Focal autobiographical amnesia in association with transient epileptic amnesia.
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Although problems with remembering significant events from the past (e.g. holidays, weddings, etc.) have been reported previously in patients with transient epileptic amnesia (TEA), to date there have been no detailed studies of autobiographical memory in patients with this disorder. To investigate this issue, a 68-year-old right-handed man (R.G.) who suffered from TEA and reported significant autobiographical memory problems was tested on a battery of neuropsychological tests of anterograde and remote memory. Tests of autobiographical memory revealed that R.G. was unable to evoke detailed autobiographical recollections from a substantial part of his life. By contrast, he performed well on tests of new learning and general knowledge and possessed good personal semantic information about his past. In summary, a distinct form of autobiographical amnesia, which is characterized by loss of experiential remembering of significant events, may be associated with TEA. It is proposed that the autobiographical memory deficit seen in the disorder may result from the progressive erasure of cortically based memory representations. This case adds to growing evidence for a dissociation between mechanisms subserving anterograde memory and those required to evoke remote episodic memories. (+info)
Sensory-perceptual episodic memory and its context: autobiographical memory.
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Episodic memory is reconceived as a memory system that retains highly detailed sensory perceptual knowledge of recent experience over retention intervals measured in minutes and hours. Episodic knowledge has yet to be integrated with the autobiographical memory knowledge base and so takes as its context or referent the immediate past of the experiencing self (or the 'I'). When recalled it can be accessed independently of content and is recollectively experienced. Autobiographical memory, in contrast, retains knowledge over retention intervals measured in weeks, months, years, decades and across the life span. Autobiographical knowledge represents the experienced self (or the 'me'), is always accessed by its content and, when accessed, does not necessarily give rise to recollective experience. Instead, recollective experience occurs when autobiographical knowledge retains access to associated episodic memories. In this reworking of the 'episodic memory' concept autobiographical memory provides the instantiating context for sensory-perceptual episodic memory. (+info)
Neuroimaging studies of autobiographical event memory.
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Commonalities and differences in findings across neuroimaging studies of autobiographical event memory are reviewed. In general terms, the overall pattern across studies is of medial and left-lateralized activations associated with retrieval of autobiographical event memories. It seems that the medial frontal cortex and left hippocampus in particular are responsive to such memories. However, there are also inconsistencies across studies, for example in the activation of the hippocampus and dorsolateral prefrontal cortex. It is likely that methodological differences between studies contribute to the disparate findings. Quantifying and assessing autobiographical event memories presents a challenge in many domains, including neuroimaging. Methodological factors that may be pertinent to the interpretation of the neuroimaging data and the design of future experiments are discussed. Consideration is also given to aspects of memory that functional neuroimaging might be uniquely disposed to examine. These include assessing the functionality of damaged tissue in patients and the estimation of inter-regional communication (effective connectivity) between relevant brain regions. (+info)
First Person Account: landing a Mars lander.
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The article that follows is part of the Schizophrenia Bulletin's ongoing First Person Account series. We hope that mental health professionals--the Bulletin's primary audience--will take this opportunity to learn about the issues and difficulties confronted by consumers of mental health care. In addition, we hope that these accounts will give patients and families a better sense of not being alone in confronting the problems that can be anticipated by persons with serious emotional difficulties. We welcome other contributions from patients, ex-patients, or family members. Our major editorial requirement is that such contributions be clearly written and organized, and that a novel or unique aspect of schizophrenia be described, with special emphasis on points that will be important for professionals. Clinicians who see articulate patients with experiences they believe should be shared might encourage these patients to submit their articles to Schizophrenia Bulletin, First Person Accounts, EEI Communications, 66 Canal Center Plaza, Suite 200, Alexandria, VA 22314.--The Editors. (+info)
The early years of molecular biology: personal recollections.
