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See detailCerebral folate deficiency and CNS inflammatory markers in Alpers disease.
Hasselmann, Oswald; Blau, Nenad; RAMAEKERS, Vincent ULg et al

in Molecular Genetics & Metabolism (2010), 99(1), 58-61

We describe a 3.5-year-old female with Alpers disease with a POLG genotype of p.A467T/p.G848S and with a lethal outcome. Laboratory investigation revealed elevated CSF neopterin, IL-6, IL-8, IFN-gamma ... [more ▼]

We describe a 3.5-year-old female with Alpers disease with a POLG genotype of p.A467T/p.G848S and with a lethal outcome. Laboratory investigation revealed elevated CSF neopterin, IL-6, IL-8, IFN-gamma, reduced CSF 5-methyltetrahydrofolate (5MTHF), and increased serum as well as CSF folate receptor blocking autoantibodies. Treatment with oral Leucovorine (5-formyl-tetrahydrofolate) was initiated at 0.25mg/kg bid, and later increased to 4mg/kg bid. Under treatment CSF levels of 5MTHF, seizure frequency and communicative abilities improved. Over a time span of 17months, CSF levels of IL-6 and IFN-gamma decreased, levels of folate receptor blocking autoantibodies continued to raise, whereas CSF IL-8 remained elevated 1500-fold above normal. The child died without apparent stress at the age of 5.5years. Alpers disease, a neurodegenerative disease usually presents in the first years of life as a progressive encephalopathy with multifocal myoclonic seizures, developmental regression, cortical blindness and early death. The underlying genetic defect has been attributed to mutations of the catalytic subunit of the mitochondrial DNA polymerase-gamma leading to an organ-specific mitochondrial DNA depletion syndrome with reduced activity of respiratory chain enzyme complexes in the brain and the liver. A curative therapy is not available. This case report of Alpers disease provides new insights into the pathophysiology of Alpers disease, where mitochondrial dysfunction in conjunction with inflammatory cytokines and blocking folate receptor autoantibodies may lead to a secondary cerebral folate deficiency syndrome. The treatment of the latter provides relief to the patient without stopping the underlying disease. [less ▲]

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See detailCerebral folate deficiency with developmental delay, autism, and response to folinic acid
Moretti, P.; Sahoo, T.; Hyland, K. et al

in Neurology (2005), 64(6), 1088-1090

The authors describe a 6-year-old girl with developmental delay, psychomotor regression, seizures, mental retardation, and autistic features associated with low CSF levels of 5-methyltetrahydrofolate, the ... [more ▼]

The authors describe a 6-year-old girl with developmental delay, psychomotor regression, seizures, mental retardation, and autistic features associated with low CSF levels of 5-methyltetrahydrofolate, the biologically active form of folates in CSF and blood. Folate and B12 levels were normal in peripheral tissues, suggesting cerebral Mate deficiency. Treatment with folinic acid corrected CSF abnormalities and improved motor skills. Copyright © 2005 by AAN Enterprises, Inc. [less ▲]

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See detailCerebral functional connectivity periodically (de)synchronizes with anatomical constraints
Liegeois, Raphaël ULg; Ziegler, Erik; Bahri, Mohamed Ali ULg et al

in Brain Structure and Function (2015)

This paper studies the link between resting-state functional connectivity (FC), measured by the correlations of the fMRI BOLD time courses, and structural connectivity (SC), estimated through fiber ... [more ▼]

This paper studies the link between resting-state functional connectivity (FC), measured by the correlations of the fMRI BOLD time courses, and structural connectivity (SC), estimated through fiber tractography. Instead of a static analysis based on the correlation between SC and the FC averaged over the entire fMRI time series, we propose a dynamic analysis, based on the time evolution of the correlation between SC and a suitably windowed FC. Assessing the statistical significance of the time series against random phase permutations, our data show a pronounced peak of significance for time window widths around 20-30 TR (40-60 sec). Using the appropriate window width, we show that FC patterns oscillate between phases of high modularity, primarily shaped by anatomy, and phases of low modularity, primarily shaped by inter-network connectivity. Building upon recent results in dynamic FC, this emphasizes the potential role of SC as a transitory architecture between different highly connected resting state FC patterns. Finally, we show that networks implied in consciousness-related processes, such as the default mode network (DMN), contribute more to these brain-level fluctuations compared to other networks, such as the motor or somatosensory networks. This suggests that the fluctuations between FC and SC are capturing mind-wandering effects. [less ▲]

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See detailCerebral functional connectivity periodically (de)synchronizes with anatomical constraints
Liegeois, Raphaël ULg; Sepulchre, Rodolphe ULg; LAUREYS, Steven ULg

