Конфигуративные и категориальные характеристики зрительного восприятия Ч. А. Измайлов МГУ им. М. В. Ломоносова, Москва

. From a geometrical point of view the angle is a combination of two lines. It is in accordance with intuitive experience that angles are more complex perceptual stimuli than lines, and perception of angles is accomplished at a higher level of information processing than perception of lines. This claim is supported by both neurophysiologic (Hubel & Wiesel, 1962, Shevelev et al., 2000) and psychophysical (Granovskaya, Bereznaya & Grigoreva, 1981; Selfridge & Neisser, 1974) arguments. However, another data (Sillito & Versiani, 1977; Supin, 1981) permit to suggest an alternative idea, namely that lines and angles are equally specific percepts, and discrimination of angles is neither more complex nor simpler than discrimination of lines. Some computer programs which recognize three-dimensional objects represented by contour drawings (Guzman, 1968; Waltz, 1975) have been based on a set of 8-10 key stimuli. The keys were combinations of two, three, four or five lines. This set of basic combinations can be considered as an alphabet of contour scenes. It may be assumed that the basic combinations of lines are perceptually equivalent, independently from geometrical complexity of stimuli.

In first experiment 10 lines of different orientations (from 0° up to 162° in relation to visual horizontal axis) were used as a 45 pair combination of lines. Psychophysical part of research consists from four sets of experiments.

Example of stimuli – angles In the next experiment 30 stimuli (12 angles from 23° up to 165° having different orientations in a frontal plane) were presented on a TV monitor.

In the third experiment 24 angles were presented as fingers on schematic watch dial, and in the forth experiment 10 lines were presented as a small finger on a schematic watch dial. One named these stimuli as line segments because one of the ends of line-finger was fixed.

9. гнев, ненависть радость восторг 6 горе. 5. спокойствие 4 удовольствие удивление 1 удивление удовольствие Схематические лица, использованные в качестве стимулов. Они выбраны так, чтобы в них были представлены основные крнфигуратичные и экспрессивные характеристики лица 3. печаль горе

Fig Example of visual evoked potential recorded from the occipital area of the humans brain as response on abrupt changes color stimuli. N1(N87), N1(N87) – P1(P120) - color components of VEPD P1(P120) – N2(N180), N2(N180), N2(N180) – P2(P230) – pattern components of VEPD

Fig Matrix of evoked potentials of differences (DEP), recorded in response to abrupt stimulus (line orientations) change. Rows and columns of matrix represent the same set of stimuli while the entries contain all pair-wise dissimilarities from the cortical point of view. Amplitudes of the component increasing monotonically with increasing of differences between stimuli can be used as measures of dissimilarity.

Spherical model of line orientations obtained by multidimensional scaling of dissimilarities estimates. Two dimensions of Euclidean plane represent dual-channel neuronal network detecting stimuli orientations on the frontal plane of visual space. First axis corresponds horizontal-vertical opponent channel, and second one – left-right declination channel.

Spherical model of line- segments obtained by multidimensional scaling of dissimilarity estimates. Two dimensions of Euclidean plane represent dual-channel neuronal network detecting stimuli orientations on the frontal plane of visual space. First axis corresponds horizontal-vertical opponent channel, and second one – left-right declination channel.

b) Psychophysical function of line-segments orientation obtained from spherical model. Abscissa axis represents orientation of small fingers oh schematic watch dials, and axis of ordinate represents perceived orientations measured as angles of points on the plane X1X2..

Location of points-stimuli (angles) in two-dimensional space. The configuration of points can be presented by semicircle on a plane.

Psychophysical function of perceived angle values obtained from spherical model. Abscissa axis represents angles of stimuli, and axis of ordinate represents perceived angles measured as spherical coordinate of point on the X1X2 plane.

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Projections of point-stimuli on X1X2 plane of two-dimensional space obtained by multidimensional scaling of interpeaks amplitudes of N180- P230, recorded on a stimuli- lines differences. Two dimensions of Euclidean plane represent dual-channel neuronal network detecting stimuli orientations on the frontal plane of visual space. The circle and the direct lines represent spherical and city- block models of points configurations. The both models correspond to points configurations. Occipital sites O1 and O2

Projections of point-stimuli on X1X2 plane of two-dimensional space obtained by multidimensional scaling of interpeaks amplitudes of N180- P240, recorded on a stimuli-lines differences. Two dimensions of Euclidean plane represent dual-channel neuronal network detecting stimuli orientations on the frontal plane of visual space. The circle and the direst lines represent spherical and city- block models of points configurations. Temporal sites T5 and T6

Projections of point-stimuli on X1X2 plane of two-dimensional space obtained by multidimensional scaling of early interpeaks amplitudes of P120- N180, recorded on a stimuli-lines differences. Only first dimension of Euclidean plane (X1) represents a monotonic correspondence with stimuli orientations on the frontal plane of visual space. The second one reflects a noise of neuronal environment. Occipital sites O1 and O2

Projections of point-stimuli on X1X2 plane of two- dimensional space obtained by multidimensional scaling of interpeaks amplitudes of P120-N180, recorded on a stimuli-lines differences. Only first dimension of Euclidean plane (X1) represents a monotonic correspondence with stimuli orientations on the frontal plane of visual space. The second one reflects a noise of neuronal environment. Temporal sites T5 and T6

In the third experiment 24 angles were presented as fingers on schematic watch dial, and in the forth experiment 10 lines were presented as a small finger on a schematic watch dial. One named these stimuli as line segments because one of the ends of line-finger was fixed.

