Characteristics of simultaneously recorded thalamic and cortical neurons. Comparison of SIs between simultaneously recorded and shuffled neuron pairs, pre- and postadaptation, for cortical barrel (A), thalamus (B), and early thalamic (C) responses. In both preadaptation barrel pairs and early thalamic responses, the SIs of simultaneously recorded neurons were greater than those of shuffled pairs (P < 0.01). However, after adaptation, only the barrel pairs display greater than chance SI values postadaptation. In D, RC is plotted as a function of SI for unconnected thalamocortical pairs.