The Department of Psychology and The Center for Cognitive and Brain Sciences presents:
Dr. Nancy Kanwisher
Massachusetts Institute of Technology
The Functional Organization of Human Auditory Cortex
Although the functional organization of the ventral visual pathway has been revealed in great spatial and functional detail over the last twenty years, much less is known about high-level auditory cortex. I will describe work in collaboration with Sam Norman-Haignere and Josh McDermott using fMRI to investigate the functional organization of human auditory cortex. In addition to well-established tonotopic maps, we find evidence for a cortical region selectively responsive to pitch information that is present in the same location in virtually all subjects. Intriguingly, though, in collaborative work with Bevil Conway we do not find this region when the same fMRI contrasts is tested in macaques, providing important constaints on the functional significance, evolutionary origins, and availability of animal models for studying this region. Next, to explore the broader organization of auditory cortex in humans in a relatively hypothesis-neutral fashion, we have scanned people while they listen to a large set of familiar natural sounds, and used ICA to identify dominant profiles of response across this set. In addition to components for tonotopy and pitch, we find surprisingly selective components for speech and music, which cannot be acounted for by acoustic features. These components have distinct and consistent anatomical loci, anterior to primary auditory cortex (for music) and inferior (for speech). This work is starting to reveal the organization of human auditory cortex, which includes a numer of functionally specific components, including several that may be uniquely human.
