Measuring diffusion parameters in the brain: comparing the real-time iontophoretic method and diffusion-weighted magnetic resonance.
The extracellular space (ECS) diffusion parameters influence the movement of ions, neuroactive substances, hormones and metabolites in the nervous tissue. They also affect extrasynaptic transmission, a mode of signal transmission dependent solely on diffusion. This review compares in detail two methods for studying diffusion in the brain: the real-time iontophoretic tetramethylammonium method for ECS volume fraction and tortuosity measurements and diffusion weighted-magnetic resonance imaging for measuring the apparent diffusion coefficient of water. The results obtained using both methods under physiological conditions (post-natal development, ageing) or in pathologies (brain injury, ischaemia) and their similarities and differences are discussed.
Vorisek
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I
Department of Neuroscience, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, Charles University, Prague, Czech Republic.
Sykova
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D000818:Animals; D001921:Brain / Q000502:physiology*; D006801:Humans; D007478:Iontophoresis; D008279:Magnetic Resonance Imaging / Q000379:methods*