The gut, the brain, and addiction

Speaker: Dr. Ivan de Araujo, D.Phil from Yale University

Dr. de Araujo is an Associate Professor from Yale University in the John B. Pierce Laboratory. The goal of his lab is to define the sensorimotor circuitry that controls feeding programs. In 2008 work published in Neuron, Dr. de Araujo showed that taste alone is not enough to communicate the reward value of sugar; he knocked out the trpm5 taste receptor in mice to create a taste blind mouse, but found that mice still tend to prefer sugar after a few hours.

From there, he studied the brain regions that encode for this reward. He found that reward behavior can be abolished by inhibiting the mesolimbic and nigrostriatal brain dopamine pathways. He found that intake of sweeteners activates the ventral striatum while D-glucose activates the dorsal striatum, and that the infusion of nutrients into the gut increases dopamine levels proportional to the amount of calories infused. He then went about delineating the neural circuit driving this response.

Initially, he found that energy is transmitted to the substantia nigra pars compacta to the dorsal striatum to the substantia nigra. Meanwhile, sweetness, in the form of non-nutritive sweeteners, takes a different pathway; it is transmitted to the ventral tegmental area to the ventral striatum to the ventral pallidum. In summary, Dr. Ivan de Araujo has greatly impacted the way we understand the neurobiology of feeding and the reward pathways it elicits.