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Cognitive flexibility, the ability to switch between mental processes to generate appropriate behavioral responses, is reduced with typical aging. Previous studies have found that age‐related declines in cognitive flexibility are often accompanied by variations in the activation of multiple regions. However, no meta‐analyses have examined the relationship between cognitive flexibility in aging and age‐related variations in activation within large‐scale networks. Here, we conducted a meta‐analysis employing multilevel kernel density analysis to identify regions with different activity patterns between age groups, and determined how these regions fall into functional networks. We also employed lateralization analysis to explore the spatial distribution of regions exhibiting group differences in activation. The permutation tests based on Monte Carlo simulation were used to determine the significance of the activation and lateralization results. The results showed that cognitive flexibility in aging was associated with both decreased and increased activation in several functional networks. Compared to young adults, older adults exhibited increased activation in the default mode, dorsal attention, ventral attention, and somatomotor networks, while displayed decreased activation in the visual network. Moreover, we found a global‐level left lateralization for regions with decreased activation, but no lateralization for regions with higher activation in older adults. At the network level, the regions with decreased activation were left‐lateralized, while the regions with increased activation showed varying lateralization patterns within different networks. To sum up, we found that networks that support various mental functions contribute to age‐related variations in cognitive flexibility. Additionally, the aging brain exhibited network‐dependent activation and lateralization patterns in response to tasks involving cognitive flexibility. We highlighted that the comprehensive meta‐analysis in this study offered new insights into understanding cognitive flexibility in aging from a network perspective. [ABSTRACT FROM AUTHOR]

Background Objectives Methods Results Conclusions A randomized trial suggested that reducing left‐sided subthalamic stimulation amplitude could improve axial dysfunction.To explore open‐label tolerability and associations between trial outcomes and asymmetry data.We collected adverse events in trial participants treated with open‐label lateralized settings for ≥3 months. We explored associations between trial outcomes, location of stimulation and motor asymmetry.14/17 participants tolerated unilateral amplitude reduction (left‐sided = 10, right‐sided = 4). Two hundred eighty‐four left‐sided and 1113 right‐sided stimulated voxels were associated with faster gait velocity, 81 left‐sided and 22 right‐sided stimulated voxels were associated with slower gait velocity. Amplitude reduction contralateral to shorter step length was associated with 2.4‐point reduction in axial MDS‐UPDRS. Reduction contralateral to longer step length was associated with 10‐point increase in MDS‐UPDRS.Left‐sided amplitude reduction is potentially more tolerable than right‐sided amplitude reduction. Right‐sided more than left‐sided stimulation could be associated with faster gait velocity. Shortened step length might reflect contralateral overstimulation. [ABSTRACT FROM AUTHOR]

Elephants are known for strongly lateralized trunk behaviors, but the mechanisms driving elephant lateralization are poorly understood. Here, we investigate features of elephant mouth organization that presumably promote lateralization. We find the lower jaw of elephants is of narrow width, but is rostrally strongly elongated even beyond the jaw bone. Elephant lip vibrissae become progressively longer rostrally. Thus, elephants have two lateral dense, short microvibrissae arrays and central, less dense long macrovibrissae. This is an inversion of the ancestral mammalian facial vibrissae pattern, where central, dense short microvibrissae are flanked by two lateral macrovibrissae arrays. Elephant microvibrissae have smaller follicles than macrovibrissae. Similar to trunk‐tip vibrissae, elephant lip microvibrissae show laterally asymmetric abrasion. Observations on Asian zoo elephants indicate lateralized abrasion results from lateralized feeding. It appears that the ancestral mammalian mouth (upper and lower lips, incisors, frontal microvibrissae) is shaped by oral food apprehension. The elephant mouth organization radically changed, however, because trunk‐mediated feeding replaced oral apprehension. Such elephant mouth changes include the upper lip–nose fusion to the trunk, the super‐flexible elongated lower jaw, the loss of incisors, and lateral rather than frontal microvibrissae. Elephants' specialization for lateral food insertion is reflected by the reduction in the centering effects of oral food apprehension and lip vibrissae patterns. [ABSTRACT FROM AUTHOR]

Background: The volumes of the hippocampal subfields are related to poststroke cognitive dysfunctions. However, it remains unclear whether contralesional hippocampal subfield volume contributes to cognitive impairment. This study aimed to investigate the volumetric differences in the contralesional hippocampal subfields between patients with left and right hemisphere strokes (LHS/RHS). Additionally, correlations between contralesional hippocampal subfield volumes and clinical outcomes were explored. Methods: Fourteen LHS (13 males, 52.57 ± 7.10 years), 13 RHS (11 males, 51.23 ± 15.23 years), and 18 healthy controls (11 males, 46.94 ± 12.74 years) were enrolled. Contralesional global and regional hippocampal volumes were obtained with T1‐weighted images. Correlations between contralesional hippocampal subfield volumes and clinical outcomes, including the Montreal Cognitive Assessment (MoCA) and Mini‐Mental State Examination (MMSE), were analyzed. Bonferroni correction was applied for multiple comparisons. Results: Significant reductions were found in contralesional hippocampal as a whole (adjusted p =.011) and its subfield volumes, including the hippocampal tail (adjusted p =.005), cornu ammonis 1 (CA1) (adjusted p =.002), molecular layer (ML) (adjusted p =.004), granule cell and ML of the dentate gyrus (GC‐ML‐DG) (adjusted p =.015), CA3 (adjusted p =.009), and CA4 (adjusted p =.014) in the RHS group compared to the LHS group. MoCA and MMSE had positive correlations with volumes of contralesional hippocampal tail (p =.015, r =.771; p =.017, r =.763) and fimbria (p =.020, r =.750; p =.019, r =.753) in the LHS group, and CA3 (p =.007, r =.857; p =.009, r =.838) in the RHS group, respectively. Conclusion: Unilateral stroke caused volumetric differences in different hippocampal subfields contralesionally, which correlated to cognitive impairment. RHS leads to greater volumetric reduction in the whole contralesional hippocampus and specific subfields (hippocampal tail, CA1, ML, GC‐ML‐DG, CA3, and CA4) compared to LHS. These changes are correlated with cognitive impairments, potentially due to disrupted neural pathways and interhemispheric communication. [ABSTRACT FROM AUTHOR]

Focal damage due to stroke causes widespread abnormal changes in brain function and hemispheric asymmetry. In this study, functional near‐infrared spectroscopy (fNIRS) was used to collect resting‐state hemoglobin data from 85 patients with subacute stroke and 26 healthy controls, to comparatively analyze the characteristics of lateralization after stroke in terms of cortical activity, functional networks, and hemodynamic lags. Higher intensity of motor cortical activity, lower hemispheric autonomy, and more abnormal hemodynamic leads or lags were found in the affected hemisphere. Lateralization metrics of the three aspects were all associated with the Fugl‐Meyer score. The results of this study prove that three lateralization metrics may provide clinical reference for stroke rehabilitation. Meanwhile, the present study piloted the use of resting‐state fNIRS for analyzing hemodynamic lag, demonstrating the potential of fNIRS to assess hemodynamic abnormalities in addition to the study of cortical neurological function after stroke. [ABSTRACT FROM AUTHOR]

Objectives: This study characterizes sexual dimorphism in skeletal markers of upper limb mechanical loading due to lateralization as evidence of division of labor in medieval Giecz, Poland. Methods: Twenty‐six dimensions for paired humeri, clavicles, and radii representing adult males (n = 89) and females (n = 53) were collected from a skeletal sample from the cemetery site Gz4. Percent directional asymmetry (DA) and absolute asymmetry (AA) for each dimension were compared among bones, osteometric subcategories, and sex. Additionally, side bias and sex differences were assessed in degenerative joint disease (DJD) and entheseal changes (ECs). Results: Nearly all measurements revealed significant asymmetry favoring the right side. Asymmetry was most pronounced in midshaft dimensions with few sex differences. There were more correlations among dimensions within elements than between elements, mainly in the midshaft. No laterality in DJD frequencies was noted for either sex, but females demonstrated significantly lower odds of having DJD than males in most joints. Most ECs demonstrated a right‐bias and association with DA with no sex‐specific patterns except the biceps brachii insertion, where females were ~5 times more likely to be scored "right" than males. Discussion: The general lack of sex differences in asymmetry and ECs suggests similarly demanding workloads for females and males, with the exception of sex‐specific functional loading differences in the forearm. Further, DJD data suggest males engaged in more intensive activities involving the upper limb. These results enhance understanding of workload in this important historical period and provide a comparison for asymmetry in past populations. [ABSTRACT FROM AUTHOR]

