scholarly journals Time-dependent mnemonic vulnerability induced by new-learning

2018 ◽  
Author(s):  
Fengtao Shen ◽  
Yixuan Ku ◽  
Jue Wu ◽  
Yue Cui ◽  
Jianqi Li ◽  
...  
Keyword(s):  
Time Window ◽  
Inferior Frontal Gyrus ◽  
Pharmacological Intervention ◽  
Unstable State ◽  
Clinical Practices ◽  
Theoretical Understanding ◽  
Effective Strategies ◽  
Memory Integration ◽  
New Learning ◽  
Face Location

AbstractReactivation renders consolidated memory labile again, and the ensuing temporary reconsolidation process is highly susceptible to mnemonic modification. Here, we show that memories in such an unstable state could be reprogrammed by sheer behavioral means, bypassing the need for pharmacological intervention. In two experiments using a “face-location associationc” paradigm in which participants experienced a “Learning – New-learning – Final-test” programme, we demonstrate that reactivated memory traces were robustly hampered when the new learning was strategically administered within a critical 20-minute time window. Using fMRI, we further advance our theoretical understanding that this lability can be mechanistically explained by the differential activation in the hippocampal-amygdala memory system implicated by the new-learning whereas the mnemonic intrusion caused by newly learned memories is efficaciously reconciled by the left inferior frontal gyrus. Our findings provide important implications for educational and clinical practices in devising effective strategies for memory integration.

scholarly journals The Current Challenges for Drug Discovery in CNS Remyelination

2021 ◽  
Vol 22 (6) ◽  
pp. 2891
Author(s):  
Sonia Balestri ◽  
Alice Del Giovane ◽  
Carola Sposato ◽  
Marta Ferrarelli ◽  
Antonella Ragnini-Wilson
Keyword(s):  
Drug Screening ◽  
Myelin Sheath ◽  
Time Window ◽  
In Vitro Models ◽  
Adult Brain ◽  
Pharmacological Intervention ◽  
Cellular Models ◽  
New Findings ◽  
Myelin Injury

The myelin sheath wraps around axons, allowing saltatory currents to be transmitted along neurons. Several genetic, viral, or environmental factors can damage the central nervous system (CNS) myelin sheath during life. Unless the myelin sheath is repaired, these insults will lead to neurodegeneration. Remyelination occurs spontaneously upon myelin injury in healthy individuals but can fail in several demyelination pathologies or as a consequence of aging. Thus, pharmacological intervention that promotes CNS remyelination could have a major impact on patient’s lives by delaying or even preventing neurodegeneration. Drugs promoting CNS remyelination in animal models have been identified recently, mostly as a result of repurposing phenotypical screening campaigns that used novel oligodendrocyte cellular models. Although none of these have as yet arrived in the clinic, promising candidates are on the way. Many questions remain. Among the most relevant is the question if there is a time window when remyelination drugs should be administrated and why adult remyelination fails in many neurodegenerative pathologies. Moreover, a significant challenge in the field is how to reconstitute the oligodendrocyte/axon interaction environment representative of healthy as well as disease microenvironments in drug screening campaigns, so that drugs can be screened in the most appropriate disease-relevant conditions. Here we will provide an overview of how the field of in vitro models developed over recent years and recent biological findings about how oligodendrocytes mature after reactivation of their staminal niche. These data have posed novel questions and opened new views about how the adult brain is repaired after myelin injury and we will discuss how these new findings might change future drug screening campaigns for CNS regenerative drugs.

scholarly journals Overnight memory consolidation facilitates rather than interferes with new learning of similar materials - a study probing NMDA-receptors

2017 ◽  
Author(s):  
Asfestani M Alizadeh ◽  
E Braganza ◽  
J Schwidetzky ◽  
J Santiago ◽  
S Soekadar ◽  
...  
Keyword(s):  
Memory Consolidation ◽  
Time Dependent ◽  
Similar Material ◽  
Double Blind ◽  
Memory Integration ◽  
New Learning ◽  
Similar Materials ◽  
Cue Words ◽  
Enhanced Learning ◽  
Healthy Participants

