Figure 3. Temporal release of GABA during eyelid conditioning.

Microdialysis was performed through the cerebellar cortex and interpositus nuclei on rats during training in the delay eyelid conditioning task. The time window of GABA release once eyelid conditioning starts can be observed on day 1 (A; N=5 condition, 4 pseudocondition), day 2 (B; N=5 condition, 4 pseudocondition), day 3 (C; N= 4 condition, 3 pseudocondition), day 4 (D; N=4 condition, 3 pseudocondition) and day 5 (E; N= 4 condition; 4 pseudocondition).. GABA release was significantly greater in the conditioning group on day 1 compared to days 2, 3 and 5 (p<0.05). Peak magnitude of release increases over time and the time frame of the response sharpens so that GABA release is sharply timed with the performance of CR’s by day 3 and sharpens further up to day 5. Data are expressed as percent of baseline (% baseline) (y-axis). Black squares represent conditioning, open squares represent pseudoconditioning. (F) Area under the curve representation of GABA release for each day of training during eyeblink conditioning. As was observed with NE, the conditioning group resulted in significantly higher AUC for GABA on all days except day 5, when compared to the pseudoconditioning group (Ps-Cd) (p<0.05), suggesting that the GABA release is associated with learning of the conditioned response. The solid bar underneath the curves indicates the time when the rats were receiving training trials.