A physicalist approach to first-order analysis of optic flow fields in extrastriate cortical areas

A useful representation of visual motion information can be based on first-order elementary components of the optic flow. Medial superior temporal (MST) cells are probably better suited for the analysis of visual motion in terms of such elementary components. This paper discusses the processing stage in the visual pathway from middle temporal (MT) to MST cells. The processing of MST cells is formulated as a physicalist operation, exploiting a log-polar representation of stimulus velocity performed by MT cells. A wave-like spatiotemporal activation function is introduced to describe the global properties of optic flow at MT level. MST cells perform oriented filtering operations on this activation function by approximating a template matching between the optic flow stimulus and the cell preferences for gaze-centered elementary flow components