Figure 4. Baseline neuronal activity prior to task performance on test day. Percent of neurons active at baseline in the (A) superficial ACC, (B) deep ACC, (C) proximal CA3, and (D) distal CA3. Abbreviations: ACC: anterior cingulate cortex; SH: socially housed; NSH: non-socially housed. Error bars represent standard error of the mean. Dashed lines represent population (test-values) averages obtained from the young cohort.