References of "Salmon, Eric"
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See detailNeural bases of subsequent forgetting in young and older adults
François, Sarah ULiege; Angel, Lucie; Salmon, Eric ULiege et al

Poster (2016, March 17)

Objectives Using functional MRI, we looked into the age-related difference in the neural underpinnings of subsequent forgetting - cerebral activation at encoding for items that are later forgotten ... [more ▼]

Objectives Using functional MRI, we looked into the age-related difference in the neural underpinnings of subsequent forgetting - cerebral activation at encoding for items that are later forgotten. Methods In an MRI scanner, during an incidental encoding phase, participants (20 young and 19 older adults) were presented with black-and-white drawings of objects. They were instructed to perform a size judgement on the depicted objects. Then, still in the scanner, the volunteers' memory for the objects was tested by showing them pictures shown previously along with new ones and asking them to make a Remember/Know/New judgement. Results Behaviourally, older participants showed decreased recollection, but intact familiarity at recognition. In an event-related design (SPM8), we compared cerebral areas activated at encoding for items subsequently forgotten compared to those leading to recollection (p<.001 uncorrected). In both groups, a pattern of activation consistent with the default-mode network (DMN) was found. Furthermore, results pointed out to additional activations in the frontoparietal control network in older adults. Also, contrasting activations for items subsequently forgotten with those leading to familiarity revealed activations in DMN areas. In young adults, these activations were limited to the posterior cingulate cortex. Conclusions The forgetting of information appears to be associated with a higher recruitment of the DMN, which might reflect disengagement from encoding-supportive processes, both in young and older participants. Moreover, the additional fronto-parietal activity found in the older group could indicate that their failure to recollect the pictures was related to inefficient encoding mechanisms, in addition to disengagement from the task. [less ▲]

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See detailEVALUATION OF SV2Alox/Cre TRANSGENIC MICE USING [18F]UCB-H IN VITRO AUTORADIOGRAPHY
Serrano Navacerrada, Maria Elisa ULiege; Becker, Guillaume ULiege; MENTEN, Catherine ULiege et al

Poster (2016, March 09)

Introduction Epilepsy is one of the commonest neurological disorders [1]. Antiepileptic drugs mainly target the SV2A protein [2] but its actual role is still largely unknown. [18F]UCB-H was developed to ... [more ▼]

Introduction Epilepsy is one of the commonest neurological disorders [1]. Antiepileptic drugs mainly target the SV2A protein [2] but its actual role is still largely unknown. [18F]UCB-H was developed to study in vivo SV2A brain proteins [3, 4]. The present pilot study was undertaken to evaluate for the first time in vivo in rats SV2A expression in the Kaïnic Acid (KA) epilepsy model [5]. Although this model is well studied in mice, few reports were devoted to rats. Imaging-wise, rats are very interesting thanks to a bigger brain size (reduction of the partial volume effect). Methods Three male Sprague-Dawley were used, one injected with saline and two with multiple KA injections (3 x 5mg/kg) [6]. 75 days later, when spontaneous seizures started to appear, microPET (Focus 120 ) was performed under isoflurane anesthesia (2.5-3 % in air) for 1 hour with [18F]UCB-H (41 ± 5 MBq IV tail vein) followed by MRI (9.4T Agilent, anatomical T2). Coregistration was done with PMOD 3.6 software. Data were expressed as SUV and areas under the curve were calculated for the different regions. Results [18F]UCB-H microPET images showed an important reduction (20-30%) for SV2A after KA injections mainly localized in amygdala, hippocampus, lateral parietal association cortex and cingulate cortex. The rest of the brain was globally unchanged. MRI revealed atrophy and inflammation in amygdala and hippocampus. Conclusions These preliminary results obtained in KA treated rats showed that [18F]UCB-H was able to detect important modifications for SV2A in relevant regions for epilepsy and appears as a valuable tool to follow in vivo SV2A through longitudinal studies. KA model in rats deserves for further development and validation as a tool for the study of epilepsy. [less ▲]

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See detailIn vivo evaluation of [18F]UCB-H binding at SV2A protein, through a new and efficient radiosynthesis of [18F]UCB-H.
Becker, Guillaume ULiege; Warnier, C; Serrano Navacerrada, Maria Elisa ULiege et al

Poster (2016, March 08)

