Abstract
Raphe magnus cells that are inhibited by skin pinching fire spontaneously with strongly preferred interspike intervals (mean cycle 85 ms,
n=33). In pentobarbital-anesthetized rats, mid-cycle cathodal activation (0.3 ms) or end-cycle anodal block (30–60 ms) at ≈1 Hz through the extracellular recording microelectrode delayed expected spikes; respective post-stimulus latencies peaked on avarage at 1.17 (
n=14) and 0.40 (
n=6) cycles. Feedback inhibition following random excitation, but not free-running intrinsic or afferent oscillations, may therefore cause the rhythm.
