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Objective: To identify the effects of chronic pain levels on static and dynamic postural (DP) control in individuals with chronic ankle instability (CAI). Design: Cross-sectional study. Setting: Controlled laboratory. Participants: Sixty participants were divided into the following 3 groups: 20 high pain individuals with CAI (high pain), 20 low pain individuals with CAI (low pain), and 20 healthy controls (control). Independent Variables: Groups (CAI with high pain, CAI with low pain, and control) and visual conditions (eyes open and closed) for single-leg stance. Main OutcomeMeasures: Participants performed single-leg stance with eyes open and closed, the star excursion balance test, and single-leg hop to stabilization. Results: The high pain group experienced worse self-reported outcomes, including Foot and Ankle Ability Measure activities of daily living and sports, than the low pain and control groups. Regardless of visual condition, both the high and low pain groups exhibited decreased static postural control in mediolateral (ML) compared with the control group. Specifically, the high pain group showed decreased static postural control in ML under closed eyes compared with the low pain and the control groups. The high pain group showed less reach distance than the control group and increased DP control in vertical and overall DP stability index compared with the low and control groups. Conclusions: Chronic pain can significantly affect both static and DP control in individuals with CAI. Therefore, clinicians should consider chronic pain as one of the factors affecting postural control in individuals with CAI. [ABSTRACT FROM AUTHOR]

In the first days after a spaceflight (SF), re-entry motion sickness and motor coordination problems reflect the need to readapt back to the natural gravitational state. Gravity is a natural stimulus for the receptors of vestibular apparatus, which plays an important role in multisensory interactions. Changes indicating an increase in excitability of the vestibular apparatus during SF (Kornilova et al., 2017) suggest a high probability of the occurrence of gaze-evoked nystagmus after prolonged SF. Russian-American experiment "Field Test" included a nystagmus test. 22 ISS crewmembers (14 Russian cosmonauts and 8 astronauts; flight duration 159.8 ± 19.5 days) participated in the experiment. The study was conducted twice before flight and several times after flight, starting within 3 h after landing. In a seated position, astronauts tracked with their eyes only (without moving their head) horizontal and vertical movements of the researcher's finger from the central position to the gaze end points (right, left, upper). Eye movements were recorded with a video camera. The videos were analyzed qualitatively for presence of nystagmus. Preflight, gaze-evoked nystagmus was detected in 5 people, the greatest changes were observed on landing day. 10 crewmembers exhibited nystagmus in the extreme left gaze position and 13 crewmembers – in the extreme right gaze position (partial recovery was observed 1–4 days after SF). A noticeable decrease in the frequency of manifestation of the nystagmus was observed only 10–13 days after landing (n = 16). Gaze-evoked nystagmus is usually considered a clinical sign of cerebellar alterations. However, it is often described in healthy people with a prevalence of up to 21 %. In a similar study involving 18 astronauts, participants of long-term SF, the frequency of occurrence of gaze-evoked nystagmus also increased in the first hours after SF (Reschke, Good and Clement, 2017). However, in this study, a detailed analysis of the presence of nystagmus in various directions was conducted for the first time. Of particular interest is the frequent detection of a gaze-evoked nystagmus in the right position after SF - this phenomenon may be a sign of presence of a central vestibular imbalance (Robinson et al., 1984), which also occurs in patients with cerebellar disorders (Bayer and Dietrich, 2011). The results allow us to expand our understanding of the severity and frequency of vestibular disorders and the dynamics of their recovery after prolonged SF. • The results of the Russian-American space experiment "Field Test". • Most often, gaze-evoked nystagmus occurs in the extreme right position of the gaze. • Within the first 3 h after landing the most pronounced changes were observed. [ABSTRACT FROM AUTHOR]

Introduction: Bed rest can be used as a ground-based analog of the body unloading associated with spaceflight. In this study, we determined how strict head-down tilt bed rest affects subjects' performance of functional tests (sit-tostand, tandem walk, walk-and-turn, dynamic posturography) that challenge astronauts' balance control systems immediately after they return from space. Methods: Forty-seven participants were assessed before and a few hours after 30 days of 6° head down tilt bed rest at the DLR:envihab facility. During this bed rest study, called SANS-CM, the participants were divided into 4 groups that either a) were positioned in head-down tilt continuously throughout the 30 days; b) sat upright for 6 h a day; c) were exposed to lower body negative pressure (LBNP) for 6 h a day; or d) exercised for 60 min and then wore venous-occlusive cuffs for 6 h a day. Results: Results showed that strict head-down tilt bed rest caused deficits in performance of functional tasks that were similar to those observed in astronauts after spaceflight. Seated upright posture mitigated these deficits, whereas exercise or LBNP and cuffs partly mitigated them. Discussion: These data suggest that more direct, active sensorimotor-based countermeasures may be necessary to maintain preflight levels of functional performance after a long period of body unloading. [ABSTRACT FROM AUTHOR]

Rhythm is essential in early music education. To acquire rhythm abilities, the synchronisation between body and rhythm patterns is fundamental. Extensive research has shown the link between the auditory-motor system and rhythm acquisition; however, other sensorimotor systems also improve rhythm skills. Rhythm acquisition can be trained using new technologies, such as video games; however, most of these use mainly auditory stimuli to improve it. Therefore, in this work, we explore tactile stimuli to improve rhythm skills using a video game and how visual elements affect rhythm perception using different stimuli. We evaluate and compare the synchronisation of 27 participants following either vibrotactile or auditory stimuli emitted through a rhythm video game in two difficulty levels and we evaluated the user experience. Consistent with the literature, our results indicate that participants synchronised slightly better using auditory than vibrotactile stimuli and players' performance was better when they had visual guides. A fatigue effect persisted and increased over playtime in both conditions. In the current study, usability measures indicate no significant differences. These findings suggest that vibrotactile stimuli are also suitable to train rhythm skills in a video game environment and the game-elements play an important role in players' performance. [ABSTRACT FROM AUTHOR]

"Are you LISTENING?" may be one of the most frequent questions preschoolers hear from their parents and teachers, but can children be taught to listen carefully—and thus better comprehend language—and if so, what changes occur in their brains? Twenty-seven four- and five-year-old children were taught a language simulation strategy to use while listening to stories: first, they practiced moving graphics on an iPad to correspond to the story actions, and then they practiced imagining the movements. Compared to a control condition, children in the intervention answered comprehension questions more accurately when imagining moving the graphics and on a measure of transfer using a new story without any instruction and with only immovable graphics. Importantly, for children in the intervention, the change in comprehension from the first to the sixth day was strongly correlated with changes in EEG mu and alpha desynchronization, suggesting changes in motor and visual processing following the intervention. Thus, the data are consistent with our hypothesis that a language simulation listening comprehension intervention can improve children's listening comprehension by teaching children to align visual and motor processing with language comprehension. [ABSTRACT FROM AUTHOR]

