A neural interface for a cortical vision prosthesis

Abstract

The development of a cortically based vision prosthesis has been hampered by a lack of basic experiments on phosphene psychophysics. This basic research has been hampered by the lack of a means to safely stimulate large numbers of cortical neurons. Recently, a number of laboratories have developed arrays of silicon microelectrodes that could enable such basic studies on phosphene psychophysics. This paper describes one such array, the Utah electrode array, and summarizes neurosurgical, physiological and histological experiments that suggest that such an array could be implanted safely in visual cortex. We also summarize a series of chronic behavioral experiments that show that modest levels of electrical currents passed into cortex via this array can evoke sensory percepts. Pending the successful outcome of biocompatibility studies using such arrays, high count arrays of penetrating microelectrodes similar to this design could provide a useful tool for studies of the psychophysics of phosphene perception in human volunteers. Such studies could provide a proof-of-concept for cortically based artificial vision.

Correlated variability modifies working memory fidelity in primate prefrontal neuronal ensembles

“…As in refs. 27 and 45, we chronically implanted a 10 × 10, 1.5-mm microelectrode array (Blackrock Microsystems LLC) (52,53) in each monkey's left LPFC-anterior to the knee of the arcuate sulcus and caudal to the posterior end of the principal sulcus (area 8a) (Fig. 1B).…”

Demonstration of artificial visual percepts generated through thalamic microstimulation

“…Research efforts in visual prostheses can be split into two broad approaches: those in which healthy retinal neurons are stimulated (1,2), and those in which visual cortical neurons are stimulated (3)(4)(5). Retinal approaches have enjoyed some success, but have been hampered in part because of retinal fragility, which complicates implantation, and retinal architecture, which complicates electrical stimulation.…”

Implanted intracortical electrodes as chronic neural interfaces to the central nervous system

“…The sites are then metalized using a lift off procedure. 6 Iridium is typically used for the electrodes (due to their ability to be electrochemically activated to act as a stimulation site [44,45] and carry a lower impedance 7 ) and gold is typically used for the bond pads. See Figure 5C.…”

“…House et al first began human trials of single-channel cochlear implants in the early 1960's [3,4] and are often cited as implementing one of the first neuroprosthetics. Since then, numerous other neuroprostheses have been created for restoring or aiding motor function [5], vision [6], and pro-actively treating epileptic seizures [7] or the effects of Parkinson's disease [8]. While all of these are promising and worthwhile, here an emphasis is placed on neural interfaces with the intention of controlling a robotic prosthetic (as in the case of an amputee).…”