By Xu Sangyu
One of the main functions of the brain is to find food; food fuels the brain, but also affects it in many other ways. For our second talk in the Brain & Body Seminar Series on November 23, Associate Professor Monica Dus (University of Michigan) shared her research on the dramatic effects of high-sucrose diet (HSD) on peripheral and central processing of sweet taste and on satiety.
The Dus lab demonstrated that HSD blunted sucrose perception and increased feeding in a simple model organism, the vinegar fly. They also observed a similar phenomenon – dulled sucrose detection as a result of HSD – in rats. The conservation of the behavioural phenomenon and cellular mechanism is striking, though fortunately this mammalian effect was reversible (phew!). In the fly, the dulled sugar perception in the periphery translated to reduced activities in a group of dopamine neurons, PAM-β’2, leading to the conclusion that HSD weakened satiation. Indeed, HSD-impaired PAM-β’2 neurons are also in turn less effective in reinforcing association between sucrose reward and odor dues. Dr. Dus invoked the satiety cascade to explain that during a meal, we mainly rely on sensory cues to learn about the nutritional value of food, and we use that to predict how much we need to eat. While post-ingestive responses do exist, they are too slow for this purpose. Neuronal changes due to HSD alter the ability to make that prediction and hence the decision on how much to eat before post-ingestive responses manage to kick in. To repair or prevent this uncoupling between the sensory experience of food and the feeling of satiety in the brain, Dr. Dus advocated mindful eating as a solution to (re)connect the two. This talk certainly made some of us think twice about that afternoon bubble tea!
The Brain & Body Seminar Series continues with the next instalment in January. We are looking forward to Prof. Didier Stainier, who will give an in-person talk about developmental control of metabolism. The details of the seminar will be sent out closer to the date. Please stay tuned!
If you missed the seminar, the video recording can be found here:
Brain & Body Seminar Series – Monica Dus Recording
The recording is accessible to SfN.SG members. Please write to Sangyu (email@example.com) to receive the passcode.