Parkinson’s Disease is a neurological condition associated with slowness of movement, tremor, muscle rigidity, and instability of gait. These symptoms stem from the fact that Parkinson’s entails the degeneration of dopaminergic neurons in parts of the deep brain structures called the basal ganglia, which are important for movement. This causes depletion of dopamine in the brain. Parkinson’s cannot be cured, but there are options for treatment and management of symptoms. Typically, Parkinson’s is treated pharmacologically with drugs that increase dopamine levels in the brain. Sometimes however, the drugs become less effective over time and other types of treatments must be pursued. One such approach used for treatment of severe, drug-resistant cases of Parkinson’s is deep-brain stimulation (DBS), in which a device is surgically implanted into the brain. This device electrically stimulates the basal ganglia and provides relief from movement disorders. Here is a striking video of an individual with Parkinson’s demonstrating the effects of his DBS device on his movement disorder.
The portion of the surgery for device implantation where the patient is awake but only locally anesthetized, provides researchers with a unique opportunity to conduct studies on brain function that they could normally not do. Typically, the electrical activity of the brain is investigated with electrodes placed on the scalp, but based on this data, it is difficult to accurately pinpoint the source of the activity. During brain surgery this is not a problem, as researchers are able to record activity directly from the areas they are interested in.
Recently, researchers reported preliminary findings from measurements conducted during neurosurgical implantation of DBS devices. The subjects were seven patients who listened to three different classical music clips while researchers recorded electrical activity from neurons in the thalamic as well as subthalamic nuclei, which are important for movement. According to the results, melodic classical music decreased neuronal firing in thalamic and subthalamic nuclei, compared to music with distinct rhythm. This means that the music directly modulated the firing patterns of neurons related to movement, with more rhythmic music increasing the activity of these neurons.
The preliminary results of the current study are interesting and after rigorous peer-review and journal publication, will make an important addition to current understanding about the deep connection between music and movement already reported by several other research groups. According to previous research, perceiving and producing music both involve the interaction of motor and auditory systems in the brain. The current study adds to these findings by providing more support for the notion that rhythm might be the key aspect of activating movement-related areas of the brain with music. The current study also helps us better understand why music therapy, and more specifically something called rhythmic auditory stimulation (RAS), has been found to be successful in treatment of movement disabilities related to Parkinson’s. Future research into music and movement will likely uncover more fascinating aspects about why music moves us, and how this connection can be most effectively utilized in treatment of severe conditions such as Parkinson’s.
Written by ketki Karanam
Zatorre, R. J., Chen, J. L., & Penhune, V. B. (2007). When the brain plays music: auditory–motor interactions in music perception and production. Nat Rev Neurosci, 8(7), 547–558. doi:10.1038/nrn2152