28 01, 2010

Drawing a spark from the darkness, Frederik de Wilde EOD, artist

The modern world is dominated by electricity with an endless profusion of its technological applications. In medicine - and particularly in fields more or less connected to neuroscience - electricity is even more pervasive. Sensory transduction, the elaboration of nervous information, sensory reflexes and reactions of various complexity, the programming and execution of movements and of language production are all based to a large extent on a crowd of minute electric signals which, continuously flow along the nerve fibers of our brain circuits or the peripheral structures of nervous system.

There are many other life-electricity associations that come to mind, they are more tenuous but they are there, mostly fictional or anecdotal. When they clone an animal, they first take an egg cell and remove the original genes and substitute the DNA from the animal they want to clone. They then have to zap the cell with electricity which starts the first division. Michelangelo depicting the Creation of Adam had God giving Adam the spark of life. In Frankenstein, the monster is brought to life with a Spark from captured lightning. Our own nervous system uses an electrochemical signaling system, like an incessant 'electric storm'.

Living electric fish are capable of generating low-voltage discharges at all times and also produce a weak electromagnetic dipole field around their bodies as means of navigation, protection, and communication. If two fish of similar frequencies should happen to meet, one will shift its frequency, an act known as 'jamming avoidance response'. Scientists are still studying how this communication works. The electric organ contains electrically-excitable cells called 'electrocytes', acting as serial-connected batteries, like a car battery. The simultaneous firing of electrocytes results in electric organ discharges (EODs) which are emitted into the surrounding water.

You could say that every time they discharge -or zap- they sense and digitize their environment. They also sense pollution in the water and through technology we can make these electric discharges audible. Changes in the rate of pulsing can be used to identify the presence of certain chemicals in the water source. Currently these fishes are used in water refineries throughout the USA and Germany, as biomonitor, hence a means against bio terrorism. _ Frederik De Wilde, 2009

Bibliographical Reference: Piccolino, M. (2005) From an Ambiguous Torpedo to Animal and Physical Electricity, Audiological Medicine, Volume 3, Issue 2 June 2005, pages 124-132.