Hypothalamic map of stimulation current thresholds for inhibition of feeding in rats

Abstract

The rat hypothalamus was mapped for the purpose of identifying regions at which electrical stimulation caused the feeding behavior of a hungry animal to be inhibited. At each inhibitory site a determination was also made of the minimal stimulation current necessary for the inhibition of feeding. The results indicated that the inhibitory sites with the lowest current thresholds tended to form a discrete cluster in the lateral part of the ventromedial nucleus and the adjacent neuropil bordering it ventrolaterally. A few low thresholds were also found in the anterior hypothalamic area. The higher thresholds formed an orderly ascending gradient radiating away from the ventromedial nucleus and its ventrolaterally situated anatomical projections. In areas related to ascending monoamine pathways, including the lateral hypothalamus, preoptic region, and arcuate nucleus, as well as in the mammillary bodies, stimulation usually failed to suppress feeding behavior. Implications bearing on neuroregulatory models of feeding behavior are discussed.