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Abstract #2180

Noninvasive FMRI Investigation of Interaural Level Difference Processing in the Rat Subcortex

Condon Lau1, 2, Jevin W. Zhang1, 2, Joe S. Cheng1, 2, Kyle K. Xing1, 2, Iris Y. Zhou1, 2, Matthew M. Cheung1, 2, Ed X. Wu1, 2

1Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Hong Kong, Hong Kong SAR, China; 2Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong, Hong Kong SAR, China

Interaural level differences (ILDs) are important features for sound localization. Sound arrives at the ears with different sound pressure levels (SPLs) depending on the azimuth of the source. fMRI with seven ILD settings spanning 18dB (higher SPL in left ear is positive) is used to examine a rat model of subcortical ILD processing. Results show the inferior colliculus and dorsal lateral lemniscus contralateral to the higher SPL ear respond with larger signal change. This asymmetry is not apparent in the cochlear nucleus and superior olivary complex. These findings demonstrate fMRI is an effective tool for examining subcortical ILD processing.