Klabunde, M., Weems, C. F., Raman, M. and Carrion, V. G. (2016), The moderating effects of sex on insula subdivision structure in youth with posttraumatic stress symptoms. Depress Anxiety. doi:10.1002/da.22577
The insula is involved in interoceptive processing, emotion awareness, and attention to salient stimuli. Research suggests that these functions are specific—albeit overlapping—within insula subdivisions. Additional studies also imply that sexual dimorphism and different rates of development occur within these subdivisions in youth. The purpose of this study was to examine potential insula subdivision structure differences in youth with PTSD symptoms as compared to controls and test sex as a moderator of these differences.
Insula structure (volume, surface area, and thickness) was measured with structural magnetic resonance imaging (sMRI) and calculated using Freesurfer software. We compared insula structure across age- and sex-matched boys and girls with (30 with and 29 without) PTSD symptoms while also controlling for age and whole brain measurements.
Differences were specific to the insula's anterior circular sulcus. Within this subregion, boys with PTSD symptoms demonstrated larger volume and surface area than control boys, while girls with PTSD symptoms demonstrated smaller volume and surface area than control girls.
Findings indicate a potential neurobiological explanation for sex differences in youth with PTSD symptoms.
Brain scans of children and teenagers with post-traumatic stress disorder (PTSD) show structural differences between the sexes in one part of the insula, a brain region that detects cues from the body and processes emotions and empathy and helps to integrate feelings, actions, and several other brain functions.
“The insula appears to play a key role in the development of PTSD,” says Victor Carrion, professor of psychiatry and behavioral sciences at Stanford University. “The difference we saw between the brains of boys and girls who have experienced psychological trauma is important because it may help explain differences in trauma symptoms between sexes.”
Among young people who are exposed to traumatic stress, some develop PTSD while others don’t. People with PTSD may experience flashbacks of traumatic events; may avoid places, people and things that remind them of the trauma; and may suffer a variety of other problems, including social withdrawal and difficulty sleeping or concentrating.
Prior research has shown that girls who experienced trauma are more likely to develop PTSD than boys who experience trauma, but scientists have been unable to determine why…
There were no differences in brain structure between boys and girls in the control group. However, among the traumatized boys and girls, researchers saw differences in a portion of the insula called the anterior circular sulcus.
This brain region had larger volume and surface area in traumatized boys than in boys in the control group. But the region’s volume and surface area were smaller in girls with trauma than among girls in the control group.
“It is important that people who work with traumatized youth consider the sex differences,” says lead author Megan Klabunde, an instructor of psychiatry and behavioral sciences. “Our findings suggest it is possible that boys and girls could exhibit different trauma symptoms and that they might benefit from different approaches to treatment.”
The insula normally changes during childhood and adolescence, with smaller insula volume typically seen as children and teenagers grow older. Thus, the findings imply that traumatic stress could contribute to accelerated cortical aging of the insula in girls who develop PTSD, Klabunde says…
The work may help scientists understand how experiencing trauma could play into differences between the sexes in regulating emotions. “By better understanding sex differences in a region of the brain involved in emotion processing, clinicians and scientists may be able to develop sex-specific trauma and emotion dysregulation treatments,” the authors write.
To better understand the findings, the researchers say what’s needed next are longitudinal studies following traumatized young people of both sexes over time. They also say studies that further explore how PTSD might manifest itself differently in boys and girls, as well as tests of whether sex-specific treatments are beneficial, are needed.