The research program focuses on the neural processing of complex sounds such as speech, and how this processing changes in acoustically cluttered environments (background noise), and as a function of age.  Perhaps the most sophisticated task of the auditory nervous system is to encode vocalizations such as speech, particularly in real world, noisy environments.  We have shown, in human subject experimentation that this ability declines with age, even in select elderly subjects with good sensitivity to simple sounds.  Multidisciplinary, bioengineering research activities center on the following areas:

• Neurophysiological, systems analysis investigations of sound processing in the ear and brain at the single-nerve cell and evoked potential levels.  Contemporary methodologies include utilization of otoacoustic emissions that provide a measure of inner ear health and sound-processing capabilities and feedback function from the brain to the ear.
• Functional neuroanatomical organization of the central auditory system, investigated with advanced neuroimaging techniques in conjunction with light microscopy analysis of brain sections.  These allow visualization of neural pathways, neurochemicals and the neuropeptides that play a role in cellular functioning related to sensory processing and hearing, and changes with aging.
• Neuroscience and molecular genetic investigations of the neural bases of presbycusis – age-related hearing loss. Multidisciplinary NIH Program Project in collaboration with other faculty at the University of Rochester Neurobiology & Anatomy and Brain & Cognitive Sciences Depts., Center for Aging & Developmental Biology, and the National Technical Institute for the Deaf and Electrical Engineering Dept. at the Rochester Institute of Technology.  This program involves perceptual, behavioral, and electrophysiological studies that parallel animal experimentation incorporating behavior, neurophysiology, quantitative neuroanatomy, neural and cellular imaging, neurochemistry/pharmacology, gene microarray studies, and inner ear gene therapy.

•  Zettel ML, Zhu X, O'Neill W E, Frisina RD,  Age-related Decline in Kv3.1b Expression in the Mouse Auditory Brainstem Correlates with Functional Deficits in the Medial Olivocochlear Efferent System.   J Assoc Res Otolaryngol, (2007), 8:280-93.

•  Tadros SF, D'Souza M, Zettel ML, Zhu X, Lynch-Erhardt M, Frisina RD,  Serotonin 2B receptor: upregulated with age and hearing loss in mouse auditory system.   Neurobiol Aging, (2007), 28:1112-23.

•  Tadros SF, D'Souza M, Zettel ML, Zhu X, Waxmonsky NC, Frisina RD,  Glutamate-related gene expression changes with age in the mouse auditory midbrain.   Brain Res, (2007), 1127:1-9.

•  Frisina RD, Newman SR, Zhu X,  Auditory efferent activation in CBA mice exceeds that of C57s for varying levels of noise.   J Acoust Soc Am, (2007), 121:EL29-34.

•  Zhu X, Vasilyeva ON, Kim S, Jacobson M, Romney J, Waterman MS, Tuttle D, Frisina RD,  Auditory efferent feedback system deficits precede age-related hearing loss: Contralateral suppression of otoacoustic emissions in mice.   J Comp Neurol, (2007), 503:593-604.

•  Guimaraes P, Frisina ST, Mapes F, Tadros SF, Frisina DR, Frisina RD,  Progestin negatively affects hearing in aged women.   Proc Natl Acad Sci U S A, (2006), 103:14246-9.

•  Frisina RD, Walton JP,  Age-related structural and functional changes in the cochlear nucleus.   Hear Res, (2006), 216-217:216-23.

•  Tadros SF, D'Souza M, Zettel ML, Zhu X, Lynch-Erhardt M, Frisina RD,  Serotonin 2B receptor: Upregulated with age and hearing loss in mouse auditory system.   Neurobiol Aging, (2006), .

•  Thompson SK, Zhu X, Frisina RD,  Estrogen blockade reduces auditory feedback in CBA mice.   Otolaryngol Head Neck Surg, (2006), 135:100-5.

•  Frisina ST, Mapes F, Kim S, Frisina DR, Frisina RD,  Characterization of hearing loss in aged type II diabetics.   Hear Res, (2006), 211:103-13.

•  Tadros SF, Frisina ST, Mapes F, Frisina DR, Frisina RD,  Higher serum aldosterone correlates with lower hearing thresholds: a possible protective hormone against presbycusis.   Hear Res, (2005), 209:10-8.

•  Varghese GI, Zhu X, Frisina RD,  Age-related declines in distortion product otoacoustic emissions utilizing pure tone contralateral stimulation in CBA/CaJ mice.   Hear Res, (2005), 209:60-7.

•  Tadros SF, Frisina ST, Mapes F, Kim S, Frisina DR, Frisina RD,  Loss of peripheral right-ear advantage in age-related hearing loss.   Audiol Neurootol, (2005), 10:44-52.