The phase of ongoing oscillations mediates the causal relation between brain excitation and visual perception.

“In addition to alpha power, the phase of ongoing alphaoscillations predicts perception at phosphene threshold [25].”

“…of Neurology, Moscow, Russia, 3 Department of Neurosurgery, University Hospital of Zurich, University of Zurich, Zurich, Switzerland, 4 Laboratory of Neuroscience and Molecular Pharmacology, Institute of Translational Biomedicine, Saint Petersburg State University, Saint Petersburg, Russia, 5…”

“Recent evidence in the visual domain demonstrated that visual perception varies as a function of the phase of ongoing visual alpha oscillations [19–21,75,76].”

“…VanRullen, 2010; Dugué et al., 2015a, 2016; Landau et al., 2015), perception (e.g., Ergenoglu et al., 2004; Busch et al., 2009; Romei et al., 2010; Dugué et al., 2011b), and memory (e.g., Jensen et al., 2002; Bonnefond and Jensen, 2012), have been correlated to oscillations in specific brain areas…”

“The alpha-band rhythm (8–12 Hz) is particularly relevant for the understanding of visual perception as the alpha cycle modulates perceptual detection rates (Valera et al., 1981; Dugué et al., 2011).”

“This absence contrastswith the robust role of pre-stimulus alpha phase in visual perception for near-threshold stimuli (Busch et al., 2009; Dugue et al., 2011; Mathewson et al., 2009) and may be due to differences in task requirements or statistical power issues.”

“2008) and intra-individual variability in phosphene perception is driven in part by endogenous fluctuations in prestimulus α-band power and phase (Romei, Brodbeck, et al. 2008; Dugué et al. 2011; Romei et al. 2012).”

“…performance during perception and attention tasks on pre-stimulus phases in the lower frequency range (Busch et al., 2009; Busch & VanRullen, 2010; Dugué et al., 2011; Dugué, Marque, & VanRullen, 2015a; Fakche et al., 2021; Mathewson et al., 2009), post-stimulus phase-locking (Dugué, Marque, &…”

“These findings are in accordance with previous reports linking relatively lower occipito-parietal alpha power and certain alpha phases to higher cortical excitability and better visual sensitivity (Romei et al., 2008; Mathewson et al., 2009; Dugue et al., 2011; Lange et al., 2013).”

“Yet, other investigations have found similar pre-trial alpha phase effects in occipital sensors (Mathewson et al., 2009, Dugué et al., 2011).”

“…on the down-going phase of the alpha oscillation than on the up-going phase (Haegens et al., 2011), and transcranial magnetic stimulation (TMS)-induced phosphene detection is greater during the trough than the peak of the alpha oscillation recorded in the human visual cortex (Dugue et al., 2011).”

“These are ongoing rhythms of the visual cortex, thought to be the readiness state of the visual areas of the brain, and involved in controlling perception (119), termed a ‘window of excitability’ (120).”

“Intriguingly, our finding on prestimulus alpha phase match the results of a previous EEG study (Dugué et al., 2011), in which prestimulus alphaband activity in both posterior and frontalcentral electrodes predicted phosphene perception evoked by near- threshold transcranial magnetic stimulation.”

“exogenous attention manipulation (1), and also similar to dual-pulse protocols that have been successfully used before in visual perception and attention tasks (66,77,80).”

“…2013), which has already been suggested based on attentional phase effects on perception (Busch et al., 2009; Busch and VanRullen, 2010), reaction time (Drewes and VanRullen, 2011; Huang et al., 2015; Song et al., 2014) and perceptual variability in TMS-induced effects (Dugue et al., 2015, 2011).”

“Thirdly, intrinsic excitability fluctuations may differ considerably across cortical regions (Dugu ´ e et al., 2011; Gal et al., 2010; Johnson et al., 2012).”

“Alpha phase has also been associated with behavioral performance related to visual perception (Dugue et al., 2011; Mathewson et al., 2009), but the brain regions underlying such phase effects are yet to be identified (Palva & Palva, 2011).”

“This average was then compared with a surrogate distribution obtained with a permutation procedure (Dugué et al., 2011a, 2015; VanRullen, 2016b) consisting in shuffling the perceived-phosphene and unperceived-phosphene labels (5000 repetitions) and recalculating phase-locking values (including…”

“Importantly, phase dynamics in both delta [Besle et al., 2011; Schroeder and Lakatos, 2009] as well as in alpha [Drewes and Vanrullen, 2011; Dugue et al., 2011] bands have been shown to regulate neuronal excitability fluctuations and thereby to support sensory perception of attended information.”

