Musical hallucinations make brain a jukebox
By CARL ZIMMER THE NEW YORK TIMES
Seven years ago, Reginald King was lying in a hospital bed recovering from bypass surgery when he first heard the music. It began with a pop tune, and others followed. King heard everything from cabaret songs to Christmas carols. "I asked the nurses if they could her the music, and they said no," said King, a retired sales manager in Cardiff, Wales. "I got so frustrated," he said. "They didn't know what I was talking about and said it must be something wrong with my head. And it's been like that ever since." Each day, the music returns. "They're all songs I've heard during my lifetime," said King, 83. "One would come on, and then it would run into another one, and that's how it goes on in my head. It's driving me bonkers, to be quite honest." Last year, King was referred to Dr. Victor Aziz, a psychiatrist and St. Cadoc's Hospital in Wales. Aziz explained to him that there was a name for his experience: musical hallucinations. Aziz belongs to a small circle of psychiatrists and neurologists who are investigating this condition. They suspect that the hallucinations experienced by King and others are a result of malfunctioning brain networks that normally allow us to perceive music. And based on his studies of the hallucinations, he suspects that in the next few decades, they will be far more common. In the July issue of the journal Psychopathology, Aziz and his colleague Dr. Nick Warner Wales, write about the largest case-series ever published for musical hallucinations. Aziz believes that people tend to hear songs they have heard repeatedly or that are emotionally significant to them. His study results support recent work by neuroscientists indicating that our brains use special networks of neurons to perceive music. When sounds first enter the brain, they activate a region near the ears called the primary auditory cortex that starts processing sounds at their most basic level. The auditory cortex then passes on signals of its own to other regions, which can recognize more complex features of music, like rhythm, key changes and melody. Neurocientists have been able to identify some of these regions with brain scans. Dr. Tim Griffiths, a neurologist at the University of Newcastel Upon Tyne in England, performed brain-scan studies on six elderly patients who developed musical hallucinations after becoming partly deaf. Griffiths discovered a network of regions in the brain that became more active as the hallucinations became more intense. These music-processing regions may be continually looking for signals in the brain that they can interpret, Griffiths suggested. When no sound is coming from the ears, the brain may still generate occasional, random impulses that the music processing regions interpret as sound. They then try to match these impulses to memories of music, turning a few notes into a familiar melody. It is also possible for people who are not deaf to experience musical hallucinations. Epileptic seizures, certain medications and Lyme disease are a few of the factors that may set them off.
|