Alpha power and stimulus-evoked activity dissociate metacognitive reports of attention, visibility and confidence in a visual detection task

Variability in the detection and discrimination of weak visual stimuli has been linked to prestimulus neural activity. In particular, the power of oscillatory activity in the alpha-band (8-12 Hz) has been shown to impact upon the objective likelihood of stimulus detection, as well as measures of subjective visibility, attention, and decision confidence. We aimed to clarify how prestimulus alpha influences performance and phenomenology, by recording simultaneous subjective measures of attention and confidence (Experiment 1), or attention and visibility (Experiment 2) on a trial-by-trial basis in a visual detection task. Across both experiments, prestimulus alpha power was negatively and linearly correlated with the intensity of subjective attention. In contrast to this linear relationship, we observed a quadratic relationship between the strength of prestimulus alpha power and subjective ratings of confidence and visibility. We find that this same quadratic relationship links prestimulus alpha power to the strength of stimulus evoked responses. Visibility and confidence judgements corresponded to the strength of evoked responses, but confidence, uniquely, incorporated information about attentional state. As such, our findings reveal distinct psychological and neural correlates of metacognitive judgements of attentional state, stimulus visibility, and decision confidence.

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Causal modulation of right hemisphere fronto-parietal phase synchrony with Transcranial Magnetic Stimulation during a conscious visual detection task

Scientific Reports ◽

10.1038/s41598-020-79812-y ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Chloé Stengel ◽

Marine Vernet ◽

Julià L. Amengual ◽

Antoni Valero-Cabré

Keyword(s):

Transcranial Magnetic Stimulation ◽

Visual Perception ◽

Frequency Band ◽

Magnetic Stimulation ◽

Visual Detection ◽

Detection Task ◽

Oscillatory Activity ◽

Top Down ◽

The Right ◽

High Beta

AbstractCorrelational evidence in non-human primates has reported increases of fronto-parietal high-beta (22–30 Hz) synchrony during the top-down allocation of visuo-spatial attention. But may inter-regional synchronization at this specific frequency band provide a causal mechanism by which top-down attentional processes facilitate conscious visual perception? To address this question, we analyzed electroencephalographic (EEG) signals from a group of healthy participants who performed a conscious visual detection task while we delivered brief (4 pulses) rhythmic (30 Hz) or random bursts of Transcranial Magnetic Stimulation (TMS) to the right Frontal Eye Field (FEF) prior to the onset of a lateralized target. We report increases of inter-regional synchronization in the high-beta band (25–35 Hz) between the electrode closest to the stimulated region (the right FEF) and right parietal EEG leads, and increases of local inter-trial coherence within the same frequency band over bilateral parietal EEG contacts, both driven by rhythmic but not random TMS patterns. Such increases were accompained by improvements of conscious visual sensitivity for left visual targets in the rhythmic but not the random TMS condition. These outcomes suggest that high-beta inter-regional synchrony can be modulated non-invasively and that high-beta oscillatory activity across the right dorsal fronto-parietal network may contribute to the facilitation of conscious visual perception. Our work supports future applications of non-invasive brain stimulation to restore impaired visually-guided behaviors by operating on top-down attentional modulatory mechanisms.

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Causal modulation of right fronto-parietal phase synchrony with Transcranial Magnetic Stimulation during a conscious visual detection task

10.1101/859330 ◽

2019 ◽

Author(s):

Chloé Stengel ◽

Marine Vernet ◽

Julià L. Amengual ◽

Antoni Valero-Cabré

Keyword(s):

