固执，原来写在基因里
Why do some people find it so hard to change their minds even when faced with new facts? Scientists at MIT may have discovered an important clue hidden in our genes. According to a new study, a change in a specific gene can break a brain circuit responsible for helping us update our understanding of the world. When this system fails, the brain tends to stick to old ideas, ignoring what is actually happening.
The research focused on a gene called grin2a, which previous studies had linked to schizophrenia (精神分裂症). To test the gene’s exact role, researchers designed an experiment with mice. In the experiment, mice had to choose between two levers. One lever offered a small reward but required little effort, while the other gave a much larger reward but required more effort. As the test continued, the researchers made the large reward harder and harder to obtain.
Normal, healthy mice adapted quickly. They realized the task was no longer worth the extra effort and smoothly switched to the easier option. However, mice with the grin2a gene mutation struggled. They kept switching back and forth without a clear plan and took much longer to make a sensible choice. Their brains seemed unable to process the “update” that the situation had changed.
“Normal brains form a belief based on past experience, but they constantly adjust that belief using new sensory input,” explained Tingting Zhou, who led the study. “With this mutation, the brain weighs the old belief too heavily. It fails to use new information to correct the old view, so the mind becomes somewhat detached from reality.”
This brain pathway, which connects two key regions involved in decision-making, acts like a control center for flexible thinking. In a promising twist, when scientists used light-based technology to reactivate this specific circuit in the mice, the animals started behaving normally again and made smarter choices.
Scientists believe this brain circuit might be a common pathway for cognitive difficulties in many patients. The team is now working on finding drugs that could target this pathway to help improve thinking and decision-making in the future.
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