حل مشکل نامشخص در اختلال خفیف شناختی مبتلا به فراموشی: ارتباط حافظه اپیزودیک برای نسل راه حل مناسب
|کد مقاله||سال انتشار||مقاله انگلیسی||ترجمه فارسی||تعداد کلمات|
|33702||2015||8 صفحه PDF||سفارش دهید||محاسبه نشده|
Publisher : Elsevier - Science Direct (الزویر - ساینس دایرکت)
Journal : Neuropsychologia, Volume 68, February 2015, Pages 168–175
It is well accepted that the medial temporal lobes (MTL), and the hippocampus specifically, support episodic memory processes. Emerging evidence suggests that these processes also support the ability to effectively solve ill-defined problems which are those that do not have a set routine or solution. To test the relation between episodic memory and problem solving, we examined the ability of individuals with single domain amnestic mild cognitive impairment (aMCI), a condition characterized by episodic memory impairment, to solve ill-defined social problems. Participants with aMCI and age and education matched controls were given a battery of tests that included standardized neuropsychological measures, the Autobiographical Interview (Levine et al., 2002) that scored for episodic content in descriptions of past personal events, and a measure of ill-defined social problem solving. Corroborating previous findings, the aMCI group generated less episodically rich narratives when describing past events. Individuals with aMCI also generated less effective solutions when solving ill-defined problems compared to the control participants. Correlation analyses demonstrated that the ability to recall episodic elements from autobiographical memories was positively related to the ability to effectively solve ill-defined problems. The ability to solve these ill-defined problems was related to measures of activities of daily living. In conjunction with previous reports, the results of the present study point to a new functional role of episodic memory in ill-defined goal-directed behavior and other non-memory tasks that require flexible thinking. Our findings also have implications for the cognitive and behavioural profile of aMCI by suggesting that the ability to effectively solve ill-defined problems is related to sustained functional independence.
Recent evaluations of episodic memory have provided compelling evidence that the function of episodic autobiographical memory is not just to recall the past, but to think about the future and plan for it. This is supported by reports of overlap between retrieving past events and constructing future scenes and scenarios, in terms of the underlying neural activity (Addis et al., 2007 and Schacter, 2012) and behavioural performance in healthy adults (Addis et al., 2010, Addis et al., 2008 and Anderson et al., 2012) as well as in patients with brain damage or deterioration (Addis et al., 2009b and Hassabis et al., 2007). A common element is the involvement of the medial temporal lobes (MTL). The MTL, and the hippocampus in particular, are presumed to facilitate episodic remembering by binding together co-occurring details to form the conscious re-experience of that event (Cipolotti and Moscovitch, 2005, Moscovitch, 1995, Nadel and Moscovitch, 1997 and Nadel and Moscovitch, 2001). These same hippocampal processes can flexibly recombine details from memories of experienced events, allowing for the creation of novel scenes and future scenarios which simulate episodic memories. It is hypothesized that these simulations also guide goal-directed behaviour (Atance and O’Neill, 2001, Bar, 2007, Bar, 2009, Barbey et al., 2009 and Szpunar et al., 2013). In earlier studies we tested the hypothesis that MTL-mediated episodic memory processes that support past event reconstruction and future event simulation also serve as a mechanism for solving ill-defined problems (Sheldon et al., 2011 and Vandermorris et al., 2013). Ill-defined problems are those that do not have a set routine or algorithm to reach a guaranteed solution. Rather, there are typically multiple ways to solve the tasks (Pretz et al., 2003). Navigating a social situation and planning a vacation are examples of ill-defined tasks. Well-defined or closed-ended problems, on the other hand, are tasks for which there is a guaranteed solution if a set script or solution path is followed. Examples of well-defined tasks are making coffee and solving math problems. While finding the correct solutions to well-defined problems can rely on schemas, scripts or algorithms, which are supported by semantic memory processes, these are not as useful for solving ill-defined problems. Ill-defined problems are more likely to rely on flexible, reconstructive episodic memory processes to help create simulations to examine possible solutions (Sheldon et al., 2011). In support of this hypothesis, we found that populations with known loss of MTL-mediated episodic memory processes, such as older adults and individuals with temporal lobe epilepsy (TLE) with confirmed hippocampal damage, were impaired on a test of ill-defined social problem solving (Platt and Spivack, 1975). That test, known as the Means End Problem Solving (MEPS) test, is composed of ten vignettes, each consisting of a social problem for which a participant is asked to describe verbally the ideal solution. Both populations generated less effective solutions compared to healthy control counterparts. By using a modified scoring procedure taken from the Autobiographical Interview (AI; Levine et al., 2002) to score the MEPS solution descriptions for the amount of episodic content in the simulations, we found that older adults and individuals with TLE generated solutions that had less episodic detail compared to their matched counterparts. The amount of episodic detail in their simulations, and in their autobiographical narratives, was correlated with the effectiveness of their solutions on the MEPS. We replicated and extended these findings in an older adult population by showing that the contribution of these episodic memory processes to effective problem solving was specific to ill-defined tasks (Vandermorris et al., 2013). The current investigation expands on these findings by examining problem solving in relation to memory processes in amnestic mild cognitive impairment (aMCI). aMCI as a precursor to Alzheimer’s disease (AD), is characterized, in early stages, by a selective impairment in episodic memory, indicated by declines on tests of anterograde memory. The extent of this impairment is typically between declines in memory associated with aging and those associated with AD (Anderson et al., 2012, Martinelli et al., 2013 and Vandermorris et al., 2013). As with AD, the nature of aMCI memory loss has been attributed to neuroanatomical and physiological changes in the MTL (Masdeu et al., 2005). The present study has a number of theoretical and practical implications. Theoretically, understanding the link between memory processes and higher cognitive tasks like problem solving will add to our understanding of the functions of detailed recollection. On the practical side, we can determine if aMCI episodic memory deficits relate to poor problem solving performance. In addition, the study addresses the controversy over whether aMCI, along with selective MTL-driven episodic deficits (Murphy et al., 2008), is also associated with semantic memory deficits (Dudas et al., 2005 and Leyhe et al., 2009) in terms of autobiographical retrieval. Finally, we asked if investigating problem solving in aMCI patients will help elucidate how aMCI impacts activities of daily living (Anstey et al., 2013, Farias et al., 2006 and Fauth et al., 2013). By determining whether aMCI negatively affects problem solving, we might be able to provide some insights into how memory conditions relate to real-world tasks such as solving ill-defined problems.
نتیجه گیری انگلیسی
Solving problems that are ill-defined and ambiguous requires different cognitive mechanisms from solving problems that are well rehearsed and can rely on scripts and schemas. Here, we show that the same MTL-mediated processes that support recollecting the episodic elements of a past event also support creating effective solutions to ill-defined problems. These results contribute to our understanding of detailed recollection by showing that solution generation is one of its functions, which fits well with contemporary views of hippocampal contributions to flexible cognition (Rubin and Umanath, 2014). By illustrating this link in individuals with aMCI, we illuminate a potential contribution of episodic memory loss that results from MTL impairment to functional independence and daily activity. This information can be used to motivate future therapeutic decision-making for aMCI populations and others with related memory deficits.