Electromotile hearing: acoustic tones mask psychophysical response to high-frequency electrical stimulation of intact guinea pig cochleae.
When sinusoidal electric stimulation is applied to the intact cochlea, a frequency-specific acoustic emission can be recorded in the ear canal. Acoustic emissions are produced by basilar membrane motion, and have been used to suggest a corresponding acoustic sensation termed "electromotile hearing." Electromotile hearing has been specifically attributed to electric stimulation of outer hair cells in the intact organ of Corti. To determine the nature of the auditory perception produced by electric stimulation of a cochlea with intact outer hair cells, guinea pigs were tested in a psychophysical task. First, subjects were trained to report detection of sinusoidal acoustic stimuli and dynamic range was assessed using response latency. Subjects were then implanted with a ball electrode placed into scala tympani. Following the surgical implant procedure, subjects were transferred to a task in which acoustic signals were replaced by sinusoidal electric stimulation, and dynamic range was assessed again. Finally, the ability of acoustic pure-tone stimuli to mask the detection of the electric signals was assessed. Based on the masking effects, it is concluded that sinusoidal electric stimulation of the intact cochlea results in perception of a tonal (rather than a broadband or noisy) sound at a frequency of 8 kHz or above.
Le Prell
Colleen G
CG
Kresge Hearing Research Institute, 1301 East Ann Street, Ann Arbor, Michigan 48109-0506, USA. colleeng@umich.edu
Kawamoto
Kohei
K
Raphael
Yehoash
Y
Dolan
David F
DF
D000162:Acoustics; D000818:Animals; D003051:Cochlea / Q000502:physiology*; D004558:Electric Stimulation / Q000295:instrumentation; D006168:Guinea Pigs; D006309:Hearing / Q000502:physiology*; D017084:Otoacoustic Emissions, Spontaneous / Q000502:physiology; D010470:Perceptual Masking / Q000502:physiology*; D011601:Psychophysics / Q000706:statistics & numerical data; D011846:Radio Waves