Organization of the perioral representation of the primary somatosensory cortex in prairie voles (Microtus ochrogaster).

Abstract

Prairie voles (Microtus ochrogaster) are one of the few mammalian species that are monogamous and engage in the biparental rearing of their offspring. Biparental care impacts the quantity and quality of care the offspring receives. The increased attention by the father may translate to heightened tactile contact the offspring receives through licking and grooming. In the current study, we used electrophysiological multiunit recording techniques to define the organization of the perioral representation in the primary somatosensory area (S1) of prairie voles. Functional representations were related to myeloarchitectonic boundaries. Our results show that most of S1 is occupied by the representation of the contralateral mystacial whiskers and the lower and upper lips. The mystacial vibrissae representation encompassed a large portion of the caudolateral S1, while the representation of the lower and upper lips occupied a large portion of the rostrolateral aspect of S1. We found that neuronal populations representing the perioral structures tended to have small receptive fields relative to other body part representations on the head. The representation of the mystacial whiskers and perioral structures was coextensive with cytoarchitectonically defined barrel fields that extend from the caudolateral to a rostrolateral aspect of S1. We discuss our findings in the context of the magnification of behaviorally relevant sensory surfaces in other rodents, the ubiquity of the barrel systems in rodents, and behaviors associated with specialized sensory surfaces.