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1.
Brain Struct Funct ; 229(4): 1001-1010, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38502330

RESUMO

The probabilistic topography and inter-individual variability of the pituitary gland (PG) remain undetermined. The absence of a standardized reference atlas hinders research on PG volumetrics. In this study, we aimed at creating maximum probability maps for the anterior and posterior PG in young female adults. We manually delineated the anterior and posterior parts of the pituitary glands in 26 healthy subjects using high-resolution MRI T1 images. A three-step procedure and a cost function-masking approach were employed to optimize spatial normalization for the PG. We generated probabilistic atlases and maximum probability maps, which were subsequently coregistered back to the subjects' space and compared to manual delineations. Manual measurements led to a total pituitary volume of 705 ± 88 mm³, with the anterior and posterior volumes measuring 614 ± 82 mm³ and 91 ± 20 mm³, respectively. The mean relative volume difference between manual and atlas-based estimations was 1.3%. The global pituitary atlas exhibited an 80% (± 9%) overlap for the DICE index and 67% (± 11%) for the Jaccard index. Similarly, these values were 77% (± 13%) and 64% (± 14%) for the anterior pituitary atlas and 62% (± 21%) and 47% (± 17%) for the posterior PG atlas, respectively. We observed a substantial concordance and a significant correlation between the volume estimations of the manual and atlas-based methods for the global pituitary and anterior volumes. The maximum probability maps of the anterior and posterior PG lay the groundwork for automatic atlas-based segmentation methods and the standardized analysis of large PG datasets.


Assuntos
Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Adulto , Humanos , Feminino , Processamento de Imagem Assistida por Computador/métodos , Imageamento por Ressonância Magnética/métodos , Algoritmos , Hipófise/diagnóstico por imagem
2.
Biomed Opt Express ; 15(1): 387-412, 2024 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-38223192

RESUMO

Spectral unmixing designates techniques that allow to decompose measured spectra into linear or non-linear combination of spectra of all targets (endmembers). This technique was initially developed for satellite applications, but it is now also widely used in biomedical applications. However, several drawbacks limit the use of these techniques with standard optical devices like RGB cameras. The devices need to be calibrated and a a priori on the observed scene is often necessary. We propose a new method for estimating endmembers and their proportion automatically and without calibration of the acquisition device based on near separable non-negative matrix factorization. This method estimates the endmembers on spectra of absorbance changes presenting periodic events. This is very common in in vivo biomedical and medical optical imaging where hemodynamics dominate the absorbance fluctuations. We applied the method for identifying functional brain areas during neurosurgery using four different RGB cameras (an industrial camera, a smartphone and two surgical microscopes). Results obtained with the auto-calibration method were consistent with the intraoperative gold standards. Endmembers estimated with the auto-calibration method were similar to the calibrated endmembers used in the modified Beer-Lambert law. The similarity was particularly strong when both cardiac and respiratory periodic events were considered. This work can allow a widespread use of spectral imaging in the industrial or medical field.

3.
Brain Struct Funct ; 229(1): 195-205, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38062204

RESUMO

Patients with Anorexia Nervosa (AN) and athletes share intense physical activity and pituitary hormonal disturbances related to absolute (AN) or relative (athletes) undernutrition. Pituitary gland (PG) structure evaluations in those conditions are scarce, and did not differentiate anterior from posterior lobe. We evaluated the structure-function relationship of anterior and posterior PG in AN and athletes, and potential reversibility of this alteration in a group of weight-recovered patients (AN_Rec). Manual delineation of anterior (AP) and posterior (PP) PG was performed on T1-weighted MR images in 17 women with AN, 15 women with AN_Rec, 18 athletes women and 25 female controls. Anthropometric, hormonal, and psychometric parameters were explored and correlated with PG volumes. AP volume (APV) was lower in AN (448 ± 82 mm3), AN_Rec (505 ± 59 mm3), and athletes (540 ± 101 mm3) vs. Controls (615 ± 61 mm3, p < 0.00001, p < 0.00001 and p = 0.02, respectively); and smaller in AN vs. AN_Rec (p = 0.007). PP volume did not show any differences between the groups. APV was positively correlated with weight (R = 0.36, p = 0.011) in AN, and luteinizing hormone (R = 0.35, p = 0.014) in total group. In AN, mean growth hormone (GH) was negatively correlated with global pituitary volume (R = 0.31, p = 0.031) and APV (R = 0.29, p = 0.037). Absolute and relative undernutrition led to a decreased anterior pituitary gland volume, which was reversible with weight gain, correlated with low bodyweight, and blockade of gonadal hypothalamic-pituitary axis. Intriguing inverse correlation between anterior pituitary gland volume and GH plasma level could suggests a low storage capacity of anterior pituitary gland and increased reactivity to low insulin-like growth factor type 1.


