Community Research and Development Information Service - CORDIS

New amplifiers improve electrophysiological monitoring techniques

Using amplifier technology, electrophysiological measurements can be amplified to provide signals from low-cost amplifiers with constantly improving technical characteristics.
New amplifiers improve electrophysiological monitoring techniques
Electrophysiological measurements are obtained from potential differences in cells. Cells, which make up living tissue, contain intra-cellular fluids, which have different chemical concentrations compared to the extra-cellular fluids. Since the cell membrane is semi-permeable, a potential difference is generated across it. When a cell is stimulated, a sudden change of chemical concentration occurs across its membrane, which leads to a change in the potential across the membrane. This change can be detected, providing an electrophysiological recording.

The changes in the electrical charges of the tissue cells are sensed through electrodes, which are placed inside (intra-cellular) or near (extracellular) a cell of interest. However the electrical signal that the electrode senses is extremely small and needs to be amplified. An amplifier measures current or voltage and passes that measurement on for recording and analysis. The technical efficiency of the amplifier is of primary importance since the electrophysiological measurements must be accurate, stable, low in noise and reliable.

New amplifiers were developed to amplify electrical signals from live animals nerves (in vivo) or from dissected parts of the nervous system that are still alive (in vitro). These amplifiers are as effective as the best existing commercial devices but they are less expensive and the background noise is extremely low. The amplification gain is adjustable in the range from 1000 to 500 000 and it is available in three different versions. These are, a standard version, which is multichannel (4-6 channels), a simplified version suitable for educational purposes and a conditioner version able to be used directly with a data processing computer.

Electrophysiological recordings such as electrocardiograms, myograms, encephalograms and occulograms, require measurements of small biological potentials. The main application of these amplifiers is the recording of data from electrodes in electrophysiology in a reliable, efficient and cost-effective manner.

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Record Number: 81039 / Last updated on: 2005-09-18
Domain: Biology, Medicine