Objective: Glottic airway stenosis (GAWS) may result from bilateral paralysis (BVFP) or posterior glottic stenosis (PGS). Since the glottis is the principal airway sphincter, surgeons shift on the balance between airway, aspirations, and voice. We aim to describe our surgical technique and outcome of the SMALS procedure for GAWS correction. Methods: A retrospective cohort of patients who underwent SMALS for PGS between 2018 and 2021. SMALS involves: endoscopic submucosal subtotal arytenoidectmy (preserving medial mucosal flap) and lateralization sutures. The sutures lateralize the mucosal flap to cover the arytenoidectomy bed without lateralization of the membranous vocal fold; expanding the posterior glottis, while preserving a relatively good voice. Covering the arytenoidectomy bed enhances healing. Medical and surgical data, airway, voice, and swallowing symptoms were collected. Relative glottic opening area (RGOA) and relative glottic insufficiency area (RGIA) were calculated. Results: Eleven PGS patients who underwent 15 SMALS were included (4 bilateral), all patients had post‐intubation PGS, 1 patient also had prior radiation to the larynx. All patients were tracheostomy‐dependent. There were no major complications. No granulation or retracting scar was observed at follow‐up. None had a persistent voice or swallowing disability. Successful outcome (decannulation) was achieved in 8 (73%); RGOA increased in all (Δ = 0.37; p = 0.003), while RGIA remained relatively stable (Δ = 0.02; p = 0.055). Conclusions: SMALS is a safe and effective, novel modification of the classic arytenoidectomy, for GAWS correction that can be easily applied and may expand the airway without significant glottic insufficiency symptoms. Level of Evidence: 4 Laryngoscope, 134:353–360, 2024 [ABSTRACT FROM AUTHOR]

Diffuse correlation spectroscopy (DCS) was used to measure resting‐state cerebral blood flow (CBF) in temporal lobes of children with autism spectrum disorder (ASD) and typically developing (TD) children. Twenty‐two children with ASD and 34 age‐matched TD children were recruited to participate in the experiment. DCS signals were recorded with 3 long source‐detector (SD) channels (SD distance = 22.0 mm) and 1 short SD channel (SD distance = 10.5 mm) from each side of the temporal lobe. Significant difference in CBF between left and right hemispheres was observed in ASD group, but not in TD group. With the degree of CBF lateralization as a discrimination feature, a leave‐one‐out ROC curve was plotted with the area‐under‐curve (AUC) value of 0.731 ± 0.010, indicating children with ASD could be discriminated from TD children. This suggested CBF lateralization in temporal lobes measured with DCS might serve as a discriminative feature for ASD. [ABSTRACT FROM AUTHOR]

Objective: To compare the operation times, graft survival and success rates, audiometric outcomes, and complications of patients who underwent transperforation myringoplasty with and without packing but without perforation rimming. Study Design: A prospective, randomized controlled trial. Setting: A university‐affiliated teaching hospital. Methods: We conducted a randomized controlled trial that enrolled patients who underwent underlay myringoplasty. No patient underwent perforation rimming. Patients underwent myringoplasty with or without graft lateral packing. The operation times, graft survival and success rates, audiometric outcomes, and complications were compared between the 2 groups. Results: Sixty patients with unilateral perforations were included. The mean neovascularization score at postoperative week 2 was significantly higher in the no‐packing group than in the packing group (p <.01) but did not differ significantly at postoperative weeks 3 and 4, or postoperative month 3. Neither the graft healing rate (p =.313) nor the perforation closure rate (p =.640) significantly differed between the 2 groups. The mean air‐bone gap improved by 8.91 ± 5.45 dB in the packing group and 8.17 ± 1.19 dB in the no‐packing group (p =.758). Conclusion: The long‐term graft success and hearing improvements in transperforation myringoplasty with no rimming of the perforation and no‐graft lateral packing were comparable to those in the graft lateral packing group with no rimming of the perforation, with a low incidence of complications. These results may change the traditional practice of packing the external auditory canal and rimming the perforation in underlay myringoplasty, even for all myringoplasty surgery. [ABSTRACT FROM AUTHOR]

The prevailing view in human cognitive neuroscience associates the medial temporal lobes (MTLs) with declarative memory. Compelling experimental evidence has, however, demonstrated that these regions are specialized according to the representations processed, irrespective of the cognitive domain assessed. This account was supported by the study of patients with bilateral medial temporal amnesia, who exhibit impairments in perceptual tasks involving complex visual stimuli. Yet, little is known regarding the impact of unilateral MTL damage on complex visual abilities. To address this issue, we administered a visual matching task to 20 patients who underwent left (N = 12) or right (N = 8) anterior temporal lobectomy for drug‐resistant epilepsy and to 38 healthy controls. Presentation viewpoint was manipulated to increase feature ambiguity, as this is critical to reveal impairments in perceptual tasks. Similar to control participants, patients with left‐sided damage succeeded in all task conditions. In contrast, patients with right‐sided damage had decreased accuracy compared with that of the other two groups, as well as increased response time. Notably, the accuracy of those with right‐sided damage did not exceed chance level when feature ambiguity was high (i.e., when stimuli were presented from different viewpoints) for the most complex classes of stimuli (i.e., scenes and buildings, compared with single objects). The pattern reported in bilateral patients in previous studies was therefore reproduced in patients with right, but not left, resection. These results suggest that the complex visual‐representation functions supported by the MTL are right‐lateralized, and raise the question as to how the representational account of these regions applies to representations supported by left MTL regions. [ABSTRACT FROM AUTHOR]

Developmental lateralization of brain function is imperative for behavioral specialization, yet few studies have investigated differences between hemispheres in structural connectivity patterns, especially over the course of development. The present study compares the lateralization of structural connectivity patterns, or topology, across children, adolescents, and young adults. We applied a graph theory approach to quantify key topological metrics in each hemisphere including efficiency of information transfer between regions (global efficiency), clustering of connections between regions (clustering coefficient [CC]), presence of hub‐nodes (betweenness centrality [BC]), and connectivity between nodes of high and low complexity (hierarchical complexity [HC]) and investigated changes in these metrics during development. Further, we investigated BC and CC in seven functionally defined networks. Our cross‐sectional study consisted of 211 participants between the ages of 6 and 21 years with 93% being right‐handed and 51% female. Global efficiency, HC, and CC demonstrated a leftward lateralization, compared to a rightward lateralization of BC. The sensorimotor, default mode, salience, and language networks showed a leftward asymmetry of CC. BC was only lateralized in the salience (right lateralized) and dorsal attention (left lateralized) networks. Only a small number of metrics were associated with age, suggesting that topological organization may stay relatively constant throughout school‐age development, despite known underlying changes in white matter properties. Unlike many other imaging biomarkers of brain development, our study suggests topological lateralization is consistent across age, highlighting potential nonlinear mechanisms underlying developmental specialization. [ABSTRACT FROM AUTHOR]

Temporal lobe epilepsy (TLE) is one of the most common subtypes of focal epilepsy, with mesial temporal sclerosis (MTS) being a common radiological and histopathological finding. Accurate identification of MTS during presurgical evaluation confers an increased chance of good surgical outcome. Here we propose the use of glutamate‐weighted chemical exchange saturation transfer (GluCEST) magnetic resonance imaging (MRI) at 7 Tesla for mapping hippocampal glutamate distribution in epilepsy, allowing to differentiate lesional from non‐lesional mesial TLE. We demonstrate that a directional asymmetry index, which quantifies the relative difference between GluCEST contrast in hippocampi ipsilateral and contralateral to the seizure onset zone, can differentiate between sclerotic and non‐sclerotic hippocampi, even in instances where traditional presurgical MRI assessments did not provide evidence of sclerosis. Overall, our results suggest that hippocampal glutamate mapping through GluCEST imaging is a valuable addition to the presurgical epilepsy evaluation toolbox. [ABSTRACT FROM AUTHOR]

