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Mapping the neural patterns that drive human behavior is a key challenge in neuroscience. Even the simplest of our everyday actions stem from the dynamic and complex interplay of multiple neural structures across the central nervous system (CNS). Yet, most neuroimaging research has focused on investigating cerebral mechanisms, while the way the spinal cord accompanies the brain in shaping human behavior has been largely overlooked. Although the recent advent of functional magnetic resonance imaging (fMRI) sequences that can simultaneously target the brain and spinal cord has opened up new avenues for studying these mechanisms at multiple levels of the CNS, research to date has been limited to inferential univariate techniques that cannot fully unveil the intricacies of the underlying neural states. To address this, we propose to go beyond traditional analyses and instead use a data-driven multivariate approach leveraging the dynamic content of cerebro-spinal signals using innovation-driven coactivation patterns (iCAPs). We demonstrate the relevance of this approach in a simultaneous brain-spinal cord fMRI dataset acquired during motor sequence learning (MSL), to highlight how large-scale CNS plasticity underpins rapid improvements in early skill acquisition and slower consolidation after extended practice. Specifically, we uncovered cortical, subcortical and spinal functional networks, which were used to decode the different stages of learning with a high accuracy and, thus, delineate meaningful cerebro-spinal signatures of learning progression. Our results provide compelling evidence that the dynamics of neural signals, paired with a data-driven approach, can be used to disentangle the modular organization of the CNS. While we outline the potential of this framework to probe the neural correlates of motor learning, its versatility makes it broadly applicable to explore the functioning of cerebro-spinal networks in other experimental or pathological conditions.
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Encéfalo , Médula Espinal , Humanos , Encéfalo/diagnóstico por imagen , Encéfalo/fisiología , Médula Espinal/diagnóstico por imagen , Médula Espinal/fisiología , Aprendizaje/fisiología , Imagen por Resonancia Magnética/métodos , NeuroimagenRESUMEN
As a consequence of recent technological advances in the field of functional magnetic resonance imaging (fMRI), results can now be made available in real-time. This allows for novel applications such as online quality assurance of the acquisition, intra-operative fMRI, brain-computer-interfaces, and neurofeedback. To that aim, signal processing algorithms for real-time fMRI must reliably correct signal contaminations due to physiological noise, head motion, and scanner drift. The aim of this study was to compare performance of the commonly used online detrending algorithms exponential moving average (EMA), incremental general linear model (iGLM) and sliding window iGLM (iGLMwindow). For comparison, we also included offline detrending algorithms (i.e., MATLAB's and SPM8's native detrending functions). Additionally, we optimized the EMA control parameter, by assessing the algorithm's performance on a simulated data set with an exhaustive set of realistic experimental design parameters. First, we optimized the free parameters of the online and offline detrending algorithms. Next, using simulated data, we systematically compared the performance of the algorithms with respect to varying levels of Gaussian and colored noise, linear and non-linear drifts, spikes, and step function artifacts. Additionally, using in vivo data from an actual rt-fMRI experiment, we validated our results in a post hoc offline comparison of the different detrending algorithms. Quantitative measures show that all algorithms perform well, even though they are differently affected by the different artifact types. The iGLM approach outperforms the other online algorithms and achieves online detrending performance that is as good as that of offline procedures. These results may guide developers and users of real-time fMRI analyses tools to best account for the problem of signal drifts in real-time fMRI.
