The Forebrain Taste System : an Examination of the Effects of Stria Terminalis Knife-cuts on Feeding Behaviour by Richard

Studies examining the etiology of obesity often focus on the relationship between taste, overeating, and the developnlc~r. of obesity. One animal model often used to study obesity, rats with lesions of the ventromedial hypothalamus (VMH) , is popular because the degree of overeating and obesity in that animal is particularly sensitive to the taste qualities of the food the rat eats. The exaggerated sensitivity to taste in VMH rats is termed "finickiness" and is thought to contribute to the hyperphagia and obesity of this animal. The present thesis sought to identify the anatomical locus mediating finickiness. The specific hypothesis examined was that interruption of the stria terminalis (ST), a prominent component of the forebrain taste system and a fibre system descroyed in the typical VMH lesion, produces the finickiness characteristic of the VMH syndrome. A sham feeding paradigm was used to assess finickiness, because sham feeding allows one to measure the extent to which palatability drives feeding. I found t~!at using sham feeding as an index, rats with ST knife-cuts were as finicky as VMH lesioned rats when consuming either sweet sucrose solutions or quinine-adulterated sucrose solutions. However, the degree of finickiness in rats with combined VMH and ST damage was equivalent to the additive effects of VMH and ST damage alone. These results lead to the conclusion