Sexual violence can be a scarring experience that takes a mental, physical, and emotional toll on victims. Now, a recent study published in the journal Scientific Reports suggests early exposure to rape, attempted rape, and sexual aggression can negatively impact cognitive function and even maternal behaviors later in life.

"We know very little about the brain mechanisms that account for the increase in depression and mood disorders among women who experience sexual trauma and aggression," said lead author Tracey Shorts, a professor in the Department of Psychology and Center for Collaborative Neuroscience in the School of Arts and Sciences at Rutgers, in the press release.

Traditionally, lab models used to measure stress in animals have focused on males and failed to accurately reflect ways females respond to stress. There’s no established lab animal model for studying the effects of sexual violence and behavior on brain function in females, yet sexual aggression and violence is a problem for women in many places, including the United States. Worldwide, 30 percent of women have experienced physical or sexual assault by an intimate partner, according to the World Health Organization.

To observe what occurs in the female brain during and after sexual violence, Shors and her colleagues paired a pubescent rodent female daily for 30 minutes with a sexually experienced adult male. During the experiment, the male tracks the region around the anus and genitals of the female as she escapes from "pins." A "pin" is when an adult male effectively restrains a female either by sitting on top of her or turning her over on her back and using his paws to hold her down. The researchers developed a research model they called Sexual Conspecific Aggressive Response to capture the females’ response.

The findings revealed concentrations of the stress hormone corticosterone were significantly elevated during and after the experience. Moreover, females who were exposed to the adult male during puberty did not perform well when it came to an associative learning task. Most of those who were exposed to the adult male did not learn to care for offspring over the course of 17 days. They expressed minimal maternal behaviors and had fewer newly-generated cells in their hippocampus, the brain’s center of emotion, memory, and the autonomic nervous system.

"This study is important because we need to understand how sexual aggression affects all species," said Shors.

Little is known about the brain mechanisms that contribute to the increase in depression and other mood disorders in women who experience sexual trauma and aggression. Without an animal model like the one Shors has created, researchers are limited in the types of studies they can conduct. This is important since it’s assumed the effects of stress learning and neuronal function in lab animals reflect changes that could occur in women who experience stressful life events.

Aversive experiences like sexual aggression do have mental health implications that can prevent women’s ability to learn and concentrate. Women who have been exposed to severe childhood sexual or physical abuse often suffer from post-traumatic stress disorder (PTSD).

This is associated with a decrease in volume in the amygdala, the brain’s center for emotions, emotional behavior, and motivation, and in the hippocampus, as well as an increase in learning deficits. Furthermore, children of women who suffer from PTSD are at a greater risk for traumatic experiences, which can lead to psychological aggression and other developmental conditions.

The adolescent brain is very plastic and vulnerable to stressful life experiences. Typically, the hippocampus produces thousands more cells each day during puberty than in adulthood. However, cell production can decrease due to a stressful experience.

A gendered focus on the impact of sexual violence on the brain and new approaches such as Shors’ mouse model will allow researchers to develop clinical interventions to help girls and young women recover from sexual violence and trauma.

Source: Shors TJ, Tobόn K, Durham DM et al. Sexual Conspecific Aggressive Response (SCAR): A Model of Sexual Trauma that Disrupts Maternal Learning and Plasticity in the Female Brain. Scientific Reports. 2016.