Direct magnetic resonance detection of neuronal electrical activity.
Present noninvasive neuroimaging methods measure neuronal activity indirectly, via either cerebrovascular changes or extracranial measurements of electrical/magnetic signals. Recent studies have shown evidence that MRI may be used to directly and noninvasively map electrical activity associated with human brain activation, but results are inconclusive. Here, we show that MRI can detect cortical electrical activity directly. We use organotypic rat-brain cultures in vitro that are spontaneously active in the absence of a cerebrovascular system. Single-voxel magnetic resonance (MR) measurements obtained at 7 T were highly correlated with multisite extracellular local field potential recordings of the same cultures before and after blockade of neuronal activity with tetrodotoxin. Similarly, for MR images obtained at 3 T, the MR signal changed solely in voxels containing the culture, thus allowing the spatial localization of the active neuronal tissue.
Petridou
Natalia
N
Section on Functional Imaging Methods, Laboratory of Brain and Cognition, Laboratory of Systems Neuroscience, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892, USA.
Plenz
Dietmar
D
Silva
Afonso C
AC
Loew
Murray
M
Bodurka
Jerzy
J
Bandettini
Peter A
PA
D000818:Animals; D004569:Electroencephalography; D004594:Electrophysiology; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009474:Neurons / Q000502:physiology*; D051381:Rats; D046509:Tissue Culture Techniques