Perceptual Oscillation of Audiovisual Time Simultaneity

Abstract

Action and perception are tightly coupled systems requiring coordination and synchronization over time. How the brain achieves synchronization is still a matter of debate, but recent experiments suggest that brain oscillations may play an important role in this process. Brain oscillations have been also proposed to be fundamental in determining time perception. Here, we had subjects perform an audiovisual temporal order judgment task to investigate the fine dynamics of temporal bias and sensitivity before and after the execution of voluntary hand movement (button-press). The reported order of the audiovisual sequence was rhythmically biased as a function of delay from hand action execution. Importantly, we found that it oscillated at a theta range frequency, starting ∼500 ms before and persisting ∼250 ms after the button-press, with consistent phase-locking across participants. Our results show that the perception of cross-sensory simultaneity oscillates rhythmically in synchrony with the programming phase of a voluntary action, demonstrating a link between action preparation and bias in temporal perceptual judgments.

Neural correlates of subjective timing precision and confidence

“…Another possibility is that sub-cortical brain activity is influential, as this can go undetected by scalp-recordings of EEG 13 . Timing information might also be encoded via oscillatory activity 14 , which would have been smoothed by the averaging of data across trials when creating signatures for decoding.…”

“…We regard the external possibilities we have mentioned as targets for future research, and are pleased to note that other researchers can begin to investigate these matters by reanalysing the data our results are based upon -freely available, with analysis scripts, via UQeSpace (https:// espace.library.uq.edu.au/). We anticipate that frequency-based analyses might be a particularly fruitful line of enquiry, given data suggesting AV synchrony perception can fluctuate at a specific duty cycle 14 . We also note that our results will need to be replicated with larger sample sizes, before we can be fully confident that they are generally representative of humans.…”

Propagation and update of auditory perceptual priors through alpha and theta rhythms

“…On each trial, 2 seconds of binaural broadband white-noise (randomly generated each trial and uncorrelated between the two ears) were presented together with the monaural target tone. The noise burst served to reset potential oscillations, similar to a visual or auditory cue (Fiebelkorn et al, 2011;Fiebelkorn et al, 2013;Landau & Fries, 2012;Re et al, 2019) and action or saccadic execution (Benedetto et al, 2016(Benedetto et al, , 2018Benedetto & Morrone, 2017;Tomassini et al, 2015Tomassini et al, , 2017. During the 2-s noise burst, within 0.2-1.2 s from noise onset, the target (1000 Hz, 10 ms) was delivered randomly with a probability of 80 % to one ear and 20 % to the other ear.…”

“…Oscillations of perceptual performance (typically measured by accuracy) have been demonstrated with various visual tasks (Benedetto et al, 2016(Benedetto et al, , 2018Fiebelkorn et al, 2011;Fiebelkorn et al, 2013;Landau & Fries, 2012;Re et al, 2019;Tomassini et al, 2015). These rhythmic fluctuations are thought to arise from an attentional sampling mechanism involving slow-frequency brain rhythms in the theta (4-8 Hz) and alpha (8-12 Hz) frequency range (Fiebelkorn & Kastner, 2019;Landau, 2018;VanRullen, 2016).…”

Auditory perceptual history is communicated through alpha oscillations

“…we used a different approach which does not require data binning but allows for an estimation 5 of participants' sensitivity and response bias based on single trials (for similar approaches, 6 see (Benedetto et al, 2018;Tomassini et al, 2017). As illustrated in Fig.…”