Publications by authors named "Jean-Marc Lina"

Previous studies indicate differences in experiences of loneliness during the COVID-19 pandemic but are constricted by limited timeframes and absence of key risk factors. This study explores temporal and inter-individual variations of loneliness in Canadians over the pandemic's first year (April 2020-2021), by identifying loneliness trajectories. It then seeks to provide information about groups overrepresented in high and persistent loneliness trajectories by examining their associations with risk factors: social isolation indicators (living alone, adherence to health measures limiting in-person contacts, and online contacts), young adultood, and the interactions between these factors.

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  • This study investigates both oscillatory and nonoscillatory components of intracranial EEG in adults with drug-resistant epilepsy to better understand the complexity of the neuronal network affected by the condition.
  • Results show distinct differences in sleep oscillatory metrics, such as a reduction in spindle activity and an increase in rhythmic gamma power, which could have implications for identifying the epileptogenic zone.
  • The research highlights the potential of using nonoscillatory metrics, particularly the H exponent, as effective predictors of surgical outcomes in patients undergoing epilepsy surgery.
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Clinical and neuroanatomical correlates of daytime sleepiness in Parkinson's disease (PD) remain inconsistent in the literature. Two studies were conducted here. The first evaluated the interrelation between non-motor and motor symptoms, using a principal component analysis, associated with daytime sleepiness in PD.

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Electro/Magneto-EncephaloGraphy (EEG/MEG) source imaging (EMSI) of epileptic activity from deep generators is often challenging due to the higher sensitivity of EEG/MEG to superficial regions and to the spatial configuration of subcortical structures. We previously demonstrated the ability of the coherent Maximum Entropy on the Mean (cMEM) method to accurately localize the superficial cortical generators and their spatial extent. Here, we propose a depth-weighted adaptation of cMEM to localize deep generators more accurately.

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Sleep slow waves are the hallmark of deeper non-rapid eye movement sleep. It is generally assumed that gray matter properties predict slow-wave density, morphology, and spectral power in healthy adults. Here, we tested the association between gray matter volume (GMV) and slow-wave characteristics in 27 patients with moderate-to-severe traumatic brain injury (TBI, 32.

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While commonly treated as a uniform state in practice, rapid eye movement sleep contains two distinct microstructures-phasic (presence of rapid eye movement) and tonic (no rapid eye movement). This study aims to identify technical challenges during rapid eye movement sleep microstructure visual classification in patients with rapid eye movement sleep behaviour disorder, and to propose solutions to enhance reliability between scorers. Fifty-seven sleep recordings were randomly allocated into three subsequent batches (n = 10, 13 and 34) for scoring.

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Study Objectives: Idiopathic/isolated rapid eye movement-sleep behavior disorder (iRBD) often precedes the onset of synucleinopathies. Here, we investigated whether baseline resting-state EEG advanced spectral power and functional connectivity differed between iRBD patients who converted towards a synucleinopathy at follow-up and those who did not.

Methods: Eighty-one participants with iRBD (66.

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The COVID-19 pandemic has produced unprecedented changes in the lives of many people. Although research has documented associations between concerns related to COVID-19 and poor mental health indicators, fewer studies have focused on positive factors that could help people better cope with this stressful social context. To fill this gap, the present research investigated the trajectories of self-compassion facets in times of dramatic social change.

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  • Electroencephalographic sleep transitions in children with narcolepsy-cataplexy show similar characteristics to those observed in adults, indicating potential biomarkers for diagnosis.
  • The study found that children with narcolepsy experienced significantly higher overnight transition rates and altered REM sleep transitions, which correlated with lower sleep-dependent memory consolidation scores.
  • Further research is necessary to validate these findings and explore biomarkers across a larger sample, including various types of narcolepsy and other sleep disorders.
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Previous studies have highlighted the importance of promoting health literacy and minimizing misinformation to encourage higher adherence to key public health measures during the COVID-19 pandemic. This study explores how one's self-reported understanding of information and types of sources used to get information regarding COVID-19 can hinder adherence to public health measures implemented by the Canadian government. Data was collected following a longitudinal design of 11 time points for April 2020 to April 2021.

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  • Obstructive sleep apnea (OSA) is linked to cognitive decline and may affect functional connectivity (FC) between brain regions important for memory, particularly in older adults.
  • Ninety-four participants underwent sleep assessments and neuropsychological tests to examine how OSA severity correlates with FC between the default mode network and medial temporal lobe regions, with results controlled for age, sex, and education.
  • The study found that higher OSA severity measured by the apnea-hypopnea index is associated with reduced FC in specific brain areas, but these patterns did not correlate with oxygen desaturation or micro-arousal indices, and differences were noted based on cognitive status (MCI vs. unimpaired).
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  • MEG is a non-invasive tool used to estimate brain activity but its accuracy in identifying cortical sources is uncertain and needs validation.
  • The study compared MEG source imaging with an iEEG atlas to assess resting state activity in healthy participants, using wavelet-based techniques and virtual iEEG potentials for quantitative analysis.
  • Results showed that MEG performed better in lateral brain regions and highlighted overestimations in the alpha band, suggesting that while MEG provides valuable insights, its measurements may not always match those from more invasive iEEG techniques.
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We report the design and testing of a sensor pad based on optical and flexible materials for the development of pressure monitoring devices. This project aims to create a flexible and low-cost pressure sensor based on a two-dimensional grid of plastic optical fibers embedded in a pad of flexible and stretchable polydimethylsiloxane (PDMS). The opposite ends of each fiber are connected to an LED and a photodiode, respectively, to excite and measure light intensity changes due to the local bending of the pressure points on the PDMS pad.

