Height: 12 cm
Width: 25 cm
Depth :19 cm
Manufacturer: MetaMetrics Corporation
Model: MetaMembron 77
Date:c1980
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Dr. Richard Fraser, Director of the Maude Abbott Medical Museum, provides a brief description of the function and/or use of the equipment.
The MetaMembron 77 is an analog computer made up of 264 transistors and 18 operational amplifiers that simulates in real-time the electrical activity of a neuronal axon. It features several outputs. One gives the voltage across the membrane of the cell; others show, for example, the sodium and potassium currents flowing across the cell membrane. Controls for "poisoning" the membrane with tetrodotoxin (TTX) and/or tetraethylammonium (TEA) are also present.
Circuit boards inside the device.
The device was purchased by Dr Michael Mackey and used by him, Dr. Ellis Cooper, and Dr. Mladen Glavinovic for electrophysiology teaching and by Dr. Michael Mackey and Dr. Michael Guevara for research. It was called the “squid box” because it is an analog simulation of the electrical behavior of one square centimeter of squid axon membrane.
An oscilloscope screen image taken of one experiment shows a periodic rhythm, each cycle of which consists of several small sine-wave-looking cycles towards the bottom of the trace. These slowly increase in amplitude until an isolated action potential (the sharp high-amplitude spike) is generated, after which the next cycle of the “mixed-mode oscillation” begins.
Reference: Guevara, M.R., “Displaced reinjection attractors in an electronic analogue of the membrane of the squid giant axon”. In G. Baier & M. Klein (Eds.), “A Chaotic Hierarchy”, World Scientific, 1991, pgs. 153-164.