1st Baron Edgar Douglas Adrian was an English electro-physiologist who shared the 1932 Nobel prize in physiology with Sir Charles Sherrington for his work on the functions of neurons. He was also responsible for the development of electroencephalography (EEG) to measure brain activity, an invaluable tool that has helped numerous doctors diagnose brain tumours and epilepsy.
Adrian was born on the 30th November 1889 in London. Adrian went to Trinity College, after winning a scholarship to study at Cambridge, where he studied physiology and natural sciences. In 1913 he was elected to a fellowship of Trinity college for his investigation into the ‘all or nothing principle’. The principle that the strength of which a nerve or fibre of muscle responds to a stimulus does not correlate to the strength of the original stimulus. It is the idea that the nerve or muscle fibre has a threshold value and if the stimulus exceeds this value a response will occur, below this and there will be no response.
During the war Adrian completed his medicine degree in London and treated patients from the armed services, using the unfortunate opportunity to document as much about the physical sensation and interpretation of pain as possible.
Post war, Adrian returned to Cambridge in 1919 where he dedicated much of his time to teaching and furthering his understanding of the functions of nerve cells. In 1925 he began his investigations into the sense organs and with the help of electrical implementations he had designed, was able to detect the slightest of nerve impulses. Using a cathode ray tube, capillary electrometer and thermionic valve he could amplify the responses seen by 5,000 times. He successfully demonstrated the use of his device on a single end organ in the muscle of a frog.
Adrian discovered that by stimulating the matching single nerve, regular impulses were recorded but the frequency could be altered. In 1928 he was able to publish his conclusion that a stimulus of a constant intensity applied to the skin, immediately excites the end organ, but that this excitation progressively decreases. At the same time sensory impulses of constant intensity pass along the nerve and whilst at first are frequent they gradually decrease and in doing so the sensation in the brain dulls as well.
Later Adrian expanded his study into electrical impulses caused by stimuli linked to pain and found the nerve fibres excitable by pain stimuli don’t regularly pass further than the optic thalamus. He did however note that all other sensory impulses can be found in the cortex and that regions of the cortex are devoted to particular organ ends. His example being that in a man the sensory area of the cerebral cortex devoted to the face and hand is relatively large in comparison to other areas of the body.
In 1929 Adrian used his electroencephalography, to study the sense of smell and the electrical activity of the brain. He and Hans Berger noticed variations and abnormalities of waves amongst individuals and this began opening up new methods of investigation into the study of epilepsy.