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Algoritmos , Artefactos , Encéfalo/fisiología , Procesamiento de Imagen Asistido por Computador/métodos , Imagen por Resonancia Magnética/métodos , Mapeo Encefálico/métodos , HumanosRESUMEN
OBJECTIVE: Essential tremor (ET) represents the most common movement disorder. Drug-resistant ET can benefit from standard stereotactic procedures (deep brain stimulation or radiofrequency thalamotomy) or alternatively minimally invasive high-focused ultrasound or radiosurgery. All aim at same target, thalamic ventro-intermediate nucleus (Vim). METHODS: The study included a cohort of 17 consecutive patients, with ET, treated only with left unilateral stereotactic radiosurgical thalamotomy (SRS-T) between September 2014 and August 2015. The mean time to tremor improvement was 3.32 months (SD 2.7, 0.5-10). Neuroimaging data were collected at baseline (n = 17). Standard tremor scores, including activities of daily living (ADL) and tremor score on treated hand (TSTH), were completed pretherapeutically and 1 year later. We further correlate these scores with baseline inter-connectivity in twenty major large-scale brain networks. RESULTS: We report as predictive three networks, with the interconnected statistically significant clusters: primary motor cortex interconnected with inferior olivary nucleus, bilateral thalamus interconnected with motor cerebellum lobule V2 (ADL), and anterior default-mode network interconnected with Brodmann area 103 (TSTH). For all, more positive pretherapeutic interconnectivity correlated with higher drop in points on the respective scores. Age, disease duration, or time-to-response after SRS-T were not statistically correlated with pretherapeutic brain connectivity measures (P > .05). The same applied to pretherapeutic tremor scores, after using the same methodology described above. CONCLUSIONS: Our findings have clinical implications for predicting clinical response after SRS-T. Here, using pretherapeutic magnetic resonance imaging and data processing without prior hypothesis, we show that pretherapeutic network(s) interconnectivity strength predicts tremor arrest in drug-naïve ET, following stereotactic radiosurgical thalamotomy.
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Temblor Esencial/diagnóstico por imagen , Temblor Esencial/cirugía , Neuroimagen Funcional/métodos , Radiocirugia/métodos , Tálamo/diagnóstico por imagen , Tálamo/cirugía , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Interpretación de Imagen Asistida por Computador , Imagen por Resonancia Magnética/métodos , Masculino , Persona de Mediana Edad , Red Nerviosa/diagnóstico por imagen , Resultado del TratamientoRESUMEN
Infantile spasms syndrome (ISs) is characterized by clinical spasms with ictal electrodecrement, usually occurring before the age of 1 year and frequently associated with cognitive impairment. Etiology is widely heterogeneous, the cause remaining elusive in 40% of patients. We searched for de novo mutations in 10 probands with ISs and their parents using whole-exome sequencing (WES). Patients had neither consanguinity nor family history of epilepsy. Common causes of ISs were excluded by brain magnetic resonance imaging (MRI), metabolic screening, array-comparative genomic hybridization (CGH) and testing for mutations in CDKL5, STXBP1, and for ARX duplications. We found a probably pathogenic mutation in four patients. Missense mutations in SCN2A (p.Leu1342Pro) and KCNQ2 (p.Ala306Thr) were found in two patients with no history of epilepsy before the onset of ISs. The p.Asn107Ser missense mutation of ALG13 had been previously reported in four females with ISs. The fourth mutation was an in-frame deletion (p.Phe110del) in NR2F1, a gene whose mutations cause intellectual disability, epilepsy, and optic atrophy. In addition, we found a possibly pathogenic variant in KIF3C that encodes a kinesin expressed during neural development. Our results confirm that WES improves significantly the diagnosis yield in patients with sporadic ISs.
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Exoma/genética , Espasmos Infantiles/diagnóstico , Espasmos Infantiles/genética , Secuencia de Aminoácidos , Secuencia de Bases , Niño , Preescolar , Secuencia Conservada , Femenino , Humanos , Lactante , Recién Nacido , Masculino , Datos de Secuencia Molecular , Mutación/genética , Embarazo , Análisis de Secuencia de ADN , SíndromeRESUMEN
BACKGROUND: Patients who experience severe brain injuries are at risk of secondary brain damage, because of delayed vasospasm and edema. Traditionally, many of these patients are kept on prolonged bed rest in order to maintain adequate cerebral blood flow, especially in the case of subarachnoid hemorrhage. On the other hand, prolonged bed rest carries important morbidity. There may be a clinical benefit in early mobilization and our hypothesis is that early gradual mobilization is safe in these patients. The aim of this study was to observe and quantify the changes in sympathetic activity, mainly related to stress, and blood pressure in gradual postural changes by the verticalization robot (Erigo®) and after training by a lower body ergometer (MOTOmed-letto®), after prolonged bed rest of minimum 7 days. METHODS: Thirty patients with severe neurological injuries were randomized into 3 groups with different protocols of mobilization: Standard, MOTOmed-letto® or Erigo® protocol. We measured plasma catecholamines, metanephrines and blood pressure before, during and after mobilization. RESULTS: Blood pressure does not show any significant difference between the 3 groups. The analysis of the catecholamines suggests a significant increase in catecholamine production during Standard mobilization with physiotherapists and with MOTOmed-letto® and no changes with Erigo®. CONCLUSIONS: This preliminary prospective randomized study shows that the mobilization of patients with severe brain injuries by means of Erigo® does not increase the production of catecholamines. It means that Erigo® is a well-tolerated method of mobilization and can be considered a safe system of early mobilization of these patients. Further studies are required to validate our conclusions. TRIAL REGISTRATION: The study was registered in the ISRCTN registry with the trial registration number ISRCTN56402432 . Date of registration: 08.03.2016. Retrospectively registered.