Background: [18F]UCB-H is a validated radiotracer with a high affinity for the synaptic vesicle glycoprotein 2A (SV2A), known as the binding site of the antiepileptic drug levetiracetam [1, 2]. The major ... [more ▼]

Background: [18F]UCB-H is a validated radiotracer with a high affinity for the synaptic vesicle glycoprotein 2A (SV2A), known as the binding site of the antiepileptic drug levetiracetam [1, 2]. The major drawback of [18F]UCB-H was a long, multi-step radiosynthesis with limited yield of radiotracer [3]. We provide here in vivo evaluation of a new efficient single-step radiosynthesis of [18F]UCB-H, that allows us to highlight the role of the enantio-selectivity while targeting SV2A. Then, we synthetized and radiolabeled the major metabolite, namely [18F]UCB-H-N-oxyde, and investigated its impact on rat brain PET images. Methods: [18F]UCB-H was produced with a simple, one-step production strategy which consisted in radiolabeling an enantiomerically pure (S- or R-) N-heteroaryliodonium precursor [4]. 5 Sprague-Dawley (SD) rats underwent 1 dynamic PET scan (60 minutes) with each enantiomer and a third one with the racemic mixture. We used a population-based input function (PBIF) to quantify [18F]UCB-H binding with Logan graphical analysis. [18F]UCB-H-N-oxyde was produced by a direct oxidation with a large excess of pure m-CPBA in Et2O. 5 SD rats underwent 1 dynamic PET scan (60 minutes) with this radiosynthetic [18F]UCB-H-N-oxyde. Results: The radiosynthesis lasted 60 min and afforded a 34 ± 2% radiochemical yield, non-corrected for decay, with a high specific activity (820 ± 180 GBq/µmol). Time activity curves showed higher values for the [18F]UCB-H compared to both the S-[18F]UCB-H and the racemic. Distribution volume (Vt) of the [18F]UCB-H, measured with the PBIF were consistent with previous study [2]. Analysis of [18F]UCB-H-N-oxyde PET images confirmed the absence of Blood-Brain-Barrier crossing. Conclusions: This new [18F]UCB-H radiosynthesis allows us to reach high specific activities. In vivo results are consistent with previous work and emphasize the need of high enantiomeric purity to reach accurate quantitative values of radiotracer binding. The use of a PBIF to quantify [18F]UCB-H binding in the rat brain is reliable and afford longitudinal study. At the end, our study demonstrated that [18F]UCB-H fulfils an important criterion for PET radiopharmaceuticals with the lack of troublesome brain radiometabolites. [less ▲]

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See detailSuccessful episodic memory encoding in ageing: an fMRI study
François, Sarah ULiege; Angel, Lucie; Salmon, Eric ULiege et al

Poster (2016, January 25)

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See detailPrevalence of vasculare risk factors in different stages of prodromal Alzheimer’s disease and its influence on cognitive decline
Bos, I.; Vos, S.; Frölich, L. et al

in Alzheimer's & Dementia : The Journal of the Alzheimer's Association (2016), 12(7), 1059-1061

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See detailDisrupted interaction between memory and self in patients with Alzheimer’s disease
Genon, Sarah ULiege; Salmon, Eric ULiege; Collette, Fabienne ULiege et al

in Proceedings of the 6th International Conference on Memory (2016)

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See detailVolumetric brain MRI measurements in a retrospective Belgian multi-centr MRI biomarker study in dementia - REMEMBER
Niemantsverdriet; Smeets, D.; Bastin, Christine ULiege et al

in Acta Neurologica Belgica (2016)

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See detailCorrelation between resting state fMRI total neuronal activity and PET metabolism in healthy controls and patients with disorders of consciousness
Soddu, Andrea ULiege; Gomez, Francisco; Heine, Lizette ULiege et al

in Brain and Behavior (2016), 6(1), 1-15

Introduction: The mildly invasive 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) is a well-established imaging technique to measure ‘resting state’ cerebral metabolism. This technique made ... [more ▼]

