Introducing the brain: appetite controls in cold weather (Introduction)

by David Turell , Wednesday, August 16, 2023, 19:42 (463 days ago) @ David Turell

Found in the brain:

https://medicalxpress.com/news/2023-08-cold-temperatures-trigger-brain-boost.html

Neuroscientists at Scripps Research have identified brain circuits that make mammals want to eat more when they are exposed to cold temperatures.

"Mammals automatically burn more energy to maintain normal body temperature when exposed to cold. This cold-activated increase in energy expenditure triggers an increase in appetite and feeding, although the specific mechanism controlling this had been unknown. In the new study, published in Nature, the researchers identified a cluster of neurons that work as a "switch" for this cold-related, food-seeking behavior in mice. The discovery could lead to potential therapeutics for metabolic health and weight loss.

***

"Using techniques called whole-brain clearing and light sheet microscopy, the researchers compared the activity of neurons across the brain during cold versus warm conditions. Soon they made a key observation: While most of the neuronal activity across the brain was much lower in the cold condition, portions of a region called the thalamus showed higher activation.

"Eventually, the team zeroed in on a specific cluster of neurons called the xiphoid nucleus of the midline thalamus, showing that activity in these neurons spiked under cold conditions just before the mice stirred from their cold-induced torpor to look for food. When less food was available at the onset of the cold condition, the activity increase in the xiphoid nucleus was even greater—suggesting that these neurons respond to a cold-induced energy deficit rather than cold itself.

"When the researchers artificially activated these neurons, the mice increased their food-seeking, but not other activities. Similarly, when the team inhibited the activity of these neurons, the mice decreased their food-seeking. These effects appeared only under the cold condition, implying that cold temperatures provide a separate signal that must also be present for appetite changes to occur.

"In a last set of experiments, the team showed that these xiphoid nucleus neurons project to a brain region called the nucleus accumbens—an area long known for its role in integrating reward and aversion signals to guide behavior, including feeding behavior."

Comment: it appears that very specific requirement like cold exposure relates to a very specific region in the brain. We knew the brain was specific and generalized in its functions.