Receptive field organization of disparity-sensitive cells in Macaque medial superior temporal cortex

Binocular disparities are crucial for building an accurate three-dimensiona l representation of the peripersonal environment in a viewer-centred frame of reference. Previous studies have shown that visual cells of the medial s uperior temporal cortex (MST) have large receptive fields and that they are sensitive to disparities present in large surfaces. By using a reverse cro ss-correlation technique in this study we tested 175 disparity-sensitive un its recorded from MST in the awake Macaca mulatta monkey to determine if th ese large receptive fields are homogeneous in terms of disparity sensitivit y. We found that the receptive fields of 50 cells (50 out of 175, 29%) show ed subregions with specific disparity sensitivity. These subregions present ed eccentricities from 0.8 to 22.3 degrees and their sizes varied from 1.6 to 15.3 degrees (2). This particular receptive field organization represent s a suitable mechanism for encoding the location of small objects within ou r peripersonal space.