Eye Movement-Related Eardrum Oscillations (EMREOs) Occur without Visual Input But Are Reduced during Closed Eyelids

Area of Science:

• Neuroscience
• Auditory Neuroscience
• Oculomotor Research

Background:

• Eye movement-related eardrum oscillations (EMREOs) are synchronous with saccadic eye movements.
• The influence of visual activity on EMREOs is not fully understood.
• EMREOs' timing suggests potential links to motor and sensory cortices.

Purpose of the Study:

• To investigate if EMREOs persist in the absence of visual stimulation.
• To determine the impact of visual input and eye state on EMREOs.
• To explore the role of cortical states in modulating EMREOs.

Main Methods:

• Sixteen healthy participants performed horizontal saccades under three conditions: light, dark (eyes open), and dark (eyes closed).
• Ocular movements were recorded using electrooculography.
• Tympanic membrane oscillations were measured with in-ear microphones.

Main Results:

• EMREOs were present during visually guided and memory-guided saccades.
• A minor amplitude reduction in EMREOs was observed in the dark with eyes open.
• EMREOs showed significant amplitude attenuation with eyes closed, despite consistent saccade metrics.

Conclusions:

• EMREOs are not solely driven by visual stimuli and occur independently of visual input.
• The amplitude of EMREOs is modulated by cortical states, particularly during saccades with eyes closed.
• Findings suggest EMREOs involve complex interactions between motor activity, sensory processing, and predictive coding mechanisms.