Circular representation of stimuli in subjective space Dimension Schematic watch dials Line orientation Line segment Angles Coefficient of correlation ,97 0,98 Stress ,060,030,080,06 Mean radius1,791,932,01,0 Standard deviation 0,160,11 0,040,05 Coefficient of variation % ,35,28,19,0

Projections of point-stimuli on X1X2 plane of three- dimensional space obtained by multidimensional scaling of dissimilarities estimates. The stimuli were angles between fingers on schematic diagrams of watch dials. Two dimensions of Euclidean plane represent dual-channel neuronal network detecting stimuli orientations on the frontal plane of visual space. First axis corresponds horizontal-vertical opponent channel, and second one – left-right declination channel.

Psychophysical function of perceived orientations of angles obtained from spherical model of schematic watch dials. Abscissa axis represents orientation of bisectors of stimuli, and axis of ordinate represents perceived orientations of angles between fingers measured as spherical coordinates of points on the X1X2 plane of three- dimensional space

Projections of point-stimuli on X1X3 plane of three- dimensional space obtained by multidimensional scaling of dissimilarities estimates. The stimuli were angles between fingers on schematic diagrams of watch dials. Two dimensions of Euclidean plane represent dual-channel neuronal network detecting values of stimuli-angles on the frontal plane of visual space. First axis corresponds horizontal-vertical opponent channel, and second one is a projection of.twodimensional space of angle discrimination

Three stage neuronal net of color vision Light stimulus

1 удивление удовольствие 4 удовольствие удивление 5. спокойствие 6 горе. 7. радость восторг гнев, ненависть. Схематические лица, использованные в качестве стимулов. Они выбраны так, чтобы в них были представлены основные крнфигуратичные и экспрессивные характеристики лица 3. печаль горе

Проекции 9 точек- схематических лиц на горизонтальную плоскость (Х1Х2) четырехмерного пространства, полученного многомерным шкалированием оценок воспринимаемых различий. Номера точек соответствуют номерам лиц на предыдущкм слайде. Эмоциональные характеристики некоторых лиц даны в виде названий соответствующих эмоций. Окружность вокруг каждой точки характеризует область случайной ошибки.

Проекции 9 точек-схематических лиц на вертикальную плоскость (Х1Х3) четырехмерного пространства, полученного многомерным шкалированием оценок воспринимаемых различий. Номера точек соответствуют номерам лиц на предыдущкм слайде. Эмоциональные характеристики некоторых лиц даны в виде названий соответствующих эмоций.

Проекции 9 точек- схематических лиц на плоскость (Х3Х4) четырехмерного пространства, полученного многомерным шкалированием оценок воспринимаемых различий. Номера точек соответствуют номерам лиц на предыдущкм слайде. Окружность вокруг каждой точки характеризует область случайной ошибки.

Fig Example of visual evoked potential recorded from the occipital area of the humans brain as response on abrupt changes color stimuli. N1(N87), N1(N87) – P1(P120) - color components of VEPD P1(P120) – N2(N180), N2(N180), N2(N180) – P2(P230) – pattern components of VEPD

Проекции точек- схематических лиц на плоскость Х3Х4 четырехмерного пространства эмоциональной экспрессии, полученного для межпиковых амплитуд P120-N180 и N180-P230 ВПР, зарегистрированного в затылочных отведениях левого (верхний ряд), и правого (нижний ряд) полушарий головного мозга.

Проекции точек-схематических лиц на плоскость Х1Х2 четырехмерного пространства, полученного многомерным шкалированием межпиковых амплитуд P120-N180 (первый столбец), пиковых амплитуд N180 (средний столбец) и межпиковых амплитуд N180-P230 (правый столбец) вызванного потенциала различения, зарегистрированного в задне-височных отведениях левого (верхний ряд) и правого (нижний ряд) полушарий головного мозга.

Проекции точек-схематических лиц на плоскость Х1Х2 четырехмерного пространства эмоциональной экспрессии, полученного многомерным шкалированием межпиковых амплитуд P120-N180 (первый столбец), пиковых амплитуд N180 (средний столбец) и межпиковых амплитуд N180-P230 (правый столбец) вызванного потенциала различения, зарегистрированного в затылочных отведениях левого (верхний ряд), и правого (нижний ряд) полушарий.головного мозга.

The schematic diagram of neuronal network detecting line orientations on a frontal visual plane. Dual channels system of the pre-detectors provides both a sine– and cosine- transformation of the stimulus for each of orientation detectors. The detector is characterized by a specific composition of synaptic inputs which define its selectivity for a given orientation of stimulus. This structure is a base of sphericity of stimuli representation in subjective space.

Circular representation of stimuli in the cortical space Indexes of spheroid Interpeaks amplitudes N2(N180) – P2(P230) - Estimates of dissimilarities O1O2T5T6P3P4 Stress Coefficient of variation Coefficient of correlation Euclidean metrics City-block metrics

Circular representation of stimuli in the cortical space Indexes of spheroid Interpeaks amplitudes P1(P120) - N2(N180) Estimates of dissimilarities O1O2T5T6P3P4 Stress Coefficient of variation Coefficient of correlation Euclidean metrics City-block metrics