# Decoding P300 as a shared neural mechanism for oddball target detection and working memory updating

## TL;DR

This study shows that the P300 brain signal is a shared mechanism for both detecting oddball targets and updating working memory.

## Contribution

The study demonstrates cross-task decoding of P300 using EEG MVPA, revealing shared neural mechanisms between oddball and working memory tasks.

## Key findings

- Classifiers trained on EEG patterns from the oddball task decoded those from the n-back task and vice versa.
- The shared P300 effect was localized in the parietal/occipital region during the P300 time window.
- The P300's shared role remains robust even after accounting for working memory load.

## Abstract

The P300 is a well-established neurophysiological component that has been extensively investigated within the oddball paradigm and is commonly interpreted as reflecting context or working memory (WM) updating. This interpretation implies that the P300 elicited by oddball target detection shares neural mechanisms with the P300 elicited by WM. To test this hypothesis, we applied multivariate pattern analysis to perform cross-task decoding between EEG patterns during an oddball task and an n-back task, a classical WM paradigm. We found that classifiers trained on EEG patterns from the oddball task successfully decoded those from the n-back task, and vice versa, with the effect concentrated in the parietal/occipital region within the P300 time window. These findings suggest that the P300 serves as a shared neural mechanism for oddball target detection and WM updating, supporting the WM updating account of the P300 from the perspective of neural representation.

•EEG MVPA enables cross-task decoding between oddball and n-back tasks•P300 serves as a shared neural mechanism for oddball target detection and WM updating•Shared P300 effect remains robust after controlling for WM load•Cross-task MVPA supports the context updating theory of the P300

EEG MVPA enables cross-task decoding between oddball and n-back tasks

P300 serves as a shared neural mechanism for oddball target detection and WM updating

Shared P300 effect remains robust after controlling for WM load

Cross-task MVPA supports the context updating theory of the P300

Systems neuroscience; Cognitive neuroscience; Biocomputational method