Fig. 5.

Examples of unit responses elicited by electrical stimuli delivered in IL (A–C) or BS (D and E). A and B show data for 2 different BL neurons, D shows a Ce cell, and C and E show LA neurons. In a high proportion of BL neurons (but never in Ce cells), IL stimulation elicited antidromic response characterized by fixed latency (A, top) and collision with spontaneous action potentials (A, bottom). In a few BL cells, IL stimulation evoked orthodromic responses consisting of single spikes (B) or, very rarely, spike bursts (C). The latter response pattern was only seen in 3 LA cells (their position is marked by an arrow in Fig. 4A). In a high proportion of Ce neurons (but never in BL cells), BS stimuli elicited antidromic responses characterized by a fixed latency (D, top) and collision with spontaneous action potentials (D, bottom). BS stimuli elicited orthodromic responses in a few rare LA cells (E).