You’re on a diet, but the
aroma of popcorn in the movie theater lobby triggers a seemingly irresistible
craving.
Within
seconds, you’ve ordered a tub of the stuff and have eaten several handfuls.
Impulsivity,
or responding without thinking about the consequences of an action, has been
linked to excessive food intake, binge eating, weight gain and obesity, along with
several psychiatric disorders including drug addiction and excessive gambling.
A
team of researchers that includes a faculty member at the University of Georgia
has now identified a specific circuit in the brain that alters food
impulsivity, creating the possibility scientists can someday develop
therapeutics to address overeating.
The team’s findings were
published recently in the journal Nature Communications.
“There’s
underlying physiology in your brain that is regulating your capacity to say no
to (impulsive eating),” said Emily Noble, an assistant professor in the UGA
College of Family and Consumer Sciences who served as lead author on the paper.
“In experimental models, you can activate that circuitry and get a specific
behavioral response.”
Using
a rat model, researchers focused on a subset of brain cells that produce a type
of transmitter in the hypothalamus called melanin concentrating hormone (MCH).
While
previous research has shown that elevating MCH levels in the brain can increase
food intake, this study is the first to show that MCH also plays a role in
impulsive behavior, Noble said.
“We
found that when we activate the cells in the brain that produce MCH, animals
become more impulsive in their behavior around food,” Noble said.
To
test impulsivity, researchers trained rats to press a lever to receive a
“delicious, high-fat, high-sugar” pellet, Noble said. However, the rat had to
wait 20 seconds between lever presses. If the rat pressed the lever too soon,
it had to wait an additional 20 seconds.
Researchers
then used advanced techniques to activate a specific MCH neural pathway from
the hypothalamus to the hippocampus, a part of the brain involved with learning
and memory function.
Results
indicated MCH doesn’t affect how much the animals liked the food or how hard
they were willing to work for the food. Rather, the circuit acted on the
animals’ inhibitory control, or their ability to stop themselves from trying to
get the food.”Activating this specific pathway of MCH neurons increased
impulsive behavior without affecting normal eating for caloric need or
motivation to consume delicious food,” Noble said. “Understanding that this
circuit, which selectively affects food impulsivity, exists opens the door to
the possibility that one day we might be able to develop therapeutics for
overeating that help people stick to a diet without reducing normal appetite or
making delicious foods less delicious.”
Journal article: https://www.nature.com/articles/s41467-019-12895-y
Source: https://myfusimotors.com/2019/12/13/researchers-discover-brain-circuit-linked-to-food-impulsivity/
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