In binaural listening, the two cochleae do not act as independent sound receptors; their functioning is linked via the contralateral medial olivo-cochlear reflex (MOCR), which can be activated by contralateral sounds. The present study aimed at characterizing the effect of a contralateral white noise (CWN) on psychophysical tuning curves (PTCs). PTCs were measured in forward masking for probe frequencies of 500 Hz and 4 kHz, with and without CWN. The sound pressure level of the probe was fixed across conditions. PTCs for different response criteria were measured by using various masker-probe time gaps. The CWN had no significant effects on PTCs at 4 kHz. At 500 Hz, by contrast, PTCs measured with CWN appeared broader, particularly for short gaps, and they showed a decrease in the masker level. This decrease was greater the longer the masker-probe time gap. A computer model of forward masking with efferent control of cochlear gain was used to explain the data. The model accounted for the data based on the assumption that the sole effect of the CWN was to reduce the cochlear gain by ∼6.5 dB at 500 Hz for low and moderate levels. It also suggested that the pattern of data at 500 Hz is the result of combined broad bandwidth of compression and off-frequency listening. Results are discussed in relation with other physiological and psychoacoustical studies on the effect of activation of MOCR on cochlear function.
Basilar Membrane Automatic Speech Recognition System Masker Level Human Cochlea Linear Reference
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Work supported by a grant from the Spanish Ministry of Economy and Competitiveness (ref. BFU2009-07909) to EALP and by a doctoral studentship of the Chilean CONICYT to EA.
Aguilar E, Eustaquio-Martin A, Lopez-Poveda EA (2013) Contralateral efferent reflex effects on threshold and supra-threshold psychoacoustical tuning curves at low and high frequencies. J. Assoc. Res. Otolaryngol. DOI: 10.1007/s10162-013-0373-4Google Scholar
Bhagat SP, Carter PH (2010) Efferent-induced change in human cochlear compression and its influence on masking of tones. Neurosci Lett 485:94–97PubMedCrossRefGoogle Scholar
Ferry RT, Meddis R (2007) A computer model of medial efferent suppression in the mammalian auditory system. J Acoust Soc Am 122:3519–3526PubMedCrossRefGoogle Scholar
Francis NA, Guinan JJ Jr (2010) Acoustic stimulation of human medial olivocochlear efferents reduces stimulus-frequency and click-evoked otoacoustic emission delays: Implications for cochlear filter bandwidths. Hear Res 267:36–45PubMedCrossRefGoogle Scholar
Guinan JJ (2006) Olivocochlear efferents: anatomy, physiology, function, and the measurement of efferent effects in humans. Ear Hear 27:589–607PubMedCrossRefGoogle Scholar
Jennings SG, Strickland EA, Heinz MG (2009) Precursor effects on behavioral estimates of frequency selectivity and gain in forward masking. J Acoust Soc Am 125:2172–2181PubMedCrossRefGoogle Scholar
Lilaonitkul W, Guinan JJ Jr (2009) Human medial olivocochlear reflex: effects as functions of contralateral, ipsilateral, and bilateral elicitor bandwidths. J Assoc Res Otolaryngol 10:459–470PubMedCrossRefGoogle Scholar
Lopez-Poveda EA, Plack CJ, Meddis R (2003) Cochlear nonlinearity between 500 and 8000 Hz in listeners with normal hearing. J Acoust Soc Am 113:951–960PubMedCrossRefGoogle Scholar
Lopez-Poveda EA, Barrios LF, ves-Pinto A (2007) Psychophysical estimates of level-dependent best-frequency shifts in the apical region of the human basilar membrane. J Acoust Soc Am 121:3646–3654PubMedCrossRefGoogle Scholar
Meddis R, O’Mard L, Lopez-Poveda EA (2001) A computational algorithm for computing nonlinear auditory frequency selectivity. J Acoust Soc Am 109:2852–2861PubMedCrossRefGoogle Scholar
Nelson DA, Schroder AC, Wojtczak M (2001) A new procedure for measuring peripheral compression in normal-hearing and hearing-impaired listeners. J Acoust Soc Am 110:2045–2064PubMedCrossRefGoogle Scholar
Plack CJ, Oxenham AJ, Drga V (2002) Linear and nonlinear processes in temporal masking. Acta Acust/Acustica 88:348–358Google Scholar
Vinay, Moore BCJ (2008) Effects of activation of the efferent system on psychophysical tuning curves as a function of signal frequency. Hear Res 240:93–101PubMedCrossRefGoogle Scholar