Parvalbumin‐containing neurons, perineuronal nets and experience‐dependent plasticity in murine barrel cortex

Abstract

The ability to undergo experience-dependent plasticity in the neocortex is often limited to early development, but also to particular cortical loci and specific experience. In layers II-IV of the barrel cortex, plasticity evoked by removing all but one vibrissae (univibrissa rearing) does not have a time limit except for layer IV barrels, where it can only be induced during the first postnatal week. In contrast, deprivation of every second vibrissa (chessboard deprivation) removes time limits for plasticity. The mechanism permitting plasticity in response to chessboard deprivation and halting it in reply to univibrissa rearing is unknown. Condensation of chondroitin sulfate proteoglycans into perineuronal nets and an increase in intracortical inhibition mediated by parvalbumin-containing interneurons are implicated in closing the critical period for ocular dominance plasticity. These factors could also be involved in setting up the critical period in barrels in a way that depends on a particular sensory experience. We therefore examined changes in density of parvalbumin-containing cells and perineuronal nets during development of mouse barrel cortex and after brief univibrissa and chessboard experience in adolescence. We observed a progressive increase in the density of the two markers across cortical layers between postnatal day 10 and 20, which was especially pronounced in the barrels. Univibrissa rearing, but not chessboard deprivation, increased the density of perineuronal nets and parvalbumin-containing cells in the deprived barrels, but only those that immediately neighbour the undeprived barrel. These data suggest the involvement of both tested factors in closing the critical period in barrels in an experience-dependent manner.

Reduced Labeling of Parvalbumin Neurons and Perineuronal Nets in the Dorsolateral Prefrontal Cortex of Subjects with Schizophrenia

“…A reduction in excitatory inputs could result in an activity-dependent downregulation of PV and PNN components in schizophrenia. Consistent with this interpretation, neuronal activity in sensory cortices during the closure of a critical period is associated with both the maturation of PV neurons and the appearance of PNNs (Nowicka et al, 2009;Ye and Miao, 2013).…”

MeCP2 regulates the timing of critical period plasticity that shapes functional connectivity in primary visual cortex

“…On the other hand, once initiated, critical period plasticity rises, peaks, and terminates with a rather fixed schedule (16), in part defined by several molecular markers including those that mark PNNs (29). Thus, our detection of much enhanced PNN at P15 and P30 further hints at an early closure of the critical period.…”

“…PNNs consist of specialized extracellular matrix proteins such as chondroitin sulfate proteoglycans and interdigitate with synaptic contacts (28). The developmental increase of PNNs is regulated by visual experience (29), and PNNs in mature V1 mainly surround the soma and proximal dendrites of PV interneurons (Fig. 3) (30).…”

Developmental Switch in Spike Timing-Dependent Plasticity at Layers 4–2/3 in the Rodent Barrel Cortex

“…In the barrel cortex, it is not well established whether GABAergic maturation is also required for plasticity to occur (but see Nowicka et al, 2009). However, the results of this study suggest that if the STDP rule switches at approximately P13-P15, spike sequence at L4 -L2/3 synapses suddenly become important after the transition.…”