The culprit behind habitual behavior

There's a neuron for that

The human brain loves shortcuts. First impressions, stereotyping, schemas, and habits are all ways the brain demonstrates laziness. Another way to consider habits is that they free up brain resources that can be used for other things. In many cases, these shortcuts are helpful such as detecting dangerous places or people, helping us understand the world around us, and staying healthy. However, in some cases, habits get out of control and become stronger than our ability to stop them. The negative aspects of strong habits can be seen in people who try to quit smoking or stop eating sugar, and to some extent, body-focused repetitive behaviors (BFRBs). While BFRBs are more compulsory than habitual, researchers are trying to distinguish when a habit becomes a compulsion. If they can find that mechanism, then perhaps they can interrupt it or fix it thereby reversing the compulsion.

Neuroscientists at Duke University believe they found the neuron that serves and “master controller” through experimentation with mice. There is a part of the brain called the striatum, which acts as a traffic signaling system in the brain. One pathway creates action, the other stops it. The researchers trained the mice to develop a lever-pressing habit by rewarding them with sugary treats. What they found is that even when the treats stopped, the mice kept pressing the lever. Looking at the brains of these mice, the “go” pathway of the striatum was incredibly strong, and the complementary timing between the “go,” and the “stop” were off so that the “go” pathway fired off before the stop. The cell that communicates within these pathways is called a “fast-spiking interneuron (FSI)” and serves as the electrical current along these pathways. The FSI neurons in the lever-habit mice were very strong and vibrant, but when researchers interrupted the FSI neurons, the mice seemed to lose the habitual behavior.

Implications

The findings from this research support the adage “practice makes perfect” and points out a specific neuron that may be responsible for increasing the difficulty for breaking habits. The current hypothesis is that compulsion and addiction, according to the researchers who conducted this study, result from corrupted habit-learning mechanisms. As research continues to explore these connections, perhaps pharmacological science will follow with medications that can get the FSI under control.

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