E-print/Working paper (2014)

This paper studies the link between resting-state functional connectivity (FC), measured by the correlations of the fMRI BOLD time courses, and structural connectivity (SC), estimated through fiber ... [more ▼]

This paper studies the link between resting-state functional connectivity (FC), measured by the correlations of the fMRI BOLD time courses, and structural connectivity (SC), estimated through fiber tractography. Instead of a static analysis based on the correlation between SC and the FC averaged over the entire fMRI time series, we propose a dynamic analysis, based on the time evolution of the correlation between SC and a suitably windowed FC. Assessing the statistical significance of the time series against random phase permutations, our data show a pronounced peak of significance for time window widths around 20-30 TR (40-60 sec). Using the appropriate window width, we show that FC patterns oscillate between phases of high modularity, primarily shaped by anatomy, and phases of low modularity, primarily shaped by inter-network connectivity. Building upon recent results in dynamic FC, this emphasizes the potential role of SC as a transitory architecture between different highly connected resting state FC patterns. Finally, we show that networks implied in consciousness-related processes, such as the default mode network (DMN), contribute more to these brain-level fluctuations compared to other networks, such as the motor or somatosensory networks. This suggests that the fluctuations between FC and SC are capturing mind-wandering effects. [less ▲]

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See detailCerebral functional segregation and integration during human sleep
Maquet, Pierre ULg; Perrin, Fabien; Laureys, Steven ULg et al

in Luppi, Pierre-Herve (Ed.) Sleep: Circuits and Functions (2004)

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See detailCerebral Glucose Utilization During Sleep in Landau-Kleffner Syndrome: A Pet Study
Maquet, Pierre ULg; Hirsch, E.; Dive, Dominique ULg et al

in Epilepsia (1990), 31(6, Nov-Dec), 778-83

Three right-handed male children (aged 5, 6, and 11 years) with signs, symptoms and/or history of the syndrome of acquired aphasia-epilepsy (Landau-Kleffner syndrome) were studied during drug-induced ... [more ▼]

Three right-handed male children (aged 5, 6, and 11 years) with signs, symptoms and/or history of the syndrome of acquired aphasia-epilepsy (Landau-Kleffner syndrome) were studied during drug-induced, electroencephalographically (EEG)-monitored sleep by positron-emission tomography (PET) and the [18F]fluorodeoxyglucose (FDG) method. Our data demonstrate that in Landau-Kleffner syndrome, cerebral glucose utilization is not normal during sleep. The metabolic pattern varied between the children but the metabolic disturbances always predominated over the temporal lobes. They were right-sided, left-sided, or bilateral. In the two first patients, EEG recordings showed continuous spike-and-wave discharges during sleep and a right-greater-than-left asymmetry was observed in temporal areas. In patient 1, the asymmetry was associated with a relative increase of glucose utilization of the right posterior temporal region. In patient 2, the glucose utilization was relatively decreased in the left anterotemporal and left perisylvian regions. In patient 3, the sleep EEG showed no discharge and no significant asymmetry was observed; however, glucose utilization of both temporal lobes was decreased. Lower metabolic rates in subcortical structures than in cortex were also noted in the three children. This metabolic pattern may be related to the maturation of the central nervous system (CNS). [less ▲]

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See detailCerebral Glucose Utilization During Sleep-Wake Cycle in Man Determined by Positron Emission Tomography and [18f]2-Fluoro-2-Deoxy-D-Glucose Method
Maquet, Pierre ULg; Dive, Dominique ULg; Salmon, Eric ULg et al

in Brain Research (1990), 513(1), 136-43

Using the [18F]fluorodeoxyglucose method and positron emission tomography, we studied cerebral glucose utilization during sleep and wakefulness in 11 young normal subjects. Each of them was studied at ... [more ▼]

Using the [18F]fluorodeoxyglucose method and positron emission tomography, we studied cerebral glucose utilization during sleep and wakefulness in 11 young normal subjects. Each of them was studied at least thrice: during wakefulness, slow wave sleep (SWS) and rapid eye movement sleep (REMS), at 1 week intervals. Four stage 3-4 SWS and 4 REMS fulfilled the steady state conditions of the model. The control population consisted of 9 normal age-matched subjects studied twice during wakefulness at, at least, 1 week intervals. Under these conditions, the average difference between the first and the second cerebral glucose metabolic rates (CMRGlu was: -7.91 +/- 15.46%, which does not differ significantly from zero (P = 0.13). During SWS, a significant decrease in CMRGlu was observed as compared to wakefulness (mean difference: -43.80 +/- 14.10%, P less than 0.01). All brain regions were equally affected but thalamic nuclei had significantly lower glucose utilization than the average cortex. During REMS, the CMRGlu were as high as during wakefulness (mean difference: 4.30 +/- 7.40%, P = 0.35). The metabolic pattern during REMS appeared more heterogeneous than at wake. An activation of left temporal and occipital areas is suggested. It is hypothetized that energy requirements for maintaining membrane polarity are reduced during SWS because of a decreased rate of synaptic events. During REMS, cerebral glucose utilization is similar to that of wakefulness, presumably because of reactivated neurotransmission and increased need for ion gradients maintenance. [less ▲]

