Crise suicidaire et maladie d’Alzheimer débutante : intérêt d’une analyse neuropsychologique détaillée

RésuméIntroduction Le risque de développer une maladie d’Alzheimer augmente avec l’âge. Le rôle de celle-ci comme un facteur de risque indépendant de suicide n’est pas bien compris et demeure complexe et mal élucidé. L’objectif de cet article est d’envisager une compréhension neuropsychologique de la crise suicidaire dans le cas d’une maladie d’Alzheimer débutante. Méthode Une évaluation cognitive globale (Mini-Mental State Examination, Batterie Rapide d’Évaluation Frontale) complétée de l’exploration de l’inhibition cognitive selon ses fonctions d’accès (tâche de lecture en présence de distracteurs), de suppression (Trail Making Test), et de freinage (Stroop, Hayling, Go/No-Go) a été réalisée chez une femme souffrant d’une maladie d’Alzheimer (MMSE à 21/30) avant et après réalisation d’une tentative de suicide dans un contexte de dépression. Résultats L’échelle d’Hamilton était cotée à 24/52, l’échelle de dépression de Cornell à 21/38. L’intentionnalité suicidaire était modérée avec un score à 15/25 à l’échelle d’intentionnalité suicidaire de Beck. Initialement préservées, le déclin des fonctions exécutives a coïncidé avec l’émergence d’une crise suicidaire dans un contexte de dépression chez une patiente souffrant de maladie d’Alzheimer. Les fonctions de l’inhibition cognitive étaient altérées dans ses trois composantes, après ajustement des facteurs de confusion. Conclusion Une évaluation détaillée des fonctions exécutives et singulièrement de l’inhibition cognitive dans la population des patients atteints d’une maladie d’Alzheimer permettrait de détecter les personnes les plus à risque de passage à l’acte et de proposer une surveillance plus étroite dans le cadre des soins généraux de leur maladie. AbstractIntroduction The role of Alzheimer\u27s disease as a risk factor for suicide is unclear. The aim of this study was to understand neuropsychological component of the suicidal crisis in Alzheimer\u27s disease. Method Using an extensive neuropsychological battery, different aspects of cognitive inhibition were particularly examined: Access to relevant information (using the Reading with distraction task), suppression of no longer relevant information (Trail Making Test, Rule Shift Cards), and restraint of cognitive resources to relevant information (Stroop test, Hayling Sentence Completion test, Go/No-Go). One female Alzheimer depressed case was assessed before and after a suicide attempt. Results Ten days after the patient\u27s suicide attempt, dementia was still moderate with a MMSE score at 21/30 but with a worsening of executive functions (FAB at 8/18) in the context of depression and suicide. The Hamilton-Depression Rating Scale was at 24 (maximal score at 52), and the Cornell Scale for Depression was at 21 (maximal score at 38). Suicidal intent was moderate with a score of 9 on the Beck Suicide Intent Scale (maximal score at 25). The patient did not present a delirium, psychotic symptoms, or anosognosia. Her episodic memory was altered as shown by her semantic performance on verbal fluency (naming 12 animals in 120 seconds) and on lexical fluency (naming 8 words beginning with the letter P). Initially preserved, executive function declined during a suicidal crisis in a context of depression in Alzheimer\u27s disease case. Neuropsychological testing confirmed a dysexecutive syndrome (FAS at 8/18), with an impairment in her conceptualization capacity (MCST) and a deficit in cognitive inhibition and its access (reading task in the presence of distractors), deletion (TMT) and restraint (Stroop, Go/No-Go, Hayling) functions. Computed tomography has shown no signs of intracranial expansive process. Conclusion Assessing predictors of suicide and means of completion in patients with dementia may help the development of interventions to reduce risk of suicide among the growing population of individuals with dementia. Because of Alzheimer\u27s-related cognitive inhibition impairment, identification and intervention addressing the complex issues of depression, executive dysfunction and dementia may help clinicians to mitigate the risk of suicide in patients with Alzheimer\u27s disease

Spinal Cord Electrophysiology

The neonatal mouse spinal cord is a model for studying the development of neural circuitries and locomotor movement. We demonstrate the spinal cord dissection and preparation of recording bath artificial cerebrospinal fluid used for locomotor studies. Once dissected, the spinal cord ventral nerve roots can be attached to a recording electrode to record the electrophysiologic signals of the central pattern generating circuitry within the lumbar cord

Transidentités et changement de sexe : le point de vue du sociologue - le rôle du psychiatre

