Fig. 2

Power analysis of OOA shows enhanced low-frequency power for auditory attention. Power analysis of cortical activity reveals enhanced alpha and beta power for auditory attention. a, b AMI of the cochlear frequency response for the left and right ear. The x-axis represents otoacoustic activity at sound frequencies from 1000 to 2000 Hz. The y-axis represents the frequency range of the FFT. On the right of each subplot, the OOA-AMI averaged over sound frequencies from 1000 to 2000 Hz is shown. The green and violet ticks illustrate the distribution of subjects’ peak frequencies from Figs. 1a, b. c OOA-AMI averaged over sound frequencies from 1000 to 2000 Hz and the range of subjects’ peak frequencies (3–10 Hz for the left and 1–10 Hz for right ear). The OOA-AMI is significantly higher for the Attend Auditory condition in the left (t₍₂₆₎ = 2.4701, p = 0.0204) and the right (t₍₂₆₎ = 2.3881, p = 0.0245) ear. There was no difference between ears (t₍₂₆₎ = − 0.8225, p = 0.4183). d A nonparametric cluster-based permutation analysis indicated an effect of condition for brain power pooled across 0.25–1.95 s of the cue-target interval (p = 0.004). This corresponded to a positive cluster in the observed data beginning around 4–6 Hz up to 24–25 Hz. The number of voxels in this cluster is shown as a function of frequency. The extent of the cluster is largest in the alpha and beta bands. Moreover, for both bands, it is located in posterior regions