A assimetria funcional inter-hemisférica

• Ano de defesa: 1984
• Autor(a) principal: Gonçalves, Marcia Garcia
• Orientador(a): Penna, Antônio Gomes
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Link de acesso: http://hdl.handle.net/10438/9639

This study analyses the various aspects of functional inter-hemisferic assimetry, through a critical review of the litterature concerning clinical and experimental work, with normal individuals and neurological patients, which was considered most significant for the present configuration of this field of knowledge. The initial work reviewed concerns neurological patients with unilateral lesions, which provided the first evidence about an assymetrical organization of the cerebral hemispheres. Taking into account that inter-hemispheric assimetry is connected mainly with cognitive processes, the review analysed the more significant studies on aphasia, apraxia, agnosis and amnesia, all of which are directly related with cerebral assirnetry. Following this review, studies which utilized Wada's technique and in comissurotomized patients were analysed, with emphasis on a demonstration of their heavy influence over present knowledge of functional inter-hemispheric assimetry, either regarding the functional characterization of each cerebral hemisphere, or regarding a focusing of interest over this area of neuropsychological research. It is worth remarking that studies on the functional characterization of cerebral hemispheres were ultimately responsible fot the substitution of the concept of cerebral dominance by that of functional inter-hemispheric assimetry. As far as the review of studies done on normal individuals, the emphasis was placed on the progression from a focus on hemispherical characterization to one centered on the analysis of cognitive requirements neeessary for a given task; the purpose of this approach was to evaluate the participation proportion of the cerebral hemispheres in the execution of complex tasks. Individual differences regarding the standards of functional lateralization were evaluated with particular regard to those studies which utilized easily observable behavioral variables, such as manipulatory preferences and their family history, ocular preferences and the subject's sexo Emphasis was placed on correlational studies between the first mentioned variable and language lateralization, which have obtained a greater empirical support. The main models being presently evaluated in the litterature with regard to the dynamics or joint cerebral hemisphere activity were analysed nex. Though not completely satisfactory, Diamond and Beaumont's (Beaumont, 1974) was considered to be the most consistent through its proposal of a more integrated action between the cerebral hemispheres. Phylogenetic and ontogenetic analysis, as well as the analysis of the significance of the various cognitive processes required for complex tasks were also evaluated, as they are becoming one of the main centers of interest in the litterature concerning functional inter¬ hemispheric assimetry.