Assuntos
Anorexia Nervosa , Desnutrição , Adeno-Hipófise , Feminino , Humanos , Anorexia Nervosa/metabolismo , Hipófise/metabolismo , Adeno-Hipófise/metabolismo , Relação Estrutura-Atividade , Fator de Crescimento Insulin-Like I/metabolismo
4.
Cogn Neuropsychol ; 40(2): 95-118, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-37632139

RESUMO

It is increasingly being recognized that new declarative, consciously accessible information can be learned in anterograde amnesia, but it is not clear whether this learning is supported by episodic or semantic memory. We report a case of a 55-year-old man who experienced severe amnesia after limited damage to the medial temporal lobe following neurosurgical complications. His general cognitive performance and knowledge of new French words and public events that occurred before and after the onset of amnesia were assessed. Performance remained satisfactory on post-morbid vocabulary and public events, with a drop in performance observed for very recent public events only, while knowledge of very recent vocabulary was comparable to that of the control subjects. The implications of these findings for our understanding of the underlying learning mechanisms are discussed. This is the first report of acquisition of consciously accessible postmorbid knowledge of public events in a patient with severe amnesia.


Assuntos
Amnésia Anterógrada , Memória Episódica , Masculino , Humanos , Pessoa de Meia-Idade , Semântica , Amnésia Anterógrada/complicações , Amnésia/complicações , Amnésia/psicologia , Aprendizagem , Testes Neuropsicológicos
5.
Neuroimage ; 278: 120286, 2023 09.
Artigo em Inglês | MEDLINE | ID: mdl-37487945

RESUMO

Complementary technique to preoperative fMRI and electrical brain stimulation (EBS) for glioma resection could improve dramatically the surgical procedure and patient care. Intraoperative RGB optical imaging is a technique for localizing functional areas of the human cerebral cortex that can be used during neurosurgical procedures. However, it still lacks robustness to be used with neurosurgical microscopes as a clinical standard. In particular, a robust quantification of biomarkers of brain functionality is needed to assist neurosurgeons. We propose a methodology to evaluate and optimize intraoperative identification of brain functional areas by RGB imaging. This consist in a numerical 3D brain model based on Monte Carlo simulations to evaluate intraoperative optical setups for identifying functional brain areas. We also adapted fMRI Statistical Parametric Mapping technique to identify functional brain areas in RGB videos acquired for 12 patients. Simulation and experimental results were consistent and showed that the intraoperative identification of functional brain areas is possible with RGB imaging using deoxygenated hemoglobin contrast. Optical functional identifications were consistent with those provided by EBS and preoperative fMRI. We also demonstrated that a halogen lighting may be particularity adapted for functional optical imaging. We showed that an RGB camera combined with a quantitative modeling of brain hemodynamics biomarkers can evaluate in a robust way the functional areas during neurosurgery and serve as a tool of choice to complement EBS and fMRI.


Assuntos
Neoplasias Encefálicas , Glioma , Humanos , Neoplasias Encefálicas/diagnóstico por imagem , Neoplasias Encefálicas/cirurgia , Mapeamento Encefálico/métodos , Encéfalo/diagnóstico por imagem , Encéfalo/cirurgia , Imageamento por Ressonância Magnética/métodos , Glioma/diagnóstico por imagem , Glioma/cirurgia , Procedimentos Neurocirúrgicos/métodos
6.
Trials ; 24(1): 141, 2023 Feb 24.
Artigo em Inglês | MEDLINE | ID: mdl-36829240

