Effects of one-stage or serial transections of the lateral olfactory tracts on behavior and plasma testosterone levels in male hamsters.
Bilateral transections of the later olfactory (LOT) in male hamsters at the rostral border of the olfactory tubercle or anterior to the tubercle produced severe deficits in mounting, scent marking, food hoarding and nesting behaviors. There were no impairments of these behaviors following unilateral transections. Cutting of the LOT in two stages, and provision of additional experience in sexual and territorial behaviors during the interval between the first and second transection, did not alleviate the behavioral deficits. Impairments in mounting and scent marking were dissociated in some subjects, indicating individual differences in the hamsters' dependence on chemosensory cues for the regulation of these two types of social behavior. It is suggested that the apparent sparing of behavioral function which has been associated with gradual destruction of nervous tissue is due to the development of alternate mechanisms of response to environmental cues, and may be more difficult when brain damage is in structures which initially process these cues. Although sexual and territorial behaviors in the hamster are dependent on gonadal hormones, the observed impairments of these behaviors could not be explained as indirect consequences of lesion effects on the hypophysiogonadal axis. Circulating testosterone (T) levels in experimental subjects were not different from levels in control (sham-operated) subjects. An inverse correlation was observed between the control subjects' circulating T levels and their incidence of scent marking. A similar correlation was observed between postoperative T levels and preoperative marking rates in experimental subjects, despite the fact that most subjects failed to scent mark after bilateral LOT transections. The latter observation strengthens the inference that the bilateral deficits were independent of changes in basal hormone levels.
D000818:Animals; D001522:Behavior, Animal / Q000502:physiology*; D001931:Brain Mapping; D006224:Cricetinae; D005247:Feeding Behavior / Q000502:physiology; D008032:Limbic System / Q000502:physiology*; D008297:Male; D009425:Nesting Behavior / Q000502:physiology; D009833:Olfactory Pathways / Q000502:physiology; D012726:Sexual Behavior, Animal / Q000502:physiology; D013739:Testosterone / Q000097:blood*
D013739:Testosterone