Figure 2.

Normalized Egr-1 responses in the mesolimbic reward system in (A) female and (B) male white-throated sparrows listening to conspecific male song. For each region, cell density values were divided by the mean tone (control) value to create a normalized Egr-1 fold-induction scale (Jarvis et al., 1995). Values greater than 1 indicate that the mean response to song was greater than the mean response to tones for that region. In the E2-treated females, the response to song was significantly higher than the response to tones in each ROI measured. In the males, we observed selective Egr-1 responses only in TnA. *Significantly greater Egr-1 induction to song than tones; ^† Significant interaction between hormone treatment and auditory stimulus.