Songbirds and toothed whales are able to produce different sounds with the left and right part of their sonic organs, a phenomenon termed lateralized sound production. In fishes this phenomenon is poorly known, with lateralization having been observed solely in the channel catfish (Ictalurus punctatus). They produce more sounds with their right pectoral fins. Croaking gouramis Trichopsis vittata beat their pectoral fins alternately, resulting in a series of two‐pulsed sound bursts termed croaking sounds. This study investigates lateralized sound production by comparing temporal and amplitude characteristics of sound bursts generated by pectoral fins in T. vittata. Croaking sounds, produced during dyadic contests, were analyzed in 19 females. We investigated the following characteristics of sound bursts: burst period, pulse period within bursts, the relative peak‐to‐peak amplitudes of bursts, and the ratio of peak‐to‐peak amplitudes of the first and second pulse within bursts. Sound bursts produced by the right and left sonic organ differed in 17 out of 19 females in at least one to four measured sound characteristics. The number of females whose temporal characteristics differed between pectoral fins was significantly higher than the number of females lacking such differences (16 out of 19). This was not the case for amplitude characteristics. Our data demonstrated that the sound characteristics produced by the left and right sonic organ in T. vittata differed significantly in most specimens. These differences in sound properties may constitute a new form of lateralized sound production in vocal fishes. Research Highlights: Sounds produced by the left and right pectoral fin in croaking gouramis differintemporal sound characteristics.Differences between sounds particularly involved temporal sound properties.Croaking sounds generated by left and right sonic organs may constitute a new form of lateralized sound production in animals. [ABSTRACT FROM AUTHOR]

Dentate gyrus (DG) is important for pattern separation and spatial memory, and it is thought to gate information flow to the downstream hippocampal subregions. Dentate spikes (DSs) are high‐amplitude, fast, positive local‐field potential events taking place in the DG during immobility and sleep, and they have been connected to memory consolidation in rodents. DSs are a result of signaling from the entorhinal cortex (EC) to the DG, and they suppress firing of pyramidal cells in the CA3 and CA1. To study the effects of DSs to signaling in the hippocampal tri‐synaptic loop, we electrically stimulated the afferent fibers of the DG, CA3, and CA1 in adult male Sprague–Dawley rats at different delays from DSs. Responses to stimulation were increased in the EC‐DG synapse during DSs, and the effect was amplified after theta‐burst stimulation. We concluded that DSs strengthen the excitatory signal from the EC to the DG, which is reinforced by synapse potentiation and increased excitability of granule cells after theta‐burst stimulation. This signal boosting may function in enhancing plastic changes in the DG‐CA3 synapse. As responses in the CA3 and CA1 remained unaffected by the DS, the DS‐contingent silencing of pyramidal cells seems to be a result of a decrease in excitatory input rather than a decrease in the excitability of the pyramidal cells themselves. In addition, we found that the DSs occur asynchronously in the left and right hippocampi, giving novel evidence of lateralization of the rodent hippocampus. [ABSTRACT FROM AUTHOR]

The corpus callosum (CC) is the largest fiber tract in the human brain, allowing interhemispheric communication by connecting homologous areas of the two cerebral hemispheres. In adults, CC size shows a robust allometric relationship with brain size, with larger brains having larger callosa, but smaller brains having larger callosa relative to brain size. Such an allometric relationship has been shown in both males and females, with no significant difference between the sexes. But there is some evidence that there are alterations in these allometric relationships during development. However, it is currently not known whether there is sexual dimorphism in these allometric relationships from birth, or if it only develops later. We study this in neonate data. Our results indicate that there are already sex differences in these allometric relationships in neonates: male neonates show the adult‐like allometric relationship between CC size and brain size; however female neonates show a significantly more positive allometry between CC size and brain size than either male neonates or female adults. The underlying cause of this sexual dimorphism is unclear; but the existence of this sexual dimorphism in neonates suggests that sex‐differences in lateralization have prenatal origins. [ABSTRACT FROM AUTHOR]

Faces and their aesthetic appreciation are a core element of social interaction. Although studies have been made on facial processing when looking at faces with different perspectives, a direct comparison of faces in the left to the right perspective is missing. Portraits in classical Western art indicate a preference of the left compared to the right perspective, but the neural underpinnings of such an asymmetry still have to be clarified. Using functional magnetic resonance imaging, the current study focuses on the processing of three-quarter faces seen with different perspectives. Seventeen participants were asked to passively look at photographs of six male and six female faces with a neutral expression; the photographs were taken from the left, right, and frontal perspectives while keeping their focus on the eyes. The results showed that specific brain areas were involved in processing the three-quarter faces in either symmetric or asymmetric ways. Viewing left and right three-quarter faces resulted in two mirror-like activations in the striate cortex corresponding to the symmetric layout of the left and right perspectives. Viewing the left face resulted additionally in an enhanced activation also in the left extrastriate cortex. The right perspective of male faces elicited a lower activation compared to other perspectives in face-selective areas of the brain. Our findings suggest that the preference of the left three-quarter face emerges already in the early visual pathway presumably prior to facial identification, emotional processing, and aesthetic appreciation. Our observations may have general importance in disentangling different neural components and processing stages in the spatiotemporal characteristics of artistic expressions. [ABSTRACT FROM AUTHOR]

Objective: Reorganization of the language network from typically left‐lateralized frontotemporal regions to bilaterally distributed or right‐lateralized networks occurs in anywhere from 25%–30% of patients with focal epilepsy. In patients who have been recently diagnosed with epilepsy, an important question remains as to whether it is the presence of seizures or the underlying epilepsy etiology that leads to atypical language representations. This question becomes even more interesting in pediatric samples, where the typical developmental processes of the language network may confer more variability and plasticity in the language network. We assessed a carefully selected cohort of children with recent‐onset epilepsy to examine whether it is the effects of seizures or their underlying cause that leads to atypical language lateralization. Methods: We used functional magnetic resonance imaging (fMRI) to compare language laterality in children with recently diagnosed focal unaware epilepsy and age‐matched controls. Age at epilepsy onset (age 4 to 6 years vs age 7 to 12 years) was also examined to determine if age at onset influenced laterality. Results: The majority of recent‐onset patients and controls exhibited left‐lateralized language. There was a significant interaction such that the relationship between epilepsy duration and laterality differed by age at onset. In children with onset after age 6, a longer duration of epilepsy was associated with less left‐lateralized language dominance. In contrast, in children with onset between 4 and 6 years of age, a longer duration of epilepsy was not associated with less left language dominance. Significance: Our results demonstrate that although language remained largely left‐lateralized in children recently diagnosed with epilepsy, the impact of seizure duration depended on age at onset, indicating that the timing of developmental and disease factors are important in determining language dominance. [ABSTRACT FROM AUTHOR]

Purpose: To determine the reliability of anatomic references for mediolateral component positioning in shoulder arthroplasty. Materials and methods: The computed tomography scans of 86 shoulders free of arthritic or anatomic deformities were studied. Two surgeons independently digitized a series of points, including the intersection of the 3 bone branches of the scapular spine (Y), the center of the glenoid surface (G), the most medial point of the scapula (MS), the cortical convergence (CC) of the anterior and posterior margins of the glenoid, the base of the coracoid (BC), the anterior (HA) and posterior (HP) margins of the subchondral bone. Results: The mean mediolateral distances between G and Y, BC, CC were respectively − 19.6 mm, − 1.5 mm, and − 36.8 mm. The consistency of anatomic landmarks was greatest for Y (standard deviation (SD) =2.3 mm; interquartile range (IQR) =3 mm), compared to BC (SD = 4.6 mm; IQR = 7 mm), and CC (SD = 6.6 mm; IQR = 8 mm). The repeatability of anatomic landmarks was excellent for all measurements. The mean ratios (relative to humeral head size) of distances between G and Y, BC, CC were respectively − 0.45, − 0.04, and − 0.85. The consistency of ratios was greatest for Y (SD = 0.05; IQR = 0.06), compared to BC (SD = 0.11; IQR = 0.14), and CC (SD = 0.13; IQR = 0.17). The repeatability of ratios was excellent for Y and BC, while it was good for CC. Conclusions: The Y-plane is a reliable reference for glenoid component positioning in shoulder arthroplasty, with a consistent distance from the center of the glenoid surface, and could therefore be suitable for preoperative planning. Study design: Level III, comparative anatomic study. [ABSTRACT FROM AUTHOR]

