Decoupled temporal variability and signal synchronization of spontaneous brain activity in loss of consciousness: An fMRI study in anesthesia

Huang, Zirui; Zhang, Jun; Wu, Jinsong; Qin, Pengmin; Wu, Xuehai; Wang, Zhiyao; Dai, Ruwei; Li, Yuan; Li, Weimin; Mao, Ying; Yang, Zhong; Zhang, Jianfeng; Wolff, Annemarie; Northoff, Georg

doi:10.1016/j.neuroimage.2015.08.062

Cited by 90 publications

(89 citation statements)

References 74 publications

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“…Propofol was our reference drug because it has been the most widely-used agent in human fMRI studies of anesthetic effects and we have considerable experience in this field 24,28,38,46–49 . The advantage of propofol is that it exerts minimal effects on cerebral and systemic hemodynamics 50,51 and therefore does not confound the fMRI results.…”

Section: Methodsmentioning

confidence: 99%

Brain imaging reveals covert consciousness during behavioral unresponsiveness induced by propofol

Huang

Vlisides

Tarnal

et al. 2018

Sci Rep

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Detecting covert consciousness in behaviorally unresponsive patients by brain imaging is of great interest, but a reproducible model and evidence from independent sources is still lacking. Here we demonstrate the possibility of using general anesthetics in a within-subjects study design to test methods or statistical paradigms of assessing covert consciousness. Using noninvasive neuroimaging in healthy volunteers, we identified a healthy study participant who was able to exhibit the specific fMRI signatures of volitional mental imagery while behaviorally unresponsive due to sedation with propofol. Our findings reveal a novel model that may accelerate the development of new approaches to reproducibly detect covert consciousness, which is difficult to achieve in patients with heterogeneous and sometimes clinically unstable neuropathology.

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Section: Methodsmentioning

confidence: 99%

Brain imaging reveals covert consciousness during behavioral unresponsiveness induced by propofol

Huang

Vlisides

Tarnal

et al. 2018

Sci Rep

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“…We addressed this issue in three steps. First, we calculated the indices of the amount of motion (shift and rotation) (Zang et al, 2007; Huang et al, 2016) for each subject, and then performed a one-way ANOVA among BS, LV, and SC. After this, no significant main effect was seen for either shift ( F = 1.55, p = 0.220) or rotation ( F = 2.86, p = 0.066).…”

Section: Methodsmentioning

confidence: 99%

“…More specifically, what alteration in spontaneous activity is related to hyperactivation in the blind? Besides rs-fMRI signal synchronization (e.g., functional connectivity), brain activities has another important property, namely, temporal variability (Kannurpatti and Biswal, 2008; Shew et al, 2009; Garrett et al, 2010, 2011; Kannurpatti et al, 2010; Vakorin et al, 2011; Huang et al, 2016). Recent temporal variability studies have provided insights in the human brain's dynamic function.…”

Section: Introductionmentioning

confidence: 99%

“…We studied 16 blind subjects (BS), 19 low-vision individuals (LV), and 21 normally sighted controls (SC) using both rs-fMRI and task-fMRI (see Table 1 for a full description of BS and LV). For rs-fMRI, two local features were investigated: (1) local signal synchronization measured by regional homogeneity (ReHo; Zang et al, 2004); and (2) temporal variability (TV) measured by the standard deviation of BOLD signal (Garrett et al, 2010, 2011, 2013a; Huang et al, 2016). For task-fMRI, we examined activation as subjects performed tactile pattern recognition (Pietrini et al, 2004; Cheung et al, 2009; Kitada et al, 2009).…”

Section: Introductionmentioning

confidence: 99%

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Interplay between Heightened Temporal Variability of Spontaneous Brain Activity and Task-Evoked Hyperactivation in the Blind

Dai

Huang

et al. 2016

Front. Hum. Neurosci.

