Consistency and dynamical changes of directional information flow in different brain states: A comparison of working memory and resting-state using EEG

Wang, Ruimin; Ge, Sheng; Zommara, Noha Mohsen; Ravienna, Karine; Espinoza, Teodora; Iramina, Keiji

doi:10.1016/j.neuroimage.2019.116188

Cited by 17 publications

(16 citation statements)

References 62 publications

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“…Left posterior alpha power also increased in the Active group ( t = 2.16, P = 0.045), which, however, failed to survive the double contrast ( t = 1.36, P = 0.184). As evinced by recent neural computational and electrophysiological (including intracranial recordings) studies, alpha projections track a selective P→F direction (i.e., directed alpha P→F connectivity) via P→F cortical synchronization or traveling waves ( 15 , 21 , 22 , 32 – 36 ). We thus used Granger causality (GC) analysis to examine changes in this alpha connectivity.…”

Section: Resultsmentioning

confidence: 99%

“…As evinced by recent neural computational and electrophysiological (including intracranial recordings) studies, Right Posterior Power (a.u.) alpha projections track a selective P!F direction (i.e., directed alpha P!F connectivity) via P!F cortical synchronization or traveling waves (15,21,22,(32)(33)(34)(35)(36). We thus used Granger causality (GC) analysis to examine changes in this alpha connectivity.…”

Section: Resultsmentioning

confidence: 99%

“…However, network-level effects have been examined in only a handful of α-tACS-fMRI studies, which, using varied stimulation montages and protocols, have yielded ambiguous findings ( 39 – 41 ). Capitalizing on the selective P→F projection of alpha oscillations ( 15 , 21 , 22 , 32 – 36 ), we applied HD tACS for concentrated stimulation of alpha generators in the occipitoparietal cortex ( 42 ) to optimize network-level modulation. Intracranial current flow estimation (based on both a standard and a realistic head model) confirmed focal electrical fields in the targeted region.…”

Section: Discussionmentioning

confidence: 99%

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Transcranial stimulation of alpha oscillations up-regulates the default mode network

Clancy

Andrzejewski

You

et al. 2021

Proc. Natl. Acad. Sci. U.S.A.

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The default mode network (DMN) is the most-prominent intrinsic connectivity network, serving as a key architecture of the brain’s functional organization. Conversely, dysregulated DMN is characteristic of major neuropsychiatric disorders. However, the field still lacks mechanistic insights into the regulation of the DMN and effective interventions for DMN dysregulation. The current study approached this problem by manipulating neural synchrony, particularly alpha (8 to 12 Hz) oscillations, a dominant intrinsic oscillatory activity that has been increasingly associated with the DMN in both function and physiology. Using high-definition alpha-frequency transcranial alternating current stimulation (α-tACS) to stimulate the cortical source of alpha oscillations, in combination with simultaneous electroencephalography and functional MRI (EEG-fMRI), we demonstrated that α-tACS (versus Sham control) not only augmented EEG alpha oscillations but also strengthened fMRI and (source-level) alpha connectivity within the core of the DMN. Importantly, increase in alpha oscillations mediated the DMN connectivity enhancement. These findings thus identify a mechanistic link between alpha oscillations and DMN functioning. That transcranial alpha modulation can up-regulate the DMN further highlights an effective noninvasive intervention to normalize DMN functioning in various disorders.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Transcranial stimulation of alpha oscillations up-regulates the default mode network

Clancy

Andrzejewski

You

et al. 2021

Proc. Natl. Acad. Sci. U.S.A.

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“…An information theory metric, phase transfer entropy (PTE), was used to estimate the direction of information transfer in the 4-5 Hz frequency range 19,67 . PTE quantifies the mutual information between the past of signal ‘X’, X(t- τ ) and the present of signal ‘Y’, Y(t).…”

Section: Methodsmentioning

confidence: 99%

Theta mediated dynamics of human hippocampal-neocortical learning systems in memory formation and retrieval

Gattas,

Larson,

Mnatsakanyan

et al. 2023

Preprint

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Episodic memory arises as a function of dynamic interactions between the hippocampus and the neocortex, yet the mechanisms have remained elusive. Here, using human intracranial recordings during a mnemonic discrimination task, we report that 4-5 Hz (theta) power is differentially recruited during discrimination vs. overgeneralization, and its phase supports hippocampal-neocortical when memories are being formed and correctly retrieved. Interactions were largely bidirectional, with small but significant net directional biases; a hippocampus-to-neocortex bias during acquisition of new information that was subsequently correctly discriminated, and a neocortex-to-hippocampus bias during accurate discrimination of new stimuli from similar previously learned stimuli. The 4-5 Hz rhythm may facilitate the initial stages of information acquisition by neocortex during learning and the recall of stored information from cortex during retrieval. Future work should further probe these dynamics across different types of tasks and stimuli and computational models may need to be expanded accordingly to accommodate these findings.

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“…It is known that the local synchrony pattern varies remarkably across the cortex [ 12 ], and it has been reported that this regional variation is associated with the hierarchical organization of information processing during human functioning [ 13 ]. A direct measure of neural synchrony is spectral power, which measures the activity of the spatial sum of the cortical responses in a local assembly [ 14 , 15 , 16 ]. Previous studies have linked episodes of MW to oscillations at particular frequencies of neuronal activity in the brain.…”

Section: Introductionmentioning

confidence: 99%

Local Oscillatory Brain Dynamics of Mind Wandering in Schizophrenia

et al. 2021

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A number of studies have focused on brain dynamics underlying mind wandering (MW) states in healthy people. However, there is limited understanding of how the oscillatory dynamics accompanying MW states and task-focused states are characterized in clinical populations. In this study, we explored EEG local synchrony of MW associated with schizophrenia, under the premise that changes in attention that arise during MW are associated with a different pattern of brain activity. To this end, we measured the power of EEG oscillations in different frequency bands, recorded while participants watched short video clips. In the group of participants diagnosed with schizophrenia, the power in MW states was significantly lower than during task-focused states, mainly in the frontal and posterior regions. However, in the group of healthy controls, the differences in power between the task-focused and MW states occurred exclusively in the posterior region. Furthermore, the power of the frequency bands during MW and during episodes of task-focused attention correlated with cognitive variables such as processing speed and working memory. These findings on dynamic changes of local synchronization in different frequency bands and areas of the cortex can improve our understanding of mental disorders, such as schizophrenia.

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Consistency and dynamical changes of directional information flow in different brain states: A comparison of working memory and resting-state using EEG

Cited by 17 publications

References 62 publications

Transcranial stimulation of alpha oscillations up-regulates the default mode network

Transcranial stimulation of alpha oscillations up-regulates the default mode network

Theta mediated dynamics of human hippocampal-neocortical learning systems in memory formation and retrieval

Local Oscillatory Brain Dynamics of Mind Wandering in Schizophrenia

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