Transcranial Magnetic Stimulation ◽

Frequency Band ◽

Magnetic Stimulation ◽

Visual Detection ◽

Detection Task ◽

Oscillatory Activity ◽

Beta Band ◽

The Right ◽

High Beta ◽

Regional Synchrony

AbstractCorrelational evidence in non-human primates has reported evidence of increased frontoparietal high-beta band (22-30 Hz) synchrony during the endogenous allocation of visuospatial attention. But may the engagement of inter-regional synchrony at this specific frequency band provide the causal mechanism by which top-down processes are engaged and they facilitate visual perception in humans? Here we further analyzed electroencephalographic (EEG) signals from a group of healthy human participants who performed a conscious visual detection task, under the influence of brief rhythmic (30 Hz) or random bursts of Transcranial Magnetic Stimulation (TMS), with an identical number of pulses and duration, delivered to the right Frontal Eye Field (FEF) prior to the onset of a lateralized near-threshold target. We report increases of inter-regional synchronization in the high-beta band (25-35 Hz) between the electrode closest to the stimulated region (right FEF) and parietal leads, and increases of local inter-trial coherence in the same frequency band over parietal contacts, both driven by rhythmic but not random TMS patterns. Importantly, such increases were accompained by increases of visual sensitivity for left visual targets (contralateral to the stimulation) in the rhythmic but not the random TMS condition at the group level. These outcomes suggest that human high-beta synchrony between right frontal and parietal regions can be modulated non-invasively and that high-beta oscillatory activity across the right dorsal fronto-parietal network may contribute to the facilitation of conscious visual detection. Our study also supports future applications of non-invasive brain stimulation technologies for the manipulation of inter-regional synchrony, which could be administered to improve visual behaviors in healthy humans or neurological patients.

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Prestimulus Alpha Oscillations and the Temporal Sequencing of Audiovisual Events

Journal of Cognitive Neuroscience ◽

10.1162/jocn_a_01145 ◽

2017 ◽

Vol 29 (9) ◽

pp. 1566-1582 ◽

Cited By ~ 13

Author(s):

Laetitia Grabot ◽

Anne Kösem ◽

Leila Azizi ◽

Virginie van Wassenhove

Keyword(s):

Temporal Order ◽

Brain Activity ◽

Sensory Modality ◽

Oscillatory Activity ◽

Alpha Power ◽

Evoked Responses ◽

Point Of Subjective Simultaneity ◽

Temporal Sequencing ◽

Subjective Simultaneity ◽

Actual Sequence

Perceiving the temporal order of sensory events typically depends on participants' attentional state, thus likely on the endogenous fluctuations of brain activity. Using magnetoencephalography, we sought to determine whether spontaneous brain oscillations could disambiguate the perceived order of auditory and visual events presented in close temporal proximity, that is, at the individual's perceptual order threshold (Point of Subjective Simultaneity [PSS]). Two neural responses were found to index an individual's temporal order perception when contrasting brain activity as a function of perceived order (i.e., perceiving the sound first vs. perceiving the visual event first) given the same physical audiovisual sequence. First, average differences in prestimulus auditory alpha power indicated perceiving the correct ordering of audiovisual events irrespective of which sensory modality came first: a relatively low alpha power indicated perceiving auditory or visual first as a function of the actual sequence order. Additionally, the relative changes in the amplitude of the auditory (but not visual) evoked responses were correlated with participant's correct performance. Crucially, the sign of the magnitude difference in prestimulus alpha power and evoked responses between perceived audiovisual orders correlated with an individual's PSS. Taken together, our results suggest that spontaneous oscillatory activity cannot disambiguate subjective temporal order without prior knowledge of the individual's bias toward perceiving one or the other sensory modality first. Altogether, our results suggest that, under high perceptual uncertainty, the magnitude of prestimulus alpha (de)synchronization indicates the amount of compensation needed to overcome an individual's prior in the serial ordering and temporal sequencing of information.

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Prestimulus neural alpha power predicts confidence in discriminating identical tones

10.1101/285577 ◽

2018 ◽

Cited By ~ 1

Author(s):

Malte Wöstmann ◽

Leonhard Waschke ◽

Jonas Obleser

Keyword(s):

