The general significance of the present study is spurred by the fact that the prevalence of communication difficulties increases dramatically with age and that by the year 2030 the elderly population will grow to about one-fifth of the U.S. total population. As an individual increases into and past the sixth decade of life, one of the consequences of aging is the gradual deterioration in auditory sensitivity, coupled with changes in central neurophysiological processes. The goal of this research is to search for neurophysiological mechanisms underlying known deficits in temporal processing. At the single cell level encoding of temporal acuity is mediated in part, by inhibitory neurotransmitters which are known to undergo an age-related decline in the auditory midbrain. The proposed experiments will manipulate the effects of specific inhibitory neurotransmitters which are known to be critical in determining response properties in the inferior colliculus, the major obligatory nucleus for ascending auditory information in the brainstem. It is hoped that the following specific objectives will provide new insight into the auditory deficits associated with presbycusis, eventually leading to effective treatment of sensorimotor problems in the elderly.
