Motivation, emotion, feeding, drinking, sexual behaviourFos-like immunoreactivity in the periaqueductal gray of rats exposed to a natural predatorCanteras, Newton Sabino1,2; Goto, Marina1Author Information 1Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, Av. Prof. Lineu Prestes 1524, São Paulo, Brazil CEP 05508-900. 2Corresponding Author: Newton Sabino Canteras ACKNOWLEDGEMENTS: We are grateful to Ana Maria Peracoli Campos for preparing the histological material. This work was supported by FAPESP grant 92/05096-8 and CNPq fellowship 300562/93-4 to NSC, and FAPESP fellowship 94/2868-5 to M.G. Received 12 November 1998; accepted 27 November 1998 NeuroReport: February 5th, 1999 - Volume 10 - Issue 2 - p 413-418 Buy Abstract In the present study we examined, in rats exposed to a predator (cat), the distribution of neurons expressing Fos along the continuum formed by the central gray surrounding the caudal pole of the third ventricle and the periaqueductal gray (PAG). After the predatory encounter, a distinct cluster of Fos-immunoreactive cells was observed in the precommissural nucleus. In the rostral two-thirds of the PAG, Fos expression was mostly seen in the dorsomedial and dorsolateral regions. In contrast, at caudal levels of the PAG, most of the Fos-labelled neurons were distributed in the lateral and ventrolateral PAG. These results are discussed and compared with the pattern of the PAG activation after fear conditioned to a context or elicited by aversive foot shock. © 1999 Lippincott Williams & Wilkins, Inc.