Maps of complex motion selectivity in the superior temporal cortex of the alert macaque monkey: a double-label 2-deoxyglucose study

The superior temporal sulcus (STS) of the macaque monkey contains multiplevisual areas. Many neurons within these regions respond selectively tomotion direction and to more complex motion patterns, such as expansion,contraction and rotation. Single-unit recording and optical recordingstudies in MT/MST suggest that cells with similar tuning properties areclustered into columns extending through multiple cortical layers. In thisstudy, we used a double-label 2-deoxyglucose technique in awake, behavingmacaque monkeys to clarify this functional organization. This techniqueallowed us to label, in a single animal, two populations of neuronsresponding to two different visual stimuli. In one monkey we comparedexpansion with contraction; in a second monkey we compared expansion withclockwise rotation. Within the STS we found a patchy arrangement ofcortical columns with alternating stimulus selectivity: columns of neuronspreferring expansion versus contraction were more widely separated thanthose selective for expansion versus rotation. This mosaic ofinterdigitating columns on the floor and posterior bank of the STS includedarea MT and some neighboring regions of cortex, perhaps including area MST.