Reconsolidation and extinction are dissociable and mutually exclusive processes: behavioral and molecular evidence.

PubMed

Merlo, Emiliano; Milton, Amy L; Goozée, Zara Y; Theobald, David E; Everitt, Barry J

2014-02-12

Memory persistence is critically influenced by retrieval. In rats, a single presentation of a conditioned fear stimulus induces memory reconsolidation and fear memory persistence, while repeated fear cue presentations result in loss of fear through extinction. These two opposite behavioral outcomes are operationally linked by the number of cue presentations at memory retrieval. However, the behavioral properties and mechanistic determinants of the transition have not yet been explored; in particular, whether reconsolidation and extinction processes coexist or are mutually exclusive, depending on the exposure to non-reinforced retrieval events. We characterized both behaviorally and molecularly the transition from reconsolidation to extinction of conditioned fear and showed that an increase in calcineurin (CaN) in the basolateral amygdala (BLA) supports the shift from fear maintenance to fear inhibition. Gradually increasing the extent of retrieval induces a gradual decrease in freezing responses to the conditioned stimulus and a gradual increase in amygdala CaN level. This newly synthesized CaN is required for the extinction, but not the reconsolidation, of conditioned fear. During the transition from reconsolidation to extinction, we have revealed an insensitive state of the fear memory where NMDA-type glutamate receptor agonist and antagonist drugs are unable either to modulate CaN levels in the BLA or alter the reconsolidation or extinction processes. Together, our data indicate both that reconsolidation and extinction are mutually exclusive processes and also reveal the presence of a transitional, or "limbo," state of the original memory between these two alternative outcomes of fear memory retrieval, when neither process is engaged.

Social memory engram in the hippocampus.

PubMed

Okuyama, Teruhiro

2018-04-01

Social memory is one of the crucial components of episodic memories. Gregarious animals living in societies utilize social memory to exhibit the appropriate social behaviors such as aggression, avoidance, cooperative behavior, and even mating behavior. However, the neural mechanisms underlying social memory in the hippocampus remains mysterious. Here, I review some evidence from work done in rodents and primates on the brain region(s) and circuits encoding and/or retrieving social memory, as well as a storage for social memory (i.e. social memory engram neurons). Based on our recent findings that neural ensemble in ventral CA1 sub-region of the hippocampus possesses social memory engram, I would discuss the neural network for social information processing in order to encode social memory; and its evolutionary conservation between rodents and human. Copyright © 2017 Elsevier Ireland Ltd and Japan Neuroscience Society. All rights reserved.

Memory and learning behaviors mimicked in nanogranular SiO2-based proton conductor gated oxide-based synaptic transistors

NASA Astrophysics Data System (ADS)

Wan, Chang Jin; Zhu, Li Qiang; Zhou, Ju Mei; Shi, Yi; Wan, Qing

2013-10-01

In neuroscience, signal processing, memory and learning function are established in the brain by modifying ionic fluxes in neurons and synapses. Emulation of memory and learning behaviors of biological systems by nanoscale ionic/electronic devices is highly desirable for building neuromorphic systems or even artificial neural networks. Here, novel artificial synapses based on junctionless oxide-based protonic/electronic hybrid transistors gated by nanogranular phosphorus-doped SiO2-based proton-conducting films are fabricated on glass substrates by a room-temperature process. Short-term memory (STM) and long-term memory (LTM) are mimicked by tuning the pulse gate voltage amplitude. The LTM process in such an artificial synapse is due to the proton-related interfacial electrochemical reaction. Our results are highly desirable for building future neuromorphic systems or even artificial networks via electronic elements.In neuroscience, signal processing, memory and learning function are established in the brain by modifying ionic fluxes in neurons and synapses. Emulation of memory and learning behaviors of biological systems by nanoscale ionic/electronic devices is highly desirable for building neuromorphic systems or even artificial neural networks. Here, novel artificial synapses based on junctionless oxide-based protonic/electronic hybrid transistors gated by nanogranular phosphorus-doped SiO2-based proton-conducting films are fabricated on glass substrates by a room-temperature process. Short-term memory (STM) and long-term memory (LTM) are mimicked by tuning the pulse gate voltage amplitude. The LTM process in such an artificial synapse is due to the proton-related interfacial electrochemical reaction. Our results are highly desirable for building future neuromorphic systems or even artificial networks via electronic elements. Electronic supplementary information (ESI) available. See DOI: 10.1039/c3nr02987e

Memory modification as an outcome variable in anxiety disorder treatment.

PubMed

Tryon, Warren W; McKay, Dean

2009-05-01

Learning and memory are interdependent processes. Memories are learned, and cumulative learning requires memory. It is generally accepted that learning contributes to psychopathology and consequently to pertinent memory formation. Neuroscience and psychological research have established that memory is an active reconstructive process that is influenced by thoughts, feelings, and behaviors including post-event information. Recent research on the treatment of anxiety disorders using medications (i.e., d-cyclcloserine) to alter neurological systems associated with memory used in conjunction with behavior therapy suggests that memory is part of a central mechanism in the etiology and maintenance of these conditions. The main thesis of this article is that learning-based interventions create new memories that may modify existing ones. This raises the possibility of using such memory modifications to measure intervention outcome. A connectionist context for understanding this phenomenon and informing intervention is provided, with specific reference to post-traumatic stress disorder, obsessive-compulsive disorder, and generalized anxiety disorder. Recommendations for future research examining the role of memory change in treatment outcome are suggested.

Perceptual chunking and its effect on memory in speech processing: ERP and behavioral evidence

PubMed Central

Gilbert, Annie C.; Boucher, Victor J.; Jemel, Boutheina

2014-01-01

We examined how perceptual chunks of varying size in utterances can influence immediate memory of heard items (monosyllabic words). Using behavioral measures and event-related potentials (N400) we evaluated the quality of the memory trace for targets taken from perceived temporal groups (TGs) of three and four items. Variations in the amplitude of the N400 showed a better memory trace for items presented in TGs of three compared to those in groups of four. Analyses of behavioral responses along with P300 components also revealed effects of chunk position in the utterance. This is the first study to measure the online effects of perceptual chunks on the memory trace of spoken items. Taken together, the N400 and P300 responses demonstrate that the perceptual chunking of speech facilitates information buffering and a processing on a chunk-by-chunk basis. PMID:24678304

Perceptual chunking and its effect on memory in speech processing: ERP and behavioral evidence.

PubMed

Gilbert, Annie C; Boucher, Victor J; Jemel, Boutheina

2014-01-01

We examined how perceptual chunks of varying size in utterances can influence immediate memory of heard items (monosyllabic words). Using behavioral measures and event-related potentials (N400) we evaluated the quality of the memory trace for targets taken from perceived temporal groups (TGs) of three and four items. Variations in the amplitude of the N400 showed a better memory trace for items presented in TGs of three compared to those in groups of four. Analyses of behavioral responses along with P300 components also revealed effects of chunk position in the utterance. This is the first study to measure the online effects of perceptual chunks on the memory trace of spoken items. Taken together, the N400 and P300 responses demonstrate that the perceptual chunking of speech facilitates information buffering and a processing on a chunk-by-chunk basis.

Epigenetic mechanisms in memory and synaptic function

PubMed Central

Sultan, Faraz A; Day, Jeremy J

2011-01-01

Although the term ‘epigenetics’ was coined nearly seventy years ago, its critical function in memory processing by the adult CNS has only recently been appreciated. The hypothesis that epigenetic mechanisms regulate memory and behavior was motivated by the need for stable molecular processes that evade turnover of the neuronal proteome. In this article, we discuss evidence that supports a role for neural epigenetic modifications in the formation, consolidation and storage of memory. In addition, we will review the evidence that epigenetic mechanisms regulate synaptic plasticity, a cellular correlate of memory. We will also examine how the concerted action of multiple epigenetic mechanisms with varying spatiotemporal profiles influence selective gene expression in response to behavioral experience. Finally, we will suggest key areas for future research that will help elucidate the complex, vital and still mysterious, role of epigenetic mechanisms in neural function and behavior. PMID:22122279

Memory lane and morality: how childhood memories promote prosocial behavior.

PubMed

Gino, Francesca; Desai, Sreedhari D

2012-04-01

Although research has established that autobiographical memory affects one's self-concept, little is known about how it affects moral behavior. We focus on a specific type of autobiographical memory: childhood memories. Drawing on research on memory and moral psychology, we propose that childhood memories elicit moral purity, which we define as a psychological state of feeling morally clean and innocent. In turn, heightened moral purity leads to greater prosocial behavior. In Experiment 1, participants instructed to recall childhood memories were more likely to help the experimenter with a supplementary task than were participants in a control condition, and this effect was mediated by moral purity. In Experiment 2, the same manipulation increased the amount of money participants donated to a good cause, and both implicit and explicit measures of moral purity mediated the effect. Experiment 3 provides further support for the process linking childhood memories and prosocial behavior through moderation. In Experiment 4, we found that childhood memories led to punishment of others' ethically questionable actions. Finally, in Experiment 5, both positively valenced and negatively valenced childhood memories increased helping compared to a control condition.

Double-Labeled Metabolic Maps of Memory.

ERIC Educational Resources Information Center

John, E. R.; And Others

1986-01-01

Reviews a study which sought to obtain a quantitative metabolic map of the neurons mediating a specific memory. Research results support notions of cooperative processes in which nonrandom behavior of high ensembles of neural elements mediates the integration and processing of information and the retrieval of memory. (ML)

Working Memory in the Service of Executive Control Functions.

PubMed

Mansouri, Farshad A; Rosa, Marcello G P; Atapour, Nafiseh

2015-01-01

Working memory is a type of short-term memory which has a crucial cognitive function that supports ongoing and upcoming behaviors, allowing storage of information across delay periods. The content of this memory may typically include tangible information about features such as the shape, color or texture of an object, and its location and motion relative to the body, as well as phonological information. The neural correlate of working memory has been found in different brain areas that are involved in organizing perceptual or motor functions. In particular, neuronal activity in prefrontal areas encodes task-related information corresponding to working memory across delay periods, and lesions in the prefrontal cortex severely affect the ability to retain this type of memory. Recent studies have further expanded the scope and possible role of working memory by showing that information of a more abstract nature (including a behavior-guiding rule, or the occurrence of a conflict in information processing) can also be maintained in short-term memory, and used for adjusting the allocation of executive control in dynamic environments. It has also been shown that neuronal activity in the prefrontal cortex encodes and maintains information about such abstract entities. These findings suggest that the prefrontal cortex plays crucial roles in the organization of goal-directed behavior by supporting many different mnemonic processes, which maintain a wide range of information required for the executive control of ongoing and upcoming behaviors.

The cortical basis of true memory and false memory for motion.

PubMed

Karanian, Jessica M; Slotnick, Scott D

2014-02-01

Behavioral evidence indicates that false memory, like true memory, can be rich in sensory detail. By contrast, there is fMRI evidence that true memory for visual information produces greater activity in earlier visual regions than false memory, which suggests true memory is associated with greater sensory detail. However, false memory in previous fMRI paradigms may have lacked sufficient sensory detail to recruit earlier visual processing regions. To investigate this possibility in the present fMRI study, we employed a paradigm that produced feature-specific false memory with a high degree of visual detail. During the encoding phase, moving or stationary abstract shapes were presented to the left or right of fixation. During the retrieval phase, shapes from encoding were presented at fixation and participants classified each item as previously "moving" or "stationary" within each visual field. Consistent with previous fMRI findings, true memory but not false memory for motion activated motion processing region MT+, while both true memory and false memory activated later cortical processing regions. In addition, false memory but not true memory for motion activated language processing regions. The present findings indicate that true memory activates earlier visual regions to a greater degree than false memory, even under conditions of detailed retrieval. Thus, the dissociation between previous behavioral findings and fMRI findings do not appear to be task dependent. Future work will be needed to assess whether the same pattern of true memory and false memory activity is observed for different sensory modalities. Copyright © 2013 Elsevier Ltd. All rights reserved.

Hippocampal brain-network coordination during volitional exploratory behavior enhances learning

PubMed Central

Voss, Joel L.; Gonsalves, Brian D.; Federmeier, Kara D.; Tranel, Daniel; Cohen, Neal J.

2010-01-01

Exploratory behaviors during learning determine what is studied and when, helping to optimize subsequent memory performance. We manipulated how much control subjects had over the position of a moving window through which they studied objects and their locations, in order to elucidate the cognitive and neural determinants of exploratory behaviors. Our behavioral, neuropsychological, and neuroimaging data indicate volitional control benefits memory performance, and is linked to a brain network centered on the hippocampus. Increases in correlated activity between the hippocampus and other areas were associated with specific aspects of memory, suggesting that volitional control optimizes interactions among specialized neural systems via the hippocampus. Memory is therefore an active process intrinsically linked to behavior. Furthermore, brain structures typically seen as passive participants in memory encoding (e.g., the hippocampus) are actually part of an active network that controls behavior dynamically as it unfolds. PMID:21102449

Hippocampal brain-network coordination during volitional exploratory behavior enhances learning.

PubMed

Voss, Joel L; Gonsalves, Brian D; Federmeier, Kara D; Tranel, Daniel; Cohen, Neal J

2011-01-01

Exploratory behaviors during learning determine what is studied and when, helping to optimize subsequent memory performance. To elucidate the cognitive and neural determinants of exploratory behaviors, we manipulated the control that human subjects had over the position of a moving window through which they studied objects and their locations. Our behavioral, neuropsychological and neuroimaging data indicate that volitional control benefits memory performance and is linked to a brain network that is centered on the hippocampus. Increases in correlated activity between the hippocampus and other areas were associated with specific aspects of memory, which suggests that volitional control optimizes interactions among specialized neural systems through the hippocampus. Memory is therefore an active process that is intrinsically linked to behavior. Furthermore, brain structures that are typically seen as passive participants in memory encoding (for example, the hippocampus) are actually part of an active network that controls behavior dynamically as it unfolds.

Processing Speed Predicts Behavioral Treatment Outcomes in Children with Attention-Deficit/Hyperactivity Disorder Predominantly Inattentive Type.

PubMed

Adalio, Christopher J; Owens, Elizabeth B; McBurnett, Keith; Hinshaw, Stephen P; Pfiffner, Linda J

2018-05-01

Neuropsychological functioning underlies behavioral symptoms of attention-deficit/hyperactivity disorder (ADHD). Children with all forms of ADHD are vulnerable to working memory deficits and children presenting with the inattentive form of ADHD (ADHD-I) appear particularly vulnerable to processing speed deficits. As ADHD-I is the most common form of ADHD presented by children in community settings, it is important to consider how treatment interventions for children with ADHD-I may be affected by deficits in processing speed and working memory. We utilize data collected from 199 children with ADHD-I, aged 7 to 11 years, who participated in a randomized clinical trial of a psychosocial-behavioral intervention. Our aims are first to determine whether processing speed or working memory predict treatment outcomes in ADHD-I symptom severity, and second whether they moderate treatment effects on ADHD-I symptom severity. Results of linear regression analyses reveal that baseline processing speed significantly predicts posttreatment ADHD-I symptom severity when controlling for baseline ADHD-I symptom severity, such that better processing speed is associated with greater symptom improvement. However, predictive effects of working memory and moderation effects of both working memory and processing speed are not supported in the present study. We discuss study limitations and implications of the relation between processing speed and treatment benefits from psychosocial treatments for children with ADHD-I.

Learning-performance distinction and memory processes for motor skills: a focused review and perspective.

PubMed

Kantak, Shailesh S; Winstein, Carolee J

2012-03-01

Behavioral research in cognitive psychology provides evidence for an important distinction between immediate performance that accompanies practice and long-term performance that reflects the relative permanence in the capability for the practiced skill (i.e. learning). This learning-performance distinction is strikingly evident when challenging practice conditions may impair practice performance, but enhance long-term retention of motor skills. A review of motor learning studies with a specific focus on comparing differences in performance between that at the end of practice and at delayed retention suggests that the delayed retention or transfer performance is a better indicator of motor learning than the performance at (or end of) practice. This provides objective evidence for the learning-performance distinction. This behavioral evidence coupled with an understanding of the motor memory processes of encoding, consolidation and retrieval may provide insight into the putative mechanism that implements the learning-performance distinction. Here, we propose a simplistic empirically-based framework--motor behavior-memory framework--that integrates the temporal evolution of motor memory processes with the time course of practice and delayed retention frequently used in behavioral motor learning paradigms. In the context of the proposed framework, recent research has used noninvasive brain stimulation to decipher the role of each motor memory process, and specific cortical brain regions engaged in motor performance and learning. Such findings provide beginning insights into the relationship between the time course of practice-induced performance changes and motor memory processes. This in turn has promising implications for future research and practical applications. Copyright © 2011 Elsevier B.V. All rights reserved.

Dopamine and extinction: A convergence of theory with fear and reward circuitry

PubMed Central

Abraham, Antony D.; Neve, Kim A.; Lattal, K. Matthew

2014-01-01

Research on dopamine lies at the intersection of sophisticated theoretical and neurobiological approaches to learning and memory. Dopamine has been shown to be critical for many processes that drive learning and memory, including motivation, prediction error, incentive salience, memory consolidation, and response output. Theories of dopamine’s function in these processes have, for the most part, been developed from behavioral approaches that examine learning mechanisms in reward-related tasks. A parallel and growing literature indicates that dopamine is involved in fear conditioning and extinction. These studies are consistent with long-standing ideas about appetitive-aversive interactions in learning theory and they speak to the general nature of cellular and molecular processes that underlie behavior. We review the behavioral and neurobiological literature showing a role for dopamine in fear conditioning and extinction. At a cellular level, we review dopamine signaling and receptor pharmacology, cellular and molecular events that follow dopamine receptor activation, and brain systems in which dopamine functions. At a behavioral level, we describe theories of learning and dopamine function that could describe the fundamental rules underlying how dopamine modulates different aspects of learning and memory processes. PMID:24269353

Dopamine and extinction: a convergence of theory with fear and reward circuitry.

PubMed

Abraham, Antony D; Neve, Kim A; Lattal, K Matthew

2014-02-01

Research on dopamine lies at the intersection of sophisticated theoretical and neurobiological approaches to learning and memory. Dopamine has been shown to be critical for many processes that drive learning and memory, including motivation, prediction error, incentive salience, memory consolidation, and response output. Theories of dopamine's function in these processes have, for the most part, been developed from behavioral approaches that examine learning mechanisms in reward-related tasks. A parallel and growing literature indicates that dopamine is involved in fear conditioning and extinction. These studies are consistent with long-standing ideas about appetitive-aversive interactions in learning theory and they speak to the general nature of cellular and molecular processes that underlie behavior. We review the behavioral and neurobiological literature showing a role for dopamine in fear conditioning and extinction. At a cellular level, we review dopamine signaling and receptor pharmacology, cellular and molecular events that follow dopamine receptor activation, and brain systems in which dopamine functions. At a behavioral level, we describe theories of learning and dopamine function that could describe the fundamental rules underlying how dopamine modulates different aspects of learning and memory processes. Copyright © 2013 Elsevier Inc. All rights reserved.

Working memory capacity and task goals modulate error-related ERPs.

PubMed

Coleman, James R; Watson, Jason M; Strayer, David L

2018-03-01

The present study investigated individual differences in information processing following errant behavior. Participants were initially classified as high or as low working memory capacity using the Operation Span Task. In a subsequent session, they then performed a high congruency version of the flanker task under both speed and accuracy stress. We recorded ERPs and behavioral measures of accuracy and response time in the flanker task with a primary focus on processing following an error. The error-related negativity was larger for the high working memory capacity group than for the low working memory capacity group. The positivity following an error (Pe) was modulated to a greater extent by speed-accuracy instruction for the high working memory capacity group than for the low working memory capacity group. These data help to explicate the neural bases of individual differences in working memory capacity and cognitive control. © 2017 Society for Psychophysiological Research.

Working memory and semantic involvement in sentence processing: a case of pure progressive amnesia.

PubMed

Fossard, Marion; Rigalleau, François; Puel, Michèle; Nespoulous, Jean-Luc; Viallard, Gérard; Démonet, Jean-François; Cardebat, Dominique

2006-01-01

ED, a 83-year-old woman, meets the criteria of pure progressive amnesia, with gradual impairment of episodic and autobiographical memory, sparing of semantic processing and strong working memory (WM) deficit. The dissociation between disturbed WM and spared semantic processing permitted testing the role of WM in processing anaphors like pronouns or repeated names. Results showed a globally normal anaphoric behavior in two experiments requiring anaphoric processing in sentence production and comprehension. We suggest that preserved semantic processing in ED would have compensated for working memory deficit in anaphoric processing.

