RESUMO
The aim of the present work was to readdress the problem of altered spatial localization in strabismic subjects and to assess whether and how spatial representation is affected by the degree of plasticity of the brain. We therefore compared targeting performance in adult subjects affected by acquired strabismus versus children affected by congenital strabismus. Our data confirm the correlation between deviation of the eye and targeting errors, but they also show that this correlation is not present when strabismus occurs early in life. We suggest that the neuronal machinery involved in the building of an internal representation of space reaches its full maturity several years after birth and that this might explain the limited differences observed in targeting errors between normal and strabismic children.
Assuntos
Percepção Espacial/fisiologia , Estrabismo/psicologia , Adulto , Envelhecimento/psicologia , Criança , Esotropia/psicologia , Feminino , Lateralidade Funcional/fisiologia , Humanos , Masculino , Plasticidade Neuronal/fisiologia , Desempenho Psicomotor/fisiologia , Estrabismo/congênito , Estrabismo/etiologiaRESUMO
The existence of an internal representation of visual space can be demonstrated by observing the ability to reconstruct different spatial locations in absence of visual object still indicating those positions. The characteristics of this spatial map were investigated in healthy human subjects instructed to point to different spatial positions previously indicated by a visual objects which disappeared. Pointings were made with different delays from the disappearance of the peripheral visual target and with different permanence time of it. The idea emerging from this study of the internal representation of visual space is that it is distorted, with the lower hemifield overestimated with respect to the upper one. Moreover, this map slowly deteriorates with time and its precision depends on the time during which the object can be observed.