Researchers pinpoint epicenter of brain’s predictive ability
In recent years, sciÂenÂtists have disÂcovÂered the human brain works on preÂdicÂtions, conÂtrary to the preÂviÂously accepted theory that it reacts to the senÂsaÂtions it picks up from the outÂside world. Experts say humans’ reacÂtions are in fact the body adjusting to preÂdicÂtions the brain is making based on the state of our body the last time it was in a simÂilar situation.
Now, UniÂverÂsity DisÂtinÂguished ProÂfessor Lisa Feldman BarÂrett at NorthÂeastern has reported finding the epiÂcenter of those predictions.
In an article pubÂlished in Nature last week, BarÂrett conÂtends that limbic tissue, which also helps to create emoÂtions, is at the top of the brain’s preÂdicÂtion hierÂarchy. She co-authored the paper with W. Kyle SimÂmons, of the LauÂreate InstiÂtute for Brain Research in Tulsa, Oklahoma.
“The unique conÂtriÂbuÂtion of our paper is to show that limbic tissue, because of its strucÂture and the way the neuÂrons are orgaÂnized, is preÂdicting,†BarÂrett said. “It is directing the preÂdicÂtions to everyÂwhere else in the cortex, and that makes it very powerful.â€
For example, when a person is instructed to imagine a red apple in his or her mind’s eye, BarÂrett explained that limbic parts of the brain send preÂdicÂtions to visual neuÂrons and cause them to fire in difÂferent patÂterns so the person can “see†a red apple.
BarÂrett is a facÂulty member in the DepartÂment of PsyÂchology and is director of the InterÂdisÂciÂpliÂnary AffecÂtive SciÂence LabÂoÂraÂtory. A pioÂneer in the psyÂchology of emoÂtion and affecÂtive neuÂroÂscience, she has chalÂlenged the founÂdaÂtion of affecÂtive sciÂence by showing that people are the archiÂtects of their own emoÂtional experiences.
In the Nature paper, BarÂrett sumÂmaÂrized research on the celÂlular comÂpoÂsiÂtion of limbic tissue, which shows that limbic regions of the brain send but do not receive preÂdicÂtions. This means that limbic regions direct proÂcessing in the brain. They don’t react to stimÂuÂlaÂtion from the outÂside world. This is ironic, BarÂrett argues, because when sciÂenÂtists used to believe that limbic regions of the brain were the home of emoÂtion, they were seen as mainly reacÂtive to the world.
Common sense tells you that seeing is believing, but really the brain is built for things to work the other way around: you see (and hear and smell and taste) what you believe. And believing is largely based on feeling. In her paper, BarÂrett shows that your brain is not wired to be a reacÂtive organ. It’s wired to ask the quesÂtion: “The last time I was in a sitÂuÂaÂtion like this, what senÂsaÂtions did I encounter, and how did I act?†And the senÂsaÂtions that seem to matter most are the ones that are inside your own body, which are called “interoceptions.â€
“What your brain is trying to do is guess what the senÂsaÂtion means and what’s causing the senÂsaÂtions so it can figure out what to do about them,†BarÂrett said. “Your brain is trying to put together thoughts, feelÂings, and perÂcepÂtions so they arrive as needed, not a second afterwards.â€
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