The making of a memory mechanism

Long-Term Potentiation (LTP) is akind of synaptic plasticity that manycontemporary neuroscientists believe is acomponent in mechanisms of memory. This essaydescribes the discovery of LTP and thedevelopment of the LTP research program. Thestory begins in the 1950's with the discoveryof synaptic plasticity in the hippocampus (amedial temporal lobe structure now associatedwith memory), and it ends in 1973 with thepublication of three papers sketching thefuture course of the LTP research program. Themaking of LTP was a protracted affair.Hippocampal synaptic plasticity was initiallyencountered as an experimental tool, thenreported as a curiosity, and finally includedin the ontic store of the neurosciences. Earlyresearchers were not investigating thehippocampus in search of a memory mechanism;rather, they saw the hippocampus as a usefulexperimental model or as a structure implicatedin the etiology of epilepsy. The link betweenhippocampal synaptic plasticity and learning ormemory was a separate conceptual achievement.That link was formulated in at least threedifferent ways at different times: reductively(claiming that plasticity is identical tolearning), analogically (claiming thatplasticity is an example or model of learning),and mechanistically (claiming that plasticityis a component in learning or memorymechanisms). The hypothesized link withlearning or memory, coupled with developmentsin experimental techniques and preparations,shaped how researchers understood LTP itself.By 1973, the mechanistic formulation of thelink between LTP and memory provided anabstract framework around which findings frommultiple perspectives could be integrated intoa multifield research program.