Regional Distribution of Functions in Area 7

Abstract

Many of the results referred to above suggest that within area 7 there are functionally different regions. Electric stimulation studies indicated a difference between areas 7a and 7b; the Vogts (1919) showed that stimulation of area 7a produced eye movements whereas stimulation of area 7b produced hand movements (Fig. 38). The microelectrode recording studies of Leinonen et al. in my laboratory (Leinonen et al. 1979, Leinonen and Nyman 1979, Leinonen 1980). showed that the lateral part of afea 7 (7b) contains more sornatic mechanisms than the studies of Mountcastle et al. (Mountcastle et al. 1975, Lynch et al. 1977, Motter and Mountcastle 1981) which were performed mainly in area 7a and were dominated by visual and oculomotor mechanisms. In a preliminary mapping study we showed that visual-oculomotor mechanisms were concentrated in the medial part of area 7, whereas somatic mechanisms were more common laterally and posteriorly (Hyvärinen and Shelepin 1979). Furthermore, most laterally in area 7b in the parietal operculum and in the upper lip of the Sylvian fissure Robinson and Burton (1980b,c) described purely somaesthetic responses.