How Does The Brain's Ability To Filter Distractions Shed Light On Addiction?

By John Lavitt 11/06/15

New research shows how addiction hijacks the brain so it can only focus on getting high.


In a recent study, researchers discovered that the thalamus region of the brain may play a critical role in the filtering of distractions.

Published in Nature and partially funded by the National Institutes of Health (NIH), the study opens the door to understanding how defects in the thalamus generate some of the symptoms experienced by patients with autism, attention deficit hyperactivity disorder (ADHD), and schizophrenia. Moreover, the findings provide insight into how the disease of addiction hijacks the brain’s capacity to focus on anything beyond the need to get high over and over again.

Over three decades ago, legendary researcher Dr. Francis Crick expressed the belief that the thalamus “shines a light” on regions of the prefrontal cortex (PFC), readying them for whatever task is at hand. Dr. Crick is best remembered for being the co-discoverer with James Watson in 1953 of the structure of the DNA molecule. He believed that once the light of the thalamus illuminates the PFC, however, the rest of the brain’s circuits are left in darkness.

“We typically use a very small percentage of incoming sensory stimuli to guide our behavior, but in many neurological disorders the brain is overloaded,” said Dr. Michael Halassa, the study’s senior author and an assistant professor at New York University’s Langone Medical Center. “It gets a lot of sensory input that is not well-controlled because this filtering function might be broken.”

To study the attention mechanism, Dr. Halassa’s team designed a test that challenged mice to ignore distractions. The study discovered that PFC neurons affect the mouse brain, tuning them to sights and sounds by sending signals to inhibitory thalamic reticular nucleus (TRN) cells located deep inside the brain. The research suggested that TRN played a critical role in filtering out stimuli that is not considered important.

Dr. Halassa proposed that, “With this new technique, we can actually watch how circuit problems in the mouse thalamus may lead to problems with concentration that underlie certain neuropsychiatric disorders in humans.”

Although the research might provide a mechanistic explanation of Francis Crick’s theory of the thalamic searchlight, it could also explain the razor-sharp focus that takes over an addict in the depths of their addiction.

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Growing up in Manhattan as a stutterer, John Lavitt discovered that writing was the best way to express himself when the words would not come. After graduating with honors from Brown University, he lived on the Greek island of Patmos, studying with his mentor, the late American poet Robert Lax. As a writer, John’s published work includes three articles in Chicken Soup For The Soul volumes and poems in multiple poetry journals and compilations. Active in recovery, John has been the Treatment Professional News Editor for The Fix. Since 2015, he has published over 500 articles on the addiction and recovery news website. Today, he lives in Los Angeles, trying his best to be happy and creative. Find John on Facebook, Twitter, and LinkedIn.