Distractions turn on different parts of our brains and do so more quickly than the daily grind of paying attention

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Separate regions are responsible for the different ways our brain focuses on the world around us, according to the study by MIT researchers, and our brain waves even pulsate at different frequencies depending on the type of outside stimulus.

"Neural activity goes up and down in a regular periodic way, with everything vibrating together," said study co-leader and neuroscientist Earl K. Miller. "It is faster for automatic stimulus and slower for things we choose to pay attention to."

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Scientists have always recognized two different ways that the brain processes information coming from the outside world. Willful focus (as occurs when you gaze at a piece of art) produces what are called "top-down" signals, while automatic focus (like when a wailing siren snaps you to attention) produces "bottom-up" signals. . .

Studying monkeys assigned to different tasks, Miller and co-author Timothy J. Buschman found that when a picture or object "popped out" at the creature, the parietal cortex jumped into action. When the monkeys were merely searching for the object, however, it was activity in the prefrontal cortex controlling the brain. This finding is the first to support this difference with concrete evidence. . .

"Anything that stands out as different from everything else—like a red apple in the middle of a green field—tends to grab your attention. . ." , activating the parietal cortex.


The prefrontal cortex is the seat of memory, language and abstract reasoning. For those with lower measured intelligence, the prefrontal cortex grew thicker with neuron-rich gray matter more quickly and reached a peak thickness at age 8. For the smartest kids, the cortex was thinner early on and didn't reach peak thickness until age 11.

The parietal cortex is the region of the brain that encodes the category or meaning of visual information.

The ability to take a piece of information through our senses, assign meaning to it and categorize it helps people make sense of the world around them and behave accordingly. Because of this, when a chair is seen by the eyes, it's deemed appropriate for sitting on.

"You're not born knowing about categories or things like chairs or tables or telephones," said lead author David Freedman, a postdoctoral research fellow in neurobiology at Harvard Medical School. "Instead those develop through learning."

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He and colleagues trained a group of monkeys to play a computer game in which they recognized dozens of visual patterns in one of two categories.

"Once they were trained, we monitored the activity of individual neurons while they were playing. . ."

Activity in the parietal cortex, the area around the middle of the brain right around the top of the head, was completely reorganized as a result of training. The parietal neurons mirrored the monkeys' decisions about which of the two categories each visual pattern belonged to.

Learning and experience also changed how the parietal cortex represented categories. . .
Over the course of few weeks, the monkeys were retrained to group the same visual patterns into two new categories. Parietal cortex activity was completely reorganized as a result of this retraining and encoded the visual patterns according to the newly learned categories. . .

"The activity didn't just encode what those visual patterns looked like," Freedman said. "Instead, the activity encoded what those patterns actually meant or what category those patterns belonged to."


(It occurs to me that if the parietal cortex doesn't have sufficient blood flow it won't work as efficiently and will keep yammering away until it gets an off signal.)