The rodent barrel field cortex integrates somatosensory information from two separate
thalamic nuclei, the ventral posterior medial nucleus (VPM) and the rostral sector of the
posterior complex (POm). This paper compares the sensory responses of POm and VPM
cells in urethane‐anesthetized rats as a first step in determining how cortex integrates
multiple sensory pathways. A complete representation of the contralateral body surface was
identified in POm. Trigeminal receptive fields (RFs) of POm and VPM cells were mapped by …

The projection from the whiskers of the rat to the S‐I (barrel) cortex is segregated into two
separate pathways—a lemniscal pathway relayed by the ventral posterior medial nucleus
(VPM) to cortical barrels, and a paralemniscal pathway relayed by the rostral sector of the
posterior complex (POm) to the matrix between, above, and below barrels. Before
investigating how the barrel cortex integrates these sensory pathways, it is important to learn
more about the influence of the various inputs to the two thalamic nuclei. Based on the …