Motor cortical activity during sinusoidal tracing

It is shown that single-cell activity recorded from the proximal arm area of the motor cortex during the performance of arm reaching tasks can be related to the direction of movement. This was found for single straight movements made directly to a target and for movements in which direction changed continually. Responses from a population of 226 directionally sensitive cells were combined to form neural images of the trajectory. The construction of these images suggests that trajectory-related information in the motor cortex is generated incrementally throughout the task and is coded in an instantaneous coordinate system