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The early years of molecular biology were characterized by a strong interaction between theory and experiment. This included the elucidation of the structure of DNA itself; genetic fine structure, recombination and repair; DNA replication; template-directed protein synthesis; the universality of the triplet genetic code, and the co-linearity of the DNA sequence of structural genes and the sequence of amino acids in proteins. The principle of co-linearity was later modified when split genes were discovered. It is suggested that accurate splicing of gene transcripts might also be template directed. In 1958 Crick proposed a 'central dogma' of molecular biology stating that information could not be transmitted from proteins to DNA. Nevertheless, proteins can chemically modify DNA, and this is now known to have strong effects on gene expression. (+info)
Autobiographical amnesia and accelerated forgetting in transient epileptic amnesia.
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BACKGROUND: Recurrent brief isolated episodes of amnesia associated with epileptiform discharges on EEG recordings have been interpreted as a distinct entity termed transient epileptic amnesia (TEA). Patients with TEA often complain of autobiographical amnesia for recent and remote events, but show normal anterograde memory. OBJECTIVE: To investigate (a) accelerated long term forgetting and (b) autobiographical memory in a group of patients with TEA. METHODS: Seven patients with TEA and seven age matched controls were evaluated on a range of anterograde memory tasks in two sessions separated by 6 weeks and by the Galton-Crovitz test of cued autobiographical memory. RESULTS: Patients with TEA showed abnormal long term forgetting of verbal material, with virtually no recall after 6 weeks. In addition, there was impaired recall of autobiographical memories from the time periods 1985-89 and 1990-94 but not from 1995-1999. CONCLUSIONS: TEA is associated with accelerated loss of new information and impaired remote autobiographical memory. There are a number of possible explanations including ongoing subclinical ictal activity, medial temporal lobe damage as a result of seizure, or subtle ischaemic pathology. Future analyses should seek to clarify the relationship between aetiology, seizure frequency, and degree of memory impairment. (+info)
Ecphory of autobiographical memories: an fMRI study of recent and remote memory retrieval.
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Ecphory occurs when one recollects a past event cued by a trigger, such as a picture, odor, or name. It is a central component of autobiographical memory, which allows us to "travel mentally back in time" and re-experience specific events from our personal past. Using fMRI and focusing on the role of medial temporal lobe (MTL) structures, we investigated the brain bases of autobiographical memory and whether they change with the age of memories. Importantly, we used an ecphory task in which the remote character of the memories was ensured. The results showed that a large bilateral network supports autobiographical memory: temporal lobe, temporo-parieto-occipital junction, dorsal prefrontal cortex, medial frontal cortex, retrosplenial cortex and surrounding areas, and MTL structures. This network, including MTL structures, changed little with the age of the memories. (+info)
Memories for emotional autobiographical events following unilateral damage to medial temporal lobe.
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Abnormalities of both memory and emotion have been reported in patients with unilateral damage to the anteromedial temporal lobe, probably reflecting the functions of the amygdala and hippocampus in these processes. Emotion and memory are also known to interact: emotional experiences often leave remarkably durable autobiographical memories. To explore this interaction, and to extend prior studies to the domain of autobiographical memory, we investigated the recollection of real-life emotional events in patients with unilateral damage to the anteromedial temporal lobe. Twenty-three patients who had undergone unilateral temporal lobectomy for the treatment of epilepsy (12 left, 11 right) and 20 healthy comparison participants completed an emotional autobiographical memory test. Participants were asked to recollect their five most emotional memories from any time in their lives and then they completed a word-cued autobiographical memory task. Participants dated each memory and gave ratings on scales of pleasantness, intensity, significance, novelty, vividness and frequency of rehearsal. Left temporal lobectomy (LTL) and healthy comparison groups generated similar numbers of pleasant and unpleasant memories, whereas the right temporal lobectomy (RTL) group produced significantly fewer memories of unpleasant events (P < 0.01). When memories were further categorized according to pleasantness and intensity, the RTL group produced significantly fewer unpleasant/high intensity memories than the other groups (P < 0.01). All groups reported more memories from between the ages of 10 and 30 (the so-called autobiographical memory 'bump'). The results demonstrate a positive bias in the recollection of autobiographical memory following right-sided anteromedial temporal damage. This finding is consistent with the notion that the right, but not the left, anteromedial temporal lobe is involved in the retrieval of negatively valenced, high-intensity memories. (+info)