Therapeutic interventions for individuals with chronic ankle instability (CAI) are recommended to improve muscle strength, postural control, and range of motion. However, their effects on neuromechanics during a drop landing remain unclear. In addition, even though therapeutic interventions with stroboscopic glasses appear to effectively improve postural control, how they affect landing neuromechanics remains unclear. To identify the effect of balance training with stroboscopic glasses on neuromechanics during a single-legged drop landing in patients with CAI. Randomized controlled clinical trial. Laboratory. A total of 50 participants with CAI were randomly assigned to 1 of 2 groups: strobe (n = 25; age = 22 ± 3 years, height = 174.7 ± 8.2 cm, mass = 71.8 ± 12.2 kg) or control (n = 25; age = 21 ± 2 years, height = 173.1 ± 8.3 cm, mass = 71.1 ± 13.5 kg). The 4-week rehabilitation (3 sessions per week) included hop-based tasks and single-legged stance. The strobe group wore stroboscopic glasses during the training, whereas the control group did not. Ankle-, knee-, and hip-joint kinematics and 4 lower extremity muscle activations 150 milliseconds before and after initial contact during a single-legged drop landing in the 2 groups. The strobe group showed greater eversion (from 150 milliseconds before to 30 milliseconds after initial contact) and dorsiflexion (from 30 to 96 milliseconds after initial contact) angles and peroneal longus (from 35 milliseconds before to 5 milliseconds after initial contact) and tibialis anterior (from 0 to 120 milliseconds after initial contact) activation in the posttest than the pretest. Patients with CAI who underwent a 4-week rehabilitation with stroboscopic glasses demonstrated changes in neuromechanics, including increased ankle-dorsiflexion and -eversion angles and tibialis anterior and peroneus longus activation, during a single-legged drop landing. This finding suggests that use of stroboscopic glasses during rehabilitation could help patients with CAI develop safe landing mechanics. [ABSTRACT FROM AUTHOR]

The perceptual and motor coordination problems experienced following return from spaceflight reflect the sensory adaptation to altered gravity. The purpose of this study was to develop a ground-based analog that replicates similar sensorimotor impairment using a standard measures test battery and subjective feedback from experienced crewmembers. This Sensorimotor Disorientation Analog (SDA) included varying levels of sensorimotor disorientation through combined vestibular, visual, and proprioceptive disruptions. The SDA was evaluated on five previously flown astronauts to compare with their postflight experience and functional motor performance immediately (Return (R)+0 days) and +24 h (R+1) after landing. The SDA consisted of galvanic vestibular stimulation (GVS), visual disruption goggles, and a weighted suit to alter proprioceptive feedback and replicate perceived heaviness postflight. Astronauts reported that GVS alone replicated ~50-90% of their postflight performance with the weighted suit fine-tuning the experience to replicate an additional 10%-40% of their experience. Astronauts did not report feeling that the disruption goggles represented either the visual disruptions or illusory sensations that they experienced, nor did they impact motor performance in postflight tasks similarly. Based on these results, we recommend an SDA including the GVS and the weighted suit. These results provide a more realistic and portable SDA framework to provide transient spaceflight-relevant sensorimotor disruptions for use in countermeasure testing and as a pre-flight training tool. [ABSTRACT FROM AUTHOR]

Optimal feedback control provides an abstract framework describing the architecture of the sensorimotor system without prescribing implementation details such as what coordinate system to use, how feedback is incorporated, or how to accommodate changing task complexity. We investigate how such details are determined by computational and physical constraints by creating a model of the upper limb sensorimotor system in which all connection weights between neurons, feedback, and muscles are unknown. By optimizing these parameters with respect to an objective function, we find that the model exhibits a preference for an intrinsic (joint angle) coordinate representation of inputs and feedback and learns to calculate a weighted feedforward and feedback error.We further show that complex reaches around obstacles can be achieved by augmenting our model with a path-planner based on via points. The path-planner revealed "avoidance" neurons that encode directions to reach around obstacles and "placement" neurons that make fine-tuned adjustments to via point placement. Our results demonstrate the surprising capability of computationally constrained systems and highlight interesting characteristics of the sensorimotor system. [ABSTRACT FROM AUTHOR]

IntroductionBed rest can be used as a ground-based analog of the body unloading associated with spaceflight. In this study, we determined how strict head-down tilt bed rest affects subjects’ performance of functional tests (sit-to-stand, tandem walk, walk-and-turn, dynamic posturography) that challenge astronauts’ balance control systems immediately after they return from space.MethodsForty-seven participants were assessed before and a few hours after 30 days of 6° head down tilt bed rest at the DLR:envihab facility. During this bed rest study, called SANS-CM, the participants were divided into 4 groups that either a) were positioned in head-down tilt continuously throughout the 30 days; b) sat upright for 6 h a day; c) were exposed to lower body negative pressure (LBNP) for 6 h a day; or d) exercised for 60 min and then wore venous-occlusive cuffs for 6 h a day.ResultsResults showed that strict head-down tilt bed rest caused deficits in performance of functional tasks that were similar to those observed in astronauts after spaceflight. Seated upright posture mitigated these deficits, whereas exercise or LBNP and cuffs partly mitigated them.DiscussionThese data suggest that more direct, active sensorimotor-based countermeasures may be necessary to maintain preflight levels of functional performance after a long period of body unloading.

Balanced posture without dizziness is achieved via harmonious coordination of visual, vestibular, and somatosensory systems. Specific frequency bands of center of pressure (COP) signals during quiet standing are closely related to the sensory inputs of the sensorimotor system. In this study, we proposed a deep learning-based novel protocol using the COP signal frequencies to estimate the equilibrium score (ES), a sensory system contribution. Sensory organization test was performed with normal controls (n=125), patients with Meniere’s disease (n=72) and vestibular neuritis (n=105). The COP signals preprocessed via filtering, detrending and augmenting during quiet standing were converted to frequency domains utilizing Short-time Fourier Transform. Four different types of CNN backbone including GoogleNet, ResNet-18, SqueezeNet, and VGG16 were trained and tested using the frequency transformed data of COP and the ES under conditions #2 to #6. Additionally, the 100 original output classes (1 to 100 ESs) were encoded into 50, 20, 10 and 5 sub-classes to improve the performance of the prediction model. Absolute difference between the measured and predicted ES was about 1.7 (ResNet-18 with encoding of 20 sub-classes). The average error of each sensory analysis calculated using the measured ES and predicted ES was approximately 1.0%. The results suggest that the sensory system contribution of patients with dizziness can be quantitatively assessed using only the COP signal from a single test of standing posture. This study has potential to reduce balance testing time (spent on six conditions with three trials each in sensory organization test) and the size of computerized dynamic posturography (movable visual surround and force plate), and helps achieve the widespread application of the balance assessment.