Memory Effects on Movement Behavior in Animal Foraging

PubMed Central

Bracis, Chloe; Gurarie, Eliezer; Van Moorter, Bram; Goodwin, R. Andrew

2015-01-01

An individual’s choices are shaped by its experience, a fundamental property of behavior important to understanding complex processes. Learning and memory are observed across many taxa and can drive behaviors, including foraging behavior. To explore the conditions under which memory provides an advantage, we present a continuous-space, continuous-time model of animal movement that incorporates learning and memory. Using simulation models, we evaluate the benefit memory provides across several types of landscapes with variable-quality resources and compare the memory model within a nested hierarchy of simpler models (behavioral switching and random walk). We find that memory almost always leads to improved foraging success, but that this effect is most marked in landscapes containing sparse, contiguous patches of high-value resources that regenerate relatively fast and are located in an otherwise devoid landscape. In these cases, there is a large payoff for finding a resource patch, due to size, value, or locational difficulty. While memory-informed search is difficult to differentiate from other factors using solely movement data, our results suggest that disproportionate spatial use of higher value areas, higher consumption rates, and consumption variability all point to memory influencing the movement direction of animals in certain ecosystems. PMID:26288228

Memory Effects on Movement Behavior in Animal Foraging.

PubMed

Bracis, Chloe; Gurarie, Eliezer; Van Moorter, Bram; Goodwin, R Andrew

2015-01-01

An individual's choices are shaped by its experience, a fundamental property of behavior important to understanding complex processes. Learning and memory are observed across many taxa and can drive behaviors, including foraging behavior. To explore the conditions under which memory provides an advantage, we present a continuous-space, continuous-time model of animal movement that incorporates learning and memory. Using simulation models, we evaluate the benefit memory provides across several types of landscapes with variable-quality resources and compare the memory model within a nested hierarchy of simpler models (behavioral switching and random walk). We find that memory almost always leads to improved foraging success, but that this effect is most marked in landscapes containing sparse, contiguous patches of high-value resources that regenerate relatively fast and are located in an otherwise devoid landscape. In these cases, there is a large payoff for finding a resource patch, due to size, value, or locational difficulty. While memory-informed search is difficult to differentiate from other factors using solely movement data, our results suggest that disproportionate spatial use of higher value areas, higher consumption rates, and consumption variability all point to memory influencing the movement direction of animals in certain ecosystems.

Object-Location Memory: A Lesion-Behavior Mapping Study in Stroke Patients

ERIC Educational Resources Information Center

van Asselen, Marieke; Kessels, Roy P. C.; Frijns, Catharina J. M.; Kappelle, L. Jaap; Neggers, Sebastiaan F. W.; Postma, Albert

2009-01-01

Object-location memory is an important form of spatial memory, comprising different subcomponents that each process specific types of information within memory, i.e. remembering objects, remembering positions and binding these features in memory. In the current study we investigated the neural correlates of binding categorical (relative) or…

Role of the lateral habenula in memory through online processing of information.

PubMed

Mathis, Victor; Lecourtier, Lucas

2017-11-01

Our memory abilities, whether they involve short-term working memory or long-term episodic or procedural memories, are essential for our well-being, our capacity to adapt to constraints of our environment and survival. Therefore, several key brain regions and neurotransmitter systems are engaged in the processing of sensory information to either maintain such information in working memory so that it will quickly be used, and/or participate in the elaboration and storage of enduring traces useful for longer periods of time. Animal research has recently attracted attention on the lateral habenula which, as shown in rodents and non-human primates, seems to process information stemming in the main regions involved in memory processing, e.g., the medial prefrontal cortex, the hippocampus, the amygdala, the septal region, the basal ganglia, and participates in the control of key memory-related neurotransmitters systems, i.e., dopamine, serotonin, acetylcholine. Recently, the lateral habenula has been involved in working and spatial reference memories, in rodents, likely by participating in online processing of contextual information. In addition, several behavioral studies strongly suggest that it is also involved in the processing of the emotional valance of incoming information in order to adapt to particularly stressful situations. Therefore, the lateral habenula appears like a key region at the interface between cognition and emotion to participate in the selection of appropriate behaviors. Copyright © 2017 Elsevier Inc. All rights reserved.

Cholinergic modulation of cognitive processing: insights drawn from computational models

PubMed Central

Newman, Ehren L.; Gupta, Kishan; Climer, Jason R.; Monaghan, Caitlin K.; Hasselmo, Michael E.

2012-01-01

Acetylcholine plays an important role in cognitive function, as shown by pharmacological manipulations that impact working memory, attention, episodic memory, and spatial memory function. Acetylcholine also shows striking modulatory influences on the cellular physiology of hippocampal and cortical neurons. Modeling of neural circuits provides a framework for understanding how the cognitive functions may arise from the influence of acetylcholine on neural and network dynamics. We review the influences of cholinergic manipulations on behavioral performance in working memory, attention, episodic memory, and spatial memory tasks, the physiological effects of acetylcholine on neural and circuit dynamics, and the computational models that provide insight into the functional relationships between the physiology and behavior. Specifically, we discuss the important role of acetylcholine in governing mechanisms of active maintenance in working memory tasks and in regulating network dynamics important for effective processing of stimuli in attention and episodic memory tasks. We also propose that theta rhythm plays a crucial role as an intermediary between the physiological influences of acetylcholine and behavior in episodic and spatial memory tasks. We conclude with a synthesis of the existing modeling work and highlight future directions that are likely to be rewarding given the existing state of the literature for both empiricists and modelers. PMID:22707936

Unraveling the complexities of circadian and sleep interactions with memory formation through invertebrate research

PubMed Central

Michel, Maximilian; Lyons, Lisa C.

2014-01-01

Across phylogeny, the endogenous biological clock has been recognized as providing adaptive advantages to organisms through coordination of physiological and behavioral processes. Recent research has emphasized the role of circadian modulation of memory in generating peaks and troughs in cognitive performance. The circadian clock along with homeostatic processes also regulates sleep, which itself impacts the formation and consolidation of memory. Thus, the circadian clock, sleep and memory form a triad with ongoing dynamic interactions. With technological advances and the development of a global 24/7 society, understanding the mechanisms underlying these connections becomes pivotal for development of therapeutic treatments for memory disorders and to address issues in cognitive performance arising from non-traditional work schedules. Invertebrate models, such as Drosophila melanogaster and the mollusks Aplysia and Lymnaea, have proven invaluable tools for identification of highly conserved molecular processes in memory. Recent research from invertebrate systems has outlined the influence of sleep and the circadian clock upon synaptic plasticity. In this review, we discuss the effects of the circadian clock and sleep on memory formation in invertebrates drawing attention to the potential of in vivo and in vitro approaches that harness the power of simple invertebrate systems to correlate individual cellular processes with complex behaviors. In conclusion, this review highlights how studies in invertebrates with relatively simple nervous systems can provide mechanistic insights into corresponding behaviors in higher organisms and can be used to outline possible therapeutic options to guide further targeted inquiry. PMID:25136297

Post polymerization cure shape memory polymers

DOEpatents

Wilson, Thomas S.; Hearon, II, Michael Keith; Bearinger, Jane P.

2017-01-10

This invention relates to chemical polymer compositions, methods of synthesis, and fabrication methods for devices regarding polymers capable of displaying shape memory behavior (SMPs) and which can first be polymerized to a linear or branched polymeric structure, having thermoplastic properties, subsequently processed into a device through processes typical of polymer melts, solutions, and dispersions and then crossed linked to a shape memory thermoset polymer retaining the processed shape.

Post polymerization cure shape memory polymers

DOEpatents

Wilson, Thomas S; Hearon, Michael Keith; Bearinger, Jane P

2014-11-11

This invention relates to chemical polymer compositions, methods of synthesis, and fabrication methods for devices regarding polymers capable of displaying shape memory behavior (SMPs) and which can first be polymerized to a linear or branched polymeric structure, having thermoplastic properties, subsequently processed into a device through processes typical of polymer melts, solutions, and dispersions and then crossed linked to a shape memory thermoset polymer retaining the processed shape.

Encoding and choice in the task span paradigm.

PubMed

Reiman, Kaitlin M; Weaver, Starla M; Arrington, Catherine M

2015-03-01

Cognitive control during sequences of planned behaviors requires both plan-level processes such as generating, maintaining, and monitoring the plan, as well as task-level processes such as selecting, establishing and implementing specific task sets. The task span paradigm (Logan in J Exp Psychol Gen 133:218-236, 2004) combines two common cognitive control paradigms, task switching and working memory span, to investigate the integration of plan-level and task-level processes during control of sequential behavior. The current study expands past task span research to include measures of encoding processes and choice behavior with volitional sequence generation, using the standard task span as well as a novel voluntary task span paradigm. In two experiments, we consider how sequence complexity, defined separately for plan-level and task-level complexity, influences sequence encoding (Experiment 1), sequence choice (Experiment 2), sequence memory, and task performance of planned sequences of action. Results indicate that participants were sensitive to sequence complexity, but that different aspects of behavior are most strongly influenced by different types of complexity. Hierarchical complexity at the plan level best predicts voluntary sequence generation and memory; while switch frequency at the task level best predicts encoding of externally defined sequences and task performance. Furthermore, performance RTs were similar for externally and internally defined plans, whereas memory was improved for internally defined sequences. Finally, participants demonstrated a significant sequence choice bias in the voluntary task span. Consistent with past research on choice behavior, volitional selection of plans was markedly influenced by both the ease of memory and performance.

Differentiating location- and distance-based processes in memory for time: an ERP study.

PubMed

Curran, Tim; Friedman, William J

2003-09-01

Memory for the time of events may benefit from reconstructive, location-based, and distance-based processes, but these processes are difficult to dissociate with behavioral methods. Neuropsychological research has emphasized the contribution of prefrontal brain mechanisms to memory for time but has not clearly differentiated location- from distance-based processing. The present experiment recorded event-related brain potentials (ERPs) while subjects completed two different temporal memory tests, designed to emphasize either location- or distance-based processing. The subjects' reports of location-based versus distance-based strategies and the reaction time pattern validated our experimental manipulation. Late (800-1,800 msec) frontal ERP effects were related to location-based processing. The results provide support for a two-process theory of memory for time and suggest that frontal memory mechanisms are specifically related to reconstructive, location-based processing.

Cue-independent memory impairment by reactivation-coupled interference in human declarative memory.

PubMed

Zhu, Zijian; Wang, Yingying; Cao, Zhijun; Chen, Biqing; Cai, Huaqian; Wu, Yanhong; Rao, Yi

2016-10-01

Memory is a dynamic process. While memory becomes increasingly resistant to interference after consolidation, a brief reactivation renders it unstable again. Previous studies have shown that interference, when applied upon reactivation, impairs the consolidated memory, presumably by disrupting the reconsolidation of the memory. However, attempts have failed in disrupting human declarative memory, raising a question about whether declarative memory becomes unstable upon reactivation. Here, we used a double-cue/one-target paradigm, which associated the same target with two different cues in initial memory formation. Only one cue/target association was later reactivated and treated with behavioral interference. Our results showed, for the first time, that reactivation-coupled interference caused cue-independent memory impairment that generalized to other cues associated with the memory. Critically, such memory impairment appeared immediately after interference, before the reconsolidation process was completed, suggesting that common manipulations of reactivation-coupled interference procedures might disrupt other processes in addition to the reconsolidation process in human declarative memory. Copyright © 2016. Published by Elsevier B.V.

Retrieval from Episodic Memory: Neural Mechanisms of Interference Resolution

ERIC Educational Resources Information Center

Wimber, Maria; Rutschmann, Roland Marcus; Greenlee, Mark W.; Bauml, Karl-Heinz

2009-01-01

Selectively retrieving a target memory among related memories requires some degree of inhibitory control over interfering and competing memories, a process assumed to be supported by inhibitory mechanisms. Evidence from behavioral studies suggests that such inhibitory control can lead to subsequent forgetting of the interfering information, a…

Spatial Memory for Chinese and English.

ERIC Educational Resources Information Center

Tavassoli, Nader T.

2002-01-01

Investigated spatial memory for written words as a behavioral consequence of verbal processing differences. Across three experiments with Chinese and U.S. college students, spatial memory for real and nonsense words was greater for Chinese logographs than for alphabetic English words. This spatial memory advantage was absent for pictures and…

Can color changes alter the neural correlates of recognition memory? Manipulation of processing affects an electrophysiological indicator of conceptual implicit memory.

PubMed

Cui, Xiaoyu; Gao, Chuanji; Zhou, Jianshe; Guo, Chunyan

2016-09-28

It has been widely shown that recognition memory includes two distinct retrieval processes: familiarity and recollection. Many studies have shown that recognition memory can be facilitated when there is a perceptual match between the studied and the tested items. Most event-related potential studies have explored the perceptual match effect on familiarity on the basis of the hypothesis that the specific event-related potential component associated with familiarity is the FN400 (300-500 ms mid-frontal effect). However, it is currently unclear whether the FN400 indexes familiarity or conceptual implicit memory. In addition, on the basis of the findings of a previous study, the so-called perceptual manipulations in previous studies may also involve some conceptual alterations. Therefore, we sought to determine the influence of perceptual manipulation by color changes on recognition memory when the perceptual or the conceptual processes were emphasized. Specifically, different instructions (perceptually or conceptually oriented) were provided to the participants. The results showed that color changes may significantly affect overall recognition memory behaviorally and that congruent items were recognized with a higher accuracy rate than incongruent items in both tasks, but no corresponding neural changes were found. Despite the evident familiarity shown in the two tasks (the behavioral performance of recognition memory was much higher than at the chance level), the FN400 effect was found in conceptually oriented tasks, but not perceptually oriented tasks. It is thus highly interesting that the FN400 effect was not induced, although color manipulation of recognition memory was behaviorally shown, as seen in previous studies. Our findings of the FN400 effect for the conceptual but not perceptual condition support the explanation that the FN400 effect indexes conceptual implicit memory.

A light-stimulated synaptic transistor with synaptic plasticity and memory functions based on InGaZnO{sub x}–Al{sub 2}O{sub 3} thin film structure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, H. K.; Chen, T. P., E-mail: echentp@ntu.edu.sg; Liu, P.

In this work, a synaptic transistor based on the indium gallium zinc oxide (IGZO)–aluminum oxide (Al{sub 2}O{sub 3}) thin film structure, which uses ultraviolet (UV) light pulses as the pre-synaptic stimulus, has been demonstrated. The synaptic transistor exhibits the behavior of synaptic plasticity like the paired-pulse facilitation. In addition, it also shows the brain's memory behaviors including the transition from short-term memory to long-term memory and the Ebbinghaus forgetting curve. The synapse-like behavior and memory behaviors of the transistor are due to the trapping and detrapping processes of the holes, which are generated by the UV pulses, at the IGZO/Al{submore » 2}O{sub 3} interface and/or in the Al{sub 2}O{sub 3} layer.« less

Investigating Executive Working Memory and Phonological Short-Term Memory in Relation to Fluency and Self-Repair Behavior in L2 Speech.

PubMed

Georgiadou, Effrosyni; Roehr-Brackin, Karen

2017-08-01

This paper reports the findings of a study investigating the relationship of executive working memory (WM) and phonological short-term memory (PSTM) to fluency and self-repair behavior during an unrehearsed oral task performed by second language (L2) speakers of English at two levels of proficiency, elementary and lower intermediate. Correlational analyses revealed a negative relationship between executive WM and number of pauses in the lower intermediate L2 speakers. However, no reliable association was found in our sample between executive WM or PSTM and self-repair behavior in terms of either frequency or type of self-repair. Taken together, our findings suggest that while executive WM may enhance performance at the conceptualization and formulation stages of the speech production process, self-repair behavior in L2 speakers may depend on factors other than working memory.

Brain substrates of implicit and explicit memory: the importance of concurrently acquired neural signals of both memory types.

PubMed

Voss, Joel L; Paller, Ken A

2008-11-01

A comprehensive understanding of human memory requires cognitive and neural descriptions of memory processes along with a conception of how memory processing drives behavioral responses and subjective experiences. One serious challenge to this endeavor is that an individual memory process is typically operative within a mix of other contemporaneous memory processes. This challenge is particularly disquieting in the context of implicit memory, which, unlike explicit memory, transpires without the subject necessarily being aware of memory retrieval. Neural correlates of implicit memory and neural correlates of explicit memory are often investigated in different experiments using very different memory tests and procedures. This strategy poses difficulties for elucidating the interactions between the two types of memory process that may result in explicit remembering, and for determining the extent to which certain neural processing events uniquely contribute to only one type of memory. We review recent studies that have succeeded in separately assessing neural correlates of both implicit memory and explicit memory within the same paradigm using event-related brain potentials (ERPs) and functional magnetic resonance imaging (fMRI), with an emphasis on studies from our laboratory. The strategies we describe provide a methodological framework for achieving valid assessments of memory processing, and the findings support an emerging conceptualization of the distinct neurocognitive events responsible for implicit and explicit memory.

An Array Processing Theory of Memory, Thought, and Behavior Patterning: A Radically Reconstructive View.

ERIC Educational Resources Information Center

Allison, Dennis J.

A theory of memory is introduced, which seeks to respond to the shortcomings of existing theories based on metaphors. Memory is presented as a mechanism, a comparison process in which information held in some form of immediate storage (whether based on perception or previous cognition or both) is compared to previously stored long-term storage.…

Reading disabilities in children: A selective meta-analysis of the cognitive literature.

PubMed

Kudo, Milagros F; Lussier, Cathy M; Swanson, H Lee

2015-05-01

This article synthesizes literature that compares the academic, cognitive, and behavioral performance of children with and without reading disabilities (RD). Forty-eight studies met the criteria for the meta-analysis, yielding 735 effect sizes (ESs) with an overall weighted ES of 0.98. Small to high ESs in favor of children without RD emerged on measures of cognition (rapid naming [ES = 0.89], phonological awareness [ES = 1.00], verbal working memory [ES = 0.79], short-term memory [ES = 0.56], visual-spatial memory [ES = 0.48], and executive processing [ES = 0.67]), academic achievement (pseudoword reading [ES = 1.85], math [ES = 1.20], vocabulary [ES = 0.83], spelling [ES = 1.25], and writing [ES = 1.20]), and behavior skills (ES = 0.80). Hierarchical linear modeling indicated that specific cognitive process measures (verbal working memory, visual-spatial memory, executive processing, and short-term memory) and intelligence measures (general and verbal intelligence) significantly moderated overall group effect size differences. Overall, the results supported the assumption that cognitive deficits in children with RD are persistent. Copyright © 2015. Published by Elsevier Ltd.

Aging affects the interaction between attentional control and source memory: an fMRI study.

PubMed

Dulas, Michael R; Duarte, Audrey

2014-12-01

Age-related source memory impairments may be due, at least in part, to deficits in executive processes mediated by the PFC at both study and test. Behavioral work suggests that providing environmental support at encoding, such as directing attention toward item-source associations, may improve source memory and reduce age-related deficits in the recruitment of these executive processes. The present fMRI study investigated the effects of directed attention and aging on source memory encoding and retrieval. At study, participants were shown pictures of objects. They were either asked to attend to the objects and their color (source) or to their size. At test, participants determined if objects were seen before, and if so, whether they were the same color as previously. Behavioral results showed that direction of attention improved source memory for both groups; however, age-related deficits persisted. fMRI results revealed that, across groups, direction of attention facilitated medial temporal lobe-mediated contextual binding processes during study and attenuated right PFC postretrieval monitoring effects at test. However, persistent age-related source memory deficits may be related to increased recruitment of medial anterior PFC during encoding, indicative of self-referential processing, as well as underrecruitment of lateral anterior PFC-mediated relational processes. Taken together, this study suggests that, even when supported, older adults may fail to selectively encode goal-relevant contextual details supporting source memory performance.

Linalool Ameliorates Memory Loss and Behavioral Impairment Induced by REM-Sleep Deprivation through the Serotonergic Pathway.

PubMed

Lee, Bo Kyung; Jung, An Na; Jung, Yi-Sook

2018-07-01

Rapid eye movement (REM) sleep has an essential role in the process of learning and memory in the hippocampus. It has been reported that linalool, a major component of Lavandula angustifolia , has antioxidant, anti-inflammatory, and neuroprotective effects, along with other effects. However, the effect of linalool on the cognitive impairment and behavioral alterations that are induced by REM-sleep deprivation has not yet been elucidated. Several studies have reported that REM-sleep deprivation-induced memory deficits provide a well-known model of behavioral alterations. In the present study, we examined whether linalool elicited an anti-stress effect, reversing the behavioral alterations observed following REM-sleep deprivation in mice. Furthermore, we investigated the underlying mechanism of the effect of linalool. Spatial memory and learning memory were assessed through Y maze and passive avoidance tests, respectively, and the forced swimming test was used to evaluate anti-stress activity. The mechanisms through which linalool improves memory loss and behavioral alterations in sleep-deprived mice appeared to be through an increase in the serotonin levels. Linalool significantly ameliorated the spatial and learning memory deficits, and stress activity observed in sleep-deprived animals. Moreover, linalool led to serotonin release, and cortisol level reduction. Our findings suggest that linalool has beneficial effects on the memory loss and behavioral alterations induced by REM-sleep deprivation through the regulation of serotonin levels.

