Cochlear theta activity oscillates in phase opposition during interaural attention

Abstract

It is widely established that sensory perception is a rhythmic process as opposed to a continuous one. In the context of auditory perception this effect is only established on a cortical and behavioral level. Yet, the unique architecture of the auditory sensory system allows its primary sensory cortex to modulate the processes of its sensory receptors at the cochlear level. Previously, we could demonstrate the existence of a genuine cochlear theta (~6 Hz) rhythm that is modulated in amplitude by intermodal selective attention. As the study's paradigm was not suited to assess attentional effects on the oscillatory phase of cochlear activity the question whether attention can also affect the temporal organization of the cochlea's ongoing activity remained open. The present study utilizes an interaural attention paradigm to investigate ongoing otoacoustic activity during a stimulus-free cue-target interval and an omission period of the auditory target. We were able to replicate the existence of the cochlear theta rhythm. Importantly, we found significant phase opposition between the two ears and attention conditions of anticipatory as well as cochlear oscillatory activity during target presentation. Yet, the amplitude was unaffected by interaural attention. These results are the first to demonstrate that intermodal and interaural attention deploy different aspects of excitation and inhibition at the first level of auditory processing. While intermodal attention modulates the level of cochlear activity, interaural attention modulates the timing.

Eye movements track prioritized auditory features in selective attention to natural speech

“…This idea is supported by recent evidence in humans demonstrating a top-down modulation of the auditory periphery by selective attention (e.g. Gehmacher et al, 2022;Köhler et al, 2021;Köhler & Weisz, 2022) and could also explain why, in the current study, we observed the reported ocular speech tracking effects even without any meaningful visual information. Further studies could investigate potential effects / benefits of matching visual input (videos), e.g.…”