussion assessment. Researchers have yet to explore the effects of HC use on baseline symptomatology, including symptom reporting and provocation. Purpose: To examine the influence of HC use on a baseline symptom reporting and vestibular/ocular provocation battery. Study Design: Cross-sectional study; Level of evidence, 3. Methods: A total of 61 college-aged individuals (21 HC-using women, 21 non–HC-using women, 19 men) were administered a baseline symptom battery consisting of the Post-Concussion Symptom Scale (PCSS), Headache Impact Test-6 (HIT-6), Pediatric Vestibular Symptom Questionnaire (PVSQ), and Vestibular/Ocular Motor Screening (VOMS). The main outcome measures consisted of PCSS symptom reporting (total symptoms, symptom severity score, and symptom factors), HIT-6 and PVSQ total scores, and VOMS item (ie, saccades, convergence, or vestibular/ocular reflex) symptom provocation scores. Results: Significant differences were reported on HIT-6, with the highest headache reporting in the HC group (P =.026). On the PVSQ, the HC group also reported greater dizziness and unsteadiness symptoms than the non-HC group (P =.023). Similar findings existed on the PCSS, with the HC group reporting greater total symptoms (P <.001), symptom severity (P <.001), and vestibular-somatic (P =.024), cognitive-sensory (P =.004), sleep-arousal (P =.001), and affective (P <.001) factors compared with the non-HC group. Smooth pursuit (ie, following finger smoothly with eyes) was the only VOMS items with differences between groups (P =.003), with the HC group having greater provocation compared with non-HC users (P =.020). Conclusion: HC use was associated with overall symptomatology and worse self-reported symptoms on vestibular-related inventories and concussion symptom scales and factors when compared with non-HC users and male controls. Additionally, HC users reported higher VOMS provocation scores on the smooth pursuit item than non-HC users and male controls. [ABSTRACT FROM AUTHOR]

Purpose: This pilot study aimed to determine the capacity of automated infrared pupillometry (AIP) alone and in combination with transcranial doppler (TCD) on admission to rule out need for intense neuroAQ2 critical care (INCC) in severe traumatic brain injury (TBI). Methods: In this observational pilot study clinicians performed AIP and TCD measurements on admission in blunt TBI patients with a Glasgow Coma Score (GCS) < 9 and/or motor score < 6. A Neurological Pupil index (NPi) < 3, Pulsatility Index (PI) > 1,4 or diastolic blood flow velocity (dV) of < 20 cm/s were used to rule out the need for INCC (exceeding the tier 0 Seattle Consensus Conference). The primary outcome was the negative likelihood ratio (nLR) of NPi < 3 alone or in combination with TCD to detect need for INCC. Results: A total of 69 TBI patients were included from May 2019 to September 2020. Of those, 52/69 (75%) median age was 45 [28–67], median prehospital GCS of 7 [5–8], median Injury Severity Scale of 13.0 [6.5–25.5], median Marshall Score of 4 [3–5], the median Glasgow Outcome Scale at discharge was 3 [1–5]. NPi < 3 was an independent predictor of INCC. NPi demonstrated a nLR of 0,6 (95%CI 0.4–0.9; AUROC, 0.65, 95% CI 0.51–0.79), a combination of NPi and TCD showed a nLR of 0.6 (95% CI 0.4–1.0; AUROC 0.67 95% CI 0.52–0.83) to predict INCC. Conclusion: This pilot study suggests a possible useful contribution of NPi to determine the need for INCC in severe blunt TBI patients on admission. [ABSTRACT FROM AUTHOR]

A 62-year-old woman had 6 months of proximal weakness, fatigue and occasional diplopia, symptoms normally suggesting myasthenia gravis or inflammatory myopathy. Postexercise reflex facilitation is a bedside clinical sign that points to a diagnosis of the rarer alternative, Lambert-Eaton myasthenic syndrome (LEMS). We confirmed this diagnosis using electrodiagnostic short exercise testing and serum assay for voltage-gated calcium channel antibodies. Further investigation identified a small cell neuroendocrine carcinoma of the gallbladder, not previously associated with LEMS. Postexercise reflex facilitation is an important bedside clinical finding that helps clinicians to distinguish LEMS from its mimics. [ABSTRACT FROM AUTHOR]