International audienceQu’entend-on par transidentités ? Pourquoi des personnes transidentitaires veulent ou ne veulent pas changer de sexe ? Quel est le rôle du psychiatre dans le changement de sexe de personnes transidentitaires ? C’est à ces questions, aux enjeux souvent complexes, qu’Arnaud Alessandrin, sociologue, et Thierry Gallarda, psychiatre, répondent dans cet entretien

Caracterización de suelos de subrasante mediante el uso del penetrómetro dinámico de cono (PDC): Characterization of subsoil soils by using of dynamic cone penetrometer (DCP)

In the development of road projects, as well as in different infrastructure works, the characterization of the materials is necessary to know their behavior. In the case of subgrade materials, their support capacity can be defined by the CBR index, which is an indicator of their resistance to shear and whose estimation is made by various field and laboratory methods. The objective of this research is the characterization of the ground as subgrade material from the CBR index obtained with the dynamic cone penetrometer (PDC) test for unpaved roads in the municipality of Ocaña. Four stages of work have been proposed: Field recognition, sampling, field and laboratory tests, and analysis of the results. The soils in the study areas have a significant content of fines with percentages between 7% and 70% that classify as sands and clays according to the unified SUCS system, with plasticity indexes between 6 and 25, and PDC index between 2 and 75 which corresponds to CBR values between 58% and 5% respectively, this applying the equation proposed by the INV standard E 172-13. In conclusion, the use of this method for the characterization of sub-grade soils is an alternative that provides economy and speed for the measurement of the support capacity through the CBR index. From the behavioral point of view, the PDC index allows sub-grading to be classified in a range from Poor to Excellent, which provides an initial perspective of the quality of the terrain.En el desarrollo de proyectos viales, así como en diferentes obras de infraestructura, es necesaria la caracterización de los materiales para conocer su comportamiento, en el caso de los materiales de sub-rasante, su capacidad de soporte se puede definir mediante el índice CBR, el cual es un indicador de su resistencia al cortante y cuya estimación se hace mediante diversos métodos de campo y laboratorio. El objetivo de esta investigación es la caracterización del suelo como material de sub-rasante a partir del índice CBR obtenido con el ensayo de penetrómetro dinámico de cono (PDC) para vías no pavimentadas del municipio de Ocaña. Se han planteado cuatro etapas de trabajo: Reconocimiento de campo, muestreo, ensayos de campo y laboratorio y análisis de los resultados. Los suelos en las zonas de estudio poseen un contenido significativo de finos con porcentajes entre 7% y 70% que clasifican como arenas y arcillas según el sistema unificado SUCS, con índices de plasticidad entre 6 y 25, e índice de PDC entre 2 y 75 que corresponde a valores de CBR entre 58% y 5% respectivamente, esto aplicando la ecuación que plantea la norma I.N.V. E 172-13. En conclusión, el uso de este método para la caracterización de suelos de sub-rasante es una alternativa que brinda economía y rapidez para la medición de la capacidad de soporte mediante el índice CBR. Desde el punto de vista del comportamiento el índice PDC permite clasificar la sub-rasantes en un rango de Pobre a Excelente, lo cual brinda una perspectiva inicial de la calidad del terreno

Caracterización de suelos de subrasante mediante el uso del penetrómetro dinámico de cono (PDC): Characterization of subsoil soils by using of dynamic cone penetrometer (DCP)