Introduction: The mildly invasive 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) is a well-established imaging technique to measure ‘resting state’ cerebral metabolism. This technique made it possible to assess changes in metabolic activity in clinical applications, such as the study of severe brain injury and disorders of consciousness. Objective: We assessed the possi- bility of creating functional MRI activity maps, which could estimate the rela- tive levels of activity in FDG-PET cerebral metabolic maps. If no metabolic absolute measures can be extracted, our approach may still be of clinical use in centers without access to FDG-PET. It also overcomes the problem of recogniz- ing individual networks of independent component selection in functional mag- netic resonance imaging (fMRI) resting state analysis. Methods: We extracted resting state fMRI functional connectivity maps using independent component analysis and combined only components of neuronal origin. To assess neu- ronality of components a classification based on support vector machine (SVM) was used. We compared the generated maps with the FDG-PET maps in 16 healthy controls, 11 vegetative state/unresponsive wakefulness syndrome patients and four locked-in patients. Results: The results show a significant similarity with q = 0.75  0.05 for healthy controls and q = 0.58  0.09 for vegetative state/unresponsive wakefulness syndrome patients between the FDG- PET and the fMRI based maps. FDG-PET, fMRI neuronal maps, and the conjunction analysis show decreases in frontoparietal and medial regions in vegetative patients with respect to controls. Subsequent analysis in locked-in syndrome patients produced also consistent maps with healthy controls. Conclusions: The constructed resting state fMRI functional connectivity map points toward the possibility for fMRI resting state to estimate relative levels of activity in a metabolic map. [less ▲]

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See detailRelationship between grey matter integrity and executive abilities in aging
Manard, Marine ULiege; Bahri, Mohamed Ali ULiege; Salmon, Eric ULiege et al

in Brain Research (2016), 1642

This cross-sectional study was designed to investigate grey matter changes that occur in healthy aging and the relationship between grey matter characteristics and executive functioning. Thirty-six young ... [more ▼]

This cross-sectional study was designed to investigate grey matter changes that occur in healthy aging and the relationship between grey matter characteristics and executive functioning. Thirty-six young adults (18 to 30 years old) and 43 seniors (60 to 75 years old) were included. A general executive score was derived from a large battery of neuropsychological tests assessing three major aspects of executive functioning (inhibition, updating and shifting). Age-related grey matter changes were investigated by comparing young and older adults using voxel-based morphometry and voxel-based cortical thickness methods. A widespread difference in grey matter volume was found across many brain regions, whereas cortical thinning was mainly restricted to central areas. Multivariate analyses showed age-related changes in relatively similar brain regions to the respective univariate analyses but appeared more limited. Finally, in the older adult sample, a significant relationship between global executive performance and decreased grey matter volume in anterior (i.e. frontal, insular and cingulate cortex) but also some posterior brain areas (i.e. temporal and parietal cortices) as well as subcortical structures was observed. Results of this study highlight the distribution of age-related effects on grey matter volume and show that cortical atrophy does not appear primarily in “frontal” brain regions. From a cognitive viewpoint, age-related executive functioning seems to be related to grey matter volume but not to cortical thickness. Therefore, our results also highlight the influence of methodological aspects (from preprocessing to statistical analysis) on the pattern of results, which could explain the lack of consensus in literature. [less ▲]

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See detailNeural correlates of successful memory retrieval in aging: Do executive functioning and task difficulty matter?
Angel, Lucie; Bastin, Christine ULiege; Genon, Sarah ULiege et al

in Brain Research (2016), 1631

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See detailImpact du format du test sur la recollection et la familiarité dans le vieillissement normal et le trouble cognitif léger de type amnésique
Simon, Jessica ULiege; Gilsoul, Jessica ULiege; SALMON, Eric ULiege et al

Conference (2015, December 04)

Les tâches de reconnaissance à choix-forcé et oui/non ont largement été utilisées dans l’évaluation de la mémoire. Selon Norman et O’Reilly (2003), le format oui/non ferait davantage intervenir la ... [more ▼]

