Visuomotor Areas of the Frontal Lobe JEFFREY

That frontal cortex is involved in visually guided behavior has been known for over a century. Since the pioneering work of Ferrier, several areas in frontal cortex have been identified as having visual responses and playing some role in producing movements of the eyes, head, and limbs. Comprehensive reviews of frontal lobe organization and function have appeared (Fuster, 1989; GoldmanRakic, 1987, 1988; Passingham, 1993; Levin et ai., 1991; Perecman, 1987; Stuss and Benson, 1986; Petrides and Pandya, 1994). This chapter will survey recent findings regarding the possible roles of the different areas of frontal cortex in the production of visually guided movements. Areas of disagreement in the literature will be examined. Although some neurons in primary motor cortex are visually responsive (e.g., Kwan et al., 1985), such signals seem to be fairly nonspecific activations. Most emphasis will be on eye movements and the function of the frontal and supplementary eye fields. Recent experiments will also be reviewed that examine the function of the agranular cortex and the granular dorsolateral and ventrolateral prefrontal cortex. The state of knowledge and the author's competence wane toward the rostral pole. Nevertheless, the orbitofrontal and cingulate cortex are integral if poorly understood parts of frontal cortex that relate to affect and personality. As reviewed in this volume, the visual system in primates seems to be orga-