Reply to Maguire and Hassabis: Autobiographical memory and future imagining

The role of the hippocampus in recollecting past events and imagining future events is of some theoretical interest, but experimental work on this issue is difficult because it depends on analysis of spoken narrative and the availability of appropriate patients. Because lateral temporal and frontal damage can markedly impair the ability to produce well-formed autobiographical memories about specific events (1), it is especially useful to obtain quantitative MRI data about these regions (and medial temporal lobe structures). This information was not available for the four patients with limbic encephalitis who had difficulty imagining future events (2), but descriptions of three of them in other reports, as cited (3), suggested to us that they have abnormalities outside the hippocampus. Patient P02 has “some generalized atrophy” and 4 mo after treatment was described as having “blank spells thought to represent seizures” (see ref. 5 in Supporting Information of ref. 2). P03 was described at the 27-mo follow-up as having persisting personality change and was taking antiepileptic medication. The IQ of P04 fell from 112 to 99 (4) and was at this level when he participated in tests of imagining (2).