Similar or Different? The Role of the Ventrolateral Prefrontal Cortex in Similarity Detection

Patients with frontal lobe syndrome can exhibit two types of abnormal behaviour when asked to place a banana and an orange in a single category: some patients categorize them at a concrete level (e.g., “both have peel”), while others continue to look for differences between these objects (e.g., “one is yellow, the other is orange”). These observations raise the question of whether abstraction and similarity detection are distinct processes involved in abstract categorization, and that depend on separate areas of the prefrontal cortex (PFC). We designed an original experimental paradigm for a functional magnetic resonance imaging (fMRI) study involving healthy subjects, confirming the existence of two distinct processes relying on different prefrontal areas, and thus explaining the behavioural dissociation in frontal lesion patients. We showed that: 1) Similarity detection involves the anterior ventrolateral PFC bilaterally with a right-left asymmetry: the right anterior ventrolateral PFC is only engaged in detecting physical similarities; 2) Abstraction per se activates the left dorsolateral PFC

Anomalies in the review process and interpretation of the evidence in the NICE guideline for chronic fatigue syndrome and myalgic encephalomyelitis

Chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME) is a disabling long-term condition of unknown cause. The National Institute for Health and Care Excellence (NICE) published a guideline in 2021 that highlighted the seriousness of the condition, but also recommended that graded exercise therapy (GET) should not be used and cognitive-behavioural therapy should only be used to manage symptoms and reduce distress, not to aid recovery. This U-turn in recommendations from the previous 2007 guideline is controversial.We suggest that the controversy stems from anomalies in both processing and interpretation of the evidence by the NICE committee. The committee: (1) created a new definition of CFS/ME, which 'downgraded' the certainty of trial evidence; (2) omitted data from standard trial end points used to assess efficacy; (3) discounted trial data when assessing treatment harm in favour of lower quality surveys and qualitative studies; (4) minimised the importance of fatigue as an outcome; (5) did not use accepted practices to synthesise trial evidence adequately using GRADE (Grading of Recommendations, Assessment, Development and Evaluations trial evidence); (6) interpreted GET as mandating fixed increments of change when trials defined it as collaborative, negotiated and symptom dependent; (7) deviated from NICE recommendations of rehabilitation for related conditions, such as chronic primary pain and (8) recommended an energy management approach in the absence of supportive research evidence.We conclude that the dissonance between this and the previous guideline was the result of deviating from usual scientific standards of the NICE process. The consequences of this are that patients may be denied helpful treatments and therefore risk persistent ill health and disability

Anomalies in the review process and interpretation of the evidence in the NICE guideline for chronic fatigue syndrome and myalgic encephalomyelitis

Chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME) is a disabling long-term condition of unknown cause. The National Institute for Health and Care Excellence (NICE) published a guideline in 2021 that highlighted the seriousness of the condition, but also recommended that graded exercise therapy (GET) should not be used and cognitive-behavioural therapy should only be used to manage symptoms and reduce distress, not to aid recovery. This U-turn in recommendations from the previous 2007 guideline is controversial.We suggest that the controversy stems from anomalies in both processing and interpretation of the evidence by the NICE committee. The committee: (1) created a new definition of CFS/ME, which 'downgraded' the certainty of trial evidence; (2) omitted data from standard trial end points used to assess efficacy; (3) discounted trial data when assessing treatment harm in favour of lower quality surveys and qualitative studies; (4) minimised the importance of fatigue as an outcome; (5) did not use accepted practices to synthesise trial evidence adequately using GRADE (Grading of Recommendations, Assessment, Development and Evaluations trial evidence); (6) interpreted GET as mandating fixed increments of change when trials defined it as collaborative, negotiated and symptom dependent; (7) deviated from NICE recommendations of rehabilitation for related conditions, such as chronic primary pain and (8) recommended an energy management approach in the absence of supportive research evidence.We conclude that the dissonance between this and the previous guideline was the result of deviating from usual scientific standards of the NICE process. The consequences of this are that patients may be denied helpful treatments and therefore risk persistent ill health and disability

