The whisker thalamus

Abstract

Sensory information from the whiskers ascends through the trigeminal nuclei in the brainstem to the midbrain and forebrain where it reaches primarily the superior colliculus, the pretectal nuclei, the zona incerta, and the thalamus. The whisker thalamus is at the center of this network because it regulates passage to the barrel cortex as dictated by behavioral state. From barrel cortex, descending activity is fed back to the thalamus and to the other nuclei that process ascending information. Thalamocortical cells in the whisker thalamus receive sensory, cortical, inhibitory, and modulatory afferents. The physiological properties of this network and the functions that emerge from its activity are described here.