Fig. S4.

Model of Arc’s role in controlling the “juvenile” quality of OD plasticity. Various genetic, environmental, and pharmacological manipulations have been shown to promote juvenile-like plasticity in adult visual cortex. It has been proposed that these manipulations cause a general increase in the ratio of excitation (E) to inhibition (I). Here, we propose that the increase in E/I restores juvenile plasticity specifically by allowing the induction of activity-regulated genes such as Arc. Increased Arc expression promotes activity-dependent synaptic depression that underlies juvenile OD plasticity. *Significantly lower than contralateral eye at baseline.