Functional brain organization of global and local visual perception: Analysis of event-related potentials |
| |
Authors: | R I Machinskaya E V Krupskaya A V Kurgansky |
| |
Institution: | 1.Institute of Developmental Physiology,Russian Academy of Education,Moscow,Russia |
| |
Abstract: | Event-related potentials (ERP) of the brain and psychometric indices (reaction time and percentage of correct responses) were
studied in adult subjects during recognizing hierarchical visual stimuli (letters), while the subject’s attention was drawn
to either the global or the local level of the stimulus. The psychophysical indices demonstrated the global precedence effect,
i.e., an increased recognition time of a small letter, which was a part of an incongruent stimulus. The ERP component analysis
demonstrated that differences in the regulatory mechanisms of attention and timing and topography of brain organization during
processing of visual information depended on the level of recognizing the hierarchical stimulus (global vs. local). Visual
recognition at the local level was accompanied by a stronger activation of visual associative areas (P
z
and T
6) at the stage of sensory feature analysis (P1 ERP component), as well as by the predominant involvement of the temporal inferior cortex of the right hemisphere (T
6) at the stage of sensory categorization (the P2 ERP component) and of the frontal cortex of the right hemisphere at the stage of selection for the relevant target features
(the N2 ERP component). Visual recognition at the global level was accompanied by significant involvement of the early sensory selection
(the N1 ERP component) and predominant activation of the parietal cortex of the right hemisphere (P
4) at the stage of sensory categorization (the P2 ERP component), as well as at the stage of identification of the target stimulus (the P3 ERP component). Perception of a stimulus at the global level is assumed to depend mostly on the analysis of its spatial
features in the dorsal visual system, whereas perception at the local level involves analysis of the object-related features
in the ventral visual system. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|