title: Working memory load-dependent spatio-temporal activity of single-trial P3 response detected with an adaptive wavelet denoiser.
abstract: Working memory (WM) refers to the holding and manipulation of information during cognitive tasks. Its underlying neural mechanisms have been explored through both functional magnetic resonance imaging (fMRI) and electroencephalography (EEG). Trial-by-trial coupling of simultaneously collected EEG and fMRI signals has become an important and promising approach to study the spatio-temporal dynamics of such cognitive processes. Previous studies have demonstrated a modulation effect of the WM load on both the BOLD response in certain brain areas and the amplitude of P3. However, much remains to be explored regarding the WM load-dependent relationship between the amplitude of ERP components and cortical activities, and the low signal-to-noise ratio (SNR) of the EEG signal still poses a challenge to performing single-trial analyses. In this paper, we investigated the spatio-temporal activities of P3 during an n-back verbal WM task by introducing an adaptive wavelet denoiser into the extraction of single-trial P3 features and using general linear model (GLM) to integrate simultaneously collected EEG and fMRI data. Our results replicated the modulation effect of the WM load on the P3 amplitude. Additionally, the activation of single-trial P3 amplitudes was detected in multiple brain regions, including the insula, the cuneus, the lingual gyrus (LG), and the middle occipital gyrus (MOG). Moreover, we found significant correlations between P3 features and behavioral performance. These findings suggest that the single-trial integration of simultaneous EEG and fMRI signals may provide new insights into classical cognitive functions.
authors.affiliation: College of Information Science and Technology, Beijing Normal University, Beijing 100875, China; Department of Computer Science, University of Texas at Dallas, Richardson, TX, USA.
authors.forename: Qiushi
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: College of Information Science and Technology, Beijing Normal University, Beijing 100875, China.
authors.forename: Xueqian
authors.initials: X
authors.lastname: Yang
authors.affiliation: College of Information Science and Technology, Beijing Normal University, Beijing 100875, China; State Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University, Beijing 100875, China.
authors.forename: Li
authors.initials: L
authors.lastname: Yao
authors.affiliation: College of Information Science and Technology, Beijing Normal University, Beijing 100875, China. Electronic address: zhaoxj86@hotmail.com.
authors.forename: Xiaojie
authors.initials: X
authors.lastname: Zhao
mesh_terms: D000328:Adult; D001921:Brain / Q000502:physiology*; D001931:Brain Mapping; D004569:Electroencephalography; D018913:Event-Related Potentials, P300; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology*; D059629:Signal-To-Noise Ratio; D058067:Wavelet Analysis; D055815:Young Adult
keywords: EEG–fMRI; adaptive wavelet denoiser; load-dependent; single-trial; working memory