Figure 3.

Visual cortex-dependent consolidation of enhancement. A, Necessity of testing OKT to consolidate P15–P25 experience-dependent enhancement. Suspending testing from P25 to P45 (shading) resulted in a drop from maximal to baseline values. B, Sufficiency of testing OKT after P25 to consolidate enhancement. The graph shows the effect of uninterrupted testing from P15 to P25, P27, P28, P29, P30, P31, and P33, followed by a period without testing until P45. Testing up to P27 was not able to consolidate and maintain enhanced thresholds, whereas testing thereafter was. Testing up to P28/P29 was able to rescue intermediately enhanced function. Data are fit (black line) with a sigmoidal logistic curve centered at 28.4 d. C, Bilateral aspiration of visual cortex in animals with daily testing from P15 to P30 (P15→; filled circles) and from P25 (P25→; open circles). Thresholds in P15→ animals dropped to baseline values after the lesions, whereas thresholds in P25→ were unaffected. Right, Superimposed traces of the lesions from animals in the left panel show that lesions in both groups were centered in V1. D, Treatment with muscimol-releasing Elvax reduced thresholds of enhanced animals to near baseline (P15→; filled circles) but not in naive, unenhanced animals (Naive; open diamonds). Sham surgery in previously enhanced animals did not affect thresholds (Sham; open diamonds; n = 2), nor did removal of Elvax. Right, Representative brain of a muscimol–Elvax-treated animal plotted in the left panel (see supplemental Fig. 2, available at www.jneurosci.org as supplemental material).