AbstractWhereas sleep-dependent consolidation and its neurochemical underpinnings have been strongly researched, less is known about how consolidation during sleep affects subsequent learning. Since sleep enhances memory, it can be expected to pro-actively interfere with learning after sleep, in particular of similar materials. This pro-active interference should be enhanced by substances that benefit consolidation during sleep, such as D-cycloserine. We tested this hypothesis in two groups (Sleep, Wake) of young healthy participants receiving on one occasion D-cycloserine (175 mg) and on another occasion placebo, according to a double-blind balanced cross-over design. Treatment was administered after participants had learned a set of word-pairs (A-B list) and before nocturnal retention periods of sleep vs. wakefulness. After D-cycloserine blood plasma levels had dropped to negligible amounts, i.e., the next day in the evening, participants learned, in three sequential runs, new sets of word-pairs. One list – to enhance interference – consisted of the same cue words as the original set paired with a new target word (A-C list) and the other of completely new cue words (D-E set). Unexpectedly, during post-retention learning the A-C interference list was generally better learned than the completely new D-E list, which suggests that consolidation of previously encoded similar material enhances memory integration rather than pro-active interference. Consistent with this view, new learning of word-pairs was better after sleep than wakefulness. Similarly, D-cycloserine generally enhanced learning of new word-pairs, compared to placebo. This effect being independent of sleep or wakefulness, leads us to speculate that D-cycloserine, in addition to enhancing sleep-dependent consolidation, might mediate a time-dependent process of active forgetting.

scholarly journals Spatiotemporal Dynamics of Morphological Processing in Visual Word Recognition

2016 ◽  
Vol 28 (8) ◽  
pp. 1228-1242 ◽  
Author(s):  
Eddy Cavalli ◽  
Pascale Colé ◽  
Jean-Michel Badier ◽  
Christelle Zielinski ◽  
Valérie Chanoine ◽  
...  
Keyword(s):  
Semantic Processing ◽  
Time Course ◽  
Time Window ◽  
Inferior Frontal Gyrus ◽  
Superior Temporal Gyrus ◽  
Specific Area ◽  
Spatiotemporal Dynamics ◽  
Morphological Processing ◽  
Decision Task ◽  
Morphological Priming

The spatiotemporal dynamics of morphological, orthographic, and semantic processing were investigated in a primed lexical decision task in French using magnetoencephalography (MEG). The goal was to investigate orthographic and semantic contributions to morphological priming and compare these effects with pure orthographic and semantic priming. The time course of these effects was analyzed in anatomically defined ROIs that were selected according to previous MEG and fMRI findings. The results showed that morphological processing was not localized in one specific area but distributed over a vast network that involved left inferior temporal gyrus, left superior temporal gyrus, left inferior frontal gyrus, and left orbitofrontal gyrus. Second, all morphological effects were specific, that is, in none of the ROIs could morphology effects be explained by pure orthographic or pure semantic overlap. Third, the ventral route was sensitive to both the orthographic and semantic “part” of the morphological priming effect in the M350 time window. Fourth, the earliest effects of morphology occurred in left superior temporal gyrus around 250 msec and reflected the semantic contribution to morphological facilitation. Together then, the present results show that morphological processing is not just an emergent property of processing form or meaning and that semantic contributions to morphological facilitation can occur as early as 250 msec in the left superior temporal gyrus.