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The brain's functional organization can be altered by visual deprivation. This is observed by comparing blind and sighted people's activation response to tactile discrimination tasks, like braille reading. Where, the blind have higher activation than the sighted upon tactile discrimination tasks, especially high activation difference is seen in ventral occipitotemporal (vOT) cortex. However, it remains unknown, whether this vOT hyperactivation is related to alteration of spontaneous activity. To address this question, we examined 16 blind subjects, 19 low-vision individuals, and 21 normally sighted controls using functional magnetic resonance imaging (fMRI). Subjects were scanned in resting-state and discrimination tactile task. In spontaneous activity, when compared to sighted subjects, we found both blind and low vision subjects had increased local signal synchronization and increased temporal variability. During tactile tasks, compared to sighted subjects, blind and low-vision subject's vOT had stronger tactile task-induced activation. Furthermore, through inter-subject partial correlation analysis, we found temporal variability is more related to tactile-task activation, than local signal synchronization's relation to tactile-induced activation. Our results further support that vision impairment induces vOT cortical reorganization. The hyperactivation in the vOT during tactile stimulus processing in the blind may be related to their greater dynamic range of spontaneous activity.

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“…What is it in sets of neuronal discharges that could be a color or a smell? Moreover, many patterns of neural activities are known to be deprived of any conscious correlate (Bodart et al, 2017;Silverstein et al 2015;Huang et al, 2016) and no obvious reason has been found as to why some other patterns would have such correlates. Complexity has been proposed as an answer to this question (e.g., Tononi & Edelman, 1998), but in and of itself, it is difficult to understand why a quale, such as red, would emerge when neural activity patterns become more complex or when the activities of several cortical areas become related to each other (as in Dehaene et al 2014).…”

Section: Introductionmentioning

confidence: 99%

Effects of Stimulus Processing on Event-Related Brain Potentials of Close Others

Haffar¹,

Pantecouteau²,

Bouten³

et al. 2018

Preprint

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We take what we see, hear, smell and feel for the reality. However, as neuroscientists, we know that this reality, that is, our perceptual world, is in fact made up by the brain from the processing of the nerve impulses coming from receptors. Ancient Greeks used to think that this perceptual world, sometimes called our 3D movie (Chalmers), is emitted and has its own physical nature. Given how real the 3D movie looks to us, it is still difficult today to consider that all we would be dealing with would be patterns of brain activity The present study thus aimed at testing whether the perceptual world could have some physical existence in addition to that of the neural patterns responsible for it. To achieve that goal, we tried to see whether brains could be sensitive to the 3D movie of others. This, admittedly unusual, operational hypothesis was based on two assumptions. First, brains are sensitive to the 3D movie, as our experience includes reactions to our perceptual world. Second, the physicality at stake does not differ across individuals. We recorded the event-related brain potentials (ERPs) evoked by stimuli of the international affective picture system in pairs of closely-related participants. Most importantly, they could neither see the stimuli simultaneously presented to their partners nor their reactions to them. As in Bouten et al. (2015), around 400 ms after the onset of the stimuli, ERPs started being more positive in inconsistent conditions. Namely, when the two subjects of each pair were presented with the same stimulus whereas they were told it would be a different one and vice-versa (i.e., different-stimuli expected to be same). ERPs were less positive when the two subjects of a pair were presented with the same stimuli and were told they were the same and conversely (i.e., different-stimuli expected to be different). The same experiment was then run in pairs of strangers. No significant effect of consistency on ERPs was observed even though participants could, this time, see, in the very periphery of their visual field, the reactions of their partner to the stimuli. We thus use the results of both studies to support a new version of the emission theory of consciousness and to suggest that the sensitivity to the perceptual world of others may depend on their prior familiarity with it.Preprints (www.preprints.org) | NOT PEER-REVIEWED | Posted:

show abstract

Decoupled temporal variability and signal synchronization of spontaneous brain activity in loss of consciousness: An fMRI study in anesthesia

Cited by 90 publications

References 74 publications

Brain imaging reveals covert consciousness during behavioral unresponsiveness induced by propofol

Brain imaging reveals covert consciousness during behavioral unresponsiveness induced by propofol

Interplay between Heightened Temporal Variability of Spontaneous Brain Activity and Task-Evoked Hyperactivation in the Blind

Effects of Stimulus Processing on Event-Related Brain Potentials of Close Others

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