The work in the technological sewing process is carried out on machine systems characterised by machine–hand work, where the worker and the machine work simultaneously. Such a work system requires a high level of responsibility in terms of quality, quantity, and the correct and timely execution of work, which requires workers to have fast and accurate reflexes, as well as exceptionally good psychomotor and visual skills. By applying the basic movements of the Methods-Time Measurement (MTM) system, the elaborated standard sets of hand sub-operations included in technological sewing operations, and the method of determining normal times for straight seams (RAV) and curved seams (ZAK), it is possible to determine the working method and time norm of individual technological sewing operations. The MTM Calculator software was developed to facilitate the determination of working methods and time norms on the basis of the MTM system. It can be used to quickly calculate the production time for a technological sewing operation. [ABSTRACT FROM AUTHOR]

Introduction: Recognizing testicular torsion is extremely important in patients presenting to the emergency department (ED) with acute scrotal pain. Traditional manual detorsion techniques are frequently employed by emergency physicians but are not always successful. Delays in detorsion increase the risk of testicular infarction and infertility, and the need for orchiectomy. Novel techniques such as the testicular traction technique have been described as a potential solution for difficult-todetorse testicles. Case Report: Our case report describes a 20-year-old male with no significant past medical history who presented to a rural ED with acute, atraumatic testicular pain secondary to testicular torsion with an intact cremasteric reflex. After confirming the diagnosis using Doppler ultrasound, manual detorsion using the traditional “open book” technique was attempted and unsuccessful. The patient was subsequently successfully detorsed using the novel testicular traction technique. Conclusion: The testicular traction technique is a safe, rapid, and effective primary or adjunctive technique in manual testicular detorsion. Given the time-sensitive nature of testicular torsions, adjunctive techniques play a crucial role in managing challenging detorsions, particularly in resource-limited rural settings with limited access to urologic services. Although it is commonly thought that the cremasteric reflex is absent in testicular torsions, it may be present in rare circumstances, and its presence should not be an absolute in ruling out torsion. [ABSTRACT FROM AUTHOR]

Objective: Depth camera-based measurement has demonstrated efficacy in automated assessment of upper limb Fugl-Meyer Assessment for paralysis rehabilitation. However, there is a lack of adequately sized studies to provide clinical support. Thus, we developed an automated system utilizing depth camera and machine learning, and assessed its feasibility and validity in a clinical setting. Design: Validation and feasibility study of a measurement instrument based on single cross-sectional data. Setting: Rehabilitation unit in a general hospital Participants: Ninety-five patients with hemiparesis admitted for inpatient rehabilitation unit (2021–2023). Main measures: Scores for each item, excluding those related to reflexes, were computed utilizing machine learning models trained on participant videos and readouts from force test devices, while the remaining reflex scores were derived through regression algorithms. Concurrent criterion validity was evaluated using sensitivity, specificity, percent agreement and Cohen's Kappa coefficient for ordinal scores of individual items, as well as correlations and intraclass correlation coefficients for total scores. Video-based manual assessment was also conducted and compared to the automated tools. Result: The majority of patients completed the assessment without therapist intervention. The automated scoring models demonstrated superior validity compared to video-based manual assessment across most items. The total scores derived from the automated assessment exhibited a high coefficient of 0.960. However, the validity of force test items utilizing force sensing resistors was relatively low. Conclusion: The integration of depth camera technology and machine learning models for automated Fugl-Meyer Assessment demonstrated acceptable validity and feasibility, suggesting its potential as a valuable tool in rehabilitation assessment. [ABSTRACT FROM AUTHOR]

