Functional connectivity among limbic brain areas: Differential effects of incubation temperature and gonadal sex in the leopard gecko, Eublepharis macularius
Jt. Sakata et al., Functional connectivity among limbic brain areas: Differential effects of incubation temperature and gonadal sex in the leopard gecko, Eublepharis macularius, BRAIN BEHAV, 55(3), 2000, pp. 139-151
The neural basis of individual differences in behavior has been studied pri
marily by analyzing the properties of specific neural areas. However, becau
se of the organization of the nervous system, it is also plausible that dif
ferences in behavior are mediated by differences in the interactivity or fu
nctional connectivity among brain nuclei in particular neural circuits. In
the leopard gecko, Eublepharis macularius, the temperature of the egg durin
g incubation not only determines gonadal sex, but also shapes the sociosexu
al behaviors, reproductive physiology, and hormone sensitivity of adult ani
mals. In this study the effects of both incubation temperature and gonadal
sex on functional connectivity among limbic brain areas were examined. Func
tional connectivity was assessed by analyzing covariance patterns in metabo
lic capacity, as revealed by quantitative cytochrome oxidase histochemistry
. It was hypothesized that incubation temperature and gonadal sex affect th
e propensity to display aggressive or sexual behaviors by altering the func
tional connectivity within relevant neural circuits. The correlations of me
tabolic capacity between the anterior hypo-thalamus and both the septum and
preoptic area were significant only in relatively aggressive individuals,
suggesting that these circuits may regulate the phenotypic variation in agg
ressiveness caused by incubation temperature. The correlations between the
ventromedial hypothalamus and both the dorsal ventricular ridge and septum
were significant only in females, suggesting that these circuits may modula
te female-typical sexual behaviors. Correlations among preoptic, hypothalam
ic and amygdalar areas tended to be distributed across both sexes, suggesti
ng that there may be shared pathways underlying the expression of male-typi
cal and female-typical behaviors. Copyright (C) 2000 S. Karger AG. Basel.