RESUMO

BACKGROUND: In parallel to the traditional symptomatology, deficits in cognition (memory, attention, reasoning, social functioning) contribute significantly to disability and suffering in individuals with schizophrenia. Cognitive deficits have been closely linked to alterations in early auditory processes (EAP) that occur in auditory cortical areas. Preliminary evidence indicates that cognitive deficits in schizophrenia can be improved with a reliable and safe non-invasive brain stimulation technique called tDCS (transcranial direct current stimulation). However, a significant proportion of patients derive no cognitive benefits after tDCS treatment. Furthermore, the neurobiological mechanisms of cognitive changes after tDCS have been poorly explored in trials and are thus still unclear. METHOD: The study is designed as a randomized, double-blind, 2-arm parallel-group, sham-controlled, multicenter trial. Sixty participants with recent-onset schizophrenia and cognitive impairment will be randomly allocated to receive either active (n=30) or sham (n=30) tDCS (20-min, 2-mA, 10 sessions during 5 consecutive weekdays). The anode will be placed over the left dorsolateral prefrontal cortex and the cathode over the left auditory cortex. Cognition, tolerance, symptoms, general outcome and EAP (measured with EEG and multimodal MRI) will be assessed prior to tDCS (baseline), after the 10 sessions, and at 1- and 3-month follow-up. The primary outcome will be the number of responders, defined as participants demonstrating a cognitive improvement ≥Z=0.5 from baseline on the MATRICS Consensus Cognitive Battery total score at 1-month follow-up. Additionally, we will measure how differences in EAP modulate individual cognitive benefits from active tDCS and whether there are changes in EAP measures in responders after active tDCS. DISCUSSION: Besides proposing a new fronto-temporal tDCS protocol by targeting the auditory cortical areas, we aim to conduct a randomized controlled trial (RCT) with follow-up assessments up to 3 months. In addition, this study will allow identifying and assessing the value of a wide range of neurobiological EAP measures for predicting and explaining cognitive deficit improvement after tDCS. The results of this trial will constitute a step toward the use of tDCS as a therapeutic tool for the treatment of cognitive impairment in recent-onset schizophrenia. TRIAL REGISTRATION: ClinicalTrials.gov NCT05440955. Prospectively registered on July 1st, 2022.


Assuntos
Disfunção Cognitiva , Esquizofrenia , Estimulação Transcraniana por Corrente Contínua , Humanos , Estimulação Transcraniana por Corrente Contínua/métodos , Resultado do Tratamento , Esquizofrenia/terapia , Método Duplo-Cego , Córtex Pré-Frontal , Biomarcadores , Ensaios Clínicos Controlados Aleatórios como Assunto , Estudos Multicêntricos como Assunto
7.
Diagnostics (Basel) ; 11(11)2021 Nov 09.
Artigo em Inglês | MEDLINE | ID: mdl-34829414

RESUMO

RGB optical imaging is a marker-free, contactless, and non-invasive technique that is able to monitor hemodynamic brain response following neuronal activation using task-based and resting-state procedures. Magnetic resonance imaging (fMRI) and functional near infra-red spectroscopy (fNIRS) resting-state procedures cannot be used intraoperatively but RGB imaging provides an ideal solution to identify resting-state networks during a neurosurgical operation. We applied resting-state methodologies to intraoperative RGB imaging and evaluated their ability to identify resting-state networks. We adapted two resting-state methodologies from fMRI for the identification of resting-state networks using intraoperative RGB imaging. Measurements were performed in 3 patients who underwent resection of lesions adjacent to motor sites. The resting-state networks were compared to the identifications provided by RGB task-based imaging and electrical brain stimulation. Intraoperative RGB resting-state networks corresponded to RGB task-based imaging (DICE:0.55±0.29). Resting state procedures showed a strong correspondence between them (DICE:0.66±0.11) and with electrical brain stimulation. RGB imaging is a relevant technique for intraoperative resting-state networks identification. Intraoperative resting-state imaging has several advantages compared to functional task-based analyses: data acquisition is shorter, less complex, and less demanding for the patients, especially for those unable to perform the tasks.

