Is Off-Frequency Overshoot Caused by Adaptation of Suppression?

Abstract

This study is concerned with the mechanism of off-frequency overshoot. Overshoot refers to the phenomenon whereby a brief signal presented at the onset of a masker is easier to detect when the masker is preceded by a “precursor” sound (which is often the same as the masker). Overshoot is most prominent when the masker and precursor have a different frequency than the signal (henceforth referred to as “off-frequency overshoot”). It has been suggested that off-frequency overshoot is based on a similar mechanism as “enhancement,” which refers to the perceptual pop-out of a signal after presentation of a precursor that contains a spectral notch at the signal frequency; both have been proposed to be caused by a reduction in the suppressive masking of the signal as a result of the adaptive effect of the precursor (“adaptation of suppression”). In this study, we measured overshoot, suppression, and adaptation of suppression for a 4-kHz sinusoidal signal and a 4.75-kHz sinusoidal masker and precursor, using the same set of participants. We show that, while the precursor yielded strong overshoot and the masker produced strong suppression, the precursor did not appear to cause any reduction (adaptation) of suppression. Predictions based on an established model of the cochlear input–output function indicate that our failure to obtain any adaptation of suppression is unlikely to represent a false negative outcome. Our results indicate that off-frequency overshoot and enhancement are likely caused by different mechanisms. We argue that overshoot may be due to higher-order perceptual factors such as transient masking or attentional diversion, whereas enhancement may be based on mechanisms similar to those that generate the Zwicker tone.

Olivocochlear Efferents in Animals and Humans: From Anatomy to Clinical Relevance

“…( 143 , 144 )]. The most recent studies, however, provide compelling evidence that overshoot is unrelated with an MOC-related reduction in cochlear gain and undermine the link between overshoot and MOC efferents [( 137 , 147 , 148 ); see also Ref. ( 149 )].…”

Effects of age and hearing loss on overshoot

“…Differences in the GOM slope between the 2-and 198-ms delay conditions and the finding that overshoot is decreased in listeners with cochlear hearing loss are difficult to explain by theories of overshoot based on confusion effects (Carlyon and White, 1992;Fletcher et al, 2015). These theories posit that overshoot is due to confusion between the onset of the probe and the onset of the masker (i.e., "transient masking"; Bacon and Moore, 1987).…”

“…Several peripheral (Smith and Zwislocki, 1975;Schmidt and Zwicker, 1991;von Klitzing and Kohlrausch, 1994;Strickland, 2001) and central (Carlyon and White, 1992;Fletcher et al, 2015) mechanisms have been proposed to explain overshoot. Of these mechanisms, the medial olivocochlear (MOC) reflex is most consistent with a reduction in cochlear amplifier gain, as suggested by psychophysical studies (Schmidt and Zwicker, 1991;Turner and Doherty, 1997;Bacon and Healy, 2000;Strickland, 2001Strickland, , 2004Strickland, , 2008Jennings et al, 2011).…”

Temporal Effects on Monaural Amplitude-Modulation Sensitivity in Ipsilateral, Contralateral and Bilateral Noise

“…Many studies have suggested that the MOCR could be the major contributor to overshoot (Jennings et al 2011(Jennings et al , 2016McFadden et al 2010;Schmidt and Zwicker 1991;Strickland 2001Strickland , 2004von Klitzing and Kohlrausch 1994;Walsh et al 2010). Other studies, however, have suggested that overshoot is unlikely related to the MOCR and is instead mediated by central auditory processes (Fletcher et al 2013(Fletcher et al , 2015Keefe et al 2009;Verschooten et al 2017).…”