Background: Patients with Parkinson's disease might develop treatment‐resistant axial dysfunction after bilateral subthalamic stimulation. Objectives: To study whether lateralized stimulation (unilateral 50% amplitude reduction) for ≥21 days results in ≥0.13 m/s faster gait velocity in the dopaminergic ON state in these patients, and its effects on motor and axial function, quantitative gait and speech measures, quality of life, and selected cognitive tasks. Methods: Randomized, double‐blinded, double‐crossover trial. Results: In 22 participants (51–79 years old, 15 women), there were no significant changes in gait velocity, quality of life, cognitive, and speech measures. Reducing left‐sided amplitude resulted in a 2.5‐point improvement in axial motor Movement Disorder Society Unified Parkinson's Disease Rating Scale (MDS‐UPDRS) (P = 0.005, uncorrected) and a 1.9‐point improvement in the Freezing of Gait Questionnaire (P = 0.024, uncorrected). Conclusions: Lateralized subthalamic stimulation does not result in meaningful improvement in gait velocity in patients with Parkinson's disease who develop treatment‐resistant axial dysfunction after bilateral subthalamic stimulation. Left subthalamic overstimulation may contribute to axial deterioration in these patients. © 2022 International Parkinson and Movement Disorder Society [ABSTRACT FROM AUTHOR]

Objective: This study was undertaken to identify shared functional network characteristics among focal epilepsies of different etiologies, to distinguish epilepsy patients from controls, and to lateralize seizure focus using functional connectivity (FC) measures derived from resting state functional magnetic resonance imaging (MRI). Methods: Data were taken from 103 adult and 65 pediatric focal epilepsy patients (with or without lesion on MRI) and 109 controls across four epilepsy centers. We used three whole‐brain FC measures: parcelwise connectivity matrix, mean FC, and degree of FC. We trained support vector machine models with fivefold cross‐validation (1) to distinguish patients from controls and (2) to lateralize the hemisphere of seizure onset in patients. We reported the regions and connections with the highest importance from each model as the common FC differences between the compared groups. Results: FC measures related to the default mode and limbic networks had higher importance relative to other networks for distinguishing epilepsy patients from controls. In lateralization models, regions related to somatosensory, visual, default mode, and basal ganglia showed higher importance. The epilepsy versus control classification model trained using a 400‐parcel connectivity matrix achieved a median testing accuracy of 75.6% (median area under the curve [AUC] =.83) in repeated independent testing. Lateralization accuracy using the 400‐parcel connectivity matrix reached a median accuracy of 64.0% (median AUC =.69). Significance: Machine learning models revealed common FC alterations in a heterogeneous group of patients with focal epilepsies. The distribution of the most altered regions supports the hypothesis that shared functional alteration exists beyond the seizure onset zone and its epileptic network. We showed that FC measures can distinguish patients from controls, and further lateralize focal epilepsies. Future studies are needed to confirm these findings by using larger numbers of epilepsy patients. [ABSTRACT FROM AUTHOR]

Gregarious behaviours are common in animals and provide various benefits such as food acquisition and protection against predators. Many gregarious tropical species are shifting poleward under current ocean warming, creating novel species and social interactions with local temperate taxa. However, how the dynamics of these novel shoals might be altered by future ocean warming and acidification remains untested. Here we evaluate how novel species interactions, ocean acidification and warming affect shoaling dynamics, motor lateralization and boldness of range‐extending tropical and co‐shoaling temperate fishes under controlled laboratory conditions. Fishes were exposed to 1 of 12 treatments (combinations of three temperature levels, two pCO2 levels and two shoal type levels: mixed species or temperate only) for 38 days. Lateralization (a measure of asymmetric expression of cognitive function in group coordination and predator escape) of tropical and temperate species was right‐side biased under present‐day conditions, but side bias significantly diminished in tropical and temperate fishes under ocean acidification. Ocean acidification also decreased shoal cohesion irrespective of shoaling type, with mixed‐species shoals showing significantly lower cohesion than temperate‐only shoals irrespective of climate stressors. Tropical fish became bolder under ocean acidification (after 4 weeks), and temperate fish became bolder with increasing temperature, while ocean acidification dampened temperate fish boldness. Our findings highlight the direct effect of climate stressors on fish behaviour and the interplay with the indirect effects of novel species interactions. Because strong shoal cohesion and lateralization are key determinants of species fitness, their degradation under ocean warming and acidification could adversely affect species performance in novel assemblages in a future ocean, and might slow down tropical species range extensions. [ABSTRACT FROM AUTHOR]

The neural representation of visual‐spatial functions has traditionally been ascribed to the right hemisphere, but little is known about these representations in children, including whether and how lateralization of function changes over the course of development. Some studies suggest bilateral activation early in life that develops toward right‐lateralization in adulthood, while others find evidence of right‐hemispheric dominance in both children and adults. We used a complex visual‐spatial construction task to examine the nature of lateralization and its developmental time course in children ages 5–11 years. Participants were shown two puzzle pieces and were asked whether the pieces could fit together to make a square; responses required either mental translation of the pieces (Translation condition) or both mental translation and rotation of the pieces (Rotation condition). Both conditions were compared to a matched Luminance control condition that was similar in terms of visual content and difficulty but required no spatial analysis. Group and single‐subject analyses revealed that the Rotation and Translation conditions elicited strongly bilateral activation in the same parietal and occipital locations as have been previously found for adults. These findings show that visual‐spatial construction consistently elicits robust bilateral activation from age 5 through adulthood. This challenges the idea that spatial functions are all right‐lateralized, either during early development or in adulthood. More generally, these findings provide insights into the developmental course of lateralization across different spatial skills and how this may be influenced by the computational requirements of the particular functions involved. [ABSTRACT FROM AUTHOR]

Many vertebrate animals approximate, to various degrees, the "split‐brain" condition that results from surgery done in humans to treat severe epilepsy, with very limited connection between the left and right sides of the upper parts of the brain. The split‐brain condition has been the topic of extensive philosophical discussion, because it appears, in some circumstances, to give rise to two minds within one body. Is the same true of these animals? This article attempts to make progress on two difficult topics—animal experience, and the consequences of the human split‐brain condition—by considering both at once. [ABSTRACT FROM AUTHOR]

Forty‐eight newborn infants were tested in one of three multimodal stimulus conditions, in which auditory quantities were presented alongside visual object arrays in two test trials. These tests varied with respect to which side (either left or right) numerically matched the auditory number. The infants looked longer to the test trials in which the left side of the visual display exhibited a quantity that matched the presented auditory quantity. This study provides the first evidence for an untrained, innate bias for humans to preferentially process quantity information presented in the left field of vision. [ABSTRACT FROM AUTHOR]

Different species show an intriguing similarity in representing numerosity in space, starting from left to right. This bias has been attributed to a right hemisphere dominance in processing spatial information. Here, to disentangle the role of each hemisphere in dealing with spatial versus ordinal–numerical information, we tested domestic chicks during monocular versus binocular vision. In the avian brain, the contralateral hemisphere mainly processes the visual input from each eye. Four‐day‐old chicks learned to peck at the fourth element in a sagittal series of 10 identical elements. At testing, chicks faced a left‐to‐right–oriented series where the interelement distance was manipulated so that the third element was where the fourth had been at training; this compelled chicks to use either spatial or ordinal cues. Chicks tested binocularly selected both the fourth left and (to a lesser extent) right elements. Chicks tested monocularly chose the third and fourth elements on the seeing side equally. Interhemispheric cooperation resulted in the use of ordinal–numerical information, while each single hemisphere could rely on spatial or ordinal–numerical cue. Both hemispheres can process spatial and ordinal–numerical information, but their interaction results in the supremacy of processing the ordinal–numerical cue. [ABSTRACT FROM AUTHOR]