Criteria for identifying the molecular basis of the engram (CaMKII, PKMzeta).

PubMed

Lisman, John

2017-11-29

The engram refers to the molecular changes by which a memory is stored in the brain. Substantial evidence suggests that memory involves learning-dependent changes at synapses, a process termed long-term potentiation (LTP). Thus, understanding the storages process that underlies LTP may provide insight into how the engram is stored. LTP involves induction, maintenance (storage), and expression sub-processes; special tests are required to specifically reveal properties of the storage process. The strongest of these is the Erasure test in which a transiently applied agent that attacks a putative storage molecule may lead to persistent erasure of previously induced LTP/memory. Two major hypotheses have been proposed for LTP/memory storage: the CaMKII and PKM-zeta hypotheses. After discussing the tests that can be used to identify the engram (Necessity test, Saturation/Occlusion test, Erasure test), the status of these hypotheses is evaluated, based on the literature on LTP and memory-guided behavior. Review of the literature indicates that all three tests noted above support the CaMKII hypothesis when done at both the LTP level and at the behavioral level. Taken together, the results strongly suggest that the engram is stored by an LTP process in which CaMKII is a critical memory storage molecule.

Addiction memory as a specific, individually learned memory imprint.

PubMed

Böning, J

2009-05-01

The construct of "addiction memory" (AM) and its importance for relapse occurrence has been the subject of discussion for the past 30 years. Neurobiological findings from "social neuroscience" and biopsychological learning theory, in conjunction with construct-valid behavioral pharmacological animal models, can now also provide general confirmation of addiction memory as a pathomorphological correlate of addiction disorders. Under multifactorial influences, experience-driven neuronal learning and memory processes of emotional and cognitive processing patterns in the specific individual "set" and "setting" play an especially pivotal role in this connection. From a neuropsychological perspective, the episodic (biographical) memory, located at the highest hierarchical level, is of central importance for the formation of the AM in certain structural and functional areas of the brain and neuronal networks. Within this context, neuronal learning and conditioning processes take place more or less unconsciously and automatically in the preceding long-term-memory systems (in particular priming and perceptual memory). They then regulate the individually programmed addiction behavior implicitly and thus subsequently stand for facilitated recollection of corresponding, previously stored cues or context situations. This explains why it is so difficult to treat an addiction memory, which is embedded above all in the episodic memory, from the molecular carrier level via the neuronal pattern level through to the psychological meaning level, and has thus meanwhile become a component of personality.

Ghrelin: A link between memory and ingestive behavior

PubMed Central

Hsu, Ted M.; Suarez, Andrea N.; Kanoski, Scott E.

2016-01-01

Feeding is a highly complex behavior that is influenced by learned associations between external and internal cues. The type of excessive feeding behavior contributing to obesity onset and metabolic deficit may be based, in part, on conditioned appetitive and ingestive behaviors that occur in response to environmental and/or interoceptive cues associated with palatable food. Therefore, there is a critical need to understand the neurobiology underlying learned aspects of feeding behavior. The stomach-derived “hunger” hormone, ghrelin, stimulates appetite and food intake and may function as an important biological substrate linking mnemonic processes with feeding control. The current review highlights data supporting a role for ghrelin in mediating the cognitive and neurobiological mechanisms that underlie conditioned feeding behavior. We discuss the role of learning and memory on food intake control (with a particular focus on hippocampal-dependent memory processes) and provide an overview of conditioned cephalic endocrine responses. A neurobiological framework is provided through which conditioned cephalic ghrelin secretion signals in neurons in the hippocampus, which then engage orexigenic neural circuitry in the lateral hypothalamus to express learned feeding behavior. PMID:27072509

Neurocognitive architecture of working memory

PubMed Central

Eriksson, Johan; Vogel, Edward K.; Lansner, Anders; Bergström, Fredrik; Nyberg, Lars

2015-01-01

The crucial role of working memory for temporary information processing and guidance of complex behavior has been recognized for many decades. There is emerging consensus that working memory maintenance results from the interactions among long-term memory representations and basic processes, including attention, that are instantiated as reentrant loops between frontal and posterior cortical areas, as well as subcortical structures. The nature of such interactions can account for capacity limitations, lifespan changes, and restricted transfer after working-memory training. Recent data and models indicate that working memory may also be based on synaptic plasticity, and that working memory can operate on non-consciously perceived information. PMID:26447571

Cognitive Rehabilitation of Episodic Memory Disorders: From Theory to Practice

PubMed Central

Ptak, Radek; der Linden, Martial Van; Schnider, Armin

2010-01-01

Memory disorders are among the most frequent and most debilitating cognitive impairments following acquired brain damage. Cognitive remediation strategies attempt to restore lost memory capacity, provide compensatory techniques or teach the use of external memory aids. Memory rehabilitation has strongly been influenced by memory theory, and the interaction between both has stimulated the development of techniques such as spaced retrieval, vanishing cues or errorless learning. These techniques partly rely on implicit memory and therefore enable even patients with dense amnesia to acquire new information. However, knowledge acquired in this way is often strongly domain-specific and inflexible. In addition, individual patients with amnesia respond differently to distinct interventions. The factors underlying these differences have not yet been identified. Behavioral management of memory failures therefore often relies on a careful description of environmental factors and measurement of associated behavioral disorders such as unawareness of memory failures. The current evidence suggests that patients with less severe disorders benefit from self-management techniques and mnemonics whereas rehabilitation of severely amnesic patients should focus on behavior management, the transmission of domain-specific knowledge through implicit memory processes and the compensation for memory deficits with memory aids. PMID:20700383

Dynamic Hippocampal and Prefrontal Contributions to Memory Processes and Representations Blur the Boundaries of Traditional Cognitive Domains

PubMed Central

Schwarb, Hillary; Lucas, Heather D.; Dulas, Michael R.; Cohen, Neal J.

2017-01-01

The hippocampus has long been known to be a critical component of the memory system involved in the formation and use of long-term declarative memory. However, recent findings have revealed that the reach of hippocampal contributions extends to a variety of domains and tasks that require the flexible use of cognitive and social behavior, including domains traditionally linked to prefrontal cortex (PFC), such as decision-making. In addition, the prefrontal cortex (PFC) has gained traction as a necessary part of the memory system. These findings challenge the conventional characterizations of hippocampus and PFC as being circumscribed to traditional cognitive domains. Here, we emphasize that the ability to parsimoniously account for the breadth of hippocampal and PFC contributions to behavior, in terms of memory function and beyond, requires theoretical advances in our understanding of their characteristic processing features and mental representations. Notably, several literatures exist that touch upon this issue, but have remained disjointed because of methodological differences that necessarily limit the scope of inquiry, as well as the somewhat artificial boundaries that have been historically imposed between domains of cognition. In particular, this article focuses on the contribution of relational memory theory as an example of a framework that describes both the representations and processes supported by the hippocampus, and further elucidates the role of the hippocampal–PFC network to a variety of behaviors. PMID:28704928

Altered Intrinsic Hippocmapus Declarative Memory Network and Its Association with Impulsivity in Abstinent Heroin Dependent Subjects

PubMed Central

Zhai, Tian-Ye; Shao, Yong-Cong; Xie, Chun-Ming; Ye, En-Mao; Zou, Feng; Fu, Li-Ping; Li, Wen-Jun; Chen, Gang; Chen, Guang-Yu; Zhang, Zheng-Guo; Li, Shi-Jiang; Yang, Zheng

2014-01-01

Converging evidence suggests that addiction can be considered a disease of aberrant learning and memory with impulsive decision-making. In the past decades, numerous studies have demonstrated that drug addiction is involved in multiple memory systems such as classical conditioned drug memory, instrumental learning memory and the habitual learning memory. However, most of these studies have focused on the contributions of non-declarative memory, and declarative memory has largely been neglected in the research of addiction. Based on a recent finding that hippocampus, as a core functioning region of declarative memory, was proved biased the decision-making process based on past experiences by spreading associated reward values throughout memory. Our present study focused on the hippocampus. By utilizing seed-based network analysis on the resting-state functional MRI datasets with the seed hippocampus we tested how the intrinsic hippocampal memory network altered towards drug addiction, and examined how the functional connectivity strength within the altered hippocampal network correlated with behavioral index ‘impulsivity’. Our results demonstrated that HD group showed enhanced coherence between hippocampus which represents declarative memory system and non-declarative rewardguided learning memory system, and also showed attenuated intrinsic functional link between hippocampus and top-down control system, compared to the CN group. This alteration was furthered found to have behavioral significance over the behavioral index ‘impulsivity’ measured with Barratt Impulsiveness Scale (BIS). These results provide insights into the mechanism of declarative memory underlying the impulsive behavior in drug addiction. PMID:25008351

Updating appetitive memory during reconsolidation window: critical role of cue-directed behavior and amygdala central nucleus.

PubMed

Olshavsky, Megan E; Song, Bryan J; Powell, Daniel J; Jones, Carolyn E; Monfils, Marie-H; Lee, Hongjoo J

2013-01-01

When presented with a light cue followed by food, some rats simply approach the foodcup (Nonorienters), while others first orient to the light in addition to displaying the food-cup approach behavior (Orienters). Cue-directed orienting may reflect enhanced attentional and/or emotional processing of the cue, suggesting divergent natures of cue-information processing in Orienters and Nonorienters. The current studies investigate how differences in cue processing might manifest in appetitive memory retrieval and updating using a paradigm developed to persistently attenuate fear responses (Retrieval-extinction paradigm; Monfils et al., 2009). First, we examined whether the retrieval-extinction paradigm could attenuate appetitive responses in Orienters and Nonorienters. Next, we investigated if the appetitive memory could be updated using reversal learning (fear conditioning) during the reconsolidation window (as opposed to repeated unreinforced trials, i.e., extinction). Both extinction and new fear learning given within the reconsolidation window were effective at persistently updating the initial appetitive memory in the Orienters, but not the Nonorienters. Since conditioned orienting is mediated by the amygdala central nucleus (CeA), our final experiment examined the CeA's role in the retrieval-extinction process. Bilateral CeA lesions interfered with the retrieval-extinction paradigm-did not prevent spontaneous recovery of food-cup approach. Together, our studies demonstrate the critical role of conditioned orienting behavior and the CeA in updating appetitive memory during the reconsolidation window.

Deliberative and spontaneous cognitive processes associated with HIV risk behavior

PubMed Central

Ames, Susan L.; Stacy, Alan W.

2012-01-01

Dual process models of decision-making suggest that behavior is mediated by a spontaneous behavior selection process or by a more deliberative evaluation of behavioral options. We examined whether the deliberative system moderates the influence of spontaneous cognition on HIV-risk behaviors. A measure of spontaneous sex-related associations (word association), a measure of deliberative working memory capacity (operation span), and two measures of sexual behavior (condom use and multiple partners) were assessed in a cross-sectional study among 490 adult drug offenders. Significant effects were observed among men but not among women in two latent interaction models. In a novel finding, the accessibility of spontaneous safe sex-related associations was significantly more predictive of condom use among men with higher working memory capacity than among men with lower capacity. These results have implications for the design of interventions to promote safe sex practices. PMID:22331437

Consolidation power of extrinsic rewards: reward cues enhance long-term memory for irrelevant past events.

PubMed

Murayama, Kou; Kitagami, Shinji

2014-02-01

Recent research suggests that extrinsic rewards promote memory consolidation through dopaminergic modulation processes. However, no conclusive behavioral evidence exists given that the influence of extrinsic reward on attention and motivation during encoding and consolidation processes are inherently confounded. The present study provides behavioral evidence that extrinsic rewards (i.e., monetary incentives) enhance human memory consolidation independently of attention and motivation. Participants saw neutral pictures, followed by a reward or control cue in an unrelated context. Our results (and a direct replication study) demonstrated that the reward cue predicted a retrograde enhancement of memory for the preceding neutral pictures. This retrograde effect was observed only after a delay, not immediately upon testing. An additional experiment showed that emotional arousal or unconscious resource mobilization cannot explain the retrograde enhancement effect. These results provide support for the notion that the dopaminergic memory consolidation effect can result from extrinsic reward.

Analysis of intelligent hinged shell structures: deployable deformation and shape memory effect

NASA Astrophysics Data System (ADS)

Shi, Guang-Hui; Yang, Qing-Sheng; He, X. Q.

2013-12-01

Shape memory polymers (SMPs) are a class of intelligent materials with the ability to recover their initial shape from a temporarily fixable state when subjected to external stimuli. In this work, the thermo-mechanical behavior of a deployable SMP-based hinged structure is modeled by the finite element method using a 3D constitutive model with shape memory effect. The influences of hinge structure parameters on the nonlinear loading process are investigated. The total shape memory of the processes the hinged structure goes through, including loading at high temperature, decreasing temperature with load carrying, unloading at low temperature and recovering the initial shape with increasing temperature, are illustrated. Numerical results show that the present constitutive theory and the finite element method can effectively predict the complicated thermo-mechanical deformation behavior and shape memory effect of SMP-based hinged shell structures.

The Neural Representations Underlying Human Episodic Memory.

PubMed

Xue, Gui

2018-06-01

A fundamental question of human episodic memory concerns the cognitive and neural representations and processes that give rise to the neural signals of memory. By integrating behavioral tests, formal computational models, and neural measures of brain activity patterns, recent studies suggest that memory signals not only depend on the neural processes and representations during encoding and retrieval, but also on the interaction between encoding and retrieval (e.g., transfer-appropriate processing), as well as on the interaction between the tested events and all other events in the episodic memory space (e.g., global matching). In addition, memory signals are also influenced by the compatibility of the event with the existing long-term knowledge (e.g., schema matching). These studies highlight the interactive nature of human episodic memory. Copyright © 2018 Elsevier Ltd. All rights reserved.

Targeting extinction and reconsolidation mechanisms to combat the impact of drug cues on addiction.

PubMed

Taylor, Jane R; Olausson, Peter; Quinn, Jennifer J; Torregrossa, Mary M

2009-01-01

Drug addiction is a progressive and compulsive disorder, where recurrent craving and relapse to drug-seeking occur even after long periods of abstinence. A major contributing factor to relapse is drug-associated cues. Here we review behavioral and pharmacological studies outlining novel methods of effective and persistent reductions in cue-induced relapse behavior in animal models. We focus on extinction and reconsolidation of cue-drug associations as the memory processes that are the most likely targets for interventions. Extinction involves the formation of new inhibitory memories rather than memory erasure; thus, it should be possible to facilitate the extinction of cue-drug memories to reduce relapse. We propose that context-dependency of extinction might be altered by mnemonic agents, thereby enhancing the efficacy of cue-exposure therapy as treatment strategy. In contrast, interfering with memory reconsolidation processes can disrupt the integrity or strength of specific cue-drug memories. Reconsolidation is argued to be a distinct process that occurs over a brief time period after memory is reactivated/retrieved - when the memory becomes labile and vulnerable to disruption. Reconsolidation is thought to be an independent, perhaps opposing, process to extinction and disruption of reconsolidation has recently been shown to directly affect subsequent cue-drug memory retrieval in an animal model of relapse. We hypothesize that a combined approach aimed at both enhancing the consolidation of cue-drug extinction and interfering with the reconsolidation of cue-drug memories will have a greater potential for persistently inhibiting cue-induced relapse than either treatment alone.

Solution-processed flexible NiO resistive random access memory device

NASA Astrophysics Data System (ADS)

Kim, Soo-Jung; Lee, Heon; Hong, Sung-Hoon

2018-04-01

Non-volatile memories (NVMs) using nanocrystals (NCs) as active materials can be applied to soft electronic devices requiring a low-temperature process because NCs do not require a heat treatment process for crystallization. In addition, memory devices can be implemented simply by using a patterning technique using a solution process. In this study, a flexible NiO ReRAM device was fabricated using a simple NC patterning method that controls the capillary force and dewetting of a NiO NC solution at low temperature. The switching behavior of a NiO NC based memory was clearly observed by conductive atomic force microscopy (c-AFM).

Memory reconsolidation, emotional arousal, and the process of change in psychotherapy: New insights from brain science.

PubMed

Lane, Richard D; Ryan, Lee; Nadel, Lynn; Greenberg, Leslie

2015-01-01

Since Freud, clinicians have understood that disturbing memories contribute to psychopathology and that new emotional experiences contribute to therapeutic change. Yet, controversy remains about what is truly essential to bring about psychotherapeutic change. Mounting evidence from empirical studies suggests that emotional arousal is a key ingredient in therapeutic change in many modalities. In addition, memory seems to play an important role but there is a lack of consensus on the role of understanding what happened in the past in bringing about therapeutic change. The core idea of this paper is that therapeutic change in a variety of modalities, including behavioral therapy, cognitive-behavioral therapy, emotion-focused therapy, and psychodynamic psychotherapy, results from the updating of prior emotional memories through a process of reconsolidation that incorporates new emotional experiences. We present an integrated memory model with three interactive components - autobiographical (event) memories, semantic structures, and emotional responses - supported by emerging evidence from cognitive neuroscience on implicit and explicit emotion, implicit and explicit memory, emotion-memory interactions, memory reconsolidation, and the relationship between autobiographical and semantic memory. We propose that the essential ingredients of therapeutic change include: (1) reactivating old memories; (2) engaging in new emotional experiences that are incorporated into these reactivated memories via the process of reconsolidation; and (3) reinforcing the integrated memory structure by practicing a new way of behaving and experiencing the world in a variety of contexts. The implications of this new, neurobiologically grounded synthesis for research, clinical practice, and teaching are discussed.

Reward Retroactively Enhances Memory Consolidation for Related Items

ERIC Educational Resources Information Center

Patil, Anuya; Murty, Vishnu P.; Dunsmoor, Joseph E.; Phelps, Elizabeth A.; Davachi, Lila

2017-01-01

Reward motivation has been shown to modulate episodic memory processes in order to support future adaptive behavior. However, for a memory system to be truly adaptive, it should enhance memory for rewarded events as well as for neutral events that may seem inconsequential at the time of encoding but can gain importance later. Here, we investigated…

Dreaming and offline memory processing.

PubMed

Wamsley, Erin J; Stickgold, Robert

2010-12-07

The activities of the mind and brain never cease. Although many of our waking hours are spent processing sensory input and executing behavioral responses, moments of unoccupied rest free us to wander through thoughts of the past and future, create daydreams, and imagine fictitious scenarios. During sleep, when attention to sensory input is at a minimum, the mind continues to process information, using memory fragments to create the images, thoughts, and narratives that we commonly call 'dreaming'. Far from being a random or meaningless distraction, spontaneous cognition during states of sleep and resting wakefulness appears to serve important functions related to processing past memories and planning for the future. From single-cell recordings in rodents to behavioral studies in humans, recent studies in the neurosciences suggest a new conception of dreaming as part of a continuum of adaptive cognitive processing occurring across the full range of mind/brain states. Copyright © 2010 Elsevier Ltd. All rights reserved.

Categorizing Others and the Self: How Social Memory Structures Guide Social Perception and Behavior

ERIC Educational Resources Information Center

Quinn, Kimberly A.; Rosenthal, Harriet E. S.

2012-01-01

In keeping with the special issue theme of "Remembering the Future," this article provides a selective review of research on how memory for social information (i.e., social category representation) influences future processing and behavior. Specifically, the authors focus on how categorization and stereotyping affect how we perceive others and…

Reconsolidation of a Well-Learned Instrumental Memory

ERIC Educational Resources Information Center

Exton-McGuinness, Marc T. J.; Patton, Rosemary C.; Sacco, Lawrence B.; Lee, Jonathan L. C.

2014-01-01

Once consolidated, memories are dynamic entities that go through phases of instability in order to be updated with new information, via a process of reconsolidation. The phenomenon of reconsolidation has been demonstrated in a wide variety of experimental paradigms. However, the memories underpinning instrumental behaviors are currently not…

The Influence of Learning Strategies in the Acquisition, Retention, and Transfer of a Procedural Task.

DTIC Science & Technology

1979-08-01

Lockhart , R. S. Levels of processing : A framework for memory research. Journal of Verbal Learning and Verbal Behavior, 1972, 11, 671-684. Craik , F. I. M...learning and memory research. In F. I. f. Craik & L. S. Cermak (Eds.), Levels of processing and theories of memory. Hillsdale, N. J.: Erlbaum, 1978...R. N., Gerson, R. F., & Kim, K. Information processing capabilities in performers differing in levels of motor skill. (Tech. Rep. TR-79-A4). a

Toward a better understanding on the role of prediction error on memory processes: From bench to clinic.

