Detection of retinal signals using position sensitive microelectrode arrays

Mathieson, K and Cunningham, W and Marchal, J and Melone, J and Horn, M and Gunning, D and Tang, R and Wilkinson, C and O'Shea, V and Smith, KM and Litke, A and Chichilnisky, E and Rahman, M (2003) Detection of retinal signals using position sensitive microelectrode arrays. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 513 (1-2). pp. 51-56. ISSN 0168-9002 (

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To understand the neural code, that the retina uses to communicate the visual scene to the brain, large-area microelectrode arrays are needed to record retinal signals simultaneously from many recording sites. This will give a valuable insight into how large biological neural networks (such as the brain) process information, and may also be important in the development of a retinal prosthesis as a potential cure for some forms of blindness. We have used the transparent conductor indium tin oxide to fabricated electrode arrays with approximately 500 electrodes spaced at 60 μm. The fabrication procedures include photolithography, electron-beam lithography, chemical etching and reactive-ion etching. These arrays have been tested electrically using impedance measurements over the range of frequencies important when recording extracellular action potentials (0.1-100kHz). The data has been compared to a circuit model of the electrode/electrolyte interface. One type of array (512 electrodes) behaves as theory would dictate and exhibits an impedance of 200 kΩ at 1kHz. The other array (519 electrodes) has an impedance of 350 kΩ at this frequency, which is higher than predicted by the models. This can perhaps be attributed to the difference in fabrication techniques. The 512-electrode array has been coupled to low-noise amplification circuitry and has recorded signals from a variety of retinal tissues. Example in vitro recordings are shown here.


Mathieson, K ORCID logoORCID:, Cunningham, W, Marchal, J, Melone, J, Horn, M, Gunning, D ORCID logoORCID:, Tang, R, Wilkinson, C, O'Shea, V, Smith, KM, Litke, A, Chichilnisky, E and Rahman, M;