Perceptual Experience of Visual Motion Activates hMT+ Independently From the Physical Reality: fMRI Insights From the Looming Pinna Figure

The human motion processing area, hMT+, has been labeled the critical neural area for processing of real and illusory visual motion in radial 2D patterns. However, the activation in hMT+ during perception of illusory rotation in the looming double-circular Pinna Figure (PF) generated in 3D space has not been observed yet. To do so, an optic-flow like motion of rings (looming) in PF was generated on a computer screen. A psychophysically precise nulling procedure allowed quantifying the individual amount of the perceived illusory rotation in PF (PI) for each participant. The interpolation of the individual illusory motion parameters created a subjectively non-rotating PF and a physically rotating control stimulus of identical rotary strength as the PI. The physically rotating control was a double-circular figure which diverged from PF only in its arrangement of luminance gradients. In a 3-Tesla scanner, participants were presented with a random order of rotating and non-rotating figures (illusory, real, no rotation, and nulled PI). Both types, illusory and real rotation, when equal in perceptual strength for the observer, were found to be processed by hMT+.

Linear increase in glycolytic activity through the cell cycle of schizosaccharomyces pombe

The glycolytic activity of 3 different synchronous system in S. pombe was studied. Synchronous cultures were produced by a selection procedure, by cyclic heat treatment, or by cloning cells from an exponentially multiplying culture. In all experiments a complex medium with 3% glucose was used. The glycolytic activity was recorded with a gasometric method, the gradient diver. A single cell in exponential growth or a small number of synchronized cells were placed in ampulla divers in which the cells progressed undistrubed through a number of cycles. An ampulla diver is in principle a narrow pipette by which a single or a few cells are removed from the mother culture. It serves next as an axenic growth chamber and at the same time as a gasometer. The divers were placed in linear saline density gradients and the gaseous exchanges taking place in the divers resulted in migration of the divers. The migration rate is a measure of the glycolytic activity of the cells. Our results show that the glycolytic activity increases in a linear fashion between sucessive divisions. The rate of increase doubles at each division. This true in all 3 synchronous systems, and we take this as an indication that the cell cycles of heat-synchronized cells do not deviate seriously from the normal.