Scientists identify chemical in the brain that suppresses unwanted thoughts

A new study has explained how an important chemical within the memory region of the brain helps to suppress unwanted thoughts.

The chemical, known as GABA, is said to be the main inhibitory neurotransmitter in the brain, and its release by one nerve cell can suppress activity in other cells to which it is connected.

To arrive at the findings, the researchers used the ‘Think/No-Think’ procedure to identify a significant new brain process that enables the prefrontal cortex to successfully inhibit our thoughts.

Participants were asked to learn to associate a series of words with a paired, but otherwise unconnected, word, for example; ordeal/roach and moss/north.

In the next stage, they were asked to recall the associated word if the cue is green or to suppress it if the cue is red; in other words, when shown ‘ordeal’ in red, they were asked to stare at the word but to stop themselves thinking about the associated ‘roach’.

Using a combination of functional magnetic resonance imaging (fMRI) and magnetic resonance spectroscopy, the researchers were able to observe what was happening within key regions of the brain as the participants tried to inhibit their thoughts.

Michael Anderson, a professor of the medical research and brain science unit at the University of Cambridge, explained that the ability to control thoughts is beneficial to our well being.

“Our ability to control our thoughts is fundamental to our well being.

“When this capacity breaks down, it causes some of the most debilitating symptoms of psychiatric diseases: intrusive memories, images, hallucinations, ruminations, and pathological and persistent worries.

“These are all key symptoms of mental illnesses such as PTSD, schizophrenia, depression, and anxiety. We wouldn’t be able to survive without controlling our actions.

“We have lots of quick reflexes that are often useful, but we sometimes need to control these actions and stop them from happening. There must be a similar mechanism for helping us stop unwanted thoughts from occurring.”

The study has been published in the Journal Nature communications.