<p>This review examines current understanding of the cellular and molecular mechanisms of visual perceptual learning. Evidence is presented supporting the view that perceptual learning is based on long-term synaptic plasticity in the neural networks of the primary visual cortex. Current animal models of perceptual learning, such as stimulus-dependent learning and reinforcement learning, are discussed. The review also substantiates the use of the visual cortex (in particular of rodents) as a model for in vivo studies of the general mechanisms of learning and memory. Work using this approach has provided convincing demonstrations of the roles of homo- and heterosynaptic plasticity in the long-term modifications of sensory responses in the visual cortex. Data obtained in the visual response plasticity model can be extrapolated to the general mechanisms of learning and memory, including going beyond perceptual learning alone.</p>