PubMed

Krawczyk, María C; Fernández, Rodrigo S; Pedreira, María E; Boccia, Mariano M

2017-07-01

Experimental psychology defines Prediction Error (PE) as a mismatch between expected and current events. It represents a unifier concept within the memory field, as it is the driving force of memory acquisition and updating. Prediction error induces updating of consolidated memories in strength or content by memory reconsolidation. This process has two different neurobiological phases, which involves the destabilization (labilization) of a consolidated memory followed by its restabilization. The aim of this work is to emphasize the functional role of PE on the neurobiology of learning and memory, integrating and discussing different research areas: behavioral, neurobiological, computational and clinical psychiatry. Copyright © 2016 Elsevier Inc. All rights reserved.

Age-related changes in overcoming proactive interference in associative memory: The role of PFC-mediated executive control processes at retrieval.

PubMed

Dulas, Michael R; Duarte, Audrey

2016-05-15

Behavioral evidence has shown age-related impairments in overcoming proactive interference in memory, but it is unclear what underlies this deficit. Imaging studies in the young suggest overcoming interference may require several executive control processes supported by the ventrolateral prefrontal cortex (VLPFC) and dorsolateral PFC (DLPFC). The present functional magnetic resonance imaging (fMRI) study investigated whether age-related changes in dissociable executive control processes underlie deficits in overcoming proactive interference in associative memory during retrieval. Participants were tasked with remembering which associate (face or scene) objects were paired with most recently during study, under conditions of high or low proactive interference. Behavioral results demonstrated that, as interference increased, memory performance decreased similarly across groups, with slight associative memory deficits in older adults. Imaging results demonstrated that, across groups, left mid-VLPFC showed increasing activity with increasing interference, though activity did not distinguish correct from incorrect associative memory responses, suggesting this region may not directly serve in successful resolution of proactive interference, per se. Under conditions of high interference, older adults showed reduced associative memory accuracy effects in the DLPFC and anterior PFC. These results suggest that age-related PFC dysfunction may not be ubiquitous. Executive processes supported by ventral regions that detect mnemonic interference may be less affected than processes supported by dorsal and anterior regions that directly resolve interference. Copyright © 2016 Elsevier Inc. All rights reserved.

Effects of the swimming exercise on the consolidation and persistence of auditory and contextual fear memory.

PubMed

Faria, Rodolfo Souza; Gutierres, Luís Felipe Soares; Sobrinho, Fernando César Faria; Miranda, Iris do Vale; Reis, Júlia Dos; Dias, Elayne Vieira; Sartori, Cesar Renato; Moreira, Dalmo Antonio Ribeiro

2016-08-15

Exposure to negative environmental events triggers defensive behavior and leads to the formation of aversive associative memory. Cellular and molecular changes in the central nervous system underlie this memory formation, as well as the associated behavioral changes. In general, memory process is established in distinct phases such as acquisition, consolidation, evocation, persistence, and extinction of the acquired information. After exposure to a particular event, early changes in involved neural circuits support the memory consolidation, which corresponds to the short-term memory. Re-exposure to previously memorized events evokes the original memory, a process that is considered essential for the reactivation and consequent persistence of memory, ensuring that long-term memory is established. Different environmental stimuli may modulate the memory formation process, as well as their distinct phases. Among the different environmental stimuli able of modulating memory formation is the physical exercise which is a potent modulator of neuronal activity. There are many studies showing that physical exercise modulates learning and memory processes, mainly in the consolidation phase of the explicit memory. However, there are few reports in the literature regarding the role of physical exercise in implicit aversive associative memory, especially at the persistence phase. Thus, the present study aimed to investigate the relationship between swimming exercise and the consolidation and persistence of contextual and auditory-cued fear memory. Male Wistar rats were submitted to sessions of swimming exercise five times a week, over six weeks. After that, the rats were submitted to classical aversive conditioning training by a pairing tone/foot shock paradigm. Finally, rats were evaluated for consolidation and persistence of fear memory to both auditory and contextual cues. Our results demonstrate that classical aversive conditioning with tone/foot shock pairing induced consolidation as well as persistence of conditioned fear memory. In addition, rats submitted to swimming exercise over six weeks showed an improved performance in the test of auditory-cued fear memory persistence, but not in the test of contextual fear memory persistence. Moreover, no significant effect from swimming exercise was observed on consolidation of both contextual and auditory fear memory. So, our study, revealing the effect of the swimming exercise on different stages of implicit memory of tone/foot shock conditioning, contributes to and complements the current knowledge about the environmental modulation of memory process. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Intelligence as it relates to conscious and unconscious memory influences.

PubMed

Joordens, Steve; Walsh, Darlene; Mantonakis, Antonia

2013-09-01

We examine the relationship between a measure of intelligence and estimates of conscious and unconscious memory influences derived using Jacoby's (Jacoby, L. L. [1991]. A process dissociation framework: Separating automatic from intentional uses of memory. Journal of Memory and Language, 30, 513-541.) process-dissociation procedure. We find a positive relationship between intelligence and conscious memory, and no relationship between intelligence and unconscious influences once the impact of conscious influences are removed (Experiment 1). We also find that when participants cannot engage in conscious strategies, such as when there is insufficient time for learning, the relationships observed in Experiment 1 are eliminated (Experiments 2A and 2B). Our results support the notion that individual differences in intelligence reflect differences in conscious strategic processes (Karis, D., Fabiani, M., & Donchin, E. [1984]. "P300" and memory: Individual differences in the von Restorff effect. Cognitive Psychology, 16, 177-216.) and not differences in mental speed (Eysenck, H. J. (1984). Intelligence versus behavior. The Behavioral and Brain Sciences, 7, 290-291; Jensen, A. R. [1982]. Bias in mental testing. New York, NY: Free Press). PsycINFO Database Record (c) 2013 APA, all rights reserved

Heterozygous Che-1 KO mice show deficiencies in object recognition memory persistence.

PubMed

Zalcman, Gisela; Corbi, Nicoletta; Di Certo, Maria Grazia; Mattei, Elisabetta; Federman, Noel; Romano, Arturo

2016-10-06

Transcriptional regulation is a key process in the formation of long-term memories. Che-1 is a protein involved in the regulation of gene transcription that has recently been proved to bind the transcription factor NF-κB, which is known to be involved in many memory-related molecular events. This evidence prompted us to investigate the putative role of Che-1 in memory processes. For this study we newly generated a line of Che-1(+/-) heterozygous mice. Che-1 homozygous KO mouse is lethal during development, but Che-1(+/-) heterozygous mouse is normal in its general anatomical and physiological characteristics. We analyzed the behavioral characteristic and memory performance of Che-1(+/-) mice in two NF-κB dependent types of memory. We found that Che-1(+/-) mice show similar locomotor activity and thigmotactic behavior than wild type (WT) mice in an open field. In a similar way, no differences were found in anxiety-like behavior between Che-1(+/-) and WT mice in an elevated plus maze as well as in fear response in a contextual fear conditioning (CFC) and object exploration in a novel object recognition (NOR) task. No differences were found between WT and Che-1(+/-) mice performance in CFC training and when tested at 24h or 7days after training. Similar performance was found between groups in NOR task, both in training and 24h testing performance. However, we found that object recognition memory persistence at 7days was impaired in Che-1(+/-) heterozygous mice. This is the first evidence showing that Che-1 is involved in memory processes. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Medial prefrontal cortex supports source memory for self-referenced materials in young and older adults

PubMed Central

Leshikar, Eric D.; Duarte, Audrey

2013-01-01

Behavioral evidence suggests that young and older adults show a benefit in source memory accuracy when processing materials in reference to the self. In the young, activity within the medial prefrontal cortex supports this source memory benefit at study. This investigation examined whether the same neural regions support this memory benefit in both age groups. Using fMRI, participants were scanned while studying and retrieving pictures of objects paired with one of three scenes (source) under self-reference and other-reference conditions. At the time of study, half of the items were presented once and half twice, allowing us to match behavioral performance between groups. Both groups showed equivalent source accuracy benefit for objects encoded self-referentially. Activity in the left dorsal medial prefrontal cortex supported subsequent source memory in both age groups for the self-referenced relative to the other-referenced items. At the time of test, source accuracy for both self- and other-referenced items was supported by a network of regions including the precuneus in both age groups. At both study and test, little in the way of age-differences emerged, suggesting that when matched on behavioral performance young and older adults engage similar regions in support of source memory when processing materials in reference to the self; however, when performance was not matched, age differences in functional recruitment were prevalent. These results suggest that by capitalizing on preserved processes (self-referential encoding), older adults can show improvement in memory for source details which typically are not well remembered relative to the young. PMID:23904335

Dual operation characteristics of resistance random access memory in indium-gallium-zinc-oxide thin film transistors

NASA Astrophysics Data System (ADS)

Yang, Jyun-Bao; Chang, Ting-Chang; Huang, Jheng-Jie; Chen, Yu-Chun; Chen, Yu-Ting; Tseng, Hsueh-Chih; Chu, Ann-Kuo; Sze, Simon M.

2014-04-01

In this study, indium-gallium-zinc-oxide thin film transistors can be operated either as transistors or resistance random access memory devices. Before the forming process, current-voltage curve transfer characteristics are observed, and resistance switching characteristics are measured after a forming process. These resistance switching characteristics exhibit two behaviors, and are dominated by different mechanisms. The mode 1 resistance switching behavior is due to oxygen vacancies, while mode 2 is dominated by the formation of an oxygen-rich layer. Furthermore, an easy approach is proposed to reduce power consumption when using these resistance random access memory devices with the amorphous indium-gallium-zinc-oxide thin film transistor.

Altered intrinsic hippocmapus declarative memory network and its association with impulsivity in abstinent heroin dependent subjects.

PubMed

Zhai, Tian-Ye; Shao, Yong-Cong; Xie, Chun-Ming; Ye, En-Mao; Zou, Feng; Fu, Li-Ping; Li, Wen-Jun; Chen, Gang; Chen, Guang-Yu; Zhang, Zheng-Guo; Li, Shi-Jiang; Yang, Zheng

2014-10-01

Converging evidence suggests that addiction can be considered a disease of aberrant learning and memory with impulsive decision-making. In the past decades, numerous studies have demonstrated that drug addiction is involved in multiple memory systems such as classical conditioned drug memory, instrumental learning memory and the habitual learning memory. However, most of these studies have focused on the contributions of non-declarative memory, and declarative memory has largely been neglected in the research of addiction. Based on a recent finding that hippocampus, as a core functioning region of declarative memory, was proved biased the decision-making process based on past experiences by spreading associated reward values throughout memory. Our present study focused on the hippocampus. By utilizing seed-based network analysis on the resting-state functional MRI datasets with the seed hippocampus we tested how the intrinsic hippocampal memory network altered toward drug addiction, and examined how the functional connectivity strength within the altered hippocampal network correlated with behavioral index 'impulsivity'. Our results demonstrated that HD group showed enhanced coherence between hippocampus which represents declarative memory system and non-declarative reward-guided learning memory system, and also showed attenuated intrinsic functional link between hippocampus and top-down control system, compared to the CN group. This alteration was furthered found to have behavioral significance over the behavioral index 'impulsivity' measured with Barratt Impulsiveness Scale (BIS). These results provide insights into the mechanism of declarative memory underlying the impulsive behavior in drug addiction. Copyright © 2014 Elsevier B.V. All rights reserved.

Selective transfer of visual working memory training on Chinese character learning.

PubMed

Opitz, Bertram; Schneiders, Julia A; Krick, Christoph M; Mecklinger, Axel

2014-01-01

Previous research has shown a systematic relationship between phonological working memory capacity and second language proficiency for alphabetic languages. However, little is known about the impact of working memory processes on second language learning in a non-alphabetic language such as Mandarin Chinese. Due to the greater complexity of the Chinese writing system we expect that visual working memory rather than phonological working memory exerts a unique influence on learning Chinese characters. This issue was explored in the present experiment by comparing visual working memory training with an active (auditory working memory training) control condition and a passive, no training control condition. Training induced modulations in language-related brain networks were additionally examined using functional magnetic resonance imaging in a pretest-training-posttest design. As revealed by pre- to posttest comparisons and analyses of individual differences in working memory training gains, visual working memory training led to positive transfer effects on visual Chinese vocabulary learning compared to both control conditions. In addition, we found sustained activation after visual working memory training in the (predominantly visual) left infero-temporal cortex that was associated with behavioral transfer. In the control conditions, activation either increased (active control condition) or decreased (passive control condition) without reliable behavioral transfer effects. This suggests that visual working memory training leads to more efficient processing and more refined responses in brain regions involved in visual processing. Furthermore, visual working memory training boosted additional activation in the precuneus, presumably reflecting mental image generation of the learned characters. We, therefore, suggest that the conjoint activity of the mid-fusiform gyrus and the precuneus after visual working memory training reflects an interaction of working memory and imagery processes with complex visual stimuli that fosters the coherent synthesis of a percept from a complex visual input in service of enhanced Chinese character learning. © 2013 Published by Elsevier Ltd.

Thermomechanical Modeling of Shape Memory Alloys and Applications

NASA Astrophysics Data System (ADS)

Lexcellent, C.; Leclercq, S.

The aim of the present paper is a general macroscopic description of the thermomechanical behavior of shape memory alloys (SMA). We use for framework the thermodynamics of irreversible processes. This model is efficient for describing the behavior of "smart" structures as a bronchial, a tentacle element and an prosthesis hybrid structure made of Ti Ni SMA wires embedded in a resin epoxy matrix.

Demonstration of an ebbinghaus illusion at a memory level: manipulation of the memory size and not the perceptual size.

PubMed

Rey, Amandine Eve; Riou, Benoit; Versace, Rémy

2014-01-01

Based on recent behavioral and neuroimaging data suggesting that memory and perception are partially based on the same sensorimotor system, the theoretical aim of the present study was to show that it is difficult to dissociate memory mechanisms from perceptual mechanisms other than on the basis of the presence (perceptual processing) or absence (memory processing) of the characteristics of the objects involved in the processing. In line with this assumption, two experiments using an adaptation of the Ebbinghaus illusion paradigm revealed similar effects irrespective of whether the size difference between the inner circles and the surrounding circles was manipulated perceptually (the size difference was perceptually present, Experiment 1) or merely reactivated in memory (the difference was perceptually absent, Experiment 2).

Old/New Effect of Digital Memory Retrieval in Chinese Dyscalculia.

PubMed

Wang, Enguo; Du, Chenguang; Ma, Yujun

This study reports the neurophysiological and behavioral correlates of digital memory retrieval features in Chinese individuals with and without dyscalculia. A total of 18 children with dyscalculia (ages 11.5-13.5) and 18 controls were tested, and their event-related potentials were digitally recorded simultaneously with behavior measurement. Behavioral data showed that the dyscalculia group had lower hit rates and higher false rates than the control group. The electroencephalography results showed that both groups had a significant old/new effect and that this effect was greater in the control group. In the 300 to 400 ms processing stages, both groups showed significant differences in digital memory retrieval in the frontal regions. In the 400 to 500 and 500 to 600 ms epochs, the old/new effect in the control group was significantly greater than it was in the dyscalculia group at the frontal, central, and parietal regions. In the 600 to 700 ms processing stages, both groups showed significant differences in digital memory retrieval in the frontal, central, parietal, and occipital regions. These results suggest that individuals with dyscalculia exhibit impaired digital memory retrieval. Extraction failure may be an important cause of calculation difficulties.

Episodic memory in former professional football players with a history of concussion: an event-related functional neuroimaging study.

PubMed

Ford, Jaclyn H; Giovanello, Kelly S; Guskiewicz, Kevin M

2013-10-15

Previous research has demonstrated that sport-related concussions can have short-term effects on cognitive processes, but the long-term consequences are less understood and warrant more research. This study was the first to use event-related functional magnetic resonance imaging (fMRI) to examine long-term differences in neural activity during memory tasks in former athletes who have sustained multiple sport-related concussions. In an event-related fMRI study, former football players reporting multiple sport-related concussions (i.e., three or more) were compared with players who reported fewer than three concussions during a memory paradigm examining item memory (i.e., memory for the particular elements of an event) and relational memory (i.e., memory for the relationships between elements). Behaviorally, we observed that concussion history did not significantly affect behavioral performance, because persons in the low and high concussion groups had equivalent performance on both memory tasks, and in addition, that concussion history was not associated with any behavioral memory measures. Despite demonstrating equivalent behavioral performance, the two groups of former players demonstrated different neural recruitment patterns during relational memory retrieval, suggesting that multiple concussions may be associated with functional inefficiencies in the relational memory network. In addition, the number of previous concussions significantly correlated with functional activity in a number of brain regions, including the medial temporal lobe and inferior parietal lobe. Our results provide important insights in understanding the long-term functional consequences of sustaining multiple sports-related concussions.

Control of working memory: effects of attention training on target recognition and distractor salience in an auditory selection task.

PubMed

Melara, Robert D; Tong, Yunxia; Rao, Aparna

2012-01-09

Behavioral and electrophysiological measures of target and distractor processing were examined in an auditory selective attention task before and after three weeks of distractor suppression training. Behaviorally, training improved target recognition and led to less conservative and more rapid responding. Training also effectively shortened the temporal distance between distractors and targets needed to achieve a fixed level of target sensitivity. The effects of training on event-related potentials were restricted to the distracting stimulus: earlier N1 latency, enhanced P2 amplitude, and weakened P3 amplitude. Nevertheless, as distractor P2 amplitude increased, so too did target P3 amplitude, connecting experience-dependent changes in distractor processing with greater distinctiveness of targets in working memory. We consider the effects of attention training on the processing priorities, representational noise, and inhibitory processes operating in working memory. Copyright © 2011 Elsevier B.V. All rights reserved.

Interference Conditions of the Reconsolidation Process in Humans: The Role of Valence and Different Memory Systems

PubMed Central

Fernández, Rodrigo S.; Bavassi, Luz; Kaczer, Laura; Forcato, Cecilia; Pedreira, María E.

2016-01-01

Following the presentation of a reminder, consolidated memories become reactivated followed by a process of re-stabilization, which is referred to as reconsolidation. The most common behavioral tool used to reveal this process is interference produced by new learning shortly after memory reactivation. Memory interference is defined as a decrease in memory retrieval, the effect is generated when new information impairs an acquired memory. In general, the target memory and the interference task used are the same. Here we investigated how different memory systems and/or their valence could produce memory reconsolidation interference. We showed that a reactivated neutral declarative memory could be interfered by new learning of a different neutral declarative memory. Then, we revealed that an aversive implicit memory could be interfered by the presentation of a reminder followed by a threatening social event. Finally, we showed that the reconsolidation of a neutral declarative memory is unaffected by the acquisition of an aversive implicit memory and conversely, this memory remains intact when the neutral declarative memory is used as interference. These results suggest that the interference of memory reconsolidation is effective when two task rely on the same memory system or both evoke negative valence. PMID:28066212

Interference Conditions of the Reconsolidation Process in Humans: The Role of Valence and Different Memory Systems.

PubMed

Fernández, Rodrigo S; Bavassi, Luz; Kaczer, Laura; Forcato, Cecilia; Pedreira, María E

2016-01-01

Following the presentation of a reminder, consolidated memories become reactivated followed by a process of re-stabilization, which is referred to as reconsolidation. The most common behavioral tool used to reveal this process is interference produced by new learning shortly after memory reactivation. Memory interference is defined as a decrease in memory retrieval, the effect is generated when new information impairs an acquired memory. In general, the target memory and the interference task used are the same. Here we investigated how different memory systems and/or their valence could produce memory reconsolidation interference. We showed that a reactivated neutral declarative memory could be interfered by new learning of a different neutral declarative memory. Then, we revealed that an aversive implicit memory could be interfered by the presentation of a reminder followed by a threatening social event. Finally, we showed that the reconsolidation of a neutral declarative memory is unaffected by the acquisition of an aversive implicit memory and conversely, this memory remains intact when the neutral declarative memory is used as interference. These results suggest that the interference of memory reconsolidation is effective when two task rely on the same memory system or both evoke negative valence.

Double dynamic scaling in human communication dynamics

NASA Astrophysics Data System (ADS)

Wang, Shengfeng; Feng, Xin; Wu, Ye; Xiao, Jinhua

2017-05-01

In the last decades, human behavior has been deeply understanding owing to the huge quantities data of human behavior available for study. The main finding in human dynamics shows that temporal processes consist of high-activity bursty intervals alternating with long low-activity periods. A model, assuming the initiator of bursty follow a Poisson process, is widely used in the modeling of human behavior. Here, we provide further evidence for the hypothesis that different bursty intervals are independent. Furthermore, we introduce a special threshold to quantitatively distinguish the time scales of complex dynamics based on the hypothesis. Our results suggest that human communication behavior is a composite process of double dynamics with midrange memory length. The method for calculating memory length would enhance the performance of many sequence-dependent systems, such as server operation and topic identification.

