jean-marc Lina

École de Technologie Supérieure · PhysNum

Magnetoencephalography (MEG) is widely used for studying resting-state brain connectivity. However, MEG source imaging is ill posed and has limited spatial resolution. This introduces source-leakage issues, making it challenging to interpret MEG-derived connectivity in resting states. To address this, we validated MEG-derived connectivity from 45 h...

Purpose Study the scotopic oscillatory potentials (OPs) in mice over a wide range of flash luminance levels using the Hilbert transform (HT) to extract new features of the high frequency components of the electroretinogram (ERG). Methods Scotopic ERGs [Intensity: − 6.3 to 0.9 log cd∙s∙m⁻²; 12 h of dark-adaptation] were obtained from adult mice (C5...

Enhancing the retention of recent memory traces through sleep reactivation is possible via Targeted Memory Reactivation (TMR), involving cueing learned material during post-training sleep. Evidence indicates detectable short-term microstructural changes in the brain within an hour after motor sequence learning, and post-training sleep is believed t...

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. I...

Objective In addition to the oscillatory brain activity, the nonoscillatory (scale‐free) components of the background electroencephalogram (EEG) may provide further information about the complexity of the underlying neuronal network. As epilepsy is considered a network disease, such scale‐free metrics might help to delineate the epileptic network....

Simultaneous recording of electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) is a widely used non-invasive neuroimaging technique in sleep studies. However, EEG data are strongly influenced by two types of MRI-related artefacts: gradient artefacts (GA) and ballistocardiogram artefacts (BCG). If artefacts correction is sub...

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. The second identified the neuroa...

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 t...

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 bra...

Background Previous longitudinal studies have identified variability in compliance with COVID-19 preventive measures, noting the heightened sensitivity of the least compliant groups to situational factors like easing restrictions. However, they overlooked other forms of variability inherent in compliance behaviour. Hence, we investigated compliance...

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 sle...

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

The symptomatology of Alzheimer's disease (AD) includes cognitive deficits and sleep disturbances. Recent findings suggest the involvement of dysfunctions in lipid metabolism, such as oleic acid build-up, in the brain of AD patients and animal models. In addition, the inhibition of stearoyl-CoA desaturase (SCD), a lipid-converting enzyme, was shown...

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 presen...

Sleep plays a critical role in maintaining overall health and well‐being. During the early days of the COVID‐19 pandemic, reports showed a high prevalence of short sleep and poor sleep quality. This was associated with various health predictors. Given the lack of Canadian longitudinal studies and representative samples, our study aimed to (1) exami...

Electroencephalographic sleep stage transitions and altered first REM sleep period transitions have been identified as biomarkers of type 1 narcolepsy in adults, but not in children. Studies on memory complaints in narcolepsy have not yet investigated sleep-dependent memory consolidation. We aimed to explore stage transitions; more specifically alt...

Background: Clinical and neuroanatomical correlates of daytime sleepiness in Parkinson’s disease remain inconsistent in the literature. Objectives: Two studies were conducted. The first study evaluated the interrelation between non-motor and motor symptoms associated with daytime sleepiness in Parkinson’s disease. The second study identified the ne...

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 adhe...

In the context of public health crises such as the COVID‐19 pandemic, it is essential that individuals cooperate by complying with preventive measures (e.g., wearing a mask). The current research examines how high trust in close others is linked to less cooperation—that is, less compliance with measures—and thus, undermines collective interests. Sp...

Introduction Obstructive sleep apnea (OSA) is increasingly recognized as a risk factor for cognitive decline, and has been associated with structural brain alterations in regions relevant to memory processes and Alzheimer’s disease. However, it is unclear whether OSA is associated with disrupted functional connectivity (FC) patterns between these r...

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 (N = 3,613; 50.6% women) was sampled longitudinally over 11 waves (April 2020-April 2021), using...

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 va...

The sleep slow wave (SW) transition between negative and positive phases is thought to mirror synaptic strength and likely depends on brain health. This transition shows significant age-related changes but has not been investigated in pathological aging. The present study aimed at comparing the transition speed and other characteristics of SW betwe...

