[Modification of cochlear active micromechanism by auditory cortex].
OBJECTIVE
To investigate the modification of active micromechanism of outer hair cells by auditory cortex.


METHODS
1. Effects of selective attention on distortion product otoacoustic emissions (DPOAE) were analyzed in 9 human subjects with normal hearing. Visual tasks, two letters, O and Q, were alternatively displayed on a computer screen. Letter Q was target stimulus flashing randomly (probability was 20%), and letter O was non-target stimulus occurring regularly (probability was 80%). 2. In 13 guinea pigs, DPOAEs were measured before and after decerebration.


RESULTS
1. Visual tasks suppressed DPOAE significantly in both 1 kHz and 2 kHz (P < 0.05). 2. DPOAE reduced significantly in decerebrated guinea pigs.


CONCLUSIONS
The study further demonstrates that the efferents from the auditory cortex do innervate the cochlea, and the efferent pathway passes from the auditory cortex, the super olive complex to the cochlea. Through this pathway the auditory cortex modulates the cochlear active micromechanism. The underlying mechanism was discussed.
Wang
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Department of Otolaryngology, Union Hospital, Tongji Medical University, Wuhan 430022.
Zhong
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D000158:Acoustic Impedance Tests; D000328:Adult; D000818:Animals; D001303:Auditory Cortex / Q000502:physiology*; D003051:Cochlea / Q000166:cytology / Q000502:physiology*; D003655:Decerebrate State / Q000503:physiopathology; D005260:Female; D006168:Guinea Pigs; D018072:Hair Cells, Auditory, Outer / Q000502:physiology*; D006801:Humans; D008297:Male; D017084:Otoacoustic Emissions, Spontaneous