Brain and Environment Interaction: Neuroplasticity of the Visual Cortex and the Roles of Sensory Deprivation, Sleep, and Dreams.

The adult visual cortex, once thought to be rigid and unchangeable, retains some capacity for neuroplastic change, which can be influenced by environmental factors such as visual deprivation. The Defensive Activation Theory (DAT) proposes that dreaming during rapid eye movement sleep helps prevent loss of visual function during the visual deprivation that occurs nightly. This review examines evidence for visual cortical plasticity across the human lifespan and the roles of sleep and dreaming in mediating that plasticity, concluding that adult neuroplasticity contributes to functional outcomes and that sleep plays a mediating role.

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Abstract

Neuroplasticity refers to the tendency of the nervous system to change structurally and functionally due to experience. The adult visual cortex was historically presumed rigid and unchangeable. However, recent research has identified residual neuroplasticity in the visual cortex extending into adulthood, which may be mediated by environmental factors including visual deprivation. Eagleman and Vaughn proposed the Defensive Activation Theory (DAT) in 2021, which posits a role for rapid eye movement sleep (REMS)-related dreaming in preventing neuroplastic loss of visual function during the extended periods of visual deprivation that occur during sleep. We reviewed research examining the extent of visual cortical plasticity across the human lifespan and the roles of sleep and dreaming regarding this neuroplasticity, providing further discussion of the DAT and potential areas for future investigation. Neuroplasticity in adulthood can contribute to functional outcomes, and sleep appears to play a role in mediating this neuroplasticity.