What’s the News: One of memory’s big jobs is to keep straight what actually happened versus what we imagined: whether we said something out loud or to ourselves, whether we locked the door behind us or just thought about locking the door. That ability, a new study found, is linked to the presence of a small fold in the front of the brain, which some people have and others don’t—a finding that could help researchers better understand not only healthy memory, but disorders like schizophrenia in which the line between the real and the imagined is blurred.
Scans of a brain with a distinctive paracingulate sulcus (left, marked by arrow) and without one (right)
Children of older mothers, scientists have long known, are at higher risk for certain genetic disorders such as Down syndrome. But the father’s age is matters, too. As a father’s age increases, research shows, so does his child’s risk of mental illness, schizophrenia and autism in particular. In Scientific American, Nicole Grey explores the link between a father’s age and his child’s health, as well as the tricky questions about what mechanisms are behind the that link: genes, epigenetic changes, environment, or some combination of the three.
What’s the News: Researchers have simulated the symptoms of schizophrenia using a language-learning computer program, in a recent study published in Biological Psychiatry. The computer started showing schizophrenia-like symptoms when it was set to learn too much and forget too little. This study lends support to the hyperlearning hypothesis, that the brains of people with schizophrenia have trouble forgetting or filtering out irrelevant information.
What’s the Context:
What’s the News: Researchers have grown neurons from the cells of people with schizophrenia, in a study published online yesterday in Nature, the first time a complex mental illness has been modeled with living cells in a lab. This approach provides a new way to probe the little-understood biological processes underlying the disease and to test potential drug treatments. In preliminary experiments, the researchers found that the neurons weren’t as interconnected as healthy neurons are, and that individual patients’ neurons differ in their reaction to various drugs used to treat schizophrenia.
A neuroscientist whose car was firebombed by violent animal rights activists has decided to fight back, at least in the court of public opinion. The UCLA professor, David Jentsch, has formed a group called UCLA Pro-Test, and is organizing a rally in support of animal testing. “People always say: ‘Don’t respond. If you respond, that will give [the attackers] credibility,'” Jentsch, 37, said in a recent interview in his UCLA office. “But being silent wasn’t making us feel safer. And it’s a moot point if they are coming to burn your car anyway, whether you give them credibility or not” [Los Angeles Times].
UCLA Pro-Test, named after a similar group in the United Kingdom, wants to show its support for animal research that is conducted in a humane and regulated way. Jentsch studies schizophrenia and drug addiction, and works on both rodents and vervet monkeys.
The Animal Liberation Brigade took credit for bombing Jentsch’s Volvo as it sat in his driveway in the early morning hours of March 7. The activist group wrote in an Internet posting: “The things you and others like you do to feeling, sentient monkeys is so cruel and disgusting we can’t believe anyone would be able to live with themselves…. David, here’s a message just for you, we will come for you when you least expect it and do a lot more damage than to your property” [Los Angeles Times].
Two large, international studies have independently found three genetic mutations that are linked to a greatly increased risk of schizophrenia, but say the rare mutations only account for a small percentage of schizophrenia cases. The identification of the three mutations is being hailed as a breakthrough, as no genetic factors had been definitively linked to the disease before. But in a finding of even greater importance, the studies suggest that there’s no easy answer to the question of what causes the devastating mental illness. Instead of a common genetic problem, schizophrenia may be triggered by many rare mutations that cause subtly different variants of the disease.
“What is beginning to emerge is that a lot of the risk of brain diseases is conferred by rare [genetic] deletions,” [study author Kari] Stefansson said…. The new focus on rare mutations suggests that natural selection is highly efficient at removing schizophrenia-causing genes from the population. Despite selection against the disease, according to this new idea, schizophrenia continues to appear because it is driven by a spate of new mutations that occur all the time in the population. [The New York Times].
Researchers have made a map of the human brain that shows a dense network of connections at the top of the cerebral cortex, suggesting that electrical signals travel through this hub on their way to more specialized regions. “This is just about the coolest paper I’ve seen in a long time, and forward-looking in terms of where the science is going,” said Dr. Marcus E. Raichle, a professor of neurology and radiology… who was not involved in the research. He added, “They’ve found in the brain what looks like a hub map of the airline system for the United States” [The New York Times].
An international team of researchers used a technique called diffusion spectrum imaging to map the connections between different parts of the brain. The technique traces the path of water moving along axons, long fibers that extend from a neuron’s main body and carry electrical signals [Science News]. They found the most connections at the top of the cortex along the crack that separates the brain’s two hemispheres. According to researchers, that area is not only a relay station, it’s also the area that’s most active when the brain is in “default mode,” the activation state present when the brain is not engaged in any specific cognitive task [The Scientist].