Episodic Memory and Episodic Future ThinkingudImpairments in High-Functioning Autism SpectrumudDisorder: An Underlying Difficulty With SceneudConstruction or Self-Projection?

摘要

Objective: There appears to be a common network of brain regions that underlie the ability to recalludpast personal experiences (episodic memory) and the ability to imagine possible future personaludexperiences (episodic future thinking). At the cognitive level, these abilities are thought to rely onud“scene construction” (the ability to bind together multimodal elements of a scene in mind—uddependent on hippocampal functioning) and temporal “self-projection” (the ability to mentallyudproject oneself through time—dependent on prefrontal cortex functioning). Although autism spectrumuddisorder (ASD) is characterized by diminished episodic memory, it is unclear whether episodicudfuture thinking is correspondingly impaired. Moreover, the underlying basis of such impairmentsud(difficulties with scene construction, self-projection, or both) is yet to be established. The currentudstudy therefore aimed to elucidate these issues. Method: Twenty-seven intellectually highfunctioningudadults with ASD and 29 age- and IQ-matched neurotypical comparison adults wereudasked to describe (a) imagined atemporal, non-self-relevant fictitious scenes (assessing sceneudconstruction), (b) imagined plausible self-relevant future episodes (assessing episodic future thinking),udand (c) recalled personally experienced past episodes (assessing episodic memory). Tests ofudnarrative ability and theory of mind were also completed. Results: Performances of participants withudASD were significantly and equally diminished in each condition and, crucially, this diminution wasudindependent of general narrative ability. Conclusions: Given that participants with ASD wereudimpaired in the fictitious scene condition, which does not involve self-projection, we suggest theudunderlying difficulty with episodic memory/future thinking is one of scene construction.