# Morning Light Treatment for Traumatic Stress: the Role of Amygdala Reactivity

> **NIH NIH R61** · UNIVERSITY OF MICHIGAN AT ANN ARBOR · 2020 · $751,057

## Abstract

ABSTRACT
Exposure to trauma can lead to posttraumatic stress disorder (PTSD), depression and anxiety. Although
therapies exist for traumatic stress, many individuals fail to receive treatment or remain symptomatic despite
treatment. New treatments are needed for traumatic stress that target underlying mechanisms of the pathology
and offer a safe and acceptable alternative. Morning bright light has good potential as a novel non-invasive,
low risk treatment for traumatic stress. Morning bright light treatment has been shown to reduce depression,
anxiety, and PTSD symptoms (including our own pilot data). However, no studies are exploring the therapeutic
mechanisms of bright light treatment for traumatic stress. Retinal circadian photoreceptors transmit light to the
brain, including direct projections to the amygdala. In healthy controls, a 3-week morning bright light treatment
reduced amygdala reactivity to an emotional faces fMRI task. Amygdala reactivity to negative cues is linked to
traumatic stress symptoms, and reduces after successful treatment. Thus, morning bright light treatment may
reduce traumatic stress by reducing amygdala reactivity. Using a transdiagnostic approach, we will enroll
subjects who have experienced a criterion A trauma in the past 5 years and display significant mood and
arousal symptoms. We will use the commercially available Retimer® bright light device, which optimizes the
therapeutic light wavelength. Treatment adherence will be objectively assessed. In the R61 phase, 66 subjects
will be randomized to 4 weeks of bright morning light at 3 different doses: 15 min or 30 min or 1 hour/day.
Amygdala reactivity (probed with fMRI emotional faces task) will be assessed at 3 time points: baseline, 2
weeks, and 4 weeks. We will test for a dose-response relationship between duration of daily morning light
pulse and change in amygdala reactivity from baseline to 2 and 4 weeks. R61 Aim (Target Engagement):
establish a significant dose response relationship between duration of daily morning light pulse and reduction
from baseline in amygdala reactivity at week 2 and/or week 4. Morning bright light must induce a meaningful
reduction (d≥0.5) in amygdala reactivity to proceed to the R33 (the go/no-go criteria). In the R33 phase, 122
subjects will be randomized to bright (active) vs. dim (credible and biologically inactive placebo) morning light,
with optimal treatment duration derived from the R61 phase (minimal duration of daily morning light pulse that
elicits the earliest meaningful reduction of d≥0.5 in amygdala reactivity). R33 Aim 1 (Functional Outcomes):
establish the effect of morning bright vs. dim (placebo) light treatment on traumatic stress symptoms using
standard and transdiagnostic clinical measures. R33 Aim 2: establish change in amygdala reactivity as a
predictor of traumatic stress symptom improvement. This project will be the first to establish if anatomical links
between the retinal circadian photoreceptors and amygd...

## Key facts

- **NIH application ID:** 9993606
- **Project number:** 5R61MH117157-02
- **Recipient organization:** UNIVERSITY OF MICHIGAN AT ANN ARBOR
- **Principal Investigator:** Helen Julia Burgess
- **Activity code:** R61 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $751,057
- **Award type:** 5
- **Project period:** 2019-08-15 → 2022-05-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9993606

## Citation

> US National Institutes of Health, RePORTER application 9993606, Morning Light Treatment for Traumatic Stress: the Role of Amygdala Reactivity (5R61MH117157-02). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/9993606. Licensed CC0.

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