8.
Front Hum Neurosci ; 15: 638887, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33633557

RESUMO

The loss or absence of vision is probably one of the most incapacitating events that can befall a human being. The importance of vision for humans is also reflected in brain anatomy as approximately one third of the human brain is devoted to vision. It is therefore unsurprising that throughout history many attempts have been undertaken to develop devices aiming at substituting for a missing visual capacity. In this review, we present two concepts that have been prevalent over the last two decades. The first concept is sensory substitution, which refers to the use of another sensory modality to perform a task that is normally primarily sub-served by the lost sense. The second concept is cross-modal plasticity, which occurs when loss of input in one sensory modality leads to reorganization in brain representation of other sensory modalities. Both phenomena are training-dependent. We also briefly describe the history of blindness from ancient times to modernity, and then proceed to address the means that have been used to help blind individuals, with an emphasis on modern technologies, invasive (various type of surgical implants) and non-invasive devices. With the advent of brain imaging, it has become possible to peer into the neural substrates of sensory substitution and highlight the magnitude of the plastic processes that lead to a rewired brain. Finally, we will address the important question of the value and practicality of the available technologies and future directions.

9.
MAGMA ; 34(3): 437-450, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33048262

RESUMO

OBJECTIVE: In this perfusion magnetic resonance imaging study, the performances of different pseudo-continuous arterial spin labeling (PCASL) sequences were compared: two-dimensional (2D) single-shot readout with simultaneous multislice (SMS), 2D single-shot echo-planar imaging (EPI) and multishot three-dimensional (3D) gradient and spin echo (GRASE) sequences combined with a background-suppression (BS) module. MATERIALS AND METHODS: Whole-brain PCASL images were acquired from seven healthy volunteers. The performance of each protocol was evaluated by extracting regional cerebral blood flow (rCBF) measures using an inline morphometric segmentation prototype. Image data postprocessing and subsequent statistical analyses enabled comparisons at the regional and sub-regional levels. RESULTS: The main findings were as follows: (i) Mean global CBF obtained across methods was were highly correlated, and these correlations were significantly higher among the same readout sequences. (ii) Temporal signal-to-noise ratio and gray-matter-to-white-matter CBF ratio were found to be equivalent for all 2D variants but lower than those of 3D-GRASE. DISCUSSION: Our study demonstrates that the accelerated SMS readout can provide increased acquisition efficiency and/or a higher temporal resolution than conventional 2D and 3D readout sequences. Among all of the methods, 3D-GRASE showed the lowest variability in CBF measurements and thus highest robustness against noise.


Assuntos
Imageamento Tridimensional , Encéfalo , Circulação Cerebrovascular , Imagem Ecoplanar , Humanos , Angiografia por Ressonância Magnética , Marcadores de Spin
10.
Front Neurosci ; 14: 815, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32848575

RESUMO

In congenital blindness (CB), tactile, and auditory information can be reinterpreted by the brain to compensate for visual information through mechanisms of brain plasticity triggered by training. Visual deprivation does not cause a cognitive spatial deficit since blind people are able to acquire spatial knowledge about the environment. However, this spatial competence takes longer to achieve but is eventually reached through training-induced plasticity. Congenitally blind individuals can further improve their spatial skills with the extensive use of sensory substitution devices (SSDs), either visual-to-tactile or visual-to-auditory. Using a combination of functional and anatomical neuroimaging techniques, our recent work has demonstrated the impact of spatial training with both visual to tactile and visual to auditory SSDs on brain plasticity, cortical processing, and the achievement of certain forms of spatial competence. The comparison of performances between CB and sighted people using several different sensory substitution devices in perceptual and sensory-motor tasks uncovered the striking ability of the brain to rewire itself during perceptual learning and to interpret novel sensory information even during adulthood. We discuss here the implications of these findings for helping blind people in navigation tasks and to increase their accessibility to both real and virtual environments.

