Figure 1.

Group I mGluRs are necessary for metaplastic inhibition of spinal learning. Unshocked subjects demonstrated typical spinal learning, increasing flexion duration over the 30 min testing interval (A, F). Brief exposure to uncontrollable shock produced a deficit in spinal learning that was apparent at test at 24 h (A, F). Antagonists to the group I mGluRs, mGluR1 (CPCCOEt in 100% DMSO) (A–E) or GluR5 (MPEP in 0.9% saline) (F–J) restored spinal learning in dose-dependent manner. A–D and F–I depict performance over time; E and J depict group means. The shaded region represents SEM over time; error bars represent SEM for group means (n = 6 subjects/group for CPCCOEt; n = 8 subjects/group for MPEP). *p < 0.05 from unshocked.