Can Unwanted Thoughts Be Prevented?

Unwanted thoughts that keep popping up are never pleasant, but a study by researchers from the Universities of Cambridge, Granada and Utah found a chemical already present in the brain that can stop any unwelcome reflection.

The chemical, known as hippocampal GABA, is able to overpower the cell activity around it when released from a neuron.

The study found that people with the highest levels of GABA – found in the brain’s memory center, the hippocampus – were able to easily avoid any undesirable thoughts. Michael Anderson, the study’s lead author and professor at the University of Cambridge, said when the inability to dodge unwanted thoughts becomes more frequent, it can cause devastating effects.

“When this capacity breaks down, it causes some of the most debilitating symptoms of psychiatric diseases – intrusive memories, images, hallucinations, ruminations and pathological persistent worries,” Anderson said to BBC.

To better understand how the chemical functions, the researchers asked participants to complete an activity that paired a series of words with other terms that were unrelated, such as ‘moss’ and ‘north’ or ‘roach’ and ‘ordeal.’ After reviewing the term pairings, participants were asked to respond to red and green signals.

If participants saw a green signal, they were asked to remember associated pairs; if it was red, they were asked to suppress any associations. By using functional magnetic resonance imaging (FMRI) and magnetic resonance spectroscopy to measure blood flow and chemical changes within the brain, the researchers were able to see how the participants’ brains reacted to the activity.

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The researchers were then able to identify GABA as the key player in suppressing unwanted thoughts. Anderson said the study helps to narrow generalizations about brain functions.

“What’s exciting about this is that now we’re getting very specific,” Anderson said. “Before, we could only say ‘this part of the brain acts on that part,’ but now we can say which neurotransmitters are likely to be important.”

The study stated that it has future implications for those suffering from a wide variety of mental illnesses, including post traumatic stress disorder (PTSD), schizophrenia and more. Anderson said he believes the study could help to open new avenues for treating mental illnesses.

“Most of the focus has been on improving the functioning of the prefrontal cortex,” he said. “Our study suggests that if you could improve GABA activity within the hippocampus, this may help people to stop unwanted and intrusive thoughts.”