Investigating the role of the medial olivocochlear reflex in selective attention

Abstract

Selective attention can dramatically attenuate the cortical responses to unattended stimuli relative to attended stimuli. The mechanisms behind this attenuation and their locus in the auditory pathways are not yet understood. Recent animal work suggests that changes may begin to occur as early as the cochlea itself, potentially through the medial olivocochlear (MOC) reflex. Since measuring MOC activity directly is too invasive to be done in humans, otoacoustic emissions (OAEs) are used to examine changes in cochlear function. Previous investigations of attention-related efferent effects on cochlear processing using OAEs have generally found small and inconsistent effects. The previous lack of effects could be due in part to shortcomings in OAE and MOC-reflex measurement methodology. A new experimental paradigm designed to overcome these shortcomings was used here to examine the effects of selectively attending to visual or auditory stimuli. Participants directed attention to either low-frequency tones, hi...