Valentin Ourry

McGill University | McGill · Department of Psychiatry

Engagement in cognitive activity (CA) and physical activity (PA) during the lifespan may counteract brain atrophy later in life. Here, we investigated engagement in CA and PA during late adulthood in association with gray matter volume (GM) in normal older adults, with special focus on the hippocampus. Forty-five cognitively normal older individual...

Importance Increasing evidence suggests that sleep-disordered breathing (SDB) increases the risk of developing Alzheimer clinical syndrome. However, the brain mechanisms underlying the link between SDB and Alzheimer disease are still unclear. Objective To determine which brain changes are associated with the presence of SDB in older individuals wh...

Background As the population ages, maintaining mental health and well-being of older adults is a public health priority. Beyond objective measures of health, self-perceived quality of life (QoL) is a good indicator of successful aging. In older adults, it has been shown that QoL is related to structural brain changes. However, QoL is a multi-facete...

Background: The Lifetime of Experiences Questionnaire (LEQ) assesses complex mental activity across the life-course and has been associated with brain and cognitive health. The different education systems and occupation classifications across countries represent a challenge for international comparisons. The objectives of this study were four-fold:...

Medial temporal lobe (MTL) atrophy is a key feature of Alzheimer's disease (AD), however, it also occurs in typical aging. To enhance the clinical utility of this biomarker, we need to better understand the differential effects of age and AD by encompassing the full AD-continuum from cognitively unimpaired (CU) to dementia, including all MTL subreg...

Epidemiological studies show that modifiable risk factors account for about 40% of the population variability in risk of developing dementia, including sporadic Alzheimer's disease (sAD). Recent findings suggest that these factors might also modify disease trajectories of people with autosomal dominant Alzheimer's disease (ADAD). With positron emis...

Background and objectives Sleep-disordered breathing (SDB) has been related to amyloid deposition and increased dementia risk. However, how SDB relates to medial temporal lobe neurodegeneration and subsequent episodic memory impairment is unclear. Our objective was to investigate the impact of amyloid positivity on the associations between SDB seve...

Objective: Rapid-eye-movement (REM) sleep is markedly altered in Alzheimer's disease (AD), and its reduction in older populations is associated with AD risk. However, little is known about the underlying brain mechanisms. Our objective was to investigate the relationships between REM sleep integrity and amyloid deposition, grey matter volume and p...

Basic emotional functions seem well preserved in older adults. However, their reactivity to and recovery from socially negative events remain poorly characterized. To address this, we designed a ‘task–rest’ paradigm in which 182 participants from two independent experiments underwent functional magnetic resonance imaging while exposed to socio-emot...

Sleep plays a crucial role in memory consolidation. Recent data in rodents and young adults revealed that fast spindle band power fluctuates at a 0.02-Hz infraslow scale during non-rapid eye movement (NREM) sleep. These fluctuations result from a periodic temporal clustering of spindles and may modulate sleep maintenance and memory consolidation. W...

Subclinical depressive symptoms are associated with increased risk of Alzheimer’s disease (AD), but the brain mechanisms underlying this relationship are still unclear. We aimed to provide a comprehensive overview of the brain substrates of subclinical depressive symptoms in cognitively unimpaired older adults using complementary multimodal neuroim...

Importance: No lifestyle-based randomized clinical trial directly targets psychoaffective risk factors of dementia. Meditation practices recently emerged as a promising mental training exercise to foster brain health and reduce dementia risk. Objective: To investigate the effects of meditation training on brain integrity in older adults. Design...

Background Older individuals with subjective cognitive decline (SCD) perceive that their cognition has declined but do not show objective impairment on neuropsychological tests. Individuals with SCD are at elevated risk of objective cognitive decline and incident dementia. Non-pharmacological interventions (including mindfulness-based and health se...

Background: This study assesses the relationships between dynamic functional network connectivity (DFNC) and dementia risk. Methods: DFNC of the default mode (DMN), salience (SN), and executive control networks was assessed in 127 cognitively unimpaired older adults. Stepwise regressions were performed with dementia risk and protective factors a...

Introduction: Physical inactivity and female sex are independently associated with increased Alzheimer's disease (AD) lifetime risk. This study investigates the possible interactions between sex and physical activity on neuroimaging biomarkers. Methods: In 134 cognitively unimpaired older adults (≥65 years, 82 women) from the Age-Well randomized...

Objectif De récentes études ont mis en évidence chez le rongeur et de jeunes adultes un regroupement périodique des fuseaux de sommeil en trains, responsables d’une fluctuation de la puissance spectrale sigma avec une périodicité de ∼50s durant le sommeil NREM. Nous étudions ici ces aspects dynamiques des fuseaux chez le sujet âgé et leur lien avec...

Objectives Deepening our understanding of the mechanisms by which meditation practices impact well-being and human flourishing is essential for advancing the science of meditation. A recent phenomenologically grounded classification system distinguishes attentional, constructive, and deconstructive forms of meditation based on the psychological mec...

L’un des défis majeurs de la société est de maintenir la population croissante de personnes âgées en bonne santé en les préservant du déclin cognitif et des risques de développer une maladie d’Alzheimer. Maintenir la qualité de vie et du sommeil, qui diminuent avec l’âge, est également essentiel pour atteindre ce vieillissement en bonne santé. L’ob...

Background Sleep‐dependent memory consolidation, which is thought to rely on the dialogue between the hippocampus and the medial prefrontal cortex (mPFC) during NREM sleep, is mediated by slow waves (SW) and sleep spindles. Some studies indicate that this process is impaired in ageing but also in sleep‐disordered breathing (SDB), a very common slee...

Background Subclinical depressive symptoms are prevalent in older adults. They are associated with increased risk for both clinical depression and Alzheimer’s disease (AD), and may at least partly reflect early AD manifestations. However, the brain mechanisms underlying the relationship between depressive symptoms and AD remain to be elucidated. Th...

Sleep, especially slow wave sleep (SWS), favors efficient cognitive functioning. This effect may be impaired in aging, but might be modulated by cognitive reserve. Indeed, a study reported that highly educated older adults were able to better tolerate the negative effects of subjective sleep disturbances on verbal fluency scores. Growing evidence a...

Background Physical inactivity in older adults has been linked to an increased risk of dementia. On the other hand, increasing evidence indicates that sex is likely to influence Alzheimer’s disease (AD) pathophysiology, leading to a differential susceptibility to the disease in women versus men. We propose to investigate the interplay between sex a...

Background The Lifetime of Experiences questionnaire (LEQ, Valenzuela and Sachdev, 2007) is an instrument that comprehensively assesses mental activity (education/occupation and leisure activities) across the lifespan (13‐30, 30‐65, 65‐present). The LEQ has been associated with brain health outcomes and cognitive decline. Challenges for the use of...

Introduction Subjectively experienced cognitive decline in older adults is an indicator of increased risk for dementia and is also associated with increased levels of anxiety symptoms. As anxiety is itself emerging as a risk factor for cognitive decline and dementia, the primary question of the present study is whether an 8-week mindfulness-based i...

Background. There is increased recognition of the relevance of subjective feeling and self-perception in preclinical Alzheimer’s disease (AD). For example, loneliness has recently been related to higher amyloid burden in cognitively normal older adults. Another important factor might be self-perceived quality of life (QoL) known to be related to ne...

La qualité de vie (Qdv) représente la perception subjective des conditions de vie de l’individu, reflétant son bien-être et englobant de manière complexe la santé physique de la personne, son état psychologique, ses relations sociales et sa relation avec les spécificités de son environnement. La QdV a un impact important sur la santé mentale et phy...