Researchers at Stony Brook University have made a breakthrough in understanding how signals in the brain can determine an attraction to sweet foods. By using genetic manipulation in a laboratory brain model, they have shown that neurosteroids, signals involved in mood regulation and stress, can reduce the sensitivity and preference for sweet tastes when elevated within the gustatory cortex—a region in the brain most involved with taste. Their findings, published in Current Biology, shed light on the complex relationship between brain activity, taste preferences, and eating habits.
Senior author Arianna Maffei, Ph.D., explains that studies in humans suggest that food preferences can influence eating habits, with decreased sensitivity to taste often leading to overconsumption and potentially obesity. However, measuring changes in brain activity in humans is challenging due to technological limitations. Therefore, the researchers turned to lab mice, whose brain activity can be accurately monitored while measuring their taste preferences.
The murine model used in the study focused on the effect of the neurosteroid allopregnanolone, which is known to be elevated in people affected by obesity. This neurosteroid modulates brain activity by increasing inhibitory circuits mediated by a specific type of GABA receptor. The researchers demonstrated that these GABA receptors are present in excitatory and inhibitory neurons in the gustatory cortex.
By infusing allopregnanolone locally into the gustatory cortex of the mice to activate neurosteroid-sensitive GABA receptors, the researchers were able to reduce the model’s sensitivity and preference for sweet taste. They also used genetic tools to remove these receptors locally, specifically in the gustatory cortex, which completely eliminated the preference for sweet taste over water.
Maffei explains that the reduced sensitivity and preference for sweet taste was even more pronounced when the receptors were selectively removed only from inhibitory gustatory cortex neurons. This manipulation made the mice practically unable to distinguish sugared water from plain water. The study confirmed that a specific type of GABA receptor is crucial for fine-tuning sensitivity and preference for sweet taste.
The researchers are now investigating whether neurosteroids only regulate sweet taste sensation or if they also influence the perception of other tastes. Additionally, they aim to understand how changes in taste sensitivity impact eating behavior. Overall, this study provides valuable insights into the role of the mammalian brain in shaping taste experiences and highlights a specific signal in a specific brain region that is essential for sensitivity to sweet taste.
For more information, you can refer to the study published in Current Biology by Priscilla E. Yevoo et al, titled “Modulation of sweet preference by neurosteroid-sensitive, δ-GABAA receptors in adult mouse gustatory insular cortex” (DOI: 10.1016/j.cub.2025.01.035).
This research was conducted at Stony Brook University. For further details, you can visit their official website.