In the development of road projects, as well as in different infrastructure works, the characterization of the materials is necessary to know their behavior. In the case of subgrade materials, their support capacity can be defined by the CBR index, which is an indicator of their resistance to shear and whose estimation is made by various field and laboratory methods. The objective of this research is the characterization of the ground as subgrade material from the CBR index obtained with the dynamic cone penetrometer (PDC) test for unpaved roads in the municipality of Ocaña. Four stages of work have been proposed: Field recognition, sampling, field and laboratory tests, and analysis of the results. The soils in the study areas have a significant content of fines with percentages between 7% and 70% that classify as sands and clays according to the unified SUCS system, with plasticity indexes between 6 and 25, and PDC index between 2 and 75 which corresponds to CBR values between 58% and 5% respectively, this applying the equation proposed by the INV standard E 172-13. In conclusion, the use of this method for the characterization of sub-grade soils is an alternative that provides economy and speed for the measurement of the support capacity through the CBR index. From the behavioral point of view, the PDC index allows sub-grading to be classified in a range from Poor to Excellent, which provides an initial perspective of the quality of the terrain.En el desarrollo de proyectos viales, así como en diferentes obras de infraestructura, es necesaria la caracterización de los materiales para conocer su comportamiento, en el caso de los materiales de sub-rasante, su capacidad de soporte se puede definir mediante el índice CBR, el cual es un indicador de su resistencia al cortante y cuya estimación se hace mediante diversos métodos de campo y laboratorio. El objetivo de esta investigación es la caracterización del suelo como material de sub-rasante a partir del índice CBR obtenido con el ensayo de penetrómetro dinámico de cono (PDC) para vías no pavimentadas del municipio de Ocaña. Se han planteado cuatro etapas de trabajo: Reconocimiento de campo, muestreo, ensayos de campo y laboratorio y análisis de los resultados. Los suelos en las zonas de estudio poseen un contenido significativo de finos con porcentajes entre 7% y 70% que clasifican como arenas y arcillas según el sistema unificado SUCS, con índices de plasticidad entre 6 y 25, e índice de PDC entre 2 y 75 que corresponde a valores de CBR entre 58% y 5% respectivamente, esto aplicando la ecuación que plantea la norma I.N.V. E 172-13. En conclusión, el uso de este método para la caracterización de suelos de sub-rasante es una alternativa que brinda economía y rapidez para la medición de la capacidad de soporte mediante el índice CBR. Desde el punto de vista del comportamiento el índice PDC permite clasificar la sub-rasantes en un rango de Pobre a Excelente, lo cual brinda una perspectiva inicial de la calidad del terreno

Spinal Locomotor Circuits Develop Using Hierarchical Rules Based on Motorneuron Position and Identity

SummaryThe coordination of multi-muscle movements originates in the circuitry that regulates the firing patterns of spinal motorneurons. Sensory neurons rely on the musculotopic organization of motorneurons to establish orderly connections, prompting us to examine whether the intraspinal circuitry that coordinates motor activity likewise uses cell position as an internal wiring reference. We generated a motorneuron-specific GCaMP6f mouse line and employed two-photon imaging to monitor the activity of lumbar motorneurons. We show that the central pattern generator neural network coordinately drives rhythmic columnar-specific motorneuron bursts at distinct phases of the locomotor cycle. Using multiple genetic strategies to perturb the subtype identity and orderly position of motorneurons, we found that neurons retained their rhythmic activity—but cell position was decoupled from the normal phasing pattern underlying flexion and extension. These findings suggest a hierarchical basis of motor circuit formation that relies on increasingly stringent matching of neuronal identity and position

Npn-1 Contributes to Axon-Axon Interactions That Differentially Control Sensory and Motor Innervation of the Limb

The initiation, execution, and completion of complex locomotor behaviors are depending on precisely integrated neural circuitries consisting of motor pathways that activate muscles in the extremities and sensory afferents that deliver feedback to motoneurons. These projections form in tight temporal and spatial vicinities during development, yet the molecular mechanisms and cues coordinating these processes are not well understood. Using cell-type specific ablation of the axon guidance receptor Neuropilin-1 (Npn-1) in spinal motoneurons or in sensory neurons in the dorsal root ganglia (DRG), we have explored the contribution of this signaling pathway to correct innervation of the limb. We show that Npn-1 controls the fasciculation of both projections and mediates inter-axonal communication. Removal of Npn-1 from sensory neurons results in defasciculation of sensory axons and, surprisingly, also of motor axons. In addition, the tight coupling between these two heterotypic axonal populations is lifted with sensory fibers now leading the spinal nerve projection. These findings are corroborated by partial genetic elimination of sensory neurons, which causes defasciculation of motor projections to the limb. Deletion of Npn-1 from motoneurons leads to severe defasciculation of motor axons in the distal limb and dorsal-ventral pathfinding errors, while outgrowth and fasciculation of sensory trajectories into the limb remain unaffected. Genetic elimination of motoneurons, however, revealed that sensory axons need only minimal scaffolding by motor axons to establish their projections in the distal limb. Thus, motor and sensory axons are mutually dependent on each other for the generation of their trajectories and interact in part through Npn-1-mediated fasciculation before and within the plexus region of the limbs

Copying and Evolution of Neuronal Topology

We propose a mechanism for copying of neuronal networks that is of considerable interest for neuroscience for it suggests a neuronal basis for causal inference, function copying, and natural selection within the human brain. To date, no model of neuronal topology copying exists. We present three increasingly sophisticated mechanisms to demonstrate how topographic map formation coupled with Spike-Time Dependent Plasticity (STDP) can copy neuronal topology motifs. Fidelity is improved by error correction and activity-reverberation limitation. The high-fidelity topology-copying operator is used to evolve neuronal topologies. Possible roles for neuronal natural selection are discussed