Functional organization of neurons in cat striate cortex: variations in ocular dominance and receptive-field type with cortical laminae and location in visual field

Abstract

1. Binocularity and receptive-field type of cortical neurons were assessed relative to the cortical layer in which the neurons were recorded and to receptive-field position in the visual field. 2. Receptive fields were observed up to 2 degrees into the ipsilateral half of the visual field. In the region up to 2 degrees on either side of the vertical meridian, the relative contribution of the ipsilateral eye was reduced. This progression in ocular dominance from ipsilateral to contralateral visual field agrees well with the distribution of X-cells about the nasotemporal division. 3. The region of maximum binocularity in each hemifield was found to be a 12 degree wide vertical strip extending from the vertical meridian to 12 degrees contralateral. In the representation of the central 12 degree strip, most units in all cortical layers were binocular. 4. Low levels of binocularity were observed at a considerable distance before the monocular portion of the visual field was reached. 5. The decrease in binocularity for simple cells occurred closer to the vertical meridian than for complex cells. 6. The proportions of cells classified as simple or complex did not change with position in the visual field. 7. At all locations in the visual field, complex cells showed a higher percentage of binocularity than simple cells. 8. The proportions of two types of simple cells, I and II, and complex cells were variable between cortical layers. Layer IV contained predominantly simple II cells, whereas layer V contained predominantly complex cells. 9. The results are discussed in terms of visual perception and the dynamic pattern of visual stimulation around a moving animal, the optic flow field.