Understanding Asperger's Syndrome: Four New Titles

2001 ◽  
Vol 7 (4) ◽  
pp. 529-530
Author(s):  
N.R. Bryant
Keyword(s):  
Asperger's Syndrome ◽  
Asperger’S Syndrome ◽  
High Functioning Autism ◽  
Neuropsychological Functioning ◽  
Treatment Options ◽  
Diagnostic Category ◽  
Pharmacological Intervention ◽  
Diagnostic Process ◽  
Clinical Practices ◽  
Schizoid Personality Disorder

Asperger's Syndrome, edited by Ami Klin and colleagues of the Yale University Child Study Center, contains contributions from 27 authors representing 13 universities, and several agencies and clinical practices in the United Kingdom, Canada, and the USA. This is a thorough and sorely needed review of the research, diagnostic process, treatment options, and outcomes associated with Asperger's syndrome (AS). Written for professionals, the volume is research-based, and in this relatively new field of study, is as useful in elucidating the questions still requiring investigation as in describing what is currently known. Several aspects of diagnosis are covered, including the development of AS as a formal diagnostic category, a review of clinical features and associated conditions, differential diagnostic considerations (particularly high functioning Autism, Schizoid Personality Disorder, developmental language disorders, and Nonverbal Learning Disability), and special consideration of the contributions of motor functioning, social language use, and neuropsychological functioning to differential diagnosis. Of special interest to neuropsychologists may be the chapter reviewing neuropsychological and neuroimaging studies of AS, from which inferences can be drawn about potential neurodevelopmental processes leading to the manifestations of this disorder. Other chapters focus on genetic factors, clinical outcomes in adolescence and adulthood, pharmacological intervention, and general treatment considerations. A chapter on assessment suggests practical guidelines for assessment of cognitive, neuropsychological, communicative, social–emotional, and adaptive functioning. A set of essays by parents closes the volume, providing an important reconnection to the everyday challenges faced by individuals with AS and their families.

scholarly journals Post-reactivation new learning impairs and updates human episodic memory through dissociable processes

2018 ◽  
Author(s):  
Zijian Zhu ◽  
Yingying Wang ◽  
Jianrong Jia ◽  
Liqiang Huang ◽  
Yi Rao ◽  
...  
Keyword(s):  
Episodic Memory ◽  
Time Window ◽  
Alpha Power ◽  
New Information ◽  
New Learning ◽  
Power Change ◽  
Significant Impairment ◽  
Integration Effect ◽  
Inhibition Ability ◽  
Target Memory

AbstractLearning of competing information after reactivation has the potential to disrupt memory reconsolidation and thus impair a consolidated memory. Yet this effect has rarely been detected in episodic memory. By introducing an additional retrieving cue to the target memory, the current study detected significant impairment on the reactivated episodic memory, in addition to an integration of new information to the old memory. However, while the integration effect followed the time window of reconsolidation disruption, the impairment effect did not. MEG measurements further revealed alpha power change during reactivation and post-reactivation learning which showed different correlation patterns with the integration and impairment effects, confirming that the two effects relied on different processes. Therefore, post-reactivation new learning disrupts episodic memory but not through reconsolidation disruption. Further findings that the impairment effect was correlated with participants’ voluntary inhibition ability suggest an inhibition-based memory updating process underlying post-reactivation new learning.

scholarly journals Distinct roles for the Anterior Temporal Lobe and Angular Gyrus in the spatio-temporal cortical semantic network

2019 ◽  
Author(s):  
Seyedeh-Rezvan Farahibozorg ◽  
Richard N. Henson ◽  
Anna M. Woollams ◽  
Olaf Hauk
Keyword(s):  
Functional Connectivity ◽  
Temporal Lobe ◽  
Time Window ◽  
Inferior Frontal Gyrus ◽  
Semantic Knowledge ◽  
Angular Gyrus ◽  
Anterior Temporal Lobe ◽  
Sensory Motor ◽  
Semantic Variables ◽  
Spatio Temporal

