Cheryl Sisk, Ph.D.
University Distinguished Professor, Neuroscience Program
Associate Dean for Faculty Development, College of Natural Science
Michigan State University
“Not the usual place and time: new neurons and glia are added to sexually dimorphic brain regions during puberty”
There is growing evidence that postnatally born neurons and glial cells are added to the rodent hypothalamus and amygdala. My talk will focus on the pubertal addition of cells to the anteroventral periventricular nucleus (AVPV) and posterodorsal medial amygdala (MePD), two sexually dimorphic cell groups that contribute to sex differences in reproductive function and social behaviors. Using BrdU as a cell birthdate marker, we initially observed sex differences in the pubertal addition of new cells that parallel sex differences in AVPV and MePD volume in rats: more pubertally born cells are added to the AVPV in females, whereas more are added to the MePD in males. These sex differences are eliminated by prepubertal gonadectomy, indicating that gonadal hormones drive sex differences in the pubertal maturation of AVPV and MePD. Using tfm mice that lack functional androgen receptors, we found that the sex difference in pubertally born MePD cells is androgen receptor-dependent. Other experiments investigated whether pubertally born cells are functionally incorporated into neural circuits mediating sex-specific behaviors. These experiments provide evidence that pubertally born AVPV cells contribute to the ovarian-hormone induced LH surge in female rats, and that pubertally born MePD cells are activated by social interactions in male hamsters and mice. We propose that the pubertal addition of new neurons and glia to sexually dimorphic cell groups is a potential mechanism underlying adolescent maturation of sex-specific reproductive function and social behaviors.
Friday, October 26, 2018, 11:00AM-12:00PM, LIB-110
University of North Texas Health Science Center
Fort Worth, Texas