"The surgeon claimed that the destruction was precise, but the autopsy actually determined that damage was much more widespread than expected." This is flat wr

"The surgeon claimed that the destruction was precise, but the autopsy actually determined that damage was much more widespread than expected." This is flat wrong. Based on structural neuroimaging evidence, Corkin et al. (1997) showed that HM's resection was less extensive than Scoville's notes suggested, not more extensive. The more recent post-mortem analysis of HM's brain (Annese et al., 2014) concurs, and in fact gives an even more conservative estimate of the resection. As a researcher who studies memory and works with severely amnesic patients, I think that it's important to point out that the precision of HM's lesion was unique in our field because every other bilateral hippocampal amnesic patient has a naturally-occurring lesion. Etiologies vary (herpes simplex encephalitis, anoxia, and, historically, Korsakoff's), but common to each etiology is the potential for widespread damage beyond the hippocampus and medial temporal lobe (MTL). Given that HM's surgery predated sophisticated neuroimaging methods, his case provided researchers of the era the very best possibility of isolating the cognitive processes that depended on the MTL. There have been many methodological and theoretical improvements over the intervening decades, but the work that Brenda Milner, Sue Corkin, and many others carried out with HM was seminal for the field. Annese, J., Schenker-Ahmed, N. M., Bartsch, H., Maechler, P., Sheh, C., Thomas, N., … Corkin, S. (2014). Postmortem examination of patient H.M.’s brain based on histological sectioning and digital 3D reconstruction. Nature Communications, 5, 3122. doi:10.1038/ncomms4122 Corkin, S., Amaral, D. G., Gonzalez, R. G., Johnson, K. A., & Hyman, B. T. (1997). H.M.’s medial temporal lobe lesion: findings from magnetic resonance imaging. J. Neurosci., 17, 3964–3979.