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Presión Sanguínea/fisiología , Lesiones Encefálicas/fisiopatología , Lesiones Encefálicas/rehabilitación , Catecolaminas/sangre , Ambulación Precoz , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Masculino , Persona de Mediana Edad , Modalidades de Fisioterapia , Adulto JovenRESUMEN
Recent advances in neurofeedback based on real-time functional magnetic resonance imaging (fMRI) allow for learning to control spatially localized brain activity in the range of millimeters across the entire brain. Real-time fMRI neurofeedback studies have demonstrated the feasibility of self-regulating activation in specific areas that are involved in a variety of functions, such as perception, motor control, language, and emotional processing. In most of these previous studies, participants trained to control activity within one region of interest (ROI). In the present study, we extended the neurofeedback approach by now training healthy participants to control the interhemispheric balance between their left and right visual cortices. This was accomplished by providing feedback based on the difference in activity between a target visual ROI and the corresponding homologue region in the opposite hemisphere. Eight out of 14 participants learned to control the differential feedback signal over the course of 3 neurofeedback training sessions spread over 3 days, i.e., they produced consistent increases in the visual target ROI relative to the opposite visual cortex. Those who learned to control the differential feedback signal were subsequently also able to exert that control in the absence of neurofeedback. Such learning to voluntarily control the balance between cortical areas of the two hemispheres might offer promising rehabilitation approaches for neurological or psychiatric conditions associated with pathological asymmetries in brain activity patterns, such as hemispatial neglect, dyslexia, or mood disorders.
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Lateralidad Funcional/fisiología , Neuroimagen Funcional/métodos , Neurorretroalimentación/fisiología , Corteza Visual/fisiología , Percepción Visual/fisiología , Adulto , Femenino , Humanos , Imagen por Resonancia Magnética , Masculino , Adulto JovenRESUMEN
Little is known about the simultaneous effects of non-pharmacological interventions (NPI) on healthy older adults' behavior and brain plasticity, as measured by psychometric instruments and magnetic resonance imaging (MRI). The purpose of this scoping review was to compile an extensive list of randomized controlled trials published from January 1, 2000, to August 31, 2023, of NPI for mitigating and countervailing age-related physical and cognitive decline and associated cerebral degeneration in healthy elderly populations with a mean age of 55 and over. After inventorying the NPI that met our criteria, we divided them into six classes: single-domain cognitive, multi-domain cognitive, physical aerobic, physical non-aerobic, combined cognitive and physical aerobic, and combined cognitive and physical non-aerobic. The ultimate purpose of these NPI was to enhance individual autonomy and well-being by bolstering functional capacity that might transfer to activities of daily living. The insights from this study can be a starting point for new research and inform social, public health, and economic policies. The PRISMA extension for scoping reviews (PRISMA-ScR) checklist served as the framework for this scoping review, which includes 70 studies. Results indicate that medium- and long-term interventions combining non-aerobic physical exercise and multi-domain cognitive interventions best stimulate neuroplasticity and protect against age-related decline and that outcomes may transfer to activities of daily living.
