How Music and Language Activates Brain

According to UTHealth Houston research, distinct, albeit surrounding, portions of the brain are involved while processing music and language, with unique sub-regions engaged for basic melodies vs complicated melodies, and for simple versus complex phrases.
The work was just published in iScience by co-first authors Meredith McCarty, Ph.D. candidate in the Vivian L. Smith Department of Neurosurgery at McGovern Medical School at UTHealth Houston, and Elliot Murphy, Ph.D., postdoctoral research fellow in the department. Senior author was Nitin Tandon, MD, professor and acting chair of the department of the medical school.

The opportunity presented during an awake craniotomy on a young musician with a tumor in the brain regions involved in language and music was used by the study team. To map his musical abilities, the patient heard music and played a mini-keyboard piano, as well as heard and repeated statements and descriptions of things, which he then labeled. Musical sequences were either melodic or not and varied in complexity, whilst auditory recordings of sentences varied in grammatical complexity.

The location and features of brain activity during music and language were mapped out using direct brain recordings with electrodes inserted on the brain surface. Small currents were transmitted through the brain to identify areas important for language and music perception and production.

“This allowed us not just to obtain novel insights into the neurobiology of music in the brain, but to enable us to protect these functions while performing a safe, maximal resection of the tumor,” said Tandon, the Nancy, Clive and Pierce Runnels Distinguished Chair in Neuroscience of the Vivian L. Smith Center for Neurologic Research and the BCMS Distinguished Professor in Neurological Disorders and Neurosurgery with McGovern Medical School and a member of the Texas Institute for Restorative Neurotechnologies (TIRN) at UTHealth Houston.

“If we look purely at basic brain activation profiles for music and language, they often look pretty similar, but that’s not the full story,” said McCarty, who is also a graduate research assistant at The University of Texas MD Anderson Cancer Center UTHealth Houston Graduate School of Biomedical Sciences and a member of TIRN. “Once we look closer at how they assemble small parts into larger structures, some striking neural differences can be detected.”

Language and music both involve the productive integration of basic structural pieces. Researchers wanted to see if brain regions sensitive to linguistic and musical structure are co-localized, or share physical space.

“The unparalleled, high resolution of intracranial electrodes allows us to ask the kinds of questions about music and language processing that cognitive scientists have long awaited answers for, but were unable to address with traditional neuroimaging methods,” said Murphy, a member of TIRN. “This work also truly highlights the generosity of patients who work closely with researchers during their stay at the hospital.”

Overall, they revealed shared temporal lobe activity for music and language, but when they examined melodic and grammatical complexity aspects, they discovered different temporal lobe locations to be activated. As a result, music and language activation are similar at the fundamental level; yet, when the researchers compared basic melodies vs. sophisticated melodies, or simple sentences vs. complicated sentences, various locations revealed varied sensitivities.

Cortical stimulation mapping of the posterior superior temporal gyrus (pSTG) specifically impaired music perception and production, as well as speech production. For language and music, the pSTG and posterior middle temporal gyrus (pMTG) are active. While musical complexity affected pMTG activity, grammatical complexity modulated pSTG activity.

Tandon performed a mid-temporal lobe tumor resection at Memorial Hermann-Texas Medical Center. The patient’s musical and language function was totally retained at his four-month follow-up, with no evidence of deterioration.

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