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Coupling of neural activity and BOLD fMRI response: New insights by combination of fMRI and VEP experiments in transition from single events to continuous stimulation
Author(s) -
Janz C.,
Heinrich S.P.,
Kornmayer J.,
Bach M.,
Hennig J.
Publication year - 2001
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.1217
Subject(s) - functional magnetic resonance imaging , stimulus (psychology) , neuroscience , psychology , haemodynamic response , interstimulus interval , brain mapping , stimulation , cognitive psychology , medicine , heart rate , blood pressure , radiology
Functional magnetic resonance imaging (fMRI) measures the correlation between the fMRI response and stimulus properties. A linear relationship between neural activity and fMRI response is commonly assumed. However, the response to repetitive stimulation cannot be explained by a simple superposition of single‐event responses. This might be due to neural adaptation or the hemodynamic changes underlying the fMRI BOLD response. To assess the influence of adaptation, the BOLD responses and visual evoked potentials (VEPs) to identical stimuli were recorded. To achieve different adaptation levels, 2‐s stimulus epochs alternated with different interstimulus intervals (ISI = 0.0, 0.4, 0.8, 2.0, and 12 s) were presented. Neural adaptation during the checkerboard reversal paradigm used for fMRI measurements is demonstrated. Even if the measured VEP amplitude is used as the weighting function for a linear model, the measured BOLD fMRI signal time‐course is not adequately predicted. Magn Reson Med 46:482–486, 2001. © 2001 Wiley‐Liss, Inc.