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OBJECTIVE: Structure-function coupling remains largely unknown in brain disorders. We studied this coupling during interictal epileptic discharges (IEDs), using graph signal processing in temporal lobe epilepsy (TLE). METHODS: We decomposed IEDs of 17 patients on spatial maps, i.e. network harmonics, extracted from a structural connectome. Harmonics were split in smooth maps (long-range interactions reflecting integration) and coarse maps (short-range interactions reflecting segregation) and were used to reconstruct the part of the signal coupled (Xc) and decoupled (Xd) from the structure, respectively. We analysed how Xc and Xd embed the IED energy over time, at global and regional level. RESULTS: For Xc, the energy was smaller than for Xd before the IED onset (p < .001), but became larger around the first IED peak (p < .05, cluster 2, C2). Locally, the ipsilateral mesial regions were significantly coupled to the structure over the whole epoch. The ipsilateral hippocampus increased its coupling during C2 (p < .01). CONCLUSIONS: At whole-brain level, segregation gives way to integrative processes during the IED. Locally, brain regions commonly involved in the TLE epileptogenic network increase their reliance on long-range couplings during IED (C2). SIGNIFICANCE: In TLE, integration mechanisms prevail during the IED and are localized in the ipsilateral mesial temporal regions.
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Epilepsia del Lóbulo Temporal , Epilepsia , Humanos , Electroencefalografía , Lóbulo Temporal , Encéfalo , Imagen por Resonancia MagnéticaRESUMEN
BACKGROUND: A neurocognitive phenotype of post-COVID-19 infection has recently been described that is characterized by a lack of awareness of memory impairment (i.e., anosognosia), altered functional connectivity in the brain's default mode and limbic networks, and an elevated monocyte count. However, the relationship between these cognitive and brain functional connectivity alterations in the chronic phase with the level of cytokines during the acute phase has yet to be identified. AIM: Determine whether acute cytokine type and levels is associated with anosognosia and functional patterns of brain connectivity 6-9 months after infection. METHODS: We analyzed the predictive value of the concentration of acute cytokines (IL-1RA, IL-1ß, IL-6, IL-8, IFNγ, G-CSF, GM-CSF) (cytokine panel by multiplex immunoassay) in the plasma of 39 patients (mean age 59 yrs, 38-78) in relation to their anosognosia scores for memory deficits via stepwise linear regression. Then, associations between the different cytokines and brain functional connectivity patterns were analyzed by MRI and multivariate partial least squares correlations for the whole group. RESULTS: Stepwise regression modeling allowed us to show that acute TNFα levels predicted (R2 = 0.145; ß = -0.38; p = .017) and were associated (r = -0.587; p < .001) with scores of anosognosia for memory deficits observed 6-9 months post-infection. Finally, high TNFα levels were associated with hippocampal, temporal pole, accumbens nucleus, amygdala, and cerebellum connectivity. CONCLUSION: Increased plasma TNFα levels in the acute phase of COVID-19 predict the presence of long-term anosognosia scores and changes in limbic system functional connectivity.
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Agnosia , COVID-19 , Disfunción Cognitiva , Humanos , Agnosia/psicología , Disfunción Cognitiva/etiología , Citocinas , Trastornos de la Memoria , Factor de Necrosis Tumoral alfaRESUMEN
BACKGROUND: Skin manifestations of Tuberous Sclerosis Complex (TSC) are present in more than 90% of patients. Facial angiofibromas (AF) are considered a skin hallmark of TSC. They are responsible for esthetic impact in patients. We aimed at reviewing the data available on the use of rapamycin (sirolimus) and everolimus for the oral or topical treatment of AF and other TSC-related skin changes and reporting our preliminary experience at Angers University Hospital. METHODS: The literature search has been performed in combining the terms "rapamycin", "sirolimus", "everolimus", "tuberous sclerosis complex", "skin" and "trial". We have splited the findings of the literature search into two parts: 1) the value of rapalogs used systemically for extracutaneous purposes and 2) the role of topical rapalogs used specifically for skin lesions. RESULTS: Large clinical trials using rapamycin or everolimus for the treatment of brain, lung or kidney manifestations of TSC unfortunately poorly define the "skin lesion response rate" they report. Conversely, the trials with topical rapamycin demonstrate significant, albeit transient, efficacy on AF size and visibility and acceptable tolerance. Several trials suggest better efficacy in younger patients than in adults. Long-term evaluation (up to 136 weeks) point to sustained response and good local and systemic tolerance. However, maintenance therapy appears to be mandatory to preserve skin response. Other skin changes, especially shagreen fibrotic plaques, hypomelanotic macules and ungual tumors still need far more research. Our experience in 124 patients (children and adults) treated for facial AF at Angers University Hospital showed that about 80% of them had an impressive and sustained response. CONCLUSION: The issues of cost and access to affordable topical rapamycin formulations are critical for the patients even if skin changes do not cause serious harm in the context of TSC. We strongly suggest to improve and standardize the formulation of topical rapamycin, to encourage the pharmaceutical industry for providing commercial products, and the Health systems (social welfare) to reimburse them. © 2022 French Society of Pediatrics. Published by Elsevier Masson SAS. All rights reserved.
