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taylorvich [soylentnews.org] writes:

https://medicalxpress.com/news/2025-03-cravings-food-neurons-amygdala-play.html [medicalxpress.com]

To ensure we get the calories and hydration we need, the brain relies on a complex network of cells, signals, and pathways to guide us when to eat, drink, or stop. Yet, much about how the brain deciphers the body's needs and translates them into action remains unknown.

In a new study published in Nature Communications, researchers from the Max Planck Institute for Biological Intelligence, in collaboration with the University of Regensburg and Stanford University, have identified specific populations of neurons in the amygdala—an emotional and motivational center of the brain—that play a key role in this process.

These specialized "thirst" and "hunger" neurons operate through distinct circuits, influencing the drive to eat or drink. The study, which was carried out in mice, sheds new light on the amygdala's role in regulating our nutritional needs and may offer insights into eating disorders and addiction.

The amygdala, a brain region often linked to emotions and decision-making, also plays a key role in shaping our desire to eat and drink. Earlier research led by Rüdiger Klein's group at the Max Planck Institute for Biological Intelligence revealed that neurons in the central nucleus of the amygdala connect food to feelings—pairing tasty meals with positive emotions, associating bad food with aversion, and suppressing appetite when nausea sets in.

The team also demonstrated that changing the activity of these neurons can alter behavior, prompting mice to eat even when they are full or feeling unwell.

Building on these findings, the new research has detailed distinct groups of neurons in the same central region of the amygdala that respond specifically to thirst and others that respond to hunger, guided by a complex web of molecular cues.

"One of these groups of neurons is solely dedicated to regulating the desire to drink, the first 'thirst neuron' that has been identified in the amygdala," explains Federica Fermani, who led the study. "When we activated these neurons, the mice drank more, and when we suppressed their activity, the mice drank less.

"We also identified another group of neurons in the same region of the amygdala that drives thirst but also plays a role in regulating hunger. These findings highlight how some neurons show remarkable specialization for specific behaviors, while others have more general roles in guiding food and drink choices."

To explore how neurons in the central nucleus of the amygdala regulate drinking and eating, the researchers used advanced genetic tools to study brain activity in mice during hunger, thirst, and when they were already full and hydrated. One method, called optogenetics, allowed the team to activate specific neurons using light-sensitive proteins and a laser precisely tuned to trigger those cells.

They also used approaches to silence the neurons, observing how their absence influenced the mice's tendency to eat or drink. By combining this with new methods that enable the monitoring of individual neurons across multiple brain regions, the researchers mapped where these neurons receive information and identified other brain regions they communicate with.

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