How the Brain Responds to Positive Emotions Is Key to Resilience After Trauma, World Trade Center Responder Research Shows

New research has uncovered that how the brain responds to anticipated rewards plays a key role in building psychological resilience after a traumatic experience. The findings from the new studyopens in new tab/window among 9/11 responders, appearing in Biological Psychiatry: Cognitive Neuroscience and Neuroimagingopens in new tab/window, published by Elsevier, support the premise that the capacity to notice and respond to positive information in the environment may buffer the negative effects of substantial trauma exposure.

Thousands of workers involved in rescue, recovery, and clean-up efforts after the events of September 11, 2001, showed remarkable resilience despite having experienced unprecedented trauma. In fact, resilience is a common trait of trauma-exposed individuals.

“We wanted to understand why some World Trade Center (WTC) responders and recovery workers developed chronic posttraumatic stress disorder (PTSD), while others maintained good psychological health despite experiencing similar extreme stressors during recovery efforts,” says co-lead investigator Robert H. Pietrzak, PhD, MPH, Professor of Psychiatry at Yale School of Medicine. “Most people recognize PTSD symptoms such as flashbacks, intrusive memories, and hypervigilance. However, PTSD can also diminish a person’s capacity to experience positive emotions, including happiness, enjoyment, and love.”

Psychological factors relying on the capacity for reward processing (positive emotions, optimism, hope) have long been linked to better stress resilience. However, the brain mechanisms underlying this link have rarely been investigated.

This study, conducted approximately two decades after 9/11 primarily among first responders with and without chronic WTC-related PTSD from the WTC Health Program General Responder Cohort, measured and mapped participants’ brain activity using functional MRI during a reward-based task.

Lead investigator Adriana Feder, MD, Professor of Psychiatry at the Icahn School of Medicine at Mount Sinai, points out, “Little is known about brain function during reward anticipation in resilient individuals. This study is unique in its focus on the function of reward circuitry in highly resilient individuals, compared with those with chronic PTSD and lower-exposed controls. All study participants have experienced the 9/11 WTC events and their aftermath, but the severity of exposure varied.”

Participants were divided into three groups:

1. Responders with chronic WTC-related PTSD.

2. Psychologically healthy trauma-exposed controls: 2a: Highly Resilient: Responders with substantial exposure to potentially traumatic elements of the 9/11 WTC events, such as finding human remains or being caught in the dust cloud. 2b: Lower WTC-Exposed: Responders who had minimal exposure to potentially traumatic elements during their WTC recovery effort work.

The Highly Resilient group had the strongest increase in activation in the brain areas related to how rewards are detected (the nucleus accumbens) and weighed (the ventromedial prefrontal cortex). This increase was significantly greater compared to both the PTSD group and the Lower-WTC Exposed group.

“Notably, when we surveyed participants about reward-related resilience factors like positive emotionality and hedonic experience, their responses only distinguished between responders who had PTSD, and those who did not,” says Saren Seeley, PhD, who conducted the neuroimaging analyses as a postdoctoral fellow working with Drs. Feder, Perez-Rodriguez, and Pietrzak at the Icahn School of Medicine at Mount Sinai. “This highlights that the brain imaging data captured something distinct from self-report.”

Editor-in-Chief of Biological Psychiatry: Cognitive Neuroscience and Neuroimaging Cameron S. Carter, MD, University of California Irvine School of Medicine, comments, “This is one of the first brain-imaging studies to compare how the brain responds to reward anticipation across groups of people who have experienced the same traumatic event, going beyond self-reported measures of positive emotions alone. It also highlights mechanisms of resilience in an important group to our country, first and other responders, e.g., construction workers, to the attack on the World Trade Center, 25 years after this traumatic event. Understanding how positive emotions are linked to psychological resilience can help guide clinical assessment and intervention in trauma-exposed populations.”

“One intriguing hypothesis that warrants future investigation is whether this protective neural capacity may be a modifiable therapeutic target, i.e., whether we can ‘train the brain’ to better anticipate positive outcomes to prevent or treat PTSD,” concludes co-lead investigator M. Mercedes Perez-Rodriguez, MD, PhD, Professor of Psychiatry at the Icahn School of Medicine at Mount Sinai.

Notes for editors

The article is "Differential Reward Circuitry Engagement During Anticipation in Highly Resilient World Trade Center Responders," by Saren H. Seeley, Zoe Schreiber, Agnes Norbury, Laurel S. Morris, Elisa Monti, Leah Cahn, Cindy J. Aaronson, Mary Kowalchyk, Jonathan M. DePierro, James W. Murrough, Emily R. Stern, Dennis S. Charney, Robert H. Pietrzak, M. Mercedes Perez-Rodriguez, and Adriana Feder (https://doi.org/10.1016/j.bpsc.2026.07.003opens in new tab/window). It appears online in Biological Psychiatry: Cognitive Neuroscience and Neuroimagingopens in new tab/window, published by Elsevier.

The article is openly available for 60 days at https://www.biologicalpsychiatrycnni.org/article/S2451-9022(26)00208-9/fulltextopens in new tab/window.

Copies of this paper are also available to credentialed journalists upon request; please contact Rhiannon Bugno at [email protected]opens in new tab/window. Journalists wishing to interview the study’s authors should contact Elizabeth Dowling, Senior Director, Public Affairs and Media, Mount Sinai Health System, at [email protected]opens in new tab/window.

This work was supported by the CDC National Institute for Occupational Safety and Health (U01OH011473) and the NIH National Institute on Mental Health (T32MH122394). This content is solely the responsibility of the authors and does not necessarily represent the official views of the CDC or NIH.

This work was supported in part through the computational and data resources and staff expertise provided by Scientific Computing and Data at the Icahn School of Medicine at Mount Sinai and supported by the Clinical and Translational Science Awards (CTSA) grant UL1TR004419 from the National Center for Advancing Translational Sciences. This work was also supported in part by the Ehrenkranz Laboratory for the Study of Human Resilience at the Icahn School of Medicine at Mount Sinai.

The authors’ affiliations and disclosures of financial relationships and conflicts of interest are available in the article.

Cameron S. Carter, MD, is Chair of the Department of Psychiatry & Human Behavior at the University of California Irvine School of Medicine. His disclosures of financial relationships and conflicts of interest are available hereopens in new tab/window.

About Biological Psychiatry: Cognitive Neuroscience and Neuroimaging

Biological Psychiatry: Cognitive Neuroscience and Neuroimagingopens in new tab/window is an official journal of the Society of Biological Psychiatryopens in new tab/window, whose purpose is to promote excellence in scientific research and education in fields that investigate the nature, causes, mechanisms and treatments of disorders of thought, emotion, or behavior. In accord with this mission, this peer-reviewed, rapid-publication, international journal focuses on studies using the tools and constructs of cognitive neuroscience, including the full range of non-invasive neuroimaging and human extra- and intracranial physiological recording methodologies. It publishes both basic and clinical studies, including those that incorporate genetic data, pharmacological challenges, and computational modeling approaches. The 2025 Journal Impact Factor^TM score, from Clarivate, for Biological Psychiatry: Cognitive Neuroscience and Neuroimaging is 4.9. www.sobp.org/bpcnniopens in new tab/window

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