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Recent methods for motor cortical decoding have demonstrated relatively accurate reconstructions of hand trajectory from small populations of neurons in primary motor cortex. Decoding results are often reported only for periods when the subject is attending to the task. In a neural prosthetic interface, however, the subject must be able to switch between controlling a device or performing other mental...
Nowadays, circulatory support has become a common practice in medicine and a standard in the treatments of cardio vascular disease (CVD). A new pneumatic ventricular assist device (VAD) has been developed in Mexico City. This paper shows the first results of acute in-vivo trials, intended to verify the new system for providing physiological flows and pressures. Two VADs were implanted to as right...
Current implantable LVADs are bulky and expensive. They all require high-risk surgery for insertion including a need for a heart/lung machine and complex connection to the heart or major blood vessels. This paper presents a newly designed "plug and play" transventricle LVAD that can be plugged into the circulation easily and work instantly with no complicated surgical procedure, no prime,...
The authors have been developing a newly-designed totally-implantable artificial myocardium using a covalent shape-memory alloy fibre (Biometalreg, Toki Corporation), which is attached onto the ventricular wall and is also capable of supporting the natural ventricular contraction. This mechanical system consists of a contraction assistive device, which is made of Ti-Ni alloy. And the phenomenon of...
This article presents an analysis of the information rate of neural spike trains in an auditory nerve fiber (ANF) model stimulated extracellularly by sinusoidal electric stimuli under the case where a high-rate pulsatile waveform is presented as a conditioner for increasing the across-fiber-independency, i.e., desynchronization. In the computer simulation, stimulus current waveforms were presented...
Brain machine interface development typically falls into two arenas, invasive extracellular recording and non-invasive electroencephalogram recording methods. The relationship between action potentials and field potentials is not well understood, and investigation of interrelationships may improve design of neuroprosthetic control systems. Rats were trained on a motor learning task whereby they had...
The clinical management of skeletal trauma and disease relies on radiographic imaging to infer bone quality. However, bone strength does not necessarily correlate well with image intensity. There is a need for a safe and convenient way to measure bone strength in situ. This paper presents a new technique to directly measure bone strength in situ at a microlevel scale through a microelectromechanical...
A neural sensor with novel structure and capable of double side recordings has been designed and fabricated using surface micromachining technique. Dry-etch benzocyclobutene (BCB) was selected as the substrate and packaging material for its excellent electrical, mechanical and thermal properties. Positive photoresist (AZ4620) was used as the sacrificial layer during the formation of backside recording...
Recent advances in tissue-engineered cartilage open the door to new clinical treatments of joint lesions. Common to all therapies with in-vitro engineered autografts is the need for optimal fit of the construct, to allow screwless implantation and optimal integration into the live joint. Computer assisted surgery techniques are prime candidates to ensure the required accuracy while at the same time...
There is a novel method for creating a 2-d parameterized finite element model of the human femur with matching artificial hip joint based on X-ray image before the hip joint replacement surgery. It can help us to evaluate the selected appropriate hip joint prosthesis
Wavelet entropy (WE), a new method of complexity measure for non-stationary signals, was used to investigate the dynamic features of rat EEGs under three vigilance states. The EEGs of the freely moving rats were recorded with implanted electrodes and were decomposed into four components of delta, theta, alpha and beta by using multi-resolution wavelet transform. Then, the wavelet entropy curves were...
Nowadays, computer assisted orthopedic planning and navigation systems have been recognized as an important tool that helps surgeons. Various systems have been developed so far, but most of them use non-standard formalisms and techniques. As a result there are no standard concepts for implant and tool management or data formats to store information for use in 3D planning and navigation systems. We...
A microfabricated and fully-implantable coil for use as a power and data transfer component for retinal prostheses is presented. Compared with traditional hand-made ocular coils, this parylene-based device is thin and flexible with 10 turns of thin-film metal wires and a thickness of less than 10 mum. In addition, the entire coil structure can be heat-formed on a mold to match the eye's curvature...
Subretinal prosthesis is one kind of retinal prosthesis, which means that a microimplant based on MEMS technology is inserted in the subretinal space to stimulate the optic nerve and elicit an electrical-evoked response on the cortical region. The subretinal implant is made up of extraocular part and intraocular part. As an important part, the latter consists of accessorial setting and stimulation...
This paper describes a low-profile three-dimensional silicon/parylene microelectrode array as basis for practical neural prostheses for use in the central nervous system. The circuit areas of the silicon probes, containing mixed-signal CMOS circuitry for neural stimulation/recording, can be folded over to reduce the overall height of the microassembled array above the cortical surface. The low-profile...
Resonance based radar target detection has been applied to ground penetrating radar (GPR) applications for the detection and recognition of landmines. Target detection is achieved by searching for certain target dependent complex natural resonances (CNRs), which could be considered as a feature set for identification. In this paper, detection of a hip prosthesis under human tissues using resonance...
Hybrid cochlear implants would integrate electric and acoustic auditory stimulation into a single unit to rehabilitate patients with sensori-neural hearing loss. Conceptually, hybrid cochlear implants consist of an electrode array, as in traditional cochlear implants, and an acoustic microactuator to generate pressure waves inside the cochlea. To enable hybrid cochlear implants, one must develop acoustic...
We report the development of an implantable multifunctional (glucose and cholesterol) needle type biosensor with integrated RF wireless circuitry for continuous in vivo monitoring of metabolites during short term stays in emergency room or intensive care unit. Silicon-based MEMS technologies are used for the fabrication of micro needle sensors. The whole device is covered by a biocompatible Parylene...
Advanced array processing techniques are becoming an indispensable requirement for integrating the rapid developments in wireless high-density electronic interfaces to the central nervous system with computational neuroscience. This work aims at describing a systems approach for latency reduction in telemetry-linked brain machine interfaces to enable real-time transmission of high volumes of neural...
We adopt a system theoretic approach and explore the model of retinal ganglion cells as linear filters followed by a maximum-likelihood Bayesian predictor. We evaluate the model by using cross-validation, i.e., first the model parameters are estimated using a training set, and then the prediction error is computed (by comparing the stochastic rate predicted by the model with the rate code of the response)...
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