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TitleCreatorDescriptionSubjectDate
101Characterizing growth patterns in longitudinal MRI using image contrastCharacterizing growth patterns in longitudinal MRI using image contrastVardhan, AvantikaUnderstanding the growth patterns of the early brain is crucial to the study of neuro-development. In the early stages of brain growth, a rapid sequence of biophysical and chemical processes take place. A crucial component of these processes, known as myelination, consists of the formation of a myel...2014-01-01
102Circuits for local and global signal integration in primary visual cortexCircuits for local and global signal integration in primary visual cortexAngelucci, Alessandra; Lund, Jennifer S.Contrast-dependent changes in spatial summation and contextual modulation of primary visual cortex (V1) neuron responses to stimulation of their receptive field reveal long-distance integration of visual signals within V1, well beyond the classical receptive field (cRF) of single neurons. To identif...Primary Visual Cortex; Extrastriate Cortex; Feed-back Connections; Lateral Connections; SUrround Modulation; Macaque2002-10-01
103Classification of action potentials in multi unit intrafascicular recordings using neural network pattern recognition techniquesClassification of action potentials in multi unit intrafascicular recordings using neural network pattern recognition techniquesHorch, Kenneth W.Neural network pattern-recognition techniques were applied to the problem of identifying the sources of action potentials in multi-unit neural recordings made from intrafascicular electrodes implanted in cats. The network was a three-layer connectionist machine that used digitized action potenti...Intrafascicular electrodes; Multi-unit neural activity; Artificial neural networks1994
104Closed loop control of ankle position using muscle afferent feedback with functional neuromuscular stimulationClosed loop control of ankle position using muscle afferent feedback with functional neuromuscular stimulationHorch, Kenneth W.This paper describes a closed-loop functional neuromuscular stimulation system that uses afferent neural activity from muscle spindle fibers as feedback for controlling position of the ankle joint. Ankle extension against a load was effected by neural stimulation through a dual channel intrafasc...Neuromuscular stimulation; Functional neuromuscular stimulation (FNS); Neural electrodes1996
105Selective activation of functional muscle groups through stimulation of spinal motor poolsSelective activation of functional muscle groups through stimulation of spinal motor poolsHorch, Kenneth W.A microelectrode was used to stimulate motor neurons in the lumbo-sacral spinal cord of adult cats. Consistent with spinal cord anatomical studies, we found that the motor neurons responsible for activation of individual muscle groups are situated together in specific areas of the cord, forming mot...Spinal motor pools1993
106Selective activation of muscle groups in the feline hindlimb thorough electrical microstimulation of the ventral lumbo-sacral spinal cordSelective activation of muscle groups in the feline hindlimb thorough electrical microstimulation of the ventral lumbo-sacral spinal cordHorch, Kenneth W.Selective activation of muscle groups in the feline hindlimb by electrical stimulation of the ventral lumbo-sacral spinal cord was investigated. Spinal cord segments L5 to S1 were mapped using a penetrating tungsten needle electrode. Locations that produced isolated contraction of quadriceps, ti...Functional electrical stimulation; Motor pools; Spinal chord stimulation2000
107Laser diode coherence length variation with drive current: a tool for dispersion measurementsLaser diode coherence length variation with drive current: a tool for dispersion measurementsChristensen, Douglas A.A visible light (670nm) laser diode was used as a variable coherence length source to measure dispersion characteristics in single-mode fibers. The diode's spectral width, measured against increasing drive current, was found to change from about 16 nanometers to less than 0.2 nanometer. The corresp...Laser diode; Fiber interferometry1992
108Extending the two-dimensional FDTD method to hybrid electromagnetic systems with active and passive lumped elementsExtending the two-dimensional FDTD method to hybrid electromagnetic systems with active and passive lumped elementsChristensen, Douglas A.This paper extends the finite-difference time-domain (FDTD) method to include distributed electromagnetic systems with lumped elements (a hybrid system) and voltage and current sources. FDTD equations that include nonlinear elements like diodes and transistors are derived. Calculation of driving-p...Finite-difference time-domain method; Lumped elements1992-04
