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General interest items edited by Janice Flahiff

[News article]What makes peaceful neighbours become mass murderers : Nature News & Comment

What makes peaceful neighbours become mass murderers : Nature News & Comment.

From the 11 May 2015 news item

It’s time to ask uncomfortable questions about the brain mechanisms that allow ‘ordinary’ people to turn violent, says Itzhak Fried.

What happens in the brains of people who go from being peaceable neighbours to slaughtering each other on a mass scale? Back in 1997, neurosurgeon Itzhak Fried at the University of California, Los Angeles, conscious of the recent massacres in Bosnia and Rwanda, described this switch in behaviour in terms of a medical syndrome, which he called ‘Syndrome E’ 2. Nearly 20 years later, Fried brought sociologists, historians, psychologists and neuroscientists together at the Institute of Advanced Studies in Paris to discuss the question anew. At the conference, called ‘The brains that pull the triggers‘, he talked to Nature about the need to consider this type of mass murder in scientific as well as sociological terms, and about the challenge of establishing interdisciplinary dialogue in this sensitive area.

What are the main features of the syndrome?

There was a myth that the primitive brain is held in check by our more-recently evolved prefrontal cortex, which is involved in complex analysis, and that the primitive, subcortical part takes over when we carry out brutal crimes such as repetitive murder. But I saw it the other way around. The signs and symptoms that I gathered in my research indicated that the prefrontal cortex, not the primitive brain, was responsible, because it was no longer heeding the normal controls from subcortical areas. I called it ‘cognitive fracture’ — the normal gut aversions to harming others, the emotional abhorrence of such acts, were disconnected from a hyper-aroused prefrontal cortex. I also proposed a neural circuitry in the brain that could perhaps account for this. In brief, specific parts of the prefrontal cortex become hyperactive and dampen the activity of the amygdala, which regulates emotion.

If mass murder happens because of activity in the brain, what does this say about personal responsibility?

Perpetrators of repeated killings have the capacity to reason and to solve problems — such as how best practically to kill lots of people rapidly. Proposing the existence of a syndrome does not absolve them of responsibility.

May 19, 2015 Posted by | Medical and Health Research News | , , , , | Leave a comment

Human Brain Is Divided On Fear and Panic: Different Areas of Brain Responsible for External, Internal Threats

From the 4 February 2013 article at Science Daily

Feb. 4, 2013 — When doctors at the University of Iowa prepared a patient to inhale a panic-inducing dose of carbon dioxide, she was fearless. But within seconds of breathing in the mixture, she cried for help, overwhelmed by the sensation that she was suffocating.

The patient, a woman in her 40s known as SM, has an extremely rare condition called Urbach-Wiethe disease that has caused extensive damage to the amygdala, an almond-shaped area in the brain long known for its role in fear. She had not felt terror since getting the disease when she was an adolescent.

In a paper published online Feb. 3 in the journal Nature Neuroscience, the UI team provides proof that the amygdala is not the only gatekeeper of fear in the human mind. Other regions — such as the brainstem, diencephalon, or insular cortex — could sense the body’s most primal inner signals of danger when basic survival is threatened.

“This research says panic, or intense fear, is induced somewhere outside of the amygdala,” says John Wemmie, associate professor of psychiatry at the UI and senior author on the paper. “This could be a fundamental part of explaining why people have panic attacks.

nterestingly, the amygdala-damaged patients had no fear leading up to the test, unlike the healthy participants, many who began sweating and whose heart rates rose just before inhaling the carbon dioxide. That, of course, was consistent with the notion that the amygdala detects danger in the external environment and physiologically prepares the organism to confront the threat.

“Information from the outside world gets filtered through the amygdala in order to generate fear,” Feinstein says. “On the other hand, signs of danger arising from inside the body can provoke a very primal form of fear, even in the absence of a functioning amygdala.”

 

Read the entire article here

 

February 8, 2013 Posted by | Psychiatry | , , | 1 Comment

Structure deep within the brain may contribute to a rich, varied social life

Structure deep within the brain may contribute to a rich, varied social life

From a December 26, 2010 Eureka news alert

Scientists have discovered that the amygdala, a small almond shaped structure deep within the temporal lobe, is important to a rich and varied social life among humans. The finding was published this week in a new study in Nature Neuroscience and is similar to previous findings in other primate species, which compared the size and complexity of social groups across those species.

“We know that primates who live in larger social groups have a larger amygdala, even when controlling for overall brain size and body size,” says Lisa Feldman Barrett, PhD, of the Massachusetts General Hospital (MGH) Psychiatric Neuroimaging Research Program and a Distinguished Professor of Psychology at Northeastern University, who led the study. “We considered a single primate species, humans, and found that the amygdala volume positively correlated with the size and complexity of social networks in adult humans.”…

“This link between amygdala size and social network size and complexity was observed for both older and younger individuals and for both men and women,” says Bradford C. Dickerson, MD, of the MGH Department of Neurology and the Martinos Center for Biomedical Research. “This link was specific to the amygdala, because social network size and complexity were not associated with the size of other brain structures.” Dickerson is an associate professor of Neurology at Harvard Medical School, and co-led the study with Dr. Barrett….

…A member of the the Martinos Center at MGH, Barrett also notes that the results of the study were consistent with the “social brain hypothesis,” which suggests that the human amygdala might have evolved partially to deal with an increasingly complex social life. “Further research is in progress to try to understand more about how the amygdala and other brain regions are involved in social behavior in humans,” she says. “We and other researchers are also trying to understand how abnormalities in these brain regions may impair social behavior in neurologic and psychiatric disorders.”

 

December 27, 2010 Posted by | Medical and Health Research News | , , | Leave a comment

   

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