Publications by authors named "Nicolas Delcroix"

Background: Many patients treated for breast cancer (BC) complain about cognitive difficulties affecting their daily lives. Recently, sleep disturbances and circadian rhythm disruptions have been brought to the fore as potential contributors to cognitive difficulties in patients with BC. Yet, studies on these factors as well as their neural correlates are scarce.

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  • Thoracic radiation therapy can lead to accelerated atherosclerosis and aortic valve stenosis (AS), prompting this study to investigate targeted aortic valve irradiation effects in mice.
  • The study used echocardiography and MRI to assess AS and aortic inflammation, finding a significant increase in peak aortic jet velocity and remodeling in ApoE mice after irradiation.
  • The results indicate that targeted radiation can model aortic valve remodeling similar to human conditions, particularly in ApoE mice, suggesting the potential for future therapeutic interventions.
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There is increasing evidence of different subtypes of individuals with mild cognitive impairment (MCI). An important line of research is whether neuropsychologically-defined subtypes have distinct patterns of neurodegeneration and cerebrospinal fluid (CSF) biomarker composition. In our study, we demonstrated that MCI participants of the ADNI database (N = 640) can be discriminated into 3 coherent neuropsychological subgroups.

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Medial temporal lobe (MTL) subregions are differentially affected in Alzheimer's disease (AD), with a specific involvement of the entorhinal cortex (ERC), perirhinal cortex and hippocampal cornu ammonis (CA)1. While amyloid (Aβ) and APOEε4 are respectively the first molecular change and the main genetic risk factor in AD, their links with MTL atrophy remain relatively unclear. Our aim was to uncover these effects using baseline data from 130 participants included in the Age-Well study, for whom ultra-high-resolution structural MRI, amyloid-PET and APOEε4 genotype were available.

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Insomnia disorder has been associated with poor executive functioning. Functional imaging studies of executive functioning in insomnia are scarce and inconclusive. Because the Attentional Network Test relies on well-defined cortical networks and sensitively distinguishes different aspects of executive function, it might reveal brain functional alterations in relatively small samples of patients.

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Empirically based literature suggests that avoidance/approach motivation arising from color-meaning associations assume a key mediational role in the color effect during psychological functioning. Even if several studies investigated color-meaning associations through different methodological approaches, no study investigated specific color-meaning associations (1) through continuous measures (2) for both positive and negative meanings. In addition, color effects are not unequivocal, and interindividual variability issues are still underexplored.

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Objective: The hippocampus is connected to 2 distinct cortical brain networks, the posterior-medial and the anterior-temporal networks, involving different medial temporal lobe (MTL) subregions. The aim of this study was to assess the functional alterations of these 2 networks, their changes over time, and links to cognition in Alzheimer's disease.

Methods: We assessed MTL connectivity in 53 amyloid-β-positive patients with mild cognitive impairment and AD dementia and 68 healthy elderly controls, using resting-state functional magnetic resonance imaging, cross-sectionally and longitudinally.

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Whether the etiology of schizophrenia remains unknown, its multifactorial aspect is conversely now well admitted. However, most preclinical models of the disease still rely on a mono-factorial construction and do not allow discover unequivocal treatments, particularly for negative and cognitive symptoms. The main interaction factors that have been implicated in schizophrenia are a genetic predisposition and unfavorable environmental factors.

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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 who are cognitively unimpaired, including changes in amyloid deposition, gray matter volume, perfusion, and glucose metabolism.

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Purpose: Preclinical imaging of endothelial activation and mineralization using both positron emission tomography (PET) and magnetic resonance (MR) remains scarce.

Procedures: A group of uremic ApoE (Ur), non-uremic ApoE (NUr), and control C57Bl/6 J mice (Ctl) were investigated. Mineralization process was assessed using sodium fluoride ([18F]NaF) PET, and MR imaging combined with intravenous injection of MPIO-αVCAM-1 was used to evaluate endothelial activation.

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Corpus callosum (CC) volume and surface (macrostructural) studies remain controversial and have not considered the illness duration (ID) systematically. Regardless of ID, some CC macrostructural studies have shown no difference between SZ patients and healthy controls (HC), whereas others have reported macrostructural abnormalities in SZ. Conversely, CC microstructural studies are more in agreement with alterations in CC integrity regardless of the patients' ID, but the direction and degree of these abnormalities over time remain unknown.

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Purpose: The purpose of this study was to assess the impact of positron emission tomography/X-ray computed tomography (PET/CT) acquisition and reconstruction parameters on the assessment of mineralization process in a mouse model of atherosclerosis.

Procedures: All experiments were performed on a dedicated preclinical PET/CT system. CT was evaluated using five acquisition configurations using both a tungsten wire phantom for in-plane resolution assessment and a bar pattern phantom for cross-plane resolution.

