In Musicophilia's tales of music and the brain, specifically page 146 of my 2008 paperback, Oliver Sacks describes:
...recent work demonstrating that there are massive efferent connections (the olivocochlear bundles) going from the brain to the cochlea and thence to the outer hair cells. The outer hair cells serve, among other things, to calibrate or “tune” the inner hair cells, and they have an exclusively efferent nerve supply; they do not transmit nerve impulses to the brain, they get orders from the brain. Thus one has to see the brain and ear as forming a single functioning system, a two-way system, with the ability not only to modify the representation of sounds in the cortex but to modulate the output of the cochlea itself. The power of attention – to pick out a tiny but significant sound in our environment, to home in on a single soft voice in the ambient din of a crowded restaurant – is very remarkable and seems to depend on this ability to modulate cochlear function...
It made me wonder if the agitations described by Dan might be part of this two-way system, and if so; might this be a form of feedback?