Researchers discover brain circuit that controls

Researchers discover brain circuit that
controls compulsive overeating and sugar
29 January 2015
behavior, similar to drug addiction. But the major
difference between the two behaviors is that eating
is required for survival, underscoring the need to
tease apart brain circuits involved in compulsive
overeating versus normal feeding to develop safe
and effective therapies. Tye and her team
suspected that a neural pathway from the lateral
hypothalamus to the ventral tegmental area might
play an important role in compulsive overeating
because these brain regions have been implicated
in reward-related behaviors such as eating, sexual
activity, and drug addiction.
Credit: Wikimedia Commons
Compulsive overeating and sugar addiction are
major threats to human health, but potential
treatments face the risk of impairing normal
feeding behaviors that are crucial for survival. A
study published January 29th in the journal Cell
reveals a reward-related neural circuit that
specifically controls compulsive sugar consumption
in mice without preventing feeding necessary for
survival, providing a novel target for the safe and
effective treatment of compulsive overeating in
"Although obesity and Type 2 diabetes are major
problems in our society, many treatments do not
tackle the primary cause: unhealthy eating habits,"
says senior study author Kay Tye of the
Massachusetts Institute of Technology. "Our
findings are exciting because they raise the
possibility that we could develop a treatment that
selectively curbs compulsive overeating without
altering healthy eating behavior."
Compulsive overeating is a type of reward-seeking
To test this idea, Tye and her team used a
technique called optogenetics, which involves
genetically modifying specific populations of
neurons to express light-sensitive proteins that
control neural excitability, and then delivering either
blue or yellow light through an optic fiber to activate
or inhibit those cells, respectively. Activation of the
pathway from the lateral hypothalamus to the
ventral tegmental area caused well-fed mice to
spend more time feeding and increased the number
of times mice poked their nose into a port to receive
a sugar reward, even when they had to cross a
platform that delivered foot shocks to get to the
reward. By contrast, inhibition of the same pathway
reduced this compulsive sugar-seeking behavior
without decreasing food consumption in hungry
mice, suggesting that different neural circuits
control feeding in hungry animals.
In an independent study also published January
29th in Cell, Garret Stuber of the University of North
Carolina School of Medicine and his team similarly
used an optogenetic approach in mice to identify
neurons in the lateral hypothalamus that control
both feeding and reward-seeking behavior. By
imaging the activity of hundreds of individual lateral
hypothalamus neurons as the mice freely explored
an area with food or worked to obtain a sweet
reward, they further uncovered distinct subsets of
neurons that either mediate food-seeking behavior
or respond to reward consumption.
According to Tye, it makes sense that brain circuits
evolved to support binging on scarce, sugary foods
whenever these valuable sources of energy
become transiently available during certain
seasons. But in the winter, it might be adaptive for
separate neural circuits to drive hungry animals to
eat whatever type of food is available but to
consume less overall to ration out limited
"However, in our modern day society, there is no
scarcity of palatable foods, and high-sugar or highfat foods are often even more available than fresh
produce or proteins," Tye says. "We have not yet
adapted to a world where there is an
overabundance of sugar, so these circuits that drive
us to stuff ourselves with sweets are now serving to
create a new health problem. The discovery of a
specific neural circuit underlying compulsive sugar
consumption could pave the way for the
development of targeted drug therapies to
effectively treat this widespread problem."
More information: Cell, Nieh et al.: "Decoding
Neural Circuits that Control Compulsive SucroseSeeking"
Cell, Jennings et al.: "Visualizing hypothalamic
network dynamics for appetitive and consummatory
Provided by Cell Press
APA citation: Researchers discover brain circuit that controls compulsive overeating and sugar addiction
(2015, January 29) retrieved 6 February 2015 from
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