Speaker: John Krall
Research Advisor: Prof. Bolu Ajiboye
Title: Neural Population Dynamics of Simultaneous Finger Movements in Human Motor Cortex
Abstract: Brain Machine Interfaces (BMIs), combined with Functional Electrical Stimulation (FES) movement neuroprostheses, can be used to restore functional reach and grasp movements to those with tetraplegia. The ReHAB clinical trial aims to enhance the capability of BMI + FES neurotechnologies by restoring dexterous hand function. Current BMIs scale poorly to high degree-of-freedom (DoF) movements such as coordinated finger movements, due in part to our incomplete understanding of how the brain generates motor commands for several joints simultaneously. Previous studies have shown neural population activity in motor cortex during single joint movements is well modeled as a dynamical system that evolves in time following intrinsic dynamical rules. We studied the spatial and temporal modes of the neural dynamics during simultaneous finger movements and their relation to those observed during single finger movements. We found that the trajectories traced out in neural state-space during each movement condition were confined to separate low-dimensional manifolds; however, the dynamics within each manifold were consistent across the conditions. Additionally, we found that there is a linear relationship between the location and orientation of each multi-finger movement condition’s manifold and those of the single-finger conditions that compose it. These findings offer key insights into the underlying principles governing the activity of motor cortex during simultaneous finger movements, which may potentially be leveraged to enhance the capability of the ReHAB system and BMIs in general.