Running Head: DEEP BRAIN STIMULATION AND TASTE REACTIVITY 1 Effects of Deep Brain Stimulation on Taste Reactivity in the Central Medial Nucleus of the Amygdala by

Alterations to the hedonic value of food could be an underlying cause of obesity. To assess the hedonic impact, a taste reactivity test, which is sensitive to the palatability of food and dissociable from sensory processes, was used. In this preliminary study, we measured hedonic and aversive taste reactions to oral infusions of sucrose, water and quinine during deep brain stimulation of the central medial nucleus of the amygdala (CeM). It was hypothesized that stimulation of the CeM will decrease the hedonic impact to a sucrose solution while increasing the aversive impact to a quinine solution. Since this was a preliminary study with a small sample size, no strong conclusion can be made. However, the results hint that an aversive state was experienced by the rats. An increase in aversive taste reactions and a decrease in hedonic reactions were observed. During taste infusions, an increase in aversive responses to sucrose was seen. Even the small number of positive facial reactions to water decreased. These findings suggest deep brain stimulation in the central amygdala may be creating an overall aversive state in the rat. With further work, an experiment such as this can be useful in understanding how brain stimulation could be used as a treatment for morbid obesity.