Publications of Julien Ly
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See detailCortical excitability transiently increases during attentional lapses
Cardone, Paolo ULiege; Gaggioni, Giulia ULiege; Van Egroo, Maxime ULiege et al

Poster (2019)

It is well established that conscious state modulates cortical excitability, such that wakefulness has lower excitability compared to sleep. However, the impact of conscious content on cortical ... [more ▼]

It is well established that conscious state modulates cortical excitability, such that wakefulness has lower excitability compared to sleep. However, the impact of conscious content on cortical excitability has mostly been neglected in previous research: one can indeed be conscious without being truly aware of an external stimulus, for instance, during vigilance lapses. Here, we hypothesized that, during a vigilance lapse, the brain reacts to stimuli in a similar way to when it is unconscious. To test this hypothesis, cortical excitability was investigated while performing a continuous vigilance task (Compensatory Tracking Task, CTT) after prolonged wakefulness beyond habitual sleep time. Cortical excitability changes between periods with and without vigilance lapses were inferred from amplitude, slope and peak latencies of the first component of the TMS-evoked EEG potential (TEP; 0–30 ms post-TMS). During lapses vs. no-lapses, we found a significant amplitude increases of TEP and a concomitant significant increase in the latency of TEP positive peak. These results suggest that there is a transient change of cortical excitability during vigilance lapses, pointing to an alteration of the brain similar to the one observed during unconscious states, such as during sleep. Future research should investigate how these changes interfere with sensory processing and cognition and their molecular mechanisms. These findings provide new insight into the brain mechanisms underlying changes in consciousness content and in transient alteration of attention. [less ▲]

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See detailHuman fronto-parietal response scattering subserves vigilance at night.
Gaggioni, Giulia ULiege; LY, Julien ULiege; Chellappa, Sarah et al

in NeuroImage (2018)

Detailed reference viewed: 56 (17 ULiège)
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See detailCircadian dynamics in measures of cortical excitation and inhibition balance
Chellappa, Sarah; Gaggioni, Giulia ULiege; LY, Julien ULiege et al

in Scientific Reports (2016), 6:33661

Detailed reference viewed: 69 (19 ULiège)
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See detailCircadian regulation of human cortical excitability
LY, Julien ULiege; Gaggioni, Giulia ULiege; Chellappa, Sarah et al

in Nature Communications (2016)

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See detailA finite-element reciprocity solution for EEG forward modeling with realistic individual head models
Ziegler, Erik ULiege; Chellappa, Sarah Laxhmi ULiege; Gaggioni, Giulia ULiege et al

in NeuroImage (2014), 103

Highlights • Creates EEG forward models suitable for high-resolution source localization. • Automatic T1-based whole-head finite element meshing and leadfield computation. • Pipelines can incorporate ... [more ▼]

Highlights • Creates EEG forward models suitable for high-resolution source localization. • Automatic T1-based whole-head finite element meshing and leadfield computation. • Pipelines can incorporate conductivity tensors from diffusion-weighted images. • Open-source toolbox shared under a permissive software license. • Accuracy comparable to SimBio FEM and superior to OpenMEEG BEM solutions. [less ▲]

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See detailHuman cortical excitability depends on time spent awake and circadian phase
Ly, Julien ULiege; Gaggioni, Giulia ULiege; Chellappa, Sarah Laxhmi ULiege et al

Scientific conference (2014, October 04)

At any point in time, human performance results from the interaction of two main factors: a circadian signal varying with the time of the day and the sleep need accrued throughout the preceding waking ... [more ▼]

At any point in time, human performance results from the interaction of two main factors: a circadian signal varying with the time of the day and the sleep need accrued throughout the preceding waking period. But what’s happen at the cortical cerebral level? We used a novel technique coupling transcranial magnetic stimulation with electroencephalography (TMS/EEG) to assess the influence of time spent awake and circadian phasis on human cortical excitability. Twenty-two healthy young men underwent 8 TMS/EEG sessions during a 28 hour sleep deprivation protocole. We found that cortical excitability depends on both time spent awake and circadian phasis. [less ▲]

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See detailHuman cortical excitability depends on time spent awake and circadian phase
Ly, Julien ULiege; Chellappa, Sarah Laxhmi ULiege; Gaggioni, Giulia ULiege et al

Conference (2014, September 17)

At any point in time, human performance results from the interaction of two main factors: a circadian signal varying with the time of the day and the sleep need accrued throughout the preceding waking ... [more ▼]

At any point in time, human performance results from the interaction of two main factors: a circadian signal varying with the time of the day and the sleep need accrued throughout the preceding waking period. But what’s happen at the cortical cerebral level? We used a novel technique coupling transcranial magnetic stimulation with electroencephalography (TMS/EEG) to assess the influence of time spent awake and circadian phasis on human cortical excitability. Twenty-two healthy young men underwent 8 TMS/EEG sessions during a 28 hour sleep deprivation protocole. We found that cortical excitability depends on both time spent awake and circadian phasis. [less ▲]

Detailed reference viewed: 61 (18 ULiège)
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See detailHuman cortical excitability depends on time awake and circadian phase
Ly, Julien ULiege; Chellappa, Sarah Laxhmi ULiege; Gaggioni, Giulia ULiege et al

Conference (2014, September 17)

At any point in time, human performance results from the interaction of two main factors: a circadian signal varying with the time of the day and the sleep need accrued throughout the preceding waking ... [more ▼]

At any point in time, human performance results from the interaction of two main factors: a circadian signal varying with the time of the day and the sleep need accrued throughout the preceding waking period. But what’s happen at the cortical cerebral level? We used a novel technique coupling transcranial magnetic stimulation with electroencephalography (TMS/EEG) to assess the influence of time spent awake and circadian phasis on human cortical excitability. Twenty-two healthy young men underwent 8 TMS/EEG sessions during a 28 hour sleep deprivation protocole. We found that cortical excitability depends on both time spent awake and circadian phasis. [less ▲]

Detailed reference viewed: 74 (15 ULiège)
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See detailAutomatic biorythms description from actigraphic data
González y Viagas, Miguel ULiege; Ly, Julien ULiege; Gaggioni, Giulia ULiege et al

Poster (2014, September)

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See detailCortical excitability dynamics of during sleep deprivation set PVT performance
Borsu, Chloé; Gaggioni, Giulia ULiege; Ly, Julien ULiege et al

Poster (2014, September)

Detailed reference viewed: 43 (10 ULiège)
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See detailPhotic memory for executive brain responses
Chellappa*, Sarah Laxhmi ULiege; Ly*, Julien ULiege; Meyer, Christelle ULiege et al

in Proceedings of the National Academy of Sciences of the United States of America (2014), Epub ahead of print

Detailed reference viewed: 158 (22 ULiège)
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See detailMelanopsin bistability impinges on higher order cognitive brain function
Chellappa, Sarah Laxhmi ULiege; Ly, Julien ULiege; Meyer, Christelle ULiege et al

in Sleep (2013), 36(Suppl. 1),

Detailed reference viewed: 97 (6 ULiège)