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So R.,Institute for Infocomm Research | Xu Z.,Institute for Infocomm Research | Libedinsky C.,Singapore Institute for Clinical science SICS | Libedinsky C.,Singapore Institute for Neurotechnology SINAPSE | And 5 more authors.
International IEEE/EMBS Conference on Neural Engineering, NER | Year: 2015

Using a brain-machine interface (BMI), a non-human primate (NHP) was trained to control a mobile robotic platform in real time using spike activity from the motor cortex, enabling self-motion through brain-control. The decoding model was initially trained using neural signals recorded when the NHP controlled the platform using a joystick. Using this decoding model, we compared the performance of the BMI during brain control with and without the use of a dummy joystick, and found that the success ratio dropped by 40% and time taken increased by 45% when the dummy joystick was removed. Performance during full brain control was only restored after a recalibration of the decoding model. We aimed to understand the differences in the underlying neural representations of movement intentions with and without the use of a dummy joystick, and showed that there were significant changes in both directional tuning, as well as global firing rates. These results indicate that the strategies used by the NHP for self-motion were different depending on whether a dummy joystick was present. We propose that a recalibration of the decoding model is an important step during the implementation of a BMI system for self-motion. © 2015 IEEE. Source


Ong W.-Y.,National University of Singapore | Tanaka K.,National University of Singapore | Dawe G.S.,National University of Singapore | Dawe G.S.,Singapore Institute for Neurotechnology SINAPSE | And 2 more authors.
Journal of Alzheimer's Disease | Year: 2013

Progress is being made in identifying possible pathogenic factors and novel genes in the development of Alzheimer's disease (AD). Many of these could contribute to 'slow excitotoxicity', defined as neuronal loss due to overexcitation as a consequence of decreased energy production due, for instance, to changes in insulin receptor signaling; or receptor abnormalities, such as tau-induced alterations the N-methyl-D-aspartate (NMDA) receptor phosphorylation. As a result, glutamate becomes neurotoxic at concentrations that normally show no toxicity. In AD, NMDA receptors are overexcited by glutamate in a tonic, rather than a phasic manner. Moreover, in prodromal AD subjects, functional MRI reveals an increase in neural network activities relative to baseline, rather than loss of activity. This may be an attempt to compensate for reduced number of neurons, or reflect ongoing slow excitotoxicity. This article reviews possible links between AD pathogenic factors such as AβPP/Aβ and tau; novel risk genes including clusterin, phosphatidylinositol-binding clathrin assembly protein, complement receptor 1, bridging integrator 1, ATP-binding cassette transporter 7, membrane-spanning 4-domains subfamily A, CD2-associated protein, sialic acid-binding immunoglobulin-like lectin, and ephrin receptor A1; metabolic changes including insulin resistance and hypercholesterolemia; lipid changes including alterations in brain phospholipids, cholesterol and ceramides; glial changes affecting microglia and astrocytes; alterations in brain iron metallome and oxidative stress; and slow excitotoxicity. Better understanding of the possible molecular links between pathogenic factors and slow excitotoxicity could inform our understanding of the disease, and pave the way towards new therapeutic strategies for AD. © 2013 - IOS Press and the authors. All rights reserved. Source


Ramji R.,National University of Singapore | Bhagat A.A.S.,Clearbridge Biomeidics Pte Ltd. | Lim C.T.,National University of Singapore | Chen C.-H.,National University of Singapore | Chen C.-H.,Singapore Institute for Neurotechnology SINAPSE
17th International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2013 | Year: 2013

Single cell intracellular protein studies have gained importance over the recent years due to their ability to differentiate data obtained from ensemble measurements. We demonstrated for the first time, the ability to compartmentalize cells inside droplets and study a dynamic kinase signaling process which is triggered by activation of a tyrosine kinase receptor upon ligand binding at the cell surface. In addition, we also reported spatial ordering of cells using inertial focusing through pinched microchannel structures. This design allows us to encapsulate single cells inside the droplets by breaking cell aggregates during their passage through the pinch structure. Source


Xiang Z.,National University of Singapore | Yen S.-C.,National University of Singapore | Sheshadri S.,Singapore Institute for Neurotechnology SINAPSE | Xue N.,Agency for Science, Technology and Research Singapore | And 4 more authors.
Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS | Year: 2015

Various peripheral nerve interfaces have been developed in the last decades and transferred into neuroscientific researches or clinical applications. In this study, we present a novel flexible neural ribbon electrode that can achieve self-adaption to nerves in various diameters and have three dimensional (3D) contacts. Impedance spectroscopy of the neural ribbon electrode was carried out to determine its electrochemical characteristics during the recording. The recording capability of the neural ribbon on sciatic nerves with different diameter was demonstrated by successful signal acquisitions. © 2015 IEEE. Source


Delbruck T.,ETH Zurich | Pfeiffer M.,ETH Zurich | Juston R.,Aix - Marseille University | Orchard G.,Singapore Institute for Neurotechnology SINAPSE | And 3 more authors.
Proceedings - IEEE International Symposium on Circuits and Systems | Year: 2015

This paper describes an open-source implementation of an event-based dynamic and active pixel vision sensor (DAVIS) for racing human vs. computer on a slot car track. The DAVIS is mounted in 'eye-of-god' view. The DAVIS image frames are only used for setup and are subsequently turned off because they are not needed. The dynamic vision sensor (DVS) events are then used to track both the human and computer controlled cars. The precise control of throttle and braking afforded by the low latency of the sensor output enables consistent outperformance of human drivers at a laptop CPU load of <3% and update rate of 666Hz. The sparse output of the DVS event stream results in a data rate that is about 1000 times smaller than from a frame-based camera with the same resolution and update rate. The scaled average lap speed of the 1/64 scale cars is about 450km/h which is twice as fast as the fastest Formula 1 lap speed. A feedbackcontroller mode allows competitive racing by slowing the computer controlled car when it is ahead of the human. In tests of human vs. computer racing the computer still won more than 80% of the races. © 2015 IEEE. Source

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