Coding and representation: Searching for a home in the brain

1'11~ idea that mental experience may leave residue in the soul, or mind, that allows later remembering of the experience is as old as recorded history, and probably older. The idea that this residue is physical, somewhere in the brain, 8% more recent, having been first proposed by Robert Hooke (1627-1703) who ~hought that memory is 'as much an Organ as the Eye, Ear, or the Nose', and 1Iii11 it has'its situation somewhere near the Place where Nerves from the other \lbnses concur and meet' (Young 1965, p. 287). The existence of this 'residue' with a remarkable staying power is now taken lor granted, but much about it has remained baffling. How is it formed? What I\ its nature? What kind of thing, or entity or stuff is it? What is the relationship Iwtween the experience and its residue? What is the relationship between thc residue and remembering that it enables? Where does the residue reside? I)oes every experience leave a residue? If not, then what determines which ones do and which ones do not? If yes, what kind of a place is it that can 'hold' .In individual's untold experiences? Does the residue last forever? (Not many \cicntists believe this, but I think that some do.) Does it last at least as long as the individual is alive? These and related questions have been raised and ilcbated, sometimes hotly debated, throughout the human intellectual history. At the present time, n o one knows what the answers are, although we have ~~ndoubtedly made progress in getting a better grip on the questions. The terms that have been used to refer to the memorially relevant components o f the after-effects of experience have varied with the fashions of the times, the .~ccumulated pertinent knowledge already available, and even the languages. ~ n d dialects spoken by those who have thought deeply about the matter. A frequently used term is 'representation', another is 'coding'-as in the title of this section of the book. Other well-known terms are 'engram', 'memory ~rnage' and 'memory trace'. Each has its own connotations that vary from context to context and even from writer to writer, although the concept lying behind all these terms has been and continues to be relatively unambiguous.