Abstract
Abstract: :
Purpose: Recording from multiple retinal gangion cells simultaneously in ganglion cell side up configuration. Ganglion cell side down configurations tend to result in shorter recording times and compromised responsivity. Another goal was to be able to move the recording array to a well responding area of the retina. Methods: Use of a new multiunit array. A new recording array system has been developed to record multiunit activity in rabbit retina. The array consists of individually laid down layers of tungsten or carbon fiber electrodes whose center spacing can be made less than 100 microns. The array is manipulatable much like a single electrode, and thus can be used to record from multiple sites in a normal superfused eyecup preparation.Results: Stable recordings have been made from 10 or more cells for 4-6 hours. Arrays as large as 32 elements have been used, with success rates of about 50% per electrode, with many electrodes picking up more than one cell. This is primarily because the array elements are made like normal extracellular electrodes. The array has been used to monitor stimulus-dependent firing in ganglion cells, particularly directionally selective ganglion cells. Results have been similar to those obtained with dual, individually manipulated electrodes in these cells, specifically, correlated firing in directionally selective ganglion cells occurs primarily for stimuli that are spatially extended and moving. Conclusion: Recordings extend previous dual recording experiments on synchronous firing in directionally selective and other ganglion cells. Although the arrays are hand-made, their layered method of assembly may soon allow more automated manufacturing techniques.
Keywords: 394 electrophysiology: non-clinical • 415 ganglion cells • 559 retinal connections, networks, circuitry