Visual differentiation of complex stimuli: emotional expressions of a human face
Ch.A. Izmailov, S.G. Korshunova, M.S. Shekhter, A.Ya. Potapova
Lomonosov Moscow State University, Psychological Institute of RAE, Moscow
In work results of dissimilarity judgments between complex stimuli – schematically represented faces – are considered. The given stimuli are characterized in distinctions of configuration as well as categorical distinctions connected with emotional expressions of the face. The spherical model of emotional expressions of schematic faces is constructed based on multidimensional scaling of dissimilarity estimates and evoked potentials of differentiations (EPD) between abrupt changes of stimuli in occipital and posterior temporal areas of the cerebral cortex. Two frames of references: spherical and Cartesian are interpreted as two types of neuronal multi-channels network. First one detects emotional expressions and second one – recognizes pattern variables. The continuation and hemispheric asymmetry of two recognition processing is discussed based on the cortical topography of spherical models constructed for different components of evoked potential of differentiation recorded from occipital and temporal sites.
It is shown, that activity of occipital and temporal areas of a cortex of the right hemisphere is connected with the contribution of an emotional component of the human face whereas the contribution of configuration characteristics is presented to both in temporal and occipital areas of the left hemisphere. In all sites, the information on emotional and configuration characteristics of the face is presented in interpeaks amplitude P120-N180 of EPD.
Keywords: spherical model of stimuli differentiations, evoked potentials of differentiations, multidimensional scaling, facial expressions, patterns recognition.