Response properties of 180 pyramidal neurons (11 layer II, 66 layer III, 7 layer IV, 76 layer V and 20 layer VI neurons) in the cat parietal cortex (areas 5 and 7) were examined intracellularly with stimulations of the cerebellar nucleus (CN), the thalamic ventroanterior nucleus (VA) and the lateral posterior nucleus (LP) under pentobarbital anesthesia. Pyramidal neurons were identified morphologically or electrophysiologically with antidromic responses by pontine nuclei (PN) stimulation. CN and VA stimulations evoked EPSPs in layer II, III, V and VI pyramidal neurons, but scarcely induced EPSPs in layer IV pyramidal ones. The mean latencies of CN-EPSPs were nearly the same through layers II to V, giving values of around 4.5 ms, but that of layer VI pyramidal neurons was much longer (5.5 +/- 0.8 ms: mean +/- SD). Those of VA-EPSPs were also nearly the same through all layers (around 2.2-2.8 ms). In case of LP stimulation, EPSPs were scarcely recorded in layer II and IV pyramidal neurons. The mean latency of LP-EPSPs was much shorter in layer III (2.6 +/- 1.0 ms) than those in layers V and VI (3.8-3.9 ms). It was noted that pyramidal neurons in layers II and III responded more frequently to CN and VA stimulations than those in deeper layers, and that the amplitudes of CN- and VA-EPSPs were large and conspicuous in layer III. In layer V, a statistical difference in the latency distributions of CN-, VA-, and LP-EPSPs between fast- and slow-type pyramidal neurons was not detected. The present results suggest that there exist the different modes of thalamocortical (T-C) innervations in the cat parietal cortex; the superficial T-C innervation of CN-VA inputs and the deep T-C innervation of LP inputs.