AbstractIt is now well recognised that human semantic knowledge is supported by a large neural network distributed over multiple brain regions, but the dynamic organisation of this network remains unknown. Some studies have proposed that a central semantic hub coordinates this network. We explored the possibility of different types of semantic hubs; namely “representational hubs”, whose neural activity is modulated by semantic variables, and “connectivity hubs”, whose connectivity to distributed areas is modulated by semantic variables. We utilised the spatio-temporal resolution of source-estimated Electro-/Magnetoencephalography data in a word-concreteness task (17 participants, 12 female) in order to: (i) find representational hubs at different timepoints based on semantic modulation of evoked brain activity in source space; (ii) identify connectivity hubs among left Anterior Temporal Lobe (ATL), Angular Gyrus (AG), Middle Temporal Gyrus and Inferior Frontal Gyrus based on their functional connectivity to the whole cortex, in particular sensory-motor-limbic systems; and (iii) explicitly compare network models with and without an intermediate hub linking sensory input to other candidate hub regions using Dynamic Causal Modelling (DCM) of evoked responses. ATL’s activity was modulated as early as 150ms post-stimulus, while both ATL and AG showed modulations of functional connectivity with sensory-motor-limbic areas from 150-450ms. DCM favoured models with one intermediate hub, namely ATL in an early time window and AG in a later time-window. Our results support ATL as a single representational hub with an early onset, but suggest that both ATL and AG function as connectivity hubs depending on the stage of semantic processing.

scholarly journals Modeling Workplace Incivility as a Social Process Towards Sustainable Workforce in the Malaysian Context

2021 ◽  
Vol 16 (1) ◽  
pp. 175-182
Author(s):  
S.K. Musairah ◽  
Sabiroh Md Sabri ◽  
Anis Farhana
Keyword(s):  
Organizational Performance ◽  
Social Process ◽  
Well Being ◽  
Workplace Incivility ◽  
Integrative Model ◽  
Theoretical Understanding ◽  
Effective Strategies ◽  
The Social ◽  
The Future ◽  
And Behavior

Twenty years since the concept of workplace incivility has been introduced, research has been conducted in a variety of directions. While the literature has been expanding and it has been reported that as many as 96% employees have experienced workplace incivility and 99% have seen it, we still do not know how employees interpret of workplace incivility. Given that such an interpretation of the social process can affect the future thought and behavior of people, this information is important to understand workplace incivility beyond behavioral description. Although we have a comprehensive conceptual understanding of workplace incivility, without understanding the employees’ beliefs about incivility, we cannot effectively develop an integrative model of workplace incivility. The aim of this study is to develop a model on workplace incivility as a social process that includes interaction during and after the occurrence of incivility at the workplace. In addition, this research also aims to create awareness about workplace incivility; as well as employees’ preferences on how to address incivility at work and who should handle it. This qualitative study will investigate workplace incivility to understand incivility from the perspective of employees, refine the theoretical understanding of workplace incivility construct, and collecting data to develop the integrative model of workplace incivility. Employees will be asked to answer open-ended survey questions about the characteristics of workplace incivility and questions about why it happens. Responses will be analyzed with the phenomenological method. This research can also ease the development of practical strategies to manage and prevent workplace incivility. Therefore, the findings of this study can serve as a basis for specific prevention and intervention techniques that can be built in the future. This is because, it is important to uncover effective strategies to manage workplace incivility to improve employee well-being, which in turn would influence organizational performance.

Dissociated Σ=27 boundaries in silicon

1988 ◽  
Vol 46 ◽  
pp. 624-625
Author(s):  
A. Garg ◽  
W.A.T. Clark ◽  
J.P. Hirth
Keyword(s):  
Electron Diffraction ◽  
Local Minimum ◽  
Boundary Energy ◽  
Coincidence Site Lattice ◽  
Boundary Plane ◽  
Low Energy ◽  
Theoretical Understanding ◽  
Site Lattice ◽  
Kikuchi Pattern ◽  
Analysis Techniques

In the last twenty years, a significant amount of work has been done in the theoretical understanding of grain boundaries. The various proposed grain boundary models suggest the existence of coincidence site lattice (CSL) boundaries at specific misorientations where a periodic structure representing a local minimum of energy exists between the two crystals. In general, the boundary energy depends not only upon the density of CSL sites but also upon the boundary plane, so that different facets of the same boundary have different energy. Here we describe TEM observations of the dissociation of a Σ=27 boundary in silicon in order to reduce its surface energy and attain a low energy configuration.The boundary was identified as near CSL Σ=27 {255} having a misorientation of (38.7±0.2)°/[011] by standard Kikuchi pattern, electron diffraction and trace analysis techniques. Although the boundary appeared planar, in the TEM it was found to be dissociated in some regions into a Σ=3 {111} and a Σ=9 {122} boundary, as shown in Fig. 1.

