Brain connectivity study reveals striking differences between men and women

Penn Medicine brain imaging study helps explain different cognitive strengths in men and women PHILADELPHIA—A new brain connectivity study from Penn Medicine published today in the Proceedings of National Academy of Sciences found striking differences in the neural wiring of men and women that's lending credence to some commonly-held beliefs about their behavior. In one of the largest studies looking at the "connectomes" of the sexes, Ragini Verma, PhD, an associate professor in the department of Radiology at the Perelman School of Medicine at the University of Pennsylvania, and colleagues found greater neural connectivity from front to back and within one hemisphere in males, suggesting their brains are structured to facilitate connectivity between perception and coordinated action. In contrast, in females, the wiring goes between the left and right hemispheres, suggesting that they facilitate communication between the analytical and intuition. "These maps show us a stark difference--and complementarity--in the architecture of the human brain that helps provide a potential neural basis as to why men excel at certain tasks, and women at others," said Verma. For instance, on average, men are more likely better at learning and performing a single task at hand, like cycling or navigating directions, whereas women have superior memory and social cognition skills, making them more equipped for multitasking and creating solutions that work for a group. They have a mentalistic approach, so to speak. Past studies have shown sex differences in the brain, but the neural wiring connecting regions across the whole brain that have been tied to such cognitive skills has never been fully shown in a large population. In the study, Verma and colleagues, including co-authors Ruben C. Gur, PhD, a professor of psychology in the department of Psychiatry, and Raquel E. Gur, MD, PhD, professor of Psychiatry, Neurology and Radiology, investigated the gender-specific differences in brain connectivity during the course of development in 949 individuals (521 females and 428 males) aged 8 to 22 years using diffusion tensor imaging (DTI). DTI is water-based imaging technique that can trace and highlight the fiber pathways connecting the different regions of the brain, laying the foundation for a structural connectome or network of the whole brain. This sample of youths was studied as part of the Philadelphia Neurodevelopmental Cohort, a National Institute of Mental Health-funded collaboration between the University of Pennsylvania Brain Behavior Laboratory and the Center for Applied Genomics at the Children's Hospital of Philadelphia. The brain is a roadmap of neural pathways linking many networks that help us process information and react accordingly, with behavior controlled by several of these sub-networks working in conjunction. In the study, the researchers found that females displayed greater connectivity in the supratentorial region, which contains the cerebrum, the largest part of the brain, between the left and right hemispheres. Males, on the other hand, displayed greater connectivity within each hemisphere. By contrast, the opposite prevailed in the cerebellum, the part of the brain that plays a major role in motor control, where males displayed greater inter-hemispheric connectivity and females displayed greater intra-hemispheric connectivity. These connections likely give men an efficient system for coordinated action, where the cerebellum, which involves perception, and the front of the brain, which involves action, are bridged together, according to the authors. The female connections likely facilitate integration of the analytic and sequential processing modes of the left hemisphere with the spatial, intuitive information processing modes of the right side. The authors observed only a few gender differences in the connectivity in children younger than 13 years, but the differences were more pronounced in adolescents aged 14 to 17 years and young adults older than 17. The findings were also consistent with a Penn behavior study, of which this imaging study was a subset of, that demonstrated pronounced sexual differences. Females outperformed males on attention, word and face memory, and social cognition tests. Males performed better on spatial processing and sensorimotor speed. Those differences were most pronounced in the 12 to 14 age range. "It's quite striking how complementary the brains of women and men really are," said Dr. Ruben Gur. "Detailed connectome maps of the brain will not only help us better understand the differences between how men and women think, but it will also give us more insight into the roots of neuropsychiatric disorders, which are often sex related." Next steps are to quantify how an individual's neural connections are different from the population; identify which neural connections are gender specific and common in both; and to see if findings from functional magnetic resonance imaging (fMRI) studies fall in line with the connectome data Professional Counselor Continuing Education ### Co-authors of the study include Madhura Ingalhalikar, Alex Smith, Drew Parker, Theodore D. Satterthwaite, Mark A. Elliott, Kosha Ruparel, and Hakon Hakonarson of the Section of Biomedical Image Analysis and the Center for Biomedical Image Computing and Analytics. This study was funded by in part by the National Institutes of Mental Health: MH089983, MH089924, MH079938, and MH092862.

