A Brain Basis for Musical Hallucinations?

By Neuroskeptic | January 23, 2014 5:14 pm

Why do some people hear music that’s not there?

Musical hallucinations are most commonly found in people who have suffered hearing loss or deafness. But why they happen is unknown. In a new paper in Cortex, British neuroscientists Kumar et al claim to have found A brain basis for musical hallucinations

Using magnetoencephalography (MEG), the authors investigate brain activity in a patient, a 66 year old woman who had been hearing phantom ‘piano melodies’ for almost two years, after she had suddenly become partly deaf. She was an amateur keyboard player, and was able to write down the tunes she ‘heard': musicalhallucinationThe same melody – sometimes a real tune, sometimes ‘made up’ – would repeat for hours at a time, and it could get annoying. However, she had discovered that listening to certain pieces of real music provided temporary relief; the hallucinations would stop during the piece, and only restart after a certain lag-period of several seconds.

Kumar et al made use of this fact to compare brain activity when hallucinations were ‘on’ and ‘off’ – they recorded MEG data before and after playing 15 seconds of Bach, one of the hallucination-blocking composers. Immediately after each Bach burst, hallucinations were low, while 60 seconds later they had returned.

hallucinationsClever… however there’s a serious problem in this procedure: it can’t separate the effects of hallucinations from the effects of stopping listening to real music, nor from the expectation of future real music (the timing of which was predictable).

The obvious solution would have been to also include bursts of some music that didn’t block hallucinations, as a control condition. The patient herself reported that some music didn’t. This would dramatically increase the inferences one could draw from the data. Some MEG data from healthy control participants hearing the same music would also help to establish specificity. This limitation isn’t acknowledged.

Anyway, Kumar et al report increased gamma band activity in the left aSTG area, part of the auditory cortex. They say that

The area that shows higher activity during musical hallucination coincides with an area implicated in the normal perception of melody using fMRI.

However, strangely, the actual Bach music did not produce significant changes in activity in this area, or anywhere else in the brain. Only  imaginary music caused real brain waves; Kumar et al say that this has been seen in other studies and

It is not yet understood why phantom percepts are associated with much stronger gamma oscillations, as measured with MEG and electroencephalography (EEG), than those associated with external sensory stimulation; for review see Sedley & Cunningham, 2013 “Do cortical gamma oscillations promote or suppress perception?”

Some other changes in the beta frequency band were found in the motor cortex and posteromedial cortex/precuneus. Neither of these is thought of as a ‘music area’. To be honest, I don’t think these results shed much light on the phenomenon.

The second half of the paper is rather different, providing a theoretical overview of musical hallucination. This section could almost be a paper in itself. The authors argue that

Our hypothesis is that peripheral hearing loss reduces the signal-to-noise ratio of incoming auditory stimuli and the brain responds by decreasing sensory precision or post-synaptic gain…

A recurrent loop of communication is thus established which is no longer informed, or entrained, by precise bottom-up sensory prediction errors… it is constrained only by a need to preserve the internal consistency between hierarchical representations of music.

This reciprocal communication between an area in music perception and area/s involved in higher music cognition (motor cortex and precuneus) with no constraint from the sensory input gives rise to musical hallucinations.

ResearchBlogging.orgKumar S, Sedley W, Barnes GR, Teki S, Friston KJ, & Griffiths TD (2013). A brain basis for musical hallucinations. Cortex PMID: 24445167

CATEGORIZED UNDER: EEG, mental health, music, papers, select, Top Posts
  • Pingback: 24/01/2014 | Magapsine()

  • Bud Balentine

    No recent hearing loss. Hear 50’s R&R. Consciously play Beethoven et.al. to temporarily stop music or short musical phrases repeated endlessly. May return immediately or some hours later. On rare occasions an obscure name may be heard repeatedly. Ex: NFL referee’s name.

  • Pingback: Magapsine (S04-2014) | dronte.es()

  • Allyson Lyne

    As a violinist and professional musician, I would like to point out that there is a difference between hearing external music and generating an internal auditory track which one uses as a sort of “cam” or “master” to coordinate hands, ears, and brain while playing. Presumably there is a different brain activity involved, which seems pertinent to this study. It would be useful to compare self-generated or participatory internal audio activity with simple audition of external music, to see if perhaps the sort of listening music which cancels out the hallucinatory music is involving a higher degree of self-generated auditory participation.

    Or, to express it more simply, there is a difference between listening and hearing!

  • Daniel C Barker

    I have experienced something similar for years (when in silence with a slight white noise)` I hear what sounds like a radio station constantly on with random talking and music very faint from no particular direction.

    • Justan American

      Tell your dentist.Some peoples fillings can receive radio signals.
      This is not a joke, but a known fact.

      • http://blogs.discovermagazine.com/neuroskeptic/ Neuroskeptic

        It is a well-known idea but apparantly it’s not true. A pity, it would be awesome.

  • Barry Keate

    Many people who experience these sounds tend to have considerable anxiety about them. They don’t talk openly about them with others and may be afraid there is a mental health component to the sounds. They are worried they will be deemed mentally unstable or psychotic. This is not the case.

    Source: http://www.tinnitusformula.com/library/musical-ear-syndrome-and-tinnitus/

  • Vierotchka

    For several years, when I was a child, I heard absolutely glorious polyphonic symphonic music that went on and on all day. It has me enraptured and I absolutely loved it. I was sad when it finally went away. I never had any kind of hearing loss of deafness prior to hearing this music which was indescribably beautiful. It was as if I had stereo hearphones inside of my head. That music often was quite loud but never uncomfortably so.

  • http://blogs.discovermagazine.com Longmire

    The term musical hallucination discounts a vast platform of consciousness.

NEW ON DISCOVER
OPEN
CITIZEN SCIENCE
ADVERTISEMENT

Discover's Newsletter

Sign up to get the latest science news delivered weekly right to your inbox!

Neuroskeptic

No brain. No gain.

About Neuroskeptic

Neuroskeptic is a British neuroscientist who takes a skeptical look at his own field, and beyond. His blog offers a look at the latest developments in neuroscience, psychiatry and psychology through a critical lens.

ADVERTISEMENT

See More

@Neuro_Skeptic on Twitter

ADVERTISEMENT
Collapse bottom bar
+

Login to your Account

X
E-mail address:
Password:
Remember me
Forgot your password?
No problem. Click here to have it e-mailed to you.

Not Registered Yet?

Register now for FREE. Registration only takes a few minutes to complete. Register now »