Narrative construction is intact in episodic amnesia

Abstract

Autobiographical remembering and future imagining overlap in their underlying psychological and neurological mechanisms. The hippocampus and surrounding regions within the medial temporal lobes (MTL), known for their role in forming and maintaining autobiographical episodic memories, are also thought to play an essential role in fictitious and future constructions. Amnesic individuals with bilateral hippocampal damage cannot reconstruct their past personal experiences and also have severe deficits in the ability to construct coherent fictitious or future narratives. However, it is not known whether this impairment reflects a failure to generate details from autobiographical episodic memory to populate personal narratives or an inability to bind such details into coherent narratives. We show that four individuals with hippocampal damage and episodic amnesia can construct narratives when the relevant details of the story are provided in a picture book and that their narratives maintain overall coherence on several measures. These findings indicate that individuals with hippocampal damage can bind details into coherent narratives when details are available to them. We conclude that the hippocampal system instead likely plays a role in the generation of details from which narratives are constructed.