Alzheimer’s disease (AD) involves brain atrophy in areas of the core network (i.e. prefrontal, parietal and temporal cortices; McKee et al., 2006). These regions have been implicated in episodic memory (EM), memories for events related to one’s personal past (Buckner et al., 2005), and mental simulation for the future (Addis, Wong, & Schacter, 2007; Hassabis, Kumaran, & Maguire, 2007). Episodic future thinking (EFT) refers to the ability to envision oneself in a future or imagined scene that one has yet to experience (Hassabis et al., 2007). Due to similar neuronal activations in EM and EFT, the episodic simulation hypothesis (ESH) was developed (Schacter & Addis, 2007), arguing that to mentally simulate for the future, one must rely on their
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(2015) paper, including the lack of consideration for SCT which may be a better fit for the results found. Within their study, the authors conclude that they have supported the ESH (Schacter & Addis, 2007) by showing that decline in EM corresponded to decline in EFT for the AD group. However, when examining the means reported it does not appear that this is the case (see Appendix A). According to ESH, EM forms the basis of EFT through the recombination of different memories into a novel scenario. Therefore, decline in EM should parallel a decline in EFT. Yet, examination of the means shows that participants with AD display autobiographical detail deficits only for past as opposed to future generation, whilst their contextual details showed a decline in both past and future generation. If in agreement with ESH, then both autobiographical and contextual elements should present with deficits, but this was not found. Instead, the results fit better with SCT (Hassabis & Maguire, 2007), which, though mentioned briefly, was largely neglected by the authors as an explanation for their results. SCT argues that the hippocampus has a role in providing a context in which everything else falls into place; without such context we would have fragmented EM and EFT (Hassabis & Maguire, 2007). Therefore, hippocampal dysfunction will not lead to complete EM and EFT loss per se, but instead would result in deficits related to providing a context in which the events occur causing a gradual decline in both. As can be seen in El Haj et al., it is the contextual detail that shows deficits for both past and future thinking, supporting the idea that the AD patients may be showing a decline in their ability to provide a context in which events occurred. In contrast, their references to autobiographical detail are less impaired for the future. Consequently, it appears that SCT provides a better explanation for why deficits were found within
(2015) paper, including the lack of consideration for SCT which may be a better fit for the results found. Within their study, the authors conclude that they have supported the ESH (Schacter & Addis, 2007) by showing that decline in EM corresponded to decline in EFT for the AD group. However, when examining the means reported it does not appear that this is the case (see Appendix A). According to ESH, EM forms the basis of EFT through the recombination of different memories into a novel scenario. Therefore, decline in EM should parallel a decline in EFT. Yet, examination of the means shows that participants with AD display autobiographical detail deficits only for past as opposed to future generation, whilst their contextual details showed a decline in both past and future generation. If in agreement with ESH, then both autobiographical and contextual elements should present with deficits, but this was not found. Instead, the results fit better with SCT (Hassabis & Maguire, 2007), which, though mentioned briefly, was largely neglected by the authors as an explanation for their results. SCT argues that the hippocampus has a role in providing a context in which everything else falls into place; without such context we would have fragmented EM and EFT (Hassabis & Maguire, 2007). Therefore, hippocampal dysfunction will not lead to complete EM and EFT loss per se, but instead would result in deficits related to providing a context in which the events occur causing a gradual decline in both. As can be seen in El Haj et al., it is the contextual detail that shows deficits for both past and future thinking, supporting the idea that the AD patients may be showing a decline in their ability to provide a context in which events occurred. In contrast, their references to autobiographical detail are less impaired for the future. Consequently, it appears that SCT provides a better explanation for why deficits were found within