“It is thus non-trivial that similar alpha power/phase effects on conscious experience (phosphene perception) were found in these studies (Romei et al., 2008a; Dugué et al., 2011).”

“…our data support the proposal that fluctuation in the phase of an underlying oscillation effectively creates " windows of excitability " during which the brain, or a particular brain area, is in a state that is more open to perturbation or communication with other brain areas (Dugué et al. 2011).”

“In particular, TMS and tACS have emerged as powerful tools for causally probing the involvement of alpha rhythms in a frequency-and region-specific manner (Dugu ´ e et al., 2011).”

“…by means of single-pulse transcranial magnetic stimulation (TMS) have been shown to be modulated by both spontaneous trial-to-trial variations (Romei et al., 2008a) and inter-individual differences (Romei et al., 2008b) in pre-stimulus posterior alpha power and alpha phase (Dugué et al., 2011).”

“Similarly, alpha phase predicts whether or not participants will experience a TMS induced occipital phosphene (Dugué et al., 2011).”

“In humans, the variability of neural response and behavioral performance has been shown to depend on ongoing endogenous and experimentally induced neural oscillations (Dugué et al., 2011; Fellinger et al., 2011; VanRullen et al., 2011; Neuling et al., 2012; Riecke et al., 2015).”

“A recent TMS EEG study has assured a frequency specific phase modulation in the alpha band range before stimulus onset [25].”

“For example, the model could be modified for developing a phosphene tresholding procedure over the occipital cortex (Dugué et al., 2011; Herring et al., 2015).”

“…magnetic stimulation (TMS) between (Romei et al., 2008a) as well as within subjects: participants were more likely to report a “phosphene” (illusory percept) when the ongoing EEG alpha power was (relatively) lower (Romei et al., 2008a, replicated by Dugué et al., 2011 and Samaha et al., 2017).”

“This may be of interest, for example in order to explain brain activity and behavior after an event, given a rhythms phase at the moment of that event [11, 12, 13, 14, 15, 16, 17, 18].”

“…www.frontiersin.org November 2013 | Volume 7 | Article 767 | 6 “fnhum-07-00767” — 2013/11/18 — 11:00 — page 7 — #7 been identified in the phase locking of ongoing brain oscillations (Dugué et al., 2011), the encoding of different aspects of the stimulus by different frequencies (“multiplexing;””

“…and phase has been studied using transcranial magnetic stimulation (TMS) and electroencephalography (EEG): an illusory percept (a “phosphene”) was most likely to occur when the TMS pulse was applied at a certain phase of the ongoing EEG oscillation than at the opposite phase (Dugué et al., 2011).”

“It has been proposed that perception is discrete and cyclic in a manner of perceptual cycles [15,16,45,61,62].”

“, 2009), saccadic reaction times to a peripheral target (Drewes and VanRullen, 2011), and the detection of a TMS-induced phosphene (Dugué et al., 2011) all depend on the phase of occipital alpha oscillations immediately preceding stimulus onset.”

“Correlation of EEG phase with binding performance We subsequently examined the effect of neural oscillatory phases, specifically before stimulus onset (Busch et al., 2009; Mathewson et al., 2009; Dugué et al., 2011; Chakravarthi and VanRullen, 2012), on slow attentional binding performance.”

“The alpha band is thought to control the processing of visual stimuli and has been called the ‘window of excitability’ (Dugue et al., 2011).”

“(2014) extended this idea and proposed that neural oscillations provide windows of opportunity for stimulus processing (Dugué et al., 2011).”

“The relevance of these alpha oscillations had already been probed with TMS by demonstrating that their power (Romei et al., 2008) and phase (Dugué et al., 2011) at TMS pulse onset directly reflected visual cortex excitability as measured by phosphene perception.”

