Per Andersen. 12 January 1930—17 February 2020

Abstract

Per Andersen was one of the leading neuroscientists of the second half of the twentieth century. He spent his entire career at the University of Oslo, apart from an exceptionally productive postdoctoral period with Sir John Eccles FRS at the Australian National University in Canberra between 1961 and 1963. As a PhD student he laid the foundation of field potential analysis, which allowed synaptic function in laminated cortical structures such as the hippocampus to be followed for long periods in intact animals, an essential technical prerequisite for the study of the synaptic basis of memory. In Canberra he identified the neurons responsible for feed-back inhibition in the hippocampus and feed-forward inhibition in the cerebellum, the first inhibitory neurons to be functionally identified in the mammalian brain. Per's Canberra achievements catapulted him to superstar status, and enabled him on his return to Oslo in 1963 to establish a laboratory that played a major role over the following decades in characterizing the functional properties of hippocampal synapses. From his laboratory emerged a string of significant advances, including the discovery of long-term potentiation, a form of synaptic plasticity widely believed to support learning and memory, and the introduction of the transverse hippocampal slice, which rapidly became the dominant preparation for investigating the properties of hippocampal neurons. Young researchers, many from the USA and Canada, flocked to his laboratory for postdoctoral training, adding to the steady stream of Norwegian doctoral students, two of whom went on to win the Nobel Prize. Per was also committed to the importance of communicating scientific advances to the general public, and contributed prolifically over the years to the Norwegian media, commentating on advances in neuroscience and their relevance to neurological disorders.