A biologically-inspired actuation system, including muscles, spinal reflexes, and vestibular feedback, may be capable of achieving more natural gait mechanics in powered prostheses or exoskeletons. In this study, we developed a Virtual Muscle Reflex (VMR) system to control ankle torque and tuned it using data from human responses to anteroposterior mechanical perturbations at three walking speeds. The system consists of three Hill-Type muscles, simulated in real time, and uses feedback from ground reaction force and from stretch sensors on the virtual muscle fibers. Controller gains, muscle properties, and reflex/vestibular time delays were optimized using Covariance Matrix Adaptation (CMA) to minimize the difference between the VMR torque output and the torque measured from the experiment. We repeated the procedure using a conventional finite-state impedance controller. For both controllers, the coefficient of determination ( R 2 ) and root-mean-square error (RMSE) was calculated as a function of time within the gait cycle. The VMR had lower RMSE than the impedance controller in 70%, and in 60% of the trials, the R 2 of the VMR controller was higher than for the impedance controller. We concluded that the VMR system can better reproduce the human responses to perturbations than the impedance controller. [ABSTRACT FROM AUTHOR]

Background: Cognitive impairment in the elderly may lead to potential increased sensitivity to anesthetic agents targeting receptors associated with cognition. This study aimed to explore the effect of cognitive status on propofol consumption during surgery in elderly patients. Methods: Sixty elderly patients scheduled for laparoscopic radical prostatectomy were allocated to either a cognitively normal [CogN, Montreal Cognitive Assessment (MoCA) score ≥26] or cognitively impaired (CogI, MoCA <26) group. Propofol was administered via target-controlled infusion to maintain a bispectral index (BIS) between 55-65 during surgery. Propofol consumption was recorded at three time points: T1 (abolished eyelash reflex), T2 (BIS = 50), T3 (extubation). BIS values at eyelash reflex abolition were also recorded. Postoperative MoCA, Visual Analogue Scale (VAS) scores, and remifentanil/sufentanil consumption were assessed. Results: BIS values before induction were similar between CogN and CogI groups. However, at eyelash reflex abolition, BIS was significantly higher in CogI than CogN (mean ± SD: 65.3 ± 7.2 vs. 61.1 ± 6.8, p = 0.031). Propofol requirement to reach BIS 50 was lower in CogI vs. CogN (1.24 ± 0.19 mg/kg vs. 1.46 ± 0.12 mg/kg, p = 0.003). Postoperative MoCA, VAS scores, and remifentanil/sufentanil consumption did not differ significantly between groups. Conclusion: Compared to cognitively intact elderly, those with cognitive impairment exhibited higher BIS at eyelash reflex abolition and required lower propofol doses to achieve the same BIS level, suggesting increased propofol sensitivity. Cognitive status may impact anesthetic medication requirements in the elderly. [ABSTRACT FROM AUTHOR]

Background Cerebral microvascular dysfunction may contribute to depression via disruption of brain structures involved in mood regulation, but evidence is limited. We investigated the association of retinal microvascular function, a proxy for microvascular function in the brain, with incidence and trajectories of clinically relevant depressive symptoms. Methods Longitudinal data are from The Maastricht Study of 5952 participants (59.9 ± 8.5 years/49.7% women) without clinically relevant depressive symptoms at baseline (2010–2017). Central retinal arteriolar equivalent and central retinal venular equivalent (CRAE and CRVE) and a composite score of flicker light-induced retinal arteriolar and venular dilation were assessed at baseline. We assessed incidence and trajectories of clinically relevant depressive symptoms (9-item Patient Health Questionnaire score ⩾10). Trajectories included continuously low prevalence (low, n = 5225 [87.8%]); early increasing, then chronic high prevalence (early-chronic, n = 157 [2.6%]); low, then increasing prevalence (late-increasing, n = 247 [4.2%]); and remitting prevalence (remitting, n = 323 [5.4%]). Results After a median follow-up of 7.0 years (range 1.0–11.0), 806 (13.5%) individuals had incident clinically relevant depressive symptoms. After full adjustment, a larger CRAE and CRVE were each associated with a lower risk of clinically relevant depressive symptoms (hazard ratios [HRs] per standard deviation [ s.d. ]: 0.89 [95% confidence interval (CI) 0.83–0.96] and 0.93 [0.86–0.99], respectively), while a lower flicker light-induced retinal dilation was associated with a higher risk of clinically relevant depressive symptoms (HR per s.d. : 1.10 [1.01–1.20]). Compared to the low trajectory, a larger CRAE was associated with lower odds of belonging to the early-chronic trajectory (OR: 0.83 [0.69–0.99]) and a lower flicker light-induced retinal dilation was associated with higher odds of belonging to the remitting trajectory (OR: 1.23 [1.07–1.43]). Conclusions These findings support the hypothesis that cerebral microvascular dysfunction contributes to the development of depressive symptoms. [ABSTRACT FROM AUTHOR]

