Disruption of temporally extended self-memory system following traumatic brain injury Cécile Coste a,b,c , Béatrice Navarro a,b , Claire Vallat-Azouvi d , Marie Brami e , Philippe Azouvi f , Pascale Piolino a,b,g,n a Paris Descartes University, Sorbonne Paris Cité, Institute of Psychology, Memory and Cognition Laboratory, France b Inserm UMR S 894, Center of Psychiatry and Neuroscience, Paris Descartes University, France c Adults Neurological Unity, Hôpitaux de Saint-Maurice, Saint-Maurice, France d UEROS-UGECAM, Raymond Poincaré Hospital, Garches, France e ADEP-CICL, Puteaux, France f Physical Medicine and Rehabilitation Service, Raymond Poincaré Hospital, Garches, France g Institut Universitaire de France, France article info Article history: Received 3 August 2014 Received in revised form 25 February 2015 Accepted 14 March 2015 Available online 17 March 2015 Keywords: Self-memory system Autobiographical memory Future Mental time travel Self-concept Executive function Working memory binding Verbal fluency Traumatic brain injury abstract We investigated for the first time the episodic/semantic distinction in remembering the past and ima- gining the future in traumatic brain injury (TBI), and explored cognitive mechanisms that may underlie their deficits. Fifteen severe TBI patients and 15 control participants performed a battery of neu- ropsychological tests and a set of verbal fluency tasks designed to assess semantic (personality traits knowledge and general events), and episodic (specific events and details) facets of self-representations according to three time periods (remote/retrograde past, recent/anterograde past, future). Compared to controls, TBI patients showed deficits in both semantic and episodic self-representations, regardless of the time period, and controlling for basic cognitive functions. By contrast, a subjective evaluation of self- concept measuring the degree of certitude and the valence of self did not differ between patients and controls. The deficits were mainly predicted by altered executive function (i.e., updating) for past periods, as well as by general semantic and feature binding in working memory for the future period, in- dependently of the injury characteristics. For controls, only episodic self-representation for each time period was mediated by executive or working memory functions, while semantic self-representation was mediated by the certitude of the self. This study highlights the dual role of semantic and episodic re- presentations in temporally extended self, and shows the global disruption of self-representations across extended time in severe TBI. This encourages the extension of past and future thinking research to TBI populations to provide important insights into the nature and origin of these deficits and their role in recovery and to suggest future lines of research on rehabilitation procedures. & 2015 Elsevier Ltd. All rights reserved. 1. Introduction The literature documents some well-known cases of traumatic brain injury (TBI) patients who seem to live in a timeless world, in a sort of perpetual present experiencing difficulties in travelling back and forward into subjective time (i.e., mental time travel) to recall past personal events or imagine future ones (Klein, 2010; Tulving, 2002). One of these patients is the well-known case KC (Tulving et al., 1988) who described his mind as a blank when he tried to think of precise events in his past or his future (for a review of case KC, see Rosenbaum et al., 2004). Despite this fa- mous observation, very few studies have been conducted to in- vestigate mental time travel in TBI patients. To date only one study has examined these skills in a group of nine moderate to severe TBI patients asked to report series of specific past or future events, revealing similar deficits in both temporalities (Rasmussen and Berntse, 2014). Given the importance of future behaviour in the rehabilitation and community/vocational integration of TBI pa- tients (Dritschel et al., 1998; Hewitt et al., 2006), this area is well worth addressing. Since the princeps case study KC, the literature on future thinking has been largely conducted in line with Tulving's (2002) conception of episodic memory. According to Tulving, episodic memory allows humans to travel mentally and makes it possible to both “re-experience” past events and “pre-experience” future Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/neuropsychologia Neuropsychologia http://dx.doi.org/10.1016/j.neuropsychologia.2015.03.014 0028-3932/& 2015 Elsevier Ltd. All rights reserved. n Corresponding author at: Memory and Cognition Lab. at Centre de Psychiatrie et Neurosciences, Inserm UMR 894, 2 Ter rue d’Alésia, 75014 Paris, France. Fax: þ33 1 55 20 58 53. E-mail address: pascale.piolino@parisdescartes.fr (P. Piolino). Neuropsychologia 71 (2015) 133–145