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See detailCerebral Glucose Utilization During Stage 2 Sleep in Man
Maquet, Pierre ULg; Dive, Dominique ULg; Salmon, Eric ULg et al

in Brain Research (1992), 571(1), 149-53

Using [18F]fluorodeoxyglucose method and positron emission tomography, we performed paired determinations of the cerebral glucose utilization at one week intervals during sleep and wakefulness, in 12 ... [more ▼]

Using [18F]fluorodeoxyglucose method and positron emission tomography, we performed paired determinations of the cerebral glucose utilization at one week intervals during sleep and wakefulness, in 12 young normal subjects. During 6 of 28 sleep runs, a stable stage 2 SWS was observed that fulfilled the steady-state conditions of the model. The cerebral glucose utilization during stage 2 SWS was lower than during wakefulness, but the variation did not significantly differ from zero (mean variation: -11.5 +/- 25.57%, P = 0.28). The analysis of 89 regions of interest showed that glucose metabolism differed significantly from that observed at wake in 6 brain regions, among them both thalamic nuclei. We conclude that the brain energy metabolism is not homogeneous throughout all the stages of non-REMS but decreases from stage 2 SWS to deep SWS; we suggest that a low thalamic glucose metabolism is a metabolic feature common to both stage 2 and deep SWS, reflecting the inhibitory processes observed in the thalamus during these stages of sleep. Stage 2 SWS might protect the stability of sleep by insulating the subject from the environment and might be a prerequisite to the full development of other phases of sleep, especially deep SWS. [less ▲]

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See detailCerebral Grafts
Martin, Didier ULg

Scientific conference (1993, July)

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See detailCerebral hyperperfusion following episodes of bradycardia in the preterm infant
RAMAEKERS, Vincent ULg; Casaer, P.; Daniels, H.

in Early human development (1993), 34(3), 199-208

The alterations in cerebral hemodynamics during and following 39 episodes with bradycardia of different severity have been studied by analysis of Doppler flow velocity waveforms amongst 16 stable preterm ... [more ▼]

The alterations in cerebral hemodynamics during and following 39 episodes with bradycardia of different severity have been studied by analysis of Doppler flow velocity waveforms amongst 16 stable preterm infants (range of conceptional age at the time of study 33-39 weeks; weight 1730-2820 g). Each episode with bradycardia has been classified as mild on seven occasions (heart rate between 100-120 beats/min), moderate on 15 occasions (80-100), or severe on 17 occasions (heart rate below 80) Depending on the severity of the bradycardia, the time-averaged mean flow velocity (V) could decrease by 80% below the preexistent baseline value and the end-diastolic velocity (D) dropped towards the zero line, whereas peak systolic velocities did not change The magnitude of the percentage decrease of V correlated positively with the severity of bradycardia, indicating a progressive decline of cerebral blood flow (CBF). Following bradycardia, V could increase up to 75% above the preexistent baseline value. Simultaneously, an increase of mean arterial blood pressure and D could be documented. Peak systolic velocities remained unaltered. The magnitude of the percentage increase of V following bradycardia depended both on the severity of bradycardia as well as on the drop in transcutaneous oxygen during the preceding bradycardia. Interpretation of these findings suggested that the transient cerebral hyperperfusion following bradycardia compensates for the hypoxic-ischemic episode, sustained during the preceding epoch of apnea and bradycardia. [less ▲]

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See detailCerebral ischemic accidents in young patients, less than 45 years of age
Franck, Georges; Doyen, P.; Grisar, Thierry ULg et al

in Semaine des Hôpitaux de Paris. Thérapeutique (1983), 59(37-38), 2642-2644

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See detailThe cerebral metabolic correlates of episodic autobiographical memory in amnestic Mild Cognitive Impairment
Bastin, Christine ULg; Feyers, Dorothée ULg; Jedidi, Haroun ULg et al

in Proceedings of the 5th International Conference on Memory (2011)

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See detailCerebral metabolic correlates of four dementia scales in Alzheimer's disease
Salmon, Eric ULg; Lespagnard, Solange ULg; Marique, Patricia et al

in Journal of Neurology (2005), 252(3), 283-290

Different scales can be used to evaluate dementia severity in Alzheimers disease (AD). They do assess different cognitive or functional abilities, but their global scores are frequently in mutual ... [more ▼]

