Emotional intensity and visual imagery in trauma nightmares map to posterior hippocampus connectivity
Meaghan McKenna, Kevin J. Clancy, Christine J So, Yara Pollmann, Boyu Ren, Isabelle M. Rosso
Translational Psychiatry August 3, 2026 DOI: 10.1038/s41398-026-04336-4 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Observational cohort Peer reviewed |
|---|---|
| Sample size | 66 |
| Population | Trauma-exposed adults (54 female) |
| Duration | Two weeks of daily ecological momentary assessments |
| Measures | ecological momentary assessments (EMAs) of nightmare properties |
| Topics | Dreaming |
| Key findings | Stronger posterior hippocampus-visual cortex connectivity was associated with greater visual detail and emotional intensity of nightmares, while anterior hippocampus-amygdala connectivity showed no significant associations. The authors propose this circuit as a neurotherapeutic target for trauma reexperiencing. |
Abstract
Distressing dreams or nightmares about a traumatic experience are common among trauma-exposed individuals and contribute to the maintenance of posttraumatic stress disorder (PTSD) symptoms. Like other intrusive reexperiencing symptoms, trauma-related nightmares are characterized by vivid sensory details and heightened emotional intensity. However, little is known about their underlying neurobiology, and whether it overlaps with that of diurnal reexperiencing symptoms. Therefore, this study aimed to elucidate neurobiological correlates of the phenomenology of trauma-related nightmares. Sixty-six trauma-exposed adults (54 female) completed daily ecological momentary assessments (EMAs) of the phenomenological properties of their trauma-related nightmares for two weeks, as well as resting-state functional magnetic resonance imaging. Pearson correlations examined associations between nightmare properties and functional connectivity within two a priori circuits previously implicated in trauma-related intrusions and episodic memory: 1) an affective circuit between the anterior hippocampus (aHPC) and amygdala (Amyg), and 2) a sensory circuit between the posterior hippocampus (pHPC) and visual cortex (VC). There were no significant associations between nightmare properties and aHPC-Amyg connectivity. In contrast, stronger pHPC-VC connectivity was associated with greater visual detail and emotional intensity of nightmares. These findings align with the established roles of the pHPC and VC in the detailed experience of episodic memory and suggest a novel role for these regions in the affective features of trauma nightmares. Overall, these findings provide support for overlapping neural correlates of the properties of trauma nightmares and diurnal reexperiencing symptoms. They offer additional evidence for a pHPC-VC circuit as a promising neurotherapeutic target for trauma reexperiencing symptoms.
Comparable studies
Other observational and cohort studies on dreaming, most cited first.
| Study | Year | Design | Participants |
|---|---|---|---|
| Lucid Dreaming: a State of Consciousness with Features of Both Waking and Non-Lucid Dreaming Student volunteers trained to become lucid and signal lucidity with horizontal eye... | 2009 | Observational study | n = 6 |
| Nightmare Prevalence, Nightmare Distress, and Self-Reported Psychological Disturbance Young adults with a mean age of 20 years | 2002 | Prospective observational study | n = 116 |
| Long-term effects of extreme situational stress on sleep and dreaming Survivors of traumatic events who complained of sleep disturbances, compared with... | 1987 | Case-control study | n = 11 |
| The relationship of nightmare frequency and nightmare distress to well‐being Adults who reported dreams | 2004 | Observational cohort | n = 147 |
| Dreaming in NREM Sleep: A High-Density EEG Study of Slow Waves and Spindles Healthy human subjects | 2018 | Observational cohort | n = 14 |