11.
Sci Rep ; 10(1): 1662, 2020 02 03.
Artigo em Inglês | MEDLINE | ID: mdl-32015357

RESUMO

Distinction between deep and superficial middle cerebral artery (MCA) territories and their junctional vascular area (the internal borderzone or IBZ) constitutes a predictor of stroke patient outcome. However, the IBZ boundaries are not well-defined because of substantial anatomical variance. Here, we built a statistical estimate of the IBZ and tested its vulnerability to ischemia using an independent sample. First, we used delineated lesions of 122 patients suffering of chronic ischemic stroke grouped in deep, superficial and territorial topographies and statistical comparisons to generate a probabilistic estimate of the IBZ. The IBZ extended from the insular cortex to the internal capsule and the anterior part of the caudate nucleus head. The IBZ showed the highest lesion frequencies (~30% on average across IBZ voxels) in our chronic stroke patients but also in an independent sample of 87 acute patients. Additionally, the most important apparent diffusion coefficient reductions (-6%), which reflect stroke severity, were situated within our IBZ estimate. The IBZ was most severely injured in case of a territorial infarction. Then, our results are in favour of an increased IBZ vulnerability to ischemia. Moreover, our probabilistic estimates of deep, superficial and IBZ regions can help the everyday spatial classification of lesions.


Assuntos
Isquemia Encefálica/diagnóstico por imagem , Acidente Vascular Cerebral/diagnóstico por imagem , Doença Aguda , Idoso , Idoso de 80 Anos ou mais , Doença Crônica , Imagem de Difusão por Ressonância Magnética/métodos , Imagem de Difusão por Ressonância Magnética/estatística & dados numéricos , Feminino , Humanos , Infarto da Artéria Cerebral Média/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Artéria Cerebral Média/diagnóstico por imagem , Modelos Estatísticos , Estudos Retrospectivos
12.
Sci Rep ; 10(1): 495, 2020 01 16.
Artigo em Inglês | MEDLINE | ID: mdl-31949207

RESUMO

Despite the fact that complete visual deprivation leads to volumetric reductions in brain structures associated with spatial learning, blind individuals are still able to navigate. The neural structures involved in this function are not fully understood. Our study aims to correlate the performance of congenitally blind individuals (CB) and blindfolded sighted controls (SC) in a life-size obstacle-course using a visual-to-tactile sensory substitution device, with the size of brain structures (voxel based morphometry-VBM-) measured through structural magnetic resonance Imaging (MRI). VBM was used to extract grey matter volumes within several a-priori defined brain regions in all participants. Principal component analysis was utilized to group brain regions in factors and orthogonalize brain volumes. Regression analyses were then performed to link learning abilities to these factors. We found that (1) both CB and SC were able to learn to detect and avoid obstacles; (2) their learning rates for obstacle detection and avoidance correlated significantly with the volume of brain structures known to be involved in spatial skills. There is a similar relation between regions of the dorsal stream network and avoidance for both SC and CB whereas for detection, SC rely more on medial temporal lobe structures and CB on sensorimotor areas.


Assuntos
Cegueira/congênito , Cegueira/psicologia , Substância Cinzenta/diagnóstico por imagem , Aprendizagem Espacial/fisiologia , Adulto , Idoso , Cegueira/diagnóstico por imagem , Mapeamento Encefálico , Estudos de Casos e Controles , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Análise de Componente Principal , Análise de Regressão , Percepção Espacial/fisiologia , Adulto Jovem
13.
J Neuroradiol ; 46(3): 207-213, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30731145

RESUMO

INTRODUCTION: Medulloblastoma is the most common malignant cerebral tumor during childhood, arising in the posterior fossa. Children treated for medulloblastoma often experience working memory (WM) deficits, affecting their quality of life and school performance. The aim of the present study undertaken to describe the cerebellar involvement in WM deficits observed in these children. MATERIAL AND METHODS: 23 healthy children and 11 children treated for medulloblastoma were included into study. All subjects performed a detailed neuropsychological examination, an anatomical and functional MRI. Stimuli were presented to the participants with alternating sensory modality and nature of communication in a block design during functional magnetic resonance imaging acquisitions. Non-parametric tests were used for analyzing neuropsychological and behavioral data. SPM8 and SUIT (Spatially Unbiased Atlas Template) were used for anatomical and functional MRI data analyses. RESULTS: Patients had cerebellar resections mainly located in the left posterior lobe. Patients had significantly reduced intelligence quotient, central executive and visuospatial WM. In healthy children group, fMRI showed activations for non-verbal and visuospatial WM in the left posterior cerebellar lobe. CONCLUSION: This study provides further evidence that left posterior cerebellar lobe plays a critical role in WM. Indeed, lesions of left posterior cerebellar lobe were associated with WM impairment in children treated for cerebellar medulloblastoma. Additionally, fMRI using WM tasks showed activation in the left posterior cerebellar lobe in healthy children. Taken together, these findings may help for improving treatment and rehabilitation of children referred for cerebellar tumor.


