Leila Montaser Kouhsari, United States of America

Stanford University Neurology
Dr. Montaser Kouhsari is a board-certified, fellowship-trained movement disorders neurologist and clinical assistant professor at Stanford University. Her clinical interests include treating cognitive, motor, and non-motor impairments due to Parkinson's disease, atypical Parkinsonism (Multiple System Atrophy, Progressive Supranuclear Palsy, Cortical Basal Syndrome), tremor, and ataxia. Dr. Montaser Kouhsari also assesses and manages Deep Brain Stimulations (DBS) treatment for Parkinson's disease and tremor. Her research interests include underlying mechanisms through which Parkinson's disease affects memory, executive function, and decision-making. She is also investigating the role of cognition as a biomarker for early diagnosis of movement disorders. Before joining Stanford University, Dr. Montaser Kouhsari was a fellow in the movement disorders center at Columbia University and Zuckerman Institute. She completed her post-doctoral training in neuroimaging of cognitive processes such as decision-making at California Institute of Technology (Caltech) and her neurology residency at the Icahn School of Medicine at Mount Sinai in New York City. She earned her M.D. from Iran University of Medical Sciences (IUMS) and her Ph.D. in cognitive psychology from New York University (NYU). Dr. Montaser Kouhsari's work has appeared in the Journal of Neuroscience, Nature Neuroscience, Neuropsychologia, Journal of Vision, and Vision Research. She has been featured in Neurology Today news. She has presented at meetings held by the American Academy of Neurology (AAN), the American Neurological Association (ANA), Society for Neuroscience (SFN), and the Movement Disorders Society (MDS).

Presenter of 2 Presentations

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
Session Icon
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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