Laminar analysis of motion information processing in macaque V5.

Although it has been repeatedly shown that properties of striate cells depend on laminar position, no information is available about the vertical organization of primate extrastriate cortex. Laminar analysis in the part of macaque V5 (the middle temporal visual area) devoted to the central 10 degrees in the visual field, reveals that interaction between a moving bar and a moving texture differs systematically between layers. We found that cells for which the direction selectivity does not depend on texture motion occur mainly in layer 4 and in the infragranular layers. Cells with only pseudomodulation of direction selectivity were found throughout the cortical depth. Cells for which direction selectivity was abolished when both patterns moved inphase occur outside layer 4 and therefore represent a higher processing stage. These 3 types differ not only in laminar position but also in velocity selectivity and in strength of texture response. These findings suggest that the 3 classes represent distinct physiological types of neurons dedicated to different stages of motion processing which takes place in V5, and suggest that these cells may play different roles in the guidance of eye movements.