The Tactile Window to Consciousness is Characterized by Frequency-Specific Integration and Segregation of the Primary Somatosensory Cortex

Frey, Julia; Ruhnau, Philipp; Leske, Sabine; Siegel, Markus; Braun, Christoph; Weisz, Nathan

doi:10.1038/srep20805

Cited by 22 publications

(19 citation statements)

References 50 publications

(83 reference statements)

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“…During the early time windows, gamma-band synchronization connected nodes only within the attention networks, after which the gamma-band network comprised also the SM system, including motor cortex (M1). This temporal pattern suggests that in the present task, attentional systems drive sensory perception in line with prior studies, which suggest that perception is related to differences in the prestimulus network properties (Weisz et al, 2014 ; Frey et al, 2016 ) and predicted by infraslow fluctuations of electrical activity (Monto et al, 2008 ). Furthermore, fMRI BOLD signal fluctuations in attentional but not in sensory system are also correlated with perceptual performance in a threshold-stimulus detection task like ours (Sadaghiani et al, 2009 ).…”

Section: Discussionsupporting

confidence: 87%

Dynamic large-scale network synchronization from perception to action

Hirvonen

Monto

Wang

et al. 2018

Network Neuroscience

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Sensory-guided actions entail the processing of sensory information, generation of perceptual decisions, and the generation of appropriate actions. Neuronal activity underlying these processes is distributed into sensory, fronto-parietal, and motor brain areas, respectively. How the neuronal processing is coordinated across these brain areas to support functions from perception to action remains unknown. We investigated whether phase synchronization in large-scale networks coordinate these processes. We recorded human cortical activity with magnetoencephalography (MEG) during a task in which weak somatosensory stimuli remained unperceived or were perceived. We then assessed dynamic evolution of phase synchronization in large-scale networks from source-reconstructed MEG data by using advanced analysis approaches combined with graph theory. Here we show that perceiving and reporting of weak somatosensory stimuli is correlated with sustained strengthening of large-scale synchrony concurrently in delta/theta (3–7 Hz) and gamma (40–60 Hz) frequency bands. In a data-driven network localization, we found this synchronization to dynamically connect the task-relevant, that is, the fronto-parietal, sensory, and motor systems. The strength and temporal pattern of interareal synchronization were also correlated with the response times. These data thus show that key brain areas underlying perception, decision-making, and actions are transiently connected by large-scale dynamic phase synchronization in the delta/theta and gamma bands.

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Section: Discussionsupporting

confidence: 87%

Dynamic large-scale network synchronization from perception to action

Hirvonen

Monto

Wang

et al. 2018

Network Neuroscience

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“…A recent fMRI study employing the Rubin face-vase stimulus (37) found that pre-and poststimulus neural activity was pronounced in the FFA and interpreted the observed prestimulus BOLD signal differences as differences in baseline excitability. Indeed, this interpretation is consistent with a large body of work that shows that alpha band activity in task-sensitive sensory regions, an index of neuronal excitability in those regions, predicts behavioral outcome (8,10,11,67). Yet, we found no differences in pre-stimulus alpha activity that could account for the behavioral outcome.…”

Section: Discussionsupporting

confidence: 84%

“…They help explain why repetitions of the same physical stimuli elicit different percepts and responses from trial to trial in both animals (1) and humans (2)(3)(4)(5). Both local excitability changes in task-relevant sensory regions (6,7) and neural network connectivity patterns have been shown to underlie trial-by-trial fluctuations in perception (8)(9)(10)(11).…”

Section: Introductionmentioning

confidence: 99%

“…The paradigms to study the impact of ongoing neural activity on perception typically involve near-threshold detection and discrimination tasks, in which pre-stimulus neural fluctuations influence the perceptual fate of stimuli, for example whether an object is seen ("Hit") or not ("Miss"; e.g. (8,(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)). Beyond mere stimulus detection and discrimination, one of the visual system's essential functions is to identify and categorize objects and, in this way, construct the content of visual experiences (19)(20)(21).…”

