Fig. 3. Pharmacological reversal of plasticity at excitatory synapses in DLS, but not DMS or motor cortex, disrupts execution of the learned skill.

(A) Representative expert animals injected with ZIP, an inhibitor of an enzyme necessary for maintaining synaptic plasticity at excitatory synapses, in either motor cortex, DMS or DLS (see Results, Materials and Methods, and fig. S5). Shown are heatmaps of probability distributions of IPIs and ITIs before and after ZIP injections (5 days post-surgery recovery between pre and post). (B) Population results for manipulations as in (A), normalized to performance before the manipulation. Control animals received injections of retrobeads in vehicle into DLS. Left: Fraction of trials with IPI close to target (700 ms ± 20%). Right: Fraction of trials with ITI above threshold (1.2 s) (see fig. S5). (C) Distributions of durations between lever-presses for animals shown in (A). Pre-ZIP, last 2000 trials before ZIP; post-ZIP, first 2000 trials after ZIP. (D) JS divergence as a measure of dissimilarity between IPI and ITI distributions in the conditions in (A). For statistical details, see table S3 and fig. S3C for further comparison of the manipulation effects. Bars show means, dots show individual animals, and error bars show SEM. **P < 0.01.