Researchers claim to have zeroed in on the part of the brain that allows mice to multitask. They think the same may be true for humans.
The researchers at NYU Langone Medical Center were studying a part of the brain already suspected to be the "switchboard" controlling an animal's attention. That region is called the thalamic reticular nucleus (TRN); thalamic means "front of the brain," reticular means "fibrous," and nucleus means "activity hub."
The TRN essentially tells the brain what to focus on and what to block out. Ever notice that you don't smell your aunt's kitty litter box after you've been in her house for an hour? Your TRN has told your brain it doesn't need to focus on that smell any more. Essentially, it has deemed it safe and therefore unworthy of your attention. (Thanks, TRN. That was gross.) Such was the theory, now strengthened by the recent research.
All mammals have a TRN, including mice and rats. So the researchers experimented with this region in mice's brains, to see how they could manipulate the animals' attention. To get there, they had to develop an elaborate trick.
First, they taught the mice that they could get a reward (a yummy milk drink) if they followed a flashing light. Once the animals had started looking for lights to guide them to their treat, they found the milk about 90 percent of the time. Then the researchers started attempting to distract them. They made loud noises (I like to imagine they were armpit toots) that would startle the mice, or at least divide their attention for a moment. In some cases, the sounds continued; in others, they stopped. But either way, the mice only found their milk 70 percent of the time after they heard the noise. They had been successfully distracted.
Then, the researchers took the most telling step: they gauged the activity in the TRN. And there it was: the neurons that control visual processing (finding the light and following it to the milk) were suppressed to make room for the neurons controlling audio processing (the armpit farts). Essentially, the brain was "multitasking," but at a huge price to the task at hand.
"Filtering out distracting or irrelevant information is a vital function," explained Dr. Michael Halassa, a neuroscientst, psychiatrist, and co-author of the study, in a press release. "People need to be able to focus on one thing and suppress other distractions to perform everyday functions such as driving, talking on the phone, and socializing."
And rats need to be able to focus on milk.
It seems as though damage to this region, or simply reduced size or efficacy of the TRN, could effectively ruin one's ability to control their attention. To test that theory, the researchers inactivated the TRN in the mice. Unsurprisingly, the mice were at a near-total loss at finding the milk.
The finding could lead to new discoveries in treating conditions where attention management is fraught with problems: ADHD, autism, sensory processing disorder, and schizophrenia among them.
It may be worth noting that a 2011 study, noted in Psychology Today, found that people who think they are the best at multitasking are actually the worst at it. You may think you have a great TRN, but you are actually running it ragged when you ask it to juggle all those sensory inputs. Best to take it one thing at a time.
The new study is published online in the journal Nature.
Photo: David Goehring | Flickr
