Dorsal raphe neuronal responses to thalamic centralis lateralis and medial prefrontal cortex electrical stimulation.

The present study gives evidence for ascending pathways from the dorsal raphe nucleus (DR) to the centralis lateralis nucleus (CL) and to the medial prefrontal cortex (PFCx). Single-unit recordings were done at dorsal raphe level and electrical stimulation was applied at CL and PFCx regions causing antidromic and orthodromic activity in DR cells. The speed conduction difference of the antidromic DR responses to CL and PFCx stimulation was significantly different, but the latencies of the same responses showed no differences. Therefore, we conclude that the DR pathways to CL and to PFCx structures reach their target cells at similar times.