Bill Beatty wrote a thought-provoking
essay showing the unity of sound, heat, and electromagnetic
radiation. Heat is a form of sound, of very high frequency and wide
bandwidth. This is acknowledged in the theory explaining
superconductivity, which treats heat and sound as being composed of
quantum pseudo-particles called phonons. Heimburg et. al. showed that neural impulses are primarily sound-like, accounting for their
low speed and because of their solitonic form their lack of energy
dissipation. The electrical effects associated with the impulses are
due to the thickening of the neural membrane during the pulse
increasing the separation between the charges on the inside and
outside of the membrane, resulting in a transient decrease in
capacitance which increases the voltage across the membrane.
Tree-like structures such as neurons have a rich spectrum of
mechanical resonances, largely due indirectly to the form of the
cytoskeleton, which determines the form and stiffness of the neuron.
Neural pulses also resonate with parts of the cytoskeleton and may
change its form, as the microtubules together with the layers of
ordered water surrounding them have non-linear ferroelectric and
topological quantum properties which are linked to discrete shape
changes of the microtubules which in turn affect the shape of axons,
dendrites and thus the neurons' mechanical resonances.