Experience-near but not experience-far autobiographical facts depend on the medial temporal lobe for retrieval: Evidence from amnesia

This paper addresses the idea that there may be two types of autobiographical facts with distinct cognitive and neural mechanisms: “Experience-near” autobiographical facts, which contain spatiotemporal content derived from personal experience and thus depend on the medial temporal lobe (MTL) for retrieval, and “experience-far” autobiographical facts, which are abstract memories and thus rely on neocortical brain regions involved in retrieval of general semantic memory. To investigate this conceptual model of autobiographical fact knowledge, we analyzed the nature of autobiographical facts that were generated by 8 individuals with MTL amnesia and 12 control participants in a recent study of identity and memory [Grilli, M.D., & Verfaellie, M. (2015). Supporting the self-concept with memory: insight from amnesia. Social Cognitive and Affective Neuroscience, 10, 1684-1692]. Results revealed that MTL amnesic participants generated fewer experience-near autobiographical facts than controls. Experience-far autobiographical fact generation was not impaired in amnesic participants with damage restricted to the MTL, but there was preliminary evidence to suggest that it may be impaired in amnesic participants with damage to the MTL and anterior lateral temporal lobe. These results support a cognitive and neural distinction between experience-near and experience-far autobiographical facts and have implications for understanding the contribution of autobiographical fact knowledge to self-related cognition.