Transretinal electrical stimulation by an intrascleral multichannel electrode array in rabbit eyes

Towards a distributed neural interface, consisting of multiple miniaturized implants, for interfacing with large-scale neuronal ensembles over large brain areas, this paper presents a mm-sized free-floating wirelessly-powered implantable opto-electro stimulation (FF-WIOS2) device equipped with 16-ch optical and 4-ch electrical stimulation for reconfigurable neuromodulation. The FF-WIOS2 is wirelessly powered and controlled through a 3-coil inductive link at 60 MHz. The FF-WIOS2 receives stimulation parameters via on-off keying (OOK) while sending its rectified voltage information to an external headstage for closed-loop power control (CLPC) via load-shift-keying (LSK). The FF-WIOS2 system-on-chip (SoC), fabricated in a 0.35-µm standard CMOS process, employs switched-capacitor-based stimulation (SCS) architecture to provide large instantaneous current needed for surpassing the optical stimulation threshold. The SCS charger charges an off-chip capacitor up to 5 V at 37% efficiency. At the onset of stimulation, the capacitor delivers charge with peak current in 1.7–12 mA range to a micro-LED (µLED) array for optical stimulation or 100–700 μA range to a micro-electrode array (MEA) for biphasic electrical stimulation. Active and passive charge balancing circuits are activated in electrical stimulation mode to ensure stimulation safety. In vivo experiments conducted on three anesthetized rats verified the efficacy of the two stimulation mechanisms. The proposed FF-WIOS2 is potentially a reconfigurable tool for performing untethered neuromodulation.

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Functional Electrical Stimulation of the Larynx with a Flexible Ribbon Electrode Array

Otolaryngology ◽

10.1177/0194599814541627a134 ◽

2014 ◽

Vol 151 (1_suppl) ◽

pp. P71-P72

Author(s):

Morgan R. Bliss ◽

Heather Wark ◽

Daniel McDonnall ◽

Marshall E. Smith

Keyword(s):

Electrical Stimulation ◽

Functional Electrical Stimulation ◽

Electrode Array ◽

Stimulation Of

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Verification of multichannel electrode array integrity by use of cross-channel correlations

Journal of Neuroscience Methods ◽

10.1016/j.jneumeth.2016.02.009 ◽

2016 ◽

Vol 263 ◽

pp. 95-102 ◽

Cited By ~ 2

Author(s):

Nicholas V. Swindale ◽

Martin A. Spacek

Keyword(s):

Electrode Array ◽

Multichannel Electrode

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Electrical Cochlear Stimulation in the Deaf Cat: Comparisons Between Psychophysical and Central Auditory Neuronal Thresholds

Journal of Neurophysiology ◽

10.1152/jn.2000.83.4.2145 ◽

2000 ◽

Vol 83 (4) ◽

pp. 2145-2162 ◽

Cited By ~ 24

Author(s):

Ralph E. Beitel ◽

Russell L. Snyder ◽

Christoph E. Schreiner ◽

Marcia W. Raggio ◽

Patricia A. Leake

Keyword(s):

Electrical Stimulation ◽

Auditory System ◽

Pulse Rate ◽

Auditory Nerve ◽

Round Window ◽

Electrode Array ◽

Scala Tympani ◽

Behavioral Thresholds ◽

Current Pulses ◽

Stimulation Of

Cochlear prostheses for electrical stimulation of the auditory nerve (“electrical hearing”) can provide auditory capacity for profoundly deaf adults and children, including in many cases a restored ability to perceive speech without visual cues. A fundamental challenge in auditory neuroscience is to understand the neural and perceptual mechanisms that make rehabilitation of hearing possible in these deaf humans. We have developed a feline behavioral model that allows us to study behavioral and physiological variables in the same deaf animals. Cats deafened by injection of ototoxic antibiotics were implanted with either a monopolar round window electrode or a multichannel scala tympani electrode array. To evaluate the effects of perceptually significant electrical stimulation of the auditory nerve on the central auditory system, an animal was trained to avoid a mild electrocutaneous shock when biphasic current pulses (0.2 ms/phase) were delivered to its implanted cochlea. Psychophysical detection thresholds and electrical auditory brain stem response (EABR) thresholds were estimated in each cat. At the conclusion of behavioral testing, acute physiological experiments were conducted, and threshold responses were recorded for single neurons and multineuronal clusters in the central nucleus of the inferior colliculus (ICC) and the primary auditory cortex (A1). Behavioral and neurophysiological thresholds were evaluated with reference to cochlear histopathology in the same deaf cats. The results of the present study include: 1) in the cats implanted with a scala tympani electrode array, the lowest ICC and A1 neural thresholds were virtually identical to the behavioral thresholds for intracochlear bipolar stimulation; 2) behavioral thresholds were lower than ICC and A1 neural thresholds in each of the cats implanted with a monopolar round window electrode; 3) EABR thresholds were higher than behavioral thresholds in all of the cats (mean difference = 6.5 dB); and 4) the cumulative number of action potentials for a sample of ICC neurons increased monotonically as a function of the amplitude and the number of stimulating biphasic pulses. This physiological result suggests that the output from the ICC may be integrated spatially across neurons and temporally integrated across pulses when the auditory nerve array is stimulated with a train of biphasic current pulses. Because behavioral thresholds were lower and reaction times were faster at a pulse rate of 30 pps compared with a pulse rate of 2 pps, spatial-temporal integration in the central auditory system was presumably reflected in psychophysical performance.

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Radiology for cochlear implants

The Journal of Laryngology & Otology ◽

10.1017/s0022215100115026 ◽

1991 ◽

Vol 105 (2) ◽

pp. 85-88 ◽

Cited By ~ 10

Author(s):

R. F. Gray ◽

R. A. Evans ◽

C. E. L. Freer ◽

H. E. Szutowicz ◽

G. F. Maskell

Keyword(s):

Cochlear Implants ◽

Electrode Array ◽

Base Line ◽

Maximum Information ◽

Cochlear Duct ◽

Plain Films ◽

Hearing Result ◽

Frequency Map ◽

Inexperienced Surgeon ◽

Multichannel Electrode

AbstractOne fifth of patients selected for cochlear implants have such bony irregularities in the cochlear duct that full insertion of a multichannel electrode array is impossible. Three cases of cochlear deafness are presented where pre- and post-operative radiology played an important part in the management.Standard CT at 2 mm cuts is compared with ultra high resolution CT at 1 mm cuts. The pitfall of poor definition is that the inexperienced surgeon may find himself unexpectedly drilling out an obliterated cochlear duct. Sections 30 degrees caudal to Reid's infra orbito-meatal base line at 1 mm intervals give maximum information for minimum radiation.Plain films show the placement of individual platinum electrode contacts in relation to the spiral ‘frequency map’ of the cochlea. This is vital information for the audiologist who has to route specific frequencies to specific sites within the ear for a good hearing result.

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