Ординатура / Офтальмология / Английские материалы / Artificial Sight Basic Research, Biomedical Engineering, and Clinical Advances_Humayun, Weiland, Chader_2007

390 Index

charge-balanced, 190, 240 current, 161, 167, 202, 203, 247,

251–252, 333

minimization of pH changes by, 235 square-wave, 370–371

stimulus, short, response to, 349–353 Pulse shape circuits, 161

Pupil, 3

Quartz substrates, 246–247

Questionnaires, 97

Radiated heat, 172 Radio frequency, 151

Radiofrequency telemetry, 203 Receivers

microelectronic, 227 wireless, 280

Recognition of objects, 107 Recording, noninvasive, 370–373 Rectification, electrical, 140–141, 175 Regulated cascade current sink, 181 Rehabilitation training, 50, 62–65 Resistive loss, 262

Resolution, visual, 92 Response amplitude, 193 Response field, 373 Response origins, 365–366 Responsivity, cross-modal, 54 Resting potential, 259

Retina, 5–9, 91, 187, 289, 308 attachment of an array to, 20–23 damaged, morphology and electrical

response of, 210 degenerate, 367–368, 374 direct stimulation of, 18

electrical stimulation of, 17–19, 357 neural network of, 265 organization of, 7

pressure effect on, 20–21 projection of, 321 response of, 357

tacking to, 20 thickness of, 9–10 vessels of, 6

Retina encoder, 114–116 tuning of, 115

Retinal cells

attraction of to electrodes, 267–269 migration of, 267–269

stimulation of, 159–162 Retinal damage, 10

Retinal detachment, 1, 6, 8, 11, 12–13, 23, 24, 25, 125, 369

diagram of, 8 risk of, 24

Retinal disease, 13–17 degenerative, 12, 13 vascular, 13

Retinal electrical simulation, 1, 72, 111, 116, 118, 126, 129, 169–186, 210, 255, 257

intraocular, 121 pulsed, 133 safety of, 119

Retinal encoder, 189

Retinal function, evaluation of, 9

Retinal ganglion cells, 31–32, 34, 35, 161, 373 axotomized, survival of, 40

death of, 43

electrical stimulation of, 333–343 localized excitation of, 39 protection of, 41

Retinal image, constructing a 3-d interpretation from, 60

Retinal implants, 19–25, 111–126 epiretinal, 111

intraocular, 227 learning, 111

Retinal implant system, 113 Retinal lesions, filling in of, 48

Retinal pigment epithelium, 6, 16, 24, 72 Retinal pigment epithelium cells, damage

of, 331

Retinal prostheses, 347 all-intraocular, 21–23

diagram of, 22 design of, 178–184 development of, 357 dual-unit, 279–303 flexibility of, 131–132

high-resolution, 129–147, 255–275 implantation of, 162–167 intraocular, 1–25

early model of, 228 materials for, 1

power used by, 131–132 size constraints of, 213 size of, 131–132

Retinal prosthetic electrodes, interaction of with neural tissue, 209–224

Retinal remodeling, progressive, 17 Retinal response to light, 195, 360

Retinal separation, 1, 6, 8, 11, 12–13, 23, 24, 25, 125, 369

Retinal stimulating arrays, 369

Retinal stimulation, 1, 72, 111, 116, 118, 126, 129, 169–186, 210, 255, 257

intraocular, 121 pulsed, 133 safety of, 119

Retinal stimulators, 172, 183–184, 369 Retinal surgery, 12–13, 19–25, 36–37 Retinal tack, 32, 117

Retinal tacking, 20 Retinal tear, risk of, 24

Retina stimulator, 112, 116–118

Retinitis pigmentosa, 11, 14, 15, 18, 71–72, 111, 112, 120, 129, 170, 188, 209, 255–256, 280, 334, 347

appearance of, 16 cell loss in, 17 patients with, 120

Reverse telemetry, 146, 184

Reverse transcriptase–polymerase chain reaction, 42

Reversibility, surgical, 2 Rods, 6

Safety, 119

Safety margin, 230 Saturation, 373

definition of, 371–372

Sclera, 4, 5, 9, 33, 162, 272, 364, 369 fenestrated, 32, 39

Scleral buckling, 1, 12 Scleral pocket, 36, 38 Scleral port, 119 Sclerotomy, 325, 327