Reducing Misanthropic Memory Through Self-Awareness: Reducing Bias.

PubMed

Davis, Mark D

2015-01-01

Two experiments investigated the influence of self-awareness on misanthropic recall. Misanthropic recall is the tendency to recall more negative behaviors dispositionally attributed and positive behaviors situationally attributed than negative behaviors situationally attributed and positive behaviors dispositionally attributed. It was hypothesized that when one is self-aware, more systematic information processing would occur, thereby reducing misanthropic memory and influencing attitudinal judgments. The first experiment used a mirror and the second experiment used a live video to induce self-awareness. Participants were asked to form an impression of a group. The results of both experiments replicated the previously found pattern of misanthropic memory for non-self-aware participants (Ybarra & Stephan, 1996), and revealed less misanthropic recall bias in self-aware participants.

ERP correlates of object recognition memory in Down syndrome: Do active and passive tasks measure the same thing?

PubMed

Van Hoogmoed, A H; Nadel, L; Spanò, G; Edgin, J O

2016-02-01

Event related potentials (ERPs) can help to determine the cognitive and neural processes underlying memory functions and are often used to study populations with severe memory impairment. In healthy adults, memory is typically assessed with active tasks, while in patient studies passive memory paradigms are generally used. In this study we examined whether active and passive continuous object recognition tasks measure the same underlying memory process in typically developing (TD) adults and in individuals with Down syndrome (DS), a population with known hippocampal impairment. We further explored how ERPs in these tasks relate to behavioral measures of memory. Data-driven analysis techniques revealed large differences in old-new effects in the active versus passive task in TD adults, but no difference between these tasks in DS. The group with DS required additional processing in the active task in comparison to the TD group in two ways. First, the old-new effect started 150 ms later. Second, more repetitions were required to show the old-new effect. In the group with DS, performance on a behavioral measure of object-location memory was related to ERP measures across both tasks. In total, our results suggest that active and passive ERP memory measures do not differ in DS and likely reflect the use of implicit memory, but not explicit processing, on both tasks. Our findings highlight the need for a greater understanding of the comparison between active and passive ERP paradigms before they are inferred to measure similar functions across populations (e.g., infants or intellectual disability). Copyright © 2016 Elsevier Ltd. All rights reserved.

An Evaluation of Recollection and Familiarity in Alzheimer's Disease and Mild Cognitive Impairment Using Receiver Operating Characteristics

ERIC Educational Resources Information Center

Ally, Brandon A.; Gold, Carl A.; Budson, Andrew E.

2009-01-01

There is a need to investigate exactly how memory breaks down in the course of Alzheimer's disease (AD). Examining what aspects of memorial processing remain relatively intact early in the disease process will allow us to develop behavioral interventions and possible drug therapies focused on these intact processes. Several recent studies have…

Aging and emotional memory: the co-occurrence of neurophysiological and behavioral positivity effects.

PubMed

Langeslag, Sandra J E; van Strien, Jan W

2009-06-01

The positivity effect is a trend for adults to increasingly process positive and/or decreasingly process negative information compared with other information with advancing age. The positivity effect has been observed with behavioral measures, such as in attention and memory tests, and with measures of neurophysiological activity, such as in amygdala activation and the late positive potential (LPP). In this study, it was investigated whether these behavioral and neurophysiological positivity effects co-occur. The electroencephalogram of younger (19-26 years) and older (65-82 years) adults was recorded while they encoded unpleasant, neutral, and pleasant pictures for retrieval in free and cued recall tests. Positivity effects occurred in the late LPP amplitude (700-1,000 ms) and in the free recall test, with negativity biases in younger adults and no biases in older adults. The occurrence of a valence bias in the LPP was substantially but nonsignificantly correlated with the occurrence of a similar valence bias in memory in the older adults. In conclusion, neurophysiological and behavioral positivity effects appear to co-occur, a finding that awaits expansion using different neurophysiological and behavioral measures.

Memory retrieval and the passage of time: from reconsolidation and strengthening to extinction

PubMed Central

Inda, Maria Carmen; Muravieva, Elizaveta V.; Alberini, Cristina M.

2011-01-01

An established memory can be made transiently labile if retrieved or reactivated. Over time, it becomes again resistant to disruption and this process that renders the memory stable is termed reconsolidation. The reasons why a memory becomes labile after retrieval and reconsolidates still remains debated. Here, using inhibitory avoidance (IA) learning in rats, we provide evidence that retrievals of a young memory, which are accompanied by its reconsolidation, result in memory strengthening and contribute to its overall consolidation. This function associated to reconsolidation is temporally limited. With the passage of time, the stored memory undergoes important changes, as revealed by the behavioral outcomes of its retrieval. Over time, without explicit retrievals, memory first strengthens and becomes refractory to both retrieval-dependent interference and strengthening. At later times, the same retrievals that lead to reconsolidation of a young memory extinguish an older memory. We conclude that the storage of information is very dynamic and that its temporal evolution regulates behavioral outcomes. These results are important for potential clinical applications. PMID:21289172

Short-memory traders and their impact on group learning in financial markets

PubMed Central

LeBaron, Blake

2002-01-01

This article highlights several issues from simulating agent-based financial markets. These all center around the issue of learning in a multiagent setting, and specifically the question of whether the trading behavior of short-memory agents could interfere with the learning process of the market as whole. It is shown in a simple example that short-memory traders persist in generating excess volatility and other features common to actual markets. Problems related to short-memory trader behavior can be eliminated by using several different methods. These are discussed along with their relevance to agent-based models in general. PMID:11997443

A Randomized Clinical Trial Comparing Affect Regulation and Social Problem-Solving Psychotherapies for Mothers with Victimization-Related PTSD

ERIC Educational Resources Information Center

Ford, Julian D.; Steinberg, Karen L.; Zhang, Wanli

2011-01-01

Addressing affect dysregulation may provide a complementary alternative or adjunctive approach to the empirically supported trauma memory processing models of cognitive behavior therapy (CBT) for posttraumatic stress disorder (PTSD). A CBT designed to enhance affect regulation without trauma memory processing--trauma affect regulation: guide for…

Modeling aspects of human memory for scientific study.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Caudell, Thomas P.; Watson, Patrick; McDaniel, Mark A.

Working with leading experts in the field of cognitive neuroscience and computational intelligence, SNL has developed a computational architecture that represents neurocognitive mechanisms associated with how humans remember experiences in their past. The architecture represents how knowledge is organized and updated through information from individual experiences (episodes) via the cortical-hippocampal declarative memory system. We compared the simulated behavioral characteristics with those of humans measured under well established experimental standards, controlling for unmodeled aspects of human processing, such as perception. We used this knowledge to create robust simulations of & human memory behaviors that should help move the scientific community closermore » to understanding how humans remember information. These behaviors were experimentally validated against actual human subjects, which was published. An important outcome of the validation process will be the joining of specific experimental testing procedures from the field of neuroscience with computational representations from the field of cognitive modeling and simulation.« less

Oscillatory dynamics and place field maps reflect hippocampal ensemble processing of sequence and place memory under NMDA receptor control.

PubMed

Cabral, Henrique O; Vinck, Martin; Fouquet, Celine; Pennartz, Cyriel M A; Rondi-Reig, Laure; Battaglia, Francesco P

2014-01-22

Place coding in the hippocampus requires flexible combination of sensory inputs (e.g., environmental and self-motion information) with memory of past events. We show that mouse CA1 hippocampal spatial representations may either be anchored to external landmarks (place memory) or reflect memorized sequences of cell assemblies depending on the behavioral strategy spontaneously selected. These computational modalities correspond to different CA1 dynamical states, as expressed by theta and low- and high-frequency gamma oscillations, when switching from place to sequence memory-based processing. These changes are consistent with a shift from entorhinal to CA3 input dominance on CA1. In mice with a deletion of forebrain NMDA receptors, the ability of place cells to maintain a map based on sequence memory is selectively impaired and oscillatory dynamics are correspondingly altered, suggesting that oscillations contribute to selecting behaviorally appropriate computations in the hippocampus and that NMDA receptors are crucial for this function. Copyright © 2014 Elsevier Inc. All rights reserved.

Memory-updating abrogates extinction of learned immunosuppression.

PubMed

Hadamitzky, Martin; Bösche, Katharina; Wirth, Timo; Buck, Benjamin; Beetz, Oliver; Christians, Uwe; Schniedewind, Björn; Lückemann, Laura; Güntürkün, Onur; Engler, Harald; Schedlowski, Manfred

2016-02-01

When memories are recalled, they enter a transient labile phase in which they can be impaired or enhanced followed by a new stabilization process termed reconsolidation. It is unknown, however, whether reconsolidation is restricted to neurocognitive processes such as fear memories or can be extended to peripheral physiological functions as well. Here, we show in a paradigm of behaviorally conditioned taste aversion in rats memory-updating in learned immunosuppression. The administration of sub-therapeutic doses of the immunosuppressant cyclosporin A together with the conditioned stimulus (CS/saccharin) during retrieval blocked extinction of conditioned taste aversion and learned suppression of T cell cytokine (interleukin-2; interferon-γ) production. This conditioned immunosuppression is of clinical relevance since it significantly prolonged the survival time of heterotopically transplanted heart allografts in rats. Collectively, these findings demonstrate that memories can be updated on both neural and behavioral levels as well as on the level of peripheral physiological systems such as immune functioning. Copyright © 2015 Elsevier Inc. All rights reserved.

Depth, Spread, and Congruence of Encoding in Memory

DTIC Science & Technology

1980-08-01

Alternatively, Craik and Lockhart proposed a more parsimonious frame- work for research based on a levels -of- processing approach. They assumed that the...44. Craik , F. I. M., & Lockhart , R. S. Levels of processing : A framework for memory research. Journal of Verbal Learning and Verbal Behavior, 1972, 11...the basic concepts of the depth-of- processing or domains-of- processing ( Lockhart , Craik , & Jacoby, 1976) framework, suggesting that qualitative

Long-Term Aftereffects of Response Inhibition: Memory Retrieval, Task Goals, and Cognitive Control

ERIC Educational Resources Information Center

Verbruggen, Frederick; Logan, Gordon D.

2008-01-01

Cognitive control theories attribute control to executive processes that adjust and control behavior online. Theories of automaticity attribute control to memory retrieval. In the present study, online adjustments and memory retrieval were examined, and their roles in controlling performance in the stop-signal paradigm were elucidated. There was…

Behavioral Indications of Auditory Processing Disorders.

ERIC Educational Resources Information Center

Hartman, Kerry McGoldrick

1988-01-01

Identifies disruptive behaviors of children that may indicate central auditory processing disorders (CAPDs), perceptual handicaps of auditory discrimination or auditory memory not related to hearing ability. Outlines steps to modify the communication environment for CAPD children at home and in the classroom. (SV)

An ERP study of recognition memory for concrete and abstract pictures in school-aged children

PubMed Central

Boucher, Olivier; Chouinard-Leclaire, Christine; Muckle, Gina; Westerlund, Alissa; Burden, Matthew J.; Jacobson, Sandra W.; Jacobson, Joseph L.

2016-01-01

Recognition memory for concrete, nameable pictures is typically faster and more accurate than for abstract pictures. A dual-coding account for these findings suggests that concrete pictures are processed into verbal and image codes, whereas abstract pictures are encoded in image codes only. Recognition memory relies on two successive and distinct processes, namely familiarity and recollection. Whether these two processes are similarly or differently affected by stimulus concreteness remains unknown. This study examined the effect of picture concreteness on visual recognition memory processes using event-related potentials (ERPs). In a sample of children involved in a longitudinal study, participants (N = 96; mean age = 11.3 years) were assessed on a continuous visual recognition memory task in which half the pictures were easily nameable, everyday concrete objects, and the other half were three-dimensional abstract, sculpture-like objects. Behavioral performance and ERP correlates of familiarity and recollection (respectively, the FN400 and P600 repetition effects) were measured. Behavioral results indicated faster and more accurate identification of concrete pictures as “new” or “old” (i.e., previously displayed) compared to abstract pictures. ERPs were characterised by a larger repetition effect, on the P600 amplitude, for concrete than for abstract images, suggesting a graded recollection process dependant on the type of material to be recollected. Topographic differences were observed within the FN400 latency interval, especially over anterior-inferior electrodes, with the repetition effect more pronounced and localized over the left hemisphere for concrete stimuli, potentially reflecting different neural processes underlying early processing of verbal/semantic and visual material in memory. PMID:27329352

Generalized memory associativity in a network model for the neuroses

NASA Astrophysics Data System (ADS)

Wedemann, Roseli S.; Donangelo, Raul; de Carvalho, Luís A. V.

2009-03-01

We review concepts introduced in earlier work, where a neural network mechanism describes some mental processes in neurotic pathology and psychoanalytic working-through, as associative memory functioning, according to the findings of Freud. We developed a complex network model, where modules corresponding to sensorial and symbolic memories interact, representing unconscious and conscious mental processes. The model illustrates Freud's idea that consciousness is related to symbolic and linguistic memory activity in the brain. We have introduced a generalization of the Boltzmann machine to model memory associativity. Model behavior is illustrated with simulations and some of its properties are analyzed with methods from statistical mechanics.

Memory expression is independent of memory labilization/reconsolidation.

PubMed

Barreiro, Karina A; Suárez, Luis D; Lynch, Victoria M; Molina, Víctor A; Delorenzi, Alejandro

2013-11-01

There is growing evidence that certain reactivation conditions restrict the onset of both the destabilization phase and the restabilization process or reconsolidation. However, it is not yet clear how changes in memory expression during the retrieval experience can influence the emergence of the labilization/reconsolidation process. To address this issue, we used the context-signal memory model of Chasmagnathus. In this paradigm a short reminder that does not include reinforcement allows us to evaluate memory labilization and reconsolidation, whereas a short but reinforced reminder restricts the onset of such a process. The current study investigated the effects of the glutamate antagonists, APV (0.6 or 1.5 μg/g) and CNQX (1 μg/g), prior to the reminder session on both behavioral expression and the reconsolidation process. Under conditions where the reminder does not initiate the labilization/reconsolidation process, APV prevented memory expression without affecting long-term memory retention. In contrast, APV induced amnesic effects in the long-term when administered before a reminder session that triggers reconsolidation. Under the present parametric conditions, the administration of CNQX prior to the reminder that allows memory to enter reconsolidation impairs this process without disrupting memory expression. Overall, the present findings suggest that memory reactivation--but not memory expression--is necessary for labilization and reconsolidation. Retrieval and memory expression therefore appear not to be interchangeable concepts. Copyright © 2013 Elsevier Inc. All rights reserved.

Updating Procedures Can Reorganize the Neural Circuit Supporting a Fear Memory.

PubMed

Kwapis, Janine L; Jarome, Timothy J; Ferrara, Nicole C; Helmstetter, Fred J

2017-07-01

Established memories undergo a period of vulnerability following retrieval, a process termed 'reconsolidation.' Recent work has shown that the hypothetical process of reconsolidation is only triggered when new information is presented during retrieval, suggesting that this process may allow existing memories to be modified. Reconsolidation has received increasing attention as a possible therapeutic target for treating disorders that stem from traumatic memories, yet little is known about how this process changes the original memory. In particular, it is unknown whether reconsolidation can reorganize the neural circuit supporting an existing memory after that memory is modified with new information. Here, we show that trace fear memory undergoes a protein synthesis-dependent reconsolidation process following exposure to a single updating trial of delay conditioning. Further, this reconsolidation-dependent updating process appears to reorganize the neural circuit supporting the trace-trained memory, so that it better reflects the circuit supporting delay fear. Specifically, after a trace-to-delay update session, the amygdala is now required for extinction of the updated memory but the retrosplenial cortex is no longer required for retrieval. These results suggest that updating procedures could be used to force a complex, poorly defined memory circuit to rely on a better-defined neural circuit that may be more amenable to behavioral or pharmacological manipulation. This is the first evidence that exposure to new information can fundamentally reorganize the neural circuit supporting an existing memory.

THE COGNITIVE NEUROSCIENCE OF WORKING MEMORY

PubMed Central

D’Esposito, Mark; Postle, Bradley R.

2015-01-01

For over 50 years, psychologists and neuroscientists have recognized the importance of a “working memory” to coordinate processing when multiple goals are active, and to guide behavior with information that is not present in the immediate environment. In recent years, psychological theory and cognitive neuroscience data have converged on the idea that information is encoded into working memory via the allocation of attention to internal representations – be they semantic long-term memory (e.g., letters, digits, words), sensory, or motoric. Thus, information-based multivariate analyses of human functional MRI data typically find evidence for the temporary representation of stimuli in regions that also process this information in nonworking-memory contexts. The prefrontal cortex, on the other hand, exerts control over behavior by biasing the salience of mnemonic representations, and adjudicating among competing, context-dependent rules. The “control of the controller” emerges from a complex interplay between PFC and striatal circuits, and ascending dopaminergic neuromodulatory signals. PMID:25251486

Working Memory Load and Negative Picture Processing: Neural and Behavioral Associations With Panic, Social Anxiety, and Positive Affect.

PubMed

MacNamara, Annmarie; Jackson, T Bryan; Fitzgerald, Jacklynn M; Hajcak, Greg; Phan, K Luan

2018-04-22

Internalizing disorders such as anxiety may be characterized by an imbalance between bottom-up (stimulus-driven) and top-down (goal-directed) attention. The late positive potential (LPP) can be used to assess these processes when task-irrelevant negative and neutral pictures are presented within a working memory paradigm. Prior work using this paradigm has found that working memory load reduces the picture-elicited LPP across participants; however, anxious individuals showed a reduced effect of working memory load on the LPP, suggesting increased distractibility. The current study assessed transdiagnostic associations between specific symptom dimensions of anxiety, the LPP, and behavior in a clinically representative, heterogeneous group of 76 treatment-seeking patients with internalizing disorders, who performed a working memory task interspersed with negative and neutral pictures. As expected, negative pictures enhanced the LPP, and working memory load reduced the LPP. Participants with higher social anxiety showed increased LPPs to negative stimuli during early and late portions of picture presentation. Panic symptoms were associated with reduced LPPs to negative pictures compared with neutral pictures as well as a reduced effect of working memory load on the LPP during the late time window. Reduced positive affect was associated with greater behavioral interference from negative pictures. Hypervigilance for negative stimuli was uniquely explained by social anxiety symptoms, whereas panic symptoms were associated with the opposing effect-blunted processing/avoidance of these stimuli. Panic symptoms were uniquely associated with reduced top-down control. Results reveal distinct associations between neural reactivity and anxiety symptom dimensions that transcend traditional diagnostic boundaries. Copyright © 2018 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

Left-frontal brain potentials index conceptual implicit memory for words initially viewed subliminally.

PubMed

Chen, Jason C W; Li, Wen; Lui, Ming; Paller, Ken A

2009-08-18

Neural correlates of explicit and implicit memory tend to co-occur and are therefore difficult to measure independently, posing problems for understanding the unique nature of different types of memory processing. To circumvent this problem, we developed an experimental design wherein subjects acquired information from words presented in a subliminal manner, such that conscious remembering was minimized. Cross-modal word repetition was used so that perceptual implicit memory would also be limited. Healthy human subjects viewed subliminal words six times each and about 2 min later heard the same words interspersed with new words in a category-verification test. Electrophysiological correlates of word repetition included negative brain potentials over left-frontal locations beginning approximately 500 ms after word onset. Behavioral responses were slower for repeated words than for new words. Differential processing of word meaning in the absence of explicit memory was most likely responsible for differential electrical and behavioral responses to old versus new words. Moreover, these effects were distinct from neural correlates of explicit memory observed in prior experiments, and were observed here in two separate experiments, thus providing a foundation for further investigations of relationships and interactions between different types of memory engaged when words repeat.

Cognitive and neural consequences of memory suppression in major depressive disorder.

PubMed

Sacchet, Matthew D; Levy, Benjamin J; Hamilton, J Paul; Maksimovskiy, Arkadiy; Hertel, Paula T; Joormann, Jutta; Anderson, Michael C; Wagner, Anthony D; Gotlib, Ian H

2017-02-01

Negative biases in cognition have been documented consistently in major depressive disorder (MDD), including difficulties in the ability to control the processing of negative material. Although negative information-processing biases have been studied using both behavioral and neuroimaging paradigms, relatively little research has been conducted examining the difficulties of depressed persons with inhibiting the retrieval of negative information from long-term memory. In this study, we used the think/no-think paradigm and functional magnetic resonance imaging to assess the cognitive and neural consequences of memory suppression in individuals diagnosed with depression and in healthy controls. The participants showed typical behavioral forgetting effects, but contrary to our hypotheses, there were no differences between the depressed and nondepressed participants or between neutral and negative memories. Relative to controls, depressed individuals exhibited greater activity in right middle frontal gyrus during memory suppression, regardless of the valence of the suppressed stimuli, and differential activity in the amygdala and hippocampus during memory suppression involving negatively valenced stimuli. These findings indicate that depressed individuals are characterized by neural anomalies during the suppression of long-term memories, increasing our understanding of the brain bases of negative cognitive biases in MDD.

