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

Area of Science:

• Neuroscience
• Neurology
• Psychology

Background:

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

Purpose of the Study:

• To investigate abnormalities in brain networks and autonomic mechanisms involved in emotional processing in individuals with severe TBI.
• To determine if functional magnetic resonance imaging (fMRI) and pupillary light reflex (PLR) can identify these alterations.

Main Methods:

• A cross-sectional study compared 26 individuals with chronic severe TBI to 15 healthy controls.
• fMRI assessed brain processing of emotional music and resting-state functional connectivity of intrinsic brain networks (salience, limbic, default mode).
• Pupillary light reflex (PLR) measured autonomic function (parasympathetic and sympathetic).

Main Results:

• TBI participants showed reduced left insula activation to emotional music compared to controls.
• Resting-state fMRI revealed decreased connectivity in the salience network, caudate, and hippocampus in TBI.
• Exploratory analyses indicated reduced connectivity between default mode and limbic networks in TBI.
• Pupillary light reflex measurements showed blunted dark-adaptation responses in TBI individuals.

Conclusions:

• Chronic severe TBI is associated with altered brain network connectivity and sympathetic dysfunction.
• These neuro-autonomic alterations may represent key neural mechanisms contributing to emotional dysregulation after TBI.