Etude des bases neurales de la catégorisation chez les sujets sains et les patients cérébro-lésés

Categorization is a set of mental processes that allow classifying objects and events. It is crucial in various contexts such as survival in animals, concept learning in children, abstract reasoning and problem solving. Patients with brain lesions involving the prefrontal cortex are impaired in categorization tasks. Categorization impairment correlates with functional autonomy in dementia. In the first part, we have developed a task, named SimiCat that we designed in order to assess categorization abilities in patients. With the help of this task, we showed that differentiation errors are specific of frontal patients. The SimiCat task has a good diagnostic value to distinguish behavior variant Frontotemporal dementia from Alzheimer disease.In the second part, we assessed the brain correlates of categorization. With functional MRI, we showed that abstraction involves the left dorsolateral prefrontal cortex, while similarity detection involves bilateral ventrolateral prefrontal cortex. With voxel-based morphometry we showed that variability in categorization performances correlates with the volume of the right anterior temporal lobe, with a caudo-rostral gradient according to abstraction. In the third part, we developed a double priming task that we will use to assess automatic categorization processes in patients with temporal and frontal lesions. Based on these results, we propose a model of brain organization for categorization. This model involves both anterior temporal lobes, as well as bilateral ventrolateral and left dorsolateral prefrontal cortices. Our results also contribute to a better understanding and management of patients suffering from categorization deficits.La catégorisation est un ensemble d’opérations mentales qui permettent de classer les objets et les évènements. C’est un processus crucial pour de nombreuses situations, telles que la survie dans le monde animal, l’apprentissage chez l’enfant, ou encore le raisonnement abstrait et la résolution de problèmes. Les patients ayant des lésions du cortex préfrontal présentent des difficultés pour les tâches de catégorisation, et l’existence de ces difficultés est corrélée au handicap fonctionnel de ces patients. Dans une première partie, nous avons mis au point une tâche de catégorisation adaptée pour l’utilisation chez le patient, intitulée SimiCat. A l’aide de cette tâche, nous avons précisé les difficultés de catégorisation des patients et montré que les erreurs de type différenciations sont spécifiques des patients frontaux. La tâche SimiCat présente une très bonne valeur diagnostique pour distinguer les patients ayant une démence fronto-temporale de ceux ayant une maladie d’Alzheimer. Dans une deuxième partie, nous avons utilisé l’IRM fonctionnelle pour préciser les bases cérébrales de deux processus clés pour la catégorisation : l’abstraction et la détection de similitudes. Nous avons montré que l’abstraction repose sur le cortex préfrontal dorsolatéral gauche, alors que la détection de similitudes repose sur le cortex préfrontal ventrolatéral bilatéral. A l’aide de la morphométrie basée sur le voxel, nous avons montré que la variabilité des performances de catégorisation des sujets sains était corrélée au volume de la portion antérieure du gyrus temporal moyen et inférieur droit, avec un gradient postéro-antérieur selon le niveau d’abstraction de la catégorisation. Dans une troisième partie, nous avons mis au point une tâche de double amorçage sémantique que nous utiliserons pour étudier les processus de catégorisation automatique chez les patients ayant des lésions frontales et temporales. A partir de ces résultats, nous proposons un modèle d’organisation cérébrale pour la catégorisation, reposant sur les régions temporales antérieures, le cortex préfrontal ventrolatéral bilatéral et dorsolatéral gauche. Nos résultats permettent également de mieux comprendre les déficits de catégorisation des patients, ce qui permettra d’adapter leur prise en charge diagnostique et thérapeutique

Cerebral bases of categorization in healthy volunteers and brain-injured patients