Background: Magnetoencephalography (MEG) is a widely used non-invasive tool to estimate brain activity with high temporal resolution. However, due to the ill-posed nature of the MEG source imaging (MSI) problem, the ability of MSI to identify accurately underlying brain sources along the cortical surface is still uncertain and requires validation....

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 trajec...

Study objectives The ability to generate slow waves (SW) during non-rapid eye movement (NREM) sleep decreases as early as the 5 th decade of life, predominantly over frontal regions. This decrease may concern prominently SW characterised by a fast switch from hyperpolarised to depolarised, or down-to-up, state. Yet, the relationship between these f...

Introduction: Simultaneous EEG-fMRI is a widely used non-invasive neuroimaging technique in sleep studies. However, EEG data are strongly influenced by two types of MRI-related artefacts (gradient artefacts: GA, ballistocardiogram artefacts: BCG). Particularly, the BCG obscures the EEG signals below 20Hz, and could make it difficult to investigate...

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 is a...

Sleep spindles (SS) are crucial to brain functions like memory and learning. SS characteristics result from the propagation of nerve impulses along white matter (WM) projections underlying an intricate loop between the thalamus and the cortex. SS amplitude and density have been associated with WM diffusion microarchitecture but physiological mechan...

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. In this study, the resting-state neuromag...

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 is a...

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 a...

Schizophrenia has a complex etiology and symptomatology that is difficult to untangle. After decades of research, important advancements towards 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. In this study, the resting-state neuroma...

Background Investigating the relationship between task-related hemodynamic responses and cortical excitability is challenging because it requires simultaneous measurement of hemodynamic responses while applying non-invasive brain stimulation. Moreover, cortical excitability and task-related hemodynamic responses are both associated with inter-/intr...

Background: The relationship between task-related hemodynamic activity and brain excitability is poorly understood in humans as it is technically challenging to combine simultaneously non-invasive brain stimulation and neuroimaging modalities. Cortical excitability corresponds to the readiness to become active and as such it may be linked to metabo...

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. Using the Transition frequency, slow waves with a slow transition...

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 optim...

Simultaneous recording of EEG and fMRI is a very promising non-invasive neuroimaging technique, providing a wide range of complementary information to characterize underlying mechanisms associated with brain functions. However, EEG data obtained from the simultaneous EEG-fMRI recordings are strongly influenced by MRI related artefacts, namely gradi...

Simultaneous recording of electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) is a very promising non-invasive neuroimaging technique. However, EEG data obtained from the simultaneous EEG–fMRI are strongly influenced by MRI-related artefacts, namely gradient artefacts (GA) and ballistocardiogram (BCG) artefacts. When compa...

Simultaneous recording of electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) is a very promising non-invasive neuroimaging technique. However, EEG data obtained from the simultaneous EEG–fMRI are strongly influenced by MRI-related artefacts, namely gradient artefacts (GA) and ballistocardiogram (BCG) artefacts. When compa...

Interactions between interictal epileptiform discharges (IEDs) and distant cortical regions subserve potential effects on cognition of patients with focal epilepsy. We hypothesize that “healthy” brain areas at a distance from the epileptic focus may respond to the interference of IEDs by generating inhibitory alpha and beta oscillations. We predict...

Introduction Approximately 50% (between 16–74%) of adults with Parkinson’s disease (PD) show excessive daytime sleepiness. Besides its important role for vision, light conveys a powerful stimulating signal for alertness and cognition. Recent research has demonstrated that the blue part of light spectrum is the most efficient in enhancing vigilance...

Goal: The full-field electroretinogram (ffERG) is an objective tool to assess global retinal function, though as it is currently done, it is unable to localize sources of retinal dysfunction or damage. To overcome this, we have developed a new way to record multiple spatial derivations of the ERG using the rotating capability of the eye, thus crea...