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Enfermedades de la Piel , Esclerosis Tuberosa , Adulto , Humanos , Niño , Inhibidores mTOR , Esclerosis Tuberosa/complicaciones , Esclerosis Tuberosa/tratamiento farmacológico , Sirolimus/uso terapéutico , Inmunosupresores/uso terapéutico , Inmunosupresores/efectos adversos , Everolimus/uso terapéutico , Enfermedades de la Piel/tratamiento farmacológico , Enfermedades de la Piel/etiología , Serina-Treonina Quinasas TORRESUMEN
BACKGROUND AND PURPOSE: Early outcome prediction of postanoxic patients in a coma after cardiac arrest proves challenging. Current prognostication relies on multimodal testing, using clinical examination, electrophysiologic testing, biomarkers, and structural MR imaging. While this multimodal prognostication is accurate for predicting poor outcome (ie, death), it is not sensitive enough to identify good outcome (ie, consciousness recovery), thus leaving many patients with indeterminate prognosis. We specifically assessed whether resting-state fMRI provides prognostic information, notably in postanoxic patients in a coma with indeterminate prognosis early after cardiac arrest, specifically for good outcome. MATERIALS AND METHODS: We used resting-state fMRI in a prospective study to compare whole-brain functional connectivity between patients with good and poor outcomes, implementing support vector machine learning. Then, we automatically predicted coma outcome using resting-state fMRI and also compared the prediction based on resting-state fMRI with the outcome prediction based on DWI. RESULTS: Of 17 eligible patients who completed the study procedure (among 351 patients screened), 9 regained consciousness and 8 remained comatose. We found higher functional connectivity in patients recovering consciousness, with greater changes occurring within and between the occipitoparietal and temporofrontal regions. Coma outcome prognostication based on resting-state fMRI machine learning was very accurate, notably for identifying patients with good outcome (accuracy, 94.4%; area under the receiver operating curve, 0.94). Outcome predictors using resting-state fMRI performed significantly better (P < .05) than DWI (accuracy, 60.0%; area under the receiver operating curve, 0.63). CONCLUSIONS: Indeterminate prognosis might lead to major clinical uncertainty and significant variations in life-sustaining treatments. Resting-state fMRI might bridge the gap left in early prognostication of postanoxic patients in a coma by identifying those with both good and poor outcomes.
