Findings may identify potential pathway for race-related health disparities

Racial discrimination was associated with greater neural responses to threat in Black women when they were exposed to images of trauma, a small functional MRI (fMRI) study showed.

Black women with greater experiences of racial discrimination had significantly more activity in the ventromedial prefrontal cortex and middle occipital cortex networks when their attention to trauma-related images involving assault and gun violence was compared against neutral images of people, nature, or object stimuli, Negar Fani, PhD, of Emory University in Atlanta, and co-authors reported.

Results were robust after controlling for post-traumatic stress disorder (PTSD) symptoms and trauma exposure.

“These findings suggest that experiences of racial discrimination associate with disproportionately greater response in brain regions associated with emotion regulation and fear inhibition and visual attention,” Fani and colleagues wrote in JAMA Psychiatry.

“Frequent racism experienced by Black individuals may potentiate attentional and regulatory responses to trauma-relevant stressors and lead to heightened modulation of regulatory resources. This may represent an important neurobiological pathway for race-related health disparities.”

“A heightened attentional detection of racism-related threat, as well as increased efforts to regulate response to these threats over time, may emerge in people who have been exposed to chronic racism,” they added.

The researchers studied 55 Black women with a mean age of about 38 (range 21-61) who were recruited from a National Institutes of Health (NIH)–funded study of attentional control in women with PTSD in inner-city Atlanta. The study was conducted between May 2015 and July 2019.

The fMRI task was the affective Stroop task, which involved pushing a button to identify whether 3, 4, 5, or 6 numbers were displayed. Trauma-relevant, positive, and neutral scenes were viewed before and after each stimulus. Statistical analyses were conducted at a whole-brain, voxelwise level.

Evaluations included:

  • Traumatic Events Inventory (TEI; number of times a person was exposed to trauma with range 0-112): mean frequency 33.0.
  • PTSD Symptom Scale (PSS; range 0-51): mean score 15.4, consistent with moderate levels of current PTSD symptoms.
  • Experiences of Discrimination Questionnaire (EOD; number of situations for which each participant reported having unfair treatment for a racial reason, range 0-9): mean score 2.35.

EOD scores were moderately correlated with PTSD symptoms (r=0.36, P=0.009), but not with age (r=0.20, P=0.15) or TEI frequency (r=–0.02, P=0.89). A greater number of racial discrimination experiences (EOD score) was associated with increased blood oxygen level-dependent responses in visual attention areas (middle occipital cortex) and in nodes of emotion regulation and fear inhibition (ventromedial prefrontal cortex) during trauma-relevant versus neutral images.

Fani and colleagues also found significantly fewer affective Stroop task errors on trauma-relevant tasks after adjustment for PTSD and TEI frequency. Response times did not show similar associations.

“Experiences of racism were not associated with deficiencies in attentional control, but rather with heightened activation in emotion regulation and threat inhibition regions, which can disproportionately encumber and drain these resources over time,” Fani and co-authors observed.

“Some studies have shown that racist experiences adversely affect performance on attention and executive functioning tasks, such as the Stroop task,” they added. “Although discriminatory experiences were not associated with poorer Stroop performance in our study, it is possible that, in participants with more discriminatory experiences, task performance was preserved at the cost of efficiency in regulatory networks. The use of compensatory strategies at the cost of efficiency is also observed in the context of general anxiety.”

“One of the unique contributions of the study findings by Fani and colleagues is that, while controlling for post-traumatic stress disorder symptoms and other lifetime trauma exposure, the significant associations they found between racial discrimination and neural response patterns remained,” noted Robert Motley Jr., PhD, of Boston College, and Cynthia Rogers, MD, of Washington University in St. Louis, in an accompanying editorial.

“According to Fani and colleagues, this is the first study to examine the unique association between racial discrimination and neural response patterns throughout the brain during attention to threat cues for a sample of Black individuals with high trauma exposure, although other studies have reported an association between experiencing racial discrimination in a social interaction task and threat-associated activation in the ventromedial prefrontal cortex,” they added.

A 2009 meta-analysis concluded that perceived discrimination leads to significantly heightened stress responses, participation in unhealthy and nonparticipation in healthy behaviors, and has a significant negative effect on both mental and physical health.

“Our findings complement a growing literature on the associations between disparate stressor exposure and neurobiological outcomes in marginalized racial/ethnic groups,” Fani and colleagues wrote.

“The proportionally greater ventromedial prefrontal cortex response observed in association with discrimination may represent a resilient adaptation to stress,” they added.

“It is possible that the findings observed in this study indicate a relatively enhanced ability to manage stress related to discrimination experiences,” they continued. “Coupled with the behavioral data that demonstrated better attention performance on threat-relevant affective Stroop task trials in association with discrimination experiences, the functional MRI findings may illustrate a biological marker of resilience and/or protective adaptation in the face of racism-related stressors in this sample of Black women in the U.S. exposed to trauma.”

Limitations include a small cohort made up exclusively of Black women. “Future studies should seek to replicate these findings in larger, racially, ethnically, and sexually diverse cohorts,” the researchers wrote.

  1. Racial discrimination was associated with greater neural responses to threat in Black women when they were exposed to images of trauma, a small functional MRI study showed.

  2. Results were robust after controlling for post-traumatic stress disorder symptoms and other trauma exposure.

Paul Smyth, MD, Contributing Writer, BreakingMED™

This study was supported by grants from the National Institute of Mental Health, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Emory Medical Care Foundation, American Psychological Association, Society for Clinical Neuropsychology, National Cancer Institute, and Frazier Foundation Grant for Mood and Anxiety Research at McLean Hospital.

Fani reported receiving grants from the National Institutes of Health during the conduct of the study.

Motley and Rogers reported no conflicts of interest.

Cat ID: 146

Topic ID: 87,146,585,730,192,146,925