Optokinetische Wirksamkeit bewegter periodischer Muster (Nach Messungen am Rüsselkäfer Chlorophanus viridis)

Abstract

The strength of optomotor reactions has been measured by means of the Y-maze-globe method (Fig. 1). If the moving patterns are composed of vertical stripes of contrasting shades of grey the strength of reaction is a quadratic function of the difference of reflexion between the stripes (Fig. 2). This corresponds to the finding that perception of movement in the beetle’s eye results from the multiplication between stimulus intensities of adjacent ommatidia (Fig. 13). Varying velocities of a sinusoidal pattern of shades (Fig. 4) release reactions plotted in Fig. 5. The response to more complicated moving patterns like those shown in Figs. 3, 6, 11, 15 is the sum of the responses to the sinusoidal (Fourier) components involved. The relative phases of the periodic components of the patterns have no influence on the reaction (Fig. 11, 12). Under special experimental conditions, i. e. high velocity of the moving structures, the physiological response to different shades of grey are linear. In the case of very slow velocities the physiological scale of grey of the beetle’s eye is altered by an adaptation process; the medium grey changes its place from grey 50 to grey 40 (experimental black=0, white = 100). Moving irregular patterns which are composed of very fine stripes (Fig. 15 b) release reactions plottet in Fig. 16. The reaction curve has a negative part which results from a special mechanism discussed by REICHARDT und VARJÚ 4. - Most of the above experiments were designed in order to prove theoretical predictions which were derived from the correlation principle of movement perception 1, 4, 5.