Categoría: Papers con abstracts

Brain processes and social processes are not as separated as many of our Social Psychology and Neuroscience departments. This paper discusses the potential contribution of social neuroscience to the development of a multi-level, dynamic, and context-sensitive approach to prejudice. Specifically, the authors review research on event related potentials during social bias, stereotypes, and social attitudes measurements, showing that electrophysiological methods are powerful tools for analyzing the temporal fine-dynamics of psychological processes involved in implicit and explicit prejudice. Meta-theoretical implications are drawn regarding the social psychological modeling of social attitudes, and for the integration of social neuroscience into a multi-level account of cultural behavior.

Determining conscious processing in unresponsive patients relies on subjective behavioural assessment. Using data from hand electromyography, the authors studied the occurrence of subthreshold muscle activity in response to verbal command, as an objective indicator of awareness in 10 disorders of consciousness patients. One out of eight vegetative state patients and both minimally conscious patients (n = 2) demonstrated an increased electromyography signal specifically linked to command. These findings suggest electromyography could be used to assess awareness objectively in pathologies of consciousness.

En la actualidad los recursos tecnológicos constituyen herramientas cotidianas, sobre todo en el mundo de los niños y adolescentes. La psicoterapia ha tendido a dejar de lado el uso de los mismos. Según un consenso de expertos la evolución posible de la psicoterapia apuntaría a la incorporación de dichos recursos. Datos preliminares en una encuesta realizada a psicólogos de la Ciudad Autónoma de Buenos Aires y Conurbano bonaerense arrojan que, a pesar de que un alto porcentaje considera que los recursos tecnológicos pueden ser úiles para el desarrollo de la alianza y la optimización de las técnicas, al mismo tiempo manifiestan tener poco conocimiento acerca de los mismos y utilizarlos con poca frecuencia. El propósito de este artículo es revisar creencias y actitudes de los terapeutas respecto a la incorporación de dichas herramientas a la práctica clínica.

Disorders of consciousness have captivated neurologists, neuroscientists, and philosophers for decades, but few consistent studies have been conducted on these conditions due to their difficult experimental approach. In recent years, an increasing number of cognitive neuroscience research groups have examined the physiology of consciousness from an experimental perspective, despite the methodological and epistemological complexities of the field. While describing consciousness can be challenging, a close definition must acknowledge a combination of wakefulness and awareness. Form a neurobiological standpoint, it has been argued that the ascending reticular system and its thalamic projections are critical in modulating awareness and wakefulness sleep cycles. Awareness may be a function of the neural networks within the cortex, the thalamus, and the cortico-cortical system. Different models have been employed to tackle this difficult problem, including non-invasive in vivo studies, examination of conscious patients with brain lesions, and studies on both animals and patients with disorders of consciousness. This article reviews the scientific evidence for the neural basis of conscious and unconscious processes in different states of consciousness, focusing on patients in the vegetative and minimally conscious state.

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.