Categoría: Papers con abstracts

Endophenotypes is one emerging strategy in schizophrenia research that is being used to identify the functional importance of genetically transmitted, brain-based deficits present in this disease. Currently, event-related potentials (ERPs) are timely used in this search. Several ERPs, including N400, present deficits in relation to schizophrenia. In order to assess the genetic liability of N400 as a possible endophenotype, a picture semantic matching task (congruent and incongruent pairs of pictures) was performed by 21 unaffected first-degree relatives of patients with schizophrenia, 21 DSM-IV diagnosed schizophrenia probands, and 21 control subjects, matched by age, gender and educational level. Probands and relatives were selected form Multiplex schizophrenia families. Significantly reduced N400 amplitude for congruent categories in N400 was found in probands and relatives in relation to controls. The latency onset and the maximum peak latency of N400 were delayed in both, relatives and probands groups compared to control. The voltage maps of incongruous-minus-congruous difference indicate a more reduced right restricted negativity in probands and relatives, when compared to a widely extended bilateral negativity in controls. No general differences were found between patients and relatives. These results demonstrate an electrophysiological deficit in semantic match processing in clinically unaffected first-degree relatives of patients with schizophrenia, suggesting a possible use of this marker as endophenotype.

Evaluating brain function in patients with disorders of consciousness may offer important clues to their state of awareness and help to predict prognosis. Disorders of consciousness mainly comprise the comatose state, the vegetative state, and the minimally conscious state. These disorders typically stem from acute brain insults caused by hypoxic-ischemic neural injury or traumatic brain injury, and the type of brain injury frequently determines the neuropathology. Current knowledge, including results from our laboratory, supports a model of extended brain tissue damage from the midbrain to the cortex in anoxia patients and a model of focal or multifocal cortical lesions in trauma patients. These differing models may help to explain differences in prognosis and outcomes in these excruciating life situations. Although the neural basis of consciousness remains puzzling, findings from normal volunteers and pathologies of consciousness show that widely distributed networks such as thalamofrontal and parietofrontal systems may be critical.

In recent years, studies have suggested that gestures influence comprehension of linguistic expressions, for example, eliciting an N400 component in response to a speech/gesture mismatch. In this paper, we investigate the role of gestural information in the understanding of metaphors. Event related potentials (ERPs) were recorded while participants viewed video clips of an actor uttering metaphorical expressions and producing bodily gestures that were congruent or incongruent with the metaphorical meaning of such expressions. This modality of stimuli presentation allows a more ecological approach to meaning integration. When ERPs were calculated using gesture stroke as time-lock event, gesture incongruity with metaphorical expression modulated the amplitude of the N400 and of the late positive complex (LPC). This suggests that gestural and speech information are combined online to make sense of the interlocutor’s linguistic production in an early stage of metaphor comprehension. Our data favor the idea that meaning construction is globally integrative and highly context-sensitive.

Human learning and memory evaluation in real-life situations remains difficult due to uncontrolled variables. Buenos Aires waiters, who memorize all the orders without written support, were evaluated in situ. Waiters received either eight different orders and customers remained seated in their original locations (OL), or changed locations (CL). Match between orders, subjects and location was decreased only in CL. Waiters’ feature/location strategy links client with position at the table and beverage later. The hypothesis we raise is that memory-schemas link working memory to long-term memory networks through rapid encoding, making the information resistant to interference and enabling its fast retrieval if necessary cues are present.

Interpretación de refranes en la Enfermedad de Alzheimer. Autores Báez S, Montañes P.  Año 2009 Journal  Báez S, Montañes P.  Volumen 49(11): 566-72 Abstract   Otra información    

In the last few decades, several works on event related potentials (ERPs hereafter) during sleep have been reported. In spite of numerous studies, clear methodological rules for this kind of study are often missing, making it difficult to valorize the scope of these results. We propose here a description of methodological aspects to be considered when evaluating ERPs during sleep. The use of Rechtschaffen and Kales rules versus automatic methods is assessed, plus the additional use of certain quantitative measures. Additionally, two topics are discussed which must be controlled in ERPs sleep studies: the First Night Effect, and sleep disturbances. Better control of experimental paradigms is relevant for the growth of the neuroscience of sleep.

