Brain Topography

, Volume 21, Issue 2, pp 112–127

Spatial Correspondence Between Functional MRI (fMRI) Activations and Cortical Current Density Maps of Event-Related Potentials (ERP): A Study with Four Tasks

Authors

    • Science Direction UnitFondazione IRCCS Istituto Neurologico “Carlo Besta”
    • Neuroradiology DepartmentFondazione IRCCS Istituto Neurologico “Carlo Besta”
  • Cristina Rosazza
    • Science Direction UnitFondazione IRCCS Istituto Neurologico “Carlo Besta”
    • Neuroradiology DepartmentFondazione IRCCS Istituto Neurologico “Carlo Besta”
    • Institut des Sciences CognitivesCNRS
  • Ileana Zucca
    • Science Direction UnitFondazione IRCCS Istituto Neurologico “Carlo Besta”
    • Neuroradiology DepartmentFondazione IRCCS Istituto Neurologico “Carlo Besta”
  • Ludovico D’Incerti
    • Neuroradiology DepartmentFondazione IRCCS Istituto Neurologico “Carlo Besta”
  • Vidmer Scaioli
    • Neurophysiopathology DepartmentFondazione IRCCS Istituto Neurologico “Carlo Besta”
  • Maria Grazia Bruzzone
    • Neuroradiology DepartmentFondazione IRCCS Istituto Neurologico “Carlo Besta”
Original Paper

DOI: 10.1007/s10548-008-0064-3

Cite this article as:
Minati, L., Rosazza, C., Zucca, I. et al. Brain Topogr (2008) 21: 112. doi:10.1007/s10548-008-0064-3

Abstract

We investigated the spatial correspondence between functional MRI (fMRI) activations and cortical current density maps of event-related potentials (ERPs) reconstructed without fMRI priors. The presence of a significant spatial correspondence is a prerequisite for direct integration of the two modalities, enabling to combine the high spatial resolution of fMRI with the high temporal resolution of ERPs. Four separate tasks were employed: visual stimulation with a pattern-reversal chequerboard, recognition of images of nameable objects, recognition of written words, and auditory stimulation with a piano note. ERPs were acquired with 19 recording channels, and source localisation was performed using a realistic head model, a standard cortical mesh and the multiple sparse priors method. Spatial correspondence was evaluated at group level over 10 subjects, by means of a voxel-by-voxel test and a test on the distribution of local maxima. Although not complete, it was significant for the visual stimulation task, image and word recognition tasks (P < 0.001 for both types of test), but not for the auditory stimulation task. These findings indicate that partial but significant spatial correspondence between the two modalities can be found even with a small number of channels, for three of the four tasks employed. Absence of correspondence for the auditory stimulation task was caused by the unfavourable situation of the activated cortex being perpendicular to the overlying scalp, whose consequences were exacerbated by the small number of channels. The present study corroborates existing literature in this field, and may be of particular relevance to those interested in combining fMRI with ERPs acquired with the standard 10-20 system.

Keywords

Event-related potentialsFunctional MRISpatial correspondenceVisual stimulationImage recognitionWord recognitionAuditory stimulation

Copyright information

© Springer Science+Business Media, LLC 2008