Emotional Processing after Severe Traumatic Brain Injury: Insights from Functional MRI and Pupillometry

Area of Science:

• Neuroscience
• Psychology
• Medical Imaging

Background:

• Emotional dysfunction is a common outcome of severe traumatic brain injury (TBI).
• The underlying neural and autonomic mechanisms of emotional dysregulation post-TBI are not well understood.

Purpose of the Study:

• To investigate abnormalities in brain network and autonomic mechanisms involved in emotional processing in individuals with chronic severe TBI.
• To explore the relationship between brain network connectivity, autonomic function, and emotional processing deficits in TBI.

Main Methods:

• Cross-sectional study comparing severe TBI (n=26) and healthy controls (n=15).
• Functional MRI (fMRI) for emotional stimuli processing and resting-state functional connectivity (salience, limbic, default mode networks).
• Pupillary light reflex (PLR) to assess autonomic function (parasympathetic and sympathetic).

Main Results:

• TBI group showed reduced left insula activation to emotional music compared to controls.
• Decreased resting-state functional connectivity was observed in the salience network, caudate, and hippocampus in TBI.
• Reduced connectivity between default mode and limbic networks was found in TBI.
• Blunted dark-adaptation responses in PLR indicated sympathetic dysfunction in the TBI group.

Conclusions:

• Chronic severe TBI is associated with altered brain network connectivity and autonomic dysfunction.
• These neurophysiological alterations may underlie emotional dysregulation observed in TBI survivors.
• Findings highlight potential neural targets for interventions aimed at improving emotional outcomes after TBI.