scholarly journals New approach of using cortico-cortical evoked potential for functional brain evaluation

2021 ◽  
Vol 23 (2) ◽  
pp. 69-81
Author(s):  
Hyunjin Jo ◽  
Dongyeop Kim ◽  
Jooyeon Song ◽  
Dae-Won Seo
Keyword(s):  
Evoked Potential ◽  
Cortical Excitability ◽  
Effective Connectivity ◽  
Single Pulse ◽  
Brain Network ◽  
Delayed Response ◽  
Epileptogenic Zone ◽  
New Paradigm ◽  
Brain Connectome ◽  
The Brain

Cortico-cortical evoked potential (CCEP) mapping is a rapidly developing method for visualizing the brain network and estimating cortical excitability. The CCEP comprises the early N1 component the occurs at 10-30 ms poststimulation, indicating anatomic connectivity, and the late N2 component that appears at < 200 ms poststimulation, suggesting long-lasting effective connectivity. A later component at 200-1,000 ms poststimulation can also appear as a delayed response in some studied areas. Such delayed responses occur in areas with changed excitability, such as an epileptogenic zone. CCEP mapping has been used to examine the brain connections causally in functional systems such as the language, auditory, and visual systems as well as in anatomic regions including the frontoparietal neocortices and hippocampal limbic areas. Task-based CCEPs can be used to measure behavior. In addition to evaluations of the brain connectome, single-pulse electrical stimulation (SPES) can reflect cortical excitability, and so it could be used to predict a seizure onset zone. CCEP brain mapping and SPES investigations could be applied both extraoperatively and intraoperatively. These underused electrophysiologic tools in basic and clinical neuroscience might be powerful methods for providing insight into measures of brain connectivity and dynamics. Analyses of CCEPs might enable us to identify causal relationships between brain areas during cortical processing, and to develop a new paradigm of effective therapeutic neuromodulation in the future.

scholarly journals Local and Distant responses to single pulse electrical stimulation reflect different forms of connectivity

2020 ◽  
Author(s):  
Britni Crocker ◽  
Lauren Ostrowski ◽  
Ziv M. Williams ◽  
Darin D. Dougherty ◽  
Emad N. Eskandar ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Resting State ◽  
Diffusion Tensor ◽  
Effective Connectivity ◽  
Clinical Care ◽  
Structural Connectivity ◽  
Intractable Epilepsy ◽  
Single Pulse ◽  
Intracranial Electrode ◽  
The Brain

AbstractBackgroundMeasuring connectivity in the human brain can involve innumerable approaches using both noninvasive (fMRI, EEG) and invasive (intracranial EEG or iEEG) recording modalities, including the use of external probing stimuli, such as direct electrical stimulation.Objective/HypothesisTo examine how different measures of connectivity correlate with one another, we compared ‘passive’ measures of connectivity during resting state conditions map to the more ‘active’ probing measures of connectivity with single pulse electrical stimulation (SPES).MethodsWe measured the network engagement and spread of the cortico-cortico evoked potential (CCEP) induced by SPES at 53 total sites across the brain, including cortical and subcortical regions, in patients with intractable epilepsy (N=11) who were undergoing intracranial recordings as a part of their clinical care for identifying seizure onset zones. We compared the CCEP network to functional, effective, and structural measures of connectivity during a resting state in each patient. Functional and effective connectivity measures included correlation or Granger causality measures applied to stereoEEG (sEEGs) recordings. Structural connectivity was derived from diffusion tensor imaging (DTI) acquired before intracranial electrode implant and monitoring (N=8).ResultsThe CCEP network was most similar to the resting state voltage correlation network in channels near to the stimulation location. In contrast, the distant CCEP network was most similar to the DTI network. Other connectivity measures were not as similar to the CCEP network.ConclusionsThese results demonstrate that different connectivity measures, including those derived from active stimulation-based probing, measure different, complementary aspects of regional interrelationships in the brain.

scholarly journals Is Brain Connectome Research the Future Frontier for Subjective Cognitive Decline? A Systematic Review

