ABSTRACT
Edgar Douglas Adrian was a prolific researcher who was the first to record electrical activity from single axons that established frequency coding in an all-or-nothing manner as the means by which neurons transmit information. Towards the end of his career, Adrian advanced our understanding of smell, especially by identifying the contributions of sensory nose receptors in stimulating the mitral units of the olfactory bulb. Adrian and Yngve Zotterman extended their single unit recordings to other types of cell including sensory neurons transmitting touch information from skin of the cat paw, along with other receptors involved in pain. When Adrian used an oscilloscope to visualise the impulses from the single axon, they appeared as small rapidly occurring spikes on the screen. As Adrian stretched the spindle, the number of spikes per second increased, with the number of impulses proportional to the strength of the sensory stimulus.