La catégorisation est un ensemble d’opérations mentales qui permettent de classer les objets et les évènements. C’est un processus crucial pour de nombreuses situations, telles que la survie dans le monde animal, l’apprentissage chez l’enfant, ou encore le raisonnement abstrait et la résolution de problèmes. Les patients ayant des lésions du cortex préfrontal présentent des difficultés pour les tâches de catégorisation, et l’existence de ces difficultés est corrélée au handicap fonctionnel de ces patients. Dans une première partie, nous avons mis au point une tâche de catégorisation adaptée pour l’utilisation chez le patient, intitulée SimiCat. A l’aide de cette tâche, nous avons précisé les difficultés de catégorisation des patients et montré que les erreurs de type différenciations sont spécifiques des patients frontaux. La tâche SimiCat présente une très bonne valeur diagnostique pour distinguer les patients ayant une démence fronto-temporale de ceux ayant une maladie d’Alzheimer. Dans une deuxième partie, nous avons utilisé l’IRM fonctionnelle pour préciser les bases cérébrales de deux processus clés pour la catégorisation : l’abstraction et la détection de similitudes. Nous avons montré que l’abstraction repose sur le cortex préfrontal dorsolatéral gauche, alors que la détection de similitudes repose sur le cortex préfrontal ventrolatéral bilatéral. A l’aide de la morphométrie basée sur le voxel, nous avons montré que la variabilité des performances de catégorisation des sujets sains était corrélée au volume de la portion antérieure du gyrus temporal moyen et inférieur droit, avec un gradient postéro-antérieur selon le niveau d’abstraction de la catégorisation. Dans une troisième partie, nous avons mis au point une tâche de double amorçage sémantique que nous utiliserons pour étudier les processus de catégorisation automatique chez les patients ayant des lésions frontales et temporales. A partir de ces résultats, nous proposons un modèle d’organisation cérébrale pour la catégorisation, reposant sur les régions temporales antérieures, le cortex préfrontal ventrolatéral bilatéral et dorsolatéral gauche. Nos résultats permettent également de mieux comprendre les déficits de catégorisation des patients, ce qui permettra d’adapter leur prise en charge diagnostique et thérapeutique.Categorization is a set of mental processes that allow classifying objects and events. It is crucial in various contexts such as survival in animals, concept learning in children, abstract reasoning and problem solving. Patients with brain lesions involving the prefrontal cortex are impaired in categorization tasks. Categorization impairment correlates with functional autonomy in dementia. In the first part, we have developed a task, named SimiCat that we designed in order to assess categorization abilities in patients. With the help of this task, we showed that differentiation errors are specific of frontal patients. The SimiCat task has a good diagnostic value to distinguish behavior variant Frontotemporal dementia from Alzheimer disease.In the second part, we assessed the brain correlates of categorization. With functional MRI, we showed that abstraction involves the left dorsolateral prefrontal cortex, while similarity detection involves bilateral ventrolateral prefrontal cortex. With voxel-based morphometry we showed that variability in categorization performances correlates with the volume of the right anterior temporal lobe, with a caudo-rostral gradient according to abstraction. In the third part, we developed a double priming task that we will use to assess automatic categorization processes in patients with temporal and frontal lesions. Based on these results, we propose a model of brain organization for categorization. This model involves both anterior temporal lobes, as well as bilateral ventrolateral and left dorsolateral prefrontal cortices. Our results also contribute to a better understanding and management of patients suffering from categorization deficits

Caractéristiques des malformations artérioveineuses cérébrales révélées par des crises d'épilepsie

PARIS7-Xavier Bichat (751182101) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Invalidation of Parkinson's disease diagnosis after years of follow-up based on clinical, radiological and neurophysiological examination

International audienceIntroduction : Diagnosis of Parkinson's disease (PD) is mainly based on clinical features. Accurate neurological examination is required but dopamine transporter (DaT) single photon emission computed tomography (SPECT) could be perfomed to support the diagnosis in ambiguous cases. The aim of this work is to describe the characteristics of patients with a prolonged PD misdiagnosis.Methods : We collected data from 24 patients initially diagnosed with PD who had an atypical long-term evolution. We analyzed demographic and clinical characteristics and antiparkinsonian drugs medication. Brain MRI, DaT-SPECT and/or accelerometry/electromyography (EMG) recording were performed in a subgroup of patients. We analyzed the causes of erroneous PD diagnosis as well as the final diagnoses.Results : Mean age at PD diagnosis was 60.4 ± 14.8 years. Symptoms at onset were rest tremor (n = 19), gait instability (n = 7) and micrographia (n = 4). Mean duration before diagnosis correction was 8.4 ± 5.3 years. All patients were treated by antiparkinsonian drugs with a mean daily levodopa equivalent dose (LED) of 508.1 ± 528.4 mg. All 18 patients who underwent DaT-SPECT had a normal result. The most frequent final diagnoses were essential tremor (n = 11) and functional movement disorders (n = 9).Conclusion : Cases that have been initially diagnosed as PD and then progress in an atypical long-duration fashion may have been misdiagnosed. Absence of genuine bradykinesia, non-sustained response to antiparkinsonian drugs, or absence of levodopa-related side effects should prompt the clinician to reappraise the diagnosis and to consider performing a DaT-SPECT

