26 Feb Cooling Specific Brain Region During Surgery Protects Speech Function
MedicalResearch.com Interview with:
Dr. Michael Long
Michael A. Long, PhD
New York University School of Medicine
Assistant Professor New York Stem Cell Foundation
Robertson Neuroscience Investigator
Medical Research: What is the background for this study?
Response: Speech is, of course, central to our everyday lives, and it is perhaps the most thoroughly studied human behavior. That said, many aspects of how our brain produces speech are still poorly understood. Human brains are extremely complex, and many of the tools that are available to understand the function of the brain are quite limited. Although we have a good idea of the brain regions involved in producing speech, our understanding of the roles that each area plays to enable us to produce words is much less clear.
Medical Research: How did you become interested in this problem?
Response: I am a basic researcher focusing on the mechanisms that enable the brain to produce complex behaviors. We primarily study the songbird brain, which contains several clearly defined areas that are dedicated to producing the song. Through careful study, many research groups have discovered how these areas are working together to produce the song. I realized that this kind of perspective may be useful to further our understanding of human speech production.
Medical Research: How did you translate the findings from the songbird brain to the human brain?
Response: Many years ago, when I was a postdoc with Michalel Fee at MIT, I used a small head-mounted cooling device to selectively lower the temperature of specific brain regions in the songbird by a few degrees. To our surprise and delight, the cooling of a specific brain area – called HVC – resulted in a slowing of the tempo of that song. From this finding, we realized that HVC was a key timing center for singing, and by cooling that ‘clock’, the song that was produced happened more slowly. When I established my own lab at NYU, I reached out Dr. Matthew Howard’s Neurosurgery group at the University of Iowa because of his impressive history of making fundamental discoveries about human brain function. There I met Dr. Jeremy Greenlee, and we discussed using a cooling approach for understanding human speech. Since 2011, we worked with 22 patients that were undergoing neurosurgery for either epilepsy or tumor removal. Patients were asked to recite simple lists of words, like the days of the week, while a device with a footprint about the size of a quarter would cool different places along the surface of the brain.
Medical Research: What was your main finding?
Response: While some of the cooling locations did not result in any behavioral change, we found that affecting other portions of the brain could transiently alter speaking behavior. The amazing part is that the effects were dependent on the location of the cooling probe. In one area, speech became less intelligible, affecting mainly the quality of the words. In another area, however, the timing was strongly affected. Like our birds, patients sometime spoke in ‘slow motion’. This clearly defined change in behavior has helped us to shed light on the distinct roles that these areas play to enable us to speak.
Medical Research: What should clinicians and patients take away from your report?
Dr. Long: In addition to furthering our understanding of speech production, we now have developed cooling as a safe and effective way of identifying important speech regions so that surgeons can avoid damage to these areas during their procedures. This mapping process is safer than presently established protocols, which involve searching for speech areas using electrical current administered to specific parts of the brain.
Medical Research: What recommendations do you have for future research as a result of this study?
Dr. Long: Because our study was limited to understanding the production of a simple vocal task, we have just scratched the surface of the potential that focal cooling has in understanding brain function. This method can be used to address a wide range of questions concerning the mechanisms underlying behavior and the processes that enable us to perceive the world.
Citation:
Long, M. A., et al. (2016). Functional Segregation of Cortical Regions Underlying Speech Timing and Articulation. Neuron 89: 1–7. DOI: 10.1016/j.neuron.2016.01.032 [Abstract]
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Michael A. Long, PhD (2016). Cooling Specific Brain Region During Brain Surgery Protects Speech Function
Last Updated on February 26, 2016 by Marie Benz MD FAAD