Compound complementarities in the study of motivated behavior.

In his classic article, Stellar (1954) proposed that diverse motivated behaviors reflected the activity of excitatory and inhibitory centers in the hypothalamus. His specific and testable ideas provided the theoretical focus for a great deal of fruitful research on the biological bases of behavior for 2 decades. Subsequently, new findings and technical developments again changed the perspective and experimental approaches in behavioral neuroscience. The authors suggest that the modern emphasis on the anatomy and chemical function of neuronal systems has come at the expense of understanding the subcomponents of behavior and the hierarchical levels of integration involved in transforming reflexes into operant acts. Increased attention in the future to the infrastructure of the behaviors being elucidated, when combined with reductionistic studies of neurons, will fulfill the potential contribution to behavioral neuroscience that is implicit in Stellar's article.