In functional near infrared spectroscopy (fNIRS), deconvolution analysis of oxy and deoxy-hemoglobin concentration changes allows estimating specific hemodynamic response functions (HRF) elicited by neuronal activity, taking advantage of the fNIRS excellent temporal resolution. Diffuse optical tomography (DOT) is also becoming the new standard reco...

Even though sleep modification is a hallmark of the aging process, age-related changes in functional connectivity using functional Magnetic Resonance Imaging (fMRI) during sleep, remain unknown. Here, we combined electroencephalography and fMRI to examine functional connectivity differences between wakefulness and light sleep stages (N1 and N2 stag...

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 (i.e., HbO/HbR) concentration changes within the cortical regions. In the pre...

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. Using the Transition frequency, slow waves with a slow transition...

Simultaneous recording of EEG and fMRI is a very promising non-invasive neuroimaging technique, providing a wide range of complementary information to characterize underlying mechanisms associated with brain functions. However, EEG data obtained from the simultaneous EEG-fMRI recordings are strongly influenced by MRI related artefacts, namely gradi...

Breathing rate (BR) is one of the vital signs used in physiological monitoring. Conventional BR monitoring requires attaching wired canula/thermistor on the buco-nasal area to measure air-flow, inducing discomfort to the subject. Abdominal/thoracic belts are also used to detect breathing movements whereas esophageal pressure is the gold standard to...

Aging is associated with reduced slow wave (SW) density (number SW/min in non-rapid-eye-movement sleep) and amplitude. It has been proposed that an age-related decrease in SW density may be due to a reduction in EEG amplitude instead of a decline in the capacity to generate SW. Here, we propose a data-driven approach to adapt SW amplitude criteria...

Idiopathic hypersomnia is a poorly defined nosological entity and has important phenotype heterogeneity. Moreover, diagnosing idiopathic hypersomnia is challenging as patients can report significant symptoms but may not meet diagnostic criteria on standard objective tests. Advanced analyses of electroencephalographic (EEG) activity could provide ob...

Sleep spindles are an essential part of non-rapid eye movement sleep, notably involved in sleep consolidation, cognition, learning, and memory. These oscillatory waves depend on an interaction loop between the thalamus and the cortex, which relies on a structural backbone of thalamo-cortical white matter tracts. It is still largely unknown if the b...

Objective: Magnetoencephalography source imaging (MSI) of interictal epileptiform discharges (IED) is a useful presurgical tool in the evaluation of drug-resistant frontal lobe epilepsy (FLE) patients. Yet, failures in MSI can arise related to artifacts and to interference of background activity. Independent component analysis (ICA) is a popular de...

Objectives The present study aimed at investigating changes in waking electroencephalography (EEG), most specifically regarding spectral power and functional connectivity, in middle-aged and older adults with OSA. We also explored whether changes in spectral power or functional connectivity are associated with polysomnographic characteristics and/o...

Introduction Brain topography modulates age-related changes in the human sleep electroencephalogram, which are linked with differences in integrity of specific cortical areas and may reflect local changes in sleep homeostasis. In mice, there is conflicting evidence regarding the topography of age-related changes for NREM and REM sleep. To disambigu...

Source localization of interictal epileptiform discharges (IEDs) is clinically useful in the presurgical workup of epilepsy patients. We aimed to compare the performance of four different distributed magnetic source imaging (dMSI) approaches: Minimum norm estimate (MNE), dynamic statistical parametric mapping (dSPM), standardized low‐resolution ele...

Objective. Focal epilepsy is a disorder affecting several brain networks; however, epilepsy surgery usually targets a restricted region, the so-called epileptic focus. There is a growing interest in embedding resting state (RS) connectivity analysis into pre-surgical workup. Approach. In this retrospective study, we analyzed Magnetoencephalography...

Study Objectives In young adults, sleep is associated with important changes in cerebral connectivity during the first cycle of non-rapid eye movement (NREM) sleep. Our study aimed to evaluate how electroencephalography (EEG) connectivity during sleep differs between young and older individuals, and across the sleep cycles. Methods We used imagina...