Left–right differences in the structural and functional organization of the brain are widespread in the animal kingdom and develop in close gene–environment interactions. The visual system of birds like chicks and pigeons exemplifies how sensory experience shapes lateralized visual processing. Owing to an asymmetrical posture of the embryo in the egg, the right eye/ left brain side is more strongly light‐stimulated what triggers asymmetrical differentiation processes leading to a left‐hemispheric dominance for visuomotor control. In pigeons (Columba livia), a critical neuroanatomical element is the asymmetrically organized tectofugal pathway. Here, more fibres cross from the right tectum to the left rotundus than vice versa. In the current study, we tested whether the emergence of this projection asymmetry depends on embryonic light stimulation by tracing tectorotundal neurons in pigeons with and without lateralized embryonic light experience. The quantitative tracing pattern confirmed higher bilateral innervation of the left rotundus in light‐exposed and thus, asymmetrically light‐stimulated pigeons. This was the same in light‐deprived pigeons. Here, however, also the right rotundus received an equally strong bilateral input. This suggests that embryonic light stimulation does not increase bilateral tectal innervation of the stronger stimulated left but rather decreases such an input pattern to the right brain side. Combined with a morphometric analysis, our data indicate that embryonic photic stimulation specifically affects differentiation of the contralateral cell population. Differential modification of ipsi‐ and contralateral tectorotundal connections could have important impact on the regulation of intra‐ and interhemispheric information transfer and ultimately on hemispheric dominance pattern during visual processing. [ABSTRACT FROM AUTHOR]

Background and Purpose: In 30% of the patients with focal epilepsy, an epileptogenic lesion cannot be visually detected with structural MRI. Ultra-high field MRI may be able to identify subtle pathology related to the epileptic focus. We set out to assess 7T MRI-derived volumetric and functional activity lateralization of the hippocampus, hippocampal subfields, temporal and frontal lobe in healthy subjects and MRI-negative patients with focal epilepsy.Methods: Twenty controls and 10 patients with MRI-negative temporal or frontal lobe epilepsy (TLE and FLE, respectively) underwent a 7T MRI exam. T1 -weigthed imaging and resting-state fMRI was performed. T1 -weighted images were segmented to yield volumes, while from fMRI data, the fractional amplitude of low frequency fluctuations was calculated. Subsequently, volumetric and functional lateralization was calculated from left-right asymmetry.Results: In controls, volumetric lateralization was symmetric, with a slight asymmetry of the hippocampus and subiculum, while functional lateralization consistently showed symmetry. Contrarily, in epilepsy patients, regions were less symmetric. In TLE patients with known focus, volumetric lateralization in the hippocampus and hippocampal subfields was indicative of smaller ipsilateral volumes. These patients also showed clear functional lateralization, though not consistently ipsilateral or contralateral to the epileptic focus. TLE patients with unknown focus showed an obvious volumetric lateralization, facilitating the localization of the epileptic focus. Lateralization results in the FLE patients were less consistent with the epileptic focus.Conclusion: MRI-derived volume and fluctuation amplitude are highly symmetric in controls, whereas in TLE, volumetric and functional lateralization effects were observed. This highlights the potential of the technique. [ABSTRACT FROM AUTHOR]

Forecasts from climate models and oceanographic observations indicate increasing deoxygenation in the global oceans and an elevated frequency and intensity of hypoxic events in the coastal zone, which have the potential to affect marine biodiversity and fisheries. Exposure to low dissolved oxygen (DO) conditions may have deleterious effects on early life stages in fishes. This study aims to identify thresholds to hypoxia while testing behavioral and physiological responses of two congeneric species of kelp forest fish to four DO levels, ranging from normoxic to hypoxic (8.7, 6.0, 4.1, and 2.2 mg O2/L). Behavioral tests identified changes in exploratory behavior and turning bias (lateralization), whereas physiological tests focused on determining changes in hypoxia tolerance (pCrit), ventilation rates, and metabolic rates, with impacts on the resulting capacity for aerobic activity. Our findings indicated that copper rockfish (Sebastes caurinus) and blue rockfish (Sebastes mystinus) express sensitivity to hypoxia; however, the strength of the response differed between species. Copper rockfish exhibited reduced absolute lateralization and increased escape time at the lowest DO levels, whereas behavioral metrics for blue rockfish did not vary with oxygen level. Both species exhibited decreases in aerobic scope (as a function of reduced maximum metabolic rate) and increases in ventilation rates to compensate for decreasing oxygen levels. Blue rockfish had a lower pCrit and stronger acclimation response compared to copper rockfish. The differences expressed by each species suggest that acclimatization to changing ocean conditions may vary, even among related species that recruit to the same kelp forest habitat, leading to winners and losers under future ocean conditions. Exposure to hypoxia can decrease individual physiological fitness through metabolic and aerobic depression and changes to anti‐predator behavior, with implications for the outcome of ecological interactions and the management of fish stocks in the face of climate change. [ABSTRACT FROM AUTHOR]

Extensive work implicates abnormal amygdala response during threatening stimuli in youth with antisocial behaviour. However, no research has examined whether youth identified in Primary and Secondary psychopathy subtypes would show differences in amygdala activity in response to threat acquisition and extinction. Latent profile analysis (LPA) was used to identify distinct antisocial groups based on participants' scores on callous–unemotional (CU) traits, anxiety, and familial abuse in a sample of 136 high‐risk adolescents (mean age = 17.7, SD = 1.6; 86% male). Functional MRI was then used to assess amygdala activation patterns during a classical differential delay threat‐conditioning task. In addition to the Primary and Secondary subtypes, we identified groups mainly high on anxiety and others who were mainly high on abuse. Participants in the Primary group showed lower right amygdala activity in response to neutral male faces compared to the low, Anxious, and Secondary groups, whereas participants in the group with history of abuse exhibited higher right amygdala activity during threat acquisition compared to the rest of the groups. During threat extinction, the Primary group showed lower right amygdala activity compared to the Secondary and abuse groups. This is the first study to reveal amygdala activation in identified psychopathy‐related variants during threat conditioning. We found that stratifying the sample based on the identified variants revealed amygdala functioning patterns that furthered our understanding of emotion‐based deficits among high‐risk adolescents. [ABSTRACT FROM AUTHOR]

Music processing and right hemispheric language lateralization share a common network in the right auditory cortex and its frontal connections. Given that the development of hemispheric language dominance takes place over several years, this study tested whether musicianship could increase the probability of observing right language dominance in left‐handers. Using a classic fMRI language paradigm, results showed that atypical lateralization was more predominant in musicians (40%) than in nonmusicians (5%). Comparison of left‐handers with typical left and atypical right lateralization revealed that: (a) atypical cases presented a thicker right pars triangularis and more gyrified left Heschl's gyrus; and (b) the right pars triangularis of atypical cases showed a stronger intra‐hemispheric functional connectivity with the right angular gyrus, but a weaker interhemispheric functional connectivity with part of the left Broca's area. Thus, musicianship is the first known factor related to a higher prevalence of atypical language dominance in healthy left‐handed individuals. We suggest that differences in the frontal and temporal cortex might act as shared predisposing factors to both musicianship and atypical language lateralization. [ABSTRACT FROM AUTHOR]

The purpose of this study was to describe the distinct regional distribution patterns of expression of the α7 and α4 subunits of nicotinic acetylcholine receptors (nAChRs) and their left‐right lateralisation in the rat hippocampus during the first 2 weeks of postnatal (P) development. Eighteen male pups were randomly divided into three groups: P0, P7, and P14. After removing the newborn brains, real‐time polymerase chain reaction, western blot, and immunohistochemistry techniques were used to evaluate expression of the receptors. Results indicated that the expression profile of these receptors were time‐ and spatially dependent. A significant increase was observed in the distribution of α7 and α4 nAChR subunits in the developing rat hippocampus from P0 to P7 (p <.001); however, there was a significant decrease from P7 to P14 (p <.05). As a spatial effect, the highest optical density (OD) was observed in the CA3 and CA2 regions of the hippocampus, while the lowest OD was in the dentate gyrus. Moreover, the distribution of α7 and α4 nAChR subunits in the left hippocampus was significantly higher than their counterparts in the right (p <.05). From these data, the expression patterns of α7 and α4 nAChR subunits exhibited left‐right asymmetry in the developing rat hippocampus. [ABSTRACT FROM AUTHOR]

