Changes to the brain’s reward system may drive overeating in mice


IMAGE: A high-fat, high-sugar diet decreases membrane potential (purple, left) and firing rate (purple, right).
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Credit: Gendelis, Inbar et al., JNeurosci 2020

A combination of innate differences and diet-induced changes to the reward system may predispose some mice to overeat, according to research recently published in JNeurosci.

Food is fuel, but the rising levels of sugar and fat in modern diets make the brain treat it as a reward. One brain region called the ventral pallidum (VP) serves as a hub between reward areas and the hypothalamus, a region involved in feeding behavior. Intertwining food and reward can lead to overeating and may be a contributing factor to diet-induced obesity.

Gendelis, Inbar, et al. measured electrical activity in the VP of mice with unlimited access to high fat, high sugar food for several months. Eating the unhealthy diet changed the electrical properties of VP neurons: the membrane voltage and firing rate decreased, making it harder for neurons to send messages to each other. The change was more pronounced in the mice that gained the most weight. The same set of electrical bursts strengthened synapses in weight gainers but weakened them in mice that gained the least weight. These signaling differences may be innate and not caused by the unhealthy diet itself: the same plasticity differences appear between mice with natural high and low food-seeking behavior even without exposure to an unhealthy diet.

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Manuscript title: Metaplasticity in the Ventral Pallidum as a Potential Marker for the Propensity To Gain Weight in Chronic High-Calorie Diet

About JNeurosci

JNeurosci, the Society for Neuroscience’s first journal, was launched in 1981 as a means to communicate the findings of the highest quality neuroscience research to the growing field. Today, the journal remains committed to publishing cutting-edge neuroscience that will have an immediate and lasting scientific impact, while responding to authors’ changing publishing needs, representing breadth of the field and diversity in authorship.

About The Society for Neuroscience

The Society for Neuroscience is the world’s largest organization of scientists and physicians devoted to understanding the brain and nervous system. The nonprofit organization, founded in 1969, now has nearly 37,000 members in more than 90 countries and over 130 chapters worldwide.