A 37-year-old woman with celiac disease, recurrent psychosis, and Parkinsonism. Autores González-Alemán G, Florenzano N, Padilla E, Bourdieu M, Guerrero G, Calvó M, Strejilevich S, de Erausquin GA.  Año 2006 Journal  González-Alemán G, Florenzano N, Padilla E, Bourdieu M, Guerrero G, Calvó M, Strejilevich S, de Erausquin GA.  Volumen 21(5): 729-731 Abstract   Otra información    

Temperament traits associated with risk of schizophrenia in an indigenous population of Argentina. Autores Calvó M, Padilla E, González-Alemán G, Bourdieu M, Guerrero G, Strejilevich S, Escobar J, Svrakic N, Cloninger CR, de Erausquin GA.  Año 2006 Journal  Calvó M, Padilla E, González-Alemán G, Bourdieu M, Guerrero G, Strejilevich S, Escobar J, Svrakic N, Cloninger CR, de Erausquin GA.  Volumen 83(2-3): 299-302 Abstract   Otra información    

Objetivos: La escasez de datos y de camas para internación psiquiátrica en hospitales generales hace prioritaria la producción de información sobre el funcionamiento de este tipo de servicios. El objetivo de este trabajo consiste en describir la población de pacientes internados en una sala de Psiquiatría de un hospital general de la ciudad de Buenos Aires. Método: Entre el 1º de juno del 2004 y el 31 de mayo de 2005 se llevó a cabo un estudio de corte naturalístico, prospectivo y descriptivo, recabando los datos de los pacientes que ingresaron en la sala de Internación del Servicio de Psiquiatría del Hospital «Teodoro Alvarez «. Resultados: La edad promedio fue de 36.7 años; los motivos de ingreso estuvieron relacionados en su mayoría con cuadros de descompensación psicótica y de riesgo para sí. Se produjeron 82 internaciones (correspondientes a 71 pacientes) con 68 egresos en el mismo período. El 48.8% presentaba antecedentes de internaciones previas (de los cuales el 25.6% presentaban cuatro o más internaciones). El 29.3% ingresó por vía judicial. Se retiraron sin alta médica el 19.1%. Los diagnósticos de egreso más frecuentes fueron: Esquizofrenia (29.4%), Trastorno por abuso de sustancia (22.1%), Trastorno límite de la personalidad (10.3%), Trastorno bipolar (8.8%) y Trastorno depresivo (7.4%). El tiempo promedio de internación fue de 45.4 días (pero con un giro cama de 4.1) de las cuales aproximadamente el 90% duraron menos de 90 días. Conclusiones: Estos datos pueden ser comparados con los ya producidos por otros Servicios de Psiquiatría similares y permiten avanzar en mejorar el funcionamiento de servicios que progresivamente tendrán que ser priorizados por sobre los tradicionales manicomios.

Structural brain imaging and neuropsychological data implicate the orbital aspects of prefrontal cortex in the developing neuropathology of fvFTD. Damage to this region is associated with deficient performance on laboratory tasks assessing theory of mind (ToM) and affective decision-making (DM), but the relationship between these two capacities in patients with prefrontal cortex dysfunction is unclear. We studied a group of patients with early/mild fvFTD (n=20) and a group of matched normal controls (n=10) on the Iowa gambling task (IGT) of affective decision-making, and the «reading the mind in the eyes » (MIE) and «faux pas » (FP) tests of ToM. The fvFTD group was impaired in both ToM tasks and the IGT. While performance measures from the two ToM tasks were significantly correlated, they were not associated with IGT performance. This suggests that whilst similar prefrontal circuitry is implicated in ToM and DM tasks, these cognitive domains may be independent. In clinical settings, the IGT may be useful as a complementary tool to the frontal test battery for patients with early/mild fvFTD. Deficits in decision-making and ToM observed in this study have distinct but additive effects upon the development of social behaviour in patients with prefrontal dysfunction.