Three decades and 6,000 papers since the term was first coined, scientists are still debating the mechanisms of long-term potentiation (LTP).1 Defined in 1973 as an increase in synaptic strength following experimentally induced high-frequency stimulation,2 LTP has been consistently controversial. Now at last, "There is a consensus beginning to emerge," says Columbia University Nobel laureate, Eric Kandel, as years of research have begun to make sense of what once seemed irreconcilable contradictions. An almost decade-long argument over whether LTP should be considered presynaptic or postsynaptic now appears settled, allowing researchers to pursue finer details.
Among neuroscientists, the "LTP equals learning" definition has given way to a broader understanding of the process as a family of brain mechanisms involved in associating stimuli. "I'm of the camp, and I've changed a lot over the years, that LTP and LTD [long-term depression, the downregulated counterpart] are basically core mechanisms, almost as fundamental as ...
