A new transparent multi-unit recording array system fabricated by in-house laboratory technology

A new recording array system has been developed to record multi-unit activity in rabbit retina. The array consists of individually laid down layers of carbon fiber or tungsten microelectrodes whose center-center spacing can be made less than 100 mum. The array and associated electronics can be constructed by technology typically found in most electrophysiology laboratories. The array is mostly transparent, so that visual stimuli and microscopic examination can take place through it. The array can be manipulated much like a single electrode, and thus can be used to record from multiple tissue sites. Arrays as large as 32 elements have been used, with success rates of about 50% per electrode, with some electrodes picking up more than one cell. Stable recordings have been held for up to 6 h from groups of ganglion cells in an isolated eyecup preparation. These multi-electrode arrays have been used repeatedly in experiments for several months without any obvious degradation in recording quality. Although the arrays are hand-made, their layered method of assembly allows as many as 32 elements to be assembled. (C) 2003 Elsevier Science Ltd. All rights reserved.