Although it has long been known that there is a difference in prevalence of certain psychiatric disorders between the sexes, there is very little neurobiological information concerning why such differences occur. Anxiety disorders, major depression, and eating disorders are more common in females, while attention deficit disorder, Tourette Syndrome, and substance abuse are more common in men. Understanding the biological basis of these differences is important, as it can lead to a more sophisticated understanding of the pathophysiology of these disorders, including the role of hormonal and genetic influences, and can lead to more targeted diagnostic and therapeutic strategies. Finally, it is important for interpreting the exponentially increasing literature using functional imaging (which usually does not take sex into account). Currently, the FNL is examining sex differences and gender biology using several different strategies.
Brain Function and Structure Across the Menstrual Cycle and in PMDD
Examination of emotional and control systems across the menstrual cycle can also help in understanding the predisposition of women to certain psychiatric disorders. The FNL has found that these systems function differentially across the cycle, even in women with no premenstrual symptoms. By investigating premenstrual dysphoric disorder (PMDD), a psychiatric diagnosis at the extreme end of the premenstrual syndrome emphasizing mood symptoms, it is also hoped that new light will be shed on women’s vulnerability to anxiety and depression. In addition to assessing functional differences, our lab has demonstrated short-term structural plasticity of the hippocampus across the menstrual cycle in humans, which also has implications for understanding alterations in cognition and behavior across the menstrual cycle.
The Male Brain
In addition to studying women and sex differences, the FNL is collaborating with Dr. Shalinder Bhasin and his team to study hormonal effects on male brain function
Basaria S, Jasuja R, Huang G, Wharton W, Pan H, Pencina K, Li Z, Travison T, Bhawan J, Gonthier R, Labrie F, Dury A, Serra C, Papazian A, Leary M, Amr S, Storer T, Stern E*, Bhasin S*. Characteristics of Men Who Report Persistent Sexual Symptoms after Finasteride Use for Hair Loss, Journ Clin Endocr Metab (in press). *shared Senior Authors
Protopopescu X, Pan H, Tuescher O, Root J, Cheng L, Altemus M, Polanecsky M, McEwen B, Stern E, Silbersweig D. Toward a functional neuroanatomy of premenstrual dysphoric disorder: differential amygdalar, orbitofrontal and ventral striatal activity. J Affective Disorders, 108: 87-94, 2008.
Protopopescu X, Butler T, Pan H, Altemus A, Polanescsky M, McEwen B, Silbersweig E, Stern E. Hippocampal structural changes across the menstrual cycle. Hippocampus, 18:985-8, 2008.
Butler T, Imperato-McGinley j, Pan H, Voyer D, Cunningham-Bussel AC, Chang L, Zhu Y-S, Cordero J, Stern E, Silbersweig D. Sex specificity of ventral anterior cingulate cortex suppression during a cognitive task. Human Brain Mapping, 28(11): 1206-1212, 2007.
Butler T, Pan H, Imperato-McGinley J, Voyer D, Cunningham-Bussell A, Cordero J, Zhu Y-S, Silbersweig D, Stern E. A network approach to fMRI condition-dependent cognitive activation studies as applied to understanding sex differences. Clinical Neurosciences Research 6(6):391-98, 2007.
Voyer D, Butler T, Cordero J, Brake B, Silbersweig D, Stern E, & Imperato-McGinley J. The Relation between Computerized and Paper-and-Pencil Mental Rotation Tasks: A Validation Study. Journal of Clinical and Experimental Neuropsychology 28 (6): 928-39, 2006.
Butler T, Imperato-McGinley J, Pan H, Voyer D, Cordero, Xhu Y, Stern E, Silbersweig D. Sex differences during mental rotation: Top down versus bottom up processing. Neuroimage, 32:445-456, 2006.
Butler T, Pan H, Epstein J, Protopopescu X, Tuescher O, Goldstein M, Cloitre M, Yang Y, Phelps E, Gorman J, Ledoux J, Stern E, Silbersweig D. Fear-related activity in subgenual anterior cingulate differs between men and women. Neuroreport 16: 1233-1236, 2005.
Protopopescu X, Pan H, Altemus M, Tuescher O, Polanecsky M, McEwen B, Silbersweig D, Stern E. Orbitofrontal cortex activity related to emotional processing changes across the menstrual cycle. Proc Natl Acad Sci USA (PNAS), 102(44): 16060-5, 2005.