Musical Hallucinations

Musical Hallucinations
A woman with an "iPod in her head" has helped scientists at Newcastle University and University College London identify the areas of the brain that are affected when patients experience a rare condition called musical hallucinations.

What exactly are musical hallucinations?
Hallucinations are false percepts in the waking state that are not consequences of stimuli in the external environment, and can involve any sensory modality. Musical hallucinations (MH) are a type of auditory hallucination characterized by perception of musical sounds in the absence of any external source of music. Their content is often familiar and can be instrumental, vocal or both. While hallucinations of music can occasionally result from focal brain lesions and psychiatric disorders  the most common cause is hearing loss in the absence of other pathology.

During normal perception of music what we actually ‘hear’ is a complex interplay of the sound entering the ear and our brain’s interpretations and predictions. Normally the strength and quality of the input from the ear is so high that it dominates what we actually perceive, however the brain fills in the gaps when the ears do not provide enough input.

“With hearing loss,  the signal from the ear becomes weak and noisy, like a poorly-tuned radio. The brain’s predictive mechanisms therefore have to work very hard to make sense of what we are hearing. What we have found is that these processes sometimes end up running away with themselves to cause hallucinations,” said author Dr William Sedley also of Newcastle University.

Dr Kumar added: “This also explains why listening to an external piece of music suppresses hallucinations. When external music is playing the signal entering the brain is much stronger and more reliable, which constrains the aberrant communication going on in the brain areas during hallucinations.”
This new understanding of musical hallucinations may provide better treatment in the future for this condition.

Source:
http://www.ncl.ac.uk/press.office/press.release/item/the-ipod-in-the-head-how-the-brain-processes-musical-hallucinations
Reference:
http://www.sciencedirect.com/science/article/pii/S0010945213003080
Image via imgur