The Neural Computations In The Caudate Nucleus For Reward-Biased Perceptual Decision-Making

Loading...
Thumbnail Image
Degree type
Doctor of Philosophy (PhD)
Graduate group
Neuroscience
Discipline
Subject
caudate nucleus
computation
decision-making
drift-diffusion model
optimality
reward
Neuroscience and Neurobiology
Funder
Grant number
License
Copyright date
2020-02-07T20:19:00-08:00
Distributor
Related resources
Author
Fan, Yunshu
Contributor
Abstract

Decision-making is a complex process in which our brain has to combine different sources of information, such as noisy sensory evidence and expected reward, in appropriate ways to obtain the outcome that satisfies the decision-maker. Despite various studies on perceptual decision-making and value-based decision making, it is still unclear how the brain combines sensory and reward information to make a complex decision. A prime candidate for mediating this process is the basal ganglia pathway. This pathway is known to make separate contributions to perceptual decisions based on the interpretation of uncertain sensory evidence and value-based decisions that select among outcome options. To begin to investigate what computations are performed by the brain, particularly in the basal ganglia, we trained monkeys to perform a reward-biased visual motion direction discrimination task and performed single-unit extracellular recordings in the caudate nucleus, the input station in the basal ganglia. Fitting the monkeys’ behaviors to a drift-diffusion model, we found that the monkeys used a rational heuristic to combine sensory and reward information. This heuristic is suboptimal but leads to good-enough outcomes. We also found that the monkeys’ reward biases were sensitive to the changes in the reward functions from session to session. This adaptive adjustment could be a possible reason underlying the individual variability in their decision strategies. By recording in the caudate nucleus, we found that it is involved in both the decision-formation and evaluation: before the monkey started accumulating sensory evidence, the caudate neurons represented the reward context that could be used to form a reward bias; during decision-formation, some caudate neurons jointly represented sensory evidence and reward information, which could facilitate the combining of sensory and reward information appropriately. After a decision is made, caudate nucleus represented both decision confidence and reward expectation, two evaluation-related quantities that influence the monkeys’ subsequent decision behaviors.

Advisor
Long . Ding
Joshua I. Gold
Date of degree
2019-01-01
Date Range for Data Collection (Start Date)
Date Range for Data Collection (End Date)
Digital Object Identifier
Series name and number
Volume number
Issue number
Publisher
Publisher DOI
Journal Issue
Comments
Recommended citation