Neural encoding of task-dependent errors during adaptive learning

Chang-Hao Kao,Joseph W Kable,Sangil Lee,Joshua I Gold

doi:10.7554/elife.58809

Abstract

Effective learning requires using errors in a task-dependent manner, for example adjusting to errors that result from unpredicted environmental changes but ignoring errors that result from environmental stochasticity. Where and how the brain represents errors in a task-dependent manner and uses them to guide behavior are not well understood. We imaged the brains of human participants performing a predictive-inference task with two conditions that had different sources of errors. Their performance was sensitive to this difference, including more choice switches after fundamental changes versus stochastic fluctuations in reward contingencies. Using multi-voxel pattern classification, we identified task-dependent representations of error magnitude and past errors in posterior parietal cortex. These representations were distinct from representations of the resulting behavioral adjustments in dorsomedial frontal, anterior cingulate, and orbitofrontal cortex. The results provide new insights into how the human brain represents errors in a task-dependent manner and guides subsequent adaptive behavior.

Highlights

Errors often drive adaptive adjustments in beliefs that inform behaviors that maximize positive outcomes and minimize negative ones (Sutton and Barto, 1998)
Several studies focused on variables derived from normative models that describe the degree to which individuals should dynamically adjust their beliefs in response to error feedback under different task conditions, including the probability that a fundamental change in the environment just occurred and the reducible uncertainty associated with estimates of environmental features
Correlates of these variables have been identified in dorsomedial frontal (DMFC) and dorsolateral prefrontal (DLPFC) cortex and medial and lateral posterior parietal cortex (PPC) (Behrens et al, 2007; McGuire et al, 2014; Nassar et al, 2019a)

Summary

Introduction

Errors often drive adaptive adjustments in beliefs that inform behaviors that maximize positive outcomes and minimize negative ones (Sutton and Barto, 1998). Several studies focused on variables derived from normative models that describe the degree to which individuals should dynamically adjust their beliefs in response to error feedback under different task conditions, including the probability that a fundamental change in the environment just occurred (change-point probability, or CPP, which is a form of surprise) and the reducible uncertainty associated with estimates of environmental features (relative uncertainty, or RU) Correlates of these variables have been identified in dorsomedial frontal (DMFC) and dorsolateral prefrontal (DLPFC) cortex and medial and lateral posterior parietal cortex (PPC) (Behrens et al, 2007; McGuire et al, 2014; Nassar et al, 2019a).

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