Background: Numerous studies have indicated altered temporal features of the brain function in Parkinson's disease (PD), and the autocorrelation magnitude of intrinsic neural signals, called intrinsic neural timescales, were often applied to estimate how long neural information stored in local brain areas. However, it is unclear whether PD patients at different disease stages exhibit abnormal timescales accompanied with abnormal gray matter volume (GMV). Purpose: To assess the intrinsic timescale and GMV in PD. Study Type: Prospective. Population: 74 idiopathic PD patients (44 early stage (PD‐ES) and 30 late stage (PD‐LS), as determined by the Hoehn and Yahr (HY) severity classification scale), and 73 healthy controls (HC). Field Strength/Sequence: 3.0 T MRI scanner; magnetization prepared rapid acquisition gradient echo and echo planar imaging sequences. Assessment: The timescales were estimated by using the autocorrelation magnitude of neural signals. Voxel‐based morphometry was performed to calculate GMV in the whole brain. Severity of motor symptoms and cognitive impairments were assessed using the unified PD rating scale, the HY scale, the Montreal cognitive assessment, and the mini‐mental state examination. Statistical Test: Analysis of variance; two‐sample t‐test; Spearman rank correlation analysis; Mann–Whitney U test; Kruskal‐Wallis' H test. A P value <0.05 was considered statistically significant. Results: The PD group had significantly abnormal intrinsic timescales in the sensorimotor, visual, and cognitive‐related areas, which correlated with the symptom severity (ρ = −0.265, P = 0.022) and GMV (ρ = 0.254, P = 0.029). Compared to the HC group, the PD‐ES group had significantly longer timescales in anterior cortical regions, whereas the PD‐LS group had significantly shorter timescales in posterior cortical regions. Conclusion: This study suggested that PD patients have abnormal timescales in multisystem and distinct patterns of timescales and GMV in cerebral cortex at different disease stages. This may provide new insights for the neural substrate of PD. Level of Evidence: 2 Technical Efficacy Stage: 1 [ABSTRACT FROM AUTHOR]

The perceptual and motor coordination problems experienced following return from spaceflight reflect the sensory adaptation to altered gravity. The purpose of this study was to develop a ground-based analog that replicates similar sensorimotor impairment using a standard measures test battery and subjective feedback from experienced crewmembers. This Sensorimotor Disorientation Analog (SDA) included varying levels of sensorimotor disorientation through combined vestibular, visual, and proprioceptive disruptions. The SDA was evaluated on five previously flown astronauts to compare with their postflight experience and functional motor performance immediately (Return (R)+0 days) and +24 h (R+1) after landing. The SDA consisted of galvanic vestibular stimulation (GVS), visual disruption goggles, and a weighted suit to alter proprioceptive feedback and replicate perceived heaviness postflight. Astronauts reported that GVS alone replicated ∼50–90% of their postflight performance with the weighted suit fine-tuning the experience to replicate an additional 10%–40% of their experience. Astronauts did not report feeling that the disruption goggles represented either the visual disruptions or illusory sensations that they experienced, nor did they impact motor performance in postflight tasks similarly. Based on these results, we recommend an SDA including the GVS and the weighted suit. These results provide a more realistic and portable SDA framework to provide transient spaceflight-relevant sensorimotor disruptions for use in countermeasure testing and as a pre-flight training tool.

“Are you LISTENING?” may be one of the most frequent questions preschoolers hear from their parents and teachers, but can children be taught to listen carefully—and thus better comprehend language—and if so, what changes occur in their brains? Twenty-seven four- and five-year-old children were taught a language simulation strategy to use while listening to stories: first, they practiced moving graphics on an iPad to correspond to the story actions, and then they practiced imagining the movements. Compared to a control condition, children in the intervention answered comprehension questions more accurately when imagining moving the graphics and on a measure of transfer using a new story without any instruction and with only immovable graphics. Importantly, for children in the intervention, the change in comprehension from the first to the sixth day was strongly correlated with changes in EEG mu and alpha desynchronization, suggesting changes in motor and visual processing following the intervention. Thus, the data are consistent with our hypothesis that a language simulation listening comprehension intervention can improve children’s listening comprehension by teaching children to align visual and motor processing with language comprehension.

Pyramidal tract lesions determine the clinical syndrome of Hereditary Spastic Paraplegia (HSP). The clinical impairments of HSP are typically exemplified by their deficits in mobility, leading to falls and injuries. The first aim of this study was to identify the cause for postural abnormalities caused by pyramidal tract lesions in HSP. The second aim was to specify the effect of treadmill training for postural abnormalities. We examined nine HSP patients before and after treadmill training, as well as nine healthy control subjects during perturbed and unperturbed stance. We found that HSP was associated with larger sway amplitudes and velocities. Body excursions following platform tilts were larger, and upper body excursions showed a phase lead. Model-based analysis detected a greater time delay and a reduced long-term error correction of postural reactions in the center of mass. HSP patients performed significantly better in clinical assessments after treadmill training. In addition, treadmill training reduced sway amplitudes and body excursions, most likely by increasing positional and velocity error correction gain as a compensatorymechanism, while the time delay and long-term error correction gain remained largely unaffected. Moreover, the upper body's phase lead was reduced.We conclude that HSP leads to very specific postural impairments. While postural control generally benefits from treadmill training, the effect seems to mainly rely on compensatory mechanisms, whereas the original deficits are not affected significantly. [ABSTRACT FROM AUTHOR]

Context: Joint mobilizations have been studied extensively in the literature for the glenohumeral joint and talocrural joint (ankle). Consequently, joint mobilizations have been established as an effective means of improving range of motion (ROM) within these joints. However, there is a lack of extant research to suggest these effects may apply within another critical joint in the body, the hip. Objective: To examine the immediate effects of hip joint mobilizations on hip ROM and functional outcomes. Secondarily, this study sought to examine the efficacy of a novel hip mobilization protocol. Design: A prospective exploratory study. Setting: Two research labs. Patients or Other Participants: The study included 19 active male (n = 8) and female (n = 11) college students (20.56 [1.5] y, 171.70 [8.6] cm, 72.23 [12.9] kg). Interventions: Bilateral hip mobilizations were administered with the use of a mobilization belt. Each participant received hip joint mobilization treatments once during 3 weekly sessions followed immediately by preintervention and postintervention testing/measurements. Testing for each participant occurred once per week, at the same time of day, for 3 consecutive weeks. Hip ROM was the first week, followed by modified Star Excursion Balance Test the second week and agility T test during the third week. Main Outcomes Measures: Pretest and posttest measurements included hip ROM for hip flexion, extension, abduction, adduction, internal and external rotation, as well as scores on the modified Star Excursion Balance Test (anterior, posterolateral, and posteromedial directions) and agility T test. Results: A significant effect for time was found for hip adduction, internal and external rotation ROM, as well as the posterolateral and posteromedial directions of the modified Star Excursion Balance Test. A separate main effect for both limbs was found for adduction and internal rotation ROM. Conclusion: Isolated immediate changes in ROM and functional outcomes were evident. Further evaluation is needed. [ABSTRACT FROM AUTHOR]

