HOW PARKINSON’S DISEASE AFFECTS PERCEPTUAL AND VALUE-BASED DECISIONS

Session Type
SYMPOSIUM
Date
12.03.2021, Friday
Session Time
12:00 - 14:00
Room
On Demand Symposia B
Lecture Time
12:30 - 12:45
Presenter
  • Leila Montaser Kouhsari, United States of America
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On-Demand

Abstract

Aims

Parkinson's disease (PD) is a neurodegenerative disease causing deficits in decision‐making. However, the mechanism by which PD affects decisions remains unknown. Computational modeling has been used to study perceptual decisions that are based on sensory evidence and value-based decisions that depend on internal preferences in healthy controls (HCs). Our experiments aimed to characterize decision behavior in PD patients in an on and off dopaminergic state using computational modeling.

Methods

PD patients on and off dopaminergic medication and age‐matched HCs performed a value‐based decision task and made choices between pairs of familiar food items. The value of each item was determined in advance using a separate food‐rating task. The same participants also made perceptual decisions about the color of random dynamic dots with different color coherence. The reaction time (RT) and choice performance in both tasks were measured and fitted with a drift‐diffusion model (DDM).

Results

Our results revealed that patients off‐medication showed similar accuracies to HCs in making value‐based and perceptual decisions but were faster than HCs. Furthermore, patients’ RTs were significantly longer when they were on‐medication and were making value-based decisions but not when making perceptual decisions.

Conclusions

We conclude that the threshold for decision-making is less in patients than HCs, indicating a less deliberative decision process. Moreover, the decision threshold is less when patients are off‐medication than when they are on‐medication, showing that dopaminergic medication increases the decision threshold to allow more deliberation. We propose that dopaminergic medication affects deliberation process by strengthening frontostriatal and hippocampal-striatal connections.

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