An image of the pattern of neuronal excitation produced in a model of primary visual cortex when a point of light passes across the field of view. The image shows the pattern of cortical excitation produced by three points moving in parallel paths with 3 different speeds. The presence, direction and speed of the motion can be characterized by the resultant pattern of activity in the excitable membrane. Visual cortex is modeled here as a 2-dimensional excitable membrane of neurons connected mainly with nearby neighbors and the observed patterns are analogous to bow waves generated by a boat traveling faster than the speed of free water waves.

Experiments to detect these wave patterns using f M R I and tetrode electrophysiological methods are under way at a laboratory in Europe that is collaborating with the laboratory of Don Glaser in the Department of Molecular and Cell Biology. The Glaser Lab is engaged in ongoing efforts to detect and characterize the psychophysical implications of these activity patterns.