Figure 1.

Exposing resident males to novel male intruders results in upregulation Arc protein expression in AOB IGCs. A, Parasagittal section through the AOB of a C57BL/6J male resident 90 min after being exposed to a BALB/cJ male intruder. Immunofluorescence indicates Arc protein expression. Scale bar, 100 μm. n = 6 animals, 23 sections. GL, Glomerular layer; LOT, lateral olfactory tract. B, AOB section from a control resident that was not exposed to an intruder. n = 3 animals, 12 sections. C, Enhanced view of IGCs in the boxed in area in A. D, Percentage of all cells expressing somatic Arc protein. Wilcoxon–Mann–Whitney test, ****p < 0.0001. Scale bar, 100 μm. E, Normalized anterior–posterior position of Arc-expressing cells in the ICL. Wilcoxon–Mann–Whitney test, ***p < 0.001.