Electrically-evoked Neural Activities of rd1 Mice Retinal Ganglion Cells by Repetitive Pulse Stimulation

Ryu, Sang Baek; Ye, Jang Hee; Lee, Jong Seung; Goo, Yong Sook; Kim, Chi Hyun; Kim, Kyung Hwan

doi:10.4196/kjpp.2009.13.6.443

Cited by 15 publications

(18 citation statements)

References 22 publications

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“…However, in response to a train of pulses, the response to indirect activation becomes desensitized, both for healthy (Jensen and Rizzo 2007; Ahuja et al 2008; Freeman and Fried 2011) and degenerate retina (Ryu et al 2009). Such desensitization is illustrated in Figure 4b for a rabbit retinal ganglion cell stimulated at 8Hz.…”

Section: The Response Of Retinal Neurons To Electric Stimulationmentioning

confidence: 99%

Encoding visual information in retinal ganglion cells with prosthetic stimulation

2011

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Retinal prostheses aim to restore functional vision to those blinded by outer retinal diseases using electric stimulation of surviving retinal neurons. The ability to replicate the spatiotemporal pattern of ganglion cell spike trains present under normal viewing conditions is presumably an important factor for restoring high-quality vision. In order to replicate such activity with a retinal prosthesis, it is important to consider both how visual information is encoded in ganglion cell spike trains, and how retinal neurons respond to electric stimulation. The goal of the current review is to bring together these two concepts in order to guide the development of more effective stimulation strategies. We review the experiments to date that have studied how retinal neurons respond to electric stimulation and discuss these findings in the context of known retinal signaling strategies. The results from such in vitro studies reveal the advantages and disadvantages of activating the ganglion cell directly with the electric stimulus (direct activation) as compared to activation of neurons that are presynaptic to the ganglion cell (indirect activation). While direct activation allows high temporal but low spatial resolution, indirect activation yields improved spatial resolution but poor temporal resolution. Finally, we use knowledge gained from in vitro experiments to infer the patterns of elicited activity in ongoing human trials, providing insights into some of the factors limiting the quality of prosthetic vision.

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Section: The Response Of Retinal Neurons To Electric Stimulationmentioning

confidence: 99%

Encoding visual information in retinal ganglion cells with prosthetic stimulation

2011

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“…And, the abnormal rhythmic activities were observed from both spontaneous spikes of RGCs and field potentials (i.e. slow wave component) [6]- [8], [14]. However, there have been only a few studies on the electrically stimulated RGCs of photoreceptor-degenerated retinas [5,9,15], and none of them have mentioned the effect of the aberrant 10 Hz oscillatory rhythmic activity.…”

Section: Discussionmentioning

confidence: 99%

“…The stimuli consisted of symmetric, charge-balanced biphasic voltage pulses. The pulse durations were fixed at 500 µs per phase, as was determined from the modulation behavior of the RGC responses by the pulse amplitude, to be suitable for evoking and modulating RGC responses reliably from our retinal preparations [14]. The pulse trains were applied to the stimulation electrode using a stimulus generator STG 1004 (Multichannel systems GmbH, Germany).…”

Section: Electrical Stimulationmentioning

confidence: 99%

Retinal ganglion cell (RGC) responses to different voltage stimulation parameters in rd1 mouse retina

Ryu

Kim

et al. 2010

2010 Annual International Conference of the IEEE Engineering in Medicine and Biology

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Retinal prostheses are being developed to restore vision for the blind with retinal diseases such as retinitis pigmentosa (RP) or age-related macular degeneration (AMD). Since neural prostheses depend upon electrical stimulation to control neural activity, optimal stimulation parameters for successful encoding of visual information are one of the most important requirements to enable visual perception. Therefore, in this paper, we focused on RGC responses to different stimulation parameters in degenerated retina. For this purpose, we used in vitro preparation of rd1 mice retina on microelectrode arrays. When the neural network of rd1 mice retinas is stimulated with voltage-controlled pulses, RGCs in degenerated retina also respond to voltage amplitude or voltage duration modulation as well in wild-type RGCs. But the temporal pattern of RGCs response is very different; in wild-type RGCs, single peak within 100 ms appears while in RGCs in degenerated retina multiple peaks (approximately 4 peaks) with approximately 10 Hz rhythm within 400 ms appear. The threshold charge densities for activation of RGCs in rd1 mouse retinas were on average 70.50 approximately 99.87 microC/cm(2) in the experiment of voltage amplitude modulation and 120.5 approxiamtely 170.6 microC/cm(2) in the experiment of voltage duration modulation.

