Mechanisms underlying rapid experience-dependent plasticity in the human visual cortex

Visual deprivation induces a rapid increase in visual cortex excitability t hat may result in better consolidation of spatial memory in animals and in lower visual recognition thresholds in humans. gamma -Aminobutyric acid (GA BA)ergic, N-methyl-D-aspartate (NMDA), and cholinergic receptors are though t to be involved in visual cortex plasticity in animal studies. Here, we us ed a pharmacological approach and found that lorazepam (which enhances GABA A receptor function by acting as a positive allosteric modulator), dextrome torphan (NMDA receptor antagonist), and scopolamine (muscarinic receptor an tagonist) blocked rapid plastic changes associated with light deprivation. These findings suggest the involvement of GABA, NMDA, and cholinergic recep tors in rapid experience-dependent plasticity in the human visual cortex.