109FDTD modeling in the design of optical chemical sensor structuresFDTD modeling in the design of optical chemical sensor structuresChristensen, Douglas A.The finite-difference time-domain method (FDTD) is a numerical technique for solving Maxwell's equations in a discretized space and time frame. It has been used extensively in the analysis of electrically large structures in the microwave domain, but has only recently been applied to optical proble...Finite-difference time-domain method; Immunochemical fluorosensors; Planar waveguides1991
110Microfabricated cylindrical multielectrodes for neural stimulationMicrofabricated cylindrical multielectrodes for neural stimulationHorch, Kenneth W.The effects of spinal cord injuries are likely to be ameliorated with the help of functional electrical stimulation of the spinal cord, a technique that may benefit from a new style of electrode: the cylindrical multielectrode. This paper describes the specifications for, fabrication techniques for...Cylindrical multielectrode; Depth electrodes; Impedance testing; Microelectromechanical systems (MEMS); Microstimulation; Impedance testing; Neural prosthesis2006-02
111Mitigating spinal cord injuryMitigating spinal cord injuryJenson, Justin Michael; Bock, Susan C.How would your life change if you became one of the 15,000 Americans to suffer a spinal cord injury this year? Trauma to the spinal cord causes immediate loss of function below the level of the injury. Then, in the hours and days after the accident, the body's secondary injury response may extend ...Trapeze Interactive Poster2010-03-15
112Pulsed Schlieren system for visualizing beams from phased-array HIFU applicatorsPulsed Schlieren system for visualizing beams from phased-array HIFU applicatorsChristensen, Douglas A.We have assembled a Schlieren system for imaging the beam patterns from HIFU transducers in water to verify the desired beam focusing and direction. It consists of a high power (65 mW) short-pulse (as short as 2 ns) laser emitting at 658 nm, a beam expander/spatial filter, water tank, 400 Jim round ...Ultrasound beam patterns; Pulsed laser; Wavefronts2007
113Comparison of robust coupling techniques for planar waveguide immunosensorsComparison of robust coupling techniques for planar waveguide immunosensorsChristensen, Douglas A.; Herron, James N.We have analyzed and fabricated two different coupling schemes to meet the requirements for a convenient means of coupling into a planar waveguide immunosensor that is relatively insensitive to beam alignment. These are the "launch" coupler and the grating coupler. Each possesses advantages and dis...Planar waveguide immunosensors; Fluorescence; Launch coupler; Grating coupler1993
114Computer-aided design of two-dimensional electric-type hyperthermia applicators using the finite-difference time-domain methodComputer-aided design of two-dimensional electric-type hyperthermia applicators using the finite-difference time-domain methodChristensen, Douglas A.A hyperthermia applicator design tool consisting of a finite-difference time-domain (FDTD) technique in combination with a graphical display of electric fields and normalized linear temperature rise is described. This technique calculates, rather than assumes, antenna current distributions; it incl...Finite-difference time-domain method; Hyperthermia applicator1991-09
115Acoustic interneurons of fiddler and ghost crabsAcoustic interneurons of fiddler and ghost crabsHorch, Kenneth W.The properties of acoustic interneurons in fiddler (Uca pugilalor and U. minax) and ghost (Ocvpade qucldrula) crabs are described, as revealed bv tests with pure tones. Three types of interneurons were present in all species: tonic, which fired for the duration of the stimulus; phasic, which fire...Acoustic crabs; Neural recording; Vibration reception1976
116Rapid clinical diagnostics assays using injection-molded planar waveguidesRapid clinical diagnostics assays using injection-molded planar waveguidesChristensen, Douglas A.; Herron, James N.The goal of our research program is to develop an evanescent wave immunoassay system that can be used in point-of-care and critical care settings. Several key attributes are required to accomplish this goal: (i) the assay system should be at least as sensitive as present day immunoassays; (ii) assay...Planar waveguides; Creatine phosphokinase MB (CK-MB); Cardiac troponin I (cTnl); Diagnostics; Evanescence; Fluorescence; Human chorionic gonadotropin (hCG)1998
117On the number and nature of regenerating myelinated axons after lesions of cutaneous nerves in the catOn the number and nature of regenerating myelinated axons after lesions of cutaneous nerves in the catHorch, Kenneth W.1. Electrophysiological and anatomical techniques were used to investigate normal and regenerating sural and posterior femoral cutaneous nerve fibres in the cat. 2. One and a half years after transection of these nerves it was found that the regenerating neurones supported multiple sprouts in the...Nerve fibres; Transection; Nerve injury1981
