Komal K. Kukkar

Symmetrical resistance training induces corticospinal and cortical network plasticity; however, the neural consequences of asymmetrical resistance training (offset loading or OL) remain unclear. In this preliminary study, fourteen healthy adults completed eighteen supervised upper-extremity training sessions over a 6-week intervention period. Participants were allocated to either an offset loading (OL) intervention group (n = 8) or a conventional symmetrical resistance training active control group (AC; n = 6). Electroencephalography (EEG) recordings were acquired during motor task performance at baseline, 3 weeks, and 6 weeks. Directed functional connectivity among predefined cortical regions was quantified, and longitudinal changes were assessed using Friedman tests with false-discovery-rate correction for multiple comparisons. Significant changes in the OL group were observed involving two cortical pathways after correction for multiple testing. Connectivity from the right parietal cortex to the right sensorimotor cortex increased over time (Friedman χ² = 8.00, q = 0.037), with post hoc analyses showing a significant increase between the midpoint and post-training assessments (q = 0.047; effect size r = 0.894). No significant longitudinal changes in cortical connectivity were identified in the AC group. Six weeks of OL training was associated with selective strengthening of directed connectivity within prefrontal-to-sensorimotor and parietal-to-sensorimotor cortical pathways. In contrast, conventional symmetrical resistance training was not associated with detectable changes in connectivity. These findings suggest that asymmetrical loading may induce task-specific reorganization of cortical networks involved in sensorimotor processing and motor control.

In this study, we subject the conventional physiological interpretation of independent component analysis (ICA) applied to EEG, the small-patch model, to systematic falsification, and propose an alternative large-patch model. The small-patch model assumes that ICs correspond to localized cortical patches with < 1 cm2. However, this assumption has remained unvalidated. The small-patch model predicts that approximately 70% of sources are localized within sulci up to 15 mm deep, with rapidly changing dipole orientations across the cortex. In contrast, the large-patch model (>6-10 26 cm2) predicts relatively stable radial orientations accompanied by physiologically implausible source depths due to depth bias. First, we conducted a stimulation study using a forward-inverse modeling framework with a four-layer head conductor model. We confirmed that depth bias emerges when a single equivalent dipole is fitted to a potential field generated by a broad array of parallel dipoles. This observation led to the key hypothesis that the presence of depth bias in empirical data would favor the large-patch model. Second, we analyzed resting-state EEG from two European open datasets comprising 820 recordings (62-64 channels), yielding dipole depth and orientation distributions for nearly 15,000 qualified brain ICs. Results showed that more than 80% of ICs were localized at physiologically implausible depths (19-26 mm), favoring the large patch model. A novel dipole-orientation analysis revealed broad, low-spatial-frequency structure in dipole orientations, further supporting the large-patch model. We conclude that the revised physiological interpretation of ICA aligns with electrophysiological literature and computational insights into EEG-specific spatial scaling laws.

Comprehending how forces are applied to an object during manipulation can help provide important insights into the quality of behavior in daily tasks. We have developed the Bead Maze Hand Function test to objectively measure the quality of hand function in children. This test aims to measure how well an individual performs the activity by integrating measures of time and force control. The main objective of this study was to examine associations between a common clinical measure, the Box and Block Score (BBS), and variables on the Bead Maze Hand Function test that were either time-based or force-based. The sample was composed of neurotypical developing adolescent participants (N=23). We found that the time (duration) on the double curve wire (most complex) was the best predictor of BBT. Furthermore, we found that force-based variables were weak predictors of the clinical, time-based BBS. These findings support the integration of time and force-based metrics to holistically quantify the quality of motor behavior. Linking these metrics into a unified score may serve as a better way to analyze adolescent motor behavior and predict future motor or neurodegenerative conditions.

Understanding the forces imparted onto an object during manipulation can shed light on the quality of daily manual behaviors. We have developed an objective measure of the quality of hand function in children, the Bead Maze Hand Function Test, which quantifies how well the individual performs the activity by integrating measures of time and force control. Our main objectives were to examine associations between performance (total force output) on the Bead Maze Hand Function Test (BMHFT) and (1) performance on a sensitive measure of force scaling obtained on a laboratory-based dexterous manipulation task, and (2) general sensory and motor parameters important for fine motor skills. A total of 39 typically developing participants ranging in age from 5 to 10 years old (n = 28) and 15 to 17 years (n = 11). We found that the anticipatory coordination of digit forces was the best predictor of performance on the Bead Maze Hand Function test. We also found that factors such as age, gender, and pinch strength were associated with the BMHFT performance. These findings support the integration of more sensitive sensorimotor metrics, such as the total applied force, into clinical assessments. Linking the development of sensorimotor capabilities to functional task performance may facilitate more targeted and effective intervention strategies, ultimately improving a child’s participation in daily activities.

Clinical tests such as the Berg Balance Scale (BBS) and Timed Up and Go (TUG) are used to assess balance and functional mobility following stroke. These tests are subjective due to dependence on the assessor’s judgment and the patient’s effort, potentially affecting their sensitivity to early or subtle balance recovery. This study aimed to identify objective markers of BBS and TUG among corticomuscular coherence (CMC) and force platform center of pressure (COP) measures using machine learning in 18 chronic stroke patients and 15 age-matched healthy adults. Participants performed a continuous balance task on a sway-referenced force platform with simultaneous recording of EEG, EMG, and COP data. We used a two-stage machine learning approach: first, a binary classifier, such as XGBoost and Elastic Net models, reduced dimensionality while preserving interpretability, and selected features that differentiated between stroke and healthy controls; second, regression models used selected features to identify predictors of BBS and TUG. Tibialis anterior delta-band CMC and medio-lateral root mean square COP predicted BBS and TUG. These features capture the dynamic stability mechanisms shared across the two clinical tests of balance and functional mobility. Soleus theta-band CMC asymmetry index predicted BBS, whereas TUG was predicted by biceps femoris beta-band CMC asymmetry index and rectus femoris beta-band CMC. These muscle-specific measures highlighted the use of ankle and hip strategies for the control of balance during BBS and TUG tests, respectively. Our study provides objective neurophysiological and biomechanical markers that may be sensitive to subtle changes in balance following stroke.

