Your neural reward system and its relationship to drug addiction and obesity.

The reward system in our brain provides us with feelings of pleasure and happiness that occur when dopamine, a type of neurotransmitters (chemical substances that acts as a signal), is released. Due to this desire to feel pleasure and happiness , we are more motivated to go after things that provide us with these feelings. Consequently, this motivation for pleasure is a contributor to drug addiction as well as obesity.

Cocaine is an example of a drug that affects the reward system. As cocaine was sniffed by the participants in the experiment conducted by McGill University Health Centre and McGill University, the amount of dopamine released increased. As the increase of dopamine led to the increase of pleasure and happiness, drug users then desired the pleasant feelings again which could have led to a desire for more cocaine resulting in an addiction. The researchers correlated the “intensity of the reward-circuit response” to the “increased susceptibility to addiction.” What is surprising is that drugs are not the only things that affect our neural reward system. Sugars and, recently discovered, lipids also influences our neural reward system.

Photo courtesy by drugabuse.gov
Photo courtesy by drugabuse.gov

Can we all agree that most of the time, it is easier to get up to get a snack when the snack is chocolate versus when it’s a healthy snack? The motivation that we have to go get chocolate is due to the dopamine, triggered to release by the sugar in chocolate onto our reward system. The pleasurable feeling created when food is consumed motivates us to eat more; however as triglycerides, fat substances in food, build up in our brain, the motivation to physically get more food reduces. This was proven by a group of researchers who induced small amounts of lipids into brains of mice in order to mimic a good meal consumed. As the amount of lipids increased, the physical motivation to push a lever for food decreased. This stopped the mice from eating. Removing the enzyme from the reward circuit of the brain that breaks down these triglycerides led to a continuous increase in food uptake which may have led to obesity. 

As more research slowly display the correlation between increases in dopamine release and drug addictions as well as the role our reward system play in what we eat, further steps can then be identified to tackle issues within these areas of concern. 

Sources:

http://www.sciencedaily.com/releases/2014/04/140415084200.htm – Obesity: Are lipids hard drugs for the brain?

http://www.sciencedaily.com/releases/2011/08/110830193855.htm – Faulty signaling in brain increases craving for sugar and drugs

http://www.sciencedaily.com/releases/2009/05/090519134706.htm – Cocaine: Perceived as a reward by the brain?

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