Fig. 4

Sex differences in zif268 activation in the brain, and correlations with fear response. Photomicrographs of zif268 immunoreactivity in the frontal cortex (A) and in the dorsal hippocampus (B) in male (left) and female rats (right). Mean (± SEM) density of zif268-ir cells in the frontal cortex (C) and in the dorsal hippocampus (D). Females, compared to males, had greater density of zif268-ir cells in the anterior cingulate cortex (ACC), in the prelimbic cortex (PrL) and in the dorsal CA1. *Indicates p < 0.05. Heat maps generated based on correlations coefficients between the amount of freezing and activated cells (zif268-ir) in different regions of the limbic system (E). Males and females had significant correlations of zif268-ir cell density in different brain regions with the percentage of freezing (*indicates correlations with p < 0.05). There were significant sex differences in the correlations between the percentage of freezing and the density of zif268-ir cells in four different brain regions (Green boxes indicates significant sex differences with p < 0.05). Scatter plots for correlations between the percentage of freezing and the density of zif268-ir cells in the dorsal CA1 (dCA1) (F) and in the lateral dorsal striatum (lDS) (G), and correlations between the discrimination index on the last trial day and the percentage of IdU/zif268-ir cells in the dorsal dentate gyrus (H) in males (blue) and females (red)