''Irregular'' visual receptive fields of neurons of the cat lateral geniculate body

Using point-to-point testing, the spatial organization of receptive fields (RF) of the neurons of the lateral geniculate body (LGB) was studied in cats with pretrigeminally transected brainstem (without general anesthesia). In 60% of studied neurons (96 units of 160 examined), configuration of their RF considerably differed from round or ellipsoid. The shape of such RF was frequently rather complex, and they were qualified as irregular receptive fields (IRF). Presentation of the stable flickering spot throughout the entire surface of 60 IRF (63%) evoked qualitatively similar responses of a neuron, i.e., these IRF were homogeneous. In 29 cells the responses were of the on-off type, 22 neurons generated off responses, and on responses were observed in 9 cells. In the rest of the IRF (37%), it was possible to differentiate the subfields, whose stimulation evoked generation of different types of responses, i.e., there IRF were heterogeneous. In the case of moving stimuli, the neurons with homogeneous IRF showed no directional selectivity, while such selectivity was observed in most units with heterogeneous IRF.