FIGURE 3.

Many Fos-labeled cell nuclei co-express the nuclear protein special AT-rich sequence-binding protein 2 (SATB2), a marker expressed in principal excitatory neurons but not inhibitory neurons. Photomicrographs show fluorescent labeling for Fos-ir (in A, with Cy3) and for SATB2-ir (in B, with Cy2, as well as merged channels in C) in layers 2–3 of the PL. Double-labeled cells are indicated with yellow arrows, whereas those only labeled for Fos (and thus negative for SATB2) are indicated with red arrows (putative inhibitory neurons). Some of the SATB2-labeled cells lacking c-Fos labeling are indicated with green arrowheads. (D) The number of double-labeled cells (SATB2-positive neurons that show Fos labeling) increased throughout the mPFC in the HFD feeding group, and even more so in the exploratory group in pursuit of the HFD (n = 5/group). *p < 0.05, **p <0.005, differences with respect to the control group. ^#p < 0.05, ^##p < 0.005, differences between feeding and exploring groups. Scale bar in A = 25 μm, and also applies to B,C.