When sinusoidal electric stimulation is applied to the intact cochlea, a

When sinusoidal electric stimulation is applied to the intact cochlea, a frequency-specific acoustic emission can be recorded in the ear canal. in belief of a tonal (rather than a broad-band or noisy) sound at a frequency of 8 kHz or above. I. Introduction That electrical stimulation produces mechanical changes in the organ of Corti was first described in the pioneering studies of Moxon (1971), who reported frequency-specific and place-specific excitation, as well as acoustic masking of electrically-evoked responses. We have more recently learned that sinusoidal electric stimulation of the intact cochlea produces a frequency-specific RPS6KA6 otoacoustic emission (OAE) in the ear canal (see Hubbard and Hill, 1983; Xue em et al /em ., 1993; Ren and Nuttall, 1995; Nuttall and Ren, 1995; Nakajima em et al /em ., 1998; Nuttall em et al /em ., 2001; Reyes em et al /em ., 2001). These electrically evoked OAEs (EEOAEs) originate close to the site from the stimulating electrode (Xue em et al /em ., 1993; Ren and Nuttall, 1995; Nuttall em et al /em ., 2001), where regional electrical excitement induces motile response (contractile movement, or elongation) of outer locks cells (OHCs). That OHCs modification their form in response to electrical stimulation has been proven in cells dissociated through the body organ of Corti (Brownell em et al /em ., 1985; Kachar em et al /em ., 1986; Ashmore, 1987) and cells taken care of within a half-turn cochlear explant (Reuter and Zenner, 1990). In vivo electrical stimulation from the cochlea leads ARN-509 pontent inhibitor to OHC motile response resulting in basilar membrane movement (Nuttall and Dolan, 1993; Nuttall and Ren, 1995; Xue em et al /em ., 1995). The basilar membrane movement noticed by Nuttall and co-workers (Nuttall and Dolan, 1993; Nuttall and Ren, 1995) aswell as Xue et al. (1995) presumably moves in the change path as OAEs are made by change traveling motion from the basilar membrane (i.e., projecting toward the stapes, through the center ear, and in to the hearing canal, discover Kemp, 1978; Guinan and Shera, 1999). Nevertheless, electrically evoked motile response of OHCs also creates forwards traveling motion from the basilar membrane (i.e., on the helicotrema, see Dolan and Nuttall, 1993). Forward journeying waves produced in response to acoustic excitement result in internal locks cell (IHC) neurotransmitter discharge, neural activity, and a corresponding auditory feeling (hearing). Whenever a forwards traveling wave is certainly generated by electric excitement of OHCs, we presume that there surely is a matching auditory percept, which includes been suggested as electromotile hearing (Nuttall and Ren, 1995). This function uses psychophysical procedures of function to straight check the hypothesis that ARN-509 pontent inhibitor there surely is an auditory percept connected with electomotile hearing, and additional, the fact that percept is certainly a tonal acoustic feeling. We examined EEOAE generation inside our subjects to verify that electrical excitement created an EEOAE (which really is a less invasive way of measuring traveling wave era in the cochlea than immediate dimension of basilar membrane movement) as well as the acoustic feeling evaluated with ARN-509 pontent inhibitor psychophysical techniques. The EEOAE data ARN-509 pontent inhibitor shown here provide crucial evidence the fact that electrical excitement paradigm we utilized generated EEOAE responses that were equivalent to those in other studies. II. MATERIALS AND METHODS A. Subjects Adult male guinea pigs (Elm Hill Breeding Labs, Chelmsford, MA) ARN-509 pontent inhibitor were individually housed with free access to water. All subjects weighed 300-350 grams at the onset of the experimental procedures. Weight gain was continual until subjects achieved a excess weight of at least 900 grams. Food intake (Purina Guinea.