Visual topography of striate projection zone (MT) in posterior superior temporal sulcus of the macaque.

Abstract

SUMMARY AND CONCLUSIONS 1. The representation of the visual field in the striate projection zone in the posterior portion of the superior temporal sulcus of the macaque (MT) was mapped with multiunit electrodes. The animals were immobilized and anesthetized and in each animal 25-35 electrode penetrations were typically made over several recording sessions. 2. MT contains a representation of virtually the entire contralateral visual field. The representation of the vertical meridian forms its ventrolateral border and lies near the bottom of the lower bank of the superior temporal sulcus (STS). The representation of the horizontal meridian runs across the floor of STS. The upper field is located ventral and anterior and the lower field dorsal and posterior. The medial border lies at the junction of the floor of STS and its upper bank. 3. MT is similar to striate cortex in being a first-order transformation of the visual field. In both areas, receptive-field size and cortical magnification increase with eccentricity. MT is much smaller than striate cortex and has much larger receptive fields at a given eccentricity and a cruder topography. 4. The results further support the suggestion that MT in the macaque is homologous to visual area MT in New World primates.