Expectations of the timing and intensity of a stimulus propagate to the auditory periphery through the medial olivocochlear reflex

Abstract

Expectations concerning the timing of a stimulus enhance attention at the time at which the event occurs, which confers significant sensory and behavioral benefits. Herein, we show that temporal expectations modulate even the sensory transduction in the auditory periphery via the descending pathway. We measured the medial olivocochlear reflex (MOCR), a sound-activated efferent feedback that controls outer hair cell motility and optimizes the dynamic range of the sensory system. MOCR was noninvasively assessed using otoacoustic emissions. We found that the MOCR was enhanced by a visual cue presented at a fixed interval before a sound but was unaffected if the interval was changing between trials. The MOCR was also observed to be stronger when the learned timing expectation matched with the timing of the sound but remained unvaried when these two factors did not match. This implies that the MOCR can be voluntarily controlled in a stimulus- and goal-directed manner. Moreover, we found that the MOCR was enhanced by the expectation of a strong but not a weak, sound intensity. This asymmetrical enhancement could facilitate antimasking and noise protective effects without disrupting the detection of faint signals. Therefore, the descending pathway conveys temporal and intensity expectations to modulate auditory processing.

Deviance detection in subthalamic neural population responses to natural stimuli in bats

“…Given that wave ii and iii represent neural activity in the cochlear nucleus and superior olivary complex, respectively [14], this finding strongly supports the hypothesis that auditory probability encoding at population level is happening already below the inferior colliculus, as it has been suggested in former studies [8,15]. In fact, effects of novelty detection have recently been described for an even lower auditory structure, the cochlea [16,17]. In these reports, the authors propose that the medial olivocochlear reflex is responsible for those effects by suppressing outer hair cell activity, mediated by feedback from the cortex.…”

Release your inhibitions: how synaptic dynamics shape efferent activity in the auditory system

“…Learned expectations about stimulus properties influenced the intensity of the MOC reflex. This finding provides a small glimpse of the complexity of functions and tasks that MOC-mediated modulation could be involved in (Otsuka et al, 2022). Overall, the MOC efferent fibres seem to represent a common final route of a number of pathways that assert descending control on the inner ear.…”

“…In a recent paper, Otsuka et al. (2022) showed that the intensity of the MOC reflex can be controlled by goal‐oriented behaviour. Learned expectations about stimulus properties influenced the intensity of the MOC reflex.…”

“…Numerous studies have tried to directly show the benefit of top-down control via olivocochlear efferents in various listening tasks. In a recent paper, Otsuka et al (2022) showed that the intensity of the MOC reflex can be controlled by goal-oriented behaviour. Learned expectations about stimulus properties influenced the intensity of the MOC reflex.…”

Effect of temporal regularity of preceding sounds on medial olivocochlear reflex and reaction times

“…Slow-rate cortical oscillations synchronize with regularly presented stimuli [7], and their phases are aligned as a function of the temporal predictability of a sensory event [8]. We recently reported that the medial olivocochlear reflex (MOCR) is modulated by the presentation of visual cues that anticipate the arrival of a stimulus sound [9], suggesting that the most peripheral stage of the hearing system, the cochlea, can be modulated by temporal predictability.…”