Background: The auditory and prefrontal cortex supports auditory working memory processing. Many neuroimaging studies have shown hemispheric lateralization of auditory working memory brain regions in the presence of background noise, but few studies have focused on the lateralization of these regions during stochastic resonance.Purpose: To investigate the effects of stochastic resonance on lateralization of auditory working memory regions, and also to examine the brain-behavior relationship during stochastic resonance.Study Type: Cross-sectional.Population/subjects: Forty healthy young adults (18-24 years old).Field Strength/sequence: 3.0T, T1 , and T2 *-weighted imaging.Assessment: The auditory working memory performance was assessed using a backward recall task. Functional magnetic resonance imaging (fMRI) was used to measure brain activity during task performance. Functional MRI data were analyzed using SPM12 and WFU PickAtlas.Statistical Tests: One-way independent analyses of variance (ANOVA) were conducted on the behavioral and functional data to examine the main effect of noise level on performance (P < 0.01) and brain activity (P < 0.0042). Hemispheric lateralization was determined by calculating the laterality index. A paired samples t-test was performed to compare brain activity between hemispheres (P < 0.05). Pearson's correlation analysis and simple linear regression (P < 0.0042) were used to examine the relationship between brain activity and behavioral performance.Results: Performance was significantly enhanced during the 50 and 55 dB sound pressure level (SPL) conditions via the stochastic resonance mechanism [F(1,195) = 49.17, P < 0.001]. Activity of the right superior frontal gyrus in the 55 dB SPL condition was significantly positively correlated with performance (R2 = 0.681, P < 0.001).Data Conclusion: Our findings demonstrate changes in the lateralization of auditory working memory regions during stochastic resonance and suggest that the right superior frontal gyrus may be a strategic structure involved in the enhancement of auditory working memory performance.Level Of Evidence: 2 Technical Efficacy: Stage 4 J. Magn. Reson. Imaging 2020;51:1821-1828. [ABSTRACT FROM AUTHOR]

Functional outcomes of subscapularis (SSc) repair following reverse shoulder arthroplasty (RSA) remains controversial. SSc repair in combination with glenosphere lateralization was reported to yield worse clinical outcomes compared with the non‐lateralized glenosphere. The aim of this biomechanical study was to investigate how glenosphere lateralization and different re‐insertion sites can affect the biomechanics of the SSc after RSA. Nine patient‐specific RSA shoulder models were created from patients' computed tomography scans. Moment arms and SSc length were calculated for abduction, forward flexion, and internal rotation in 20° and 90° abduction for three configurations of glenosphere lateralization (standard/+0, +5, and +10 mm) and three SSc repair sites (native, superior, and inferior) and compared with the native shoulder. When compared with the native shoulder, RSA resulted in large adducting SSc moment arms that were antagonistic to the deltoid. Glenosphere lateralization had no effect on SSc moment arms in any motion. However, lateralization increased SSc tension beyond its anatomic length for +5 and +10 mm of lateralization when attached to its native insertion. A superior SSc repair site created the least adductive moment arm as well as the least amount of SSc lengthening. Increased glenosphere lateralization showed a significant increase in the SSc length, which in combination with its adductive moment arm can be antagonistic to deltoid function. However, a superior SSc repair site may help reduce the adductive SSc moment arm and allow for reduced tension on the repair as its length in that location is less than that of the native SSc. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:888‐894, 2020 [ABSTRACT FROM AUTHOR]

The left and right rodent hippocampi exhibit striking lateralization in some of the very neural substrates considered to be critical for hippocampal cognitive function. Despite this, there is an overwhelming lack of consideration for hemispheric differences in studies of the rodent hippocampus. Asymmetries identified so far suggest that a bilateral model of the hippocampus will be essential for an understanding of this brain region, and perhaps of the brain more widely. Although hypotheses have been proposed to explain how the left and right hippocampi contribute to behavior and cognition, these hypotheses have either been refuted by more recent studies or have been limited in the scope of data they explain. Here, I will first review data on human and rodent hippocampal lateralization. The implications of these data suggest that considering the hippocampus as a bilateral structure with functional lateralization will be critical moving forward in understanding the function and mechanisms of this brain region. In exploring these implications, I will then propose a hypothesis of the hippocampus as a bilateral structure. This discrete‐continuous hypothesis proposes that the left and right hippocampi contribute to spatial memory and navigation in a complementary manner. Specifically, the left hemisphere stores spatial information as discrete, salient locations, and the right hemisphere represents space continuously, contributing to route computation and flexible spatial navigation. Consideration of hippocampal lateralization in designing future studies may provide insight into the function of the hippocampus and resolve debates concerning its function. [ABSTRACT FROM AUTHOR]

Background: It is well known that a deficit in inhibitory control is a hallmark of Parkinson's disease (PD). However, inhibition is not a unitary construct, and it is unclear whether patients in the early stage of the disease (Hoehn and Yahr stage 1) exhibit a deficit in outright stopping (reactive inhibition), a deficit in the ability to shape their response strategies according to the context (proactive inhibition), or both.Objective: We assessed whether PD patients at Hoehn and Yahr stage 1 show a global or selective impairment in inhibitory control. As it has been suggested that inhibition relies upon a right-lateralized pathway, we tested whether left-dominant PD patients suffered from a more severe deficit in this executive function than right-dominant PD patients.Methods: Via a reaching stop-signal task, we assessed both proactive and reactive inhibition in 17 left-dominant PD and 17 right-dominant PD patients and in 24 age-matched participants.Results: We found that reactive inhibition was more impaired in PD patients than in healthy participants. However, proactive inhibition was not affected. Furthermore, we found no differences between left-dominant PD and right-dominant PD patients.Conclusions: For the first time, we found evidence for a deficit of reactive inhibition in the early-stage PD patients in the absence of evidence for deficits in proactive inhibition. These findings have clinical relevance as they provide critical insights on the time course of the disease. In addition, we confirmed, on a population of PD patients at Hoehn and Yahr stage 1, previous results showing that the onset of the disease does not affect inhibition. © 2019 International Parkinson and Movement Disorder Society. [ABSTRACT FROM AUTHOR]

Modulating the temporoparietal junction (TPJ), especially the right counterpart, shows promises in enhancing social cognitive ability. However, it is ambiguous whether the functional lateralization of TPJ determines people's responsiveness to brain stimulation. Here, this issue is investigated with an individual difference approach. Forty‐five participants attended three sessions of transcranial direct current stimulation (tDCS) experiments and one neuroimaging session. The results support the symmetric mechanism of left and right TPJ stimulation. First, the left and right TPJ stimulation effect are comparable in the group‐level analysis. Second, the individual‐level analysis reveals that a less right‐lateralized TPJ is associated with a higher level of responsiveness. Participants could be classified into positive responders showing cognitive enhancement and negative responders showing cognitive impairment due to stimulation. The positive responders show weaker connectivity between bilateral TPJ and the medial prefrontal cortex, which mediates the prediction of offline responsiveness by the lateralization and the social‐related trait. These findings call for a better characterization and predictive models for whom tDCS should be used for, and highlight the necessity and feasibility of prestimulation screening. [ABSTRACT FROM AUTHOR]

The dopaminergic system has a unique gating function in the initiation and execution of movements. When the interhemispheric imbalance of dopamine inherent to the healthy brain is disrupted, as in Parkinson's disease (PD), compensatory mechanisms act to stave off behavioral changes. It has been proposed that two such compensatory mechanisms may be (a) a decrease in motor lateralization, observed in drug‐naïve PD patients and (b) reduced inhibition ‐ increased facilitation. Seeking to investigate the differential effect of dopamine depletion and subsequent substitution on compensatory mechanisms in non‐drug‐naïve PD, we studied 10 PD patients and 16 healthy controls, with patients undergoing two test sessions — "ON" and "OFF" medication. Using a simple visually‐cued motor response task and fMRI, we investigated cortical motor activation — in terms of laterality, contra‐ and ipsilateral percent BOLD signal change and effective connectivity in the parametric empirical Bayes framework. We found that decreased motor lateralization persists in non‐drug‐naïve PD and is concurrent with decreased contralateral activation in the cortical motor network. Normal lateralization is not reinstated by dopamine substitution. In terms of effective connectivity, disease‐related changes primarily affect ipsilaterally‐lateralized homotopic cortical motor connections, while medication‐related changes affect contralaterally‐lateralized homotopic connections. Our findings suggest that, in non‐drug‐naïve PD, decreased lateralization is no longer an adaptive cortical mechanism, but rather the result of maladaptive changes, related to disease progression and long‐term dopamine replacement. These findings highlight the need for the development of noninvasive therapies, which would promote the adaptive mechanisms of the PD brain. [ABSTRACT FROM AUTHOR]

