Functional Connectivity Map of Retinal Ganglion Cells for Retinal Prosthesis

Abstract

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). Among the many issues for prosthesis development, stimulation encoding strategy is one of the most essential electrophysiological issues. The more we understand the retinal circuitry how it encodes and processes visual information, the greater it could help decide stimulation encoding strategy for retinal prosthesis. Therefore, we examined how retinal ganglion cells (RGCs) in in-vitro retinal preparation act together to encode a visual scene with multielectrode array (MEA). Simultaneous recording of many RGCs with MEA showed that nearby neurons often fired synchronously, with spike delays mostly within 1 ms range. This synchronized firing -narrow correlation -was blocked by gap junction blocker, heptanol, but not by glutamatergic synapse blocker, kynurenic acid. By tracking down all the RGC pairs which showed narrow correlation, we could harvest 40 functional connectivity maps of RGCs which showed the cell cluster firing together. W e suggest that finding functional connectivity map would be useful in stimulation encoding strategy for the retinal prosthesis since stimulating the cluster of RGCs would be more efficient than separately stimulating each individual RGC.

Spike-triggered average electrical stimuli as input filters for bionic vision—a perspective

“…Thus, the sequence of subthreshold pulses can be considered to be a suprathreshold stimulus. We are not the first to make this observation that spreading stimulation out over extended time can reduce the stimulus amplitude necessary to elicit a response (Sekirnjak et al 2006;Boinagrov et al 2010;Johnson et al 2004;Eickenscheidt et al 2012;Ye et al 2008;Grumet et al 2000;Goo et al 2011;Samba et al 2015). In fact, this relationship underlies the classic strength-duration curve.…”

Effect of Stimulus Waveform of Biphasic Current Pulse on Retinal Ganglion Cell Responses in Retinal Degeneration (rd1) mice

“…Due to the advantage of large number of recording and stimulation channels, multielectrode array (MEA) electrodes have been used to record from a wide variety of neuronal preparations including the isolated retina [ 7 , 8 , 9 , 10 , 11 , 12 , 13 ].…”

Mapping Functional Connectivity between Neuronal Ensembles with Larval Zebrafish Transgenic for a Ratiometric Calcium Indicator

“…The control of this process is thought to be the basis of cognition, and irregularities are thought to be at the core of many mental disorders, substance abuse, and seizures. Functional connectivity, an important component of this problem, has been studied at the cognitive level using fMRI (Logothetis, 2003 ; Zhou et al, 2009 ), MEG (Owen et al, 2009 ; Stam, 2009 ; Babajani-Feremi and Soltanian-Zadeh, 2010 ), and EEG (Cantero et al, 2009 ; Carbonell et al, 2009 ; de Haan et al, 2009 ), and at the microcircuit level using multi-electrode arrays (Chiu and Weliky, 2002 ; Pillow et al, 2008 ; Ye et al, 2008 ; Field et al, 2010 ) and optical imaging techniques (Cacciatore et al, 1999 ; Taylor et al, 2003 ). While these approaches have yielded important insights into brain function, they have typically either addressed global pathways or microcircuitry without linking the two together.…”