Rest-related consolidation protects the fine detail of new memories

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. It is not yet known how exactly this rest-related consolidation benefits new memories, and whether it affects the fine detail of new memories. Using a sensitive picture recognition task, we show that awake quiescence aids the fine detail of new memories. Young adults were significantly better at discriminating recently encoded target pictures from similar lure pictures when the initial encoding of target pictures had been followed immediately by 10 minutes of awake quiescence than an unrelated perceptual task. This novel finding indicates that, in addition to influencing how much we remember, our behavioural state during wakeful consolidation determines, at least in part, the level of fine detail of our new memories. Thus, our results suggest that rest-related consolidation protects the fine detail of new memories, allowing us to retain detailed memories

On the role and nature of retroactive interference in anterograde amnesia

Recent research has elucidated significantly improved delayed recall in patients with severe anterograde amnesia following an unfilled as opposed to a filled retention interval. Such findings are of great interest as they suggest that some anterograde amnesiacs are able to retain material for much longer than usual when Retroactive Interference is kept minimal. The research thus provides a novel cognitive hypothesis for the severe forgetting in anterograde amnesia, namely a greatly heightened susceptibility to Retroactive Interference. The aim of this thesis was to further examine such phenomenon and hypothesis. More specifically the main aim was to (a) investigate which cognitive conditions are required for a benefit of minimal Retroactive Interference to emerge in anterograde amnesiacs; and thus how specific their susceptibility to Retroactive Interference is, and (b) which cognitive processes underlie the benefit of minimal Retroactive Interference in such patients. A secondary aim was to review and further explore Müller and Pilzecker’s (1900) original research and theory of Retroactive Interference in forgetting in healthy people, to investigate the effects of Retroactive Interference on age related memory decline as well as to examine potential neural correlates of the benefit of minimal Retroactive Interference. Various samples of anterograde amnesia patients (Focal injury and MCI) and healthy participants were tested by means of a range of experimental manipulations in order to explore these questions. The research elucidated that any material or distraction (‘diversion Retroactive Interference’) had to be removed during the delay interval for anterograde amnesiacs to show improved delayed recall. Moreover the results of this thesis strongly suggest that minimal Retroactive Interference allows for improved Long Term Memory formation in at least some anterograde amnesia patients. These two main findings were also made for the healthy participants, albeit to a greatly reduced extent. In conclusion, the present research provides further and novel detailed evidence for a ‘diversion’ Retroactive Interference hypothesis of forgetting in pathological and normal forgetting alike

A study on episodic memory reconsolidation that tells us more about consolidation

Awake quiescence immediately after encoding is conducive to episodic memory consolidation. Retrieval can render episodic memories labile again, but reconsolidation can modify and re-strengthen them. It remained unknown whether awake quiescence after retrieval supports episodic memory reconsolidation. We sought to examine this question via an object-location memory paradigm. We failed to probe the effect of quiescence on reconsolidation, but we did observe an unforeseen ‘delayed’ effect of quiescence on consolidation. Our findings reveal that the beneficial effect of quiescence on episodic memory consolidation is not restricted to immediately following encoding but can be achieved at a delayed stage and even following a period of task engagement

Boosting Long-term Memory via Wakeful Rest: Intentional Rehearsal is not Necessary, Automatic Consolidation is Sufficient.

<div><p>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. Here we utilised non-recallable words to examine whether wakeful rest boosts long-term memory, even when new memories could not be rehearsed intentionally during the wakeful rest delay. The probing of non-recallable words requires a recognition paradigm. Therefore, we first established, via Experiment 1, that the rest-induced boost in memory observed via free recall can be replicated in a recognition paradigm, using concrete nouns. In Experiment 2, participants heard 30 non-recallable non-words, presented as ‘foreign names in a bridge club abroad’ and then either rested wakefully or played a visual spot-the-difference game for 10 minutes. Retention was probed via recognition at two time points, 15 minutes and 7 days after presentation. As in Experiment 1, wakeful rest boosted recognition significantly, and this boost was maintained for at least 7 days. Our results indicate that the enhancement of memory via wakeful rest is <i>not</i> dependent upon intentional rehearsal of learned material during the rest period. We thus conclude that consolidation is <i>sufficient</i> for this rest-induced memory boost to emerge. We propose that wakeful resting allows for superior memory consolidation, resulting in stronger and/or more veridical representations of experienced events which can be detected via tests of free recall and recognition.</p></div

Accelerated Long-Term Forgetting Can Become Apparent Within 3-8 Hours of Wakefulness in Patients With Transient Epileptic Amnesia

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. It is unclear, however, if ALF observed 24 hr after acquisition reflects (a) an impairment of sleep consolidation processes taking place during the first night's sleep, or (b) an impairment of daytime consolidation processes taking place during the day of acquisition. Here we focus on the daytime-forgetting hypothesis of ALF in TEA by tracking in detail the time course of ALF over the day of acquisition, as well as over 24 hr and 1 week. METHOD: Eleven TEA patients who showed ALF at 1 week and 16 matched controls learned 4 categorical word lists on the morning of the day of acquisition. We subsequently probed word-list retention 30 min, 3 hr, and 8 hr postacquisition (i.e., over the day of acquisition), as well as 24-hr and 1-week post acquisition. RESULTS: ALF became apparent in the TEA group over the course of the day of acquisition 3-8 hr after learning. No further forgetting was observed over the first night in either group. CONCLUSIONS: The results of this study show that ALF in TEA can result from a deficit in memory consolidation occurring within hours of learning without a requirement for intervening sleep. (PsycINFO Database Record (c) 2015 APA, all rights reserved)