Les tâches de reconnaissance à choix-forcé et oui/non ont largement été utilisées dans l’évaluation de la mémoire. Selon Norman et O’Reilly (2003), le format oui/non ferait davantage intervenir la recollection alors que le format à choix-forcé favoriserait la comparaison du sentiment de familiarité associé à chaque item et la sélection du plus familier. L’objectif de cette étude est d’explorer l’impact du format du test sur la recollection et la familiarité au travers du vieillissement normal et pathologique. Septante participants jeunes (18 - 30 ans), 65 participants jeunes-âgés (55 - 69 ans), 53 participants âgés-âgés (70-85 ans) et 13 patients présentant un trouble cognitif léger amnésique (55-82 ans) ont réalisé deux tâches de reconnaissance. Pour chaque tâche, lors de l’encodage, nous avons présenté, à deux reprises, 25 images à mémoriser. Dans la tâche de reconnaissance à choix forcé, les participants devaient reconnaitre parmi trois images très semblables celle qui a été vue précédemment. Dans la tâche de reconnaissance oui/non, les items étaient présentés successivement et les participants devaient reconnaitre ceux présentés à l’encodage. Pour chaque item reconnu, les participants devaient fournir un jugement Remember/Know/Guess. Les ANOVA Groupe x Format à mesures répétées sur la dernière variable (p<0,05) ont révélé que les jeunes avaient de meilleures performances en reconnaissance (score d’) que les jeunes-âgés, qui ont eux-mêmes de meilleures performances que les âgés-âgés et les patients. En outre, les jeunes utilisent plus souvent le sentiment de familiarité pour reconnaître les images étudiées que les participants âgés et les patients. De plus, les participants jeunes-âgés utilisent plus souvent la familiarité que les participants âgés-âgés, alors qu’il n’y a pas de différence entre ceux-ci et les patients. Cependant, les fausses alarmes associées à la familiarité augmentent progressivement dans le vieillissement et la pathologie. L’utilisation de la recollection est progressivement réduite avec l’âge et altérée dans la pathologie. Enfin, les jeunes tendent à utiliser plus souvent la recollection dans la tâche à choix-forcé (p=0,055), alors qu’il n’y a pas de différence pour les autres groupes. Tous ces résultats suggèrent que le vieillissement normal s’accompagne d’un déclin progressif de la recollection et de la familiarité. Dans le vieillissement pathologique, on observe des performances similaires au groupe le plus âgé en reconnaissance malgré un déficit de recollection. Les patients utilisent la familiarité autant que les deux groupes âgés bien que les taux de fausses alarmes soient plus importants, suggérant une utilisation privilégiée mais inadéquate de ce processus. [less ▲]

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See detailThe neural basis of proactive and reactive control processes in normal aging.
Collette, Fabienne ULiege; Manard, Marine ULiege; François, Sarah ULiege et al

Conference (2015, September 19)

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See detailThe impact of ageing on episodic memory encoding: an fMRI study
François, Sarah ULiege; Angel, Lucie; SALMON, Eric ULiege et al

Poster (2015, September 04)

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See detailEVALUATION OF SV2Alox/Cre TRANSGENIC MOUSE USING [18F]UCB-H IN IN VITRO AUTORADIOGRAPHY
Serrano Navacerrada, Maria Elisa ULiege; Becker, Guillaume ULiege; MENTEN, Catherine ULiege et al

Poster (2015, September 04)

Background: SV2A is the most studied isoform of the Synaptic Vesicle 2 proteins, which are involved in the synaptic vesicle trafficking. Interestingly, the SV2A has been identify as the binding site for ... [more ▼]

Background: SV2A is the most studied isoform of the Synaptic Vesicle 2 proteins, which are involved in the synaptic vesicle trafficking. Interestingly, the SV2A has been identify as the binding site for the antiepileptic drug levetiracetam, showing a close relation between the epilepsy, the dysregulation of the SV2A levels and the response to antiepileptic medications. SV2A floxed-mice were developed using a cre-lox technique, leading to a strong decrease of SV2A expression in the CA3 field of the hippocampus. We aim here to validate this model using [18F]UCB-H, a novel PET imaging radiotracer with a nanomolar affinity for human SV2A. Methods: In vitro autoradiography were performed on SV2Alox/Cre+ transgenic mouse brain slices. SV2Alox/Cre- mouse was used as control. To obtain a structural reference, brain slices underwent eosin-haematoxylin staining. Images of both procedures were coregistered using π-PMOD software. Regions of interest (Dentate Gyrus, CA1, CA2 and CA3) were drawn according to a stereotaxic atlas of the mouse brain. Results: Analyses showed significant differences in radiotracer binding (p<0.001) between SV2Alox/Cre+ mouse and SV2Alox/Cre- mouse highlighting an important reduction for the labelling density in Ammon's horn, particularly in CA1, compared to Dentate Gyrus where the diminution was less marked. Conclusions: Here, we used the radiotracer [18F]UCB-H to probe the decreased expression of SV2A protein in the hippocampus of SV2Alox/Cre+ mouse versus SV2Alox/Cre- control mouse. Our results contribute to the validation of the model, and encourage us to proceed with further longitudinal and behavioural studies. [less ▲]