Pyramidal tract lesions determine the clinical syndrome of Hereditary Spastic Paraplegia (HSP). The clinical impairments of HSP are typically exemplified by their deficits in mobility, leading to falls and injuries. The first aim of this study was to identify the cause for postural abnormalities caused by pyramidal tract lesions in HSP. The second aim was to specify the effect of treadmill training for postural abnormalities. We examined nine HSP patients before and after treadmill training, as well as nine healthy control subjects during perturbed and unperturbed stance. We found that HSP was associated with larger sway amplitudes and velocities. Body excursions following platform tilts were larger, and upper body excursions showed a phase lead. Model-based analysis detected a greater time delay and a reduced long-term error correction of postural reactions in the center of mass. HSP patients performed significantly better in clinical assessments after treadmill training. In addition, treadmill training reduced sway amplitudes and body excursions, most likely by increasing positional and velocity error correction gain as a compensatory mechanism, while the time delay and long-term error correction gain remained largely unaffected. Moreover, the upper body’s phase lead was reduced. We conclude that HSP leads to very specific postural impairments. While postural control generally benefits from treadmill training, the effect seems to mainly rely on compensatory mechanisms, whereas the original deficits are not affected significantly.

ObjectivesFatigue can decrease knee stability and increase the injury risk. However, fatigue is rarely being applied throughout movement analysis. The aim of this study was to investigate if the knee stability throughout SLDLs differ between cyclic and acyclic sports, before and after fatigue in general, and between the dominant and non-dominant leg of soccer players.MethodsA total of 43 active male (n = 34) and female (n = 9) athletes (age: 26.5 ± 7.2) participated in this study with a pre-post-design. Subjects performed a single leg drop landing (SLDL) from a plyobox. For each leg, the two-dimensional frontal plane projection angle (FPPA) was analyzed. After pretesting the shuttle run test was performed until exhaustion, before repeating the measurements.ResultsANOVA with repeated measures was applied and identified no significance difference for the FPPA between cyclic and acyclic sports (F = 0.98, p = 0.33), a significant difference before and after fatigue (F = 12.49, p = 0.002) and no significant difference between the dominant and non dominant leg of soccer players (F = 4.35, p = 0.26).DiscussionFatigue seems to be able to have a significant influence on knee stability in the frontal axis. Therefore, fatigue should be included in motion analysis for injury prevention and return to play tests because during this physical state most injuries happen.

Improvements in the speed and cost of expression profiling of neuronal tissues offer an unprecedented opportunity to define ever finer subgroups of neurons for functional studies. In the spinal cord, single cell RNA sequencing studies support decades of work on spinal cord lineage studies, offering a unique opportunity to probe adult function based on developmental lineage. While Cre/Flp recombinase intersectional strategies remain a powerful tool to manipulate spinal neurons, the field lacks genetic tools and strategies to restrict manipulations to the adult mouse spinal cord at the speed at which new tools develop. This study establishes a new workflow for intersectional mouse-viral strategies to dissect adult spinal function based on developmental lineages in a modular fashion. To restrict manipulations to the spinal cord, we generate a brain-sparing Hoxb8FlpO mouse line restricting Flp recombinase expression to caudal tissue. Recapitulating endogenous Hoxb8 gene expression, Flpdependent reporter expression is present in the caudal embryo starting day 9.5. This expression restricts Flp activity in the adult to the caudal brainstem and below. Hoxb8FlpO heterozygous and homozygous mice do not develop any of the sensory or locomotor phenotypes evident in Hoxb8 heterozygous or mutant animals, suggesting normal developmental function of the Hoxb8 gene and protein in Hoxb8FlpO mice. Compared to the variability of brain recombination in available caudal Cre and Flp lines, Hoxb8FlpO activity is not present in the brain above the caudal brainstem, independent of mouse genetic background. Lastly, we combine the Hoxb8FlpO mouse line with dorsal horn developmental lineage Cre mouse lines to express GFP in developmentally determined dorsal horn populations. Using GFP-dependent Cre recombinase viruses and Cre recombinase-dependent inhibitory chemogenetics, we target developmentally defined lineages in the adult. We show how developmental knock-out versus transient adult silencing of the same RORβ lineage neurons affects adult sensorimotor behavior. In summary, this new mouse line and viral approach provides a blueprint to dissect adult somatosensory circuit function using Cre/Flp genetic tools to target spinal cord interneurons based on genetic lineage. [ABSTRACT FROM AUTHOR]

Introduction: Human motor learning processes are a fundamental part of our daily lives and can be adversely affected by neurologic conditions. Motor learning largely depends on successfully integrating cognitive and motor-related sensory information, and a simple, easily accessible treatment that could enhance such processes would be exciting and clinically impactful. Normobaric 100% oxygen treatment (NbOxTr) is often used as a first-line intervention to improve survival rates of brain cells in neurological trauma, and recent work indicates that improvements in elements crucial for cognitive-motor-related functions can occur during NbOxTr. However, whether NbOxTr can enhance the motor learning processes of healthy human brains is unknown. Here, we investigated whether a brief NbOxTr administered via nasal cannula improves motor learning processes during a visuomotor adaptation task where participants adapt to a visual distortion between visual feedback and hand movements. Methods: 40 healthy young adults (M = 21 years) were randomly assigned to a NbOxTr (N = 20; 100% oxygen) or air (N = 20; regular air) group and went through four typical visuomotor adaptation phases (Baseline, Adaptation, After-Effect, Refresher). Gas treatment (flow rate 5 L/min) was only administered during the Adaptation phase of the visuomotor experiment, in both groups. Results: The NbOxTr provided during the Adaptation phase led to significantly faster and about 30% improved learning (p < 0.05). Notably, these motor learning improvements consolidated into the subsequent experiment phases, i.e., after the gas treatment was terminated (p < 0.05). Discussion: We conclude that this simple and brief NbOxTr dramatically improved fundamental human motor learning processes and may provide promising potential for neurorehabilitation and skill-learning approaches. Further studies should investigate whether similar improvements exist in elderly and neurologically impaired individuals, other motor learning tasks, and also longlasting effects. [ABSTRACT FROM AUTHOR]

In this article, we review recent advances in research on rhythm and musical beat perception, focusing on the role of predictive processes in auditory motor interactions. We suggest that experimental evidence of the motor system's role in beat perception, including in passive listening, may be explained by the generation and maintenance of internal predictive models, concordant with the Active Inference framework of sensory processing. We highlight two complementary hypotheses for the neural underpinnings of rhythm perception: The Action Simulation for Auditory Prediction hypothesis (Patel and Iversen, 2014) and the Gradual Audiomotor Evolution hypothesis (Merchant and Honing, 2014) and review recent experimental progress supporting each of these hypotheses. While initial formulations of ASAP and GAE explain different aspects of beat-based timing-the involvement of motor structures in the absence of movement, and physical entrainment to an auditory beat respectively-we suggest that work under both hypotheses provide converging evidence toward understanding the predictive role of the motor system in the perception of rhythm, and the specific neural mechanisms involved. We discuss future experimental work necessary to further evaluate the causal neural mechanisms underlying beat and rhythm perception.

