S. Kollackwalker et Sw. Newman, MATING AND AGONISTIC BEHAVIOR PRODUCE DIFFERENT PATTERNS OF FOS IMMUNOLABELING IN THE MALE SYRIAN-HAMSTER BRAIN, Neuroscience, 66(3), 1995, pp. 721-736
Previous work has shown that mating induces the expression of Fos prot
ein within the chemosensory pathways of the male Syrian hamster brain.
(37) However, it is not known if this pattern of labeling is specific
to mating or the result of social interactions in general. To determin
e the behavioral specificity of activation within these pathways, Fos
immunostaining following mating was compared to that following agonist
ic behavior. Both mating and agonistic behavior are dependent upon che
mosensory cues(15,52,72) and gonadal steroids (reviewed in Refs 64, 65
) and areas belonging to the olfactory and vomeronasal pathways proces
s chemosensory and hormonal information (reviewed in Ref. 48). The res
ults of this study demonstrate both similarities and differences in br
ain activation patterns following these two social behaviors. Agonisti
c behavior increased the number of Fos-immunoreactive neurons within m
ost subdivisions of the medial amygdala, the anteromedial and posteroi
ntermediate bed nucleus of the stria terminalis, the ventrolateral sep
tum and the ventral premammillary nucleus of the hypothalamus in a pat
tern comparable to that observed after mating. This pattern of activat
ion common to mating and agonistic behavior may reflect an increase in
an animal's general state of arousal during social interactions. In c
ontrast, although mating and agonistic behavior both activated neurons
within the caudal subdivision of the medial nucleus of the amygdala,
the anterodorsal level of posteromedial bed nucleus of the stria termi
nalis and the paraventricular and ventromedial nuclei of the hypothala
mus, in these areas either the distribution and/or number of Fos-immun
oreactive neurons differed. In addition, agonistic behavior selectivel
y activated neurons within the anterolateral bed nucleus of the stria
terminalis, the anterior nucleus of the hypothalamus and the dorsal pe
riaqueductal gray, whereas mating alone activated neurons within the p
osteroventral level of posteromedial bed nucleus of the stria terminal
is and the medial preoptic area. No differences were found between dom
inant and subordinate males following agonistic behavior. These observ
ations along with results from other laboratories suggest that mating
and agonistic behavior activate distinct neural circuits.