Section: Introductionmentioning

confidence: 99%

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Pre-stimulus feedback connectivity biases the content of visual experiences

Rassi

Wutz

Müller

et al. 2018

Preprint

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Ongoing fluctuations in neural excitability and in network-wide activity patterns before stimulus onset have been proposed to underlie variability in near-threshold stimulus detection paradigms, i.e. whether an object is perceived or not. Here, we investigated the impact of pre-stimulus neural fluctuations on the content of perception, i.e. whether one or another object is perceived. We recorded neural activity with magnetoencephalography before and while participants briefly viewed an ambiguous image, the Rubin face/vase illusion, and required them to report their perceived interpretation on each trial. Using multivariate pattern analysis, we showed robust decoding of the perceptual report during the post-stimulus period. Applying source localization to the classifier weights suggested early recruitment of V1 and ~160 ms recruitment of category-sensitive FFA. These poststimulus effects were accompanied by stronger oscillatory power in the gamma frequency band for face vs vase reports. In pre-stimulus intervals, we found no differences in oscillatory power between face vs. vase reports neither in V1 nor in FFA, indicating similar levels of neural excitability. Despite this, we found stronger connectivity between V1 and FFA prior to face reports for low-frequency oscillations. Specifically, the strength of pre-stimulus feedback connectivity (i.e. Granger causality) from FFA to V1 predicted not only the category of the upcoming percept, but also the strength of post-stimulus neural activity associated with the percept. Our work shows that pre-stimulus network states can help shape future processing in category-sensitive brain regions and in this way bias the content of visual experiences.

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“…In a framework for explaining prestimulus predispositions on conscious near-threshold perception (Ruhnau et al, 2014), we argue that network-level integration of a neural ensemble determines its propensity to impact downstream regions. In practice, network integration has been operationalized via graph theoretical metrics (Frey et al, 2016), providing support for the framework. Here, we expect that an analogous mechanism could determine how tACS could exert long-range effects.…”

Section: Introductionmentioning

confidence: 99%

Local Network-Level Integration Mediates Effects of Transcranial Alternating Current Stimulation

et al. 2018

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Transcranial alternating current stimulation (tACS) has been proposed as a tool to draw causal inferences on the role of oscillatory activity in cognitive functioning and has the potential to induce long-term changes in cerebral networks. However, effectiveness of tACS underlies high variability and dependencies, which, as previous modeling works have suggested, may be mediated by local and network-level brain states. We used magnetoencephalography to record brain activity from 17 healthy participants at rest as they kept their eyes open (EO) or eyes closed (EC) while being stimulated with sham, weak, or strong alpha-tACS using a montage commonly assumed to target occipital areas. We reconstructed the activity of sources in all stimulation conditions by means of beamforming. The analysis of resting-state brain activity revealed an interaction of the external stimulation with the endogenous alpha power increase from EO to EC. This interaction was localized to the posterior cingulate, a region remote from occipital cortex. This suggests state-dependent (EO vs. EC) long-range effects of tACS. In a follow-up analysis of this online-tACS effect, we find evidence that this state-dependency effect is mediated by functional network changes: connection strength from the precuneus was significantly correlated with the state-dependency effect in the posterior cingulate during tACS. No analogous correlation could be found for alpha power modulations in occipital cortex. Altogether, this is the first strong evidence to illustrate how functional network architectures can shape tACS effects.

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The Tactile Window to Consciousness is Characterized by Frequency-Specific Integration and Segregation of the Primary Somatosensory Cortex

Cited by 22 publications

References 50 publications

Dynamic large-scale network synchronization from perception to action

Dynamic large-scale network synchronization from perception to action

Pre-stimulus feedback connectivity biases the content of visual experiences

Local Network-Level Integration Mediates Effects of Transcranial Alternating Current Stimulation

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