summary: Researchers focused on a specific group of cells in the periaqueductal gray (PAG) region of the brainstem to identify brain circuits in mice that seek food even when they are not hungry. The discovery reveals how stimulating these cells causes mice to prefer high-calorie foods and engage in food-seeking behavior regardless of hunger.
The study suggests that humans have similar cells, potentially offering new insights into eating disorders. By manipulating the activity of these cells, the researchers demonstrated the ability to increase or decrease food-seeking behavior in mice, pointing to potential future treatments for compulsive eating and anorexia in humans.
Important facts:
- Certain brain cells facilitate the search for food: Researchers found that stimulating VGAT PAG cells in mice triggered food-seeking behavior even in the absence of hunger, highlighting the difference between craving for high-calorie foods and actual hunger. .
- Impact on eating disorders: The existence of similar cells in humans suggests that overactivity or underactivity of this brain circuit may contribute to diseases such as compulsive eating and anorexia, and could be treated. It suggests that there is a sex.
- Compulsive intake of high-calorie foods: Mice activated by these cells were shown to prefer fatty and sugary foods over healthier options, demonstrating the role of this circuit in craving for highly valued foods. Ta.
sauce: University of California Los Angeles
If you find yourself rummaging through the fridge for snacks shortly after eating a hearty meal, your food-seeking neurons may be overactive, rather than having an overactive appetite.
Psychologists at UCLA have discovered circuits in the brains of mice that allow them to crave and seek out food even when they’re not hungry. When this cell population is stimulated, mice begin actively foraging, preferring fatty, pleasurable foods like chocolate over healthy foods like carrots.
Humans have the same type of cells, and this finding, if confirmed in humans, could provide a new way to understand eating disorders.
Report published in magazine nature communicationsare the first to discover cells specialized for food-seeking in a part of the mouse brainstem normally associated with panic but not feeding.
“This region we are studying is called the periaqueductal gray (PAG) and is located in the brainstem. It is very ancient in evolutionary history and is therefore functionally similar in humans and mice.” said corresponding author Avishek Adhikari. , associate professor of psychology at UCLA.
“Our findings were a surprise, but since searching for food is something all animals need to do, it makes sense that food seeking is rooted in such an ancient part of the brain. ”
Professor Adhikari studies how fear and anxiety help animals assess risk and minimize exposure to threats, and his group is investigating how this particular location contributes to fear. I made this discovery while trying to learn how they are involved.
“Activation of the entire PAG region elicits a dramatic panic response in both mice and humans. However, when we selectively stimulate only this particular cluster of PAG neurons, called vgat PAG cells, fear changes. Instead, it triggered foraging and feeding,” Adhikari said.
The researchers injected a virus into the brains of mice that had been genetically engineered to cause brain cells to produce light-sensitive proteins. When a laser is shined into a cell through a fiber optic implant, new proteins convert the light into electrical nerve activity within the cell. A miniature microscope developed at UCLA and attached to the mouse’s head recorded the neural activity of the cells.
When stimulated with laser light, the vgat PAG cells fired, causing the mice to eagerly pursue live crickets and other non-prey food, even if they had just eaten a large meal. This stimulus also causes mice to chase moving objects that are not food (such as ping pong balls, although they did not try to eat them), and also causes mice to confidently explore everything in their enclosure. I urged him to do so.
“The results suggest that the following behaviors are more related to craving than hunger,” Adhikari said.
“Hunger is aversive, and mice typically avoid feeling hungry as much as possible. But they are looking for activation of these cells, and this circuit is not what causes starvation. Rather, it is thought that this circuit causes cravings for high-calorie foods that are highly valued. These cells encourage mice to eat more high-calorie foods even when they are not hungry. There is a possibility that it will.”
Satiated mice with activated VGAT PAG cells highly craved fatty food and were willing to endure foot shock to obtain it, something sated mice do not normally do. That’s true. Conversely, when the researchers injected the mice with a virus designed to produce a protein that reduces cell activity when exposed to light, the mice foraged less, even when they were very hungry.
“When this circuit is active, mice exhibit compulsive eating behavior in response to direct aversive sensations, but when this circuit is not active, mice exhibit compulsive eating behavior even when they are hungry. “This circuitry allows us to avoid the normal hunger pressures of when, what, and how to eat.” said UCLA postdoctoral researcher Fernando Reis, who came up with the idea for the study.
“We built on these findings in new experiments and found that these cells induce the intake of fatty and sugary foods, but not vegetables, in mice. Our findings suggest that this circuit may increase junk food intake.”
Like mice, humans also have vgat PAG cells in their brainstem. When this circuit is overactive, eating may feel more rewarding and you may crave food when you’re not hungry. Conversely, if this circuit is not activated enough, the pleasure associated with eating may be diminished, leading to anorexia. If this food-seeking circuit is discovered in humans, it could potentially be used to treat certain eating disorders.
Funding: This research was supported by the National Institute of Mental Health, the Brain and Behavior Research Foundation, and the National Science Foundation.
About this hunger and neuroscience research news
author: holly over
sauce: University of California Los Angeles
contact: Holly Ober – UCLA
image: Image credited to Neuroscience News
Original research: Open access.
“Feeding control by bottom-up mesencephalic subthalamic pathway” written by Avishek Adhikari et al. nature communications
abstract
Feeding control by bottom-up mesencephalic subthalamic pathway
Research expeditions and foraging that lead to food consumption are extremely important but poorly understood. Because GABAergic inputs to the lateral and ventrolateral periaqueductal gray (l/vlPAG) control such behaviors, we investigated the role of vgat-expressing GABAergic l/vlPAG cells in exploration, foraging, and hunting. was investigated in detail.
Here we show that mouse vgat l/vlPAG cells encode food approach and consumption of both live prey and non-prey. The activity of these cells is necessary and sufficient to induce food search leading to subsequent consumption.
Activation of vgat l/vlPAG cells leads to exploratory foraging and compulsive feeding without altering defensive behavior. Furthermore, l/vlPAG vgat cells are bidirectionally interconnected to several feeding, searching, and surveying nodes, including the zona indeterminate. Remarkably, projections of the vgat l/vlPAG to the zona indeterminate bidirectionally control approach to food leading to consumption.
These data demonstrate that the PAG is not only the final downstream target of top-down exploration- and foraging-related inputs, but also influences these behaviors through bottom-up pathways.
