Brain of "thinkers" is different

Structural differences affect the ability to make quick and accurate decisions

The individual flexibility in balancing fast and accurate responses depends on the strength of the connection between different brain regions: the pre-supplementary motor area (pre-SMA) and the basal ganglia, especially the anterior striatum (green). © MPI for Human Cognitive and Brain Sciences
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How well and quickly we can decide depends on the structure of our brain. Researchers have now found this out with the help of magnetic resonance imaging and behavioral tests on volunteers. As reported in the journal "Proceedings of the National Academy of Sciences, " strong fiber connections between the cerebral cortex and a nucleus at the brain base facilitate making quick and accurate decisions.

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Most of us know what it means to make decisions under time pressure: then we have to intuitively weigh how much accuracy we can do without our decision being too late. There are big individual differences: Some people find the right balance between fast and accurate answers, while others are less efficient. Neuroscientists and mathematical psychologists at the Max Planck Institute for Human Cognitive and Brain Sciences in Leipzig together with colleagues from the Universities of Amsterdam, Bristol and Newcastle (Australia) have now found that individual decision-making behavior is related to structural differences in the brain.

Brain structures under the magnifying glass

For their study, the researchers studied a total of nine subjects using ultra-high-resolution magnetic resonance imaging (MRI) using two different magnetic field strengths of seven and three Tesla. The goal of the seven-tesla MRI was to depict a tiny nucleus in the basal ganglia, the so-called Subthalamic Nucleus. He plays an important role in controlling our actions. The three-tesla measurements were used to calculate the strengths of the connecting fibers between the subthalamic nucleus, the striatum, an important junction in the brain, and areas of the cerebral cortex.

decision tests

In addition to the investigations in magnetic resonance tomography, the subjects participated in behavioral experiments. At the beginning of each test run, they were instructed to either decide very fast or as accurately as possible. "At the touch of a button, the subjects had to assess whether a point cloud was moving to the right or to the left, " explains Birte Forstmann, explaining the course of the experiment. display

Fiber connections crucial

The evaluation of all experiments showed that the strength of the fiber connections between an area in the cerebral cortex and the basal ganglia is decisive. People who can easily find a middle ground between quick and right decisions can show stronger fiber connections than people who struggle with it. The study provides an important contribution to the general understanding of brain functions.

As a next step, researchers plan to conduct age studies. In general, older people react more slowly than young people. So far, however, it is not known if this is a strategic process, for example, older people reacting more cautiously based on experience, or whether the longer reaction time is additionally due to brain structural changes,

(Max Planck Society, 15.09.2010 - NPO)