Author name cluster

Julie Carrier

Possible papers associated with this exact author name in Arrow. This page groups case-insensitive exact name matches and is not a full identity disambiguation profile.

6 papers

1 author row

YNICL Journal 2025 Journal Article

Sleep spindle density and morphology are resilient to post-traumatic gray matter volume loss

Narges Kalantari
Véronique Daneault
Hélène Blais
Claire André
Erlan Sanchez
Jean-Marc Lina
Caroline Arbour
Danielle Gilbert

Moderate to severe traumatic brain injury (TBI) leads to gray matter volume (GMV) loss, cognitive dysfunction, and persistent sleep-wake complaints. Given the link between GMV and sleep spindles in healthy adults and the role of spindles in neural plasticity and protecting sleep against disturbances, we investigated GMV-spindle associations following TBI. In this cross-sectional study, 27 adults with chronic moderate to severe TBI (32.0 ± 12.2 years old) and 32 healthy controls (29.2 ± 11.5 years old) underwent full-night polysomnography and 3-Tesla MRI. Spindle density, amplitude, frequency, duration, and sigma spectral power (11-16 Hz) were computed. We tested GMV-spindle associations in 1) clusters with GMV loss following TBI (right and left frontotemporal and left temporal) and 2) regions previously linked to spindles in healthy adults (hippocampus, insula, cingulate, supplementary motor area, cerebellum, Heschl's gyri, thalamus, medial prefrontal cortex, putamen, and pallidum). Multiple regression analyses were performed with Group as a moderator, controlled for age. Across all participants, higher spindle amplitude and sigma power were associated with larger GMVs in the left frontotemporal, left temporal, thalamic, and medial prefrontal regions. Faster spindle frequency was associated with larger GMV in most regions, though for the left and right frontotemporal regions and hippocampus, these associations were observed only in controls. No Group effects were found for spindle characteristics. The lack of stronger GMV-spindle associations following TBI and the absence of Group effects for spindle characteristics suggest spindles' resilience to post-traumatic GMV loss.

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YNICL Journal 2022 Journal Article

Medial temporal lobe and obstructive sleep apnea: Effect of sex, age, cognitive status and free-water

Marie-Ève Martineau-Dussault
Claire André
Véronique Daneault
Andrée-Ann Baril
Katia Gagnon
Hélène Blais
Dominique Petit
Jacques Y. Montplaisir

Medial temporal structures, namely the hippocampus, the entorhinal cortex and the parahippocampal gyrus, are particularly vulnerable to Alzheimer's disease and hypoxemia. Here, we tested the associations between obstructive sleep apnea (OSA) severity and medial temporal lobe volumes in 114 participants aged 55-86 years (35 % women). We also investigated the impact of sex, age, cognitive status, and free-water fraction correction on these associations. Increased OSA severity was associated with larger hippocampal and entorhinal cortex volumes in women, but not in men. Greater OSA severity also correlated with increased hippocampal volumes in participants with amnestic mild cognitive impairment, but not in cognitively unimpaired participants, regardless of sex. Using free-water corrected volumes eliminated all significant associations with OSA severity. Therefore, the increase in medial temporal subregion volumes may possibly be due to edema. Whether these structural manifestations further progress to neuronal death in non-treated OSA patients should be investigated.

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YNIMG Journal 2018 Journal Article

Transient synchronization of hippocampo-striato-thalamo-cortical networks during sleep spindle oscillations induces motor memory consolidation

Arnaud Boutin
Basile Pinsard
Arnaud Boré
Julie Carrier
Stuart M. Fogel
Julien Doyon

Sleep benefits motor memory consolidation. This mnemonic process is thought to be mediated by thalamo-cortical spindle activity during NREM-stage2 sleep episodes as well as changes in striatal and hippocampal activity. However, direct experimental evidence supporting the contribution of such sleep-dependent physiological mechanisms to motor memory consolidation in humans is lacking. In the present study, we combined EEG and fMRI sleep recordings following practice of a motor sequence learning (MSL) task to determine whether spindle oscillations support sleep-dependent motor memory consolidation by transiently synchronizing and coordinating specialized cortical and subcortical networks. To that end, we conducted EEG source reconstruction on spindle epochs in both cortical and subcortical regions using novel deep-source localization techniques. Coherence-based metrics were adopted to estimate functional connectivity between cortical and subcortical structures over specific frequency bands. Our findings not only confirm the critical and functional role of NREM-stage2 sleep spindles in motor skill consolidation, but provide first-time evidence that spindle oscillations [11–17 Hz] may be involved in sleep-dependent motor memory consolidation by locally reactivating and functionally binding specific task-relevant cortical and subcortical regions within networks including the hippocampus, putamen, thalamus and motor-related cortical regions.