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Coma/fisiopatología , Imagen por Resonancia Magnética/métodos , Recuperación de la Función/fisiología , Máquina de Vectores de Soporte , Adulto , Anciano , Encéfalo/fisiopatología , Coma/diagnóstico , Coma/etiología , Femenino , Paro Cardíaco/complicaciones , Humanos , Hipoxia/etiología , Masculino , Persona de Mediana Edad , Pronóstico , Estudios ProspectivosRESUMEN
Epileptic networks, defined as brain regions involved in epileptic brain activity, have been mapped by functional connectivity in simultaneous electroencephalography and functional magnetic resonance imaging (EEG-fMRI) recordings. This technique allows to define brain hemodynamic changes, measured by the Blood Oxygen Level Dependent (BOLD) signal, associated to the interictal epileptic discharges (IED), which together with ictal events constitute a signature of epileptic disease. Given the highly time-varying nature of epileptic activity, a dynamic functional connectivity (dFC) analysis of EEG-fMRI data appears particularly suitable, having the potential to identify transitory features of specific connections in epileptic networks. In the present study, we propose a novel method, defined dFC-EEG, that integrates dFC assessed by fMRI with the information recorded by simultaneous scalp EEG, in order to identify the connections characterised by a dynamic profile correlated with the occurrence of IED, forming the dynamic epileptic subnetwork. Ten patients with drug-resistant focal epilepsy were included, with different aetiology and showing a widespread (or multilobar) BOLD activation, defined as involving at least two distinct clusters, located in two different lobes and/or extended to the hemisphere contralateral to the epileptic focus. The epileptic focus was defined from the IED-related BOLD map. Regions involved in the occurrence of interictal epileptic activity; i.e., forming the epileptic network, were identified by a general linear model considering the timecourse of the fMRI-defined focus as main regressor. dFC between these regions was assessed with a sliding-window approach. dFC timecourses were then correlated with the sliding-window variance of the IED signal (VarIED), to identify connections whose dynamics related to the epileptic activity; i.e., the dynamic epileptic subnetwork. As expected, given the very different clinical picture of each individual, the extent of this subnetwork was highly variable across patients, but was but was reduced of at least 30% with respect to the initially identified epileptic network in 9/10 patients. The connections of the dynamic subnetwork were most commonly close to the epileptic focus, as reflected by the laterality index of the subnetwork connections, reported higher than the one within the original epileptic network. Moreover, the correlation between dFC timecourses and VarIED was predominantly positive, suggesting a strengthening of the dynamic subnetwork associated to the occurrence of IED. The integration of dFC and scalp IED offers a more specific description of the epileptic network, identifying connections strongly influenced by IED. These findings could be relevant in the pre-surgical evaluation for the resection or disconnection of the epileptogenic zone and help in reaching a better post-surgical outcome. This would be particularly important for patients characterised by a widespread pathological brain activity which challenges the surgical intervention.
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Epilepsia , Imagen por Resonancia Magnética , Encéfalo/diagnóstico por imagen , Mapeo Encefálico , Electroencefalografía , Epilepsia/diagnóstico por imagen , HumanosRESUMEN
The identification and accurate location of centers of brain activity are vital both in neuro-surgery and brain research. This study aimed to provide a non-invasive, non-contact, accurate, rapid and user-friendly means of producing functional images intraoperatively. To this end a full field Laser Doppler imager was developed and integrated within the surgical microscope and perfusion images of the cortical surface were acquired during awake surgery whilst the patient performed a predetermined task. The regions of brain activity showed a clear signal (10-20% with respect to the baseline) related to the stimulation protocol which lead to intraoperative functional brain maps of strong statistical significance and which correlate well with the preoperative fMRI and intraoperative cortical electro-stimulation. These initial results achieved with a prototype device and wavelet based regressor analysis (the hemodynamic response function being derived from MRI applications) demonstrate the feasibility of LDI as an appropriate technique for intraoperative functional brain imaging.
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Mapeo Encefálico/métodos , Neoplasias Encefálicas/diagnóstico , Neoplasias Encefálicas/cirugía , Cuidados Intraoperatorios/métodos , Flujometría por Láser-Doppler/métodos , Rayos Láser , Cirugía Asistida por Computador/métodos , Adulto , Humanos , Masculino , Resultado del TratamientoRESUMEN
Mutations in the RMND1 gene, causing defects in the mitochondrial respiratory chain, result in a very heterozygous phenotype. Currently there are 36 cases reported in the literature. We report two siblings from a non-consanguineous family who were severely affected by a compound heterozygous RMND1 mutation that had not been described previously and were treated differently for their end-stage renal disease. We summarize all previous published cases and focus on the importance of extrarenal comorbidities in the context of therapeutic decision making (renal replacement therapy) and its ethical relevance.
