The Situationist

Posts Tagged ‘fMRI’

The Neuro-Situation of Moral and Economic Decisions

Posted by The Situationist Staff on March 21, 2010

From ThirteenWNET:

To Steven Quartz & Colin Camerer the brain is a huge number-cruncher, assigning a numeric value to everything from a loaf of bread to our most deeply held moral “values.” In that sense, moral decisions are also economic ones. Using a brain scanner (fMRI), they want to catch the brain in the act—to see what it’s doing at exactly the moment a tough moral decision gets made. Their research is pioneering a new branch of neuroscience — neuroeconomics.

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To review a sample of related Situationist posts, see “The Legal Brain,” Read My Brain – From Science Friday,” “The Situation of Neuroeconomics and Situationist Economics,” and “The Interior Situational Reaction to Inequality.”

Posted in Behavioral Economics, Distribution, Emotions, Neuroeconomics, Neuroscience, Video | Tagged: , , , | 2 Comments »

Nancy Kanwisher on the Situation of our Brain

Posted by The Situationist Staff on August 25, 2009

BrainFor Observer, publisehd by the Association for Psychological Science, Ann Conkle wrote a nice summary of Nancy Kanwisher‘s fascinating keynote address at this years APS Annual Convention in San Francisco.  Here are some excerpts of Conkle’s article, titled “Sharpening the Focus on Brain Function.”

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Is your brain like a Swiss Army knife? . . . Is it jam-packed with specialized tools that are unfolded only when a specific situation arises? Or is it more all-purpose, with a few parts that tackle many different situations? Convention Keynoter and APS Fellow Nancy Kanwisher (Massachusetts Institute of Technology) is attempting to find out.

Following centuries of debate about specialized brain regions — from the phrenologists to Broca — the development of fMRI technology has ushered in a new era of studying brain regions. By monitoring the blood flow necessary to support neural activity, fMRI has allowed researchers to track which regions of the brain are involved in processing specific stimuli. With this new weapon in her arsenal, Kanwisher performed a now-classic study published in 1997. In it, participants sat in an fMRI scanner while looking a series of faces and objects. She and her colleagues identified an area in the fusiform gyrus on the bottom surface of the temporal lobe that responded more strongly when the participants viewed faces than when they viewed objects. Dubbed the fusiform face area, this region seemed like it could be specialized for processing faces.

But the researchers could not yet be sure. What if the area responded to everything animate, or everything round? A decade of more detailed research confirmed their original hypothesis — the fusiform face area lived up to its name. At the same time, Kanwisher’s lab discovered two other specialized areas: the parahippocampal place area, which specializes in processing places, and the extrastriate body area, which specializes in processing images of the body.

These answers only lead to more questions. These areas are involved in processing certain categories, but do they merely process perceptual input or actually reflect conscious experience? What are the roles of genes and experience in wiring up these areas? And finally, how much of the brain is like this? Is our entire cortex broken up into small pieces, each with their own special domain? Kanwisher and her colleagues are tackling these questions head on.

Do these areas only engage in their respective categorical processing or do they perform other functions as well? For example, take the fusiform face area. It is most active when viewing faces, but it also shows lesser activity when the participant is looking at other visual stimuli, like objects. Something in the pattern of this lower activity could be crucial in processing input other than faces. Evidence against this idea comes from research on patients with neurological trauma, who sometimes lose face perception abilities without losing object perception. But, the low chance of finding subjects with a lesion in just the right spot make this research limited. Other researchers have turned to transcranial magnetic stimulation (TMS), a method that uses magnetic fields to transiently disrupt neural activity. The fusiform face area is too deep in the brain to be affected by TMS, but the extrastriate body area is closer to the scalp and susceptible to the TMS disruption. When the neural activity in this region is disturbed, participants are impaired in the ability to recognize bodies but have no difficulty recognizing faces or other objects. Although these specialized areas may collect information about other types of stimuli, it seems that they are only necessary for processing information of their specific type.

Are the functionally specific regions merely perceptual processers or do they reflect our conscious experience? To illustrate the difference between perception and experience, Kanwisher instructed the audience to pick up the 3-D glasses left on the seats. But, before we could put them on, she showed us two images, a red-tinted image of a face and a green-tinted image of a house. Then she superimposed the house on the face creating a red/green face/house jumble. But, when looking at this jumble through glasses with one red-tinted and one green-tinted lens, so that the house image goes to one eye and the face image to the other, you don’t experience a jumble — you experience a red face that fades to a green house and back and forth as your brain attempts to make sense of this new situation. Even though your experience of what you are seeing is changing, the image beamed to your retina is constant the whole time. Work from Kanwisher’s lab showed that in this situation, activity in the fusiform face area corresponds with one’s experience, not with the actual perceptual input.

Further, not only does the activity in specialized areas correspond with what we consciously see, it also corresponds with what we imagine. Kanwisher has put people in the fMRI machine and asked them to imagine familiar faces and places. The same areas are active when participants are imagining faces and places as when they are actually looking at faces and places. It’s not just what you are physically seeing, but what you are consciously aware of that is processed by this area.

So, where do these specialized areas come from? What role do genes and experience play in their construction?

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For answers to those questions and the rest of Conkle’s summary of Kanwisher’s talk, click here.

To watch a video of Kanwisher’s Keynote presentation, click on the video below.

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For a sample of related Situationist posts, “Smart People Thinking about People Thinking about People Thinking” and ““The Grand Illusion” — Believing We See the Situation.”  To review a collection of Situationist posts on neuroscience, click here.

Posted in Classic Experiments, Neuroscience, Video | Tagged: , , , | 2 Comments »

Learning to Influence Our Interior Situation

Posted by The Situationist Staff on July 16, 2008

From TED: Neuroscientist and inventor Christopher deCharms demonstrates a new way to use fMRI to show brain activity — thoughts, emotions, pain — while it is happening. In other words, you can actually see how you feel.

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Posted in Neuroscience, Video | Tagged: , , , , , | Leave a Comment »

Mapping the Social Brain

Posted by The Situationist Staff on May 16, 2008

What goes through your head when you hear that you have a good reputation or find out that your social status is slipping? Researchers are starting to find out. By examining brain activity through functional magnetic resonance imaging (fMRI), two groups of researchers report how our brains respond to information about reputation and social status in the journal Neuron this week.

Caroline Zink, a neuroscientist from the National Institute of Mental Health, and colleagues developed a simple game in which participants played for money. The participants were competing against themselves only. The researchers told the players, however, that other people happened to be playing the same game simultaneously and then gave the participants information about how well they were doing compared to these other players.

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When participants in Zink’s study viewed a superior player, regions of the brain associated with social-emotional processing–like the amygdala–were activated. “If you think about it, it makes sense that you wouldn’t have the same kind of emotional response if it was a computer,” Zink says.

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Researchers also recently mapped the neural response to reputation. “Although we all intuitively know that a good reputation makes us feel good, the idea that good reputation is a reward has long been just an assumption in social sciences, and there has been no scientific proof,” says Norihiro Sadato, a researcher at the National Institute for Physiological Sciences in Aichi, Japan and author of another study in Neuron this week.

Sadato and colleagues report that when people are told that they have a good reputation, regions of the brain associated with the reward are activated. A good reputation prompts a similar neural response to a monetary reward. “We found that these seemingly different kinds of rewards (good reputation vs. money) are biologically coded by the same neural structure, the striatum,” Sadato writes in an email

Posted in Emotions, Neuroscience, Uncategorized | Tagged: , , , , , , | Leave a Comment »

 
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