It is well-known that sensorimotor training aims to increase the performance of the sensorimotor system to maintain an upright position. Through the use of a randomized placebo-controlled trial, the specific aim of this study was to investigate the short-term effects of a specific session of sensorimotor training on postural balance, stability and coordination in healthy, recreationally active participants. Ninety subjects were randomly allocated into three groups: experimental (n = 30), placebo (n = 32) and control (n = 28). The experimental group performed a 5 min warm-up, with the sensorimotor training consisting of 60-min specific sensorimotor exercises; the control group was not allowed to perform any sensorimotor training; the placebo group observed a video clip of an individual belonging to the experimental group performing the sensorimotor training accurately. All participants were seen three times per week for 4 weeks. Before and after the entire training, all groups of participants undertook stabilometric parameter assessment. The intervention-mediated sensorimotor training confirmed significant enhancement in the proprioceptive system. Significant improvement in the motor and/or sensory function was observed in the experimental and placebo groups. In conclusion, our findings suggest that specific sensorimotor training performed 3 days per week for 4 weeks could improve postural balance, stability and coordination in healthy individuals. [ABSTRACT FROM AUTHOR]

Improvements in the speed and cost of expression profiling of neuronal tissues offer an unprecedented opportunity to define ever finer subgroups of neurons for functional studies. In the spinal cord, single cell RNA sequencing studies support decades of work on spinal cord lineage studies, offering a unique opportunity to probe adult function based on developmental lineage. While Cre/Flp recombinase intersectional strategies remain a powerful tool to manipulate spinal neurons, the field lacks genetic tools and strategies to restrict manipulations to the adult mouse spinal cord at the speed at which new tools develop. This study establishes a new workflow for intersectional mouse-viral strategies to dissect adult spinal function based on developmental lineages in a modular fashion. To restrict manipulations to the spinal cord, we generate a brain-sparing Hoxb8FlpO mouse line restricting Flp recombinase expression to caudal tissue. Recapitulating endogenous Hoxb8 gene expression, Flp-dependent reporter expression is present in the caudal embryo starting day 9.5. This expression restricts Flp activity in the adult to the caudal brainstem and below. Hoxb8FlpO heterozygous and homozygous mice do not develop any of the sensory or locomotor phenotypes evident in Hoxb8 heterozygous or mutant animals, suggesting normal developmental function of the Hoxb8 gene and protein in Hoxb8FlpO mice. Compared to the variability of brain recombination in available caudal Cre and Flp lines, Hoxb8FlpO activity is not present in the brain above the caudal brainstem, independent of mouse genetic background. Lastly, we combine the Hoxb8FlpO mouse line with dorsal horn developmental lineage Cre mouse lines to express GFP in developmentally determined dorsal horn populations. Using GFP-dependent Cre recombinase viruses and Cre recombinase-dependent inhibitory chemogenetics, we target developmentally defined lineages in the adult. We show how developmental knock-out versus transient adult silencing of the same ROR𝛃 lineage neurons affects adult sensorimotor behavior. In summary, this new mouse line and viral approach provides a blueprint to dissect adult somatosensory circuit function using Cre/Flp genetic tools to target spinal cord interneurons based on genetic lineage.

This study aimed to compare time-to-boundary and sample entropy during a single-leg balance task between individuals with chronic ankle instability (CAI), lateral ankle sprain copers, and healthy controls. Twenty-two participants with CAI, 20 lateral ankle sprain copers, and 24 healthy controls performed a single-leg balance task during an eyes-closed condition. Participants with CAI exhibited lower time-to-boundary values compared with lateral ankle sprain copers and healthy controls. However, we did not find differences in sample entropy variables between cohorts. A decrease in time-to-boundary values in participants with CAI indicated that CAI may constrain the ability of the sensorimotor system to maintain the center of pressure within the boundaries of the base of support. However, the regularity of the center of pressure velocity time series appears not to be altered in the CAI cohort in this study. [ABSTRACT FROM AUTHOR]

Abstract Background An individual’s rapid motor skills allow them to perform many daily activities and are a hallmark of physical health. Although age and sex are both known to affect motor performance, standardized methods for assessing their impact on upper limb function are limited. Methods Here we perform a cross-sectional study of 643 healthy human participants in two interactive motor tasks developed to quantify sensorimotor abilities, Object-Hit (OH) and Object-Hit-and-Avoid (OHA). The tasks required participants to hit virtual objects with and without the presence of distractor objects. Velocities and positions of hands and objects were recorded by a robotic exoskeleton, allowing a variety of parameters to be calculated for each trial. We verified that these tasks are viable for measuring performance in healthy humans and we examined whether any of our recorded parameters were related to age or sex. Results Our analysis shows that both OH and OHA can assess rapid motor behaviours in healthy human participants. It also shows that while some parameters in these tasks decline with age, those most associated with the motor system do not. Three parameters show significant sex-related effects in OH, but these effects disappear in OHA. Conclusions This study suggests that the underlying effect of aging on rapid motor behaviours is not on the capabilities of the motor system, but on the brain’s capacity for processing inputs into motor actions. Additionally, this study provides a baseline description of healthy human performance in OH and OHA when using these tasks to investigate age-related declines in sensorimotor ability.

• Somatosensory system reorganization occurs in unilateral motor stroke. • The hemispheric shift of somatosensory processing provides feedback to post-stroke motor control. • The somatosensory system in the brain could be a new target for movement rehabilitation in stroke. Previous studies found that post-stroke motor impairments are associated with damage to the lesioned corticospinal tract and a maladaptive increase in indirect contralesional motor pathways. How the somatosensory system adapts to the change in the use of motor pathways and the role of adaptive sensory feedback to the abnormal movement control of the paretic arm remains largely unknown. We hypothesize that following a unilateral stroke, there is an adaptive hemispheric shift of somatosensory processing toward the contralesional sensorimotor areas to provide sensory feedback support to the contralesional indirect motor pathways. This research could provide new insights related to somatosensory reorganization after stroke, which could enrich future hypothesis-driven therapeutic rehabilitation strategies from a sensory or sensory-motor perspective. Understanding how somatosensory information shifts may provide a target for a novel method to therapeutically prevent and mitigate the emergence and expression of upper limb motor impairments, following a stroke. [ABSTRACT FROM AUTHOR]

There is experimental evidence that the brain systems involved in action execution also play a role in action observation and understanding. Recently, it has been suggested that the sensorimotor system is also involved in language processing. Supporting results are slower response times and weaker motorrelated MEG Beta band power suppression in semantic decision tasks on single action verbs labels when the stimulus and the motor response involve the same effector. Attenuated power suppression indicates decreased cortical excitability and consequent decreased readiness to act. The embodied approach forwards that the simultaneous involvement of the sensorimotor system in the processing of the linguistic content and in the planning of the response determines this language-motor interference effect. Here, in a combined behavioral and MEG study we investigated to what extent the processing of actions visually presented (i.e., pictures of actions) and verbally described (i.e., verbs in written words) share common neural mechanisms. The findings demonstrated that, whether an action is experienced visually or verbally, its processing engages the sensorimotor system in a comparable way. These results provide further support to the embodied view of semantic processing, suggesting that this process is independent from the modality of presentation of the stimulus, including language. [ABSTRACT FROM AUTHOR]

