Multichannel surface recordings on the visual cortex: implications for a neuroprosthesis

Chelvanayagam, David K.; Vickery, Richard M.; Kirkcaldie, Matthew; Coroneo, Minas T.; Morley, John W.

doi:10.1088/1741-2560/5/2/003

Cited by 9 publications

(6 citation statements)

References 24 publications

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“…18 Most of these reports were feasibility studies and made use of normally sighted animals, which may not be representative for human visual prosthesis users. A limited number of reports describe eVEPs in animal models of retinal degeneration, [19][20][21][22] while to our knowledge only three reports exist that describe eVEPs obtained in humans with retinal degeneration.…”

mentioning

confidence: 99%

Electrically Elicited Visual Evoked Potentials in Argus II Retinal Implant Wearers

Stronks

Dagnelie

2013

Invest. Ophthalmol. Vis. Sci.

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PURPOSE. We characterized electrically elicited visual evoked potentials (eVEPs) in Argus II retinal implant wearers.METHODS. eVEPs were recorded in four subjects, and analyzed by determining amplitude and latency of the first two positive peaks (P 1 and P 2 ). Subjects provided subjective feedback by rating the brightness and size of the phosphenes. We established eVEP input-output relationships, eVEP variability between and within subjects, the effect of stimulating different areas of the retina, and the maximal pulse rate to record eVEPs reliably.RESULTS. eVEP waveforms had low signal-to-noise ratios, requiring long recording times and substantial signal processing. Waveforms varied between subjects, but showed good reproducibility and consistent parameter dependence within subjects. P 2 amplitude overall was the most robust outcome measure and proved an accurate indicator of subjective threshold. Peak latencies showed small within-subject variability, yet their correlation with stimulus level and subjective rating were more variable than that of peak amplitudes. Pulse rates of up to 2 / 3 Hz resulted in reliable eVEP recordings. Perceived phosphene brightness declined over time, as reflected in P 1 amplitude, but not in P 2 amplitude or peak latencies. Stimulating-electrode location significantly affected P 1 and P 2 amplitude and latency, but not subjective percepts.CONCLUSIONS. While recording times and signal processing are more demanding than for standard visually evoked potential (VEP) recordings, the eVEP has proven to be a reliable tool to verify retinal implant functionality. eVEPs correlated with various stimulus parameters and with perceptual ratings. In view of these findings, eVEPs may become an important tool in functional investigations of retinal prostheses. (ClinicalTrials.gov number NCT00407602.) KEYWORDS: retinal implant, visual evoked potential, visual prosthesis, psychophysics DOEL. Karakterisering van elektrisch opgeroepen visueel opgewekte potentialen (eVEPs) in Argus II retina prothese gebruikers.METHODES. eVEP golfvormen werden in vier proefpersonen gemeten. De amplitude en latentie van de eerste twee positieve pieken (P 1 en P 2 ) werd gecorreleerd met stimulusnivo en subjectief percept. eVEP variabiliteit tussen en binnen subjecten werd bepaald, alswel de maximale pulsrepetitiesnelheid waarmee betrouwbaar eVEPs opgenomen konden worden. De proefpersonen gaven een indicatie van hun subjectieve percept door de helderheid en grootte van de fosfenen te schatten.RESULTATEN. eVEP golfvormen hadden een lage signaal-ruis verhouding, wat lange opnametijden en intensieve signaalbewerking nodig maakte. Golfvormen varieerden tussen proefpersonen, maar binnen proefpersonen waren ze goed reproduceerbaar. Pieklatenties hadden een lage variabiliteit binnen een proefpersoon, maar desondanks waren de correlaties met stimulusnivo en subjectief percept ondergeschikt aan die van piekamplitude. P 2 amplitude was de meest betrouwbare uitkomstmaat en een goede schatter van de perceptieve drempel. Pulsrepeti...

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confidence: 99%

Electrically Elicited Visual Evoked Potentials in Argus II Retinal Implant Wearers

Stronks

Dagnelie

2013

Invest. Ophthalmol. Vis. Sci.