• GABA Aα1 and GABA B1 receptor subunits have already been expressed at birth and progressively increase up to the end of the second postnatal week. • There are not any lateral differences in GABA Aα1 between right and left hippocampus. • The optical density of GABA B1 is higher in the right CA2 at P14, and also right dentate gyrus at P7 than the left side. • The GABA B1 expression is higher than the GABA Aα1 in the hippocampi during the first two postnatal weeks. GABA is the chief inhibitory neurotransmitter in the adult brain. However, in the developing brain it acts as an excitatory transmitter causing depolarization. Thereby, activates calcium-dependent processes that are crucial for brain development. Accordingly, GABA receptors have the great role in the brain development, especially in the area with persisting neurogenesis such as hippocampus. The present study investigated the development and lateralization of two important subunits of GABA receptors, GABA Aα1 and GABA B1 , in the developing rat hippocampus during the neurogenesis-active period, at the first two postnatal weeks. Real-time PCR, western blot and immunohistochemistry were used. We found that the mRNA and protein of these GABA receptor subunits have already been expressed at birth and significantly increased at postnatal day (P) 7, and also at P14. Also, regarding the optical densities of GABA Aα1 and GABA B1 expressing hippocampal cells, we found a significant increase in the distribution pattern of these subunits in the all hippocampal subregions on day 14 after birth. The highest optical density of GABA Aα1 was observed in the CA3, and GABA B1 in the CA2. Nevertheless, our results did not show a significant laterality differences in the expression of these subunits. Regarding the crucial role of GABA receptors in the hippocampus development; they probably have the same effects on development of the rat hippocampus on both sides. [ABSTRACT FROM AUTHOR]

The rapid automatic specialized processing of printed words is signalled by the left-lateralization of the N1 component in the visual event-related potential (ERP). In the present study, we have investigated whether differences in N1 lateralization can be observed between Dutch children with and without (a familial risk of) dyslexia around the age of 12 years using a linguistic judgement task. Forty-five participants were included in the ERP analysis, 18 in the low familial risk group without dyslexia, 15 in the high familial risk group without dyslexia, and 12 in the high familial risk group with dyslexia. The results showed that although the N1 peaked slightly earlier in the left hemisphere, the N1 amplitude was right-lateralized in all groups. Moreover, there were no group differences in N1 amplitude or latency, and there was no relationship between reading (related) test scores and N1 characteristics. The results of the present study and our previous findings in adults suggest that print-tuning lateralization is a process that is still developing in adolescence. Because other studies did find N1 lateralization in younger readers with a print versus nonprint contrast, the current results seem to indicate that differences in N1 lateralization also depend on the experimental paradigm. [ABSTRACT FROM AUTHOR]

To assess the within‐subject intra‐scan session repeatability of language functional MRI (fMRI) activation maps in patients with brain tumors who were undergoing presurgical fMRI as part of their preoperative clinical workup. Sentence completion (SC) and silent word generation (SWG) tasks were used for language localization and hemispheric lateralization for identifying the primary language cortex. Within‐subject repeatability for each of these paradigms was assessed in right‐handed patients—37 for SC and 78 for SWG. Repeatability of activation maps between consecutive runs of the same task within the same scan session was evaluated by comparing lateralization indexes in holohemispheric and regional language areas. Displacement of center of activation between consecutive runs was also used to assess the repeatability of activation maps. Holohemispheric and regional language lateralization results demonstrated high intra‐subject intra‐scan repeatability when lateralization indices were calculated using threshold‐dependent and threshold‐independent approaches. The high repeatability is demonstrated both when centers of mass of activation are considered within key eloquent regions of the brain, such as Broca's area and Wernicke's area, as well as in larger more inclusive expressive and receptive language regions. We examined two well‐known and widely accepted language tasks that are known to activate eloquent language cortex. We have demonstrated very high degree of repeatability at a single‐subject level within single scan sessions of language mapping in a large cohort of brain tumor patients undergoing presurgical fMRI across several years at our institution. [ABSTRACT FROM AUTHOR]

Abstract: Assessing infant handedness has been controversial. Different assessment techniques and theoretical approaches produce different results. Evidence from a dynamic systems perspective showed that the development of postural control during infancy affects the expression of an infant's handedness. However, others found that developmental changes in postural control influenced the amount of symmetrical (bimanual) reaching during infancy, but not hand preference. Since most studies of infant handedness use age to assess development, perhaps measures of an infant's developing neuromotor control, irrespective of age, would better predict changes in an infant's hand preference. To assess neuromotor development, items from [Touwen's (1976) Neurological development in infancy. Lavenham, Suffolk: The Lavenham Press, LTD]. “Group III” indices were used. These items assess developmental changes in neuromotor abilities throughout the 6–14‐month age period. Hand preference for acquiring objects was measured during these same months. Group Based Trajectory Models (GBTM) of 380 infants identified four different groups of infants according to the trajectory of the development of their hand preferences (32% Early Right, 12% Early Left, 25% Late Right, 30% No Preference). A multilevel model was used to compare these four developmental trajectories according to age and neuromotor development. Age, not neuromotor development, is a better predictor of differences in developmental trajectories of the four hand preference groups. However, Late Right infants are significantly less developed at 6 months than No Preference, Early Right and Left infants and both Early Right and Left infants are most advanced at 6 months. All groups exhibit similar rates of neuromotor development indicating no “catch‐up” by the Late Right infants. Thus, any assessment of infant handedness will incorporate necessarily four groups of infants with differently developing hand preferences and neuromotor abilities. [ABSTRACT FROM AUTHOR]

The dichotic‐listening paradigm with verbal stimuli is a widely employed behavioral task for the assessment of hemispheric asymmetry for speech and language processing. Participants with assumed left‐hemispheric dominance report the right‐ear stimulus with higher probability than the left‐ear stimulus. However, there is substantial between‐subject and trial‐to‐trial variability observed in the paradigm, motivating scrutiny of the task set‐up and theoretical models. Here, we give an in‐depth discussion of specific features of stimulus material and experimental parameters, as well as the conditions of stimulus/response selection, which explain a significant proportion of intra‐ and inter‐individual variability. Carefully considering these factors should be at the heart of any experimental planning when using the dichotic‐listening paradigm to achieve an optimal testing situation for measuring laterality and avoid confounds in between‐subject and between‐group comparisons. [ABSTRACT FROM AUTHOR]

While neurotypical individuals over‐attend to the left‐side of centrally‐presented visual stimuli, this bias is reduced in individuals with autism/high levels of autistic traits. Because this difference is hypothesized to reflect relative reductions in right‐hemisphere activation, it follows that increasing right‐hemisphere activation should increase leftward bias. We administered transcranial direct current stimulation (tDCS) over the right posterior parietal cortex to individuals with low levels (n = 19) and high levels (n = 19) of autistic traits whilst they completed a greyscales task. Anodal tDCS increased leftward bias for high‐trait, but not low‐trait, individuals, while cathodal tDCS had no effect. This outcome suggests that typical attentional patterns driven by hemispheric lateralization could potentially be restored following right‐hemisphere stimulation in high‐trait individuals. Autism Res2018, 11: 385–390. © 2017 International Society for Autism Research, Wiley Periodicals, Inc. Lay Summary: Attentional differences between individuals with and without autism may reflect differences in underlying activation of the left and right hemispheres. In this study, we combine an attentional task that reflects relative hemispheric activation with non‐invasive cortical stimulation, and show that attentional differences between healthy individuals with low and high levels of autistic‐like traits can be reduced. This outcome is encouraging, and suggests that other aspects of attention in autism (e.g., face processing) may stand to benefit from similar stimulation techniques. [ABSTRACT FROM AUTHOR]

