A experiência sensório-motora influencia a representação semântico-lexical do corpo? Evidências de crianças típicas e com hemiplegia congênita

Abstract

Evidence from several lines of research indicates that human body knowledge is widely distributed in the adult brain. As the central nervous system employs different sensory channels, the mechanisms for body representation are different. Neuropsychological and neuroimage studies support this idea, showing the existence of three kinds of body representation in adults: body schema, body structural description and body image. The existence of these distinct levels of representation is suppoted by selective patterns of dissociation in neurological patients. There are two kinds of theories to explain the body representations source. The bottom-up theories presupposes that the body representations stem from the sensory-motor activities, by patterns of activities raised and stored at the brain. The alternative theory, top-down, presupposes the existence of a genetic blueprint for the body representations, that could be, at least, partially, inate. There are evidences for both models. This dissertation investigates, in an exploratory manner, the bottom-up and top-down influeces throughout the development of semantic body knowledge in typical children and children with hemiplegic cerebral palsy. The graph theory was applied in studies 1 and 2 to investigate the development of lexical-semantic knowledge in childhood. The first study was conducted with a sample of 204 typically developing children aged 4- to 12-years old and aimed to investigate the influence of childhood experiences on the lexical-semantic knowledge of animals, foods and body parts. This analysis allowed the exploration of the motor-sensory (body schema) among the lexical-semantic knowledge about the body parts (body image), using other lexical categories as controls (animals and foods). It was observed that the sensory-motor experiences influence the lexical-semantic knowledge about the body parts; showing that the categorical organization was compatible with the bottom-up model. However, there wasnt a specific pattern for the other semantic categories investigated, not observing a relation between the development and the controls categories was detected. After, the development of the body image in children with hemiplegic cerebral palsy was investigated, using the same techniques. This second study included a sample of 229 children (204 typically developing children, ranging from 4- to 12-years old; and 26 children with hemiplegic cerebral palsy, ranging from 7- to 15- years old). The hypothesis that an injury to the immature brain can generate deficits in the lexical-semantic knowledge about the body parts in children with congenital hemiplegia was investigated. After data analysis, was verified that cerebral palsy children present a delay in the body parts knowledge compared to controls with the same age, having body parts knowledge equivalent to that of the early stages of typical development. Overall, by examining the performance ate the tasks and analyzing the results patterns, it is concluded that there is an interaction between the representational modules, where deficits in sensorimotor schemas influence the lexical-semantic representations, resulting in losses on this type of body parts knowledge.Therefore, the results are compatible with an interactive model, according to which influences top-down interact with the sensory-motor experience (bottom-up influences). Despite the studies are exploratory, the findings support the hypothesis that there is an interaction between the levels of body knowledge over child development.