Oscillatory infrasonic modulation of the cochlear amplifier by selective attention

Abstract

21 Evidence shows that selective attention to visual stimuli modulates the gain of 22 cochlear responses, probably through auditory-cortex descending pathways. At the cerebral 23 cortex level, amplitude and phase changes of neural oscillations have been proposed as a 24 correlate of selective attention. However, whether sensory receptors are also influenced by 25 the oscillatory network during attention tasks remains unknown. Here, we searched for 26 oscillatory attention-related activity at the cochlear receptor in humans. We used an 27 alternating visual/auditory selective attention task and measured electroencephalographic 28 activity simultaneously to distortion product otoacoustic emissions (a measure of cochlear 29 receptor-cell activity). In order to search for cochlear oscillatory activity, the otoacoustic 30 emission signal, was included as an additional channel in the electroencephalogram 31 analyses. This method allowed us to study dynamic changes of cochlear oscillations in the 32 same range of frequencies (1-35 Hz) in which cognitive effects are commonly observed in 33 electroencephalogram works. We found the presence of low frequency (<10 Hz) brain and 34 cochlear amplifier oscillations during periods of selective attention to visual and auditory 35 stimuli. Notably, switching between auditory and visual attention modulates the amplitude 36 and the temporal order of brain and inner ear oscillations. These results extend the role of 37 the oscillatory activity network during cognition in neural systems to the receptor level.38

Cochlear activity in silent cue-target intervals shows a theta-rhythmic pattern and is correlated to attentional alpha modulations

“…In contrast, Dragicevic et al (2019) reported significant correlations between the oscillatory DPOAE signal and cortical oscillations at low frequencies (< 10 Hz) mainly when attention was switched from the visual to the auditory modality.…”

“…In line with previous studies that found reduced levels of OAEs in subjects attending to a visual task, our results resemble an elevation of the to-be-attended acoustic stimulus during acoustic selective attention (Froehlich, Collet, Valatx, & Morgon, 1993;Meric & Collet, 1992;Puel, Rebillard, Bonfils, & Pujol, 1989;Wittekindt et al, 2014;see Smith et al (2012) for an exception). Particularly, one study consistently reported similar amplitude modulations at low frequencies (< 7 Hz; Dragicevic et al, 2019). Yet, thus far, all studies on humans that have investigated effects of attention on the cochlea in cue-target periods utilized different types of evoked OAEs (EOAE) and distortion product OAEs (DPOAE).…”

“…Given the uniqueness of the auditory system in having cortical descending projections from primary auditory cortex (via IC and SOC) to the cochlea, it is conceivable that a putative mechanism of alternating attentional states directly affecting cochlear processes could exist. To pursue our aims we adapted an previously introduced approach for investigating cochlear otoacoustic activity (Dragicevic et al, 2019) that allows us to draw first conclusions on how cortical attention processes are linked to cochlear otoacoustic activity. We demonstrate the presence of a theta-rhythmic pattern of otoacoustic activity during silent periods when attention was focused on either upcoming auditory or visual targets.…”

“…However, the described effects are restricted to soundevoked responses, are small, and sometimes contradictory (Francis et al, 2018;Meric & Collet, 1992). Furthermore, the attention research on cortical and cochlear processes has been conducted largely independently (see Wittekindt et al (2014), Dragicevic et al (2019), or Riecke et al (2020) for exceptions). In summary, it remains unclear whether and how attention modulates cochlear processes during silent periods and how these peripheral processes are linked to cortical processes.…”

“…Given that attentional modulations of cortical oscillations are mostly found at low frequencies (< 30 Hz), we decided to use a similar analysis approach for the OOA-signal as Dragicevic et al (2019), an approach that allows us to investigate oscillatory cochlear activity at the same frequencies as cortical activity occurs. Further, genuine periodic components (peaks) of the OOA-signal were computed for the OOA (Haller et al, 2018).…”