Arc also has an important function in the response to visual experience (Table 1). After monocular deprivation in wild type mice, the visual cortex shows depression of deprived-eye responses and potentiation of open-eye responses. The visual cortex of Arc KO mice did not show these changes and also lacked the normal response to the same stimulus given over several days, including a stimulus-selective response potentiation [74], orientation specificity and average spike tuning [56]. Given Arc’s role in mediating homeostatic plasticity, it is also unsurprising that Arc KO mice are deficient in a form of homeostatic plasticity seen in the visual cortex in response to changes in light exposure. After 2 days of dark-rearing, wild type mice show an enhanced mini-excitatory post-synaptic potential amplitude that is reversed upon 2 h of light exposure, and both of these adaptations were absent in KO mice [75].