The encoding of task-irrelevant but not relevant acoustic events depends on the pre-stimulus phase of alpha oscillations
Troby Ka-Yan Lui1,2 (firstname.lastname@example.org), Benedikt Zoefel1,2; 1Centre National de la Recherche Scientifique, 2Université de Toulouse III - Paul Sabatier
The phase of alpha oscillations has been associated with perceptual fluctuations in visual attention. In the auditory modality, however, neural phase and perception seemed uncorrelated in the absence of acoustic rhythms. Here, we hypothesized that this difference reflects the dynamic nature of audition: The momentary change in acoustic input renders it costly to lose the information that coincides with the low-excitability neural phase. We hypothesized that the brain employs constant (i.e. non-phasic) attention to upcoming task-relevant acoustic targets to avoid such information loss. In contrast, the perception of to-be-ignored task-irrelevant acoustic events would still be subject to the pre-stimulus neural phase. In this electroencephalography study, 29 human participants (21F) performed a target-in-noise detection task, wherein pure tones at two pitches were randomly presented amidst a continuous noise. Participants were instructed to detect the tone at one pitch and ignore the other. In line with our hypothesis, we found that neural response to the tone depends on the pre-stimulus alpha phase (9 – 12 Hz) only when the tone is task-irrelevant. The strongest phase dependence was evident in fronto-central and occipital sensors. Perceptual sensitivity was further associated with pre-stimulus alpha phase extracted from central sensors. These results demonstrate that rhythmic perception is restored in the face of task-irrelevant events in the auditory modality.
Topic Area: ATTENTION: Auditory
CNS Account Login
April 13–16 | 2024