“This proposal is primarily based on observations in the visual domain (e.g., Dugué et al., 2011; Dugué & VanRullen, 2014; Fiebelkorn et al., 2013; Huang et al., 2015; Landau et al., 2015; Landau & Fries, 2012; Song, Meng, Chen, Zhou, & Luo, 2014), but evidence has also accumulated in the auditory…”

“The relationship between these sampling rhythms and perception has been corroborated using magneto- and electro-encephalography (M/EEG) in humans, in particular by observing a consistent relationship between oscillations of the alpha rhythms (8–12 Hz) and sensitivity to new visual input (Busch et al., 2009; Dugué et a…”

“Scalp topographies from pre-stimulus time points (Figure 2, right panel) indicate an occipital and frontal distribution, consistent with the scalp distribution of the effects of alpha-band phase on visual cortex excitability inferred from TMS-EEG experiments (Dugué et al., 2011; Samaha et al., 2017).”

“Nonetheless, recent findings demonstrate that perceptual sampling of visual stimuli is primarily determined by the frequency of individual alpha band activity (Dugué et al., 2011; Chakravarthi and Vanrullen, 2012; Cecere et al., 2015; Samaha and Postle, 2015).”

“…oscillations have been reliably associated with many cognitive processes, such as perception (Arnal & Giraud, 2012; VanRullen & MacDonald, 2012; Dugué, Marque, & VanRullen, 2011), memory (Lundqvist, Herman, Warden, Brincat, & Miller, 2018; Benchenane, Tiesinga, & Battaglia, 2011), attention…”

“A growing body of evidence suggests that alpha band oscillations can exert critical influence on neuronal function and perception (Dugué et al. 2011; Jensen and Mazaheri 2010; Weisz et al. 2011).”

“Rhythmic activity in the alpha band (8–13 Hz) is a core feature of cortical communication (59) and cognition (60) and was demonstrated in various studies to modulate neural firing (61), perceptual detection rates (62, 63), and cerebral blood flow (64).”

“The phase of alpha and/or beta oscillations can also modulate perceptual processing (Busch et al. 2009; Mathewson et al. 2009; Dugue et al. 2011; Ng et al. 2012), and some investigators have speculated that each cycle of an alpha oscillation encodes the output of an individual perceptual sample or quantum (Baumgarten…”

“An individual’s alpha band oscillations are thought to act as a "window of excitability" [153].”

“The phase synchronisation is indeed crucial as the perception level is highly dependent on the phase at which the stimulus is presented [68].”

“In addition to oscillatory amplitude, its phase is involved in visual processing (VanRullen and Koch 2003; Busch et al. 2009;Mathewson et al. 2009; Dugue et al. 2011).”

“Many of the paradigms (Dugu (cid:1) e et al., 2011; McLelland et al., 2016; Van Rullen, 2016) employing this methodology reported the existence of an intrinsic rhythm in behavioral performance fluctuating at approximately 10 Hz.”

“The ENMod consisted of a wearable headband with 3 EEG channels roughly corresponding to Fp1, Fp2, and Fpz according to the 10–20 convention and was controlled by a custom smartphone application.”

“A range of visual perceptions has been shown to correlate with the phase of the posterior rhythm (Varela et al., 1981; Busch et al., 2009; Mathewson et al., 2009; Dugué et al., 2011; Sokoliuk and VanRullen, 2013).”

“We first replicated previous results showing that pre78 stimulus phase [20,32,55-63] and post-stimulus phase-locking across trials [20,64,65] of low79 frequency oscillations predict successful task performance (same task as in [20]).”

“A particularly elegant approach to investigate this relationship has been applied in a study which assessed the role of the alpha phase on the perception of phosphenes, an illusory percept that was directly evoked in the visual cortex by means of single-pulse transcranial magnetic stimulation (TMS; Dugue et al., 2011).”

“For example rhythmic transcranial magnetic stimulation can entrain intrinsic cortical alpha rhythms (Thut et al. 2011), affecting perception (Dugué et al. 2011) as well as concomitantly modifying frontal/ parietal alpha power and coherence and psychotic symptomology in SZ (Jin et al. 2006; 2011).”

“Phosphenes artificially induced by TMS are more detectable in lower prestimulus alpha power and specific alpha phase ranges (Dugue et al., 2011; Romei et al., 2008; Samaha, Gosseries, & Postle, 2017).”

“For example, a single pulse of TMS (spTMS) to the occipital cortex is more likely to evoke a phosphene when applied during peak alpha phase (Dugue et al., 2011) and neural entrainment to 10 Hz-TMS (i.”

“, 2020) and using non-invasive transcranial magnetic stimulation (TMS) in sighted humans (Dugue et al., 2011), but the feasibility of LFP phase-locked stimulation with intracortical electrodes in humans still remains unexplored.”