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remote memory [keywords]
- Modality-specific Alpha Modulations Facilitate Long-term Memory Encoding in the Presence of Distracters. [JOURNAL ARTICLE]
- J Cogn Neurosci 2014 Sep 22.:1-10.
It has been proposed that long-term memory encoding is not only dependent on engaging task-relevant regions but also on disengaging task-irrelevant regions. In particular, oscillatory alpha activity has been shown to be involved in shaping the functional architecture of the working brain because it reflects the functional disengagement of specific regions in attention and memory tasks. We here ask if such allocation of resources by alpha oscillations generalizes to long-term memory encoding in a cross-modal setting in which we acquired the ongoing brain activity using magnetoencephalography. Participants were asked to encode pictures while ignoring simultaneously presented words and vice versa. We quantified the brain activity during rehearsal reflecting subsequent memory in the different attention conditions. The key finding was that successful long-term memory encoding is reflected by alpha power decreases in the sensory region of the to-be-attended modality and increases in the sensory region of the to-be-ignored modality to suppress distraction during rehearsal period. Our results corroborate related findings from attention studies by demonstrating that alpha activity is also important for the allocation of resources during long-term memory encoding in the presence of distracters.
- Evidence for two distinct sleep-related long-term memory consolidation processes. [JOURNAL ARTICLE]
- Cortex 2014 Aug 28.:68-78.
Numerous studies examine the effect of a night's sleep on memory consolidation, but few go beyond this short time-scale to test long-lasting effects of sleep on memory. We investigated long-term effects of sleep on typical memory tasks. During the hours following learning, participants slept or stayed awake. We compared recall performance between wake and sleep conditions after delays of up to 6 days. Performance develops in two distinct ways. Word pair, syllable, and motor sequence learning tasks benefit from sleep during the first day after encoding, when compared with daytime or nighttime wakefulness. However, performance in the wake conditions recovers after another night of sleep, so that we observe no lasting effect of sleep. Sleep deprivation before recall does not impair performance. Thus, fatigue cannot adequately explain the lack of long-term effects. We suggest that the hippocampus might serve as a buffer during the retention interval, and consolidation occurs during delayed sleep. In contrast, a non-hippocampal mirror-tracing task benefits significantly from sleep, even when tested after a 4-day delay including recovery sleep. This indicates a dissociation between two sleep-related consolidation mechanisms, which could rely on distinct neuronal processes.
- Effects of cognitive training in Parkinson's disease: A randomized controlled trial. [JOURNAL ARTICLE]
- Parkinsonism Relat Disord 2014 Sep 16.
In Parkinson's Disease (PD), cognitive dysfunctions which can reduce patients' quality of life occur frequently. Data on non-pharmacological intervention effects on cognitive functions in patients with PD are rare. The aim of this study was to examine the effects of different cognitive group trainings (structured vs. unstructured) on cognition, depression, and quality of life in non-demented PD patients.In this randomized controlled trial, 65 non-demented patients with PD according to UK Brain Bank criteria (Hoehn & Yahr I-III) were allocated to one of two cognitive cognitive multi-component treatments ("NEUROvitalis", a structured training, or the unstructured training "Mentally fit" with randomly assembled cognitive tasks, each including 12 group-sessions à 90 min over 6 weeks) or a waiting list control group (CG). A neuropsychological test battery was performed before and after the training.Compared to the CG, patients from the "NEUROvitalis" group improved in short-term memory (word list learning "Memo": p < .01) and working memory (digit span from "DemTect": p < .05), whereas depression scores where reduced in the "Mentally fit" group (Becks Depression Inventory-II: p < .05). The "NEUROvitalis" group improved significantly more in working memory than the "Mentally fit" group (DemTect: p < .05).Cognitive and affective functions can be improved by cognitive trainings in PD patients. Specific effects (e.g. on memory and working memory versus depression) seem to be dependent on the type of training. Further research is needed to define long-term effects and the efficacy in PD patients with different extent of cognitive and neuropsychiatric symptoms.
- Effect of long-term outdoor air pollution and noise on cognitive and psychological functions in adults. [JOURNAL ARTICLE]
- Int J Hyg Environ Health 2014 Sep 3.