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Proteínas de Ciclo Celular/genética , Toma de Decisiones Clínicas/ética , Fallo Renal Crónico/genética , Enfermedades Mitocondriales/genética , Hermanos , Resultado Fatal , Femenino , Heterocigoto , Humanos , Fallo Renal Crónico/diagnóstico , Fallo Renal Crónico/terapia , Masculino , Enfermedades Mitocondriales/diagnóstico , Enfermedades Mitocondriales/terapia , Mutación , Fenotipo , Índice de Severidad de la EnfermedadRESUMEN
The understanding of ecosystem services is essential to support sustainable use and preservation of ecosystems. Coralligenous habitats, main contributors of the Mediterranean marine biodiversity, are yet understudied in term of services provided. This study presents an original small-scale approach to investigate the services provided by coralligenous habitats of a French study area consisting of two marine sites (Marseille and Port-Cros sites) in order to cover two contrasted anthropogenic pressure despite the small-scale. Our results are based on the opinions of 43 experts who ranked 15 services in terms of existence and level of importance for human well-being: supporting ecological functions were considered the most important, then provisioning and cultural services. Regulating services were considered uncertain due to a lack of knowledge. The small-scale approach highlighted a need for a referential frame to determine the existence of services (e.g. geographical and temporal scales, benefits and beneficiaries levels).
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Conservación de los Recursos Naturales/métodos , Ecosistema , Alimentos Marinos , Animales , Antozoos , Biodiversidad , Secuestro de Carbono , Ecología , Explotaciones Pesqueras , Francia , Humanos , Entrevistas como Asunto , Mar MediterráneoRESUMEN
BACKGROUND: Effects of beta-amyloid accumulation on neuronal function precede the clinical manifestation of Alzheimer's disease (AD) by years and affect distinct cognitive brain networks. As previous studies suggest a link between beta-amyloid and dysregulation of excitatory and inhibitory neurotransmitters, we aimed to investigate the impact of GABA and glutamate on beta-amyloid related functional connectivity. METHODS: 29 cognitively unimpaired old-aged adults (ageâ¯=â¯70.03⯱â¯5.77â¯years) were administered 11C-Pittsburgh Compound B (PiB) positron-emission tomography (PET), and MRI at 7â¯Tesla (7T) including blood oxygen level dependent (BOLD) functional MRI (fMRI) at rest for measuring static and dynamic functional connectivity. An advanced 7T MR spectroscopic imaging (MRSI) sequence based on the free induction decay acquisition localized by outer volume suppression' (FIDLOVS) technology was used for gray matter specific measures of GABA and glutamate in the posterior cingulate and precuneus (PCP) region. RESULTS: GABA and glutamate MR-spectra indicated significantly higher levels in gray matter than in white matter. A global effect of beta-amyloid on functional connectivity in the frontal, occipital and inferior temporal lobes was observable. Interactive effects of beta-amyloid with gray matter GABA displayed positive PCP connectivity to the frontomedial regions, and the interaction of beta-amyloid with gray matter glutamate indicated positive PCP connectivity to frontal and cerebellar regions. Furthermore, decreased whole-brain but increased fronto-occipital and temporo-parietal dynamic connectivity was found, when GABA interacted with regional beta-amyloid deposits in the amygdala, frontal lobe, hippocampus, insula and striatum. CONCLUSIONS: GABA, and less so glutamate, may moderate beta-amyloid related functional connectivity. Additional research is needed to better characterize their interaction and potential impact on AD.
