Autobiographical Memory and Autoneotic Consciousness in a case of Semantic Dementia
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Investigations of retrograde amnesia have contributed to a better understanding of the cerebral structures involved in remote memory. Such studies have suggested that neocortical regions such as the anterior temporal lobe play a major role in both the storage and retrieval of remote episodic and semantic information. Semantic dementia (SD), characterised as a focal anterior temporal lobe atrophy, offers an opportunity to study episodic remote memory, especially in the absence of day-to-day memory dysfunctioning, which takes place in permanent amnesic syndromes. Few studies have investigated autobiographical retrograde amnesia in SD. We present the findings from a patient (AT) at the early stage of SD. First, we have compared episodic and semantic components of autobiographical memory using two specially designed fluency tasks. The results demonstrated good recall of autobiographical events from all time periods and poor retrieval of names of acquaintances, albeit to a lesser degree, with respect to recent life. Second, we have investigated strictly episodic autobiographical memory and autonoetic consciousness by means of a sophisticated autobiographical test and the Remember/Know procedure which used a more stringent criterion of episodicity. The results demonstrated a relatively good recall of autobiographical memories (whatever their nature) but poor retrieval of remote specific detailed memories compared to recent ones. Moreover, patient AT provided Remember judgements to the same extent as control subjects regardless of the time interval covered although his responses were not justified in terms of the actual contextual information retrieved beyond the last 5 years. These findings provide further evidence that strictly episodic recollection is restricted to the recent past in SD. These data are discussed according to their relevance to the episodic and semantic distinction and to models of long-term memory consolidation.Keywords:
Autobiographical Memory
Retrospective memory
Retrograde amnesia
Semantic dementia
Chronesthesia
Abstract Case Y.K. has severe anterograde amnesia and a selective loss of specific personal episodes in his remote memories (Hirano & Noguchi, 1998). In this paper, we attempted to analyze remembering (R) and knowing (K) responses, that is, the relationship between autobiographical remembering and remembering accompanied by subjective experience. Although the rate of R responses was significantly higher than that of K responses in control subjects, Y.K.'s R responses were rare in all subtypes of remote memories. Based on these results, we conclude that Y.K.'s memories on autobiographical incident task were not based on episodic memory but rather on semantic memory. Thus, the autobiographical incidents he could recall were not episodic memory, and his semantic memory made him recall information as fact rather than episode.
Autobiographical Memory
Childhood amnesia
Reconstructive memory
Retrospective memory
Retrograde amnesia
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Retrospective memory
Autobiographical Memory
Childhood amnesia
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Investigations of retrograde amnesia have contributed to a better understanding of the cerebral structures involved in remote memory. Such studies have suggested that neocortical regions such as the anterior temporal lobe play a major role in both the storage and retrieval of remote episodic and semantic information. Semantic dementia (SD), characterised as a focal anterior temporal lobe atrophy, offers an opportunity to study episodic remote memory, especially in the absence of day-to-day memory dysfunctioning, which takes place in permanent amnesic syndromes. Few studies have investigated autobiographical retrograde amnesia in SD. We present the findings from a patient (AT) at the early stage of SD. First, we have compared episodic and semantic components of autobiographical memory using two specially designed fluency tasks. The results demonstrated good recall of autobiographical events from all time periods and poor retrieval of names of acquaintances, albeit to a lesser degree, with respect to recent life. Second, we have investigated strictly episodic autobiographical memory and autonoetic consciousness by means of a sophisticated autobiographical test and the Remember/Know procedure which used a more stringent criterion of episodicity. The results demonstrated a relatively good recall of autobiographical memories (whatever their nature) but poor retrieval of remote specific detailed memories compared to recent ones. Moreover, patient AT provided Remember judgements to the same extent as control subjects regardless of the time interval covered although his responses were not justified in terms of the actual contextual information retrieved beyond the last 5 years. These findings provide further evidence that strictly episodic recollection is restricted to the recent past in SD. These data are discussed according to their relevance to the episodic and semantic distinction and to models of long-term memory consolidation.
Autobiographical Memory
Retrospective memory
Retrograde amnesia
Semantic dementia
Chronesthesia
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Memory disorder
Retrograde amnesia
Memoria
Anterograde amnesia
Retrospective memory
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Autobiographical Memory
Retrospective memory
Retrograde amnesia
Declarative memory
Long-term memory
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We described the case of a patient affected by a progressive memory disorder associated with prevalent temporal lobe atrophy. This deficit seems to be pure in the sense that it has not been found to overlap with other cognitive deficits (intellectual, linguistic, perceptual, visuo-spatial etc.) for a long time. Furthermore, despite his impaired knowledge, the autobiographical memory of the patient was largely intact. This case therefore represents a form of amnesia without dementia, and supports the hypothesis that there is a partial distinction between semantic and episodic memory.
