ABSTRACT
The aim of this study was to investigate the hypothesis that the relative position of the stimuli within the lower and the upper visual fields influenccs the ocular scanning of a dynamic rcal-time scene. According to Previc, distinct brain systems code information coming from diffcrent spatial regions. In particular, Previc describes a Pcripersonal space and an ExtrapersonaI space, suggesting that they arc involved in vertical visual field asymmetry cffects. Here we verified that functional segregation of the space affects the ocular behavior, by testing the hypothesis that fixation scattering in the upper and the lower visual hemi-field reflects the functional asymmetry of neural processes. The NNI provided an index of the total scattering of the fixations as a function of the visual hemi-field. This suggest that when cognitive requirements are high, subjects adopt the strategy of a global exploration of the space; in contrast, in a low cognitive requirement situation, subjects adopt a more punctual strategy consisting of exploring larger portion of
space in the lower hemi-field than the ones in the uppcr hemi-field.
