Coding of spatial co-ordinates on neurones of the feline visual association cortex.

The receptive field properties of 131 visual neurons lying along the anterior ectosylvian sulcus were studied with extracellular recordings in barbiturate-anaesthetized, immobilised, artificially ventilated cats. A stationary visual noise pattern was presented in an area of 24x32 degrees, in which an 8x8 degrees portion moved randomly at a speed of 10 deg/s. A definite best area characterized by maximal firing rate was found, from where the firing rate declined monotonously towards the periphery of the receptive field. The best area locations were distributed in a 40x40 degrees region around the area centralis. These results seem to verify a rather robust capacity in AEV neurones for stimulus localization, in spite of their immense receptive fields.