Network structure and dynamics of the mental workspace

Paper authored by Peter Tse and Alex Schiegel and published in the PNAS.

We do not know how the human brain mediates complex and creative behaviors such as artistic, scientific, and mathematical thought. Scholars theorize that these abilities require conscious experience as realized in a widespread neural network, or “mental workspace,” that represents and manipulates images, symbols, and other mental constructs across a variety of domains. Evidence for such a complex, interconnected network has been difficult to produce with current techniques that mainly study brain activity in isolation and are insensitive to distributed informational processes. The present work takes advantage of emerging techniques in network and information analysis to provide empirical support for such a widespread and interconnected information processing network in the brain that supports the manipulation of visual imagery.

Travis Todd Receives New Investigator Award

Dr. Travis Todd, a postdoctoral fellow in Professor David Bucci’s laboratory, has received the 2013 New Investigator Award from the American Psychological Association (Division of Experimental Psychology).  The New Investigator award is presented annually to an early-career author whose article was deemed the very best of the year by the APA journal editors or editorial boards.  Dr. Todd received the award for the article: 

Todd, T. P. (2013). Mechanisms of renewal after the extinction of instrumental behavior. Journal of Experimental Psychology: Animal Behavior Processes, 39(3), 193-207.

Before coming to Dartmouth, Dr. Todd earned his PhD in Experimental Psychology from the University of Vermont in February, 2013, working with Professor Mark Bouton.

You Want Fries With That? Don't Go There.

New Dartmouth study of chronic dieters suggests brain disruptions weaken will power.

A new Dartmouth neuroimaging study suggests chronic dieters overeat when the regions of their brain that balance impulsive behavior and self-control become disrupted, decreasing their capacity to resist temptation.

The findings, which appear in the journal Psychological Science, indicate that chronic dieters will have more success if they avoid situations that challenge their self-control. A PDF of the study is attached.

The results shed new light on brain mechanisms involved in obesity, substance abuse and other impulsive health problems. Going forward, the Dartmouth researchers are looking into whether self-control can be strengthened over time – much like muscles are strengthened through exercise and rest -- by routinely resisting minor temptations.

How Imagination Works (Popular Science)

Popular Science features new Dartmouth research that focuses on what the brain’s “mental workplace” looks like when people manipulate images in their mind.

“Our lab is very interested in the kind of flexible cognitive behaviors that humans have,” Alex Schlegel, a graduate student in the Department of Psychological and Brain Sciences, and lead author of the study, tells Popular Science. “We can learn new things, we can think of new concepts, seeing things from different perspectives—a lot of this has to do with a very rich mental space, kind of a mental playground.”

Participants in the study were asked to look at pictures of abstract shapes, explainsPopular Science. While undergoing an fMRI scan, they were asked to recall or manipulate the images in their mind. “We saw differences in activity all over the brain when we compared to control conditions,” Schlegel tells the magazine. “Rather than being a single area responsible for imagining or manipulating, it seems like lots of areas have to work in concert.”

Read the full story, published 9/16/13 by Popular Science.

Alda’s ‘Brains on Trial’ Tapped Dartmouth’s Expertise

Bill Platt

Neuroscience plays a starring role in a two-part series Brains on Trial With Alan Alda, airing on PBS Wednesday, September 11, and Wednesday, September 18, from 10 to 11 p.m., a project that Dartmouth Professor Thalia Wheatley, an expert in brain science and social intelligence, worked on as a consultant.

Brains on Trial centers on the trial of a fictional crime: a robbery staged in a convenience store. A teenager stands accused of the attempted murder of the store clerk’s wife, who was shot during the crime. While the crime is fictional, the trial is conducted before a real federal judge and argued by real practicing attorneys.

Familiar Faces (ScienceNews)

In a story about “super recognizers”—people who have an exceptional ability to remember faces—ScienceNews turns for comment to Dartmouth’s Bradley Duchaine.

Duchaine, an associate professor of psychological and brain sciences, and colleagues in England are studying super recognizers to understand how some people are able to recognize nearly everyone they’ve ever seen, the magazine writes. Knowledge gained from such studies may aid in police work and other fields that rely on identifying people by how they look, notes the magazine.

“By identifying strategies used by super recognizers, we may find ways to train others who have problems with face recognition, or help people who are in the normal range but have professional demands in which superior face recognition would be beneficial,” Duchaine tells ScienceNews.

Read the full story, published 8/23/13 by ScienceNews.

Scientists Identify an Off Switch for Bad Habits

What if the brain had a light switch that could be flipped to turn off a bad habit?

Research by Assistant Professor Kyle Smith, who joined the faculty of Dartmouth’s Department of Psychological and Brain Sciences last month, has found just that in lab rats. Smith and others have identified brain cells involved in habit formation and inhibition. Researchers introduced DNA for photosensitive molecules into the brain’s cortex to make specific neurons respond to light from a fiber optic implant. Then, by flashing a light on these key cells, researchers managed to abruptly halt habits and inhibit the formation of new habitual behaviors. 

Smith and his colleagues trained rats to run a maze for a reward. They then overtrained the animals so they ran the pattern even after the behavior brought negative results—in this case, food that tasted bad. So the rats continued the habit, in a sense, against their better judgment. It is not unlike a person continuing to bite his fingernails even though he wants to stop, Smith says.

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