Depth perception from second-order-motion stimuli yoked to head movement

AbstractWe examined whether depth perception was produced by the parallax of second-order motion (i.e., movement of non-luminance features, such as flicker, texture size modulation, or contrast modulation that moved in synchrony with lateral head movement). The results, obtained with second-order motion from a simple grating stimuli, showed that depth order was judged correctly with probabilities well above chance, but the reported depth magnitude did not co-vary with parallax magnitude. When we used a complex spatial pattern for which feature tracking was difficult, the accuracy of depth-order judgments descended to chance level. Our results suggest that the visual system (a) can detect the correct depth order by tracking a relative shift in the salient features of a stimulus pattern, but (b) cannot determine depth magnitude from a velocity field given by second-order-motion stimuli

Mechanical Responses of Rabbit Superior Rectus Muscle. Acetyleholine Contracture of Depolarized Muscle by Potassium

The effect of extracellular K ions on ACh contracture of rabbit superior rectus muscle was studied, and the following results were obtained. 1) A transient response was elicited by 120.8 mM K, and transient and sustained responses were induced by 10-4 g/m? ACh. 2) K-contractures in the Ringer solution containig concentrations ranging from 43.4 to 101.4 mM K ions consisted of transient and sustained tensions. The extent of the sustained tension decreased with increasing of concentration of K. 3) Contracture was elicited by ACh in 43.4-101.4 mM K Ringer solution. The extent of the contracture decreased with increasing of concentration of K, and the contracture nearly disappeared at 101.4 mM K. 4) The contracture was again produced by ACh on higher K-concentrations (above 120.8 mM) and was slow and sustained. The contracture failed in the absence of calcium and was markedly inhibited by d-tubocurarine. 5) The second phase of control ACh contracture disappeared in Ca-defficient medium and the control ACh contracture was completely inhibited by d-tubocurarine

Shot Noise Induced by Nonequilibrium Spin Accumulation

When an electric current passes across a potential barrier, the partition process of electrons at the barrier gives rise to the shot noise, reflecting the discrete nature of the electric charge. Here we report the observation of excess shot noise connected with a spin current which is induced by a nonequilibrium spin accumulation in an all-semiconductor lateral spin-valve device. We find that this excess shot noise is proportional to the spin current. Additionally, we determine quantitatively the spin-injection-induced electron temperature by measuring the current noise. Our experiments show that spin accumulation driven shot noise provides a novel means of investigating nonequilibrium spin transport.Comment: 5 pages and Supplemental Materia