ABSTRACT
Long-term potentiation (LTP) is usually defined as a persistent increase in the synaptic efficacy of a monosynaptic neural pathway following a brief bout of high-frequency activity in the afferent fibers. This definition suffers from a number of ambiguities, but of particular relevance to this chapter is the problem that the phrase “increase in synaptic efficacy” does not specify the particular aspect of synaptic transmission that is responsible for the enhanced responding. This is an accurate reflection of our state of knowledge, however, as it is still a mystery as to whether LTP is due to larger excitatory postsynaptic potentials (EPSPs) at existing synapses, to EPSPs generated by newly formed synapses, to changes in the function of populations of synapses, to postsynaptic dendritic membrane changes, or to a combination of these events, each involving different cellular and kinetic properties.
