Taste Evoked Dopamine and Norepinephrine Track Liking in the Human Amygdala

Abstract

Attributing value to taste depends on the integration of central gustatory signals with reward-related computations. There is strong evidence that the amygdala is a site where such integration occurs. For example, the amygdala has strong reciprocal connections between primary gustatory cortex1,2, gustatory thalamus3,4, and brainstem5. Functional evidence suggests that topographically distinct regions of the gustatory cortex that encode sweet and bitter sensation in rodents project to the amygdala1. Further, human fMRI studies reliably report amygdala activation to taste stimuli6–8, and lesions to the amygdala impair preferences for food cues in humans9. While electrophysiological recordings from human amygdala reveal food-specific valuation encoding in a preference task10, little is known about the neurochemical dynamics in this region. Here we used a novel technology that allows neurochemical measurements on depth electrodes used during standard of care in epilepsy monitoring to measure dopamine (DA) and norepinephrine (NE) in the amygdala while people (n = 3) consumed beverages with varying amounts of fat and sugar. We found that DA and NE fluctuations differed by drink condition. Further analysis revealed that DA increases were associated with drinks with high liking ratings, while NE increases were associated with drinks with low liking ratings. Collectively, these findings demonstrate our capacity to monitor sub-second DA and NE signaling in the human amygdala during food intake and represent a first-of their kind test of the translatability of key findings from animal models.

Keywords: Reward, dopamine, norepinephrine, amygdala, human electrochemical recording