Mental simulation of future scenarios in transient global amnesia

• Published in: Neuropsychologia 2014-10, Vol.63, p.1-9
• Main Authors: Juskenaite, Aurelija, Quinette, Peggy, Desgranges, Béatrice, Sayette, Vincent de La, Viader, Fausto, Eustache, Francis
• Format: Article
• Language: English
• Subjects: Adult and adolescent clinical studies; Aged; Aged, 80 and over; Amnesia, Transient Global - psychology; Biological and medical sciences; Disorders of higher nervous function. Focal brain diseases. Central vestibular syndrome and deafness. Brain stem syndromes; Episodic memory; Female; Humans; Imagination; Life Sciences; Male; Medical sciences; Memory, Episodic; Mental Recall; Mental simulation of the future; Mental time travel; Middle Aged; Nervous system (semeiology, syndromes); Neurology; Neurons and Cognition; Organic mental disorders. Neuropsychology; Psychology. Psychoanalysis. Psychiatry; Psychopathology. Psychiatry; Time Factors; Transient global amnesia
• ISSN: 0028-3932; 1873-3514
• DOI: 10.1016/j.neuropsychologia.2014.08.002

Researchers exploring mental time travel into the future have emphasized the role played by episodic memory and its cerebral substrates. Recently, owing to controversial findings in amnesic patients, this role has become a matter of intense debate. In order to understand whether episodic memory is indeed crucial to future thinking, we assessed this ability in 11 patients during an episode of transient global amnesia (TGA), a unique and severe amnesic syndrome that primarily affects episodic memory. In the first of two experiments, TGA patients were asked to recall personal past events as well as to imagine personal future events, without any guidance regarding content. Under this condition, compared with controls, they provided fewer past and fewer future events, and the latter were less closely related to their personal goals. Furthermore, TGA patients׳ descriptions of past and future events were scant, containing fewer descriptive elements in total and fewer internal details. In order to assess whether TGA patients might have been basing their future event narratives on their general knowledge about how these events usually unfold, in our second experiment, we asked them to imagine future events in response to short descriptions of common scenarios. Under this condition, inherently eliciting less detailed descriptions, not only were all the TGA patients able to describe common events as happening in the future, but their narratives contained comparable amounts of internal detail to those of controls, despite being less detailed overall. Taken together, our results indicate that severe amnesia interferes with TGA patients׳ ability to envisage their personal past and future on a general level as well as in detail, but less severely affects their ability to imagine common scenarios, which are not related to their personal goals, probably owing to their preserved semantic memory, logical reasoning and ability to create vivid mental images. •TGA patients imagined past and future events without guidance regarding their content.•TGA patients provided fewer events than controls and their content was less detailed.•Imagination of supplied common events was only slightly disturbed in TGA patients.•Severe amnesia mostly affects the ability to envisage personal past and future.