It has been hypothesized that air pollution and ambient noise might impact neurocognitive function. Early studies mostly investigated the associations of air pollution and ambient noise exposure with cognitive development in children. More recently, several studies investigating associations with neurocognitive function, mood disorders, and neurodegenerative disease in adult populations were published, yielding inconsistent results. The purpose of this review is to summarize the current evidence on air pollution and noise effects on mental health in adults. We included studies in adult populations (≥18 years old) published in English language in peer-reviewed journals. Fifteen articles related to long-term effects of air pollution and eight articles on long-term effects of ambient noise were extracted. Both exposures were separately shown to be associated with one or several measures of global cognitive function, verbal and nonverbal learning and memory, activities of daily living, depressive symptoms, elevated anxiety, and nuisance. No study considered both exposures simultaneously and few studies investigated progression of neurocognitive decline or psychological factors. The existing evidence generally supports associations of environmental factors with mental health, but does not suffice for an overall conclusion about the independent effect of air pollution and noise. There is a need for studies investigating simultaneously air pollution and noise exposures in association mental health, for longitudinal studies to corroborate findings from cross-sectional analyses, and for parallel toxicological and epidemiological studies to elucidate mechanisms and pathways of action.
- Distinct neurobehavioral dysfunction based on the timing of developmental binge-like alcohol exposure. [JOURNAL ARTICLE]
- Neuroscience 2014 Sep 17.
Gestational exposure to alcohol can result in long-lasting behavioral deficiencies generally described as fetal alcohol spectrum disorder (FASD). FASD-modeled rodent studies of acute ethanol exposure typically select one developmental window to simulate a specific context equivalent of human embryogenesis, and study consequences of ethanol exposure within that particular developmental epoch. Exposure timing is likely a large determinant in the neurobehavioral consequence of early ethanol exposure, as each brain region is variably susceptible to ethanol cytotoxicity and has unique sensitive periods in their development. We made a parallel comparison of the long-term effects of single-day binge ethanol at either embryonic day 8 (E8) or postnatal day 7 (P7) in male and female mice, and here demonstrate the differential long-term impacts on neuroanatomy, behavior and in vivo electrophysiology of two systems with very different developmental trajectories. The significant long-term differences in odor-evoked activity, local circuit inhibition, and spontaneous coherence between brain regions in the olfacto-hippocampal pathway that were found as a result of developmental ethanol exposure, varied based on insult timing. Long-term effects on cell proliferation and interneuron cell density were also found to vary by insult timing as well as by region. Finally, spatial memory performance and object exploration were affected in P7-exposed mice, but not E8-exposed mice. Our physiology and behavioral results are conceptually coherent with the neuroanatomical data attained from these same mice. Our results recognize both variable and shared effects of ethanol exposure timing on long-term circuit function and their supported behavior.
- Exposure to nicotine during pregnancy and altered learning and memory in the rat offspring. [JOURNAL ARTICLE]
- Nicotine Tob Res 2014 Sep 19.
Prenatal exposure to nicotine can cause many fetal developmental problems. This study determined the influence of nicotine during pregnancy on the development of cognitive behavior in the offspring.Nicotine was administered to pregnant rats through implanted osmotic mini-pumps at 6mg/kg/day and flow rate of 60μL/day for whole pregnancy from gestational day 4. Fetal and offspring body and brain weight was measured. Learning and memory were tested in adult offspring with Morris water maze; Learning and memory-related receptors were measured.The results showed that exposure to prenatal nicotine (PN) not only caused fetal growth restriction, but also had long-term effects on learning and memory in the offspring. The PN offspring exhibited longer escape latency regardless of sex. The number of passing the platform was significantly less in the PN offspring than that of the control. The expression of mRNA and protein of N-methyl-D-aspartic acid receptor (NMDAR) in the hippocampus was significantly increased, whereas alpha7 nicotinic acetylcholine receptor (α7 nAChR) protein was decreased with unchanged α7 nAChR mRNA in the PN offspring.The data provided novel information on the PN-affected development in learning and memory in the offspring, suggesting that α7 nAChR and NMDAR1 in the hippocampus might be the targets for actions of PN in association with memory impairment.
- Synaptic Plasticity and Memory: New Insights from Hippocampal Left-Right Asymmetries. [REVIEW]
- Neuroscientist 2014 Sep 19.
