抄録
Visual motion is detected by low-level (energy-based) and high-level (feature-based) mechanisms. Initial Radial Flow Vergence responses (RFV) were elicited on a monkey by applying radial flow motion (quater-wavelength steps at 10 ms intervals) to a concentric circular sine-wave pattern. Expansion motion induced a convergence response; and contraction motion induced divergence response. When we used a square-wave concentric circular pattern which lacked the fundamental ("missing fundamental stimulus"), we found the opposite directional response to that obtained from the sine-wave pattern stimulus. The missing fundamental pattern including the strongest Fourier component (3rd harmonic), underwent the reverse radial motion. Eye movements were recorded with search coils. The radial motion began after the subject had fixated on the center of the pattern (<750ms) and lasted for 200 ms (=20 frames). The earliest RFV had short latency (expansion of the pattern resulted in divergent eye movements and vice versa). These data indicate that the earliest RFV and the associated perceived radial flow depend on the local Fourier components of the radial flow, which is consistent with a local motion-energy sensing mechanism. [J Physiol Sci. 2007;57 Suppl:S69]