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“…6) may be due to suppression by inhibitory presynaptic activity from the amacrine cell layer, which can last ϳ100 ms and impede responses to subsequent pulses at high pulse rates. [25][26][27] The frequency contents of natural scenes may become notably different from the two that we used in this study, and this may result in different optimal pulse rates, especially in the case of rapidly changing scenes. However, natural scenes are known to have 1/f 2 -type power spectra, 28 and thus significant information is contained in low-frequency bands.…”

Section: Discussionmentioning

confidence: 99%

“…The amplitude modulation range may be decreased in the case of multichannel stimulation-RGCs may be simultaneously activated by more than one stimulation electrode in close proximity. Different strategies for pulse parameter modulation such as frequency modulation 27 or precise control of short-latency responses 25 may be more adequate for multichannel stimulation. Our method based on spike train decoding can be readily applicable for the purpose of evaluating the effectiveness of different stimulation strategies in future studies.…”

Section: Discussionmentioning

confidence: 99%

Decoding of Temporal Visual Information from Electrically Evoked Retinal Ganglion Cell Activities in Photoreceptor-Degenerated Retinas

Ryu

Goo

et al. 2011

Invest. Ophthalmol. Vis. Sci.

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PURPOSE.To restore visual function via the prosthetic stimulation of retina, visual information must be properly represented in the electrically evoked neural activity of retinal ganglion cells (RGCs). In this study, the RGC responses in photoreceptor-degenerated retinas were shown to actually encode temporal information on visual input when they were stimulated by biphasic pulse trains with amplitude modulation. METHODS. Multiple RGC spike trains were recorded from rd1 mouse retinal patches mounted on planar microelectrode arrays while being stimulated by pulse trains with amplitudes modulated by the intensity variation of a natural scene. To reconstruct the time series of pulse train amplitudes from the evoked RGC activity, spike train decoding was performed. The accuracy of decoding-that is, the similarity between the original and decoded pulse amplitudes-was observed, to evaluate the appropriateness of the stimulation. RESULTS. The response strengths of the RGCs could be successfully modulated when the pulse amplitude was varied between 2 and 20 A. When the amplitude modulation range and pulse rates were determined elaborately, the temporal profile of the intensity could be successfully decoded from RGC spike trains, although abnormal oscillatory background rhythms (ϳ10 Hz) were consistently present in the rd1 spike activity. CONCLUSIONS. The results extend previous findings on the possibility of visual information encoding by electrical stimulation of normal retinas to stimulate degenerated retinas, in which neural activity is significantly altered. This supports the feasibility of encoding of temporal information by retinal prostheses. (Invest Ophthalmol Vis Sci. 2011;52:6271-6278 For the successful restoration of visual function, neural responses evoked by electrical stimulation should accurately represent spatiotemporal information on visual input. We have recently shown that in the normal retina, this is feasible through amplitude modulation of pulse trains when the parameters of stimulation are carefully selected.9,10 However, it has been recognized that RGC activity is significantly altered in the degenerated retina due to changes in synaptic properties 11,12 ; thus, abnormal rhythmic oscillation is present in both spontaneous and stimulated neural activity. Because this rhythmic oscillation does not originate from external visual inputs, it may disturb the representation and transmission of visual information by RGC activity in blind persons. Thus, visual information encoded by prosthetic electrical stimulation should be observed carefully in the degenerated retina.Quantitative investigation into information encoding by neuronal networks can be performed by spike train decoding, which consists of estimating (decoding) quantitative information encoded in neuronal activity. Typical applications include the study of fundamental visual information encoding characteristics of neuronal populations 13,14 and the control of brain-machine interfaces. 15 In the present study, we sought to determine whether it ...

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Electrically-evoked Neural Activities of rd1 Mice Retinal Ganglion Cells by Repetitive Pulse Stimulation

Cited by 15 publications

References 22 publications

Encoding visual information in retinal ganglion cells with prosthetic stimulation

Encoding visual information in retinal ganglion cells with prosthetic stimulation

Retinal ganglion cell (RGC) responses to different voltage stimulation parameters in rd1 mouse retina

Decoding of Temporal Visual Information from Electrically Evoked Retinal Ganglion Cell Activities in Photoreceptor-Degenerated Retinas

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