Confocal images of a transverse section of T6 spinal cord segment, showing c-Fos (FITC) and GFAP (rhodamine) labeling in the IML ( A ) and the lfu ( B ). Arrowheads: neuronal nuclei, indicating isolated nuclear c-Fos-IR not surrounded by fibrillary GFAP-IR. Arrows: neuroglial nuclei, indicating nuclear c-Fos-IR in close proximity to fibrillary GFAP-IR. (A) Concentrated c-Fos-positive neurons with large round nuclei (arrowheads) in the IML. The neuroglial cells have small slender nuclei (arrows; one at the upper right is only faintly labeled for c-Fos-IR). (B) c-Fos-positive neuroglial cells in the lfu. Here, nuclear c-Fos-IR is intimately embedded in GFAP-IR (arrows). Scale bars = 10 μm in (A, B).