Reward network dysfunction is associated with cognitive impairment after stroke.

Area of Science:

• Neuroscience
• Rehabilitation Medicine
• Behavioral Science

Background:

• Stroke survivors frequently exhibit apathy and anhedonia, symptoms linked to reward system dysfunction.
• Reward processing is crucial for learning, yet its impact on stroke patient rehabilitation remains under-explored.
• Understanding reward system alterations is key to addressing motivational deficits post-stroke.

Purpose of the Study:

• To investigate reward behavior, learning capacity, and brain network connectivity in acute stroke survivors.
• To determine the relationship between reward sensitivity, learning deficits, and functional brain connectivity after stroke.
• To inform tailored rehabilitation approaches by identifying stroke-induced reward network dysfunction.

Main Methods:

• Assessed reward behavior and learning using the Monetary Incentive Delay (MID) task in 28 acute stroke patients and 26 controls.
• Measured brain functional network connectivity using magnetoencephalography (MEG) during the MID task.
• Employed coherence analyses to evaluate reward-related changes in brain network connectivity.

Main Results:

• Stroke survivors demonstrated significantly lower reward sensitivity and impaired learning improvement compared to controls.
• MEG analyses revealed reduced network connectivity in frontal and temporoparietal regions among stroke survivors.
• Reduced reward sensitivity, learning deficits, and altered brain connectivity were closely interrelated in the stroke group.

Conclusions:

• Acute stroke induces significant dysfunction in the brain's reward network, impacting behavioral systems.
• These findings highlight a general pattern in mild strokes, irrespective of lesion location.
• Identifying reduced learning capacity and reward system impairment is crucial for developing individualized stroke rehabilitation programs.