Long term potentiation (LTP) is a form of synaptic plasticity which can be observed in neurons, and was first presented by Norwegian physiologist Terje Lømø in 1966. LTP is believed to be a process underlying memory, and is characterized by a measurable persistent increase in synaptic transmission between nerve cells.
Source: Lømo, Terje (1966). “Frequency potentiation of excitatory synaptic activity in the dentate area of the hippocampal formation”. Acta Physiologica Scandinavica. 68 (Suppl 277): 128.