Sensory function, role of experience in maintaining, 57–62

Sensory plasticity, 47–50 Sensory processing, 47 Sensory prostheses

early provision of

interference with cross-modal plasticity of, 63

neurophysiological advantages of, 63

interference with cross-modal processing by, 63

potential loss of cross-modal abilities with, 64

rehabilitation with, 62–65 Sensory restoration procedures, 65 Sensory system, 91

Serial resistance, 262

Serial to parallel converters, 172, 178–179 Sharpness, perception of, 124–125

Shunt regulators, 140, 141

Index 391

Sight restoration

of early blind patients, useful vision in, 61 vision improvement after, 60

Signaling mechanisms, 17 Signal intensity, 257

Signal processing, 8, 144, 151, 224, 257, 258, 355

Signal strength, 193 Signal-to-noise ratio, 152

Sign language, facial expressions in, 52 Silicon, 162

Silicone, 1, 5

Simulation experiments, 86 Simultaneous stimulation, multielectrode,

340–341, 343

Sintering of nanoparticles, 245, 246, 249 Size perception, 124

Skin effect, 139

Smearing of information across fingers, 53 Snellen notation, 92, 93

Sobel gradients, 200 Somatosensory cortex, 52, 53

Somatosensory-evoked potentials, 53 Spatial filtering, 156

Spatial frequencies, 256–266 Spatial resolution, 32, 38–39, 256 Speech perception, recovery of, 62

Speech processing after cochlear implant, 61 Spike frequency, variations in, 347

Spikes, ganglion response, 338–339, 342 short-latency, 338–340

Spike timing between retinal neurons, 348 Spike trains, 122, 347, 355, 373

Spiking, ganglion cell, early and late phases of, 352–353

Spiking activity of ganglion cells, 364 Spiking latency, 351

Spiking pattern, ganglion cell, 347, 348 Stereopsis, 92, 93

Stimulating electrodes, 32, 33, 36–37, 94 effects of reducing the size of all on charge

density of, 353 placement of, 190 platinum, 236

Stimulation

flexibility of, 135–137, 144 high-frequency, 343 indirect, 326

parameters of, 272 alteration of, 373

sequential, 319

sequential vs. simultaneous, 317 subretinal, 33

392 Index

suprachoroidal-transretinal, 31, 32–33, 151, 325–331

disadvantages of, 32 effectiveness of, 33–39 merits of, 32–33

Stimulation frequency, 337 Stimulation-induced depression of electrical

excitability, 315–319 Stimulation-induced depression of electrical

excitability, minimization of, 319 Stimulation pulses, frequency and intensity

of, 233

Stimulation voltage, 133–135 Stimulator chip, modeling of, 289–291 Stimulus current threshold, 135

Stimulus electrodes, large-scale integration, 151–167

Stimulus field

cellular targets of, 375 containment of, 372 definition of, 372

Stimulus parameters, alteration of, 373 Stimulus pulses, 337

duration of, 338–340 long, response to, 352, 353

short, response to, 349–353 Stimulus strength, 372

Subretinal implantation, 23–25, 257 diagrams of, 23, 24

Subretinal implants, 171 neuroprotective effect of, 43

Subretinal implants with perforated membranes, 255, 268

Subretinal implants with protruding electrode arrays, 255, 269

Subretinal stimulation, 33 Suprachoroidal electrodes, 35

Suprachoroidal-transretinal stimulation, 31, 32–33, 151, 325–331

disadvantages of, 32 effectiveness of, 33–39 merits of, 32–33

Surface area effective, 221–223 electrode, 221–223

Surface potential recordings, 358, 359 Surgery, 22

ab externo technique of retinal implant, 24–25

ab interno technique of retinal implant, 24–25 complications during, 25

epiretinal techniques of, 19–23 retinal, 12–13

retinal implant, 19–25

subretinal techniques of, 23–25

Surgical implantation, procedures of, 36–37 Synapses, 17

Synaptic transmission, 365 System-on-chip, 130

Tacking to the retina, 20 Tacks, retinal, 117

Tactile discrimination by the blind, 51

Tasks, every day, performance of, 96, 105–107 Telemetry

dual-band, 144–146 forward, data rate for, 137 optical, 144

single-band, 144

Temperature increases, 262, 263, 283–284, 288, 289–294

Temperature regulation, 289

Temperature rise, 262, 263, 283–284, 288, 289–294

Temporal resolution, 100 Tests, design of, 94–95 Tethering wires, 138 Tetrodotoxin, 348–353 T flip flops, 182

Thermal conductivity, 262–263 Thermal damage, 2

Thermal effects, modeling of, 279–303 Thermal elevation, 262, 263, 283–284, 288,

289–294 Thermotherapy, 15 Threshold charges, 18–19

perceptual, 120

Threshold currents, 37–38, 39, 261 phosphene generation, 308 unit-like response, 316–319, 321

