SECOND-ORDER VISUAL MECHANISMS: REVIEW OF RESEARCH

The review is devoted to the analysis of studies aimed at studying second-order visual filters as a mechanism for preattentive grouping of local visual information by striate neurons (first-order filters). The development of ideas about possible mechanisms for combining primary visual features is analyzed, with the emphasis on studies of the properties of second-order filters. The questions of spatial organization and principles of interaction of filters of the first and second orders are considered. The results indicating the multichannel nature of the pooling mechanism and possible relationship between the frequency and orientation settings of the filters of the first and second order are described. A model for organizing filters of the second order is presented, possible neurophysiological correlates of these mechanisms are analyzed, role of the second-order mechanisms in visual perception is considered.