Patients with Parkinson's Disease Show Impaired Use of Priors in Conditions of Sensory Uncertainty.
Perceptual decisions arise after considering the available sensory evidence [1]. When sensory information is unreliable, a good strategy is to rely on previous experience in similar situations to guide decisions [2-6]. It is well known that patients with Parkinson's disease (PD) are impaired at value-based decision-making [7-11]. How patients combine past experience and sensory information to make perceptual decisions is unknown. We developed a novel, perceptual decision-making task and manipulated the statistics of the sensory stimuli presented to patients with PD and healthy participants to determine the influence of past experience on decision-making. We show that patients with PD are impaired at combining previously learned information with current sensory information to guide decisions. We modeled the results using the drift-diffusion model (DDM) and found that the impairment corresponds to a failure in adjusting the amount of sensory evidence needed to make a decision. Our modeling results also show that two complementary mechanisms operate to implement a bias when two sets of priors are learned concurrently. Asymmetric decision threshold adjustments, as reflected by changes in the starting point of evidence accumulation, are responsible for a general choice bias, whereas the adjustment of a dynamic bias that develops over the course of a trial, as reflected by a drift-rate offset, provides the stimulus-specific component of the prior. A proper interplay between these two processes is required to implement a bias based on concurrent, stimulus-specific priors in decision-making. We show here that patients with PD are impaired in these across-trial decision threshold adjustments.
The Fuster Laboratory of Cognitive Neuroscience, Department of Psychiatry and Biobehavioral Sciences, Department of Neurobiology, Semel Institute for Neuroscience and Human Behavior, Brain Research Institute, David Geffen School of Medicine at University of California, Los Angeles, 635 Charles Young Drive, Box 957332, Los Angeles, CA 90095, USA.
Alessandra
A
Perugini
Center for Neuroscience and Department of Neurobiology, Physiology, and Behavior, University of California, Davis, 1544 Newton Court, Davis, CA 95618, USA.
Jochen
J
Ditterich
The Fuster Laboratory of Cognitive Neuroscience, Department of Psychiatry and Biobehavioral Sciences, Department of Neurobiology, Semel Institute for Neuroscience and Human Behavior, Brain Research Institute, David Geffen School of Medicine at University of California, Los Angeles, 635 Charles Young Drive, Box 957332, Los Angeles, CA 90095, USA. Electronic address: mbasso@mednet.ucla.edu.
Michele A
MA
Basso
D000368:Aged; D003657:Decision Making; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000503:physiopathology / Q000523:psychology*; D010465:Perception; D011930:Reaction Time; D035501:Uncertainty
Glass patterns; basal ganglia; bias; cognition; decision-making; drift-diffusion model; expectancy; implicit learning; memory; perception