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Retrograde amnesia in dementia and memory disorders
Published in Lars-Göran Nilsson, Nobuo Ohta, Dementia and Memory, 2013
Multiple trace theory (e.g., Nadel and Moscovitch, 1997) states that the hippo-campi (or, at least, the medial temporal lobes) are always involved in the storage, retrieval, and reactivation of episodic memories. According to this theory, sparing of early episodic memories is related to the number of traces that have been laid down (early memories are assumed to have had more reactivations, and thereby more traces), and to the severity and extent of hippocampal damage. Hence, this theory predicts that the severity and extent of episodic retrograde amnesia will be directly proportionate to the severity and extent of hippocampal damage. Moreover, it is assumed that semantic memories are stored eventually elsewhere in the temporal lobes, eventually becoming independent of hippocampal activation, and manifesting a ‘steeper’ temporal gradient than do episodic memories. (Winocur and Moscovitch (2011) have recently proposed a theory of memory transformation, which is very much akin to Cermak’s theory of ‘semanticisation’.) Hence, multiple trace theory generally predicts a ‘flatter’ temporal gradient in episodic memory than does consolidation theory, and it also predicts a steeper gradient in semantic than episodic memories.
Systems consolidation and fear memory generalisation as a potential target for trauma-related disorders
Published in The World Journal of Biological Psychiatry, 2022
Lizeth K. Pedraza, Rodrigo O. Sierra, Lucas de Oliveira Alvares
An alternative view to the standard consolidation model is the Multiple Trace Theory (MTT) and its derivation, the Trace Transformation Theory (Nadel et al. 2000; Moscovitch et al. 2005; Sekeres et al. 2018). It has been proposed to explain some amnestic situations where hippocampal and parahippocampal lesions disrupt detailed episodic memory equally for recent and remote memories (without any retrograde gradient). This framework emphasis that the retrieval of episodic memories induces a subsequent re-encoding, building multiple traces that are mediated by ensembles of hippocampal–neocortical neurons (Nadel et al. 2000). As a consequence, the core prediction of this theory claims that detailed precise episodic memories remain hippocampus-dependent regardless of the memory age.
The Effect of Aging on Memory for Recent and Remote Egocentric and Allocentric Information
Published in Experimental Aging Research, 2019
Antonella Lopez, Alessandro O. Caffò, Giuseppina Spano, Andrea Bosco
What about remote information? Globally, the tasks based on hometown information seemed to reach a level of performance comparable to that shown in table-top tasks based on recently learned spatial relationships among three solids. The increase of age did not seem to affect egocentric and allocentric spatial representation of remote information for recently learned information. This result extends previous findings in which healthy elderly people showed memory was facilitated by familiarity with a place, such as the hometown environment (e.g., Ruggiero, Sergi, & Iachini, 2008). Therefore, information consolidated across a huge number of retrieval episodes seems more solidly preserved in elderly people, and it is likely that the consolidation is preserved in areas other than the hippocampus (Hirshhorn et al., 2011; Moscovitch et al., 2005b; Winocur et al., 2007). Specifically, the results of the present study on remote information seemed to be compatible with the Multiple Trace Theory (MTT, Moscovitch et al. 2005b). When information is well-established in memory, allocentric tasks seem to be fairly accessible for the elderly. The Multiple Trace Theory allows us to imagine a process that starts from repeated acquisitions of information in egocentric format (Moscovitch et al., 2006) and a subsequent transformation into more and more abstract traces. These representations, probably allocentric, or compatible with the allocentric format, may not be rich in detail but are suitable to mentally represent and to experience the environment (e.g., Moscovitch et al., 2005a). In the present study, the familiarity with spatial information used in the hometown tasks seemed to allow elderly and young people to have a comparable performance in landmark positioning tasks (along a route and on a map). These results are in line with previous findings that investigate the effect of familiarity on spatial cognition (e.g., Campbell et al., 2014; Kirasic, 1991; Merriman et al., 2016). With the increase in age, the performance of the elderly did not decrease significantly compared with young people (see Table 2).