Initial-state-dependent, robust, transient neural dynamics encode conscious visual perception

Abstract

Recent research has identified late-latency, long-lasting neural activity as a robust correlate of conscious perception. Yet, the dynamical nature of this activity is poorly understood, and the mechanisms governing its presence or absence and the associated conscious perception remain elusive. We applied dynamic-pattern analysis to whole-brain slow cortical dynamics recorded by magnetoencephalography (MEG) in human subjects performing a threshold-level visual perception task. Up to 1 second before stimulus onset, brain activity pattern across widespread cortices significantly predicted whether a threshold-level visual stimulus was later consciously perceived. This initial state of brain activity interacts nonlinearly with stimulus input to shape the evolving cortical activity trajectory, with seen and unseen trials following well separated trajectories. Furthermore, cortical activity trajectories during conscious perception are fast evolving and robust to small variations in the initial state. These results suggest that brain dynamics underlying conscious visual perception belongs to the class of initial-state-dependent, robust, transient neural dynamics. AUTHOR SUMMARYWhat brain mechanisms underlie conscious perception? A commonly adopted paradigm for studying this question is to present human subjects with threshold-level stimuli. When shown repeatedly, the same stimulus is sometimes consciously perceived, sometimes not. Using magnetoencephalography, we shed light on the neural mechanisms governing whether the stimulus is consciously perceived in a given trial. We observed that depending on the initial brain state defined by widespread activity pattern in the slow cortical potential (<5 Hz) range, a physically identical, brief (30 -60 ms) stimulus input triggers distinct sequences of activity pattern evolution over time that correspond to either consciously perceiving the stimulus or not. Such activity pattern evolution forms a "trajectory" in the state space and affords significant single-trial decoding of perceptual outcome from 1 sec before to 3 sec after stimulus onset. While previous theories on conscious perception have emphasized sustained, high-level activity, we found that brain dynamics underlying conscious perception exhibit fast-changing activity patterns. These peer-reviewed) is the author/funder. All rights reserved. No reuse allowed without permission.The copyright holder for this preprint (which was not . http://dx.doi.org/10.1101/133983 doi: bioRxiv preprint first posted online May. 3, 2017; 3 results significantly further our understanding on the neural mechanisms governing conscious access of a stimulus and the dynamical nature of neural activity underlying conscious perception.

Disrupted neural variability during propofol‐induced sedation and unconsciousness

“…Behaviorally, stronger TTV reduction is associated with faster reaction time (He, 2013), superior perceptual abilities (Arazi, Gonen-Yaacovi, & Dinstein, 2017;Baria, Maniscalco, & He, 2017;Schurger et al, 2015), and superior memory recall (Xue et al, 2010). Therefore, it is plausible to assume that neuronal mechanisms involved in TTV reduction contribute to the disambiguation of environmental signals and enhance the efficiency of cortical information processing (Churchland et al, 2010;Finn et al, 2007;Monier et al, 2003;White et al, 2012).…”

The hybrid nature of task-evoked activity: Inside-out neural dynamics in intracranial EEG and Deep Learning

“…György Buszáki (Buzsáki, 2019) suggests an alternative approach, ‘inside-out’; unlike the traditional ‘outside-in’, it places intrinsic neural activity as a key factor (inside) in modulating activity change related to external stimuli (outside) (see also Northoff et al 2010, Northoff 2014a and b). Consistent with this approach (Buzsáki, 2019), studies (He, 2013; Baria et al, 2017; Huang et al, 2017; Nieus et al, 2018; Galindo-Leon et al, 2019; Hirschmann et al, 2019; Podvalny et al, 2019) have demonstrated that poststimulus activity levels depend on the initial state, the level of prestimulus activity (Yamagishi et al, 2008; Mathewson et al, 2009; Northoff et al, 2010; Fellinger et al, 2011; Hanslmayr et al, 2013; He, 2013; Milton and Pleydell-Pearce, 2016; Benwell et al, 2017; Huang et al, 2017; Hirschmann et al, 2019). These findings demand the question: how and in what way do prestimulus activity levels shape stimulus-induced activity beyond the external stimulus?…”

The interplay between information flux and temporal dynamics in infraslow frequencies

“…The brain's spontaneous activity exhibits fluctuations in different frequency ranges. These include faster frequencies from 1Hz to 240Hz 23 as well as slower ones like the slow cortical potentials (0.1hz to 1Hz) which all can be measured using EEG or MEG [24][25][26][27][28] . These different frequencies have been associated with diverse functions including perception, attention, working memory, self, motivation, and consciousness (and various others) 23,29 .…”