RESUMO
Chronic unpredictable mild stress (CUMS) is a widely used model to study stress-coping strategies in rodents. Different factors have been shown to influence whether animals adopt passive or active coping responses to CUMS. Individual adaptation and susceptibility to the environment seem to play a critical role in this process. To further investigate this relationship, we examined the effects of CUMS on Carioca high- and low-conditioned freezing rats (CHF and CLF, respectively), bidirectional lines of animals selected for high and low freezing in response to contextual cues that were previously associated with footshocks. For this purpose, the behavior of CHF and CLF animals was evaluated in the contextual fear conditioning, open field, elevated T maze, and forced swimming tests before and after 21 days of CUMS. For all tests, CHF rats were more susceptible to the effects of CUMS compared to CLF. CHF animals exposed to CUMS displayed a reduction in freezing behavior, decreased number of entries and time spent in the center of the open field, greater latencies to become immobile, and increased avoidance and escaping behaviors in the elevated T maze. Overall, these findings support the hypothesis that a heightened susceptibility to the environment exerts a strong influence on coping responses to chronic stress.
Assuntos
Medo , Estresse Psicológico , Adaptação Psicológica , Animais , Comportamento Animal , Depressão , Modelos Animais de Doenças , Reação de Congelamento Cataléptica , RatosRESUMO
Social cognition-the basis of all communicative and otherwise interpersonal relationships-is embedded in specific contextual circumstances which shape intrinsic meanings. This domain is compromised in the autism spectrum disorders (ASDs), including Asperger's syndrome (AS) (DSM-V). However, the few available reports of social cognition skills in adults with AS have largely neglected the effects of contextual factors. Moreover, previous studies on this population have also failed to simultaneously (a) assess multiple social cognition domains, (b) examine executive functions, (c) follow strict sample selection criteria, and (d) acknowledge the cognitive heterogeneity typical of the disorder. The study presently reviewed (Baez et al., 2012), addressed all these aspects in order to establish the basis of social cognition deficits in adult AS patients. Specifically, we assessed the performance of AS adults in multiple social cognition tasks with different context-processing requirements. The results suggest that social cognition deficits in AS imply a reduced ability to implicitly encode and integrate contextual cues needed to access social meaning. Nevertheless, the patients' performance was normal when explicit social information was presented or when the situation could be navigated with abstract rules. Here, we review the results of our study and other relevant data, and discuss their implications for the diagnosis and treatment of AS and other neuropsychiatric conditions (e.g., schizophrenia, bipolar disorder, frontotemporal dementia). Finally, we analyze previous results in the light of a current neurocognitive model of social-context processing.
RESUMO
A functional class refers to a circumstance in which responding is controlled by features of stimuli that are common to all the class members. It is argued that an analysis of substitution of stimulus functions is needed to account for the acquisition of functional classes of different varieties. We examined the acquisition of classes of comparison stimuli presented in a standard matching to sample (MTS) preparation by exposing participants to three tests in which a contextual cue provided the basis for the formation of these classes. In this preparation the equivalence training and test phases served as a masking task that prevented the interference of naming processes or the development of rules describing the commonalities among target class members (comparison stimuli). Most of the participants showed responding with respect to one or more comparison classes even in the absence of specific operant training. Findings suggest that the function shared by a given set of stimuli may be acquired by another stimulus in the absence of operant reinforcement and without the involvement of verbal rules.
Se habla de adquisición de clases funcionales cuando el comportamiento es controlado por aquellas propiedades de los estímulos que son comunes a todos los miembros de la clase. Un análisis en términos de sustitución de funciones es necesario para explicar la adquisición de varios tipos de clases funcionales. En este estudio se examinó la adquisición de clases de estímulos comparadores en un entrenamiento estándar de igualación a la muestra, mediante la inclusión de un estímulo contextual diferente para cada clase de comparadores. Las fases de entrenamiento y pruebas de equivalencia sirvieron como una tarea de enmascaramiento para prevenir la interferencia de respuestas verbales con respecto a las relaciones entre el estímulo contextual y los comparadores durante el entrenamiento. Hubo respuestas respecto a una o más clases de comparadores para la mayoría de los participantes. Los hallazgos indican que la función compartida por los miembros de una clase puede ser adquirida por un estímulo arbitrario en ausencia de refuerzo y de respuestas verbales.