Abstract
This study examined functional roles played by the dorsal premotor cortex (PMd) and the primary motor cortex (MI) in conditional visuomotor behavior, in which it is necessary to recognize a visual object initially and to choose a motor act associated with it subsequently. For the first time after these two processes, a subject can prepare and execute it. We recorded neuronal activity in the PMd and MI of two macaque monkeys (Macaca fuscata) while they were performing a version of a conditional visuomotor behavior. We found that a group of PMd neurons retrieved conceptual motor information (i.e., a relative position of a target) indicated by a visual object. We also found that an entire process in which the conceptual motor information was transformed into a physical movement was reflected in a population of neuronal activity in the PMd. By contrast, involvement of the MI in these processes was meager. Instead, a great majority of MI neurons was active while a reaching movement was being executed, and the activity mainly reflected the direction of the movement. These results suggest that the PMd is involved in core processes for establishing a physical movement based on information instructed by a visual object, while the MI is mainly involved in executing a planned movement. [J Physiol Sci. 2008;58 Suppl:S191]
