Given her deafness, the auditory part of the brain, deprived of its usual input, had started to generate a spontaneous activity of its own, and this took the form of musical hallucinations, mostly musical memories from her earlier life. The brain needed to stay incessantly active, and if it was not getting its usual stimulation..., it would create its own stimulation in the form of hallucinations.
Oliver Sacks, Musicophilia: Tales of Music and the Brain
cognitive-neuroscience, hallucinations, music, musical-hallucinations, neuroscience, psychology, science