Different scales can be used to evaluate dementia severity in Alzheimers disease (AD). They do assess different cognitive or functional abilities, but their global scores are frequently in mutual correlation. Functional imaging provides an objective method for the staging of dementia severity. Positron emission tomography was used to assess the relationship between brain metabolism and four dementia scales that reflect a patients global cognitive abilities (mini mental state), caregivers evaluation of cognitive impairment (newly designed scale), daily living functioning (instrumental activities of daily living) and global dementia (clinical dementia rating). We wondered whether different clinical dementia scales would be related to severity of metabolic impairment in the same brain regions, and might reflect impairment of common cognitive processes. 225 patients with probable AD were recruited in a prospective multicentre European study. All clinical scales were related to brain metabolism in associative temporal, parietal or frontal areas. A factorial analysis demonstrated that all scales could be classified in a single factor. That factor was highly correlated to decrease of cerebral activity in bilateral parietal and temporal cortices, precuneus, and left middle frontal gyrus. This finding suggests that global scores for all scales provided similar information on the neural substrate of dementia severity. Capitalizing on the neuroimaging literature, dementia severity reflected by reduced metabolism in posterior and frontal associative areas in AD might be related to a decrease of controlled processes. [less ▲]

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See detailCerebral metabolism before and after external trigeminal nerve stimulation in episodic migraine
MAGIS, Delphine ULg; D'Ostilio, Kevin ULg; Thibaut, Aurore ULg et al

in Cephalalgia : An International Journal of Headache (2016)

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See detailCerebral metabolism during vegetative state and after recovery to consciousness
Laureys, Steven ULg; Lemaire, Christian ULg; Maquet, Pierre ULg et al

in Journal of Neurology, Neurosurgery & Psychiatry (1999), 67(1), 121-122

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See detailCerebral Monitoring Devices: What We Pay For
BONHOMME, Vincent ULg; Hans, Pol ULg

in Acta Anaesthesiologica Belgica (2006), 57(4), 419-28

view paper, the authors analyse advantages, pitfalls and economical considerations related to depth of anaesthesia monitoring. They first describe the most widely distributed monitors in Europe, and the ... [more ▼]

view paper, the authors analyse advantages, pitfalls and economical considerations related to depth of anaesthesia monitoring. They first describe the most widely distributed monitors in Europe, and the physiological basis of each index. The optimal use of those monitors and their demonstrated clinical benefits are detailed, as well as the circumstances that can lead to erroneous information or interpretation. Knowledge of patients and practitioners, as well as beliefs and expectations regarding depth of anaesthesia monitoring are discussed. Finally, the authors give their own opinion regarding the use of depth of anaesthesia monitoring, according to clinical benefit and economical considerations. [less ▲]

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See detailCerebral processing in the minimally conscious state
Laureys, Steven ULg; Perrin, Fabien; Faymonville, Marie ULg et al

in Neurology (2004), 63(5), 916-918

We studied a patient in a minimally conscious state using PET and cognitive evoked potentials. Cerebral metabolism was below half of normal values. Auditory stimuli with emotional valence ( infant cries ... [more ▼]

We studied a patient in a minimally conscious state using PET and cognitive evoked potentials. Cerebral metabolism was below half of normal values. Auditory stimuli with emotional valence ( infant cries and the patient's own name) induced a much more widespread activation than did meaningless noise; the activation pattern was comparable with that previously obtained in controls. Cognitive potentials showed preserved P300 responses to the patient's own name. [less ▲]

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See detailCerebral processing of auditory and noxious stimuli in severely brain injured patients: Differences between VS and MCS
Boly, Mélanie ULg; Faymonville, Marie-Elisabeth ULg; Peigneux, Philippe ULg et al

in Neuropsychological Rehabilitation (2005), 15(3-4, Jul-Sep), 283-289

We review cerebral processing of auditory and noxious stimuli in minimally conscious state (MCS) and vegetative state (VS) patients. In contrast with limited brain activation found in VS patients, MCS ... [more ▼]

We review cerebral processing of auditory and noxious stimuli in minimally conscious state (MCS) and vegetative state (VS) patients. In contrast with limited brain activation found in VS patients, MCS patients show activation similar to controls in response to auditory, emotional and noxious stimuli. Despite an apparent clinical similarity between MCS and VS patients, functional imaging data show striking differences in cortical segregation and integration between these two conditions. However, in the absence of a generally accepted neural correlate of consciousness as measured by functional neuroirnaging, clinical assessment remains the gold standard for the evaluation and management of severely brain damaged patients. [less ▲]

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