Organization of the Perioral Representation of the Primary Somatosensory Cortex in Prairie Voles (Microtus ochrogaster).

Introduction: 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.

Methods: In the current study, we used electrophysiological multiunit 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.

Results: 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 and that 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.

Conclusions: The relative magnification of the perioral representation in S1 reflects the importance of these regions for sensory-mediated behaviors such as tactile interactions in biparental care and social bonding. This highlights how environmental and behavioral factors shape S1 organization through brain-body synergy, suggesting that relatively small changes in experience can drive adaptive cortical plasticity that, over subsequent generations, drives the cortical phenotypic diversity across the rodent clade and mammals in general.