2019 ◽  
Author(s):  
Ioulietta Lazarou ◽  
Spiros Nikolopoulos ◽  
Stavros Dimitriadis ◽  
Ioannis Kompatsiaris ◽  
Martha Spylioti ◽  
...  
Keyword(s):  
Systematic Review ◽  
White Matter ◽  
Cognitive Decline ◽  
Brain Network ◽  
Subjective Cognitive Decline ◽  
Research Activity ◽  
Brain Connectome ◽  
Advanced Stages ◽  
Multiple Network ◽  
The Brain

Objective: We performed a systematic literature review on Subjective Cognitive Decline (SCD) in order to examine whether the resemblance of brain connectome and functional connectivity (FC) alterations in SCD with respect to MCI, AD and HC can help us draw conclusions on the progression of SCD to more advanced stages of dementia.Methods: We searched for studies that used any neuroimaging tool to investigate potential differences of brain connectome in SCD with respect to HC, MCI, and AD.Results: Sixteen studies were finally included in the review. Apparent FC connections and disruptions were observed in the white matter, default mode and gray matter networks in SCD with regards to HC, MCI, and AD. Interestingly, more apparent connections in SCD were located over the posterior regions, while an increase of FC over anterior regions was observed as the disease progressed. Conclusions: Elders with SCD present a significant disruption of the brain network, which in most of the cases is worse than HC across multiple network parameters. Significance: The present review provides comprehensive and balanced coverage of a timely target research activity around SCD and the design of network-based biomarkers for the accurate detection of SCD.

scholarly journals Transcranial static magnetic stimulation over the motor cortex can facilitate the contralateral cortical excitability in human

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yasuyuki Takamatsu ◽  
Satoko Koganemaru ◽  
Tatsunori Watanabe ◽  
Sumiya Shibata ◽  
Yoshihiro Yukawa ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Magnetic Stimulation ◽  
Primary Motor Cortex ◽  
Cortical Excitability ◽  
Motor Evoked Potentials ◽  
Single Pulse ◽  
Brain Network ◽  
Corticospinal Excitability ◽  
Double Blind ◽  
The Right

AbstractTranscranial static magnetic stimulation (tSMS) has been focused as a new non-invasive brain stimulation, which can suppress the human cortical excitability just below the magnet. However, the non-regional effects of tSMS via brain network have been rarely studied so far. We investigated whether tSMS over the left primary motor cortex (M1) can facilitate the right M1 in healthy subjects, based on the hypothesis that the functional suppression of M1 can cause the paradoxical functional facilitation of the contralateral M1 via the reduction of interhemispheric inhibition (IHI) between the bilateral M1. This study was double-blind crossover trial. We measured the corticospinal excitability in both M1 and IHI from the left to right M1 by recording motor evoked potentials from first dorsal interosseous muscles using single-pulse and paired-pulse transcranial magnetic stimulation before and after the tSMS intervention for 30 min. We found that the corticospinal excitability of the left M1 decreased, while that of the right M1 increased after tSMS. Moreover, the evaluation of IHI revealed the reduced inhibition from the left to the right M1. Our findings provide new insights on the mechanistic understanding of neuromodulatory effects of tSMS in human.

Dynamics of Epileptiform Discharges Induced by Transcranial Magnetic Stimulation in Genetic Generalized Epilepsy

2017 ◽  
Vol 27 (07) ◽  
pp. 1750037 ◽  
Author(s):  
Dimitris Kugiumtzis ◽  
Christos Koutlis ◽  
Alkiviadis Tsimpiris ◽  
Vasilios K. Kimiskidis
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Magnetic Stimulation ◽  
Brain Connectivity ◽  
Effective Connectivity ◽  
Brain Network ◽  
Brain State ◽  
Epileptiform Discharges ◽  
Eeg Recordings ◽  
Generalized Epilepsy ◽  
The Brain

