ABSTRACT
There is an interesting way in which thinking about the physiological and cellular mechanics of learning and memory formation has become divorced from knowledge about the processes of remembering and of memory systems derived from neuropsychology. The conventional physiological wisdom, derived from the earlier molluscan studies of Alkon (1987) and Kandel (e.g., Hawkins, Kandel, & Siegelbaum, 1993) and from work on hippocampal long-term potentiation (LTP; McNaughton, 1993), is that memory formation is essentially a Hebbian process, although variants on the Hebb rules, such as homosynaptic and anti-Hebbian pairings, are permitted (Singer, 1990). Hebbian memory depends on the alteration of synaptic weights within, at best, small ensembles of neurons, so as to strengthen or weaken connections, and it is this type of memory that has been extensively modeled by connectionist theoreticians (Churchland & Sejnowski, 1992). The implication of such models for the cellular mechanics of memory formation is that a linear sequence of biochemical events, culminating in altered synaptic morphology, occurs within the neurons of the ensemble, and that these events form the cellular analogues of short- and long-term memory, although at least since the classic paper of McGaugh (1964), it has been recognized that the “phases” of memory may run in parallel, rather than sequentially.
