Visual Electrophysiology on a Tight Budget: Penetrating Microelectrode Arrays and Visual Stimulation

Abstract

It is desirable to make recordings from sensory ganglia such as the retina with penetrating microelectrode arrays that can reach neurons below surface of the tissue. It is also desirable to use a high frame rate, small screen visual stimulator to investigate phenomena such as correlated firing without temporal artefacts from slow and non-uniform video displays. We have developed a recording system based on inexpensive in house laboratory technology to accomplish both objectives. The recording array consists of insulated 12-25 micrometer tungsten or steel wires whose positions are set by the use of very fine capillary tubing. Inter-electrode spacing of 50 micrometers is achievable with the array, which is transparent except for the electrode wires. The visual stimulator is an LED matrix driven by an Arduino mega with a drive cycle of 490 Hz.