Gary W. Harding

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Fibroblast growth factor receptor 3 (Fgfr3) is a tyrosine kinase receptor expressed in developing bone, cochlea, brain and spinal cord. Achondroplasia, the most common genetic form of dwarfism, is caused by mutations in FGFR3. Here we show that mice homozygous for a targeted disruption of Fgfr3 exhibit skeletal and inner ear defects. Skeletal defects(More)
An anatomically based frequency-place map was created for the mouse using C57BL/CBA F1 hybrids by matching noise-induced lesions in the organ of Corti with permanent hearing losses as determined by auditory brainstem response (ABR) thresholds. Twenty-six mice developed 'notched' ABR threshold shifts after exposure to an octave band of noise with a center(More)
The sense of balance is one of the phylogenetically oldest sensory systems. The vestibular organs, consisting of sensory hair cells and an overlying extracellular membrane, have been conserved throughout vertebrate evolution. To better understand mechanisms regulating vestibular development and mechanisms of vestibular pathophysiology, we have analyzed the(More)
PURPOSE To determine if noise damage in the organ of Corti is different in the low- and high-frequency regions of the cochlea. MATERIALS AND METHODS Chinchillas were exposed for 2 to 432 days to a 0.5 (low-frequency) or 4 kHz (high-frequency) octave band of noise at 47 to 95 dB sound pressure level. Auditory thresholds were determined before, during, and(More)
This study extended the findings of Ketten et al. [Ann. Otol. Rhinol. Laryngol. Suppl. 175:1–16 (1998)] by estimating the three-dimensional (3D) cochlear lengths, electrode array intracochlear insertion depths, and characteristic frequency ranges for 13 more Nucleus-22 implant recipients based on in vivo computed tomography (CT) scans. Array insertion(More)
Using morphological criteria, death pathways in outer hair cells (OHCs) were determined in chinchilla organs of Corti that had been exposed to a high- or moderate-level octave band of noise (OBN) centered at either 0.5 or 4-kHz. The specimens were part of our large collection of plastic-embedded flat preparations of chinchilla cochleae. Three death pathways(More)
The structural changes associated with noise-induced temporary threshold shift (TTS) were compared to the damage associated with permanent threshold shift (PTS). A within-animal paradigm involving survival-fixation was used to minimize problems with data interpretation from interanimal variability in response to noise. Auditory brainstem response thresholds(More)
1. The laminar and temporal distribution of synaptic activity supplied by forward and feedback connections between different areas of rat visual cortex was determined with the use of current source density (CSD) analysis in in vitro slices. In forward connections, synaptic potentials were evoked by electrically stimulating area 17 and recording in the(More)
The present study was designed to determine the response to noise of the auditory system of a genetically well-defined laboratory mouse in preparation for examining the effect of noise on mice with specific genetic mutations. The mice were C57BL/CBA F1 hybrids. Eight mice served as non-noise-exposed controls and 39 mice were exposed for 1-24 h to an octave(More)