Gender differences in memory processing of female facial attractiveness: evidence from event-related potentials.

PubMed

Zhang, Yan; Wei, Bin; Zhao, Peiqiong; Zheng, Minxiao; Zhang, Lili

2016-06-01

High rates of agreement in the judgment of facial attractiveness suggest universal principles of beauty. This study investigated gender differences in recognition memory processing of female facial attractiveness. Thirty-four Chinese heterosexual participants (17 females, 17 males) aged 18-24 years (mean age 21.63 ± 1.51 years) participated in the experiment which used event-related potentials (ERPs) based on a study-test paradigm. The behavioral data results showed that both men and women had significantly higher accuracy rates for attractive faces than for unattractive faces, but men reacted faster to unattractive faces. Gender differences on ERPs showed that attractive faces elicited larger early components such as P1, N170, and P2 in men than in women. The results indicated that the effects of recognition bias during memory processing modulated by female facial attractiveness are greater for men than women. Behavioral and ERP evidences indicate that men and women differ in their attentional adhesion to attractive female faces; different mating-related motives may guide the selective processing of attractive men and women. These findings establish a contribution of gender differences on female facial attractiveness during memory processing from an evolutionary perspective.

Females scan more than males: a potential mechanism for sex differences in recognition memory.

PubMed

Heisz, Jennifer J; Pottruff, Molly M; Shore, David I

2013-07-01

Recognition-memory tests reveal individual differences in episodic memory; however, by themselves, these tests provide little information regarding the stage (or stages) in memory processing at which differences are manifested. We used eye-tracking technology, together with a recognition paradigm, to achieve a more detailed analysis of visual processing during encoding and retrieval. Although this approach may be useful for assessing differences in memory across many different populations, we focused on sex differences in face memory. Females outperformed males on recognition-memory tests, and this advantage was directly related to females' scanning behavior at encoding. Moreover, additional exposures to the faces reduced sex differences in face recognition, which suggests that males may be able to improve their recognition memory by extracting more information at encoding through increased scanning. A strategy of increased scanning at encoding may prove to be a simple way to enhance memory performance in other populations with memory impairment.

Auditory memory function in expert chess players.

PubMed

Fattahi, Fariba; Geshani, Ahmad; Jafari, Zahra; Jalaie, Shohreh; Salman Mahini, Mona

2015-01-01

Chess is a game that involves many aspects of high level cognition such as memory, attention, focus and problem solving. Long term practice of chess can improve cognition performances and behavioral skills. Auditory memory, as a kind of memory, can be influenced by strengthening processes following long term chess playing like other behavioral skills because of common processing pathways in the brain. The purpose of this study was to evaluate the auditory memory function of expert chess players using the Persian version of dichotic auditory-verbal memory test. The Persian version of dichotic auditory-verbal memory test was performed for 30 expert chess players aged 20-35 years and 30 non chess players who were matched by different conditions; the participants in both groups were randomly selected. The performance of the two groups was compared by independent samples t-test using SPSS version 21. The mean score of dichotic auditory-verbal memory test between the two groups, expert chess players and non-chess players, revealed a significant difference (p≤ 0.001). The difference between the ears scores for expert chess players (p= 0.023) and non-chess players (p= 0.013) was significant. Gender had no effect on the test results. Auditory memory function in expert chess players was significantly better compared to non-chess players. It seems that increased auditory memory function is related to strengthening cognitive performances due to playing chess for a long time.

Experimental study of thermo-mechanical behavior of a thermosetting shape-memory polymer

NASA Astrophysics Data System (ADS)

Liu, Ruoxuan; Li, Yunxin; Liu, Zishun

2018-01-01

The thermo-mechanical behavior of shape-memory polymers (SMPs) serves for the engineering applications of SMPs. Therefore the understanding of thermo-mechanical behavior of SMPs is of great importance. This paper investigates the influence of loading rate and loading level on the thermo-mechanical behavior of a thermosetting shape-memory polymer through experimental study. A series of cyclic tension tests and shape recovery tests at different loading conditions are performed to study the strain level and strain rate effect. The results of tension tests show that the thermosetting shape-memory polymer will behave as rubber material at temperature lower than the glass transition temperature (Tg) and it can obtain a large shape fix ratio at cyclic loading condition. The shape recovery tests exhibit that loading rate and loading level have little effect on the beginning and ending of shape recovery process of the thermosetting shape-memory polymer. Compared with the material which is deformed at temperature higher than Tg, the material deformed at temperature lower than Tg behaves a bigger recovery speed.

Characterization of mechanical properties of pseudoelastic shape memory alloys under harmonic excitation

NASA Astrophysics Data System (ADS)

Böttcher, J.; Jahn, M.; Tatzko, S.

2017-12-01

Pseudoelastic shape memory alloys exhibit a stress-induced phase transformation which leads to high strains during deformation of the material. The stress-strain characteristic during this thermomechanical process is hysteretic and results in the conversion of mechanical energy into thermal energy. This energy conversion allows for the use of shape memory alloys in vibration reduction. For the application of shape memory alloys as vibration damping devices a dynamic modeling of the material behavior is necessary. In this context experimentally determined material parameters which accurately represent the material behavior are essential for a reliable material model. Subject of this publication is the declaration of suitable material parameters for pseudoelastic shape memory alloys and the methodology of their identification from experimental investigations. The used test rig was specifically designed for the characterization of pseudoelastic shape memory alloys.

How cognitive theory guides neuroscience.

PubMed

Frank, Michael J; Badre, David

2015-02-01

The field of cognitive science studies latent, unobservable cognitive processes that generate observable behaviors. Similarly, cognitive neuroscience attempts to link latent cognitive processes with the neural mechanisms that generate them. Although neural processes are partially observable (with imaging and electrophysiology), it would be a mistake to 'skip' the cognitive level and pursue a purely neuroscientific enterprise to studying behavior. In fact, virtually all of the major advances in understanding the neural basis of behavior over the last century have relied fundamentally on principles of cognition for guiding the appropriate measurements, manipulations, tasks, and interpretations. We provide several examples from the domains of episodic memory, working memory and cognitive control, and decision making in which cognitive theorizing and prior experimentation has been essential in guiding neuroscientific investigations and discoveries. Copyright © 2014 Elsevier B.V. All rights reserved.

Episodic Memory in Former Professional Football Players with a History of Concussion: An Event-Related Functional Neuroimaging Study

PubMed Central

Giovanello, Kelly S.; Guskiewicz, Kevin M.

2013-01-01

Abstract Previous research has demonstrated that sport-related concussions can have short-term effects on cognitive processes, but the long-term consequences are less understood and warrant more research. This study was the first to use event-related functional magnetic resonance imaging (fMRI) to examine long-term differences in neural activity during memory tasks in former athletes who have sustained multiple sport-related concussions. In an event-related fMRI study, former football players reporting multiple sport-related concussions (i.e., three or more) were compared with players who reported fewer than three concussions during a memory paradigm examining item memory (i.e., memory for the particular elements of an event) and relational memory (i.e., memory for the relationships between elements). Behaviorally, we observed that concussion history did not significantly affect behavioral performance, because persons in the low and high concussion groups had equivalent performance on both memory tasks, and in addition, that concussion history was not associated with any behavioral memory measures. Despite demonstrating equivalent behavioral performance, the two groups of former players demonstrated different neural recruitment patterns during relational memory retrieval, suggesting that multiple concussions may be associated with functional inefficiencies in the relational memory network. In addition, the number of previous concussions significantly correlated with functional activity in a number of brain regions, including the medial temporal lobe and inferior parietal lobe. Our results provide important insights in understanding the long-term functional consequences of sustaining multiple sports-related concussions. PMID:23679098

Dual-Task Processing as a Measure of Executive Function: A Comparison between Adults with Williams and Down Syndromes

ERIC Educational Resources Information Center

Kittler, Phyllis M.; Krinsky-McHale, Sharon J.; Devenny, Darlynne A.

2008-01-01

Behavioral phenotypes of individuals with Williams syndrome and individuals with Down syndrome have been contrasted in relation to short-term memory. People with Down syndrome are stronger visuospatially and those with Williams syndrome are stronger verbally. We examined short-term memory, then explored whether dual-task processing further…

Electrical Stimulation in Hippocampus and Entorhinal Cortex Impairs Spatial and Temporal Memory.

PubMed

Goyal, Abhinav; Miller, Jonathan; Watrous, Andrew J; Lee, Sang Ah; Coffey, Tom; Sperling, Michael R; Sharan, Ashwini; Worrell, Gregory; Berry, Brent; Lega, Bradley; Jobst, Barbara C; Davis, Kathryn A; Inman, Cory; Sheth, Sameer A; Wanda, Paul A; Ezzyat, Youssef; Das, Sandhitsu R; Stein, Joel; Gorniak, Richard; Jacobs, Joshua

2018-05-09

The medial temporal lobe (MTL) is widely implicated in supporting episodic memory and navigation, but its precise functional role in organizing memory across time and space remains elusive. Here we examine the specific cognitive processes implemented by MTL structures (hippocampus and entorhinal cortex) to organize memory by using electrical brain stimulation, leveraging its ability to establish causal links between brain regions and features of behavior. We studied neurosurgical patients of both sexes who performed spatial-navigation and verbal-episodic memory tasks while brain stimulation was applied in various regions during learning. During the verbal memory task, stimulation in the MTL disrupted the temporal organization of encoded memories such that items learned with stimulation tended to be recalled in a more randomized order. During the spatial task, MTL stimulation impaired subjects' abilities to remember items located far away from boundaries. These stimulation effects were specific to the MTL. Our findings thus provide the first causal demonstration in humans of the specific memory processes that are performed by the MTL to encode when and where events occurred. SIGNIFICANCE STATEMENT Numerous studies have implicated the medial temporal lobe (MTL) in encoding spatial and temporal memories, but they have not been able to causally demonstrate the nature of the cognitive processes by which this occurs in real-time. Electrical brain stimulation is able to demonstrate causal links between a brain region and a given function with high temporal precision. By examining behavior in a memory task as subjects received MTL stimulation, we provide the first causal evidence demonstrating the role of the MTL in organizing the spatial and temporal aspects of episodic memory. Copyright © 2018 the authors 0270-6474/18/384471-11$15.00/0.

Working Memory Deficits in Boys with Attention-Deficit/Hyperactivity Disorder (ADHD): The Contribution of Central Executive and Subsystem Processes

ERIC Educational Resources Information Center

Rapport, Mark D.; Alderson, R. Matt; Kofler, Michael J.; Sarver, Dustin E.; Bolden, Jennifer; Sims, Valerie

2008-01-01

The current study investigated contradictory findings from recent experimental and meta-analytic studies concerning working memory deficits in ADHD. Working memory refers to the cognitive ability to temporarily store and mentally manipulate limited amounts of information for use in guiding behavior. Phonological (verbal) and visuospatial…

The Effects of Incentives on Visual-Spatial Working Memory in Children with Attention-Deficit/Hyperactivity Disorder

ERIC Educational Resources Information Center

Shiels, Keri; Hawk, Larry W., Jr.; Lysczek, Cynthia L.; Tannock, Rosemary; Pelham, William E., Jr.; Spencer, Sarah V.; Gangloff, Brian P.; Waschbusch, Daniel A.

2008-01-01

Working memory is one of several putative core neurocognitive processes in attention-deficit/hyperactivity disorder (ADHD). The present work seeks to determine whether visual-spatial working memory is sensitive to motivational incentives, a laboratory analogue of behavioral treatment. Participants were 21 children (ages 7-10) with a diagnosis of…

Inattentive Behavior in Boys with ADHD during Classroom Instruction: the Mediating Role of Working Memory Processes.

PubMed

Orban, Sarah A; Rapport, Mark D; Friedman, Lauren M; Eckrich, Samuel J; Kofler, Michael J

2018-05-01

Children with ADHD exhibit clinically impairing inattentive behavior during classroom instruction and in other cognitively demanding contexts. However, there have been surprisingly few attempts to validate anecdotal parent/teacher reports of intact sustained attention during 'preferred' activities such as watching movies. The current investigation addresses this omission, and provides an initial test of how ADHD-related working memory deficits contribute to inattentive behavior during classroom instruction. Boys ages 8-12 (M = 9.62, SD = 1.22) with ADHD (n = 32) and typically developing boys (TD; n = 30) completed a counterbalanced series of working memory tests and watched two videos on separate assessment days: an analogue math instructional video, and a non-instructional video selected to match the content and cognitive demands of parent/teacher-described 'preferred' activities. Objective, reliable observations of attentive behavior revealed no between-group differences during the non-instructional video (d = -0.02), and attentive behavior during the non-instructional video was unrelated to all working memory variables (r = -0.11 to 0.19, ns). In contrast, the ADHD group showed disproportionate attentive behavior decrements during analogue classroom instruction (d = -0.71). Bias-corrected, bootstrapped, serial mediation revealed that 59% of this between-group difference was attributable to ADHD-related impairments in central executive working memory, both directly (ER = 41%) and indirectly via its role in coordinating phonological short-term memory (ER = 15%). Between-group attentive behavior differences were no longer detectable after accounting for ADHD-related working memory impairments (d = -0.29, ns). Results confirm anecdotal reports of intact sustained attention during activities that place minimal demands on working memory, and indicate that ADHD children's inattention during analogue classroom instruction is related, in large part, to their underdeveloped working memory abilities.

The impact of imprisonment on overgeneral autobiographical memory in former political prisoners.

PubMed

Kleim, Birgit; Griffith, James W; Gäbler, Ira; Schützwohl, Matthias; Maercker, Andreas

2013-10-01

Traumatic experiences may dramatically influence later behavior and cognitive processing. This study investigated how trauma shapes the way that we remember personal experiences. Specifically, we investigated overgeneral autobiographical memory, which is the tendency to remember autobiographical events in an overgeneral rather than specific way. We administered the Autobiographical Memory Test (Williams & Broadbent,) to 86 survivors of political imprisonment 37 years after they had been released from imprisonment. Depression and posttraumatic stress disorder were not significantly related to overgeneral autobiographical memory. Significant overgeneral autobiographical memory correlates included embitterment, r = -.28, and being released to former East Germany, d = 0.67. Survivors with social support, r = .30 were better able to recall specific memories. Certain trauma characteristics and the way the trauma is processed may thus influence how personal memories are later remembered. This study also furthers the understanding of memory processes in political prisoners, who are not commonly studied in psychological research. Copyright © 2013 International Society for Traumatic Stress Studies.

An Abrupt Transformation of Phobic Behavior After a Post-Retrieval Amnesic Agent.

PubMed

Soeter, Marieke; Kindt, Merel

2015-12-15

Although disrupting the process of memory reconsolidation has a great potential for clinical practice, the fear-amnesic effects are typically demonstrated through Pavlovian conditioning. Given that older and stronger memories are generally more resistant to change, we tested whether disrupting reconsolidation would also diminish fear in individuals who had developed a persistent spider fear outside the laboratory. Spider-fearful participants received a single dose of 40 mg of the noradrenergic β-blocker propranolol (n = 15), double-blind and placebo-controlled (n = 15), after a short 2-min exposure to a tarantula. To test whether memory reactivation was necessary to observe a fear-reducing effect, one additional group of spider-fearful participants (n = 15) received a single dose of 40 mg propranolol without memory reactivation. Disrupting reconsolidation of fear memory transformed avoidance behavior into approach behavior in a virtual binary fashion-an effect that persisted at least 1 year after treatment. Interestingly the β-adrenergic drug did initially not affect the self-declared fear of spiders but instead these reports followed the instant behavioral transformation several months later. Our findings are in sharp contrast with the currently pharmacological and cognitive behavioral treatments for anxiety and related disorders. The β-adrenergic blocker was only effective when the drug was administered upon memory reactivation, and a modification in cognitive representations was not necessary to observe a change in fear behavior. A new wave of treatments that pharmacologically target the synaptic plasticity underlying learning and memory seems to be within reach. Copyright © 2015 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

Strategy-Selection in Question-Answering.

DTIC Science & Technology

1985-10-03

34 form of "perceptual learning." They note that levels of processing (See Craik & Lockhart , 1972) affect recognition memory but not perceptual... Craik , F. I. M., & Lockhart , R. S. (1972). Levels of processing : A framework for memory research. Journal of Verbal Learning and Verbal Behavior, 11...practice, subjects seemed able to achieve higher levels of performance on both tasks. One possibility they consider is that the processes involved *. in the

Memory for angry faces, impulsivity, and problematic behavior in adolescence.

PubMed

d'Acremont, Mathieu; Van der Linden, Martial

2007-04-01

Research has shown that cognitive processes like the attribution of hostile intention or angry emotion to others contribute to the development and maintenance of conduct problems. However, the role of memory has been understudied in comparison with attribution biases. The aim of this study was thus to test if a memory bias for angry faces was related to conduct problems in youth. Adolescents from a junior secondary school were presented with angry and happy faces and were later asked to recognize the same faces with a neutral expression. They also completed an impulsivity questionnaire. A teacher assessed their behavior. The results showed that a better recognition of angry faces than happy faces predicted conduct problems and hyperactivity/inattention as reported by the teacher. The memory bias effect was more pronounced for impulsive adolescents. It is suggested that a memory bias for angry faces favors disruptive behavior but that a good ability to control impulses may moderate the negative impact of this bias.

Statistical prediction with Kanerva's sparse distributed memory

NASA Technical Reports Server (NTRS)

Rogers, David

1989-01-01

A new viewpoint of the processing performed by Kanerva's sparse distributed memory (SDM) is presented. In conditions of near- or over-capacity, where the associative-memory behavior of the model breaks down, the processing performed by the model can be interpreted as that of a statistical predictor. Mathematical results are presented which serve as the framework for a new statistical viewpoint of sparse distributed memory and for which the standard formulation of SDM is a special case. This viewpoint suggests possible enhancements to the SDM model, including a procedure for improving the predictiveness of the system based on Holland's work with genetic algorithms, and a method for improving the capacity of SDM even when used as an associative memory.

An ERP study of recognition memory for concrete and abstract pictures in school-aged children.

PubMed

Boucher, Olivier; Chouinard-Leclaire, Christine; Muckle, Gina; Westerlund, Alissa; Burden, Matthew J; Jacobson, Sandra W; Jacobson, Joseph L

2016-08-01

Recognition memory for concrete, nameable pictures is typically faster and more accurate than for abstract pictures. A dual-coding account for these findings suggests that concrete pictures are processed into verbal and image codes, whereas abstract pictures are encoded in image codes only. Recognition memory relies on two successive and distinct processes, namely familiarity and recollection. Whether these two processes are similarly or differently affected by stimulus concreteness remains unknown. This study examined the effect of picture concreteness on visual recognition memory processes using event-related potentials (ERPs). In a sample of children involved in a longitudinal study, participants (N=96; mean age=11.3years) were assessed on a continuous visual recognition memory task in which half the pictures were easily nameable, everyday concrete objects, and the other half were three-dimensional abstract, sculpture-like objects. Behavioral performance and ERP correlates of familiarity and recollection (respectively, the FN400 and P600 repetition effects) were measured. Behavioral results indicated faster and more accurate identification of concrete pictures as "new" or "old" (i.e., previously displayed) compared to abstract pictures. ERPs were characterized by a larger repetition effect, on the P600 amplitude, for concrete than for abstract images, suggesting a graded recollection process dependent on the type of material to be recollected. Topographic differences were observed within the FN400 latency interval, especially over anterior-inferior electrodes, with the repetition effect more pronounced and localized over the left hemisphere for concrete stimuli, potentially reflecting different neural processes underlying early processing of verbal/semantic and visual material in memory. Copyright © 2016 Elsevier B.V. All rights reserved.

Palmitoylethanolamide Modulates GPR55 Receptor Signaling in the Ventral Hippocampus to Regulate Mesolimbic Dopamine Activity, Social Interaction, and Memory Processing.

