Reactivation of Ocular Dominance Plasticity in the Adult Visual Cortex

TLDR

In young animals monocular deprivation induces an ocular dominance shift, but this shift is absent in adults, partly due to inhibitory chondroitin sulphate proteoglycans in the extracellular matrix. The study tested whether the maturation of the ECM inhibits experience‑dependent plasticity in adult visual cortex. The timing of CSPG perineuronal net formation aligns with the critical period’s closure and can be postponed by dark rearing. Degrading CSPGs with chondroitinase‑ABC in adult rats restored ocular dominance plasticity, causing a shift toward the nondeprived eye and showing that the mature ECM normally suppresses experience‑dependent plasticity.

Abstract

In young animals, monocular deprivation leads to an ocular dominance shift, whereas in adults after the critical period there is no such shift. Chondroitin sulphate proteoglycans (CSPGs) are components of the extracellular matrix (ECM) inhibitory for axonal sprouting. We tested whether the developmental maturation of the ECM is inhibitory for experience-dependent plasticity in the visual cortex. The organization of CSPGs into perineuronal nets coincided with the end of the critical period and was delayed by dark rearing. After CSPG degradation with chondroitinase-ABC in adult rats, monocular deprivation caused an ocular dominance shift toward the nondeprived eye. The mature ECM is thus inhibitory for experience-dependent plasticity, and degradation of CSPGs reactivates cortical plasticity.