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It was previously reported that normobaric oxygen therapy (NBO) significantly affected T2-weighted imaging in a mouse model of intracerebral hemorrhage (ICH). However, it is unclear whether a similar phenomenon exists in large volume ICH as seen in human pathology. We investigated the effects of NBO on T2-weighted images in a pig model of ICH.

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Quantitative imaging modalities for the analysis of hypoxia in brain tumors are lacking. The objective of this study was to generate absolute maps of tissue pO from [F]-FMISO images in glioblastoma and less aggressive glioma patients in order to quantitatively assess tumor hypoxia. An ancillary objective was to compare estimated pO values to other biomarkers: perfusion weighted imaging (PWI) and tumor metabolism obtained from H-MR mono-voxel spectroscopy (MRS).

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Objectives: The question of whether there is a continuum or a dichotomy among patients with schizophrenia (SZ) and bipolar disorders (BD) has not been clearly resolved and remains a challenge. Thus, the identification of specific biomarkers of these disorders might be helpful. The present study investigated the volume of the corpus callosum (CC) and functional lateralization for language as potential biomarkers and their relationships in SZ and BD.

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Objectives: Impairments in language production are common of schizophrenia (SZ) and bipolar disorder (BD). Identifying distinct functional connectivity (FC) patterns in SZ and BD may provide biomarkers for their diagnoses.

Methods: Forty-nine participants (15 SZ, 14 BD and 20 healthy controls (HC)) underwent a verbal fluency task consisting of mentally generating verbs in French, alternated with periods of silence.

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The dysconnectivity theory of schizophrenia proposes that schizophrenia symptoms arise from abnormalities in neuronal synchrony. Resting-state Functional Connectivity (FC) techniques allow us to highlight synchronization of large-scale networks, the Resting-state Networks (RNs). A large body of work suggests that disruption of RN synchronization could give rise to specific schizophrenia symptoms.

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  • The study examines white matter abnormalities related to auditory verbal hallucinations (AVHs) in schizophrenia patients by comparing those with AVHs (SZ+) and those without (SZ-) to healthy controls (HCs) using advanced imaging techniques.
  • It involved 27 SZ+, 12 SZ-, and 34 HCs, measuring factors of white matter integrity, specifically in pathways associated with speech and auditory processing.
  • Results showed increased diffusivities and decreased fractional anisotropy in the fasciculi for both SZ groups, with significant IAP changes only in SZ+, indicating the IAP's potential link to AVH susceptibility.
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The alleviation of hypoxia in glioblastoma with carbogen to improve treatment has met with limited success. Our hypothesis is that the eventual benefits of carbogen depend on the capacity for vasodilation. We examined, with MRI, changes in fractional cerebral blood volume, blood oxygen saturation, and blood oxygenation level dependent signals in response to carbogen.

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Background: Atlases of brain anatomical ROIs are widely used for functional MRI data analysis. Recently, it was proposed that an atlas of ROIs derived from a functional brain parcellation could be advantageous, in particular for understanding how different regions share information. However, functional atlases so far proposed do not account for a crucial aspect of cerebral organization, namely homotopy, i.

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  • The study investigates the relationship between structural connectivity in the corpus callosum (CC) and leftward functional lateralization for language in schizophrenia, compared to healthy participants using fMRI and DTI.
  • Results indicate that schizophrenia patients showed higher mean and radial diffusivity values linked to decreased leftward lateralization, while healthy controls exhibited the opposite trend.
  • Although a connection between CC integrity and hemispheric specialization for language was found, the study did not determine the exact nature of this relationship in schizophrenia patients.
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Reasoners make systematic logical errors by giving heuristic responses that reflect deviations from the logical norm. Influential studies have suggested first that our reasoning is often biased because we minimize cognitive effort to surpass a cognitive conflict between heuristic response from system 1 and analytic response from system 2 thinking. Additionally, cognitive control processes might be necessary to inhibit system 1 responses to activate a system 2 response.

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Objectives: This study aimed to compare the functional and gray matter asymmetries in patients with schizophrenia (SZ), patients with bipolar disorders (BD), and healthy controls (HCs) to test whether decreased leftward functional hemispheric lateralization and gray matter volume asymmetry could mark the boundary between schizophrenia and bipolar disorder.

Methods: A total of 31 right-handed SZ and 20 right-handed BD underwent a session of functional MRI with a speech listening paradigm. Participants were matched with HCs for gender, age, and education.

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Schizophrenia is a mental disorder characterized by language disorders. Studies reveal that both a functional dysconnectivity and a disturbance in the integrity of white matter fibers are implicated in the language process in patients with schizophrenia. Here, we investigate the relationship between functional connectivity within a language-comprehension network and anatomical connectivity using fiber tracking in schizophrenia.

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Background: Schizophrenia is a mental disorder characterized by functional abnormalities in the language network. Anatomical white matter (WM) abnormalities (volume and integrity) have also been reported for this pathology. Nevertheless, few studies have investigated anatomo-functional relationships in schizophrenia, and none has focused on the language comprehension network in relation to various diffusion parameters.

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