Assuntos
Neoplasias Encefálicas/diagnóstico por imagem , Neoplasias Encefálicas/psicologia , Doenças Cerebelares/diagnóstico por imagem , Doenças Cerebelares/psicologia , Imageamento por Ressonância Magnética/métodos , Meduloblastoma/diagnóstico por imagem , Meduloblastoma/psicologia , Memória de Curto Prazo , Adolescente , Mapeamento Encefálico , Neoplasias Encefálicas/cirurgia , Criança , Feminino , França , Humanos , Deficiência Intelectual/etiologia , Masculino , Meduloblastoma/cirurgia , Testes Neuropsicológicos , Procedimentos Neurocirúrgicos , Qualidade de Vida , Fatores de Risco
14.
Confl Health ; 12: 40, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30214472

RESUMO

BACKGROUND: Patients with diabetes require knowledge and skills to self-manage their disease, a challenging aspect of treatment that is difficult to address in humanitarian settings. Due to the lack of literature and experience regarding diabetes self-management, education and support (DSMES) in refugee populations, Medecins Sans Frontieres (MSF) undertook a DSMES survey in a cohort of diabetes patients seen in their primary health care program in Lebanon. METHODS: Structured interviews were conducted with diabetes patients in three primary care clinics between January and February 2015. Scores (0-10) were calculated to measure diabetes core knowledge in each patient (the DSMES score). Awareness of long-term complications and educational preferences were also assessed. Analyses were conducted using Stata software, version 14.1 (StataCorp). Simple and multiple linear regression models were used to determine associations between various patient factors and the DSMES Score. RESULTS: A total of 292 patients were surveyed. Of these, 92% had type 2 diabetes and most (70%) had been diagnosed prior to the Syrian conflict. The mean DSMES score was 6/10. Having secondary education, previous diabetes education, a 'diabetes confidant', and insulin use were each associated with a higher DSMES Score. Lower scores were significantly more likely to be seen in participants with increasing age and in patients who were diagnosed during the Syrian conflict. Long-term complications of diabetes most commonly known by patients were vision related complications (68% of patients), foot ulcers (39%), and kidney failure (38%). When asked about the previous Ramadan, 56% of patients stated that they undertook a full fast, including patients with type 1 diabetes. Individual and group lessons were preferred by more patients than written, SMS, telephone or internet-based educational delivery models. CONCLUSIONS: DSMES should be patient and context appropriate. The variety and complexities of humanitarian settings provide particular challenges to its appropriate provision. Understanding patient baseline DSMES levels and needs provides a useful basis for humanitarian organizations seeking to provide diabetes care.

15.
Soc Cogn Affect Neurosci ; 13(4): 381-390, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29069508

RESUMO

Functional dysconnection is increasingly recognized as a core pathological feature in schizophrenia. Aberrant interactions between regions of the cortico-limbic circuit may underpin the abnormal emotional processing associated with this illness. We used a functional magnetic resonance imaging (fMRI) paradigm designed to dissociate the various components of the cortico-limbic circuit (i.e. a ventral automatic circuit that is intertwined with a dorsal cognitive circuit), in order to explore bottom-up appraisal as well as top-down control during emotion processing. In schizophrenia patients compared to healthy controls, bottom-up processes were associated with reduced interaction between the amygdala and both the anterior cingulate cortex (ACC) and the dorsolateral prefrontal cortex (DLPFC). Contrariwise, top-down control processes led to stronger connectivity between the ventral affective and the dorsal cognitive circuits, i.e. heightened interactions between the ventral ACC and the DLPFC as well as between dorsal and ventral ACC. These findings offer a comprehensive view of the cortico-limbic dysfunction in schizophrenia. They confirm previous results of impaired propagation of information between the amygdala and the prefrontal cortex and suggest a defective functional segregation in the dorsal cognitive part of the cortico-limbic circuit.

