Prior experience enhances plasticity in adult visual cortex

Abstract

Early experiences facilitate learning the same type of information at a later time. Indeed, the brain has a remarkable capacity to adapt to alterations in its sensory environment; this phenomenon is much more pronounced in juvenile animals. In this study, the authors show that in adult mice, the ability to adapt to changes can be improved profoundly if the mouse has already experienced a similar change in its sensory environment earlier in life. The authors used monocular deprivation, which is the standard model to study sensory plasticity in the mouse visual cortex (ocular dominance plasticity). Mice were monocularly deprived at different ages and imaging and multi-unit recordings were used to test how quickly and robustly ocular dominance columns shifted following subsequent bouts of monocular deprivation. They found that a transient shift in ocular dominance, induced by monocular deprivation earlier in life, renders the adult visual cortex highly susceptible to subsequent monocular deprivation many weeks later. Irrespective of whether the first monocular deprivation was experienced during the critical period (around postnatal day 28) or in adulthood, ocular dominance shifts induced by a second monocular deprivation were faster, more persistent, and specific to repeated deprivation of the same eye. The authors conclude that capacity for plasticity in the mammalian cortex can therefore be conditioned by past experience. It suggests a trace of the prior plastic episode, which may be the result of structural of pharmacological memory.—Valérie Biousse