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Introduction: We investigated whether initial risk classes and heterogeneous trajectories of self-compassion over the course of the pandemic may impact well-being outcomes 1 year into the pandemic.

Methods: A large, representative sample of Canadians ( = 3,613; 50.6% women) was sampled longitudinally over 11 waves (April 2020-April 2021), using a rolling cross-sectional survey design.

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Objectives: Previous studies found a general increase in prejudice against Chinese people during the first months of the pandemic. The present study aims to consider inter-individual heterogeneity in stability and change regarding prejudice involving Chinese people during the pandemic. The first objective is to identify and describe different trajectories of prejudice over a seven-month period during the pandemic.

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Investigating the relationship between task-related hemodynamic responses and cortical excitability is challenging because it requires simultaneous measurement of hemodynamic responses while applying noninvasive brain stimulation. Moreover, cortical excitability and task-related hemodynamic responses are both associated with inter-/intra-subject variability. To reliably assess such a relationship, we applied hierarchical Bayesian modeling.

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  • The study investigates the differences in sleep slow-wave (SW) transition between older adults with amnestic mild cognitive impairment (aMCI) and cognitively normal (CN) controls, focusing on the impact of obstructive sleep apnea (OSA).
  • Findings reveal that those with aMCI exhibit a slower transition speed between negative and positive SW phases, which correlates with cognitive decline and memory issues, while CN participants show improvements.
  • The results suggest that changes in SW metrics may reflect synaptic health, prompting future research to examine their relationship with biomarkers of synaptic integrity, particularly in the context of pathological aging.
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The electroretinogram (ERG) represents the biopotential evoked by the retina in response to a light stimulus. The flash evoked ERG (fERG) is the ERG modality most frequently used clinically to diagnose and monitor retinal disorders. We hereby present a new method to record spontaneous retinal activity, without the use of a flash stimulus, that we named the resting-state ERG (rsERG).

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Study Objectives: The ability to generate slow waves (SW) during non-rapid eye movement (NREM) sleep decreases as early as the 5th decade of life, predominantly over frontal regions. This decrease may concern prominently SW characterized by a fast switch from hyperpolarized to depolarized, or down-to-up, state. Yet, the relationship between these fast and slow switcher SW and cerebral microstructure in ageing is not established.

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Sleep alteration is a hallmark of ageing and emerges as a risk factor for Alzheimer's disease (AD). While the fine-tuned coalescence of sleep microstructure elements may influence age-related cognitive trajectories, its association with AD processes is not fully established. Here, we investigated whether the coupling of spindles and slow waves (SW) is associated with early amyloid-β (Aβ) brain burden, a hallmark of AD neuropathology, and cognitive change over 2 years in 100 healthy individuals in late-midlife (50-70 years; 68 women).

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Schizophrenia has a complex etiology and symptomatology that is difficult to untangle. After decades of research, important advancements toward a central biomarker are still lacking. One of the missing pieces is a better understanding of how non-linear neural dynamics are altered in this patient population.

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Functional near-infrared spectroscopy (fNIRS) measures the hemoglobin concentration changes associated with neuronal activity. Diffuse optical tomography (DOT) consists of reconstructing the optical density changes measured from scalp channels to the oxy-/deoxy-hemoglobin concentration changes within the cortical regions. In the present study, we adapted a nonlinear source localization method developed and validated in the context of Electro- and Magneto-Encephalography (EEG/MEG): the Maximum Entropy on the Mean (MEM), to solve the inverse problem of DOT reconstruction.

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Sleep slow waves are studied for their role in brain plasticity, homeostatic regulation, and their changes during aging. Here, we address the possibility that two types of slow waves co-exist in humans. Thirty young and 29 older adults underwent a night of polysomnographic recordings.

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In the present study, we proposed and evaluated a workflow of personalized near infra-red optical tomography (NIROT) using functional near-infrared spectroscopy (fNIRS) for spatiotemporal imaging of cortical hemodynamic fluctuations. The proposed workflow from fNIRS data acquisition to local 3D reconstruction consists of: (a) the personalized optimal montage maximizing fNIRS channel sensitivity to a predefined targeted brain region; (b) the optimized fNIRS data acquisition involving installation of optodes and digitalization of their positions using a neuronavigation system; and (c) the 3D local reconstruction using maximum entropy on the mean (MEM) to accurately estimate the location and spatial extent of fNIRS hemodynamic fluctuations along the cortical surface. The workflow was evaluated on finger-tapping fNIRS data acquired from 10 healthy subjects for whom we estimated the reconstructed NIROT spatiotemporal images and compared with functional magnetic resonance imaging (fMRI) results from the same individuals.

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