Publications by authors named "Michaela Dewar"

Article Synopsis
  • Recent research indicates that deaf signers excel in visual attention and memory compared to hearing non-signers, particularly in short-term visual tasks.
  • A study showed that deaf individuals not only excelled in retaining detailed visual information over extended periods but also performed better on scene-discrimination tests that were linked to their long-term memory performance.
  • The results suggest that factors like fluency in sign language, extensive practice, and neural plasticity may play a role in the enhanced visual memory abilities of deaf signers, reinforcing their advantage in retaining detailed visual memories.
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Introduction: Possession of one or two e4 alleles of the apolipoprotein E () gene is associated with cognitive decline and dementia risk. Some evidence suggests that physical activity may benefit carriers of the e4 allele differently.

Method: We conducted a systematic review and meta-analysis of studies which assessed differences in the association between physical activity and: lipid profile, Alzheimer's disease pathology, brain structure and brain function in healthy adults.

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A growing body of literature suggests that higher engagement in a range of activities can be beneficial for cognitive health in old age. Such studies typically rely on self-report questionnaires to assess level of engagement. These questionnaires are highly heterogeneous across studies, limiting generalisability.

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Awake quiescence immediately after encoding is conducive to episodic memory consolidation. Retrieval can render episodic memories labile again, but reconsolidation can modify and restrengthen them. It remained unknown whether awake quiescence after retrieval supports episodic memory reconsolidation.

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Visual imagery typically enables us to see absent items in the mind's eye. It plays a role in memory, day-dreaming and creativity. Since coining the terms aphantasia and hyperphantasia to describe the absence and abundance of visual imagery, we have been contacted by many thousands of people with extreme imagery abilities.

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The personal and societal impact of age-related cognitive decline supports the development of effective interventions. While some strategies, such as cognitive training, exercise or socio-intellectual engagement, appear beneficial, few studies have examined the association between personality and intervention efficacy. A systematic review was therefore conducted to summarise and synthesise the literature regarding the influence of personality traits on the effectiveness of non-pharmacological interventions for cognitive ageing.

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Post-navigation awake quiescence, relative to task engagement, benefits the accuracy of a new "cognitive map". This effect is hypothesized to reflect awake quiescence, like sleep, being conducive to the consolidation and integration of new spatial memories. Sleep has been shown to improve cognitive map accuracy over time.

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Many scientific discoveries have been explained by a sudden gaining of insight with regards to an ongoing problem. Insight is characterised by a mental restructuring of acquired information, from which new explicit knowledge can be drawn, leading to qualitative changes in behaviour. Extended sleep facilitates the gaining of insight, possibly because it is conducive to the stabilisation and restructuring of new memory representations via consolidation.

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Newly encoded memories are labile and consolidate over time. The importance of sleep in memory consolidation has been well known for almost a decade. However, recent research has shown that awake quiescence, too, can support consolidation: people remember more new memories if they quietly rest after encoding than if they engage in a task.

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Transient epileptic amnesia (TEA) is an epileptic syndrome characterized by recurrent, brief episodes of amnesia. Patients with TEA often complain of interictal (between attacks) retention deficits, characterised by an 'evaporation' of memories for recent events over days to weeks. Clinical tests of anterograde memory often fail to corroborate these complaints as TEA patients commonly perform within the normal range after the standard 10-30-min delay period.

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Objective: Accelerated long-term forgetting (ALF) occurs when newly learned information decays faster than normal over extended delays. It has been recognised most frequently in temporal lobe epilepsy, including Transient Epileptic Amnesia (TEA), but can also be drug-induced. Little is known about the evolution of ALF over time and its impacts upon other memory functions, such as autobiographical memory (ABM).

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Objective: A recent study indicated that amnesic patients have difficulties not only in describing past and imagined scenarios, but also in describing pictures that are in full view. This finding suggests that impaired memory hampers descriptions of scenarios more broadly. However, no such impairment in picture description in amnesic patients was observed in a related study.

