Memory Development, Configurations, Conjunctions, and the Hippocampal Index

Abstract

When I began my career, I had no idea that much of it would center around the hippocampus. Here I discuss some of the history of how this happened. I briefly mention my early undergraduate life and the problems it posed for getting into graduate school. I describe the unique circumstances that led me to Allan Wagner's laboratory and changed my career trajectory. My path to the hippocampus began with a decision to study memory development. This led to a collaboration with Rob Sutherland that produced the configural theory of the hippocampus. The idea was that the hippocampus facilitated the construction of representations of the co-occurring stimulus elements currently experienced by the organism. Thus, if two elements, A and B, occurred together, a representation, AB, could be constructed that could be discriminated from its elements, A and B. This idea was partially correct, but we missed an important property of the hippocampal system that was recognized by O'Keefe and Nadel, 1978 that is, that the hippocampus is an unmotivated, rapid learning system. Randy O'Reilly and I addressed this issue in what we called conjunctive representation theory and put forth a detailed cortical-hippocampus computational theory to explain how this could work I later realized that our ideas were remarkably like Tim Teyler's indexing theory of how the hippocampal system supports memory. At a Park City meeting, a chance encounter with Tim (whom I had never met) resulted in the opportunity to write a paper with Tim updating the indexing theory, It is my favorite theoretical paper.