PTSD raises risk for obesity in women

Women with PTSD gain weight more rapidly than women without disorder Women with post-traumatic stress disorder (PTSD) gain weight more rapidly and are more likely to be overweight or obese than women without the disorder, find researchers at Columbia University's Mailman School of Public Health and Harvard School of Public Health. It is the first study to look at the relationship between PTSD and obesity over time. Results appear online in JAMA Psychiatry. One in nine women will have PTSD at sometime over the course of their lifetime—twice as often as men. Women are also more likely to experience extreme traumatic events like rape that carry a high risk for the disorder. "PTSD is not just a mental health issue," says study senior author Karestan Koenen, PhD, Mailman School associate professor of Epidemiology. "Along with cardiovascular disease and diabetes, we can now add obesity to the list of known health risks of PTSD." PTSD - Clinical Practice Guideline for Management of Post Traumatic Stress CEU Course "The good news from the study is that it appears that when PTSD symptoms abate, risk of becoming overweight or obese is also significantly reduced," says first author Laura D. Kubzansky, PhD, Professor of Social and Behavioral Sciences at Harvard School of Public Health. However, despite the growing evidence of potential far-reaching problems associated with PTSD, it's estimated that only half of women in the United States with the disorder are ever treated. "Hopefully, wider recognition that PTSD can also influence physical health will improve this statistic, leading to better screening and treatments, including those to prevent obesity," says Dr. Kubzansky. While it's known that women with PTSD have high rates of obesity, it has been unclear whether PTSD was actually driving the weight gain. To explore the issue, the researchers analyzed data collected from 50,504 women, aged 22-44 years, taking part in the Nurses' Health Study II between 1989 and 2009. Participants were asked about the worst trauma they experienced and if they had related post-traumatic stress symptoms. The threshold for PTSD was the persistence of four or more symptoms over a month or longer. Common symptoms include re-experiencing the traumatic event, feeling under threat, social avoidance, and numbness. Normal-weight women who developed PTSD during the study period had 36% increased odds of becoming overweight or obese compared with women who experienced trauma but had no symptoms of PTSD. The higher risk was evident even for women with sub-threshold symptoms levels and remained after adjusting for depression, which has also been proposed as a major risk factor for obesity. In women with PTSD that began prior to the study period, body mass index increased at a more rapid pace than women without PTSD. The observed effect of PTSD on obesity is likely stronger in the general population of women than in nurses, notes Dr. Koenen. "Nurses are great for studies because they report health measures like BMI with a high degree of accuracy. But they are also more health conscious and probably less likely to become obese than most of us, which makes these results more conservative than they would otherwise be." Symptoms of PTSD rather than the trauma itself seemed to be behind the weight gain. "We looked at the women who developed PTSD and compared them to women who experienced trauma but did not develop PTSD. On the whole, before their symptoms emerged, the rate of change in BMI was the same as the women who never experienced trauma or did experience trauma but never developed symptoms," says Dr. Kubzansky. How exactly does PTSD lead to weight gain? The biological pathway is unknown, but scientists have a number of guesses. One is through the over-activation of stress hormones. PTSD may lead to disturbances in functioning of the hypothalamic-pituitary-adrenal axis and the sympathetic nervous system, each of which are involved in regulating a broad range of body processes, including metabolism. Another is through unhealthy behavior patterns that may be used to cope with stress. Ongoing research is looking at whether PTSD increases women's preference for processed foods and decreases their likelihood of exercising Social Worker Continuing Education ### Co-authors include Pula Bordelois, MPH, and Andrea Roberts, PhD, at Harvard School of Public Health; Hee Jin Jun, DrPH, at the Channing Division of Network Medicine at Brigham and Women's Hospital; Noah Blustone, BA, at Harvard Medical School and Boston University; and Magdalena Cerda, DrPH, at Columbia's Mailman School. The study was supported by grants from the National Institute of Mental Health to Dr. Koenen (MH078928 and MH093612). The authors declare no conflict of interest.