Delta/Theta band EEG activity shapes the rhythmic perceptual sampling of auditory scenes

Abstract

Many studies speak in favor of a rhythmic mode of listening, by which the encoding of acoustic information is structured by rhythmic neural processes at the time scale of about 1 to 4 Hz. Indeed, psychophysical data suggest that humans sample acoustic information in extended soundscapes not uniformly, but weigh the evidence at different moments for their perceptual decision at the time scale of about 2 Hz. We here test the critical prediction that such rhythmic perceptual sampling is directly related to the state of ongoing brain activity prior to the stimulus. Human participants judged the direction of frequency sweeps in 1.2 s long soundscapes while their EEG was recorded. Computing the perceptual weights attributed to different epochs within these soundscapes contingent on the phase or power of pre-stimulus oscillatory EEG activity revealed a direct link between the 4Hz EEG phase and power prior to the stimulus and the phase of the rhythmic component of these perceptual weights. Hence, the temporal pattern by which the acoustic information is sampled over time for behavior is directly related to pre-stimulus brain activity in the delta/theta band. These results close a gap in the mechanistic picture linking ongoing delta band activity with their role in shaping the segmentation and perceptual influence of subsequent acoustic information.

Slow neural oscillations explain temporal fluctuations in distractibility

“…Fluctuations of distractibility at 3 -5 Hz in the current study unveil the dynamic nature of attention, which was underappreciated in the static spotlight metaphor of attention (Posner et al, 1980). The attentional sampling of to-be-attended external stimuli (Fiebelkorn et al, 2013;Ho et al, 2017;Kubetschek & Kayser, 2021) or internal memory representation (Cruzat et al, 2021;Schmid et al, 2022;ter Wal et al, 2021) has been shown to exhibit temporal fluctuations at similar frequencies. The waxing and waning of attentional sampling may index inter-areal coordination between the attentional network and the sensory areas of the brain (Dugué & VanRullen, 2017), which is associated with the alternation between stronger and weaker attentional sampling over time (Fiebelkorn & Kastner, 2019).…”

“…With distractor-evoked behavioural and neural measures, we were able to encapsulate the temporal trajectory of distraction, which fluctuates on a subsecond temporal scale consistent with the rate of rhythmic sampling in attention (Fiebelkorn et al, 2013;Ho et al, 2017;Kubetschek & Kayser, 2021;Landau & Fries, 2012) and working memory (Cruzat et al, 2021;Schmid et al, 2022;ter Wal et al, 2021). With analysis of pre-distractor neural oscillatory phase, we were able to trace this distractibility back to a slow neural oscillatory fluctuation in inferior frontal and insular cortex (see below for an in-depth discussion).…”

“…Originally assumed to be static (Posner et al, 1980), the attentional spotlight was proposed to be blinking at a subsecond time scale in a theta-like rhythm (i.e., 3 -8 Hz) (Buschman & Kastner, 2015;Fiebelkorn & Kastner, 2019). Behaviourally, it is manifested via the waxing and waning of behavioural performance in target selection (Fiebelkorn et al, 2013;Ho et al, 2017;Kubetschek & Kayser, 2021;Landau & Fries, 2012) or working memory (Schmid et al, 2022;ter Wal et al, 2021) performance at similar frequencies. However, the temporal dynamics outside of the attentional spotlight are not well understood.…”