Early depolarizing GABA controls critical-period plasticity in the rat visual cortex

The inhibitory neurotransmitter GABA can lead to neuronal depolarization during early brain development caused by a shift in intracellular chloride concentration. Here Deidda et al . show that a brief alteration in depolarizing GABA during early development can modulate critical-period plasticity in the visual cortex later in development, and this effect is mediated by perinatal BDNF signaling. Hyperpolarizing and inhibitory GABA regulates critical periods for plasticity in sensory cortices. Here we examine the role of early, depolarizing GABA in the control of plasticity mechanisms. We report that brief interference with depolarizing GABA during early development prolonged critical-period plasticity in visual cortical circuits without affecting the overall development of the visual system. The effects on plasticity were accompanied by dampened inhibitory neurotransmission, downregulation of brain-derived neurotrophic factor (BDNF) expression and reduced density of extracellular matrix perineuronal nets. Early interference with depolarizing GABA decreased perinatal BDNF signaling, and a pharmacological increase of BDNF signaling during GABA interference rescued the effects on plasticity and its regulators later in life. We conclude that depolarizing GABA exerts a long-lasting, selective modulation of plasticity of cortical circuits by a strong crosstalk with BDNF.