An integrated multichannel waveform generator for large-scale spatio-temporal stimulation of neural tissue

Abstract

We present an ASIC designed for electrical stimulation of neural tissue using multielectrode arrays. The ASIC is foreseen for applications in systems that require simultaneous stimulation and recording of signals from various types of neural tissue, both in vitro and in vivo. The developed ASIC comprises 64 independent stimulation channels, which are capable to generate arbitrarily defined bipolar current or voltage waveforms, controlled in real time with time resolution of 12.5 ls and amplitude resolution of 7 bits. The amplitude range of output signal can be scaled over a very wide range, which ensures compatibility with various electrode arrays of different size and geometry. Each channel is also equipped with a stimulation artifact suppressor controlled in real time, which reduces the dead time of the system after each stimulation pulse.

Focal Electrical Stimulation of Major Ganglion Cell Types in the Primate Retina for the Design of Visual Prostheses

“…A custom 64-channel stimulation and recording system with stimulation artifact suppression (Hottowy et al, 2008, 2012) was used to apply the electrical stimuli and record RGC responses to visual and electrical stimuli. The electrical stimuli consisted of charge-balanced triphasic current pulses with phase durations of either 50 or 100 μ s (150 or 300 μ s total pulse duration).…”

“…We probed the response properties of the five major ganglion cell types by simultaneous electrical recording and stimulation in isolated peripheral primate retina (31.4–65.9° temporal equivalent eccentricity) using multi-electrode arrays (Hottowy et al, 2008, 2012). The results reveal that it is possible to directly stimulate ON and OFF midget, ON and OFF parasol, and small bistratified RGCs using ~15 μ m diameter electrodes with current pulses in a safe charge density range.…”

High-Fidelity Reproduction of Spatiotemporal Visual Signals for Retinal Prosthesis

“…A custom 64-channel multichannel electrical stimulation system (Hottowy et al, 2008, 2012) was used in conjunction with electrode arrays to electrically stimulate and record. The arrays consisted of 61 approximately hexagonally packed indium tin oxide electrodes (60 µm spacing) on a glass substrate, electroplated with platinum black (Litke, 1998; Sekirnjak et al, 2006; Jepson et al, 2013).…”

“…Current pulses (150–300 µs total duration, triphasic, charge balanced [Hottowy et al, 2012; Jepson et al, 2013]) were injected with custom circuitry that permitted independent timing control on each electrode, as well as artifact reduction for recording and stimulating from the same electrode (Hottowy et al, 2008). Spikes recorded during electrical stimulation were analyzed with custom semiautomated procedures (Jepson et al, 2013).…”

Developments in neural vision technology

“…The stimulation/recording systems use 61 and 512-electrode MEAs (with 30 or 60 µm inter-electrode spacing) combined with a set of 64-channel "Stimchips" [20] and "Neuroplat" chips [21] developed by the Dabrowski group at the AGH University of Science and Technology in Krakow. The Stimchip, designed and applied to retinal prosthesis studies by Hottowy, includes 64 independent digital-to-analog converters for current or voltage stimulation, and circuitry for suppression of the electrical artifact.…”