Figure 4.

Immediate extinction impairment is associated with reduced phosphorylation of the AMPA GluA1 Ser⁸⁴⁵ subunit. Animals were separated into groups (A) balanced for anxiety-like behavior on the elevated plus maze (B), fear conditioned and sacrificed (X) immediately after various context B (CtxB) exposures either 30 min or 24 h after training, with each group showing similar levels of freezing during CtxB exposure (C). Phosphorylation of AMPA GluA1 Ser⁸⁴⁵ was significantly decreased in animals exposed to CS presentations 30 min post-conditioning but not in those with a delayed (24 h) exposure (D) compared with the home cage controls (HC). There were no significant differences in the phosphorylation levels of AMPA GluA1 Ser⁸³¹ (E) or total GluA1 receptor protein (F). Data depicted as percentage of control group ± SEM. *Significant difference (p < 0.05) with HC group; n = 6/group.