The cortical motor system can be reorganized following a stroke, with increased recruitment of the contralesional hemisphere. However, it is unknown whether a similar hemispheric shift occurs in the somatosensory system to adapt to this motor change, and whether this is related to movement impairments. This proof-of-concept study assessed somatosensory evoked potentials (SEPs), P50 and N100, in hemiparetic stroke participants and age-matched controls using high-density electroencephalograph (EEG) recordings during tactile finger stimulation. The laterality index was calculated to determine the hemispheric dominance of the SEP and re-confirmed with source localization. The study found that latencies of P50 and N100 were significantly delayed in stroke brains when stimulating the paretic hand. The amplitude of P50 in the contralateral (to stimulated hand) hemisphere was negatively correlated with the Fügl–Meyer upper extremity motor score in stroke. Bilateral cortical responses were detected in stroke, while only contralateral cortical responses were shown in controls, resulting in a significant difference in the laterality index. These results suggested that somatosensory reorganization after stroke involves increased recruitment of ipsilateral cortical regions, especially for the N100 SEP component. This reorganization delays the latency of somatosensory processing after a stroke. This research provided new insights related to the somatosensory reorganization after stroke, which could enrich future hypothesis-driven therapeutic rehabilitation strategies from a sensory or sensory-motor perspective. [ABSTRACT FROM AUTHOR]

To properly assess the risk induced by vestibular and sensorimotor adaptation during exploration missions, we examined how long-duration stays on the International Space Station affect functional performance after gravity transitions. Mission-critical tasks that challenge the balance and the locomotion control systems were assessed: i.e., sit-to-stand, recovery-from-fall, tandem-walk, and walk-and-turn. We assessed 19 astronauts, including 7 first-time flyers and 12 experienced flyers, before their flight, a few hours after landing, and then 1 day and 6–11 days later. Results show that adaptation to long-term weightlessness causes deficits in functional performance immediately after landing that can last for up to 1 week. No differences were observed between first-time and experienced astronaut groups. These data suggest that additional sensorimotor-based countermeasures may be necessary to maintain functional performance at preflight levels when landing on planetary surfaces after a long period in weightlessness.

Background: An individual's rapid motor skills allow them to perform many daily activities and are a hallmark of physical health. Although age and sex are both known to affect motor performance, standardized methods for assessing their impact on upper limb function are limited.Methods: Here we perform a cross-sectional study of 643 healthy human participants in two interactive motor tasks developed to quantify sensorimotor abilities, Object-Hit (OH) and Object-Hit-and-Avoid (OHA). The tasks required participants to hit virtual objects with and without the presence of distractor objects. Velocities and positions of hands and objects were recorded by a robotic exoskeleton, allowing a variety of parameters to be calculated for each trial. We verified that these tasks are viable for measuring performance in healthy humans and we examined whether any of our recorded parameters were related to age or sex.Results: Our analysis shows that both OH and OHA can assess rapid motor behaviours in healthy human participants. It also shows that while some parameters in these tasks decline with age, those most associated with the motor system do not. Three parameters show significant sex-related effects in OH, but these effects disappear in OHA.Conclusions: This study suggests that the underlying effect of aging on rapid motor behaviours is not on the capabilities of the motor system, but on the brain's capacity for processing inputs into motor actions. Additionally, this study provides a baseline description of healthy human performance in OH and OHA when using these tasks to investigate age-related declines in sensorimotor ability. [ABSTRACT FROM AUTHOR]

It is well-known that sensorimotor training aims to increase the performance of the sensorimotor system to maintain an upright position. Through the use of a randomized placebo-controlled trial, the specific aim of this study was to investigate the short-term effects of a specific session of sensorimotor training on postural balance, stability and coordination in healthy, recreationally active participants. Ninety subjects were randomly allocated into three groups: experimental (n = 30), placebo (n = 32) and control (n = 28). The experimental group performed a 5 min warm-up, with the sensorimotor training consisting of 60-min specific sensorimotor exercises; the control group was not allowed to perform any sensorimotor training; the placebo group observed a video clip of an individual belonging to the experimental group performing the sensorimotor training accurately. All participants were seen three times per week for 4 weeks. Before and after the entire training, all groups of participants undertook stabilometric parameter assessment. The intervention-mediated sensorimotor training confirmed significant enhancement in the proprioceptive system. Significant improvement in the motor and/or sensory function was observed in the experimental and placebo groups. In conclusion, our findings suggest that specific sensorimotor training performed 3 days per week for 4 weeks could improve postural balance, stability and coordination in healthy individuals.

Sense of agency refers to the experience of controlling one's actions. Studies on healthy people indicated that their self-other attribution can be realized based on prediction error which is an inconsistency between the internal prediction and sensory feedback of the movements. However, studies on patients with post-stroke sensorimotor deficits hypothesized that their self-other attribution can be based on different attribution strategies. This preliminary study examined this hypothesis by investigating whether post-stroke sensorimotor deficits can diminish the correlation between prediction errors and self-other judgments. Participants performed sinusoidal movements with visual feedback and judged if it represented their or another's movements (i.e., self-other judgment). The results indicated that the patient who had worse upper limb sensorimotor deficits and lesser paretic upper limb activity compared with the other patient made more misattributions and showed a lower correlation between prediction errors and self-other judgments. This finding suggests that post-stroke sensorimotor deficits can impair the relationship between prediction error and self-other attribution, supporting the hypothesis that patients with such deficits can have altered strategies for the registration of agency. [ABSTRACT FROM AUTHOR]

It is well‐accepted that processing observed actions involves at some extent the same neural mechanisms responsible for action execution. More recently, it has been forwarded that also the processing of verbs expressing a specific motor content is subserved by the neural mechanisms allowing individuals to perform the content expressed by that linguistic material. This view is also known as embodiment and contrasts with a more classical approach to language processing that considers it as amodal. In the present study, we used a go/no‐go paradigm, in which participants were requested to respond to real words and pictures and refrain from responding when presented stimuli were pseudowords and scrambled images. Real stimuli included pictures depicting hand‐ and foot‐related actions and verbs expressing hand‐ and foot‐related actions. We, therefore, directly compared the modulation of hand motor responses during the observation of actions and the presentation of verbs, expressing actions in the same category. The results have shown that participants gave slower hand motor responses during the observation of hand actions and the processing of hand‐related verbs as than observed foot actions and related verbs. These findings support embodiment showing that whatever the modality of presentation (observed action or verb), the modulation of hand motor responses was similar, thus suggesting that processing seen actions and related verbs shares common mechanisms most likely involving the motor system and the underlying motor experience. [ABSTRACT FROM AUTHOR]