Rhythms are the most natural cue for temporal anticipation because many sounds in our living environment have rhythmic structures. Humans have cortical mechanisms that can predict the arrival of the next sound based on rhythm and periodicity. Herein, we showed that temporal anticipation, based on the regularity of sound sequences, modulates peripheral auditory responses via efferent innervation. The medial olivocochlear reflex (MOCR), a sound-activated efferent feedback mechanism that controls outer hair cell motility, was inferred noninvasively by measuring the suppression of otoacoustic emissions (OAE). First, OAE suppression was compared between conditions in which sound sequences preceding the MOCR elicitor were presented at regular (predictable condition) or irregular (unpredictable condition) intervals. We found that OAE suppression in the predictable condition was stronger than that in the unpredictable condition. This implies that the MOCR is strengthened by the regularity of preceding sound sequences. In addition, to examine how many regularly presented preceding sounds are required to enhance the MOCR, we compared OAE suppression within stimulus sequences with 0–3 preceding tones. The OAE suppression was strengthened only when there were at least three regular preceding tones. This suggests that the MOCR was not automatically enhanced by a single stimulus presented immediately before the MOCR elicitor, but rather that it was enhanced by the regularity of the preceding sound sequences. [ABSTRACT FROM AUTHOR]

We previously showed that orexin neurons are activated by hypoxia and facilitate the peripheral chemoreflex (PCR)-mediated hypoxic ventilatory response (HVR), mostly by promoting the respiratory frequency response. Orexin neurons project to the nucleus of the solitary tract (nTS) and the paraventricular nucleus of the hypothalamus (PVN). The PVN contributes significantly to the PCR and contains nTS-projecting corticotropin-releasing hormone (CRH) neurons. We hypothesized that in male rats, orexin neurons contribute to the PCR by activating nTS-projecting CRH neurons. We used neuronal tract tracing and immunohistochemistry (IHC) to quantify the degree that hypoxia activates PVN-projecting orexin neurons. We coupled this with orexin receptor (OxR) blockade with suvorexant (Suvo, 20 mg/kg, i.p.) to assess the degree that orexin facilitates the hypoxia-induced activation of CRH neurons in the PVN, including those projecting to the nTS. In separate groups of rats, we measured the PCR following systemic orexin 1 receptor (Ox1R) blockade (SB-334867; 1 mg/kg) and specific Ox1R knockdown in PVN. OxR blockade with Suvo reduced the number of nTS and PVN neurons activated by hypoxia, including those CRH neurons projecting to nTS. Hypoxia increased the number of activated PVN-projecting orexin neurons but had no effect on the number of activated nTS-projecting orexin neurons. Global Ox1R blockade and partial Ox1R knockdown in the PVN significantly reduced the PCR. Ox1R knockdown also reduced the number of activated PVN neurons and the number of activated tyrosine hydroxylase neurons in the nTS. Our findings suggest orexin facilitates the PCR via nTS-projecting CRH neurons expressing Ox1R. [ABSTRACT FROM AUTHOR]