Task Performance ◽

Human Subjects ◽

Alpha Power ◽

Alpha Oscillations ◽

Decision Confidence ◽

Physical Evidence ◽

Neural Representations ◽

Evoked Activity ◽

And Performance ◽

Physically Identical

AbstractThere is growing evidence that the power of prestimulus neural alpha oscillations (∼10 Hz) holds information on a perceiver’s bias or confidence in an ensuing perceptual decision, rather than perceptual sensitivity per se. Obviously, however, confidence also depends on the physical evidence available in the stimulus as well as on task performance. If prestimulus alpha power has a direct impact on decision confidence, this link should hold independent of variations in stimulus evidence and performance. We tested this assertion in a paradigm where human listeners (n = 17) rated their confidence in the discrimination of the pitch of two identical tones. Lower prestimulus alpha power in the electroencephalogram (EEG) was predictive of higher confidence ratings, but not of the decision outcome (i.e., judging the first or the second tone as being higher in pitch). Importantly, the link between prestimulus alpha power and decision confidence was not mediated by auditory evoked activity. Our findings demonstrate that the link between prestimulus alpha power and decision confidence does not hinge on physical evidence in the stimulus or task performance. Instead, these results speak to a model wherein low prestimulus alpha power increases neural baseline excitability, which is reflected in enhanced stimulus-evoked neural responses and higher confidence.Significance statementIn order to understand the mechanistic relevance of neural oscillations for perception, we here relate these directly to changes in human auditory decision confidence. Human subjects rated their confidence in the discrimination of the pitch of two tones, which were, unbeknownst to the listener, physically identical. In the absence of changing evidence in the physical stimulus or changes in task performance, we demonstrate that prestimulus alpha power negatively relates to decision confidence. Our results support a model of cortical alpha oscillations as a proxy for neural baseline excitability in which lower prestimulus alpha power does not lead to more precise but rather to overall amplified neural representations.

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Alpha Oscillations Prior to Encoding Preferentially Modulate Memory Consolidation during Wake Relative to Sleep

10.1101/202176 ◽

2017 ◽

Cited By ~ 3

Author(s):

Zachariah R. Cross ◽

Amanda Santamaria ◽

Andrew W. Corcoran ◽

Phillip M. Alday ◽

Scott Coussens ◽

...

Keyword(s):

Memory Consolidation ◽

Memory Performance ◽

Oscillatory Activity ◽

Alpha Power ◽

Attentional State ◽

Linear Mixed Effects ◽

Cortical Regions ◽

Individual Alpha Frequency ◽

The Impact ◽

Flow Of Information

ABSTRACTSleep promotes memory consolidation through unique neuromodulatory activity. However, little is known about the impact of attention during pre-sleep memory encoding on later memory performance. The current study aimed to address the question of whether attentional state prior to encoding, as indexed by alpha oscillatory activity, modulates the consolidation of images across periods of sleep and wake. 22 participants aged 18 – 41 years (mean age = 27.3) viewed 120 emotionally valenced images (positive, negative, neutral) before a 2hr afternoon sleep opportunity and an equivalent period of wake. Following the sleep and wake conditions, participants were required to distinguish between 120 previously seen (target) images and 120 new (distractor) images. Relative alpha power – adjusted according to participants’ individual alpha frequency – was computed to index attentional state prior to the learning phase. Generalised linear mixed-effects modelling revealed memory performance was modulated by attention, such that greater pre-encoding alpha power preferentially promoted memory consolidation during wake compared to sleep. There was no difference in memory performance between positive, negative and neutral stimuli. Modulations in alpha oscillatory activity may help to coordinate the flow of information between task-relevant cortical regions and a thalamo-cortical loop that preferentially subserves the formation of memory during times of wake relative to sleep.

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Phase and power modulations on the amplitude of TMS-induced motor evoked potentials

PLoS ONE ◽

10.1371/journal.pone.0255815 ◽

2021 ◽

Vol 16 (9) ◽

pp. e0255815

Author(s):

Lukas Schilberg ◽

Sanne Ten Oever ◽

Teresa Schuhmann ◽

Alexander T. Sack

Keyword(s):

