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Inability to directly detect magnetic field changes associated with neuronal activity
Author(s) -
Parkes Laura M.,
de Lange Floris P.,
Fries Pascal,
Toni Ivan,
Norris David G.
Publication year - 2007
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.21129
Subject(s) - replicate , neuroscience , signal (programming language) , neuroimaging , sensitivity (control systems) , computer science , brain activity and meditation , electroencephalography , functional magnetic resonance imaging , premovement neuronal activity , psychology , pattern recognition (psychology) , nuclear magnetic resonance , artificial intelligence , physics , mathematics , engineering , statistics , electronic engineering , programming language
The ability to directly detect neuronal magnetic fields by MRI would help investigators achieve the “holy grail” of neuroimaging, namely both high spatial and temporal resolution. Both positive and negative findings have been reported in the literature, with no clear consensus as to the feasibility of direct detection. The aim of this study was to replicate one of the most promising published in vivo results. A second aim was to investigate the use of steady‐state visual evoked potentials (ssVEPs), which give a large evoked response and offer a well‐controlled approach because the frequency of the neuronal response can be dictated by the experimenter. For both studies we used a general linear model (GLM) that included regressors for both the expected blood oxygen level‐dependent (BOLD) signal and the magnetic source (MS) signal. The results showed no activity that could be attributed to the neuromagnetic signals in either study, and no frequency component corresponding to the frequency of the ssVEPs. This study demonstrates that for the particular stimuli and hardware used, the sensitivity of the magnitude MRI signal to detect evoked neuronal currents is too low to be of practical use. Magn Reson Med 57:411–416, 2007. © 2007 Wiley‐Liss, Inc.