부산대학교 도서관

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.heares.2005.01.005 Byline: Monica L. Hawley (a)(b), Jennifer R. Melcher (a)(b)(c), Barbara C. Fullerton (a)(b)(c) Abstract: Few neuro-imaging studies of the auditory system have examined the dependence of brain activation on sound bandwidth, a fundamental stimulus parameter, and none have examined bandwidth dependencies in the brainstem. The present study examined the effect of bandwidth on human brainstem activation using fMRI, an indicator of population neural activity. The studied stimuli (broadband, two-, one-, and third-octave continuous noise) activated three brainstem centers: cochlear nucleus, superior olivary complex, and inferior colliculus. Activation could be confidently attributed to these nuclei because it was appropriately punctate (given the small size of the imaged nuclei) and appropriately located (as determined from histological atlases). Activation in all three imaged centers increased monotonically with increasing bandwidth when either stimulus spectrum level or energy was held constant. Supplementary experiments indicated that the measured bandwidth dependencies were not contaminated by the extraneous sounds produced by the scanner. Increases in fMRI activation with increasing bandwidth would be expected from populations of neurons having a single best frequency and only excitatory responses to sound, but not necessarily from lower auditory system neurons with their often more complex responses. Our results provide basic information for designing auditory neuro-imaging studies that need to control for, or manipulate sound bandwidth. Author Affiliation: (a) Eaton-Peabody Laboratory, Massachusetts Eye and Ear Infirmary, 243 Charles Street, Boston, MA 02114, USA (b) Harvard-MIT Division of Health Sciences and Technology, Speech and Hearing Bioscience and Technology Program, Cambridge MA, USA (c) Department of Otology and Laryngology, Harvard Medical School, Boston MA, USA Article Note: (footnote) [star] Portions of this work were presented at the 25th Annual Meeting of the Association for Research in Otolaryngology (2002) and the 7th Annual Meeting of the Organization for Human Brain Mapping (2001).