Division of labor between left and right brain hemispheres is a feature of vertebrate brains. The evolutionary advantage of dividing processing tasks is the ability to process different types of information at once, and to perform parallel tasks, like those involved in driving a car. Speech and melody are both processed in the left and right auditory cortex of the brain, respectively. However, it has been unclear how these brain areas carry out different functions.
Human studies have demonstrated that the left superior temporal gyrus mediates language processing and responds mainly to the rapidly-occurring components of spoken language. In contrast, the right superior temporal gyrus responds to information above the level of individual words like pitch and loudness. Studies of human language suggest the differences in signal processing in each hemisphere determine this division of labor.
City College of New York neurophysiologist Hysell Oviedo and colleagues studied auditory processing in mice in order to better understand the brain circuit features and neural computations between these lateralized processes.
“The human brain’s remarkable ability to simultaneously understand the lyrics of your favorite song and appreciate its musical qualities is poorly understood,” said Oviedo.
Oviedo and her colleagues screened mouse cortical connectivity and measured temporal integration differences between the left and right auditory cortex. They mapped activation of principal neurons in all cortical layers and found stronger activation in the superficial layers of the right auditory cortex compared to the left. The team also used novel statistical methods to demonstrate a link between stronger self-excitation and longer temporal integration. These findings indicate longer processing times in the right auditory cortex, a key feature in decoding slower components of speech and music.
Their results demonstrate a link between stronger synaptic connections and longer network time scales in the right hemisphere.
The study appears in the journal Plos Biology.
“These findings are an important advance in our understanding of language processing in the brain and could provide some insight into deficits observed in communication disorders,” said Oviedo. “Our results are particularly relevant to dyslexia, which appears to involve disruptions in the brain’s temporal processing of language. We now have a rudimentary understanding of what neural mechanisms could potentially be affected.”
About the City College of New York
Since 1847, The City College of New York has provided a high-quality and affordable education to generations of New Yorkers in a wide variety of disciplines. CCNY embraces its position at the forefront of social change. It is ranked #1 by the Harvard-based Opportunity Insights out of 369 selective public colleges in the United States on the overall mobility index. This measure reflects both access and outcomes, representing the likelihood that a student at CCNY can move up two or more income quintiles. Education research organization DegreeChoices ranks CCNY #3 nationally for social mobility. In addition, the Center for World University Rankings places CCNY in the top 1.8% of universities worldwide in terms of academic excellence. Labor analytics firm Emsi puts at $1.9 billion CCNY’s annual economic impact on the regional economy (5 boroughs and 5 adjacent counties) and quantifies the “for dollar” return on investment to students, taxpayers and society. At City College, more than 15,000 students pursue undergraduate and graduate degrees in eight schools and divisions, driven by significant funded research, creativity and scholarship. This year, CCNY launched its most expansive fundraising campaign, ever. The campaign, titled “Doing Remarkable Things Together” seeks to bring the College’s Foundation to more than $1 billion in total assets in support of the College mission. CCNY is as diverse, dynamic and visionary as New York City itself. View CCNY Media Kit.
Erica Rex
P: 845 668 0322
E:
erex@ccny.cuny.edu