All synapses are not the same. They differ in their morphology, molecular constituents, and malleability. A striking left-right asymmetry in the distribution of different types of synapse was recently uncovered at the CA3-CA1 projection in the mouse hippocampus, whereby afferents from the CA3 in the left hemisphere innervate small, highly plastic synapses on the apical dendrites of CA1 pyramidal neurons, whereas those originating from the right CA3 target larger, more stable synapses. Activity-dependent modification of these synapses is thought to participate in circuit formation and remodeling during development, and further plastic changes may support memory encoding in adulthood. Therefore, exploiting the CA3-CA1 asymmetry provides a promising opportunity to investigate the roles that different types of synapse play in these fundamental properties of the CNS. Here we describe the discovery of these segregated synaptic populations in the mouse hippocampus, and discuss what we have already learnt about synaptic plasticity from this asymmetric arrangement. We then propose models for how the asymmetry could be generated during development, and how the adult hippocampus might use these distinct populations of synapses differentially during learning and memory. Finally, we outline the potential implications of this left-right asymmetry for human hippocampal function, as well as dysfunction in memory disorders such as Alzheimer's disease.
- Memory Banking: A Life Story Intervention for Aging Preparation and Mental Health Promotion. [JOURNAL ARTICLE]
- J Aging Health 2014 Sep 19.
The aim of this study is to examine the feasibility of Memory Banking (MB), a life story development intervention within the context of aging preparation. Individuals participate in MB to strategically document and share their life story, including mapping out future dreams, aspirations, plans, and decisions.Data (2010-2012) from eight MB workshops were examined to determine the impact of the intervention on mental health, social support, and quality of life.Recruitment efforts resulted in n = 72 participants, primarily female (72%), White/Caucasian (93%), average age of 70 years. Data indicated intervention effects showing improvements in depression (p = .041), mood disturbance (p = .0067), and cognitive performance (p = .0045).MB outcomes indicate that the intervention is promising and supports continued investigation and development in the area of life story development for aging preparation and improving late life mental health distress in a community setting. Future research is needed to examine the versatility and long-term effects of the MB intervention.
- Time course of motor and cognitive functions after chronic cerebral ischemia in rats. [JOURNAL ARTICLE]
- Behav Brain Res 2014 Sep 17.
Cerebral ischemia is one of the leading causes of death and long-term disability in aging populations, due to the frequent occurrence of irreversible brain damage and subsequent loss of neuronal function which lead to cognitive impairment and some motor dysfunction. In the present study, the real time course of motor and cognitive functions were evaluated following the chronic cerebral ischemia induced by permanent, bilateral occlusion of the common carotid arteries (PBOCCA). Male Sprague Dawley rats (200-300g) were subjected to PBOCCA or sham-operated surgery and tested 1, 2, 3 and 4 weeks following the ischemic insult. The results showed that PBOCCA significantly reduced step-through latency in a passive avoidance task at all time points when compared to the sham-operated group. PBOCCA rats also showed significant increase in escape latencies during training in the Morris water maze, as well as a reduction of the percentage of times spend in target quadrant of the maze at all time points following the occlusion. Importantly, there were no significant changes in locomotor activity between PBOCCA and sham-operated groups. The BDNF expression in the hippocampus was 29.3±3.1% and 40.1±2.6% on day 14 and 28 post PBOCCA, respectively compared to sham-operated group. Present data suggest that the PBOCCA procedure effectively induces behavioral, cognitive symptoms associated with cerebral ischemia and, consequently, provides a valuable model to study ischemia and related neurodegenerative disorder such as Alzheimer's disease and vascular dementia.
- Pharmacological blockage and P2X7 deletion hinder aversive memories: reversion in an enriched environment. [JOURNAL ARTICLE]
- Neuroscience 2014 Sep 16.
Adenosine triphosphate (ATP) plays a role in cell signaling. It was soon proposed that ATP activates ionotropic P2X receptors, exerting an influence on neurons as well as on glial cells. In addition to the fact that the activation of P2X and P2Y receptors can stimulate or inhibit the release of glutamate from rat hippocampal neurons, the release of ATP has been implicated in hippocampal long-term potentiation (LTP). Through different behavioral paradigms, this study aimed to investigate the participation of the P2X7R in genetically modified (KO) mice with the suppressed expression of this receptor and in the pharmacological blockage of this receptor in rats, as well as to evaluate the effect of environmental enrichment on potential mnemonic deficits. The results suggest that the P2X7R participates in both aversive and spatial memory processes: pharmacological blockage with the selective P2X7R antagonist, A-740003, in different time frames elicited dose-dependent impairments in memory acquisition, consolidation and retrieval in rats that were submitted to the contextual fear conditioning (FC) task, and the deletion of the P2X7R hampered and aversive memory processes of mice that were subjected to the FC paradigm. Experiments using mice that were subjected to environmental enrichment suggest that this form of stimulation reverses mnemonic impairments that are ascribed to the absence of the P2X7R, suggesting that these receptors do not participate on such a reversal. Finally, no alterations were observed in the habituation memory of P2X7KO mice.