EYE MOVEMENT-RELATED EARDRUM OSCILLATIONS (EMREOS) OCCUR WITHOUT VISUAL INPUT BUT ARE REDUCED DURING CLOSED EYELIDS

Recent investigations have shown that the tympanic membranes exhibit synchronous oscillations with each saccadic eye movement (Gruters et al., 2018), a phenomenon known as eye movement-related eardrum oscillations (EMREOs). However, the dependence of these saccade-associated EMREOs on ongoing visual activity remains to be elucidated. Given the direct projections from motor areas to primary auditory and visual cortices and the observation that EMREO’s onset occurs concurrently with, or even precedes, saccades, we hypothesized that EMREOs would persist in the absence of visual stimulation. We recruited sixteen healthy participants who executed horizontal saccades under three distinct conditions: i) in a well-lit environment, ii) in a darkened environment with eyes open, and iii) in a darkened environment with eyes closed. Tympanic movements were measured through in-ear microphones, and eye movements were measured through electrooculography. The results demonstrated the presence of EMREOs concurrent with both visually guided and memory-guided saccades, although a minor diminution in amplitude was observed in the 'dark with open eyes' condition. Further attenuation of EMREOs was evident when participants performed saccades with their eyelids closed, despite maintaining the same saccade amplitude and initial velocity. This amplitude reduction may reflect modulations in cortical states associated with predictive coding.
Acknowledgments: This work was supported in part by The National Center for Artificial Intelligence CENIA, Chile FB210017, Fundación Guillermo Puelma, and ANID-Subdirección de Capital Humano/Doctorado Nacional/2022-folio 21221549