William Grey Walter: Encyclopedia II - William Grey Walter - Walter's work on brain waves

William Grey Walter - Walter's work on brain waves

As a young man Walter was greatly influenced by the work of the famous Russian physiologist Ivan Pavlov. He visited the lab of Hans Berger, who invented the electroencephalograph, or EEG machine, for measuring electrical activity in the brain. Walter produced his own versions of Berger's machine with improved capabilities, which allowed it to detect a variety of brain wave types ranging from the high speed alpha waves to the slow delta waves observed during sleep.

In the 1930s Walter made a number of discoveries using his EEG machines at Burden Neurological Institute in Bristol. He was the first to locate correctly the source of alpha waves by triangulation within the occipital lobe of the brain and demonstrated the use of delta waves to locate brain tumours or lesions responsible for epilepsy. He developed the first brain topography machine based on EEG, using on an array of spiral-scan CRTs connected to high-gain amplifiers.

During the Second World War he worked on scanning radar technology and guided missiles, which may have influenced his subsequent alpha wave scanning hypothesis of brain activity.

In the 1960s Walter also went on to discover the contingent negative variation (CNV) effect (or readiness potential) whereby a negative spike of electrical activity appears in the brain half a second prior to a person being consciously aware of movements that he is about to make. Intriguingly, this effect brings into question the very notion of consciousness or free will, and should be considered as part of a person's overall reaction time to events.

Adapted from the Wikipedia article "Walter's work on brain waves", under the G.N U Free Docmentation License. Please also see http://en.wikipedia.org/wiki