Threshold detection, transceiver, 176–177 Threshold-duration effects, 338–340 Thresholds

axonal depolarization, 224 brainstem-response, 222 charge, 117, 120

charge density, 18–19, 37–38, 215–216, 264, 333–334

charge stimulation, 334

current, 18, 37–39, 120, 122, 135, 233, 261, 308, 334, 337

damage, 212 definition of, 371–372 early-spiking, 352 electrical, 316–319 electrode, 233

electrolysis, 214–215, 216, 217–218 faradaic reaction, 214–215, 222

ganglion cell activation, 352, 353 ganglion spike, 337–340

ganglion stimulation, 338–339, 343 hydrogen generation, 215, 218 membrane potential, 210

neural damage, 212, 330 neuronal depolarization, 211 neuron excitation, 211, 321 noise, 266

perceptual, 92, 122, 123, 124–125 definition of, 122

response of, 372 psychometric, 92, 98, 105 redox reaction, 220, 222, 224 stimulation, 124, 334

current and charge, 334 minimal, 123

stimulation response, 35, 131, 133, 135, 169, 253, 257, 261

stimulus current, 135 tactile, 51

thermal, 2

visual function, 102 voltage, 153, 261

Timing, stimulus pulse, 351–352 Tissue

electrical stimulation of, 252 heating of, 245

Tissue change after stimulation, 325–331 Tissue damage, 311–312

Tissue glues, 21

Tissue heating, 261–263 Tissue properties, 288–289

Tissue responses to microelectrodes, 311–321 Tissue trauma, charge-related, 212

Titanium, 161, 169 Titanium nitride, 219, 264

Touch, blind individuals’ abilities for, 51 Toxicity, 2, 213

Trabecular meshwork, 4 Tracking systems, 273–274 Training methods, 86 Transceivers, 175

Transceiver threshold detection, 176–177 Transcorneal electrical stimulation, 41–42 Transcranial magnetic stimulation, 54, 64 Transmitters, wireless, 280

Transplant procedures, 209 TTX (tetrodotoxin), 349–353

Unit-like responses, 316–319

Utah intracortical array, 311–312

Index 393

Vacuum deposition, 244

Video processing units, 132–133 Vision

artificial cat, 39

electrophysiology of, 366–378 central, restoration of, 307 electrophysiology of, 355–379 natural, electrophysiology of, 357–360 quality of, 130

testing of, 92–93

very low, assessment of, 92 Vision simulation, prosthetic, 71–89

Visual acuity, 92, 93, 97, 256, 257, 266 testing of, 103–104

Visual areas, higher, 48 Visual cortex, 52, 187, 347

early areas of, changes in, 54 monkey, 319

plasticity of, 48 reorganization of, 48 size of, 53 stimulation of, 321

testing of, 95

Visual deprivation, effects of, 47–65 Visual field, right, 52

Visual functions restoration of, 130 testing of, 91–108

design of, 94–95 limitations of, 92–94

subjective scales for, 97, 107–108 thresholds of, 102

Visual information extraction, 201–202 Visual inspection tasks, 85–86

Visual interface, 112, 114

Visually evoked potentials, 18, 34, 92–93 Visually evoked response, 18

Visual percepts, 308, 356

Visual performance, 91, 94, 95, 97, 102 Visual processing unit, 227

deterioration of, 57–62 Visual processor, 113 Visual prostheses

design of, 197–203 electronic, 209 epiretinal, 343 ICMS, 307–321

pH changes in, 227–240 resolution of, 334

Visual response, cellular origins of, 375 Visual system, anatomy and physiology of,

308–309

Visual tasks, peripheral, 52

394 Index

Vitamin A, 15

Vitrectomy, 1, 12, 19, 23, 119

pars plana, 121

partial, 24 Vitreous, 5, 13

definition of, 211 Vitreous cavity, 12 Vitreous humor, 211 Voltage, operating, 134 Voltage drops, 142 Voltage excursions, 252

Voltage pulse waveform, 154 Voltage supply, 133, 135 Voltammetry, 236, 246, 251 Voxels, 295, 298–300, 359

Waveforms, stimulus-pulse, 313, 351–352 Wireless communication, 169

Wireless data communication, 143–146 Wireless implantable bio-device interfaces,

172–178

circuits of, 174–176 design of, 173–176 simulation of, 176–178

Wireless microarray implants, 169–186 Wireless power transmission, 138–143, 169 Wireless telemetry, 292

Wireless transmission, ocular, 111 Wireless transmitters and receivers, 280

Zinc, 15

Zonules, 5