Pitt-led study maps the making of a decision in the human brain

October 30, 2007

PITTSBURGH--The brain, the human supercomputer, might work more like an assembly line when recognizing objects, with a hierarchy of brain regions separately absorbing and processing information before a person realizes what they are seeing, according to new research conducted at the University of Pittsburgh and published in the Oct. 31 edition of the Journal of Neuroscience.

Led by Mark Wheeler, a psychology professor in Pitt's School of Arts and Sciences, and conducted at Pitt's Learning Research and Development Center, the research is a step toward mapping the human decision-making process. This study used an innovative technique and analysis to show that human decision-making is a collaboration of brain regions performing individual functions. Future work based on these findings could lead to a better understanding of how decisions--good and bad--are made and the considerations people put into them.

The study is the first in humans to separate the areas of the brain active in the time leading up to a decision--which Wheeler terms evaluation areas--from the areas associated with communication and thinking that are traditionally related to decision-making, Wheeler said. It then lays out a hierarchy for the evaluation stage.

Wheeler and his colleagues used functional magnetic resonance imaging (fMRI) to track brain activity as study participants tried to recognize images gradually revealed to them. The pictures were blacked out then gradually revealed until the person viewing them recognized the image. As expected, activity increased in the brain's vision-processing centers as the picture was revealed and the brain absorbed the information.

The surprise came when activity also increased steadily in the brain's areas for object processing, reasoning, and memory. This suggests that these regions evaluated the images in the context of memories and past experiences as new information became available. Meanwhile, the brain regions already known to be active when a person makes a decision showed little change in activity until the person identified the picture. The flourish suggests that these regions handled the final recognition once the information was gathered.

These findings are consistent with previous research on monkeys that has shown the brain areas that are active when a decision is made, Wheeler said; however, this project, aside from pertaining to humans, also is the first to map the decision-making and evidence-gathering process prior to the actual "eureka" moment, he said.

"We're the first to show in humans the dynamic evolution of decision-dependent activity that we believe reflects evidence gathering," Wheeler said. "Our results relate particular parts of the brain to the evidence-gathering process, when your brain is taking in information to find out what the possibilities are. These evaluation areas process the information until that salient moment that the object a person is trying to recognize becomes obvious."

Not yet obvious is where the final decision actually forms, Wheeler said. Further research is needed to determine the point between the information-processing regions and the areas active at the moment of recognition, when a person comes to a conclusion.
-end-
Wheeler worked with Pitt graduate student Elisabeth Ploran and graduate student Steve Nelson from Washington University in St. Louis. Also part of the research team were Katerina Velanova of Pitt's Department of Psychiatry in the School of Medicine; Steven Petersen, a cognitive neuroscience professor at Washington University in St. Louis; and Psychology Professor David Donaldson of Stirling University in the United Kingdom.

Wheeler also is affiliated with Pitt's Center for Neuroscience and the Center for the Neural Basis of Cognition, a collaboration of Pitt and Carnegie Mellon University.

For more information on this research, visit the Journal of Neuroscience Web site at www.jneurosci.org.

University of Pittsburgh

Related Brain Articles from Brightsurf:

Glioblastoma nanomedicine crosses into brain in mice, eradicates recurring brain cancer
A new synthetic protein nanoparticle capable of slipping past the nearly impermeable blood-brain barrier in mice could deliver cancer-killing drugs directly to malignant brain tumors, new research from the University of Michigan shows.

Children with asymptomatic brain bleeds as newborns show normal brain development at age 2
A study by UNC researchers finds that neurodevelopmental scores and gray matter volumes at age two years did not differ between children who had MRI-confirmed asymptomatic subdural hemorrhages when they were neonates, compared to children with no history of subdural hemorrhage.

New model of human brain 'conversations' could inform research on brain disease, cognition
A team of Indiana University neuroscientists has built a new model of human brain networks that sheds light on how the brain functions.

Human brain size gene triggers bigger brain in monkeys
Dresden and Japanese researchers show that a human-specific gene causes a larger neocortex in the common marmoset, a non-human primate.

Unique insight into development of the human brain: Model of the early embryonic brain
Stem cell researchers from the University of Copenhagen have designed a model of an early embryonic brain.

An optical brain-to-brain interface supports information exchange for locomotion control
Chinese researchers established an optical BtBI that supports rapid information transmission for precise locomotion control, thus providing a proof-of-principle demonstration of fast BtBI for real-time behavioral control.

Transplanting human nerve cells into a mouse brain reveals how they wire into brain circuits
A team of researchers led by Pierre Vanderhaeghen and Vincent Bonin (VIB-KU Leuven, Université libre de Bruxelles and NERF) showed how human nerve cells can develop at their own pace, and form highly precise connections with the surrounding mouse brain cells.

Brain scans reveal how the human brain compensates when one hemisphere is removed
Researchers studying six adults who had one of their brain hemispheres removed during childhood to reduce epileptic seizures found that the remaining half of the brain formed unusually strong connections between different functional brain networks, which potentially help the body to function as if the brain were intact.

Alcohol byproduct contributes to brain chemistry changes in specific brain regions
Study of mouse models provides clear implications for new targets to treat alcohol use disorder and fetal alcohol syndrome.

Scientists predict the areas of the brain to stimulate transitions between different brain states
Using a computer model of the brain, Gustavo Deco, director of the Center for Brain and Cognition, and Josephine Cruzat, a member of his team, together with a group of international collaborators, have developed an innovative method published in Proceedings of the National Academy of Sciences on Sept.

Read More: Brain News and Brain Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.