When Hearing Does Not Mean Understanding: On the Neural Processing of Syntactically Complex Sentences by Listeners With Hearing Loss

2021 ◽  
pp. 1-13
Author(s):  
Margreet Vogelzang ◽  
Christiane M. Thiel ◽  
Stephanie Rosemann ◽  
Jochem W. Rieger ◽  
Esther Ruigendijk
Keyword(s):  
Hearing Loss ◽  
Sentence Processing ◽  
Secondary Task ◽  
Sentence Comprehension ◽  
Inferior Frontal Gyrus ◽  
Normal Hearing ◽  
Cognitive Demands ◽  
Sentence Complexity ◽  
Complex Sentences ◽  
And Task

Purpose Adults with mild-to-moderate age-related hearing loss typically exhibit issues with speech understanding, but their processing of syntactically complex sentences is not well understood. We test the hypothesis that listeners with hearing loss' difficulties with comprehension and processing of syntactically complex sentences are due to the processing of degraded input interfering with the successful processing of complex sentences. Method We performed a neuroimaging study with a sentence comprehension task, varying sentence complexity (through subject–object order and verb–arguments order) and cognitive demands (presence or absence of a secondary task) within subjects. Groups of older subjects with hearing loss ( n = 20) and age-matched normal-hearing controls ( n = 20) were tested. Results The comprehension data show effects of syntactic complexity and hearing ability, with normal-hearing controls outperforming listeners with hearing loss, seemingly more so on syntactically complex sentences. The secondary task did not influence off-line comprehension. The imaging data show effects of group, sentence complexity, and task, with listeners with hearing loss showing decreased activation in typical speech processing areas, such as the inferior frontal gyrus and superior temporal gyrus. No interactions between group, sentence complexity, and task were found in the neuroimaging data. Conclusions The results suggest that listeners with hearing loss process speech differently from their normal-hearing peers, possibly due to the increased demands of processing degraded auditory input. Increased cognitive demands by means of a secondary visual shape processing task influence neural sentence processing, but no evidence was found that it does so in a different way for listeners with hearing loss and normal-hearing listeners.

Evidence-Based Practice & Practice-Based Evidence Applied to Adult, Medical Speech-Language Pathology

2013 ◽  
Vol 18 (1) ◽  
pp. 14-26 ◽  
Author(s):  
Rik Lemoncello ◽  
Bryan Ness
Keyword(s):  
Evidence Based Practice ◽  
Single Case ◽  
Quality Data ◽  
Evidence Based ◽  
Speech Language Pathology ◽  
Clinical Practices ◽  
High Quality ◽  
Randomized Controlled Clinical Trials ◽  
Relative Paucity ◽  
Language Pathology

In this paper, we review concepts of evidence-based practice (EBP), and provide a discussion of the current limitations of EBP in terms of a relative paucity of efficacy evidence and the limitations of applying findings from randomized controlled clinical trials to individual clinical decisions. We will offer a complementary model of practice-based evidence (PBE) to encourage clinical scientists to design, implement, and evaluate our own clinical practices with high-quality evidence. We will describe two models for conducting PBE: the multiple baseline single-case experimental design and a clinical case study enhanced with generalization and control data probes. Gathering, analyzing, and sharing high-quality data can offer additional support through PBE to support EBP in speech-language pathology. It is our hope that these EBP and PBE strategies will empower clinical scientists to persevere in the quest for best practices.

Sign in / Sign up

Export Citation Format

Share Document