Multivariate Bayesian decoding of single-trial event-related fMRI responses for memory retrieval of voluntary actions

Dongha Lee, Sungjae Yun, Changwon Jang, Hae-Jeong Park, Suliann Ben Hamed
2017 PLoS ONE  
This study proposes a method for classifying event-related fMRI responses in a specialized setting of many known but few unknown stimuli presented in a rapid event-related design. Compared to block design fMRI signals, classification of the response to a single or a few stimulus trial(s) is not a trivial problem due to contamination by preceding events as well as the low signal-to-noise ratio. To overcome such problems, we proposed a single trial-based classification method of rapid
more » ... d fMRI signals utilizing sparse multivariate Bayesian decoding of spatio-temporal fMRI responses. We applied the proposed method to classification of memory retrieval processes for two different classes of episodic memories: a voluntarily conducted experience and a passive experience induced by watching a video of others' actions. A cross-validation showed higher classification performance of the proposed method compared to that of a support vector machine or of a classifier based on the general linear model. Evaluation of classification performances for one, two, and three stimuli from the same class and a correlation analysis between classification accuracy and target stimulus positions among trials suggest that presenting two target stimuli at longer interstimulus intervals is optimal in the design of classification experiments to identify the target stimuli. The proposed method for decoding subject-specific memory retrieval of voluntary behavior using fMRI would be useful in forensic applications in a natural environment, where many known trials can be extracted from a simulation of everyday tasks and few target stimuli from a crime scene. OPEN ACCESS Citation: Lee D, Yun S, Jang C, Park H-J (2017) Multivariate Bayesian decoding of single-trial event-related fMRI responses for memory retrieval of voluntary actions. PLoS ONE 12(8): e0182657.
doi:10.1371/journal.pone.0182657 pmid:28777830 pmcid:PMC5544208 fatcat:bdsvbkrthnhcfa2oztgkrkomca