Objective: In patients with Genetic Generalized Epilepsy (GGE), transcranial magnetic stimulation (TMS) can induce epileptiform discharges (EDs) of varying duration. We hypothesized that (a) the ED duration is determined by the dynamic states of critical network nodes (brain areas) at the early post-TMS period, and (b) brain connectivity changes before, during and after the ED, as well as within the ED. Methods: EEG recordings from two GGE patients were analyzed. For hypothesis (a), the characteristics of the brain dynamics at the early ED stage are measured with univariate and multivariate EEG measures and the dependence of the ED duration on these measures is evaluated. For hypothesis (b), effective connectivity measures are combined with network indices so as to quantify the brain network characteristics and identify changes in brain connectivity. Results: A number of measures combined with specific channels computed on the first EEG segment post-TMS correlate with the ED duration. In addition, brain connectivity is altered from pre-ED to ED and post-ED and statistically significant changes were also detected across stages within the ED. Conclusion: ED duration is not purely stochastic, but depends on the dynamics of the post-TMS brain state. The brain network dynamics is significantly altered in the course of EDs.

scholarly journals Increased cortical excitability and reduced brain response propagation during attentional lapses

2020 ◽  
Author(s):  
Paolo Cardone ◽  
Maxime Van Egroo ◽  
Daphne Chylinski ◽  
Justinas Narbutas ◽  
Giulia Gaggioni ◽  
...  
Keyword(s):  
Cortical Excitability ◽  
Effective Connectivity ◽  
Age Groups ◽  
Real Life ◽  
List Type ◽  
Older Individuals ◽  
Brain Response ◽  
Attentional Lapses ◽  
Response Propagation ◽  
The Brain

AbstractModern lifestyle curtails sleep and increases nighttime work and leisure activities. This has a deleterious impact on vigilance and attention, exacerbating chances of committing attentional lapses, with potential dramatic outcomes. A full characterization of the brain mechanisms associated with lapses is still lacking. Here, we investigated the brain signature of attentional lapses and assessed whether cortical excitability and brain response propagation were modified during lapses and whether these modifications changed with aging. We compared electroencephalogram (EEG) responses to transcranial magnetic stimulation (TMS) during lapse and no-lapse periods while performing a continuous attentional/vigilance task at night, after usual bedtime. Data were collected in healthy younger (N=12; 18-30 y) and older individuals (N=12; 50-70 y) of both sexes. Amplitude and slope of the first component of the TMS-Evoked Potential (TEP) and Response Scattering (ReSc) were used to assess cortical excitability and brain response propagation, respectively. In line with our predictions, TEP during lapses was characterized by larger amplitude and slope. We further found that ReSc over the cortical surface was lower during lapses. Importantly, cortical excitability increase and response propagation decrease during lapse did not significantly differ between age groups. These results demonstrate that attentional lapses are associated with transient increase of excitability, and decrease in response propagation and effective connectivity. This pattern is similar to what is observed during sleep, suggesting that lapses reflect a sleep-like phenomenon. These findings could contribute to develop models aimed to predicting and preventing lapses in real life situations.HighlightsCortical excitability increases during attentional lapsesBrain response propagation is reduced during attentional lapsesAging does not affect the differences between normal attention and lapse periodsLapses characteristics resemble previous reports made during sleep

scholarly journals The Brain Network Underlying Serial Visual Search: Comparing Overt and Covert Spatial Orienting, for Activations and for Effective Connectivity

2009 ◽  
Vol 19 (12) ◽  
pp. 2946-2958 ◽  
Author(s):  
S. L. Fairhall ◽  
I. Indovina ◽  
J. Driver ◽  
E. Macaluso
Keyword(s):  
Visual Search ◽  
Effective Connectivity ◽  
Brain Network ◽  
Spatial Orienting ◽  
The Brain

scholarly journals Miswiring the brain: Human prenatal Δ9-tetrahydrocannabinol use associated with altered fetal hippocampal brain network connectivity

2021 ◽  
pp. 101000
Author(s):  
Moriah E. Thomason ◽  
Ava C. Palopoli ◽  
Nicki N. Jariwala ◽  
Denise M. Werchan ◽  
Alan Chen ◽  
...  
Keyword(s):  
Network Connectivity ◽  
Brain Network ◽  
Brain Network Connectivity ◽  
The Brain
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