Towards multifocal ultrasonic neural stimulation II: design considerations for an acoustic retinal prosthesis

Naor, Omer; Hertzberg, Y.; Zemel, Esther; Kimmel, Eitan; Shoham, Sharon

doi:10.1088/1741-2560/9/2/026006

Cited by 61 publications

(44 citation statements)

References 42 publications

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“…In practice, several protocols for neuromodulation imply that ultrasound is more efficient when delivered as a series of short (0.05–50 ms) applications [8], [9], [10], [11] than as a single long application with the same total exposure time (but see also reference 7). One group even found that ultrasound could either stimulate or inhibit neural activity depending on the duration of the application [11].…”

Section: Discussionmentioning

confidence: 99%

“…Although research on the effects of ultrasound on excitable tissue dates back to the 1920s [4], several recent results have revived interest in this phenomenon. Reversible changes in action potential frequency in response to low-intensity ultrasound (on the order of 0.1–10 W/cm 2 ) have been observed in vitro [5], [6] and in vivo [7], [8], [9], [10], [11]. In addition, transducer arrays that transmit ultrasound through the human skull have been implemented in high-intensity focused ultrasound surgery [12], [13], [14], [15], and it has been proposed that this technology could be adapted to deliver low-intensity ultrasound for the treatment of neurological disorders [5], [10].…”

Section: Introductionmentioning

confidence: 99%

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Dynamic Response of Model Lipid Membranes to Ultrasonic Radiation Force

et al. 2013

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Low-intensity ultrasound can modulate action potential firing in neurons in vitro and in vivo. It has been suggested that this effect is mediated by mechanical interactions of ultrasound with neural cell membranes. We investigated whether these proposed interactions could be reproduced for further study in a synthetic lipid bilayer system. We measured the response of protein-free model membranes to low-intensity ultrasound using electrophysiology and laser Doppler vibrometry. We find that ultrasonic radiation force causes oscillation and displacement of lipid membranes, resulting in small (<1%) changes in membrane area and capacitance. Under voltage-clamp, the changes in capacitance manifest as capacitive currents with an exponentially decaying sinusoidal time course. The membrane oscillation can be modeled as a fluid dynamic response to a step change in pressure caused by ultrasonic radiation force, which disrupts the balance of forces between bilayer tension and hydrostatic pressure. We also investigated the origin of the radiation force acting on the bilayer. Part of the radiation force results from the reflection of the ultrasound from the solution/air interface above the bilayer (an effect that is specific to our experimental configuration) but part appears to reflect a direct interaction of ultrasound with the bilayer, related to either acoustic streaming or scattering of sound by the bilayer. Based on these results, we conclude that synthetic lipid bilayers can be used to study the effects of ultrasound on cell membranes and membrane proteins.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Dynamic Response of Model Lipid Membranes to Ultrasonic Radiation Force

et al. 2013

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“…In a similar study using "focused" US that activated rabbit motor cortex measured by fMRI and behavior, the size of the acoustic focus was estimated to be 2.3 mm in diameter and 5.5 mm in length (Yoo et al, 2011). Finally, recent work has shown the feasibility of in vivo retinal stimulation (Naor et al, 2012) .…”

Section: Toward High-resolution Patterned Us Neurostimulationmentioning

confidence: 97%

Precise Neural Stimulation in the Retina Using Focused Ultrasound

et al. 2013

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Focused ultrasound is a promising noninvasive technology for neural stimulation. Here we use the isolated salamander retina to characterize the effect of ultrasound on an intact neural circuit and compared these effects with those of visual stimulation of the same retinal ganglion cells. Ultrasound stimuli at an acoustic frequency of 43 MHz and a focal spot diameter of 90 m delivered from a piezoelectric transducer evoked stable responses with a temporal precision equal to strong visual responses but with shorter latency. By presenting ultrasound and visual stimulation together, we found that ultrasonic stimulation rapidly modulated visual sensitivity but did not change visual temporal filtering. By combining pharmacology with ultrasound stimulation, we found that ultrasound did not directly activate retinal ganglion cells but did in part activate interneurons beyond photoreceptors. These results suggest that, under conditions of strong localized stimulation, timing variability is largely influenced by cells beyond photoreceptors. We conclude that ultrasonic stimulation is an effective and spatiotemporally precise method to activate the retina. Because the retina is the most accessible part of the CNS in vivo, ultrasonic stimulation may have diagnostic potential to probe remaining retinal function in cases of photoreceptor degeneration, and therapeutic potential for use in a retinal prosthesis. In addition, because of its noninvasive properties and spatiotemporal resolution, ultrasound neurostimulation promises to be a useful tool to understand dynamic activity in pharmacologically defined neural pathways in the retina.

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“…Experiments have indicated that on-off modulated ultrasound waves can elicit action potentials from retinal and brain cells (Tufail et al, 2010; Naor et al, 2012; Menz et al, 2013). However, very little is understood about how mechanical deformations (typically in the cell membrane) affect ion channels, membrane capacitances and neurons—although proposed mechanisms have included cavitation and thermal effects.…”

Section: Neuromodulation Modalitiesmentioning

confidence: 99%

Neuromodulation: present and emerging methods

et al. 2014

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Neuromodulation has wide ranging potential applications in replacing impaired neural function (prosthetics), as a novel form of medical treatment (therapy), and as a tool for investigating neurons and neural function (research). Voltage and current controlled electrical neural stimulation (ENS) are methods that have already been widely applied in both neuroscience and clinical practice for neuroprosthetics. However, there are numerous alternative methods of stimulating or inhibiting neurons. This paper reviews the state-of-the-art in ENS as well as alternative neuromodulation techniques—presenting the operational concepts, technical implementation and limitations—in order to inform system design choices.

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Towards multifocal ultrasonic neural stimulation II: design considerations for an acoustic retinal prosthesis

Cited by 61 publications

References 42 publications

Dynamic Response of Model Lipid Membranes to Ultrasonic Radiation Force

Dynamic Response of Model Lipid Membranes to Ultrasonic Radiation Force

Precise Neural Stimulation in the Retina Using Focused Ultrasound

Neuromodulation: present and emerging methods

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