Decoding neural signals for the control of movement

by Sara Solla (Northwestern University, USA)

Monday 20 Apr 2009, 15:00 → 16:00 Europe/Stockholm

RB35

Neurons in primary motor cortex provide the signals that control the execution of movements. In order to investigate the code used by this neural ensemble, we analyze data obtained for an awake behaving monkey through an implanted multielectrode array that records the activity of about one hundred neurons during the execution of a sequence of reaches to nearby targets. Ensemble activity is represented in a high-dimensional space in which each axis represents the activity of a single neuron, but the observed correlations among neurons whose activity is detectably modulated by the task suggest that the population activity defines a low-dimensional space within the high-dimensional space of independent firing activities. We have used linear and nonlinear methods for dimensionality reduction to find the low-dimensional structure that captures the data. The use of multidimensional scaling in conjunction with an empirical measure of geodesic distances yields a low-dimensional manifold whose intrinsic coordinates capture the geometry of the task in the external physical space while reflecting the functional conectivity of the ensemble.