Impaired sensorimotor circuits have been suggested in Attention-deficit/hyperactivity disorder (ADHD). NRXN1, highly expressed in cortex and cerebellum, was one of the candidate risk genes for ADHD, while its effects on sensorimotor circuits are unclear. In this content, we aimed to investigate the differential brain effects as functions of the cumulative genetic effects of NRXN1 variants in ADHD and healthy controls (HCs), identifying a potential pathway mapping from NRXN1, sensorimotor circuits, to ADHD. Magnetic resonance imaging, blood samples and clinical assessments were acquired from 53 male ADHD and 46 sex-matched HCs simultaneously. The effects of the cumulative genetic effects of NRXN1 variants valued by poly-variant risk score (PRS), on brain function was measured by resting-state functional connectivity (rs-FC) of cerebrocerebellar circuits. Mediation analyses were conducted to evaluate the association between NRXN1, functional abnormality, and ADHD diagnosis, as well as ADHD symptoms. The results were validated by bootstrapping and 10,000 times permutation tests. The rs-FC analyses demonstrated significant mediation models for ADHD diagnosis, and emphasized the involvement of cerebellum, middle cingulate gyrus and temporal gyrus, which are crucial parts of sensorimotor circuits. The current study suggested NRXN1 conferred risk for ADHD by regulating the function of sensorimotor circuits. [ABSTRACT FROM AUTHOR]

A broad sketch for a model of speech production is outlined which describes developmental aspects of its cognitive-linguistic and sensorimotor components. A description of the emergence of phonological knowledge is a central point in our model sketch. It will be shown that the phonological form level emerges during speech acquisition and becomes an important representation at the interface between cognitive-linguistic and sensorimotor processes. Motor planning as well as motor programming are defined as separate processes in our model sketch and it will be shown that both processes revert to the phonological information. Two computational simulation experiments based on quantitative implementations (simulation models) are undertaken to show proof of principle of key ideas of the model sketch: (i) the emergence of phonological information over developmental stages, (ii) the adaptation process for generating new motor programs, and (iii) the importance of various forms of phonological representation in that process. Based on the ideas developed within our sketch of a production model and its quantitative spell-out within the simulation models, motor planning can be defined here as the process of identifying a succession of executable chunks from a currently activated phoneme sequence and of coding them as raw gesture scores. Motor programming can be defined as the process of building up the complete set of motor commands by specifying all gestures in detail (fully specified gesture score including temporal relations). This full specification of gesture scores is achieved in our model by adapting motor information from phonologically similar syllables (adapting approach) or by assembling motor programs from sub-syllabic units (assembling approach). [ABSTRACT FROM AUTHOR]

Background: Patients with shoulder pain may have proprioceptive and balance deficits. However, studies on balance in patients with shoulder pain are scarce. Objective: This study aims to investigate if patients with chronic shoulder pain demonstrate deficits in standing and walking balance and to study the relationship between outcome measures of balance and age and body mass index (BMI). Materials and Methods: This case–control study was conducted at Dammam Medical Complex, Dammam, Saudi Arabia, between March and November 2018. The study recruited patients (n = 15) with chronic shoulder pain (>4 months) and healthy controls (n = 15) matched for age, gender and BMI. Standing balance was tested using a Challenge Disc test, the Romberg test and timed unipedal stance test (UPST). Walking balance was assessed using the timed up and go (TUG) test, stance phase duration and center of pressure (COP) deviation. Independent t-tests were used to investigate the differences between the two groups in demographic data and all the outcome measurements. Pearson correlation coefficients were used for correlation analysis. Results: No statistically significant differences were found between the two groups in any outcome of the standing balance (P ≥ 0.095) or walking balance (P ≥ 0.160). However, medium effect sizes were found for the UPST (η2: ≥0.06), Challenge Disc (η2: 0.06), TUG (Cohen's d: 0.54) and COP deviation (Cohen's d: 0.53). There was a moderate correlation between BMI and Challenge Disc (P = 0.025) and between age and Challenge Disc (P = 0.012) in both the groups. Conclusion: Patients with chronic shoulder pain had lower balance measurements compared with healthy people, although this difference was not statistically significant.

A broad sketch for a model of speech production is outlined which describes developmental aspects of its cognitive-linguistic and sensorimotor components. A description of the emergence of phonological knowledge is a central point in our model sketch. It will be shown that the phonological form level emerges during speech acquisition and becomes an important representation at the interface between cognitive-linguistic and sensorimotor processes. Motor planning as well as motor programming are defined as separate processes in our model sketch and it will be shown that both processes revert to the phonological information. Two computational simulation experiments based on quantitative implementations (simulation models) are undertaken to show proof of principle of key ideas of the model sketch: (i) the emergence of phonological information over developmental stages, (ii) the adaptation process for generating new motor programs, and (iii) the importance of various forms of phonological representation in that process. Based on the ideas developed within our sketch of a production model and its quantitative spell-out within the simulation models, motor planning can be defined here as the process of identifying a succession of executable chunks from a currently activated phoneme sequence and of coding them as raw gesture scores. Motor programming can be defined as the process of building up the complete set of motor commands by specifying all gestures in detail (fully specified gesture score including temporal relations). This full specification of gesture scores is achieved in our model by adapting motor information from phonologically similar syllables (adapting approach) or by assembling motor programs from sub-syllabic units (assembling approach).

Individuals with chronic ankle instability (CAI) are believed to rely more on visual information during postural control due to impaired proprioceptive function, which may increase the risk of injury when their vision is limited during sports activities. Objectives: To compare (1) the effects of balance training with and without stroboscopic glasses on postural control and (2) the effects of the training on visual reliance in patients with CAI. Design: A randomized controlled clinical trial. Methods: Twenty‐eight CAI patients were equally assigned to one of 2 groups: strobe or control group. The strobe group wore stroboscopic glasses during a 4‐week balance training. Static postural control, a single‐leg hop balance test calculated by Dynamic Postural Stability Index (DPSI), and the Y‐Balance test (YBT) were measured. During the tests, there were different visual conditions: eyes‐open (EO), eyes‐closed (EC), and strobe vision (SV). Romberg ratios were then calculated as SV/EO, and EC/EO and used for statistical analysis. Results: The strobe group showed a higher pretest‐posttest difference in velocity in the medial‐lateral direction and vertical stability index under SV compared with the control group (p <.05). The strobe group showed higher differences in EC/EO for velocity in the medial‐lateral and anterior‐posterior directions, and 95% confidence ellipse area (p <.05), and in SV/EO for velocity in the medial‐lateral, 95% confidence ellipse area, and YBT‐anterior direction (p <.05). Conclusion: The 4‐week balance training with stroboscopic glasses appeared to be effective in improving postural control and altering visual reliance in patients with CAI. [ABSTRACT FROM AUTHOR]

The human cognitive map formation is still an open question. Based on biological facts, the cognitive map origin goes back to the age of the fetus human. In this paper, our aim is to provide a possible answer to that question. Accordingly, we present a theoretical model of the development of the cognitive map of a fetus human using its sensorimotor data. We define positions of the cognitive map as associations between high-level perceptions created from different sensory sources. We use a proposed method referred to as Frequency-based-means clustering algorithm to develop the perceptions that form the association map. Our proposed theoretical model is tested on simulated data. Results show that our model is a possible candidate for demonstrating how the cognitive map is formed. In addition, comparison with k-means clustering is presented and results show that the frequency-based-means clustering has a better performance than k-means clustering and is more suitable for this application.

