Sexual Conspecific Aggressive Response (SCAR): A Model of Sexual Trauma that Disrupts Maternal Learning and Plasticity in the Female Brain

Abstract

Sexual aggression can disrupt processes related to learning as females emerge from puberty into young adulthood. To model these experiences in laboratory studies, we developed SCAR, which stands for Sexual Conspecific Aggressive Response. During puberty, a rodent female is paired daily for 30-min with a sexually-experienced adult male. During the SCAR experience, the male tracks the anogenital region of the female as she escapes from pins. Concentrations of the stress hormone corticosterone were significantly elevated during and after the experience. Moreover, females that were exposed to the adult male throughout puberty did not perform well during training with an associative learning task nor did they learn well to express maternal behaviors during maternal sensitization. Most females that were exposed to the adult male did not learn to care for offspring over the course of 17 days. Finally, females that did not express maternal behaviors retained fewer newly-generated cells in their hippocampus whereas those that did express maternal behaviors retained more cells, most of which would differentiate into neurons within weeks. Together these data support SCAR as a useful laboratory model for studying the potential consequences of sexual aggression and trauma for the female brain during puberty and young adulthood.

MAP Training My Brain™: Meditation Plus Aerobic Exercise Lessens Trauma of Sexual Violence More Than Either Activity Alone

“…Early studies in animal models reported that many new neurons die within weeks unless new and effortful learning occurs (Gould et al, 1999 ; Shors, 2014 ). It was later reported that pubescent female rats exposed to an aggressive adult male did not learn well and as such retained fewer cells (Shors et al, 2016 ). Because learning and aerobic exercise increase these neurogenic processes, again in rodent models (DiFeo and Shors, 2017 ; Vivar and van Praag, 2017 ), we proposed that mental and physical training may be particularly effective when done together (Curlik and Shors, 2013 ; Shors et al, 2014 ).…”

Sexually Dimorphic Risk Mitigation Strategies in Rats

“…That females exhibit an attenuation in fear and anxiety behaviors just before the estrus phase may be related to their evolutionary need to mate despite the potential violence commonly accompanying mating behavior in many animals ( West-Eberhard, 2014 ). Indeed, the presence of males, or just their odor, has been shown to elicit a stress response in rats ( Sorge et al, 2014 ; Shors et al, 2016 ). Thus, proestrus-related hormones may function to decrease female aversion to copulation, and its effects on fear learning in laboratory settings may be an artifact of such a function.…”

Sex differences in depression during pregnancy and the postpartum period

“…In young females, interaction with offspring seems to protect against adverse effects of stress on processes involved in memory and learning (Leuner and Shors, ). Additionally, there is evidence that expression of maternal behaviors is associated with survival of newly generated neurons in the hippocampus, emphasizing the important role of neurogenesis for adequate care of the offspring (Shors et al, ). Paternal neurogenesis has also been investigated in two biparental species, the California mouse and the prairie vole.…”