This refers to a theory of how neurons can learn to coordinate with each other over time to carry out new body functions. For example, as two neurons increasingly communicate with each other to carry out a new body function, the bond between them strengthens and facilitates the function. By the same token, when neurons stop interacting as often, the bond between them becomes weaker and affects body functions. The idea, which has been used to explain the flexible nature of the brain to learn new things, was proposed by Canadian psychologist Donald O. Hebb in his 1949 book The Organisation of Behaviour .
