Practice really can change the brain.

Researchers at Georgetown University Medical Center say extensive training can physically reorganise brain activity, shifting a learned task away from the prefrontal cortex and into specialised circuits. They say that change can free up the brain’s main “thinking” centre to handle something else at the same time.

“We have another stepping stone in our understanding of how the brain learns,” said senior author Maximilian Riesenhuber, PhD, a professor of neuroscience at Georgetown University School of Medicine and co-director of the Center for Neuroengineering.

“The encouraging part is that you really can learn to multitask. There is actually a way to remodel your brain architecture and use other parts of your brain.”

The study looked at what happens after a skill has been practised so much that it becomes almost effortless. Riesenhuber pointed to driving as a familiar example.

“The question is: how does your brain do that?” Riesenhuber said.

To test it, researchers asked volunteers to sort morphed images of cars into two categories by spotting subtle visual differences. Participants completed more than 30,000 sorting trials over 5 to 10 weeks using a smartphone app designed as a game.

The team used fMRI and EEG scans before training started and again after it ended.

Early in learning, the task mainly activated the prefrontal cortex, the area linked to planning, reasoning and conscious decision-making. After weeks of practice, brain activity had shifted, and the same task was handled mainly by the temporal cortex, which is involved in memory and recognising complex objects.

“Previous studies have shown that parts of the temporal cortex can be activated by particular object categories in experienced observers, birds, cars, even Pokémon, but a limitation of all of those studies is that they only looked after people became experts. The strength of this study is that it is longitudinal; we measure before and after training, so we can see that extensive training essentially put a category-selective area in the temporal lobe that was not there before,” said first author Patrick Cox, PhD, who began the study as a graduate student in Riesenhuber’s lab and is now an assistant professor of psychology at Lehigh University.

“This has implications for critical real-world scenarios, like when a radiologist can accurately classify masses on an X-ray as benign or malignant fairly automatically, often without extensive deliberation, thanks to years of training,” Cox said.

The researchers found information from the newly developed car-selective area in the temporal cortex could bypass the prefrontal cortex and travel directly to brain regions responsible for producing responses.

“Experience remodels the brain to bypass that frontal bottleneck. The prefrontal cortex then stays free for whatever else you want to do, increasing your capacity,” Riesenhuber said.

The team also found that the more the car-sorting task was offloaded from the prefrontal cortex, the better participants performed a second task at the same time.

“What we show is that the circuitry actually changes so the brain can do two things at once,” Riesenhuber said. “This really is true multitasking.”

The findings may also help explain compulsive behaviours, the researchers said, because well-learned behaviours move into brain circuits that depend less on conscious control.

“The first step to unlearning something is understanding where it is actually happening in the brain,” Riesenhuber said.

“This shows why strategies like telling someone to think of something else don’t really help, because they don’t really have the behavior under conscious control.”

The team said the findings may also help explain why humans keep building new abilities throughout life while current AI systems still struggle to learn continuously without disrupting earlier knowledge.

The researchers now plan to study what signals move learning from one brain region to another and which kinds of tasks can eventually be done in parallel.

“Another really interesting question is what kinds of tasks can be learned well enough to do in parallel,” Cox said.

“We can walk and chew gum at the same time, but looking at our phones to text while driving will never be safe, because we take our eyes away from the road. It comes down to being able to train fully separate neural circuits for two tasks to become compatible.”

The study, “Extensive Experience Remodels Neural Task Circuitry to Escape the Frontal Bottleneck and Increase Automaticity of Categorization,” was published June 4 in the Journal of Cognitive Neuroscience.

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