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Flexible spatial navigation depends on cognitive mapping, a function that declines with increasing age. In young adults, a brief period of postnavigation rest promotes the consolidation and integration of spatial memories into accurate cognitive maps. We examined (1) whether rest promotes spatial memory consolidation and integration in older adults; and (2) whether the magnitude of the rest benefit changes with increasing age.

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We describe a patient in whom long-term, therapeutic infusion of the selective gamma-amino-butyric acid type B (GABAB) receptor agonist, baclofen, into the cerebrospinal fluid (CSF) gave rise to three distinct varieties of memory impairment: i) repeated, short periods of severe global amnesia, ii) accelerated long-term forgetting (ALF), evident over intervals of days and iii) a loss of established autobiographical memories. This pattern of impairment has been reported in patients with temporal lobe epilepsy (TLE), in particular the subtype of Transient Epileptic Amnesia (TEA). The amnesic episodes and accelerated forgetting remitted on withdrawal of baclofen, while the autobiographical amnesia (AbA) persisted.

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Flexible spatial navigation, e.g. the ability to take novel shortcuts, is contingent upon accurate mental representations of environments-cognitive maps.

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People retain more new verbal episodic information for at least 7 days if they rest for a few minutes after learning than if they attend to new information. It is hypothesized that rest allows for superior consolidation of new memories. In rodents, rest periods promote hippocampal replay of a recently travelled route, and this replay is thought to be critical for memory consolidation and subsequent spatial navigation.

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Transient epileptic amnesia (TEA) is an epileptic syndrome characterized by recurrent, brief episodes of amnesia. Transient epileptic amnesia is often associated with the rapid decline in recall of new information over hours to days (accelerated long-term forgetting - 'ALF'). It remains unknown how recognition memory is affected in TEA over time.

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People perform better on tests of delayed free recall if learning is followed immediately by a short wakeful rest than by a short period of sensory stimulation. Animal and human work suggests that wakeful resting provides optimal conditions for the consolidation of recently acquired memories. However, an alternative account cannot be ruled out, namely that wakeful resting provides optimal conditions for intentional rehearsal of recently acquired memories, thus driving superior memory.

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Objective: Accelerated long-term forgetting (ALF) is typically defined as a memory disorder in which information that is learned and retained normally over standard intervals (∼30 min) is forgotten at an abnormally rapid rate thereafter. ALF has been reported, in particular, among patients with transient epileptic amnesia (TEA). Previous work in TEA has revealed ALF 24 hr - 1 week after initial memory acquisition.

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Objective: A short wakeful rest immediately after learning boosts memory retention in amnesic patients over several minutes. Here we investigated whether a short wakeful rest could boost memory retention in amnesic patients over a much longer period.

Method: The authors tested 15 patients with amnesia associated with amnestic mild cognitive impairment (MCI)/mild Alzheimer's disease (AD) and 15 age- and-education-matched controls.

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New episodic memories are retained better if learning is followed by a few minutes of wakeful rest than by the encoding of novel external information. Novel encoding is said to interfere with the consolidation of recently acquired episodic memories. Here we report four experiments in which we examined whether autobiographical thinking, i.

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Accelerated Long-term Forgetting (ALF) is the rapid loss of newly acquired memories over days to weeks despite normal retention at standard (~30 min) intervals. It has recently been described in association with epilepsy, particularly the syndrome of Transient Epileptic Amnesia (TEA). The cognitive mechanisms underlying ALF remain uncertain, but disruption either of memory acquisition or consolidation processes has been postulated.

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A brief wakeful rest after new verbal learning enhances memory for several minutes. In the research reported here, we explored the possibility of extending this rest-induced memory enhancement over much longer periods. Participants were presented with two stories; one story was followed by a 10-min period of wakeful resting, and the other was followed by a 10-min period during which participants played a spot-the-difference game.

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