FOS-LIKE IMMUNOREACTIVITY IN THE CAUDAL DIENCEPHALON AND BRAIN-STEM FOLLOWING LATERAL HYPOTHALAMIC SELF-STIMULATION

Fos immunohistochemistry was used to stain neurons in the caudal dienc ephalon, midbrain and hindbrain driven by rewarding stimulation of the lateral hypothalamus (LK). Increases in Fos-like immunoreactivity wer e most pronounced ipsilateral to the site of stimulation and tended to be confined within discrete structures such as the posterior LH, arcu ate nucleus, ventral tegmental area (VTA), central gray, dorsal raphe, pedunculopontine area (PPTg), parabrachial nucleus, and locus coerule us. At least two of these structures, the VTA and PPTg, have been impl icated in medial forebrain bundle self-stimulation. (C) 1997 Elsevier Science B.V.