Médias et journalisme

3e édition revue et complétée - Conférence permanente des directeurs·trices des unités de recherche en sciences de l’information et de la communication (CPDirSIC)International audienceLes recherches sur les médias et le journalisme abordent des questions à fort enjeu social et politique. Elles visent à rendre intelligible la fabrique desdiscours publics, médiatiques et politiques, dont ceux touchant, par exemple, à l’environnement, à la santé, à l’égalité et aux inégalités, aux usages desdata, aux violences, aux migrations. Qu’il soit question de la médiatisation du terrorisme ou du rôle des journalistes face à la terreur, des risques industriels, climatiques, sanitaires, de l’influence des discours sur les réseaux sociaux et, plus largement, de l’internet dans la construction des débats publics, sociaux et politiques, les recherches sur le journalisme et les médias permettent de comprendre les processus professionnels et communicationnels qui forgent les représentations communes, les repères sociaux et politiques qui configurent les événements, contribuent à la formation d’espaces publics pluriels et définissent des arènes dans lesquelles les acteurs de la démocratie ont à prendre position

A single-center series of 482 patients with functional motor disorders

International audienceFunctional motor disorders (FMD) are common and disabling. They are known to predominantly affect women and young to middle-aged patients, although they also occur during childhood or in the elderly. Demographic and clinical characteristics of patients with FMD are poorly known, since large series of consecutive patients are scarce.MethodsIn a chart review study, we retrospectively abstracted data from consecutive FMD patients who were referred to the Neurophysiology Department of the Salpêtrière University Hospital between 2008 and 2016 for treatment with repeated transcranial magnetic stimulation.Results482 patients were included. Most patients were women (73.7%). Median age at symptoms onset was 35.5 years and symptoms were mostly characterized by acute (47.3%) or subacute (46%) onset. Only 23% of patients were active workers, while 58.3% were unemployed because of FMD. Half of the patients had functional motor weakness (n = 241) whereas the other half had movement disorders (n = 241), mainly with tremor (21.1%) or dystonia (20.5%). Among all patients, 66.4% had psychiatric comorbidity and 82.6% reported a history of trauma in the 6 months before symptoms onset. No difference was found in age or gender according to clinical phenotypes.ConclusionThis large series will contribute to better characterize FMDs

Anterior Temporal Lobe Morphometry Predicts Categorization Ability

International audienceCategorization is the mental operation by which the brain classifies objects and events. It is classically assessed using semantic and non-semantic matching or sorting tasks. These tasks show a high variability in performance across healthy controls and the cerebral bases supporting this variability remain unknown. In this study we performed a voxel-based morphometry study to explore the relationships between semantic and shape categorization tasks and brain morphometric differences in 50 controls. We found significant correlation between categorization performance and the volume of the gray matter in the right anterior middle and inferior temporal gyri. Semantic categorization tasks were associated with more rostral temporal regions than shape categorization tasks. A significant relationship was also shown between white matter volume in the right temporal lobe and performance in the semantic tasks. Tractography revealed that this white matter region involved several projection and association fibers, including the arcuate fasciculus, inferior fronto-occipital fasciculus, uncinate fasciculus, and inferior longitudinal fasciculus. These results suggest that categorization abilities are supported by the anterior portion of the right temporal lobe and its interaction with other areas