...Both are theorized to be due to decreased inhibition in the visual cortex in response to decreased input (like turning up the gain on a CCD)....
This kind of makes sense, considering the aforementioned symptoms are frequently accompanied by tinnitus.
I found this tidbit about tinnitus, which seems to relate to the visual symptoms we're discussing about:
Studies by researchers at the
University of Western Australia suggest that
tinnitus is caused by increased neural activity in the auditory brainstem where the brain processes sounds, causing some auditory nerve cells to become overexcited. The basis of this theory is that most people with tinnitus also have
hearing loss[8] and the frequencies they cannot hear link to the subjective frequencies of their tinnitus.
[9] Models of hearing loss and the brain support the idea that a
homeostatic response of central
dorsal cochlear nucleus neurons could result in them being hyperactive in a compensation process to the loss of hearing input.
[10] This in turn is related to
changes in the genes involved in regulating the activity of those nerve cells. This proposed mechanism suggests possible treatments for the condition, involving the normalization or suppression of overactive neural activity through electrical or chemical means.
(bold and underlined are my own highlights)
In summary, like with palinopsia and visual snow, one theory with tinnitus seems to suggest overactive firing/reduced inhibition. I wonder if there is a common link here, some underlying cause that might contribute to this?
Also, I am curious about the outlook, if this usually permanent once it takes hold, or if it can be seen as possibly transitory and circumstantial, like depression?
