Orientation dependent modulation of apparent speed: a model based on the dynamics of feed-forward and horizontal connectivity in V1 cortex

• Published in: Vision research (Oxford) Vol. 42; no. 25; pp. 2781 - 2797
• Main Authors: Seriès, Peggy, Georges, Sébastien, Lorenceau, Jean, Frégnac, Yves
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.11.2002; Elsevier Science; Elsevier
• Subjects: Anatomical correlates of behavior; Apparent speed; Behavioral psychophysiology; Biological; Biological and medical sciences; Fundamental and applied biological sciences. Psychology; Humans; Lateral interactions; Life Sciences; Long-range horizontal connections; Models, Biological; Motion Perception; Motion Perception - physiology; Neurons; Neurons - physiology; Neurons and Cognition; Observer Variation; Orientation; Orientation - physiology; Psychology. Psychoanalysis. Psychiatry; Psychology. Psychophysiology; Reaction Time; Sensory Thresholds; Sensory Thresholds - physiology; Striate cortex; Visual Cortex; Visual Cortex - physiology; Lateral interactions; Striate cortex; Long-range horizontal connections; Apparent speed; Human; Receptive field; Visual cortex; Central nervous system; Spatial orientation; Cognition; Space perception; Velocity; Long-range horizontal connections: Apparent speed; Modulation; Vision; Perception; Mathematical model; Brain (vertebrata)
• ISSN: 0042-6989; 1878-5646; 0042-6989
• DOI: 10.1016/S0042-6989(02)00302-4

Psychophysical and physiological studies suggest that long-range horizontal connections in primary visual cortex participate in spatial integration and contour processing. Until recently, little attention has been paid to their intrinsic temporal properties. Recent physiological studies indicate, however, that the propagation of activity through long-range horizontal connections is slow, with time scales comparable to the perceptual scales involved in motion processing. Using a simple model of V1 connectivity, we explore some of the implications of this slow dynamics. The model predicts that V1 responses to a stimulus in the receptive field can be modulated by a previous stimulation, a few milliseconds to a few tens of milliseconds before, in the surround. We analyze this phenomenon and its possible consequences on speed perception, as a function of the spatio-temporal configuration of the visual inputs (relative orientation, spatial separation, temporal interval between the elements, sequence speed). We show that the dynamical interactions between feed-forward and horizontal signals in V1 can explain why the perceived speed of fast apparent motion sequences strongly depends on the orientation of their elements relative to the motion axis and can account for the range of speed for which this perceptual effect occurs (Georges, Seriès, Frégnac and Lorenceau, this issue).