The Hippocampus and Motivation: A Re-Examination

Summary

Evaluation of the literature of the effects on behavior of homeostatic shifts and hippocampal lesions suggest that both conditions produce parallel effects. In both cases, performance is improved on simple tasks and impaired on complex task. The similarity between these effects and the Inverted “U” function is noted and a “behavioral habituation” model was suggested as the mode of hippocampal functioning. This model postulates that in the intact animal, the hippocampus inhibits sensory input during a condition of homeostatic equilibrium and releases inhibition during a disequilibrium. A model is suggested in which the hippocampus modifies or biases responsiveness to events in the environment as a function of the internal homeostatic milieu.