Now, a team of researchers have used Functional Magnetic Resonance Imaging (fMRI) study to compare compared the representation of repetition rate across cortical and subcortical structures of the human auditory pathway using a wide range of rates. Stimuli were trains of repeated noise bursts with repetition rates ranging from low (where each burst could be resolved individually) to high (where individual bursts were not distinguishable and the train was perceived as a continuous, but modulated, sound). Noise bursts were chosen as the elemental stimulus based on the assumption that broadband sound would elicit robust responses by activating neurons across a wide range of characteristic frequencies. fMRI was selected for its high spatial resolution, its localizing capabilities, and its higher temporal resolution.
The authors of "Sound Repetition Rate in the Human Auditory Pathway: Representations in the Waveshape and Amplitude of fMRI Activation," are Michael P. Harms Ph.D. and Jennifer R. Melcher, Ph.D, both from the Eaton-Peabody Laboratory, Massachusetts Eye and Ear Infirmary, Boston, and the HarvardMassachusetts Institute of Technology Division of Health Sciences and Technology, Speech and Hearing Bioscience and Technology Program, Cambridge, MA. Dr. Melcher is also a member of the Department of Otology and Laryngology, Harvard Medical School, Boston, MA. Their findings appear in the Journal of Neurophysiology, a publication of the American Physiological Society (APS).
Methodology
A series of four experiments were conducted. The first two examined the effect of repetition rate on the response to a noise burst train in the inferior colliculus (IC), Heschl's gyrus (HG), and the superior temporal gyrus (STG) (experiment I); or the IC and m
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Contact: Donna Krupa
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American Physiological Society
12-Nov-2002