Fifty years of disconnexion syndromes and the Geschwind legacy

‘I read a book one day and my whole life was changed…I sat at the table turning the pages, my mind barely aware that I was reading, and my whole life was changing as I read the new words on each page.’ [From the opening paragraph of Orhan Pamuk’s Yeni Hayat (New Life), English translation by Guneli Gun].Had Pamuk’s protagonist been a behavioural neurologist, he might have chosen similar words to describe his first encounter with Norman Geschwind’s 1965 Disconnexion Syndromes in Animals and Man (Geschwind, 1965 a , b ). His experience would not have been unique. For the past half century, this two-part monograph has remained the most influential work ever published in the discipline that came to be known as behavioural neurology (Fig. 1). Figure 1 Norman Geschwind. (With kind permission of Claudia Geschwind).The monograph covered 116 pages of text, without a single table, figure or diagram. It offered an unprecedented synthesis of disparate neurological phenomena by translating them into the idiom of neuroanatomy at a particularly pivotal time in the history of neurological sciences. On the occasion of its 50th publication anniversary, the aim of this retrospective is to summarize for the general reader some of the main ideas in Geschwind’s monograph, highlight those that inspired further discovery, mention the few that require revision or amplification, and interpret the legacy of this paper from the vantage point of contemporary neurology. A comprehensive coverage of Disconnexion Syndromes, with a focus on broader themes related to the anatomy of cognition, appeared 10 years ago on the 40th publication anniversary of this work (Catani and ffytche, 2005).The Disconnexion Syndromes revived paradigmatic single case studies published by 19th century French and German neurologists, highlighted the functional rather than topographical subdivision of the cerebral cortex, espoused a hierarchical system …