Number of ΔFosB-ir cells in the NAc core and shell is dependent on pubertal testosterone and sexual experience. Number of ΔFosB-ir cells in the NAc core and shell is dependent on pubertal testosterone and sexual experience. A, Brain atlas (Morin and Wood, 2001) representation of a coronal section containing the NAc. B, Photomicrographs of drawn contours of the NAc onto immunohistochemically-treated tissue sections. The NAc included the shell and core. LV = lateral ventricle; ac = anterior commissure. Scale bar = 250 µm. C, In the core, there was an interaction between pubertal testosterone and sexual experience on ΔFosB-ir cells with sexual experienced T@P males having significantly more ΔFosB-ir cells compared to sexually naive T@P males. There were no significant differences in ΔFosB-ir cells as a function of sexual experience within NoT@P males. In the shell, there was a main effect (ME) of sexual experience on ΔFosB-ir cells with sexually experienced males having more ΔFosB-ir expression compared to sexually naive males. Bars represent mean (±SEM); numbers on bars indicate sample sizes. +Interaction between pubertal testosterone and sexual experience, p ≤ 0.05. Kayla C. De Lorme et al. eNeuro 2019;6:ENEURO.0176-19.2019 ©2019 by Society for Neuroscience