16.
Schizophr Res ; 184: 69-72, 2017 06.
Artigo em Inglês | MEDLINE | ID: mdl-27979699

RESUMO

Childhood trauma strongly impacts emotional responses in schizophrenia. We have explored an association between early trauma and the amygdala functional connectivity using generalized psychophysiological interaction during an emotional task. Twenty-one schizophrenia patients and twenty-five controls were included. In schizophrenia patients, higher levels of sexual abuse and physical neglect during childhood were associated with decreased connectivity between the amygdala and the posterior cingulate/precuneus region. Additionally, patients showed decreased coupling between the amygdala and the posterior cingulate/precuneus region compared to controls. These findings suggest that early trauma could impact later connectivity in specific stress-related circuits affecting self-consciousness and social cognition in schizophrenia.


Assuntos
Adultos Sobreviventes de Eventos Adversos na Infância , Tonsila do Cerebelo/fisiopatologia , Córtex Cerebral/fisiopatologia , Conectoma/métodos , Emoções/fisiologia , Esquizofrenia/fisiopatologia , Adulto , Sobreviventes Adultos de Maus-Tratos Infantis/psicologia , Adultos Sobreviventes de Eventos Adversos na Infância/psicologia , Tonsila do Cerebelo/diagnóstico por imagem , Córtex Cerebral/diagnóstico por imagem , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Reconhecimento Visual de Modelos/fisiologia , Adulto Jovem
17.
Brain Imaging Behav ; 11(1): 293-299, 2017 02.
Artigo em Inglês | MEDLINE | ID: mdl-26843003

RESUMO

To prospectively evaluate the prevalence of incidental findings on standardized brain MRI scans in a cohort of elderly subjects. All participants provided written informed consent to participate in this prospective study, which was approved by the institutional review board and was HIPAA compliant. There were 503 subjects (75.3 ± 0.9 years of age, 58 % women) who received brain MRIs on a 1.5-T scanner using a standard acquisition protocol. All scans were reviewed by an experienced neuroradiologist. Incidental findings were stratified as follows: 1, no incidental findings; 2, incidental findings without clinical significance; 3, incidental findings with clinical significance or requiring clinical follow-up. Incidental findings were identified in 77.9 % of subjects. Among 392 scans that exhibited incidental findings, 494 abnormalities were identified. The most common findings in our study were cysts (45.9 % of subjects) and ear, nose, and throat (ENT) lesions (24.8 %) followed by stroke lesions (6.6 %) and neoplasms (3.8 %). There were 472 incidental findings that lacked clinical significance (group 2), and 22 incidental findings that required follow-up evaluation (group 3). Incidental findings on brain MRIs were commonly observed in this cohort of elderly subjects, but clinical follow-up was rarely indicated.


Assuntos
Encéfalo/diagnóstico por imagem , Achados Incidentais , Imageamento por Ressonância Magnética , Idoso , Encefalopatias/diagnóstico por imagem , Encefalopatias/epidemiologia , Feminino , Seguimentos , Humanos , Imageamento Tridimensional , Masculino , Prevalência , Estudos Prospectivos
18.
PLoS One ; 11(3): e0152614, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27029050

