Photo of Nathaniel G. Harnett, PhD

Nathaniel G. Harnett, PhD

McLean Hospital Title
  • Director, Neurobiology of Affective and Traumatic Experiences Laboratory

Harvard Medical School Title
  • Assistant Professor of Psychiatry

Biography

Nathaniel G. Harnett, PhD, is a neuroscientist whose research is focused on understanding the brain basis for why some people are more likely to develop stress-related disorders, such as post-traumatic stress disorder (PTSD), after trauma. His current work leverages magnetic resonance imaging (MRI) techniques—including functional MRI, structural MRI, and diffusion weighted imaging—to identify multimodal neural signatures of PTSD susceptibility in the acute aftermath of trauma exposure.

The overarching emphasis of Dr. Harnett’s work is on elucidating neural circuitry linked to acute and long-term development of post-traumatic syndromes and identifying robust and generalizable neurobiological targets for early intervention and treatment. Ultimately, the goal of this research is to develop predictive and preventative neuroscience-based techniques to reduce the prevalence of trauma and stress-related disorders.

Research Focus:

Dr. Harnett’s research investigates the neurobiological mechanisms that underlie susceptibility to trauma and stress-related disorders.

Although many people will experience a traumatic event, only a fraction will go on to develop post-traumatic stress disorder (PTSD). Identifying brain processes that control whether someone goes on to develop PTSD has important implications for early prediction and treatment options.

To these ends, Dr. Harnett’s laboratory takes a multidimensional approach to studying the human brain by integrating cognitive and psychometric assessment, psychophysiology, and multimodal neuroimaging techniques with individuals recently exposed to traumatic events.

By collecting granular information on the brain and body soon after traumatic events, the lab hopes to be able to tie these metrics with individuals’ future expression of PTSD symptoms.

The lab’s previous work highlights a role for brain circuitry involved in processing and understanding threats in our environment as important for predicting individuals’ likelihood of developing PTSD after trauma. Interactions between the frontal lobes and the amygdala in the early aftermath of trauma appear to be critical for how an individual responds to traumatic stress over time.

More recent work from Dr. Harnett’s lab suggests brain regions important for processing sensory information—particularly visual stimuli—play a unique role in the development of PTSD after trauma. Further, these systems appear to interact with regions critical for processing threat. Understanding both systems may help to improve assessment of PTSD susceptibility.

However, the lab’s work also highlights that the pretraumatic factors—the burdens people bring with them to the traumatic event—vary by individual, but also by racial/ethnic group.

Dr. Harnett and his collaborators have shown that structural inequities and race-related interpersonal stressors affect brain regions involved in PTSD development. Further, these stressors directly modulate how people respond to subsequent traumatic stress.

Structural and interpersonal racism therefore have direct neurobiological effects relevant to our understanding of how PTSD develops.

Personnel:
  • Grace Rowland, Clinical Research Assistant
  • Elisabeth Kate Webb, PhD, Research Fellow
Collaborators:
Selected Publications:

Harnett NG, Stevens JS, Fani N, van Rooij SJH, Ely TD, Michopoulos V, Hudak L, Rothbaum AO, Hinrichs R, Winters SJ, Jovanovic T, Rothbaum BO, Nickerson LD, Ressler KJ. Acute posttraumatic symptoms are associated with multimodal neuroimaging structural covariance patterns: a possible role for the neural substrates of visual processing in posttraumatic stress disorder. Biological Psychiatry. Cognitive Neuroscience and Neuroimaging. 2022;7(2):129-138.

Harnett NG, Finegold KE, Lebois LAM, van Rooij SJH, Ely TD, Murty VP, Jovanovic T, Bruce SE, House SL, Beaudoin FL, An X, Zeng D, Neylan TC, Clifford GD, Linnstaedt SD, Germine LT, Bollen KA, Rauch SL, Haran JP, Storrow AB, Lewandowski C, Musey PI, Hendry PL, Sheikh S, Jones CW, Punches BE, Kurz MC, Swor RA, Hudak LA, Pascual JL, Seamon MJ, Harris E, Chang AM, Pearson C, Peak DA, Domeier RM, Rathlev NK, O’Neil BJ, Sergot P, Sanchez LD, Miller MW, Pietrzak RH, Joormann J, Barch DM, Pizzagalli DA, Sheridan JF, Harte SE, Elliott JM, Kessler RC, Koenen KC, McLean SA, Nickerson LD, Ressler KJ, Stevens JS. Structural covariance of the ventral visual stream predicts posttraumatic intrusion and nightmare symptoms: a multivariate data fusion analysis. Translational Psychiatry. 2022;12(1):321.

Dumornay NM, Lebois LAM, Ressler KJ, Harnett NG. Racial disparities in adversity during childhood and the false appearance of race-related differences in brain structure. American Journal of Psychiatry. 2023;180(2):127-138.

PubMed search for Dr. Harnett

Education & Training

Degrees:
  • 2013 BA in Psychology, Ithaca College
  • 2018 PhD in Psychology, University of Alabama at Birmingham

Contact

Phone: 617.855.3526
Office Address: Belmont campus - Oaks Building, Room 334