Posts tagged brain areas

Posts tagged brain areas
Some people live their lives by the motto “no risk - no fun!” and avoid hardly any risks. Others are clearly more cautious and focus primarily on safety when investing and for other business activities. Scientists from the University of Bonn in cooperation with colleagues from the University of Zurich studied the attitudes towards risk in a group of 56 subjects. They found that in people who preferred safety, certain regions of the brain show a higher level of activation when they are confronted with quite unforeseeable situations. In addition, they do not distinguish as clearly as risk takers whether a situation is more or less risky than expected. The results have just been published in the renowned “Journal of Neuroscience.”
"We were especially interested in the link between risk preferences and the brain regions processing this information," says Prof. Dr. Bernd Weber from the Center for Economics and Neuroscience (CENs) at the University of Bonn. First, the researchers tested a total of 56 subjects for their willingness to take risks. "In an economic game, the test subjects had a choice between a secured payout and a lottery," reports Sarah Rudorf from CENs, the study’s principal author. Those who showed a strong preference for the lottery in this test were categorized as risk takers. Others preferred the secured payout even if the lottery’s odds of winning were clearly better. They were put in the risk-averse group.
In risk-averse individuals, certain regions of the brain are activated more strongly
Then the test subjects played a card game in a brain scanner to study their risk perception. Cards carrying numbers from one to ten were shown on the video glasses in front of their eyes. Each time, two cards were randomly drawn. Before the subjects were shown the cards, they were asked to place bets on whether the second card would have a higher or a lower number than the first one. “The statistical probability for either case to occur is always the same: fifty-fifty,” says Prof. Weber. “This is important so that all subjects, whether they are risk takers or not, experience risky situations inside the scanner.” They were not able to assess their probability of winning their bet until they saw the first card. Here, the researchers found that in the subjects who tended to avoid risks, two specific regions of the brain were activated more strongly than in those who were willing to take risks. These areas are the ventral striatum and the insular cortex. The ventral striatum reacts both to the probability of winning, as well as to how well an individual can predict the outcome of the bet. The insular cortex is particularly sensitive to the risk a situation carries, and for whether it is higher or lower than anticipated.
Risk seekers adjust their strategy after lucky streaks
Sarah Rudorf summarized the results, “Individuals in whom these regions of the brain are activated at a higher level seem to perceive risks more clearly and assess them as more negative than those who are willing to take risks.” Risk-averse individuals seem to overestimate the con¬sequences of risk, and they did not distinguish as clearly between situations that turned out to be more or less risky than expected. In contrast, the test subjects who tended to take greater risks also focused their behavior more towards the wins and losses, and more clearly changed their strategy after negative situations.
Study is first to show the neurobiological mechanisms
"This study is the first to show the neurobiological mechanisms of how individual risk preferences determine risk perception," says Prof. Weber. "This also has effects on behavior in the areas of finance and health."
In a next step, the researchers want to study the consequences these results have on economic decisions such as in the stock market. “This might even allow improving the advising process for investors with regard to their individual risk behavior,” says Prof. Weber. And he considers health another important area. Smokers know that what they do is very dangerous, and yet they smoke. “If we learned more about smokers’ attitudes towards risk, we might be able to provide information for developing better anti-smoking campaigns.”
(Source: www3.uni-bonn.de)
360 degree brain
This interactive feature gives visitors a chance to get a close-up of the brain’s structure. This brain was removed from a man’s skull shortly after his death and came from the Parkinson’s UK Brain Bank at Imperial College.
Zooming in on the human brain
A visually compelling tour of the human brain, from anatomy to cells to genes and back.
In everyday life we rarely consciously try to lip-read. However, in a noisy environment it is often very helpful to be able to see the mouth of the person you are speaking to. Researcher Helen Blank at the MPI in Leipzig explains why this is so: “When our brain is able to combine information from different sensory sources, for example during lip-reading, speech comprehension is improved.” In a recent study, the researchers of the Max Planck Research Group “Neural Mechanisms of Human Communication” investigated this phenomenon in more detail to uncover how visual and auditory brain areas work together during lip-reading.
In the experiment, brain activity was measured using functional magnetic resonance imaging (fMRI) while participants heard short sentences. The participants then watched a short silent video of a person speaking. Using a button press, participants indicated whether the sentence they had heard matched the mouth movements in the video. If the sentence did not match the video, a part of the brain network that combines visual and auditory information showed greater activity and there were increased connections between the auditory speech region and the STS.
“It is possible that advanced auditory information generates an expectation about the lip movements that will be seen”, says Blank. “Any contradiction between the prediction of what will be seen and what is actually observed generates an error signal in the STS.”
How strong the activation is depends on the lip-reading skill of participants: The strong-er the activation, the more correct responses were. “People that were the best lip-readers showed an especially strong error signal in the STS”, Blank explains. This effect seems to be specific to the content of speech - it did not occur when the subjects had to decide if the identity of the voice and face matched.
The results of this study are very important to basic research in this area. A better understanding of how the brain combines auditory and visual information during speech processing could also be applied in clinical settings. “People with hearing impairment are often strongly dependent on lip-reading”, says Blank. The researchers suggest that further studies could examine what happens in the brain after lip-reading training or during a combined use of sign language and lip-reading.