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See detailThe impact of ageing on episodic memory encoding: an fMRI study
François, Sarah ULiege; Angel, Lucie; Salmon, Eric ULiege et al

Poster (2015, May 28)

It is now commonly accepted that a decline in episodic memory is observed with ageing: while recollection processes are impaired, familiarity seems to be relatively preserved (a). Older individuals appear ... [more ▼]

It is now commonly accepted that a decline in episodic memory is observed with ageing: while recollection processes are impaired, familiarity seems to be relatively preserved (a). Older individuals appear to recruit prefrontal areas bilaterally when their encoding is successful, while in young adults this activation is found to be left-lateralized (b). In this study, we were interested in the differences between younger and older participant regarding cerebral activity during encoding depending on whether the item elicited recollection or familiarity during the recognition phase. Twenty young volunteers (aged 19 to 29 years old) and 19 older volunteers (aged 60 to 78 years old) were presented visual stimuli depicting objects. During a first fMRI session, they were asked to make a size judgement about them. Then, in a second phase, the subjects were shown the items previously encountered during the encoding phase, as well as distractors. Participants' task was to determine which one were new and which one were seen earlier. For the latter, they also performed a Remember-Know judgement. Data were analysed using SPM8, with an event design comparing modifications in cerebral activity between the two subjects groups during encoding (1) for the items leading to recollection during the recognition phase compared to those leading to familiarity, and (2) for the items associated with familiarity during the recognition phase compared to those which were not recognized. Results show that older adults display a heightened activity in the right middle frontal gyrus, medial cingulate and paracingulate left gyri as well as in the precuneus, bilaterally when they engage recollection processes. Given that activations in these areas did not correlate with performance, they could be interepreted either as dedifferentiation or as an attempt of the ageing brain to compensate for a less elaborate encoding. However, no increase of activity was associated with familiarity processes in older adults, possibly because they are less demanding regarding attentional resources. (a) Bugaiska, A., Clarys, D., Jarry, C., Taconnat, L., Tapia, G., Vanneste, S., & Isingrini, M. (2007). The effect of aging in recollective experience: the processing speed and executive functioning hypothesis. Consciousness and Cognition, 16(4), 797-808. doi: 10.1016/j.concog.2006.11.007 (b) Duverne, S., Motamedinia, S., & Rugg, M. D. (2009). The relationship between aging, performance, and the neural correlates of successful memory encoding. Cerebral Cortex, 19(3), 733-744. doi:10.1093/cercor/bhn122 [less ▲]

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See detailThe neural bases of proactive and reactive control processes in healthy aging
Manard, Marine ULiege; François, Sarah ULiege; SALMON, Eric ULiege et al

Poster (2015, May 28)

Background. Research on cognitive control suggests an age-related decline in proactive control abilities (an anticipatory form of control) whereas reactive control (consecutive to conflict detection ... [more ▼]

Background. Research on cognitive control suggests an age-related decline in proactive control abilities (an anticipatory form of control) whereas reactive control (consecutive to conflict detection) seems to remain intact [1]. As proactive and reactive control abilities were associated to specific brain networks [2], this study investigated age-related effects on the neural substrates associated to each kind of control. Method. A modified form of the Stroop task was administered to 16 young and 16 older adults in an event-related fMRI experiment. In this version of the Stroop task, three different contexts were created: (1) a mostly congruent context (MC, inducing reactive control) with a majority of congruent items, (2) a mostly incongruent context (MI, inducing proactive control) with mainly interfering items, (3) a neutral context (MN) with mainly neutral items. Preprocessing and statistical analyses were performed with SPM8 (p<.001 uncorrected). Results. Behavioral results (p<0.05) indicated faster processing of interferent items in the MI than MC context in young participants only. With regard to neuroimaging data, the comparison of the two groups showed that the processing of interferent items in the MI context is associated to decreased activity in (mainly right-sided) frontal and temporal areas in the older group. On the contrary, in the MC context, increased activity was observed in bilateral frontal areas for older compared to younger participants. Discussion. Behavioral results confirm that older participants have difficulties with the implementation of proactive control that is associated to decreased brain activity (compared to young participants) in areas underlying Stroop performance. However, the recruitment of supplementary frontal areas we observed in the reactive control condition suggests compensation processes. So, aging seems to differentially affect the neural networks associated to the various kinds of cognitive control. [less ▲]

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