PRIOR INFORMATION PRESHAPES THE POPULATION REPRESENTATION OF MOVEMENTDIRECTION IN MOTOR CORTEX

SINGLE neuron activity was recorded in monkey motor cortex during the execution of pointing movements in six directions. The amount of prior information was manipulated by varying the range of precued direction s. A distribution of neural population activation was constructed in t he space of movement directions. This population representation of mov ement direction was preshaped by the precue. Peak location and width r eflected the precued range of movement directions. From this preshaped form, the population representation evolved continuously in time and gradually in parameter space toward a more sharply peaked distribution centered on the parameter value specified by the response signal. A t heoretical model of motor programming generated a similar temporal evo lution of an activation field representing movement direction.