How the Barrel Cortex Became a Working Model for Developmental Plasticity: A Historical Perspective

Abstract

For half a century now, the barrel cortex of common laboratory rodents has been an exceptionally useful model for studying the formation of topographically organized maps, neural patterning, and plasticity, both in development and in maturity. We present a historical perspective on how barrels were discovered, and how thereafter, they became a workhorse for developmental neuroscientists and for studies on brain plasticity and activity-dependent modeling of brain circuits. What is particularly remarkable about this sensory system is a cellular patterning that is induced by signals derived from the sensory receptors surrounding the snout whiskers and transmitted centrally to the brainstem (barrelettes), the thalamus (barreloids), and the neocortex (barrels). Injury to the sensory receptors shortly after birth leads to predictable pattern alterations at all levels of the system. Mouse genetics have increased our understanding of how barrels are constructed and revealed the interplay of the molecular programs that direct axon growth and cell specification, with activity-dependent mechanisms. There is an ever-rising interest in this sensory system as a neurobiological model to study development of somatotopy, patterning, and plasticity at both the morphologic and physiological levels. This article is part of a group of articles commemorating the 50th anniversary of the Society for Neuroscience.

NMDA receptor–BK channel coupling regulates synaptic plasticity in the barrel cortex

“…The barrel field area in the primary somatosensory cortex, also known as the barrel cortex (BC), processes information from peripheral sensory receptors for onward transmission to cortical and subcortical brain regions ( 22 , 23 ). Sensory information is received in the BC from different nuclei of the thalamus.…”

Neurosensory development of the four brainstem-projecting sensory systems and their integration in the telencephalon

“…Rodents best describe the detailed terminals of trigeminal neurons (Erzurumlu and Gaspar, 2020). Central projection of these neurons depends on Hoxa2, Lmx1b, Epha4/7, Slit2, Robo1/2, Neuropilin1, and Sema3a to define the maxillary branch that innervates the unique whiskers for normal central innervation of r2 (mandibular) and r3 (maxillary).…”

Spatial organization and transitions of spontaneous neuronal activities in the developing sensory cortex

“…The barrel morphological features are formed essentially during the first postnatal week and depend on the thalamocortical activity (Goncalves et al., 2013; Narboux‐Neme et al., 2012). The rodent S1 is widely recognized as an ideal model to understand the mechanisms contributing to the formation and refinement of cortical neuronal circuits (Erzurumlu & Gaspar, 2020; Erzurumlu & Kind, 2001; Iwasato & Erzurumlu, 2018; Wu et al., 2011).…”