Raymond Michael Gaze. 22 June 1927—11 September 2012

Abstract Mike Gaze devoted his career to understanding how nerves form precise connections. His experiments focused on the nerves connecting the eye to the brain in frogs and fish. Mike pioneered the use of electrophysiological recording in investigating how the nervous system develops. This technique enabled him a greater degree of anatomical precision than had previously been possible. The dominant theory on how nerve connections are formed was Sperry's chemoaffinity theory (Roger Wolcott Sperry (ForMemRS 1976)), based on the results of regeneration experiments. Mike repeated Sperry's experiments using his better technique. He then extended Sperry's work: first, to the development of retinotectal connections following various surgical operations on the embryonic eye; second, to regeneration following surgical reductions in the size of the tectum or retina; and third, to normal development. In each case he showed, for the first time, that connections are plastic. Even during normal development, retinal fibres are continually changing their connections. This was a radical finding. It implied, contrary to Sperry's theory, that retinal fibres interact with each other in forming tectal connections. Mike called this dynamic process systems matching. Mike then investigated how retinal fibres behave before they reach the brain. In further original work, Mike, with former student Mike Keating, showed, contrary to the prevailing view, that functional value can affect the development of specific nerve connections. In the 30 years since Mike retired there has been much work on the molecular bases underlying nerve connections. These have confirmed Mike's original findings and ideas.