Cognitive impairment and associated neurobehavioral dysfunction in post-COVID syndrome

Area of Science:

• Neuroscience
• Cognitive Psychology
• Infectious Diseases

Background:

• Post-COVID syndrome frequently presents with neuropsychiatric symptoms like chronic fatigue.
• The underlying mechanisms, particularly concerning the brain's reward system, are not well understood.
• Altered reward processing has been hypothesized as a potential cause of cognitive deficits in long COVID.

Purpose of the Study:

• To investigate whether post-COVID syndrome impairs reward processing or task-unspecific cognitive operations.
• To differentiate between deficits in reward circuitry versus broader cognitive control mechanisms.
• To explore the neural underpinnings of cognitive dysfunction in long COVID patients.

Main Methods:

• A cohort study comparing 24 post-COVID syndrome patients with 24 healthy controls.
• Utilized the Monetary Incentive Delay Task during functional magnetic resonance imaging (fMRI).
• Incorporated neuropsychiatric symptom questionnaires and pupillary measurements.

Main Results:

• Post-COVID patients exhibited slower task performance but intact behavioral reward circuit function.
• Increased influence of rewarding cues over time correlated with delayed left frontal gyrus activation.
• Slower reaction times were linked to reduced pupil diameter and higher pupillary unrest.

Conclusions:

• Post-COVID syndrome may not directly affect reward processing mechanisms.
• Findings suggest neural hypoarousal and temporally altered brain activity in frontal and task-unspecific regions.
• This points towards altered cognitive control and arousal states as key features of long COVID's neurological impact.