PubMed

Kramar, Cecilia; Loureiro, Michael; Renard, Justine; Laviolette, Steven R

2017-01-01

Introduction: The GPR55 receptor has been identified as an atypical cannabinoid receptor and is implicated in various physiological processes. However, its functional role in the central nervous system is not currently understood. The presence of GPR55 receptor in neural regions such as the ventral hippocampus (vHipp), which is critical for cognition, recognition memory, and affective processing, led us to hypothesize that intra-vHipp GPR55 transmission may modulate mesolimbic activity states and related behavioral phenomena. The vHipp is involved in contextual memory and affective regulation through functional interactions with the mesolimbic dopamine system. Materials and Methods: Using a combination of in vivo electrophysiology and behavioral pharmacological assays in rats, we tested whether intra-vHipp activation of GPR55 receptor transmission with the fatty acid amide, palmitoylethanolamide (PEA), a lipid neuromodulator with agonist actions at the GPR55 receptor, may modulate mesolimbic dopaminergic activity states. We further examined the potential effects of intra-vHipp PEA in affective, cognitive and contextual memory tasks. Discussion: We report that intra-vHipp PEA produces a hyper-dopaminergic state in the mesolimbic system characterized by increased firing and bursting activity of ventral tegmental area dopaminergic neuron populations. Furthermore, while PEA-induced activation of GPR55 transmission had no effects on opiate-related reward-related memory formation, we observed strong disruptions in social interaction and recognition memory, spatial location memory, and context-independent associative fear memory formation. Finally, the effects of intra-vHipp PEA were blocked by a selective GPR55 receptor antagonist, CID160 and were dependent upon NMDA receptor transmission, directly in the vHipp. Conclusions: The present results add to a growing body of evidence demonstrating important functional roles for GPR55 signaling in cannabinoid-related neuronal and behavioral phenomena and underscore the potential for GPR55 signaling in the mediation of cannabinoid-related effects independently of the CB1/CB2 receptor systems.

Hippocampal histone acetylation regulates object recognition and the estradiol-induced enhancement of object recognition

PubMed Central

Zhao, Zaorui; Fan, Lu; Fortress, Ashley M.; Boulware, Marissa I.; Frick, Karyn M.

2012-01-01

Histone acetylation has recently been implicated in learning and memory processes, yet necessity of histone acetylation for such processes has not been demonstrated using pharmacological inhibitors of histone acetyltransferases (HATs). As such, the present study tested whether garcinol, a potent HAT inhibitor in vitro, could impair hippocampal memory consolidation and block the memory-enhancing effects of the modulatory hormone 17β-estradiol (E2). We first showed that bilateral infusion of garcinol (0.1, 1, or 10 μg/side) into the dorsal hippocampus (DH) immediately after training impaired object recognition memory consolidation in ovariectomized female mice. A behaviorally effective dose of garcinol (10 μg/side) also significantly decreased DH HAT activity. We next examined whether DH infusion of a behaviorally subeffective dose of garcinol (1 ng/side) could block the effects of DH E2 infusion on object recognition and epigenetic processes. Immediately after training, ovariectomized female mice received bilateral DH infusions of vehicle, E2 (5 μg/side), garcinol (1 ng/side), or E2 plus garcinol. Forty-eight hours later, garcinol blocked the memory-enhancing effects of E2. Garcinol also reversed the E2-induced increase in DH histone H3 acetylation, HAT activity, and levels of the de novo methyltransferase DNMT3B, as well as the E2-induced decrease in levels of the memory repressor protein histone deacetylase 2 (HDAC2). Collectively, these findings suggest that histone acetylation is critical for object recognition memory consolidation and the beneficial effects of E2 on object recognition. Importantly, this work demonstrates that the role of histone acetylation in memory processes can be studied using a HAT inhibitor. PMID:22396409

Self-Regulation as an Aid to Human Effectiveness and Biocybernetics Technology and Behavior

DTIC Science & Technology

1976-01-01

feedback and two measures of information-processing capacity: short-term memory for digits and choice-reaction times. In this study, Beatty selected...Kamiya, like Beatty, found EEG activity unrelated to both memory for words and a simple reaction-time test. In another study, Kamiya (1972...creative intelligence, visual memory , mental arithmetic, digit memory span, and i,une tracking. The results were negative. Kamiya concluded that the self

The Duration of Auditory Sensory Memory for Vowel Processing: Neurophysiological and Behavioral Measures.

PubMed

Yu, Yan H; Shafer, Valerie L; Sussman, Elyse S

2018-01-01

Speech perception behavioral research suggests that rates of sensory memory decay are dependent on stimulus properties at more than one level (e.g., acoustic level, phonemic level). The neurophysiology of sensory memory decay rate has rarely been examined in the context of speech processing. In a lexical tone study, we showed that long-term memory representation of lexical tone slows the decay rate of sensory memory for these tones. Here, we tested the hypothesis that long-term memory representation of vowels slows the rate of auditory sensory memory decay in a similar way to that of lexical tone. Event-related potential (ERP) responses were recorded to Mandarin non-words contrasting the vowels /i/ vs. /u/ and /y/ vs. /u/ from first-language (L1) Mandarin and L1 American English participants under short and long interstimulus interval (ISI) conditions (short ISI: an average of 575 ms, long ISI: an average of 2675 ms). Results revealed poorer discrimination of the vowel contrasts for English listeners than Mandarin listeners, but with different patterns for behavioral perception and neural discrimination. As predicted, English listeners showed the poorest discrimination and identification for the vowel contrast /y/ vs. /u/, and poorer performance in the long ISI condition. In contrast to Yu et al. (2017), however, we found no effect of ISI reflected in the neural responses, specifically the mismatch negativity (MMN), P3a and late negativity ERP amplitudes. We did see a language group effect, with Mandarin listeners generally showing larger MMN and English listeners showing larger P3a. The behavioral results revealed that native language experience plays a role in echoic sensory memory trace maintenance, but the failure to find an effect of ISI on the ERP results suggests that vowel and lexical tone memory traces decay at different rates. Highlights : We examined the interaction between auditory sensory memory decay and language experience. We compared MMN, P3a, LN and behavioral responses in short vs. long interstimulus intervals. We found that different from lexical tone contrast, MMN, P3a, and LN changes to vowel contrasts are not influenced by lengthening the ISI to 2.6 s. We also found that the English listeners discriminated the non-native vowel contrast with lower accuracy under the long ISI condition.

Unipolar resistive switching behaviors and mechanisms in an annealed Ni/ZrO2/TaN memory device

NASA Astrophysics Data System (ADS)

Tsai, Tsung-Ling; Ho, Tsung-Han; Tseng, Tseung-Yuen

2015-01-01

The effects of Ni/ZrO2/TaN resistive switching memory devices without and with a 400 °C annealing process on switching properties are investigated. The devices exhibit unipolar resistive switching behaviors with low set and reset voltages because of a large amount of Ni diffusion with no reaction with ZrO2 after the annealing process, which is confirmed by ToF-SIMS and XPS analyses. A physical model based on a Ni filament is constructed to explain such phenomena. The device that undergoes the 400 °C annealing process exhibits an excellent endurance of more than 1.5  ×  104 cycles. The improvement can be attributed to the enhancement of oxygen ion migration along grain boundaries, which result in less oxygen ion consumption during the reset process. The device also performs good retention up to 105 s at 150 °C. Therefore, it has great potential for high-density nonvolatile memory applications.

Precipitation-induced of partial annealing of Ni-rich NiTi shape memory alloy

NASA Astrophysics Data System (ADS)

Nashrudin, Muhammad Naqib; Mahmud, Abdus Samad; Mohamad, Hishamiakim

2018-05-01

NiTi shape memory alloy behavior is very sensitive to alloy composition and heat treatment processes. Thermomechanical behavior of near-equiatomic alloy is normally enhanced by partial anneal of a cold-worked specimen. The shape memory behavior of Ni-rich alloy can be enhanced by ageing precipitation. This work studied the effect of simultaneous partial annealing and ageing precipitation of a Ni-rich cold drawn Ti-50.9at%Ni wire towards martensite phase transformation behavior. Ageing treatment of a non-cold worked specimen was also done for comparison. It was found that the increase of heat treatment temperature caused the forward transformation stress to decrease for the cold worked and non-cold worked specimens. Strain recovery on the reverse transformation of the cold worked wire improved compared to the non-cold worked wire as the temperature increased.

Confidence and the stock market: an agent-based approach.

PubMed

Bertella, Mario A; Pires, Felipe R; Feng, Ling; Stanley, Harry Eugene

2014-01-01

Using a behavioral finance approach we study the impact of behavioral bias. We construct an artificial market consisting of fundamentalists and chartists to model the decision-making process of various agents. The agents differ in their strategies for evaluating stock prices, and exhibit differing memory lengths and confidence levels. When we increase the heterogeneity of the strategies used by the agents, in particular the memory lengths, we observe excess volatility and kurtosis, in agreement with real market fluctuations--indicating that agents in real-world financial markets exhibit widely differing memory lengths. We incorporate the behavioral traits of adaptive confidence and observe a positive correlation between average confidence and return rate, indicating that market sentiment is an important driver in price fluctuations. The introduction of market confidence increases price volatility, reflecting the negative effect of irrationality in market behavior.

Confidence and the Stock Market: An Agent-Based Approach

PubMed Central

Bertella, Mario A.; Pires, Felipe R.; Feng, Ling; Stanley, Harry Eugene

2014-01-01

Using a behavioral finance approach we study the impact of behavioral bias. We construct an artificial market consisting of fundamentalists and chartists to model the decision-making process of various agents. The agents differ in their strategies for evaluating stock prices, and exhibit differing memory lengths and confidence levels. When we increase the heterogeneity of the strategies used by the agents, in particular the memory lengths, we observe excess volatility and kurtosis, in agreement with real market fluctuations—indicating that agents in real-world financial markets exhibit widely differing memory lengths. We incorporate the behavioral traits of adaptive confidence and observe a positive correlation between average confidence and return rate, indicating that market sentiment is an important driver in price fluctuations. The introduction of market confidence increases price volatility, reflecting the negative effect of irrationality in market behavior. PMID:24421888

Interplay between Hippocampal Sharp-Wave-Ripple Events and Vicarious Trial and Error Behaviors in Decision Making.

PubMed

Papale, Andrew E; Zielinski, Mark C; Frank, Loren M; Jadhav, Shantanu P; Redish, A David

2016-12-07

Current theories posit that memories encoded during experiences are subsequently consolidated into longer-term storage. Hippocampal sharp-wave-ripple (SWR) events have been linked to this consolidation process during sleep, but SWRs also occur during awake immobility, where their role remains unclear. We report that awake SWR rates at the reward site are inversely related to the prevalence of vicarious trial and error (VTE) behaviors, thought to be involved in deliberation processes. SWR rates were diminished immediately after VTE behaviors and an increase in the rate of SWR events at the reward site predicted a decrease in subsequent VTE behaviors at the choice point. Furthermore, SWR disruptions increased VTE behaviors. These results suggest an inverse relationship between SWRs and VTE behaviors and suggest that awake SWRs and associated planning and memory consolidation mechanisms are engaged specifically in the context of higher levels of behavioral certainty. Copyright © 2016 Elsevier Inc. All rights reserved.

Fear extinction and memory reconsolidation as critical components in behavioral treatment for posttraumatic stress disorder and potential augmentation of these processes.

PubMed

Smith, Noelle B; Doran, Jennifer M; Sippel, Lauren M; Harpaz-Rotem, Ilan

2017-05-10

Posttraumatic stress disorder (PTSD) is associated with alterations in critical brain regions such as the amygdala, hippocampus, and prefrontal cortex. This brief review has two objectives: (1) to discuss research examining extinction and reconsolidation processes as mechanisms in PTSD psychotherapy, and (2) present possibilities for augmenting extinction and reconsolidation within treatment through alterations to therapeutic interventions and novel approaches. A key component of many effective PTSD therapies is exposure, which involves intentional confrontation and processing of the traumatic memory. Our review suggests that extinction and reconsolidation processes underlie effective exposure-based treatment, but the neurobiological mechanisms of these processes in behavioral treatments for PTSD remains unclear. We argue that enhancing extinction and/or disrupting reconsolidation of a feared memory may improve the efficacy of existing treatments (e.g., increased change for limited/non-responders, faster/greater changes for responders), which can be done through multiple channels. Potential avenues for augmentation of the processes of extinction and reconsolidation in PTSD psychotherapies are reviewed, including behavioral modifications, pharmacotherapy agents, and the use of devices during therapy. We further suggest that investigations towards understanding the extent to which extinction and reconsolidation processes are necessary in effective PTSD psychotherapy is an important future direction for enhancing clinical care among PTSD populations. Published by Elsevier B.V.

Executive Functions Are Employed to Process Episodic and Relational Memories in Children With Autism Spectrum Disorders

PubMed Central

2013-01-01

Objective: Long-term memory functioning in autism spectrum disorders (ASDs) is marked by a characteristic pattern of impairments and strengths. Individuals with ASD show impairment in memory tasks that require the processing of relational and contextual information, but spared performance on tasks requiring more item-based, acontextual processing. Two experiments investigated the cognitive mechanisms underlying this memory profile. Method: A sample of 14 children with a diagnosis of high-functioning ASD (age: M = 12.2 years), and a matched control group of 14 typically developing (TD) children (age: M = 12.1 years), participated in a range of behavioral memory tasks in which we measured both relational and item-based memory abilities. They also completed a battery of executive function measures. Results: The ASD group showed specific deficits in relational memory, but spared or superior performance in item-based memory, across all tasks. Importantly, for ASD children, executive ability was significantly correlated with relational memory but not with item-based memory. No such relationship was present in the control group. This suggests that children with ASD atypically employed effortful, executive strategies to retrieve relational (but not item-specific) information, whereas TD children appeared to use more automatic processes. Conclusions: The relational memory impairment in ASD may result from a specific impairment in automatic associative retrieval processes with an increased reliance on effortful and strategic retrieval processes. Our findings allow specific neural predictions to be made regarding the interactive functioning of the hippocampus, prefrontal cortex, and posterior parietal cortex in ASD as a neural network supporting relational memory processing. PMID:24245930

Short-Term Memory: The "Storage" Component of Human Brain Responses Predicts Recall.

ERIC Educational Resources Information Center

Chapman, Robert M.; And Others

1978-01-01

Presents electrophysiological and behavioral evidence for a neural process related to storage in short-term memory. Predicting recall performance on the basis of the storage component of brain responses is presented. A list of references is also included. (HM)

A role for histone deacetylases in the cellular and behavioral mechanisms underlying learning and memory.

PubMed

Mahgoub, Melissa; Monteggia, Lisa M

2014-10-01

Histone deacetylases (HDACs) are a family of chromatin remodeling enzymes that restrict access of transcription factors to the DNA, thereby repressing gene expression. In contrast, histone acetyltransferases (HATs) relax the chromatin structure allowing for an active chromatin state and promoting gene transcription. Accumulating data have demonstrated a crucial function for histone acetylation and histone deacetylation in regulating the cellular and behavioral mechanisms underlying synaptic plasticity and learning and memory. In trying to delineate the roles of individual HDACs, genetic tools have been used to manipulate HDAC expression in rodents, uncovering distinct contributions of individual HDACs in regulating the processes of memory formation. Moreover, recent findings have suggested an important role for HDAC inhibitors in enhancing learning and memory processes as well as ameliorating symptoms related to neurodegenerative diseases. In this review, we focus on the role of HDACs in learning and memory, as well as significant data emerging from the field in support of HDAC inhibitors as potential therapeutic targets for the treatment of cognitive disorders. © 2014 Mahgoub and Monteggia; Published by Cold Spring Harbor Laboratory Press.

Is an epigenetic switch the key to persistent extinction?

PubMed Central

Stafford, James M.; Lattal, K. Matthew

2011-01-01

Many studies of learning have demonstrated that conditioned behavior can be eliminated when previously established relations between stimuli are severed. This extinction process has been extremely important for the development of learning theories and, more recently, for delineating the neurobiological mechanisms that underlie memory. A key finding from behavioral studies of extinction is that extinction eliminates behavior without eliminating the original memory; extinguished behavior often returns with time or with a return to the context in which the original learning occurred. This persistence of the original memory after extinction creates a challenge for clinical applications that use extinction as part of a treatment intervention. Consequently, a goal of recent neurobiological research on extinction is to identify potential pharmacological targets that may result in persistent extinction. Drugs that promote epigenetic changes are particularly promising because they can result in a long-term molecular signal that, combined with the appropriate behavioral treatment, can cause persistent changes in behavior induced by extinction. We will review evidence demonstrating extinction enhancements by drugs that target epigenetic mechanisms and will describe some of the challenges that epigenetic approaches face in promoting persistent suppression of memories. PMID:21536141

A general model for memory interference in a multiprocessor system with memory hierarchy

NASA Technical Reports Server (NTRS)

Taha, Badie A.; Standley, Hilda M.

1989-01-01

The problem of memory interference in a multiprocessor system with a hierarchy of shared buses and memories is addressed. The behavior of the processors is represented by a sequence of memory requests with each followed by a determined amount of processing time. A statistical queuing network model for determining the extent of memory interference in multiprocessor systems with clusters of memory hierarchies is presented. The performance of the system is measured by the expected number of busy memory clusters. The results of the analytic model are compared with simulation results, and the correlation between them is found to be very high.

Auditory memory function in expert chess players

PubMed Central

Fattahi, Fariba; Geshani, Ahmad; Jafari, Zahra; Jalaie, Shohreh; Salman Mahini, Mona

2015-01-01

Background: Chess is a game that involves many aspects of high level cognition such as memory, attention, focus and problem solving. Long term practice of chess can improve cognition performances and behavioral skills. Auditory memory, as a kind of memory, can be influenced by strengthening processes following long term chess playing like other behavioral skills because of common processing pathways in the brain. The purpose of this study was to evaluate the auditory memory function of expert chess players using the Persian version of dichotic auditory-verbal memory test. Methods: The Persian version of dichotic auditory-verbal memory test was performed for 30 expert chess players aged 20-35 years and 30 non chess players who were matched by different conditions; the participants in both groups were randomly selected. The performance of the two groups was compared by independent samples t-test using SPSS version 21. Results: The mean score of dichotic auditory-verbal memory test between the two groups, expert chess players and non-chess players, revealed a significant difference (p≤ 0.001). The difference between the ears scores for expert chess players (p= 0.023) and non-chess players (p= 0.013) was significant. Gender had no effect on the test results. Conclusion: Auditory memory function in expert chess players was significantly better compared to non-chess players. It seems that increased auditory memory function is related to strengthening cognitive performances due to playing chess for a long time. PMID:26793666

ERP evidence for hemispheric asymmetries in abstract but not exemplar-specific repetition priming.

PubMed

Küper, Kristina; Liesefeld, Anna M; Zimmer, Hubert D

2015-12-01

Implicit memory retrieval is thought to be exemplar-specific in the right hemisphere (RH) but abstract in the left hemisphere (LH). Yet, conflicting behavioral priming results illustrate that the level at which asymmetries take effect is difficult to pinpoint. In the present divided visual field experiment, we tried to address this issue by analyzing ERPs in addition to behavioral measures. Participants made a natural/artificial decision on lateralized visual objects that were either new, identical repetitions, or different exemplars of studied items. Hemispheric asymmetries did not emerge in either behavioral or late positive complex (LPC) priming effects, but did affect the process of implicit memory retrieval proper as indexed by an early frontal negativity (N350/(F)N400). Whereas exemplar-specific N350/(F)N400 priming effects emerged irrespective of presentation side, abstract implicit memory retrieval of different exemplars was contingent on right visual field presentation and the ensuing initial stimulus processing by the LH. © 2015 Society for Psychophysiological Research.

Developmental gains in visuospatial memory predict gains in mathematics achievement.

PubMed

Li, Yaoran; Geary, David C

2013-01-01

Visuospatial competencies are related to performance in mathematical domains in adulthood, but are not consistently related to mathematics achievement in children. We confirmed the latter for first graders and demonstrated that children who show above average first-to-fifth grade gains in visuospatial memory have an advantage over other children in mathematics. The study involved the assessment of the mathematics and reading achievement of 177 children in kindergarten to fifth grade, inclusive, and their working memory capacity and processing speed in first and fifth grade. Intelligence was assessed in first grade and their second to fourth grade teachers reported on their in-class attentive behavior. Developmental gains in visuospatial memory span (d = 2.4) were larger than gains in the capacity of the central executive (d = 1.6) that in turn were larger than gains in phonological memory span (d = 1.1). First to fifth grade gains in visuospatial memory and in speed of numeral processing predicted end of fifth grade mathematics achievement, as did first grade central executive scores, intelligence, and in-class attentive behavior. The results suggest there are important individual differences in the rate of growth of visuospatial memory during childhood and that these differences become increasingly important for mathematics learning.

Developmental Gains in Visuospatial Memory Predict Gains in Mathematics Achievement

PubMed Central

Li, Yaoran; Geary, David C.