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Envejecimiento/fisiología , Péptidos beta-Amiloides/metabolismo , Cerebelo/fisiología , Corteza Cerebral/fisiología , Ácido Glutámico/metabolismo , Sustancia Gris/fisiología , Neuroimagen/métodos , Ácido gamma-Aminobutírico/metabolismo , Anciano , Envejecimiento/metabolismo , Compuestos de Anilina , Cerebelo/diagnóstico por imagen , Cerebelo/metabolismo , Corteza Cerebral/diagnóstico por imagen , Corteza Cerebral/metabolismo , Conectoma/métodos , Femenino , Sustancia Gris/diagnóstico por imagen , Sustancia Gris/metabolismo , Humanos , Imagen por Resonancia Magnética/métodos , Espectroscopía de Resonancia Magnética/métodos , Masculino , Tomografía de Emisión de Positrones/métodos , TiazolesRESUMEN
Using Monte Carlo simulations for a semi-infinite medium representing a skeletal muscle tissue, it is demonstrated that the zero- and first-order moments of the power spectrum for a representative pixel of a full-field laser-Doppler imager behave differently from classical laser-Doppler flowmetry. In particular, the zero-order moment has a very low sensitivity to tissue blood volume changes, and it becomes completely insensitive if the probability for a photon to interact with a moving red blood cell is above 0.05. It is shown that the loss in sensitivity is due to the strong forward scatter of the propagating photons in biological tissues (i.e., anisotropy factor g = 0.9). The first-order moment is linearly related to the root mean square of the red blood cell velocity (the Brownian component), and there is also a positive relationship with tissue blood volume. The most common physiological interpretation of the first-order moment is as tissue blood volume times expectation of the blood velocity (in probabilistic terms). In this sense, the use of the first-order moment appears to be a reasonable approach for qualitative real-time blood flow monitoring, but it does not allow us to obtain information on blood velocity or volume independently. Finally, it is shown that the spatial and temporal resolution trade-off imposed by the CMOS detectors, used in full-field laser-Doppler hardware, may lead to measurements that vary oppositely with the underlying physiological quantities. Further improvements on detectors' sampling rate will overcome this limitation.
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Velocidad del Flujo Sanguíneo , Determinación del Volumen Sanguíneo , Flujometría por Láser-Doppler/métodos , Músculo Esquelético/irrigación sanguínea , Eritrocitos , Humanos , Modelos Cardiovasculares , Método de Montecarlo , Fotones , ProbabilidadAsunto(s)
Agenesia del Cuerpo Calloso/diagnóstico por imagen , Encefalopatías/diagnóstico por imagen , Cerebro/diagnóstico por imagen , Quistes/diagnóstico por imagen , Adulto , Agenesia del Cuerpo Calloso/diagnóstico , Encefalopatías/diagnóstico , Corteza Cerebral/anomalías , Corteza Cerebral/anatomía & histología , Quistes/diagnóstico , Femenino , Humanos , Imagen por Resonancia Magnética , Embarazo , Ultrasonografía PrenatalRESUMEN
Pai syndrome is a rare disorder characterized by the association of a midline pericallosal lipoma, median cleft (palate or lip) and cutaneous polyps of the face. Only seven cases have been reported in the medical literature and we are not aware of any previously reported prenatally detected cases. In this article, we present the prenatal ultrasound and magnetic resonance imaging findings of a syndromic pericallosal lipoma with associated anomalies that led to the prenatal diagnosis of Pai syndrome. We underline the impact on parental counseling following prenatal detection of pericallosal lipoma.
Asunto(s)
Neoplasias Encefálicas/diagnóstico , Fisura del Paladar/diagnóstico , Feto/anomalías , Lipoma/diagnóstico , Labio Leporino/diagnóstico , Consejo , Femenino , Humanos , Recién Nacido , Imagen por Resonancia Magnética , Pólipos Nasales/diagnóstico , Pólipos/diagnóstico , Anomalías Cutáneas/diagnóstico , Síndrome , Ultrasonografía PrenatalRESUMEN
Pediatric arterial ischemic stroke (AIS) is little known by pediatricians, as it is rare and difficult to diagnose. Current therapeutic approaches include platelet aggregation inhibitors, anticoagulation using heparin or thrombolysis with rt-PA, and therapeutic abstention in the absence of consensus, in contrast with stroke in adults. We report the case of a 3-year-old child who benefited from intravenous thrombolysis with rt-PA 2h after a major AIS of the anterior and middle left arteries due to embolism from the heart. Neurological progression was marked by a persistent, severe functional deficiency, in spite of the early use of thrombolysis. No hemorrhagic complication occurred. This observation raises the problem of therapeutic indications in childhood AIS and more particularly the question of the use of intravenous thrombolysis. Currently, few studies exist on this subject and only a few case report of children and teenagers having received effective intravenous or intra-arterial thrombolysis further to an AIS are available in the literature. A single study describes 46 cases of children with AIS having received thrombolysis but reports numerous complications. However, the absence of symptomatic hemorrhagic complications is noteworthy. There is currently insufficient evidence to recommend thrombolysis in pediatric AIS; nevertheless it can be proposed in certain rare cases, similar to the observation reported herein.