Biology subjects

Hawe, R. L.

Publications and source records attributed to Hawe, R. L..

3 recordsLinked to original sources

bioRxiv2025

Characterizing Complex Upper Limb Movements with and without Visual Feedback in Typically Developing Children

The development of upper limb movements has been primarily described through reaching movements, which may not have the complex motor planning and execution demands of many daily tasks. In this study, we introduced a complex task in which individuals had to navigate their hand from a start target through two openings in a simple maze to reach an end target. In half the trials, participants received visual feedback of their hand position, and in half of the trials they did not. Thirty-one participants ages 8 to 17 years completed the study. We found that with visual feedback, reaction time, number of speed peaks, movement time, and hand path length all decreased with age. Number of speed peaks, movement time, and hand path length were all increased without visual feedback, however, the impact of removing visual feedback was greatest on the younger children and decreased with age. Our results demonstrate that complex upper limb movements are refined across childhood and adolescence, with a decreasing reliance on visual feedback likely due to increasing feedforward control and improved ability to use proprioceptive feedback. This task can be applied to clinical populations such as cerebral palsy to assess impairments in motor planning and execution as well as determine how proprioceptive impairments contribute to complex movements. NEW AND NOTEWORTHYThis study used a novel paradigm to examine how children plan and execute complex upper limb movements, both when they have visual feedback of hand position available and when they do not. We show that with age, performance with visual feedback improves reflecting advancing motor planning and execution abilities. Older children were less impacted by removing visual feedback than younger children, likely due to improved feedforward control and use of proprioceptive feedback.

neuroscience↗

bioRxiv2024

Abnormal mu rhythm state-related cortical and corticospinal responses in chronic stroke

The motor cortexs activity is state-dependent. Specifically, the sensorimotor mu rhythm phase relates to fluctuating levels of primary motor cortex (M1) excitability, previously demonstrated in young and healthy volunteers. However, it is unknown whether this observation is generalizable to individuals with brain lesions after a stroke. We investigated the phase relationship between the mu rhythm and cortical excitability by combining real-time processing of electroencephalography (EEG) signals and transcranial magnetic stimulation (TMS) of M1. In 11 chronic subcortical stroke survivors and 12 similar-aged healthy volunteers, we applied TMS to M1 at the peak, falling, trough, and rising phase of the sensorimotor mu oscillation. As outcome measures, we investigated the M1-to-muscle excitability by measuring motor-evoked potentials (MEPs) and local cortical activation by measuring TMS-evoked potentials (TEPs). We found that M1-to-muscle excitability in stroke survivors and older volunteers shows a phase-dependency similar to that in young healthy adults. That is, MEPs were increased and decreased at the trough and peak of the mu rhythm, respectively. However, individuals with stronger stroke-related motor symptoms showed a decreased phase preference. Further, phase-dependency was abolished in the local cortical activity, as measured with EEG, in the stroke-affected hemisphere, in contrast to the non-affected hemisphere as well as either hemisphere in healthy volunteers. Altogether, these results shed light on the state-dependency of motor cortex excitability after stroke. Our results indicate that the strength of phase preference of TMS motor responses could indicate the severity of motor impairment. These results could enable the development of improved TMS paradigms for recovery of motor impairment after stroke.

neuroscience↗

bioRxiv2024

Characterization of Bilateral Reaching Development Using Augmented Reality Games

HighlightsO_LIWe developed augmented reality games to examine bilateral reaching in 133 children C_LIO_LISymmetric and asymmetric reaching developed in parallel C_LIO_LISynchrony in hands reaching targets improved with age C_LIO_LIChildren continued to improve through age 17, though slower rate after 12 years C_LIO_LIFemales demonstrated better reaching performance than males C_LI Bilateral coordination is commonly impaired in neurodevelopmental conditions including cerebral palsy, developmental coordination disorder, and autism spectrum disorder. However, we lack objective clinical assessments that can quantify bilateral coordination in a clinically feasible manner and determine age-based norms to identify impairments. The objective of this study was to use augmented reality and computer vision to characterize bilateral reaching abilities in typically developing children. Typically developing children (n=133) ages 6-17 years completed symmetric and asymmetric bilateral reaching tasks in an augmented reality game environment. We analyzed the number of target pairs they could reach in 50 seconds as well as the time lag between their hands reaching the targets. We found that performance on both tasks developed in parallel, with development slowing but not plateauing after age 12. Children performed better on the symmetric task than asymmetric, both in targets reached and with shorter hand lags. Variability between children in hand lag decreased with age. We also found gender differences with females outperforming males, which were most pronounced in the 10-11 year olds. Overall, this study demonstrates parallel development through childhood and adolescence of symmetric and asymmetric reaching abilities. Furthermore, it demonstrates the ability to quantify bilateral coordination using computer vision and augmented reality, which can be applied to assess clinical populations.

neuroscience↗