[Organization of neurons in the cat Clare-Bishop area which react to photic stimulation].

Organization of neurons in Clare-Bishop associative cortex was investigated by means of microelectrode vertical penetrations and recording of the neuronal responses to visual stimulation. Of 463 electrode penetrations 255 showed responses to visual stimulation. In 131 penetrations only 1 or 2 visually driven neurons were noted, in 55 cases more than 3 neurons were registered. Of 55 investigated penetrations 8 showed distinct columnar organization, i.e. all neurons in each column had similar characteristics. In 24 penetrations neurons were organized in groups of 2 or 3 similar neurons intermingled with neurons of other types. In 18 penetrations a great degree of overlapping of the receptive fields of neurons in a single column was observed. In 5 penetrations a chaotic organization of different neurons was found. A conclusion is made that the columnar organization of visually driven neurons as a functional cortical unit can not be regarded as a prominent feature in Clare-Bishop area.