Fos immunoreactivity in the rat forebrain induced by electrical stimulation of the dorsolateral periaqueductal gray matter

Abstract

Electrical stimulation of the dorsolateral periaqueductal gray (dlPAG) matter induces panic- or fear-like responses with intense emotional distress and severe anxiety. In this study, we evoked panic-like behaviour by dlPAG stimulation and evaluated the effect on neuronal activation in different brain regions. The number of c-Fos immunoreactive (c-Fos-ir) cells was measured semi-quantitatively through series of stained rat brain sections. Our results demonstrate strong neural activation in the medial prefrontal cortex, orbital cortex, anterior olfactory nuclei, secondary motor cortex, and the somatosensory cortex. Moderate increases in the number of c-Fos-ir cells were detected in various regions, including the hypothalamus, amygdala, and striatum. Additionally, there was mild expression of c-Fos-ir cells in the hippocampus, thalamus, and habenula regions. In conclusion, we have shown that deep brain stimulation of the dlPAG produced a distinctive pattern of neuronal activation across forebrain regions as compared to the sham and control animals. © 2009 Elsevier B.V. All rights reserved.