Avaliação da atividade eletroencefalográfica e da ativação BOLD em paradigmas auditivos Oddball

Abstract

This study investigates the relationship between neuronal activity observed via electro encephalography (EEG) and brain region activations recorded using functional magnetic resonance imaging (fMRI) data during the performance of an auditory oddball cognitive paradigm. The objective was to analyze whether event-related potentials, particularly the P300 component obtained via EEG, show a qualitative correspondence with the hemodynamic activation patterns measured by the BOLD signal in fMRI. Public data from the OpenfMRI repository (dataset ds000116) were used, comprising simultaneous EEG and fMRI recordings from 15 participants. The EEG data were preprocessed using the MNE-Python library, including digital filtering, removal of physiological artifacts via Independent Component Analysis (ICA), and extraction of event-related potentials. The P300 component was analyzed for amplitude, latency, and topographic distribution. The fMRI data were preprocessed using the fMRIPrep pipeline and analyzed using statistical modeling based on the General Linear Model (GLM) in FSL software, allowing for the estimation of BOLD activation maps associated with the target and standard conditions. The results showed the presence of the P300 component with maximum amplitude in the centro-parietal regions of the scalp and a mean latency of approximately 386 ms. In the fMRI data, significant activation was observed in the parietal, temporal, and frontal lobes, as well as the thalamus, primarily in the target condition.The qualitative compa rison between the modalities revealed macroscopic spatial correspondence between the topography of the P300 and the regions of BOLD activation. These findings reinforce the complementarity between EEG and fMRI and suggest that, with technological advances and a better understanding of the neural mechanisms involved in stimulus processing the P300 may in the future establish itself as an accessible biomarker for the investigation of cognitive processes.