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“…), stimulation of optical pulse to primary visual cortex induced event-related neural response. Unlike the electrical stimulation of visual cortex, the OEPs prolong for hundreds milliseconds, whereas the neural response of electrical pulse is about 10ms [4]. The possible reason relies on the different mechanisms, the current injection of electrical stimulation lead short term neural activation by activation of voltage-gated ion channels of neurons abruptly [1], but the optical stimulation needs to create a temporally and spatially mediated temperature gradient to activate the neurons [9].…”

Section: Resultsmentioning

confidence: 99%

Optical stimulation of visual cortex with pulsed 620-nm red light

Hou

Mou

Shi

et al. 2011

2011 Annual International Conference of the IEEE Engineering in Medicine and Biology Society

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To explore the optical neural stimulation with visible light, 620-nm red light pulse emitted by LED was used to stimulate the left primary visual cortex of adult rat. The neural response in right primary visual cortex was recorded with a flexible microelectrode. By synchronized averaging the raw signal, optical evoked potentials (OEPs) were observed a negative wave and positive wave after optical stimuli. Furthermore, the amplitude and occurrence of the negative and positive wave were modulated by the strength and pulse width of the optical stimulus. The preliminary experiment suggested that, beyond the infrared laser, the pulse of visible light (e.g. red light) can modulate the neural activity in central nervous system.

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“…In most cases, the C1 vertebra was cut away with rongeurs to aid placement of an adapted surface multi-electrode array (sMEA; Nucleus 22 Auditory Brainstem Implant , Cochlear Limited). Details of the electrode dimensions are shown in the inset in Figure 1 , and further details of the electrode can be found in Chelvanayagam et al ( 2008 ). A flexible plastic rod held by a micromanipulator on the stereotaxic frame was lightly pressed onto the sMEA to hold it symmetrically over the brainstem midline.…”

Section: Methodsmentioning

confidence: 99%

Dorsal Column Nuclei Neural Signal Features Permit Robust Machine-Learning of Natural Tactile- and Proprioception-Dominated Stimuli

Loutit

Potas

2020

Front. Syst. Neurosci.

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Neural prostheses enable users to effect movement through a variety of actuators by translating brain signals into movement control signals. However, to achieve more natural limb movements from these devices, the restoration of somatosensory feedback is required. We used feature-learnability, a machine-learning approach, to assess signal features for their capacity to enhance decoding performance of neural signals evoked by natural tactile and proprioceptive somatosensory stimuli, recorded from the surface of the dorsal column nuclei (DCN) in urethane-anesthetized rats. The highest performing individual feature, spike amplitude, classified somatosensory DCN signals with 70% accuracy. The highest accuracy achieved was 87% using 13 features that were extracted from both high and low-frequency (LF) bands of DCN signals. In general, high-frequency (HF) features contained the most information about peripheral somatosensory events, but when features were acquired from short time-windows, classification accuracy was significantly improved by adding LF features to the feature set. We found that proprioception-dominated stimuli generalize across animals better than tactile-dominated stimuli, and we demonstrate how information that signal features contribute to neural decoding changes over the time-course of dynamic somatosensory events. These findings may inform the biomimetic design of artificial stimuli that can activate the DCN to substitute somatosensory feedback. Although, we investigated somatosensory structures, the feature set we investigated may also prove useful for decoding other (e.g., motor) neural signals.

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Multichannel surface recordings on the visual cortex: implications for a neuroprosthesis

Cited by 9 publications

References 24 publications

Electrically Elicited Visual Evoked Potentials in Argus II Retinal Implant Wearers

Electrically Elicited Visual Evoked Potentials in Argus II Retinal Implant Wearers

Optical stimulation of visual cortex with pulsed 620-nm red light

Dorsal Column Nuclei Neural Signal Features Permit Robust Machine-Learning of Natural Tactile- and Proprioception-Dominated Stimuli

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