Elsevier

NeuroImage

Volume 16, Issue 1, May 2002, Pages 103-114
NeuroImage

Regular Article
Task-Related Changes in Cortical Synchronization Are Spatially Coincident with the Hemodynamic Response

https://doi.org/10.1006/nimg.2001.1050Get rights and content

Abstract

Using group functional Magnetic Resonance Imaging (fMRI) and group Magnetoencephalography (MEG) we studied two cognitive paradigms: A language task involving covert letter fluency and a visual task involving biological motion direction discrimination. The MEG data were analyzed using an adaptive beam-former technique known as Synthetic Aperture Magnetometry (SAM), which provides continuous 3-D images of cortical power changes. These images were spatially normalized and averaged across subjects to provide a group SAM image in the same template space as the group fMRI data. The results show that frequency-specific, task-related changes in cortical synchronization, detected using MEG, match those areas of the brain showing an evoked cortical hemodynamic response with fMRI. The majority of these changes were event-related desynchronizations (ERDs) in the 5–10 Hz and 15–25 Hz frequency ranges. Our study demonstrates how SAM, spatial normalization, and intersubject averaging enable group MEG studies to be performed. SAM analysis also allows the MEG experiment to have exactly the same task design as the corresponding fMRI experiment. This new analysis framework represents an important advance in the use of MEG as a cognitive neuroimaging technique and also allows mutual cross-validation with fMRI.

References (53)

  • W. Klimesch et al.

    Simultaneous desynchronization and synchronization of different alpha responses in the human electroencephalograph: A neglected paradox?

    Neurosci. Lett.

    (2000)
  • W. Klimesch et al.

    Episodic retrieval is reflected by a process specific increase in human electroencephalographic theta activity

    Neurosci. Lett.

    (2001)
  • C.M. Krause et al.

    Test-retest consistency of the event-related desynchronization/event-related synchronization of the 4–6, 6–8, 8–10, and 10–12 Hz frequency bands during a memory task

    Clin. Neurophysiol.

    (2001)
  • G.A. Orban et al.

    Human cortical regions involved in extracting depth from motion

    Neuron

    (1999)
  • G. Pfurtscheller et al.

    On the existence of different types of central beta rhythms below 30 Hz

    Electroencephalogr. Clin. Neurophysiol.

    (1997)
  • G. Pfurtscheller et al.

    Event-related EEG/MEG synchronization and desynchronization: Basic principles

    Clin. Neurophysiol.

    (1999)
  • S. Sunaert et al.

    Attention to speed of motion, speed discrimination, and task difficulty: An fMRI study

    Neuroimage

    (2000)
  • M. Taniguchi et al.

    Movement-related desynchronization of the cerebral cortex studied with spatially filtered magnetoencephalography

    Neuroimage

    (2000)
  • S.P. Ahlfors et al.

    Spatiotemporal activity of a cortical network for processing visual motion revealed by MEG and fMRI

    J. Neurophysiol.

    (1999)
  • G. Barnes et al.

    The spatial relationship between event-related changes in cortical synchrony and the haemodynamic response: An MEG-fMRI study

    Neuroimage

    (2001)
  • E. Bonda et al.

    Specific involvement of human parietal systems and the amygdala in the perception of biological motion

    J. Neurosci.

    (1996)
  • A.P. Burgess et al.

    Short duration power changes in the EEG during recognition memory for words and faces

    Psychophysiology

    (2000)
  • D. Chawla et al.

    Relating macroscopic measures of brain activity to fast, dynamic neuronal interactions

    Neural Comput.

    (2000)
  • D. Chawla et al.

    The relationship between synchronization among neuronal populations and their mean activity levels

    Neural Comput.

    (1999)
  • L. Cornette et al.

    Human brain regions involved in direction discrimination

    J. Neurophysiol.

    (1998)
  • D.W. Dickins et al.

    An fMRI study of stimulus equivalence

    Neuroreport

    (2001)
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