Like learning, LTP can be defined as a long-lasting change in output in response to a transient input. The persistence of this effect has been demonstrated to extend many hours in vitro and several weeks in vivo. We do not know how LTP relates to memory and the entire ninth chapter of the book will be devoted to the evidence for and against the hypothesis that hippocam-pal LTP is involved in memory. Regardless, it is the best-understood example of long-lasting synaptic plasticity in the mammalian CNS, and it is a model for how long-lasting memory-associated changes are likely to occur in the CNS. One premise of this book is that understanding LTP will yield valid insights into the mechanisms of plasticity that underlie learning and memory in the brain. The bona fide changes in neuronal connections that occur in vivo may or may not be identical to LTP as it is presently studied in the laboratory, but this does not diminish its utility as a cellular model system for studying lasting neuronal change in the mammalian CNS.
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Complexities of LTP J. David Sweatt, Acrylic on canvas, 2002
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