Diffusion heterogeneity and anisotropy in rat hippocampus.
Mazel T, Simonova Z, Sykova E
Department of Neuroscience, 2nd Medical Faculty, Charles University, Prague,
Czech Republic.
We provide evidence for anisotropic diffusion in rat corpus callosum
and hippocampus. The preferential diffusion pathway in corpus callosum
is along the myelinated axon fibres; in the hippocampus diffusion is easier
along the transversal axis (x) than along the sagittal (y) or vertical
(z) axes. In all areas studied, i.e. in the cortex, corpus callosum and
hippocampus, the mean ECS volume fraction alpha (alpha = ECS volume/total
tissue volume) ranged between 0.20 and 0.22 and mean non-specific uptake
k' was between 4.0 and 5.9 x 10(-3) s-1. Diffusional anisotropy in the
hippocampus may be of importance for extrasynaptic transmission and in
the 'cross-talk' between synapses.