Developing a new test to identify consolidation-related memory markers of normal ageing and Alzheimer's Disease

Background: For newly encoded memories to be remembered, they must be consolidated. Research suggests that severe memory problems in AD are due, at least in part, to a fault in awake consolidation, which becomes increasingly vulnerable to interference from post-encoding sensory input. Importantly, post-encoding awake quiescence (quiet rest) strikingly reduces forgetting in AD because it provides conditions that are conducive to consolidation. However, it remains poorly understood how awake consolidation changes ‘normally’ with increasing age and how this differs from AD-related changes. The aim of this study was to develop a new test that can measure normal age-related and pathological AD-related changes in awake consolidation. Method: A new memory discrimination test was applied in healthy younger (N=40) and older (N=40) adults. Participants completed an incidental encoding task, where they were presented photos of everyday items, before experiencing a 10-minute delay condition of either (i) awake quiescence or (ii) ongoing sensory input. They then completed a visual memory discrimination test for the earlier presented photos. Older adults also completed a battery of neuropsychological measures. Result: Performance in the memory discrimination test was significantly poorer in older than younger adults. There was a significant main effect of delay condition because both younger and older adults who rested outperformed those who experienced ongoing sensory input. No significant interaction between age group and delay condition was observed. Conclusion: Despite age-related declines in memory performance, the magnitude of the consolidation interference effect was comparable in younger and older adults. This indicates that a stark increase in consolidation interference is unlikely to be accounted for by normal ageing and there is potential for consolidation interference to be used as a cognitive marker of AD

Comparable rest-related promotion of spatial memory consolidation in younger and older adults

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. Young and older adults learned a route through a virtual environment, followed by a 10-minute delay comprising either wakeful rest or a perceptual task, and a subsequent cognitive mapping task, requiring the pointing to landmarks from different locations. Pointing accuracy was lower in the older than younger adults. However, there was a comparable rest-related enhancement in pointing accuracy in the 2 age groups. Together our findings suggest that (1) the age-related decline in cognitive mapping cannot be explained by increased consolidation interference in older adults; and (2) as we grow older, rest continues to support the consolidation and integration of spatial memories

Lives without imagery:Congenital aphantasia

This is the author’s version of a work that was accepted for publication in Cortex. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published at doi:10.1016/j.cortex.2015.05.019

Macroparasites in Antarctic Penguins

Fil: Díaz, Julia Inés. Centro de Estudios en Parasitología y Vectores (CEPAVE). Facultad de Ciencias Naturales y Museo. Universidad Nacional de La Plata; ArgentinaFil: Fusaro, Bruno. Instituto Antártico Argentino (IIA); ArgentinaFil: Vidal, Virginia. Departamento de Ecología Evolutiva. Museo Nacional de Ciencias Naturales. CSIC. Madrid; EspañaFil: González-Acuña, Daniel. Facultad de Ciencias Veterinarias. Universidad de Concepción; UruguayFil: Schneider Costa, Erli. Universidade Estadual do Rio Grande do Sul ; BrazilFil: Dewar, Meagan. Deakin University; AustraliaFil: Gray, Rachael. Faculty of Veterinary Science. School of Life and Environmental Sciences. University of Sydney; AustraliaFil: Power, Michelle. Department of Biological Sciences. Macquarie University; AustraliaFil: Miller, Gary. Institute for Marine and Antarctic Studies. University of Tasmania; TasmaniaFil: Blyton, Michaela. Western Sydney University; AustraliaFil: Vanstreels, Ralph. Department of Pathology. Faculty of Veterinary Medicine and Animal Science. University of SÆo Paulo; BrazilFil: Barbosa, Andrés. Departamento de Ecología Evolutiva. Museo Nacional de Ciencias Naturales. CSIC. Madrid; Españ

Autobiographical thinking interferes with episodic memory consolidation

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.e. an 'internal' memory activity, also interferes with episodic memory consolidation. Participants were presented with three wordlists consisting of common nouns; one list was followed by wakeful rest, one by novel picture encoding and one by autobiographical retrieval/future imagination, cued by concrete sounds. Both novel encoding and autobiographical retrieval/future imagination lowered wordlist retention significantly. Follow-up experiments demonstrated that the interference by our cued autobiographical retrieval/future imagination delay condition could not be accounted for by the sound cues alone or by executive retrieval processes. Moreover, our results demonstrated evidence of a temporal gradient of interference across experiments. Thus, we propose that rich autobiographical retrieval/future imagination hampers the consolidation of recently acquired episodic memories and that such interference is particularly likely in the presence of external concrete cues