Choice confidence, an individual's internal estimate of judgment accuracy, plays a critical role in adaptive behaviour, yet its neural representations during decision formation remain underexplored. Here, we recorded simultaneous EEG-fMRI while participants performed a direction discrimination task and rated their confidence on each trial. Using multivariate single-trial discriminant analysis of the EEG, we identified a stimulus-independent component encoding confidence, which appeared prior to subjects' choice and explicit confidence report, and was consistent with a confidence measure predicted by an accumulation-to-bound model of decision-making. Importantly, trial-to-trial variability in this electrophysiologically-derived confidence signal was uniquely associated with fMRI responses in the ventromedial prefrontal cortex (VMPFC), a region not typically associated with confidence for perceptual decisions. Furthermore, activity in the VMPFC was functionally coupled with regions of the frontal cortex linked to perceptual decision-making and metacognition. Our results suggest the VMPFC holds an early confidence representation arising from decision dynamics, preceding and potentially informing metacognitive evaluation.
The data and code required to reproduce the main and supplementary figures have been uploaded to Dryad. The full EEG-fMRI dataset will be freely available upon publication at: https://openneuro.org/datasets/ds001512.
Data from: Human VMPFC encodes early signatures of confidence in perceptual decisionsAvailable at Dryad Digital Repository under a CC0 Public Domain Dedication.
Simultaneous EEG-fMRI - Confidence in perceptual decisionsFreely available.
- Marios Philiastides
- Marios Philiastides
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Human subjects: The study was approved by the College of Science and Engineering Ethics Committee at the University of Glasgow (CSE01355) and informed consent, and consent to publish, was obtained from all participants.
- Tobias H Donner, University Medical Center Hamburg-Eppendorf, Germany
© 2018, Gherman & Philiastides
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.