Task-dependent selectivity of movement-related neuronal activity in the primate prefrontal cortex

We studied movement-related neuronal activity in the dorsolateral prefrontal cortex from the perspective of a general role for the prefrontal cortex in controlling motor behavior to achieve a specific goal according to the requirements of a given task. Monkeys were trained to perform two delayed motor tasks. The first task involved reaching for a target that matched the shape of a cue. The second task involved reaching for a target that matched the location of the cue. A majority (54%) of 175 movement-related prefrontal neurons exhibited preference for either the target shape or the type of task requirements. Sixty-four neurons (34%) were selectively active while reaching for a circle or a triangle. On the other hand, the activity of 59 neurons (34%) depended on whether the task required matching the shape or the location. These properties, characterizing the movement-related neuronal activity in the prefrontal cortex, rarely were found in the arm area of the primary motor cortex. Only 1 of 130 movement-related neurons (0.8%) showed task selectivity, and none showed target-shape selectivity.