High gain transmission of single impulses through dorsal column nuclei of the cat.

Paired recordings were made in the cat from neurones of dorsal column nuclei and from intact pacinian sensory fibres of the hindlimb interosseous nerve. Direct evidence is presented for central neurones being driven by single impulses arriving over just one sensory nerve fibre. Transmission through this sensory relay appears to be optimized for the detection of minimal sensory inputs. Two mechanisms operate for the amplification of such inputs. First, individual sensory fibres can exert divergent, suprathreshold actions on multiple target neurones, and second, a single impulse coming over one input fibre can induce pairs or bursts of output spikes from its target neurones.