Motivated social behaviors such as mating are controlled by a complex
network of limbic nuclei. Concepts of network organization derived fro
m computational neuroscience may aid our understanding of the links be
tween the neuroanatomical circuitry and what is represented by the ana
tomy. Research in my laboratory uses mating behavior in the male Syria
n hamster as a model to elucidate how chemosensory and steroid cues ar
e integrated in the brain. An interaction of odors and hormones is req
uired for mating in this species. These two essential stimuli are tran
smitted through separate parallel pathways in the limbic system. The f
unctional organization of the hamster mating behavior circuit is chara
cterized by distributed representation, divergent and convergent neura
l pathways, and recurrent feedback. Odors and hormones have different
modes of action on this neural network. While chemosensory cues stimul
ate the input units of the network, steroids facilitate behavior throu
gh the hidden units. In this manner, steroids appear to create a permi
ssive environment for subsequent activation by odor cues. (C) 1997 Aca
demic Press.