Principalis, oralis and interpolaris responses to whisker movements provoked by air jets in rats.

The present study was designed to compare the electrophysiological characteristics of the principalis, oralis and interpolaris nuclei of the trigeminal sensory complex under stimulation of the vibrissae by air puffs. This stimulus generates deflection profiles resembling those induced by contact with real objects in natural conditions. Three populations of neurons were identified in each nucleus according to their mean spiking frequency at rest. The three nuclei differed in terms of their mean spiking frequencies, the response latencies of their neurons and the proportions of each neuron population observed in single and multi-unit recordings. Findings suggest different information processing tasks for each nucleus.