Transient Increase in Zn2+ in Hippocampal CA1 Pyramidal Neurons Causes Reversible Memory Deficit

The translocation of synaptic Zn2+ to the cytosolic compartment has been studied to understand Zn2+ neurotoxicity in neurological diseases. However, it is unknown whether the moderate increase in Zn2+ in the cytosolic compartment affects memory processing in the hippocampus. In the present study, the moderate increase in cytosolic Zn2+ in the hippocampus was induced with clioquinol (CQ), a zinc ionophore. Zn2+ delivery by Zn-CQ transiently attenuated CA1 long-term potentiation (LTP) in hippocampal slices prepared 2 h after i.p. injection of Zn-CQ into rats, when intracellular Zn2+ levels was transiently increased in the CA1 pyramidal cell layer, followed by object recognition memory deficit. Object recognition memory was transiently impaired 30 min after injection of ZnCl2 into the CA1, but not after injection into the dentate gyrus that did not significantly increase intracellular Zn2+ in the granule cell layer of the dentate gyrus. Object recognition memory deficit may be linked to the preferential increase in Zn2+ and/or the preferential vulnerability to Zn2+ in CA1 pyramidal neurons. In the case of the cytosolic increase in endogenous Zn2+ in the CA1 induced by 100 mM KCl, furthermore, object recognition memory was also transiently impaired, while ameliorated by co-injection of CaEDTA to block the increase in cytosolic Zn2+. The present study indicates that the transient increase in cytosolic Zn2+ in CA1 pyramidal neurons reversibly impairs object recognition memory

High-speed gaze controller for millisecond-order pan/tilt camera

Abstract—We developed an optical high-speed gaze con-troller, called the “Saccade Mirror”, and used it to realize a high-speed pan/tilt camera with a high-speed image processor. Generally, in a pan/tilt camera, the gaze is controlled mechani-cally by rotational actuators. However, because pan/tilt cameras will be expected to use high-speed image processing ( 1000 fps), sufficiently high-speed performance of the gaze controller, comparable to the high frame rate, cannot be obtained with the usual method. In our system, the camera itself was fixed, and an external Saccade Mirror subsystem was used for optical gaze control. An arbitrary gaze direction within 30 deg could be achieved in less than 3.5 ms. I

Motile Cell Galvanotaxis Control Using High-Speed Tracking System

We propose a control system of motile cells. Our goal is to construct a large-scale Organized Bio-Modules (OBM) in which microorganisms are controlled as micro-size smart robots in an organized way. For the first step, we have developed a visual feedback control system of Paramecium caudatum cells. Tracking method is used for observation of moving cells with high magnification. Cells swim in a chamber and their positions are measured by high-speed vision. The chamber position is visually controlled to track a specific cell. The cell motion is controlled electrically by utilizing the galvanotaxis (intrinsic reaction to electrical stimulus) of microorganisms. Experimental results of region-trapping demonstrate the possibility of the OBM system. Index Terms---Organized Bio-Modules, Galvanotaxis, Tracking, Control, Paramecium I

Microrobotic Control of Paramecium Cells Using Galvanotaxis

Our goal is to control microorganisms as microscale smart robots for various applications. In this paper, we introduce two approaches: a novel visual feedback control system for Paramecium cells and a dynamics model of Paramecium galvanotaxis (intrinsic reaction to electrical stimulus) for procise actuation. In the former part, we propose a microrobotic control system of cells using high-speed tracking. we have controlled Paramecium cells by utilizing the galvanotaxis. Experimental results for periodic zigzag motion and trapping within a small region 1 mm wide demonstrate the possibility of using microorganisms as micromachines. In the latter part, dynamics model of galvanotaxis. we construct a novel model of galvanotaxis as a minimal step to utilizing Paramecium cells as micro-robots. Bumerical experiments for our model demonstrate realistic behaviors, such as U-turn motions, like those of real cells