Altered striatocortical functional connectivity has been suggested to be a trait marker of schizophrenia spectrum disorders, including schizotypal personality. In the present study, we examined the association between schizotypal personality traits and striatocortical functional connectivity in a sample of healthy adults. The German version of the Schizotypal Personality Questionnaire was obtained from N = 111 participants recruited from the general public. Resting-state functional magnetic resonance imaging scans were acquired at 3T. Six striatal seed regions in each hemisphere were defined and striatocortical resting-state functional connectivity (rsFC) as well as its lateralization indices was calculated. Regression analysis showed that schizotypy scores, especially from the positive dimension, were positively correlated with rsFC between ventral striatum and frontal cortex and negatively associated with rsFC between dorsal striatum and posterior cingulate. No significant associations were found between negative dimension schizotypy and striatocortical rsFC. We also found positive correlations between schizotypy total scores and lateralization index of right dorsal caudate and right rostral putamen. In conclusion, the present study extends previous evidence of altered striatocortical rsFC in the schizophrenia spectrum. The observed associations resemble in part the alterations observed in psychotic patients and their relatives, providing support for dimensionality from schizotypal personality to the clinical disorder. Hum Brain Mapp 39:288-299, 2018. © 2017 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Objectives The question of whether there is a continuum or a dichotomy among patients with schizophrenia ( SZ) and bipolar disorders ( BD) has not been clearly resolved and remains a challenge. Thus, the identification of specific biomarkers of these disorders might be helpful. The present study investigated the volume of the corpus callosum ( CC) and functional lateralization for language as potential biomarkers and their relationships in SZ and BD. Methods The study included 20 patients with SZ, 20 patients with BD and 40 healthy controls ( HC). A functional lateralization index ( FLI) was computed for each participant within the language comprehension network. For each participant, the volume of the total CC and those of three subregions were extracted. These variables and their anatomo-functional relationships were investigated. Results In comparison to HC, SZ patients presented a decreased leftward lateralization for language, whereas this was not found in BD patients. However, as compared to SZ patients and HC, BD patients showed a reduction in CC volume associated with a lower leftward lateralization for language. Conclusions Our study revealed that SZ patients displayed a reduction of the leftward functional lateralization for language; however, no reduction of CC volume was observed, whereas BD patients presented a decreased volume of the CC associated with a lower leftward asymmetry for language. The results of our study detected distinct anomalies in both SZ and BD that may be considered as specific biomarkers of these disorders related to neurodevelopmental models. [ABSTRACT FROM AUTHOR]

Regulation of the formation and rewiring of neural circuits by neuropeptides may require coordinated production of these signaling molecules and their receptors that may be established at the transcriptional level. Here, we address this hypothesis by comparing absolute expression levels of opioid peptides with their receptors, the largest neuropeptide family, and by characterizing coexpression (transcriptionally coordinated) patterns of these genes. We demonstrated that expression patterns of opioid genes highly correlate within and across functionally and anatomically different areas. Opioid peptide genes, compared with their receptor genes, are transcribed at much greater absolute levels, which suggests formation of a neuropeptide cloud that covers the receptor-expressed circuits. Surprisingly, we found that both expression levels and the proportion of opioid receptors are strongly lateralized in the spinal cord, interregional coexpression patterns are side specific, and intraregional coexpression profiles are affected differently by left- and right-side unilateral body injury. We propose that opioid genes are regulated as interconnected components of the same molecular system distributed between distinct anatomic regions. The striking feature of this system is its asymmetric coexpression patterns, which suggest side-specific regulation of selective neural circuits by opioid neurohormones.--Kononenko, O., Galatenko, V., Andersson, M., Bazov, I., Watanabe, H., Zhou, X. W., Iatsyshyna, A., Mityakina, I., Yakovleva, T., Sarkisyan, D., Ponomarev, I., Krishtal, O., Marklund, N., Tonevitsky, A., Adkins, D. L., Bakalkin, G. Intra- and interregional coregulation of opioid genes: broken symmetry in spinal circuits. [ABSTRACT FROM AUTHOR]

Introduction The present study explored the role of resting state and personality component ( BIS/ BAS measure) on prefrontal cortical responsiveness to emotional cues. Indeed, we supposed that lateralized resting activity (right vs. left) and approach ( BAS) versus avoidance ( BIS) attitude may explain the successive emotional processing within the prefrontal cortex ( PFC) based on the stimulus valence (positive and negative emotional cues). Methods Hemodynamic (functional near-infrared spectroscopy, fNIRS) and electroencephalographic ( EEG) measures were considered. The resting and experimental brain activity were registered when subjects ( N = 21) viewed emotional positive versus negative stimuli (International Affective Picture System, IAPS). LIReeg and LIRnirs (lateralized Index Response) during resting state, and LIeeg and LInirs during emotional processing were acquired. Results A set of regression analyses was applied to the multiple measures. The predictive effect of resting activity and approach/avoidance dichotomy were elucidated. Indeed, more left/right resting activity (for both LIReeg and LIRnirs) predicted the successive more brain left/right response ( LIeeg and LInirs) to emotional cues. Second, significant effects were revealed as a function of valence (increased right response to negative stimuli; increased left response to positive stimuli) during emotion processing. Third, higher BAS values explained an increased left cortical activity in resting state and in experimental condition for positive cues. In contrast, higher BIS values marked an increased right activity in resting state and in experimental condition in response to negative cues. Conclusion The significance of trait component for both resting and emotional cue processing was discussed at light of the present results. [ABSTRACT FROM AUTHOR]

Categories can affect our perception of the world, rendering between-category differences more salient than within-category ones. Across many studies, such categorical perception ( CP) has been observed for the basic-level categories of one's native language. Other research points to categorical distinctions beyond the basic level, but it does not demonstrate CP for such distinctions. Here we provide such a demonstration. Specifically, we show CP in English speakers for the non-basic distinction between 'warm' and 'cool' colors, claimed to represent the earliest stage of color lexicon evolution. Notably, the advantage for discriminating colors that straddle the warm-cool boundary was restricted to the right visual field-the same behavioral signature previously observed for basic-level categories. This pattern held in a replication experiment with increased power. Our findings show that categorical distinctions beyond the basic-level repertoire of one's native language are psychologically salient and may be spontaneously accessed during normal perceptual processing. [ABSTRACT FROM AUTHOR]

The current study investigated the behavioural response of Lepomis macrochirus following exposures to elevated carbon dioxide ( CO2). For this, L. macrochirus were held at ambient p CO2 (160 μatm p CO2) for 7 days, then exposed to elevated p CO2 (8300 μatm p CO2) for 5 days, and then returned to ambient conditions for a further 5 days to recover. At the end of each exposure period, several behavioural metrics were quantified (boldness, lateralization and activity). Data showed no change in lateralization and most metrics associated with performance and boldness. During the boldness test, however, average velocity, velocity in the thigmotaxis (outer) zone and proportion of activity in the thigmotaxis zone increased with p CO2 exposure. During post-exposure, average velocity of L. macrochirus decreased. In addition, individual rank was repeatable during the pre-exposure and post-exposure period in three of the 17 metrics investigated (average velocity in the middle zone, average velocity near object and total shuttles to the object zone), but not during the CO2 exposure period, suggesting that elevated p CO2 disrupted some behavioural performances. Overall, this study found elevated p CO2 caused disruption to behaviours of freshwater fishes such as L. macrochirus and effects do not appear to be as serious as has been shown for marine fishes. [ABSTRACT FROM AUTHOR]

Objectives Handedness is an important marker for lateralization of humans in the modern and fossil record. For the most part, Neandertals and their ancestors are strongly right-handed. We describe a single tooth from a Neandertal level at Vergisson 4 (Vg 4-83). This left upper central incisor shows all the features typical of Neandertal incisors. It also exhibits a predominance of left-handed striations. Methods Striations on the incisor's labial surface were mapped at 20x magnification using Photoshop. Angulations of the striations were determined from their deviation from the maximum mesio-distal line and were analyzed using NIH's freeware, Image J. Results Of the 60 labial surface striations, Vg 4-83 shows a strong predominance of left-handed striations (46; 76.7%), which are statistically significantly different ( p < .001 with a two-tailed chi2 test) from the small number (3) of right-handed striations. Discussion The identification of another left-handed Neandertal adds to our understanding about handedness variation in this fossil hominin. Given the high frequency of right-handed Neandertals, the 90: 10 modern ratio is still preserved in this group. [ABSTRACT FROM AUTHOR]