Figure 9.

Fos⁺, PV⁺, and PNN⁺ cell density after fear conditioning in PND28-PND29 animals. A, B, Fos⁺ cell density was elevated only in the right BLA of males compared with females and fear-conditioned versus control animals. C, Fear treatment increased the density of Fos-activated PV⁺ cells in the left BLA in all animals. D, In the right BLA, fear conditioning activated PV⁺ cells of NB males relative to controls, whereas this was not the case in LB males. Control LB males had significantly increased activation of PV⁺ cells compared with NB males. Thus, LB-reared males in the fear group displayed reduced Fos⁺/PV⁺ cell density compared with their NB counterparts. In NB fear-conditioned animals, males displayed increased PV⁺ cell activity compared with females. E, The density of activated PV⁺ cells expressing PNN was not affected by bedding, sex, or treatment in the left BLA. F, However, in the right BLA, fear conditioning increased the density of PNN around activated PV⁺ cells. Three-way ANOVAs with bedding, sex, and treatment as between-subject factors were performed for each side and followed by simple effects tests to decompose significant interactions. Data are mean ± SEM of n = 5 animals/group (4 sections per amygdala side). *p < 0.05. **p < 0.01. ***p < 0.001.