Figure 4.

Training-related increase in phospho-p70s6K is specific to the learned association. Bars represent mean optical density (OD) values (±SEM) expressed as a percentage of control. a, b, There were no changes in total-p70s6K expression after immediate or delayed shock (a), but a significant increase in phospho-p70s6K was seen only in rats that received a delayed shock (b). Immunofluorescence images (20× magnification) from single subjects killed from their home cage (HC) (c) or given a single shock immediately (IMM) or 2 min after placement into the chamber (DLY) are shown. d, e, Although controls (d) received the same shock and stimulus exposure, phosphorylation of the enzyme in the lateral amygdala was seen only in rats that formed new long-term memory for fear conditioning (e) (*p < 0.05).