The longstanding mystery of how selective hearing works how people can tune in to a single speaker while tuning out their crowded, noisy environs is solved this week in the journal Nature by two scientists from the University of California, San Francisco (UCSF).
Psychologists have known for decades about the so-called "cocktail party effect," a name that evokes the Mad Men era in which it was coined. It is the remarkable human ability to focus on a single speaker in virtually any environmenta classroom, sporting event or coffee bareven if that person's voice is seemingly drowned out by a jabbering crowd.
To understand how selective hearing works in the brain, UCSF neurosurgeon Edward Chang, MD, a faculty member in the UCSF Department of Neurological Surgery and the Keck Center for Integrative Neuroscience, and UCSF postdoctoral fellow Nima Mesgarani, PhD, worked with three patients who were undergoing brain surgery for severe epilepsy.
Part of this surgery involves pinpointing the parts of the brain responsible for disabling seizures. The UCSF epilepsy team finds those locales by mapping the brain's activity over a week, with a thin sheet of up to 256 electrodes placed under the skull on the brain's outer surface or cortex. These electrodes record activity in the temporal lobehome to the auditory cortex.
UCSF is one of few leading academic epilepsy centers where these advanced intracranial recordings are done, and, Chang said, the ability to safely record from the brain itself provides unique opportunities to advance our fundamental knowledge of how the brain works.
"The combination of high-resolution brain recordings and powerful decoding algorithms opens a window into the subjective experience of the mind that we've never seen before," Chang said.
In the experiments, patients listened to two speech samples played to them simultaneously in which different phrases were spoken by different sp
|Contact: Jason Socrates Bardi|
University of California - San Francisco