The author of the article has summarised his experience with the rehabilitation of combined speech and swallowing disorders in the oropharyngeal area in adults. The essence of the described therapeutic procedures is the use of the sensorimotor and physiological muscle contraction of the upper limb and muscles of the oropharyngeal region. This rehabilitative procedure allows for the whole motoric pattern (swallowing, articulation) to be worked with, and not merely its parts. The efficiency and specifics of these treatment techniques are documented in individual case reports. The author of the article is the originator of this technique.

The review considers the current ideas about the role of the gravitational factor in activities of the sensorimotor and cardiovascular systems, as well as new basic problems and questions of space medicine and physiology. The review presents data on animal embryonic development in weightlessness, evolution of the motor and cardiovascular systems, and characteristics of their functions in conditions of normal and altered gravity. Much attention is paid to the results of unique studies with ground-based gravitational unloading models: head-down bed rest, dry immersion and hindlimb suspension, in which the mechanisms that regulate various body systems under conditions of altered gravity were studied. Terrestrial organisms have learned to live in the gravitational field. Almost all of their body systems are gravity dependent. However, the extent and mechanisms of this dependence remained unclear for a long time. Space flights opened up the possibility of studying the activity of living systems in the absence of gravity. Changes in activity of sensory systems are among the main factors that mediate the effect of weightlessness on the motor system. Under the Earth's conditions, the afferent support of motor control is polyreceptive and involves vision, the vestibular apparatus, and support and muscular proprioception. In microgravity, activity of some channels is completely eliminated (support afferentation), distorted (vestibular apparatus), or weakened (proprioception). Similar processes occur in the cardiovascular system: loss of the gravity-dependent pressure gradient causes profound changes in the structure and function of the heart and vessels, including both resistive and capacitive ones. It is still an open question as to how much the various changes occurring in the cardiovascular system are associated with the disappearance of the gravity-dependent pressure gradient. Some questions of gravitational physiology are impossible to answer in space flights experiments. Various methods were therefore developed to simulate the effects of gravitational unloading on the Earth. New knowledge on the mechanisms of changes occurring in the sensorimotor system was gotten by comparing space flight data and data obtained in model experiments. A basic problem of gravitational physiology of the cardiovascular system is the degree of correspondence between changes observed in laboratory animals or under model conditions (bed rest, immersion, and hindlimb suspension) and changes recorded in humans during real space flights. The problem is specially discussed in the review. Many issues remain unresolved in the light of future inter-planetary missions, including the problems of post-flight readaptation of the motor and cardiovascular systems to normal gravity conditions. Another problem is preventing losses of strength, endurance, and orthostatic stability. The development and improvement of countermeasures for preventing the negative effects of space flight is impossible without understanding the mechanisms that underlie the observed changes. [ABSTRACT FROM AUTHOR]

Heightened reliance on the cerebral cortex for postural stability with aging is well-known, yet the cortical mechanisms for balance control, particularly in relation to balance function, remain unclear. Here we aimed to investigate motor cortical activity in relation to the level of balance challenge presented during reactive balance recovery and identify circuit-specific interactions between motor cortex and prefrontal or somatosensory regions in relation to metrics of balance function that predict fall risk. Using electroencephalography, we assessed motor cortical beta power, and beta coherence during balance reactions to perturbations in older adults. We found that individuals with greater motor cortical beta power evoked following standing balance perturbations demonstrated lower general clinical balance function. Individual older adults demonstrated a wide range of cortical responses during balance reactions at the same perturbation magnitude, showing no group-level change in prefrontal- or somatosensory-motor coherence in response to perturbations. However, older adults with the highest prefrontal-motor coherence during the post-perturbation, but not pre-perturbation, period showed greater cognitive dual-task interference (DTI) and elicited stepping reactions at lower perturbation magnitudes. Our results support motor cortical beta activity as a potential biomarker for individual level of balance challenge and implicate prefrontal-motor cortical networks in distinct aspects of balance control involving response inhibition of reactive stepping in older adults. Cortical network activity during balance may provide a neural target for precision-medicine efforts aimed at fall prevention with aging.

Heightened reliance on the cerebral cortex for postural stability with aging is well-known, yet the cortical mechanisms for balance control, particularly in relation to balance function, remain unclear. Here we aimed to investigate motor cortical activity in relation to the level of balance challenge presented during reactive balance recovery and identify circuit-specific interactions between motor cortex and prefrontal or somatosensory regions in relation to metrics of balance function that predict fall risk. Using electroencephalography, we assessed motor cortical beta power, and beta coherence during balance reactions to perturbations in older adults. We found that individuals with greater motor cortical beta power evoked following standing balance perturbations demonstrated lower general clinical balance function. Individual older adults demonstrated a wide range of cortical responses during balance reactions at the same perturbation magnitude, showing no group-level change in prefrontal- or somatosensory-motor coherence in response to perturbations. However, older adults with the highest prefrontal-motor coherence during the post-perturbation, but not pre-perturbation, period showed greater cognitive dual-task interference (DTI) and elicited stepping reactions at lower perturbation magnitudes. Our results support motor cortical beta activity as a potential biomarker for individual level of balance challenge and implicate prefrontal-motor cortical networks in distinct aspects of balance control involving response inhibition of reactive stepping in older adults. Cortical network activity during balance may provide a neural target for precision-medicine efforts aimed at fall prevention with aging. [ABSTRACT FROM AUTHOR]

Abstract concepts can be represented in the brain by means of metaphors. Generation refers to seniority in the family or clan, implies the implementation of different attitudes required by kinship, and contains profound psychological, emotional, and social factors. Generation as an abstract concept is related to concepts such as power, social status, importance, and time. The conceptual metaphor theory based on the embodied theory proposes that abstract concepts are represented by actual sensorimotor experiences. Generation implied in Han kin terms is often represented by multiple spatial terms. According to conceptual metaphor theory, the current study predicted that generation could be represented by multiple spatial metaphors. We designed six experiments to investigate this issue. The results showed that (1) the up–down and left–right positions in which kinship words were presented affected the processing of the concept of generation; (2) the processing of kinship words also affected up–down and left–right spatial information perception; and (3) the processing of the concept of generation could also automatically activate the front–back spatial operation and induce the embodied simulation of body movement. In sum, the results suggested that generation might be represented by the three-dimensional spatial metaphor of vertical, horizontal, and sagittal axes, which are influenced by the sensorimotor system.