Daijiworld Media Network - New Delhi
New Delhi, May 5: A groundbreaking study by researchers at the Indian Institute of Technology (IIT) Bombay has shed new light on how disrupted brain activity affects motivation and decision-making in people with Parkinson’s disease — a condition often associated with tremors and stiffness, but also with deeper cognitive challenges.
The study focused on how Parkinson’s impacts reward processing, a key brain function that helps people recognize and respond to pleasurable or goal-oriented stimuli. Using electroencephalography (EEG), the researchers found that Parkinson’s patients showed weaker "reward positivity" — a brain signal linked to attention, learning, and emotional response.
“Normally, the brain releases dopamine in bursts after receiving a reward,” explained Prof. Nivethida Thirugnanasambandam, who led the study. “But in Parkinson’s, these bursts are weaker. While dopamine medication raises overall dopamine levels, it doesn't replicate these natural bursts — which may explain why the drugs improve motor skills but not motivation or cognition.”
In the study, 28 Parkinson’s patients and 28 healthy individuals performed a reward-based task while their brain activity was monitored. Surprisingly, dopamine medication did not restore normal reward positivity, suggesting the need for additional treatments to address cognitive symptoms.
The team also discovered that Parkinson’s patients had reduced theta-gamma synchronisation — a type of brainwave coupling essential for learning and motivation. While medication helped partially restore this synchronisation, it wasn’t enough to fix the impaired reward system entirely.
The findings, according to the researchers, not only explain why Parkinson’s patients often experience apathy and poor decision-making but also highlight theta-gamma coupling as a potential biomarker for assessing cognitive decline in these patients.
The study paves the way for developing new therapies targeting cognitive functions, alongside current motor-symptom treatments.