Regions of Mid-level Human Visual Cortex Sensitive to the Global Coherence of Local Image Patches

The global structural arrangement and spatial layout of the visual environment must be derived from the integration of local signals represented in the lower tiers of the visual system. This interaction between the spatially local and global properties of visual stimulation underlies many of our visual capacities, and how this is achieved in the brain is a central question for visual and cognitive neuroscience. Here, we examine the sensitivity of regions of the posterior human brain to the global coordination of spatially displaced naturalistic image patches. We presented observers with image patches in two circular apertures to the left and right of central fixation, with the patches drawn from either the same (coherent condition) or different (noncoherent condition) extended image. Using fMRI at 7T (n = 5), we find that global coherence affected signal amplitude in regions of dorsal mid-level cortex. Furthermore, we find that extensive regions of mid-level visual cortex contained information in their local activity pattern that could discriminate coherent and noncoherent stimuli. These findings indicate that the global coordination of local naturalistic image information has important consequences for the processing in human mid-level visual cortex.

THE SOLITARY WAVE MODEL OF SUPERFLUIDITY

We propose the solitary wave model of superfluidity. According to harmonic oscillator model of quasi-lattice of liquid, it is proven that superfluid domains (SD) exist in He liquid, in which the resistanceless motion of liquid molecules (LM) can be carry out. At temperature lower than T c, all SD connect with each other and superflow in whole liquid takes place. Applying Toda's potential, under continuous conditions, we obtain the motion equation of LM, and its exact solution. Substituting these results into Schrödinger equation of LM, we can prove the existence of solitary waves of LM and the non-linear Schrödinger equation of LM. The motion of solitons of LM leads to a superflow. On the basis of coherent condition of wave of LM, we derive the formula of transition temperature Tc of superfluidity. From the formula, the relation of the onset temperature Tc of superflow on inert layers is explained.

Influence of motion on chromatic detection

Intense scrutiny has been focused on whether chromatic stimuli contribute to motion perception. The present study considers a related but different question: how does motion affect chromatic detection? Detection thresholds were measured for a disk that underwent a brief (13.3 ms) chromatic change in the L/(L+M) chromatic direction. The disk's presentation sequence and speed (0–16 deg/s) were manipulated. In the coherent presentation sequence, the disk moved smoothly along a circular path centered on the fixation point. In the random presentation sequence, the disk appeared randomly at positions along the circular path. In both types of sequences, the disk underwent a brief chromatic change midway through the temporal presentation sequence. Threshold was elevated in the coherent condition compared to the random condition, and threshold decreased with an increase in speed. The threshold elevation observed in the coherent presentation sequence can be accounted for by temporal integration. The decrease in threshold with an increase in speed can be accounted for by spatial integration. The results, therefore, can be explained by spatiotemporal integration, without invoking a neural mechanism specialized for motion.

Determination of the coherent condition for the scattering of an acoustic wave with an arbitrarily shaped wavefront by a curved area

The investigation of wave scattering has become one of the most important and urgent problems of seismology and seismic prospecting. Layered media, the traditional objects of seismic investigations, have physical properties which slowly change across certain smooth and extended surfaces.