Examination of the relationship between otoacoustic emissions and electroencephalography under inhibition of return

When an exogenous cue is presented to the left or right side, attention is oriented to the cued side immediately. However, after hundreds of milliseconds, attention shifts to the opposite side naturally. This attentional transition is inhibition of return (IOR). Our previous study indicates that theshorter reaction time, i.e., paying more attention to the attended ear, the smaller OAE at the same side during IOR. The IOR-related changes in the auditory periphery are assumed to be underlain by top-down cortical control via centrifugal nerves from cortex to the auditory periphery. To investigate whether and how cortical regions contribute to OAE changes, we measured OAE and EEG simultaneously during IOR. We found that OAE increased at attended ear compared to unattended ear when alpha power was more suppressed at unattended side of the occipital lobe during IOR (n = 12). The lateralized alpha power suppression in the occipital lobe is theorized to reflect the suppression of information from unattended side. The enhancement of auditory peripheral response at unsuppressed side may help the attentional gating process at cortical level.