In this study, we investigated the changes in functional connectivity between cortical regions for balance control during a challenging balance task with advancing age. Fourteen young and fourteen late middle-to-older adults performed a challenging balance task that manipulated somatosensory information while their brain activity was recorded using electroencephalography. Both groups showed common activation regions within the posterior cingulate cortex (PCC) and premotor cortex (PMC) during the balance task. The late middle-to-older group showed significantly weaker PCC to PMC functional connectivity than the young group. This finding indicated poor sensorimotor processes during altered reliance on somatosensory inputs for balance maintenance. The regularity of foot center of pressure fluctuations measured using sample entropy was greater in the late middle-to-older group than the young group, suggesting a shift from automatic control to cognitive control of balance. Weaker PCC to PMC connectivity in late middle-to-older adults was associated with greater regularity of foot center of pressure fluctuations. In late middle-to-older adults, an additional cortical region was activated, the prefrontal cortex, during the balance task. Our findings suggest a shift from the parietal-to-frontal sensorimotor network to the prefrontal network for dynamic control of balance with advancing age.

This report contains a description of physiological and motion data, recorded simultaneously and in synchrony using the hyperscanning method from two professional dancers using wireless mobile brain-body imaging (MoBI) technology during rehearsals and public performances of “LiveWire” - a new composition comprised of five choreographed music and dance sections inspired by neuroscience principles. Brain and ocular activity were measured using 28-channel scalp electroencephalography (EEG), and 4-channel electrooculography (EOG), respectively; and head motion was recorded using an inertial measurement unit (IMU) placed on the forehead of each dancer. Video recordings were obtained for each session to allow for tagging of physiological and motion signals and for behavioral analysis. Data recordings were collected from 10 sessions over a 4-month period, in which the dancers rehearsed or performed (in front of an audience) choreographed expressive movements. A detailed explanation of the experimental set-up, the steps carried out for data collection, and an explanation on the usage are provided in this report.

Although significant progress has been made in understanding the cortical correlates underlying balance control, these studies focused on a single task, limiting the ability to generalize the findings. Different balance tasks may elicit cortical activations in the same regions but show different levels of activation because of distinct underlying mechanisms. In this study, twenty young, neurotypical adults were instructed to maintain standing balance while the standing support surface was either translated or rotated. The differences in cortical activations in the frontocentral region between these two widely used tasks were examined using electroencephalography (EEG). Additionally, the study investigated whether transcranial magnetic stimulation could modulate these cortical activations during the platform translation task. Higher delta and lower alpha relative power were found over the frontocentral region during the platform translation task when compared to the platform rotation task, suggesting greater engagement of attentional and sensory integration resources for the former. Continuous theta burst stimulation over the supplementary motor area significantly reduced delta activity in the frontocentral region but did not alter alpha activity during the platform translation task. The results provide a direct comparison of neural activations between two commonly used balance tasks and are expected to lay a strong foundation for designing neurointerventions for balance improvements with effects generalizable across multiple balance scenarios.

Although significant progress has been made in understanding the cortical correlates underlying balance control, these studies focused on a single task limiting the ability to generalize the find-ings. Different balance tasks may elicit cortical activations in the same regions but show different levels of activation because of distinct underlying mechanisms. In this study, we instructed twenty young, neurotypical adults to maintain standing balance while the standing support surface was either translated or rotated and investigated the differences in cortical activations between these two widely used tasks using whole head electroencephalography (EEG). Addi-tionally, we investigated whether transcranial magnetic stimulation could modulate these cortical activations. We found higher delta and lower alpha relative power over the fronto-central region during the platform translation task when compared to the platform rotation task suggesting greater engagement of attentional and sensory integration resources for the former. Continuous theta burst stimulation (cTBS) over the supplementary motor area (SMA) significantly reduced delta activity in the fronto-central region but did not alter alpha activity during the platform translation task. Our results provide a direct comparison of neural activations between two commonly used balance tasks and are expected to lay a strong foundation for designing neuro-interventions for balance improvements with effects generalizable across multiple balance scenarios.

BACKGROUND Autistic Spectrum Disorder (ASD) presents with a multitude of problems such as physical, social, emotional, psychological, etc. Most common physical problems are impairments in standing balance and posture. It is unknown whether these impairments have any association between tactile sensation or are purely due to deficits in sensory processing and integration. We hypothesized that foot tactile sensation in ASD is positively correlated to performance in standing balance as measured by Pediatric Balance scale. METHODS The data collected at Heartshare Human Services of New York was used for secondary analysis. It consisted of 12 participants and included: 1. Muscle and joint ROM testing to rule out any muscle involvement in balance problems. 2. Tactile sensation testing at four sites on sole of foot bilaterally using Semmes Weinstein monofilament. 3. Pediatric Balance Scale (PBS) for balance testing. RESULTS We found significant positive correlation between cutaneous tactile sensation (SWF) and Pediatric Balance scale (PBS) measures in our participants i.e., reduced tactile sensation was moderately associated with impaired balance score. CONCLUSIONS We propose that during conventional clinical assessment for individuals with ASD, foot tactile sensation should not be overlooked, and included as a part of somato-sensory assessment. In addition, enhancing foot tactile sensation could also be used for targeted interventions to improve balance in children with ASD.