Autobiographical Memory
Semantic dementia
Retrospective memory
Memory disorder
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Objective: The temporal gradient in patients with Korsakoff’s syndrome has been of particular interest in the literature, as many studies have found evidence for a steep temporal gradient, but others have observed more uniform remote memory impairment across all past time periods. Inconsistencies might be the result of the nature of remote memory impairment under study (i.e., nonpersonal or autobiographical memory) and of methodological differences in the examination of remote memory loss. The aim of this study was to examine whether differences between autobiographical memory interview (AMI) and autobiographical interview (AI) procedures influence the presence of a temporal gradient in semantic and episodic autobiographical memory in Korsakoff patients. Method: The procedure used in the present study combined the AMI and AI into one study session. We compared the performance of 20 patients with Korsakoff’s syndrome and 27 healthy controls. First, participants were asked to recall knowledge from different life periods. Second, participants were asked to recall memories from five life periods. Thirdly, participants were asked to rate their subjective experience of each event recalled on a 5-point scale. Finally, we analyzed the findings in terms of all the memories recalled versus the first memory from each life-period only. Results: Both the AMI and the AI showed a temporally graded retrograde amnesia in the Korsakoff patients for personal semantic and episodic autobiographical memories. The pattern of amnesia in Korsakoff patients was not affected by examining only one event per life-period. Subjective ratings of recalled memories were largely comparable between the groups. Conclusions: The findings were generally consistent across the AMI and AI. Varying the number of events did not affect the pattern of the gradient. Hence, the temporal gradient in Korsakoff patients is not an artefact of either the AMI or the AI method.
Autobiographical Memory
Childhood amnesia
Retrograde amnesia
Retrospective memory
Memory errors
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The ability to envisage personally relevant events at a future time point represents an incredibly sophisticated cognitive endeavor and one that appears to be intimately linked to episodic memory integrity. Far less is known regarding the neurocognitive mechanisms underpinning the capacity to envisage non-personal future occurrences, known as semantic future thinking. Moreover the degree of overlap between the neural substrates supporting episodic and semantic forms of prospection remains unclear. To this end, we sought to investigate the capacity for episodic and semantic future thinking in Alzheimer's disease (n = 15) and disease-matched behavioral-variant frontotemporal dementia (n = 15), neurodegenerative disorders characterized by significant medial temporal lobe and frontal pathology. Participants completed an assessment of past and future thinking across personal (episodic) and non-personal (semantic) domains, as part of a larger neuropsychological battery investigating episodic and semantic processing, and their performance was contrasted with 20 age- and education-matched healthy older Controls. Participants underwent whole-brain T1 weighted structural imaging and voxel-based morphometry analysis was conducted to determine the relationship between grey matter integrity and episodic and semantic future thinking. Relative to Controls, both patient groups displayed marked future thinking impairments, extending across episodic and semantic domains. Analyses of covariance revealed that while episodic future thinking deficits could be explained solely in terms of episodic memory proficiency, semantic prospection deficits reflected the interplay between episodic and semantic processing. Distinct neural correlates emerged for each form of future simulation with differential involvement of prefrontal, lateral temporal and medial temporal regions. Notably, the hippocampus was implicated irrespective of future thinking domain, with the suggestion of lateralization effects depending on the type of information being simulated. Whereas episodic future thinking related to right hippocampal integrity, semantic future thinking was found to relate to left hippocampal integrity. Our findings support previous observations of significant medial temporal lobe involvement for semantic forms of prospection and point to distinct neurocognitive mechanisms which must be functional to support future-oriented forms of thought across personal and non-personal contexts.
Semantic dementia
Chronesthesia
Retrospective memory
Autobiographical Memory
Neurocognitive
Reconstructive memory
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Semantic dementia
Autobiographical Memory
Retrospective memory
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Semantic dementia refers to a multi-modal loss of semantic knowledge, resulting from degeneration of the anterior temporal neocortex. Loss of information is not absolute. We have previously demonstrated (Snowden, Griffiths,& Neary, 1994, 1995) that autobiographical experience has an important role in influencing information preservation, and have argued that patients' preserved experiential memory helps to invest words and objects with meaning that would otherwise be lost. Those studies suggested a particularly critical role of current autobiographical experience. The present study aimed to explore the generality of the observed current information superiority in an investigation of patients' knowledge of celebrities, understanding of a contemporary and obsolete monetary system, and autobiographical memory. Performance was superior for contemporary (recent) than for past (remote) information, both factual and autobiographic, suggesting an inverse of the temporally graded pattern of retrograde memory found in classical amnesia. It is argued that the findings are consistent with explanations of the "temporal gradient" effect of retrograde amnesia in terms of qualitative differences in recent and remote memories. The findings indicate a bidirectional interaction between autobiographic and semantic memorising, and emphasise a continuous, dynamic interrelationship rather than a time-limited role. An important distinction is highlighted between autobiographical and impersonal episodic memory. The findings have significant theoretical implications both for the understanding of retrograde memory function and the interrelationship between episodic and semantic memory.
Autobiographical Memory
Retrograde amnesia
Semantic dementia
Retrospective memory
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