Figure 2.

Mean (±SEM) percentage total neurons (sytox; green) that were positive for Arc mRNA (red) in a given cellular compartment, and representative fluorescent images. A, CA1 region of DH. Animals showed a significant increase in double-labeled cells (gray) in the DH, regardless of whether or not the environment was fear inducing (Immediate vs Delay). B, Cells in the BLA were only double labeled if animals were afraid (Delay group). C, Arc expression in PL cortex revealed overlap in neuronal ensembles involved in both events, which was further enhanced in fear-conditioned rats. D, Levels of Arc expression in the IL cortex showed no compartmental differences. ***p < 0.001, **p < 0.01, *p < 0.05.