  This review addresses the acute need to acknowledge the mechanical
heterogeneity of brain matter and to accurately calibrate its local
viscoelastic material properties accordingly. Specifically, it is important to
compile the existing and disparate literature on attenuation power laws and
dispersion to make progress in wave physics of brain matter, a field of
research that has the potential to explain the mechanisms at play in diffuse
axonal injury and mild traumatic brain injury in general. Currently, viscous
effects in the brain are modelled using Prony-series, i.e., a sum of decaying
exponentials at different relaxation times. Here we collect and synthesise the
Prony-series coefficients appearing in the literature for twelve regions:
brainstem, basal ganglia, cerebellum, corona radiata, corpus callosum, cortex,
dentate gyrus, hippocampus, thalamus, grey matter, white matter, homogeneous
brain, and for eight different mammals: pig, rat, human, mouse, cow, sheep,
monkey and dog. Using this data, we compute the fractional-exponent attenuation
power laws for different tissues of the brain, the corresponding dispersion
laws resulting from causality, and the averaged Prony-series coefficients.