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YNIMG Journal 2015 Journal Article

Maintaining vs. enhancing motor sequence memories: Respective roles of striatal and hippocampal systems

Genevieve Albouy
Stuart Fogel
Bradley R. King
Samuel Laventure
Habib Benali
Avi Karni
Julie Carrier
Edwin M. Robertson

It is now accepted that hippocampal- and striatal-dependent memory systems do not act independently, but rather interact during both memory acquisition and consolidation. However, the respective functional roles of the hippocampus and the striatum in these processes remain unknown. Here, functional magnetic resonance imaging (fMRI) was used in a daytime sleep/wake protocol to investigate this knowledge gap. Using a protocol developed earlier in our lab (Albouy et al. , 2013a), the manipulation of an explicit sequential finger-tapping task, allowed us to isolate allocentric (spatial) and egocentric (motor) representations of the sequence, which were supported by distinct hippocampo- and striato-cortical networks, respectively. Importantly, a sleep-dependent performance enhancement emerged for the hippocampal-dependent memory trace, whereas performance was maintained for the striatal-dependent memory trace, irrespective of the sleep condition. Regression analyses indicated that the interaction between these two systems influenced subsequent performance improvements. While striatal activity was negatively correlated with performance enhancement after both sleep and wakefulness in the allocentric representation, hippocampal activity was positively related to performance improvement for the egocentric representation, but only if sleep was allowed after training. Our results provide the first direct evidence of a functional dissociation in consolidation processes whereby memory stabilization seems supported by the striatum in a time-dependent manner whereas memory enhancement seems linked to hippocampal activity and sleep-dependent processes.

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YNIMG Journal 2014 Journal Article

Off-line consolidation of motor sequence learning results in greater integration within a cortico-striatal functional network

Karen Debas
Julie Carrier
Marc Barakat
Guillaume Marrelec
Pierre Bellec
Abdallah Hadj Tahar
Avi Karni
Leslie G. Ungerleider

The consolidation of motor sequence learning is known to depend on sleep. Work in our laboratory and others have shown that the striatum is associated with this off-line consolidation process. In this study, we aimed to quantify the sleep-dependent dynamic changes occurring at the network level using a measure of functional integration. We directly compared changes in connectivity before and after sleep or the simple passage of daytime. As predicted, the results revealed greater integration within the cortico-striatal network after sleep, but not an equivalent daytime period. Importantly, a similar pattern of results was also observed using a data-driven approach; the increase in integration being specific to a cortico-striatal network, but not to other known functional networks. These findings reveal, for the first time, a new signature of motor sequence consolidation: a greater between-regions interaction within the cortico-striatal system.

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YNIMG Journal 2012 Journal Article

The impact of aging on gray matter structural covariance networks

Maxime Montembeault
Sven Joubert
Julien Doyon
Julie Carrier
Jean-François Gagnon
Oury Monchi
Ovidiu Lungu
Sylvie Belleville

Previous anatomical volumetric studies have shown that healthy aging is associated with gray matter tissue loss in specific cerebral regions. However, these studies may have potentially missed critical elements of age-related brain changes, which largely exist within interrelationships among brain regions. This magnetic resonance imaging research aims to assess the effects of aging on the organization of gray matter structural covariance networks. Here, we used voxel-based morphometry on high-definition brain scans to compare the patterns of gray matter structural covariance networks that sustain different sensorimotor and high-order cognitive functions among young (n =88, mean age=23. 5±3. 1years, female/male=55/33) and older (n =88, mean age=67. 3±5. 9years, female/male=55/33) participants. This approach relies on the assumption that functionally correlated brain regions show correlations in gray matter volume as a result of mutually trophic influences or common experience-related plasticity. We found reduced structural association in older adults compared with younger adults, specifically in high-order cognitive networks. Major differences were observed in the structural covariance networks that subserve the following: a) the language-related semantic network, b) the executive control network, and c) the default-mode network. Moreover, these cognitive functions are typically altered in the older population. Our results indicate that healthy aging alters the structural organization of cognitive networks, shifting from a more distributed (in young adulthood) to a more localized topological organization in older individuals.

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