Scientists identified two regions of brain involved in responding to the sweet and bitter taste, which can be modified to provoke different reactions
New study conducted by Columbia University’s Zuckerman Institute aimed to decipher how the identity and valence of sweet and bitter taste were processed at two regions in brain called as the insula cortex and amygdala. The study was conducted and examined on mice, which showed that mice responded to ordinary water as though it was sugar, make bitterness an attractive taste, and turn sweetness into a negative experience. As a part of study, researchers used viral tracing tools and labeled sweet and bitter cortical neurons in green and red. Furthermore, the team mapped their projections brain-wide using one of the latest whole-brain clearing and imaging techniques.
As a result, it was found that sweet and bitter neurons separately projected to two different subregions of amygdala, which is an important brain structure for judging and assigning the value of a sensory stimulus. By switching on or off this cortico-amygdalar circuit, it is possible to change the valence of taste or manually assign a new valence. Valence in this psychological sense refers to the inherent attractiveness or averseness of a particular taste quality. The study concluded that this approach can be used to alter the emotional component of eating certain foods in near future. Furthermore, it might conceivably be used to help people with a range of eating disorders.
“Looking from the long-term view, it may help to address the obesity issue, if we could have a way to change humans’ preference of sugar,” said Dr. Li Wang, a postdoctoral research scientist in the Zuker Lab and the paper’s first author. “In the future, we will expand our research to other brain structures and aim to unravel how these regions drive different aspects of the taste behavioral responses.” A paper describing the work was published in the journal Nature in May 2018.