Beyond Memory in H.M., The World’s Most Famous “Hippocampal Amnesic”

Abstract

Patient H.M. (Henry Moliason) suffered a wide range of cognitive deficits attributable to the damage to his hippocampal formation but not to his well-established deficits in the ability to recall newly encountered facts, events, names, and objects, which formed the basis for his early diagnosis as a “hippocampal amnesic.” Among Henry’s “non-memory” or cognitive deficits that this chapter reviews are his impaired ability to create new and grammatical sentence plans, to identify who-did-what-to-whom in novel sentences and to understand and read aloud novel sentences containing familiar words that he understood without difficulty in isolation, but not in novel sentence contexts such as metaphors. Also reviewed are his deficits in detecting novel forms concealed within complex visual arrays, in identifying anomalous objects in novel visual scenes, in detecting and describing what makes captioned cartoons funny, and in combining familiar concepts into new and useful ideas. The chapter concludes by relating Henry’s non-memory deficits to fundamental questions of this book, for example, What is the role of the hippocampal formation in human memory and cognition? And how does the hippocampal formation work?