RESUMO

Despite a better understanding of brain language organization into large-scale cortical networks, the underlying white matter (WM) connectivity is still not mastered. Here we combined diffusion tensor imaging (DTI) fiber tracking (FT) and language functional magnetic resonance imaging (fMRI) in twenty healthy subjects to gain new insights into the macroscopic structural connectivity of language. Eight putative WM fascicles for language were probed using a deterministic DTI-FT technique: the arcuate fascicle (AF), superior longitudinal fascicle (SLF), uncinate fascicle (UF), temporo-occipital fascicle, inferior fronto-occipital fascicle (IFOF), middle longitudinal fascicle (MdLF), frontal aslant fascicle and operculopremotor fascicle. Specific measurements (i.e. volume, length, fractional anisotropy) and precise cortical terminations were derived for each WM fascicle within both hemispheres. Connections between these WM fascicles and fMRI activations were studied to determine which WM fascicles are related to language. WM fascicle volumes showed asymmetries: leftward for the AF, temporoparietal segment of SLF and UF, and rightward for the frontoparietal segment of the SLF. The lateralization of the AF, IFOF and MdLF extended to differences in patterns of anatomical connections, which may relate to specific hemispheric abilities. The leftward asymmetry of the AF was correlated to the leftward asymmetry of fMRI activations, suggesting that the lateralization of the AF is a structural substrate of hemispheric language dominance. We found consistent connections between fMRI activations and terminations of the eight WM fascicles, providing a detailed description of the language connectome. WM fascicle terminations were also observed beyond fMRI-confirmed language areas and reached numerous cortical areas involved in different functional brain networks. These findings suggest that the reported WM fascicles are not exclusively involved in language and might be related to other cognitive functions such as visual recognition, spatial attention, executive functions, memory, and processing of emotional and behavioral aspects.


Assuntos
Córtex Cerebral , Conectoma , Imagem de Tensor de Difusão , Idioma , Imageamento por Ressonância Magnética , Substância Branca , Adulto , Córtex Cerebral/diagnóstico por imagem , Córtex Cerebral/fisiologia , Feminino , Humanos , Masculino , Radiografia , Substância Branca/diagnóstico por imagem , Substância Branca/fisiologia
19.
Neurodegener Dis ; 16(3-4): 279-83, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26646220

RESUMO

BACKGROUND: Age-related white matter hyperintensities are frequent incidental findings on T2-weighted brain MRI, and they are evaluated in clinical practice using a visual rating scale. OBJECTIVE: To evaluate inter- and intra-rater agreement in MRI visual evaluations of age-related white matter hyperintensities made by two radiologists with different levels of experience using a visual rating scale. METHODS: Two radiologists of two different levels of experience separately rated age-related white matter hyperintensities in 40 consecutive 3-tesla brain MRI scans using the Fazekas and Schmidt visual rating scale. Ratings were made on axial FLAIR (fluid-attenuated inversion recovery) sequences. Two readings were made by each radiologist. Intra- and inter-rater agreement was statistically determined by using Cohen's weighted kappa analysis. RESULTS: Forty patients (21 females, 19 males; mean age = 57 ± 18.43 years) were included between September and October 2011. Mean values ± SD for visual scores were as follows: periventricular hyperintensities, between 1.175 ± 0.9 and 1.375 ± 0.89; number of deep white matter hyperintensity lesions, between 1.325 ± 1.18 and 1.575 ± 1.15, and extent of deep white matter hyperintensity lesions, between 0.925 ± 0.78 and 1.1 ± 0.74. Intra- and inter-rater agreement was very good (x03BA; values, 0.85-0.91 and 0.80-0.97, respectively) for each of the three visual scale criteria, with significant correlations between ratings (r = 0.95; p < 0.0001) and readings (r = 0.91; p < 0.0001). CONCLUSION: Visual assessment of age-related white matter hyperintensities by radiologists using a visual scale on FLAIR sequence is reproducible. Differences in experience level do not influence readings. Visual scale use is thus justified in common practice.


Assuntos
Envelhecimento/patologia , Encéfalo/diagnóstico por imagem , Imageamento por Ressonância Magnética/métodos , Substância Branca/diagnóstico por imagem , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Encéfalo/patologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Variações Dependentes do Observador , Competência Profissional , Reprodutibilidade dos Testes , Índice de Gravidade de Doença , Substância Branca/patologia , Adulto Jovem
20.
Confl Health ; 9: 16, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25991922

RESUMO

A series of Médecins Sans Frontières projects for irregular migrants over the past decade have consistently documented high rates of 14 physical and sexual trauma, extortion and mental illness amidst severe healthcare, food, and housing limitations. Complex interventions were needed to begin to address illness and barriers to healthcare and to help restore dignity to the most vulnerable women, children and men. Promising interventions included mobile clinics, use of cultural mediators, coordination with migrant-friendly entities and NGOs and integrating advocacy programs and mental health care with medical services. Ongoing interventions, research and coordination are needed to address this neglected humanitarian crisis.

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