Modality and Topographic Properties of Single Neurons of Cat’s Somatic Sensory Cortex1

THE PRESENT PAPER describes some observations upon the modality and topographical attributes of single neurons of the first somatic sensory area of the cat’s cerebral cortex, the analogue of the cortex of the postcentral gyrus in the primate brain. These data, together with others upon the response latencies of the cells of different layers of the cortex to peripheral stimuli, support an hypothesis of the functional organization of this cortical area. This is that the neurons which lie in narrow vertical columns, or cylinders, extending from layer II through layer VI make up an elementary unit of organization, for they are activated by stimulation of the same single class of peripheral receptors, from almost identical peripheral receptive fields, at latencies ers. It is early These which are not significantly different for the cells of the various layemphasized that this pattern of organization obtains only for the repetitiv neurons ‘e responses may be rela of ted cortical in quite neurons different to brief peripheral stimuli. organization patterns when analyzed in terms of later discharges. A report of these experiments was made to the American Physiological Society in September, 1955 (10, 17).