Mindless distractions might not reduce anxiety as effectively as a brain teaser.

A brain-imaging study published last year by Nature Neuroscience suggests such brain-sharpening activities as crossword puzzles reduce anxiety by activating a region of the brain devoted to logic and concentration — the prefrontal cortex.

“This is being supported by burgeoning neuropsychologic data,” said Dr. Carl Aagesen, a psychiatrist at Medical Associates Clinic. “The prefrontal cortex is used for planning, making judgments and delaying impulses. This part of our brain is how we do self-talk to turn down input from the amygdala.”

The amygdala is the source of the brain’s “fight-or-flight reflex,” which alerts the body to protect itself in times of danger and is thought to contribute to feelings of anxiety.

Surveys indicate one in five adults experience above-average levels of anxiety annually and research has shown anxious people struggle to concentrate.

Sonia Bishop, a UC Berkeley psychologist and lead author of the brain imaging study, used functioning Magnetic Resonance Imaging to study 17 men and women, ranging in age from 19 to 48, at Cambridge University. They scored in standardized tests as having varying levels of anxiety, but were not on medication.

Their brains were scanned as they performed letter-searching tasks. When the letter search was demanding, brain scans showed all the study participants’ dorsolateral prefrontal cortexes, which control planning, organization and memory, to be fully engaged.

But when the letter search was easy, the prefrontal brain activity in high-anxiety participants plummeted as their attention wandered.

In contrast, low-anxiety participants easily activated the prefrontal brain to focus on the task at hand when presented with distractions. Aagesen describes the brain as functioning like a computer. “It cannot do two things simultaneously, but it can shift back and forth almost instantaneously,” he said.

Crossword puzzles, math games, mazes and other brain-teasing activities actively engage the prefrontal cortex — which can calm anxiety.

“The more you engage the dorsolateral prefrontal cortex actively, the more you are able to shut down input from the fear centers, because you can’t do two things at once,” Aagesen said.

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