Structural covariance of the ventral visual stream predicts posttraumatic intrusion and nightmare symptoms: a multivariate data fusion analysis

Translational Psychiatry, 2022 · DOI: https://doi.org/10.1038/s41398-022-02085-8 · Published: August 22, 2022

Simple Explanation

Trauma survivors often vividly re-experience visual components of trauma memories, impacting their daily lives. This study investigates the role of visual brain circuitry, specifically the ventral visual stream, in posttraumatic stress disorder (PTSD). The research combined different types of brain scans (MRI) to identify a network in the ventral visual stream two weeks after trauma. The strength of this network was linked to intrusion symptoms and nightmares. The study suggests that the ventral visual stream's integrity is important in PTSD development, potentially influencing how trauma memories are stored and retrieved, and further that chronic engagement of this network may lead to reduced structural integrity which becomes a risk factor for lasting PTSD symptoms.

Study Duration

6 months

Participants

n = 278 trauma-exposed participants

Evidence Level

Longitudinal, multisite study

Key Findings

1
A structural covariance network (SCN) of the ventral visual stream (VVS) was identified, and its strength was positively associated with PTSD symptoms two weeks after trauma.
2
The strength of the VVS SCN was specifically linked to intrusion symptoms (flashbacks, re-experiencing) and the intensity of nightmares.
3
Greater loadings of the VVS SCN were negatively related to resting-state functional connectivity between an amygdala-hippocampal RSN and the inferior temporal gyrus.

Research Summary

This study investigated the role of the ventral visual stream (VVS) in PTSD using multimodal MRI data from trauma-exposed individuals. A structural covariance network (SCN) within the VVS was identified, and its strength was found to be associated with acute PTSD symptoms, intrusion symptoms, and nightmare intensity. Changes in the VVS SCN over time were related to PTSD symptom severity, suggesting a dynamic role for this visual pathway in the development and maintenance of PTSD.

Practical Implications

New avenues for research

Modulation of visual neural circuitry after trauma opens new avenues for future research and potential neuromodulation techniques to reduce PTSD symptoms and nightmares in the aftermath of trauma.

Understanding threat and visual processing circuitry

Uncovering the nature of interactions between canonical threat and visual processing circuitry may provide the most effective avenue for the identification of robust and generalizable neural signatures of trauma and stress-related disorders.

Early intervention targets

The findings suggest that interventions targeting the ventral visual stream early after trauma may help prevent the development of chronic PTSD.

Study Limitations

1
The present approach required participants to have complete MRI data across a number of features which reduced our sample size.
2
It is also worth noting that, although we observed unique associations between VVS SCN loadings and specific PTSD symptom dimensions at 2 weeks and 6 months, such symptom dimensions are highly correlated with one another.
3
Another limitation is the lack of a non-trauma-exposed sample.

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