Evoked Potentials ◽

Diagnostic Tool ◽

Primary Motor Cortex ◽

Motor Evoked Potentials ◽

Single Pulse ◽

Beta Phase ◽

Alpha Phase ◽

Individual Variability ◽

Oscillatory Activity ◽

Alpha Power

The evaluation of transcranial magnetic stimulation (TMS)-induced motor evoked potentials (MEPs) promises valuable information about fundamental brain related mechanisms and may serve as a diagnostic tool for clinical monitoring of therapeutic progress or surgery procedures. However, reports about spontaneous fluctuations of MEP amplitudes causing high intra-individual variability have led to increased concerns about the reliability of this measure. One possible cause for high variability of MEPs could be neuronal oscillatory activity, which reflects fluctuations of membrane potentials that systematically increase and decrease the excitability of neuronal networks. Here, we investigate the dependence of MEP amplitude on oscillation power and phase by combining the application of single pulse TMS over the primary motor cortex with concurrent recordings of electromyography and electroencephalography. Our results show that MEP amplitude is correlated to alpha phase, alpha power as well as beta phase. These findings may help explain corticospinal excitability fluctuations by highlighting the modulatory effect of alpha and beta phase on MEPs. In the future, controlling for such a causal relationship may allow for the development of new protocols, improve this method as a (diagnostic) tool and increase the specificity and efficacy of general TMS applications.

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Attention for Speaking: Prestimulus Motor-cortical Alpha Power Predicts Picture Naming Latencies

Journal of Cognitive Neuroscience ◽

10.1162/jocn_a_01513 ◽

2020 ◽

Vol 32 (5) ◽

pp. 747-761

Author(s):

Suzanne R. Jongman ◽

Ardi Roelofs ◽

Ashley G. Lewis

Keyword(s):

Language Production ◽

Alpha Power ◽

Attentional State ◽

Inhibitory Function ◽

Manual Responses ◽

Picture Presentation ◽

Single Speaker ◽

Motor Cortical ◽

Cortical Regions ◽

Naming Latencies

There is a range of variability in the speed with which a single speaker will produce the same word from one instance to another. Individual differences studies have shown that the speed of production and the ability to maintain attention are related. This study investigated whether fluctuations in production latencies can be explained by spontaneous fluctuations in speakers' attention just prior to initiating speech planning. A relationship between individuals' incidental attentional state and response performance is well attested in visual perception, with lower prestimulus alpha power associated with faster manual responses. Alpha is thought to have an inhibitory function: Low alpha power suggests less inhibition of a specific brain region, whereas high alpha power suggests more inhibition. Does the same relationship hold for cognitively demanding tasks such as word production? In this study, participants named pictures while EEG was recorded, with alpha power taken to index an individual's momentary attentional state. Participants' level of alpha power just prior to picture presentation and just prior to speech onset predicted subsequent naming latencies. Specifically, higher alpha power in the motor system resulted in faster speech initiation. Our results suggest that one index of a lapse of attention during speaking is reduced inhibition of motor-cortical regions: Decreased motor-cortical alpha power indicates reduced inhibition of this area while early stages of production planning unfold, which leads to increased interference from motor-cortical signals and longer naming latencies. This study shows that the language production system is not impermeable to the influence of attention.

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Effectiveness of Accommodative Aids in Reducing Empty Field Myopia in Visual Search

Human Factors The Journal of the Human Factors and Ergonomics Society ◽

10.1177/001872087802000611 ◽

1978 ◽

Vol 20 (6) ◽

pp. 733-740 ◽

Cited By ~ 8

Author(s):

Michael L. Matthews ◽

Robert G. Angus ◽

Douglas G. Pearce

Keyword(s):

Visual Search ◽

Visual Detection ◽

Field Performance ◽

Detection Task ◽

Performance Loss ◽

Aircraft Cabin ◽

Search Area ◽

A Performance

When a visual detection task is performed with distant targets in the absence of adequate accommodative cues, a performance loss is obtained which has been attributed to empty field myopia. It is shown that in a visual search situation an accommodative aid located at optical infinity improves detection by approximately 30% over empty field performance. It is further demonstrated that such an aid may overcome the conflicting accommodative cues provided by proximal contours defining the search area, i.e., a situation that is analogous to the detection of distant targets by observers searching through aircraft cabin windows.

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