MASS-ACTION VIEW OF SINGLE-CELL RESPONSES TO STIMULATION OF THE RECEPTIVE-FIELD AND OR BEYOND - EXEMPLIFICATION WITH DATA FROM THE RABBIT PRIMARY VISUAL-CORTEX/

Whereas single cells in the visual cortex prefer moving light bars, ma ss-action responses are evoked better by diffuse luminance changes. Th is discrepancy was investigated by quantitatively comparing the respon se properties of individual cells with those of a representative group of cells. The latter responses were derived from the single-cell resp onses, which were obtained from recording in the rabbit. These quantit ative estimates of mean responses resolve the discrepancy between the single-cell domain and the mass-action domain: from the single-cell po int of view: a properly oriented moving-bar stimulus is much more effe ctive than a diffuse-light stimulus. The corresponding mass-action res ponse to one common moving-bar stimulus, however, is as small as the m ean response to a diffuse-light stimulus (which may even be presented at retinotopically non-corresponding sites). The peak intensities of t hese mass responses are even much stronger with the diffuse-light stim uli. The same conclusions are valid for the cat, as could be verified from published data. The restrictions of the local receptive field con cept that may be implied by the mass-action view of cortical activity and the potential functional relevance of mass activities are discusse d.