118Acute peripheral nerve recording characteristics of polymer-based longitudinal intrafascicular electrodesAcute peripheral nerve recording characteristics of polymer-based longitudinal intrafascicular electrodesHorch, Kenneth W.; Lawrence, Steve M.; Dhillon, Gurpreet S.We examined the recording characteristics of two different types of polymer-based longitudinal intrafascicular electrodes (LIFEs) in peripheral nerve: single-stranded (s-polyLIFEs) and multistranded (m-polyLIFEs). Recordings were also made from Pt-Ir wire-based electrodes (PtIrLIFEs) as a control. T...Sciatic Nerve; Intrafascicular Electrodes, Peripheral Nerve Recording2004
119Statistical encoding model for a primary motor cortical brain-computer interfaceStatistical encoding model for a primary motor cortical brain-computer interfaceNormann, Richard A.A number of studies of the motor system suggest that the majority of primary motor cortical neurons represent simple movement-related kinematic and dynamic quantities in their time-varying activity patterns. An example of such an encoding relationship is the cosine tuning of firing rate with respect...Discrete Distribution; LN Model; Neural Decoding; Neuroprosthetics; Sequential Monte-Carlo Filter2005
120Coding of position by simultaneously recorded sensory neurones in the cat dorsal root ganglionCoding of position by simultaneously recorded sensory neurones in the cat dorsal root ganglionNormann, Richard A.; Shoham, ShyMuscle, cutaneous and joint afferents continuously signal information about the position and movement of individual joints. How does the nervous system extract more global information, for example about the position of the foot in space? To study this question we used microelectrode arrays to record...Cats; Sensory Neurones; Movement; Limb Position2004
121Visual Neuroprosthetics: Functional Vision for the BlindVisual Neuroprosthetics: Functional Vision for the BlindNormann, Richard A.Resent progress in materials and microfabrication technologies have allowed researchers to reconsider the prospect of providing a useful visual sense to the profoundly blind. This will be accomplished by electrically stimulating their visual systems via an array of implanted microelectrodes. T...Visual Neuroprosthetics; Vision; Blindness1995-01
122Oscillations in rod and horizontal cell membrane potential: evidence for feed-back to rods in the vertebrate retinaOscillations in rod and horizontal cell membrane potential: evidence for feed-back to rods in the vertebrate retinaNormann, Richard A.1. Rods and horizontal cells were studied with intracellular recordings in the retina of the toad, Bufo marinus; 161 cells were from the eyecup preparation and thirty were from the isolated perfused retina. 2. Of these cells, 39% exhibited either transient or sustained oscillations of membrane poten...Retina; Photoreceptors; Toads; Adaptation, Ocular1976
123Information extraction from peripheral nervesInformation extraction from peripheral nervesHorch, Kenneth W.This work is directed toward providing better rehabilitation for people suffering from somatosensory loss and paralysis due to spinal cord injury, head trauma, or stroke. The goal of this project is to demonstrate that information suitable for controlling prosthetic devices, modulating functional el...Peripheral nerve; Neural recordings; Intrafascicular electrodes1991
124Direct neural sensory feedback and control of a prosthetic armDirect neural sensory feedback and control of a prosthetic armHorch, Kenneth W.; Dhillon, Gurpreet S.Evidence indicates that user acceptance of modern artificial limbs by amputees would be significantly enhanced by a system that provides appropriate, graded, distally referred sensations of touch and joint movement, and that the functionality of limb prostheses would be improved by a more natural co...Peripheral Nerve Implant; Prosthetic Limb Control; Sensory Feedback2005-12
125Proposed specifications for a lumbar spinal cord electrode array for control of lower extremities in paraplegiaProposed specifications for a lumbar spinal cord electrode array for control of lower extremities in paraplegiaHorch, Kenneth W.The goal of the study was to provide specifications for a stimulating electrode array to be implanted in the lumbosacral spinal cord as part of a functional neuromuscular stimulation (FNS) system for control of lower extremity muscles in paralyzed individuals. Dual channel stimulation of the qua...Stimulating electrode array; FNS; Functional neuromuscular stimulation1997
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