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Diffusion‐weighted NMR imaging changes caused by electrical activation of the brain
Author(s) -
Prichard James W.,
Zhong Jianhui,
Petroff Ognen A. C.,
Gore John C.
Publication year - 1995
Publication title -
nmr in biomedicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.278
H-Index - 114
eISSN - 1099-1492
pISSN - 0952-3480
DOI - 10.1002/nbm.1940080709
Subject(s) - status epilepticus , effective diffusion coefficient , extracellular , cortical spreading depression , neuroscience , chemistry , neocortex , nuclear magnetic resonance , ischemia , biophysics , epilepsy , magnetic resonance imaging , medicine , biology , biochemistry , radiology , physics , migraine
The apparent diffusion coefficient of brain water was decreased by frontal cortical electroshock, usually but not always associated with brief epileptic afterdischarge detectable at the parietal cortex. Previous studies have shown that status epilepticus causes similar larger decreases, which are largely reversible by the termination of seizure discharge with pentobarbital. Cerebral blood flow is elevated in these conditions, and biochemical energy failure does not occur. The brain water diffusion coefficient also decreases in spreading depression, without depletion of energy stores. All of these findings may be due in part to the reduction of brain extracellular space caused by cell swelling, which occurs to some degree in all three conditions. However, major biological differences between brain activation and brain ischemia and new evidence for increased cytosolic viscosity in the latter both suggest that other mechanisms deserve further investigation. Use‐dependent motility of dendritic spines and other phenomena that may allow direct detection of neural activity by diffusion‐weighted NMR imaging are of special interest.