Humans and monkeys share a highly-developed capacity to guide accurate movements of the eye and arm toward objects in space, a capacity which is largely implemented in the cerebral cortex. Cortical control of eye and arm guidance have been studied through single-neuron electrophysiology in macaque monkeys and metabolic imaging (e.g. functional magnetic resonance imaging [fMRI] and PET) in humans. Until recently, data obtained from humans and monkeys could not be directly compared, since the correlation between neuronal and metabolic activity has yet to be firmly established. To address this issue, we propose to conduct parallel experiments in awake, behaving humans and monkeys. Humans and monkeys will perform eye and arm movement tasks in closely matched fMRI environments. The goals for the proposed experiments are twofold: (1) We will test specific hypotheses concerning the cerebral organization of eye and arm control in each species, with particular emphasis on localizing the neural substrates for eye-hand coordination. (2) We will investigate potential homologies between cortical organization in monkeys and humans by comparing data obtained from the two species under similar conditions. Our results are likely to enhance our understanding of higher brain function in both human and non-human primates, and will be of particular value in interpreting neuroimaging experiments conducted in humans. ? ?