2013-01-01

Visuospatial competencies are related to performance in mathematical domains in adulthood, but are not consistently related to mathematics achievement in children. We confirmed the latter for first graders and demonstrated that children who show above average first-to-fifth grade gains in visuospatial memory have an advantage over other children in mathematics. The study involved the assessment of the mathematics and reading achievement of 177 children in kindergarten to fifth grade, inclusive, and their working memory capacity and processing speed in first and fifth grade. Intelligence was assessed in first grade and their second to fourth grade teachers reported on their in-class attentive behavior. Developmental gains in visuospatial memory span (d = 2.4) were larger than gains in the capacity of the central executive (d = 1.6) that in turn were larger than gains in phonological memory span (d = 1.1). First to fifth grade gains in visuospatial memory and in speed of numeral processing predicted end of fifth grade mathematics achievement, as did first grade central executive scores, intelligence, and in-class attentive behavior. The results suggest there are important individual differences in the rate of growth of visuospatial memory during childhood and that these differences become increasingly important for mathematics learning. PMID:23936154

Working memory training promotes general cognitive abilities in genetically heterogeneous mice.

PubMed

Light, Kenneth R; Kolata, Stefan; Wass, Christopher; Denman-Brice, Alexander; Zagalsky, Ryan; Matzel, Louis D

2010-04-27

In both humans and mice, the efficacy of working memory capacity and its related process, selective attention, are each strongly predictive of individuals' aggregate performance in cognitive test batteries [1-9]. Because working memory is taxed during most cognitive tasks, the efficacy of working memory may have a causal influence on individuals' performance on tests of "intelligence" [10, 11]. Despite the attention this has received, supporting evidence has been largely correlational in nature (but see [12]). Here, genetically heterogeneous mice were assessed on a battery of five learning tasks. Animals' aggregate performance across the tasks was used to estimate their general cognitive abilities, a trait that is in some respects analogous to intelligence [13, 14]. Working memory training promoted an increase in animals' selective attention and their aggregate performance on these tasks. This enhancement of general cognitive performance by working memory training was attenuated if its selective attention demands were reduced. These results provide evidence that the efficacy of working memory capacity and selective attention may be causally related to an animal's general cognitive performance and provide a framework for behavioral strategies to promote those abilities. Furthermore, the pattern of behavior reported here reflects a conservation of the processes that regulate general cognitive performance in humans and infrahuman animals. Copyright © 2010 Elsevier Ltd. All rights reserved.

Behavioral and Neural Correlates of Executive Function: Interplay between Inhibition and Updating Processes.

PubMed

Kim, Na Young; Wittenberg, Ellen; Nam, Chang S

2017-01-01

This study investigated the interaction between two executive function processes, inhibition and updating, through analyses of behavioral, neurophysiological, and effective connectivity metrics. Although, many studies have focused on behavioral effects of executive function processes individually, few studies have examined the dynamic causal interactions between these two functions. A total of twenty participants from a local university performed a dual task combing flanker and n-back experimental paradigms, and completed the Operation Span Task designed to measure working memory capacity. We found that both behavioral (accuracy and reaction time) and neurophysiological (P300 amplitude and alpha band power) metrics on the inhibition task (i.e., flanker task) were influenced by the updating load (n-back level) and modulated by working memory capacity. Using independent component analysis, source localization (DIPFIT), and Granger Causality analysis of the EEG time-series data, the present study demonstrated that manipulation of cognitive demand in a dual executive function task influenced the causal neural network. We compared connectivity across three updating loads (n-back levels) and found that experimental manipulation of working memory load enhanced causal connectivity of a large-scale neurocognitive network. This network contains the prefrontal and parietal cortices, which are associated with inhibition and updating executive function processes. This study has potential applications in human performance modeling and assessment of mental workload, such as the design of training materials and interfaces for those performing complex multitasking under stress.

The Effect of Using a Written Preanesthetic Machine Checklist on Detection of Anesthesia Machine Faults.

DTIC Science & Technology

1986-08-01

Craik and Lockhart describes the various levels of information processing involved in memory (8). The preliminary level ...A prevalent malfunction. Anesthesia and Analg~esia, 1985, 64: 745-747. 8. Craik , F.I.M., Lockhart , R.S. Levels of processing : A framework for memory...research. Journal of Verbal Learning and Behavior, 1972, 11: 671-684. 9. Craik , F.I.M., Lockhart , R.S. Levels of processing : A * framework for

Cognitive processes involved in smooth pursuit eye movements: behavioral evidence, neural substrate and clinical correlation

PubMed Central

Fukushima, Kikuro; Fukushima, Junko; Warabi, Tateo; Barnes, Graham R.

2013-01-01

Smooth-pursuit eye movements allow primates to track moving objects. Efficient pursuit requires appropriate target selection and predictive compensation for inherent processing delays. Prediction depends on expectation of future object motion, storage of motion information and use of extra-retinal mechanisms in addition to visual feedback. We present behavioral evidence of how cognitive processes are involved in predictive pursuit in normal humans and then describe neuronal responses in monkeys and behavioral responses in patients using a new technique to test these cognitive controls. The new technique examines the neural substrate of working memory and movement preparation for predictive pursuit by using a memory-based task in macaque monkeys trained to pursue (go) or not pursue (no-go) according to a go/no-go cue, in a direction based on memory of a previously presented visual motion display. Single-unit task-related neuronal activity was examined in medial superior temporal cortex (MST), supplementary eye fields (SEF), caudal frontal eye fields (FEF), cerebellar dorsal vermis lobules VI–VII, caudal fastigial nuclei (cFN), and floccular region. Neuronal activity reflecting working memory of visual motion direction and go/no-go selection was found predominantly in SEF, cerebellar dorsal vermis and cFN, whereas movement preparation related signals were found predominantly in caudal FEF and the same cerebellar areas. Chemical inactivation produced effects consistent with differences in signals represented in each area. When applied to patients with Parkinson's disease (PD), the task revealed deficits in movement preparation but not working memory. In contrast, patients with frontal cortical or cerebellar dysfunction had high error rates, suggesting impaired working memory. We show how neuronal activity may be explained by models of retinal and extra-retinal interaction in target selection and predictive control and thus aid understanding of underlying pathophysiology. PMID:23515488

A functional magnetic resonance imaging investigation of short-term source and item memory for negative pictures.

PubMed

Mitchell, Karen J; Mather, Mara; Johnson, Marcia K; Raye, Carol L; Greene, Erich J

2006-10-02

We investigated the hypothesis that arousal recruits attention to item information, thereby disrupting working memory processes that help bind items to context. Using functional magnetic resonance imaging, we compared brain activity when participants remembered negative or neutral picture-location conjunctions (source memory) versus pictures only. Behaviorally, negative trials showed disruption of short-term source, but not picture, memory; long-term picture recognition memory was better for negative than for neutral pictures. Activity in areas involved in working memory and feature integration (precentral gyrus and its intersect with superior temporal gyrus) was attenuated on negative compared with neutral source trials relative to picture-only trials. Visual processing areas (middle occipital and lingual gyri) showed greater activity for negative than for neutral trials, especially on picture-only trials.

Exploring Expressive Vocabulary Variability in Two-Year-Olds: The Role of Working Memory.

PubMed

Newbury, Jayne; Klee, Thomas; Stokes, Stephanie F; Moran, Catherine

2015-12-01

This study explored whether measures of working memory ability contribute to the wide variation in 2-year-olds' expressive vocabulary skills. Seventy-nine children (aged 24-30 months) were assessed by using standardized tests of vocabulary and visual cognition, a processing speed measure, and behavioral measures of verbal working memory and phonological short-term memory. Strong correlations were observed between phonological short-term memory, verbal working memory, and expressive vocabulary. Speed of spoken word recognition showed a moderate significant correlation with expressive vocabulary. In a multivariate regression model for expressive vocabulary, the most powerful predictor was a measure of phonological short-term memory (accounting for 66% unique variance), followed by verbal working memory (6%), sex (2%), and age (1%). Processing speed did not add significant unique variance. These findings confirm previous research positing a strong role for phonological short-term memory in early expressive vocabulary acquisition. They also extend previous research in two ways. First, a unique association between verbal working memory and expressive vocabulary in 2-year-olds was observed. Second, processing speed was not a unique predictor of variance in expressive vocabulary when included alongside measures of working memory.

Overexpression of α3/α5/β4 nicotinic receptor subunits modifies impulsive-like behavior.

PubMed

Viñals, Xavier; Molas, Susanna; Gallego, Xavier; Fernández-Montes, Rubén D; Robledo, Patricia; Dierssen, Mara; Maldonado, Rafael

2012-05-01

Recent studies have revealed that sequence variants in genes encoding the α3/α5/β4 nicotinic acetylcholine receptor subunits are associated with nicotine dependence. In this study, we evaluated two specific aspects of executive functioning related to drug addiction (impulsivity and working memory) in transgenic mice over expressing α3/α5/β4 nicotinic receptor subunits. Impulsivity and working memory were evaluated in an operant delayed alternation task, where mice must inhibit responding between 2 and 8s in order to receive food reinforcement. Working memory was also evaluated in a spontaneous alternation task in an open field. Transgenic mice showed less impulsive-like behavior than wild-type controls, and this behavioral phenotype was related to the number of copies of the transgene. Thus, transgenic Line 22 (16-28 copies) showed a more pronounced phenotype than Line 30 (4-5 copies). Overexpression of these subunits in Line 22 reduced spontaneous alternation behavior suggesting deficits in working memory processing in this particular paradigm. These results reveal the involvement of α3/α5/β4 nicotinic receptor subunits in working memory and impulsivity, two behavioral traits directly related to the vulnerability to develop nicotine dependence. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Gustatory processing and taste memory in Drosophila

PubMed Central

Masek, Pavel; Keene, Alex C.

2018-01-01

Taste allows animals to discriminate the value and potential toxicity of food prior to ingestion. Many tastants elicit an innate attractive or avoidance response that is modifiable with nutritional state and prior experience. A powerful genetic tool kit, well-characterized gustatory system, and standardized behavioral assays make the fruit fly, Drosophila melanogaster, an excellent system for investigating taste processing and memory. Recent studies have used this system to identify the neural basis for acquired taste preference. These studies have revealed a role for dopamine-mediated plasticity of the mushroom bodies that modulate the threshold of response to appetitive tastants. The identification of neural circuitry regulating taste memory provides a system to study the genetic and physiological processes that govern plasticity within a defined memory circuit. PMID:27328844

Associative memory cells and their working principle in the brain

PubMed Central

Wang, Jin-Hui; Cui, Shan

2018-01-01

The acquisition, integration and storage of exogenous associated signals are termed as associative learning and memory. The consequences and processes of associative thinking and logical reasoning based on these stored exogenous signals can be memorized as endogenous signals, which are essential for decision making, intention, and planning. Associative memory cells recruited in these primary and secondary associative memories are presumably the foundation for the brain to fulfill cognition events and emotional reactions in life, though the plasticity of synaptic connectivity and neuronal activity has been believed to be involved in learning and memory. Current reports indicate that associative memory cells are recruited by their mutual synapse innervations among co-activated brain regions to fulfill the integration, storage and retrieval of associated signals. The activation of these associative memory cells initiates information recall in the mind, and the successful activation of their downstream neurons endorses memory presentations through behaviors and emotion reactions. In this review, we aim to draw a comprehensive diagram for associative memory cells, working principle and modulation, as well as propose their roles in cognition, emotion and behaviors. PMID:29487741

The Role of Working Memory in the Probabilistic Inference of Future Sensory Events.

PubMed

Cashdollar, Nathan; Ruhnau, Philipp; Weisz, Nathan; Hasson, Uri

2017-05-01

The ability to represent the emerging regularity of sensory information from the external environment has been thought to allow one to probabilistically infer future sensory occurrences and thus optimize behavior. However, the underlying neural implementation of this process is still not comprehensively understood. Through a convergence of behavioral and neurophysiological evidence, we establish that the probabilistic inference of future events is critically linked to people's ability to maintain the recent past in working memory. Magnetoencephalography recordings demonstrated that when visual stimuli occurring over an extended time series had a greater statistical regularity, individuals with higher working-memory capacity (WMC) displayed enhanced slow-wave neural oscillations in the θ frequency band (4-8 Hz.) prior to, but not during stimulus appearance. This prestimulus neural activity was specifically linked to contexts where information could be anticipated and influenced the preferential sensory processing for this visual information after its appearance. A separate behavioral study demonstrated that this process intrinsically emerges during continuous perception and underpins a realistic advantage for efficient behavioral responses. In this way, WMC optimizes the anticipation of higher level semantic concepts expected to occur in the near future. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Effects of beta-adrenergic antagonist, propranolol on spatial memory and exploratory behavior in mice.

PubMed

Sun, Huaying; Mao, Yu; Wang, Jianhong; Ma, Yuanye

2011-07-08

The beta-adrenergic system has been suggested to be involved in novelty detection and memory modulation. The present study aimed to investigate the role of beta-adrenergic receptors on novelty-based spatial recognition memory and exploratory behavior in mice using Y-maze test and open-field respectively. Mice were injected with three doses of beta-adrenergic receptor antagonist, propranolol (2, 10 and 20 mg/kg) or saline at three different time points (15 min prior to training, immediately after training and 15 min before test). The results showed that higher doses of propranolol (10 and 20 mg/kg) given before the training trial impaired spatial recognition memory while those injected at other two time points did not. A detailed analysis of exploratory behavior in open-field showed that lower dose (2 mg/kg) of propranolol reduced exploratory behavior of mice. Our findings indicate that higher dose of propranolol can impair acquisition of spatial information in the Y-maze without altering locomotion, suggesting that the beta-adrenergic system may be involved in modulating memory processes at the time of learning. Copyright © 2011. Published by Elsevier Ireland Ltd.

A Dynamical Systems Explanation of the Hurst Effect and Atmospheric Low-Frequency Variability

PubMed Central

Franzke, Christian L. E.; Osprey, Scott M.; Davini, Paolo; Watkins, Nicholas W.

2015-01-01

The Hurst effect plays an important role in many areas such as physics, climate and finance. It describes the anomalous growth of range and constrains the behavior and predictability of these systems. The Hurst effect is frequently taken to be synonymous with Long-Range Dependence (LRD) and is typically assumed to be produced by a stationary stochastic process which has infinite memory. However, infinite memory appears to be at odds with the Markovian nature of most physical laws while the stationarity assumption lacks robustness. Here we use Lorenz's paradigmatic chaotic model to show that regime behavior can also cause the Hurst effect. By giving an alternative, parsimonious, explanation using nonstationary Markovian dynamics, our results question the common belief that the Hurst effect necessarily implies a stationary infinite memory process. We also demonstrate that our results can explain atmospheric variability without the infinite memory previously thought necessary and are consistent with climate model simulations. PMID:25765880

Control of interference during working memory updating.

PubMed

Szmalec, Arnaud; Verbruggen, Frederick; Vandierendonck, André; Kemps, Eva

2011-02-01

The current study examined the nature of the processes underlying working memory updating. In 4 experiments using the n-back paradigm, the authors demonstrate that continuous updating of items in working memory prevents strong binding of those items to their contexts in working memory, and hence leads to an increased susceptibility to proactive interference. Results of Experiments 1 and 2 show that this interference reflects a competition between a process that reveals the degree of familiarity of an item and a context-sensitive recollection process that depends on the strength of bindings in working memory. Experiment 3 further clarifies the origins of interference during updating by demonstrating that even items that are semantically related to the updated working memory contents but that have not been maintained in working memory before cause proactive interference. Finally, the results of Experiment 4 indicate that the occurrence of interference leads to top-down behavioral adjustments that prioritize recollection over familiarity assessment. The implications of these findings for the construct validity of the n-back task, for the control processes involved in working memory updating, and for the concept of executive control more generally are discussed. (c) 2010 APA, all rights reserved.

Salience of working-memory maintenance and manipulation deficits in schizophrenia

PubMed Central

Hill, S. K.; Griffin, G. B.; Miura, T. Kazuto; Herbener, E. S.; Sweeney, J. A.

2011-01-01

Background Encoding and maintenance of information in working memory, followed by internal manipulation of that information for planning adaptive behavior, are two key components of working-memory systems. Both processes have been reported to be impaired in schizophrenia, but few studies have directly compared the relative severity of these abnormalities, or the degree to which manipulation deficits might be secondary to alterations in maintenance processes. Method Clinically stable schizophrenia patients (n=25) and a demographically similar healthy comparison group (n=24) were administered a verbal span task with three levels of working-memory load. Maintenance was assessed using sequential position questions. Manipulation processes were assessed by requiring comparison of the relative sequential position of test items, which entailed simultaneous serial search strategies regarding item order. Results Both groups showed reduced accuracy and increased reaction time for manipulation compared with maintenance processing. There were significant patient impairments across working-memory loads. There was no differential deficit in manipulation processing, and effect sizes of relative deficit in the patient group were higher for maintenance than manipulation processing. Conclusions The strong correlation for maintenance and manipulation deficits suggest that impairments in the ability to internally manipulate information stored in working-memory systems are not greater than alterations in the encoding and maintaining of information in working memory and that disturbances in maintenance processing may contribute to deficits in higher-order working-memory operations. PMID:20214839

Epigenetic mechanisms of memory formation and reconsolidation.

PubMed

Jarome, Timothy J; Lubin, Farah D

2014-11-01

Memory consolidation involves transcriptional control of genes in neurons to stabilize a newly formed memory. Following retrieval, a once consolidated memory destabilizes and again requires gene transcription changes in order to restabilize, a process referred to as reconsolidation. Understanding the molecular mechanisms of gene transcription during the consolidation and reconsolidation processes could provide crucial insights into normal memory formation and memory dysfunction associated with psychiatric disorders. In the past decade, modifications of epigenetic markers such as DNA methylation and posttranslational modifications of histone proteins have emerged as critical transcriptional regulators of gene expression during initial memory formation and after retrieval. In light of the rapidly growing literature in this exciting area of research, we here examine the most recent and latest evidence demonstrating how memory acquisition and retrieval trigger epigenetic changes during the consolidation and reconsolidation phases to impact behavior. In particular we focus on the reconsolidation process, where we discuss the already identified epigenetic regulators of gene transcription during memory reconsolidation, while exploring other potential epigenetic modifications that may also be involved, and expand on how these epigenetic modifications may be precisely and temporally controlled by important signaling cascades critical to the reconsolidation process. Finally, we explore the possibility that epigenetic mechanisms may serve to regulate a system or circuit level reconsolidation process and may be involved in retrieval-dependent memory updating. Hence, we propose that epigenetic mechanisms coordinate changes in neuronal gene transcription, not only during the initial memory consolidation phase, but are triggered by retrieval to regulate molecular and cellular processes during memory reconsolidation. Copyright © 2014 Elsevier Inc. All rights reserved.

Epigenetic Mechanisms of Memory Formation and Reconsolidation

PubMed Central

Jarome, Timothy J.; Lubin, Farah D.

2014-01-01

Memory consolidation involves transcriptional control of genes in neurons to stabilize a newly formed memory. Following retrieval, a once consolidated memory destabilizes and again requires gene transcription changes in order to restabilize, a process referred to as reconsolidation. Understanding the molecular mechanisms of gene transcription during the consolidation and reconsolidation processes could provide crucial insights into normal memory formation and memory dysfunction associated with psychiatric disorders. In the past decade, modifications of epigenetic markers such as DNA methylation and posttranslational modifications of histone proteins have emerged as critical transcriptional regulators of gene expression during initial memory formation and after retrieval. In light of the rapidly growing literature in this exciting area of research, we here examine the most recent and latest evidence demonstrating how memory acquisition and retrieval trigger epigenetic changes during the consolidation and reconsolidation phases to impact behavior. In particular we focus on the reconsolidation process, where we discuss the already identified epigenetic regulators of gene transcription during memory reconsolidation, while exploring other potential epigenetic modifications that may also be involved, and expand on how these epigenetic modifications may be precisely and temporally controlled by important signaling cascades critical to the reconsolidation process. Finally, we explore the possibility that epigenetic mechanisms may serve to regulate a system or circuit level reconsolidation process and may be involved in retrieval-dependent memory updating. Hence, we propose that epigenetic mechanisms coordinate changes in neuronal gene transcription, not only during the initial memory consolidation phase, but are triggered by retrieval to regulate molecular and cellular processes during memory reconsolidation. PMID:25130533

Predictive Coding Strategies for Invariant Object Recognition and Volitional Motion Control in Neuromorphic Agents

DTIC Science & Technology

2015-09-02

human behavior. In this project, we hypothesized that visual memory of past motion trajectories may be used for selecting future behavior. In other...34Decoding sequence of actions using fMRI ", Society for Neuroscience Annual Meeting, San Diego, CA, USA, Nov 9-13 2013 (only abstract) 3. Hansol Choi, Dae...Shik Kim, "Planning as inference in a Hierarchical Predictive Memory ", Proceedings of International Conference on Neural Information Processing

Rethinking Extinction

PubMed Central

Dunsmoor, Joseph E.; Niv, Yael; Daw, Nathaniel; Phelps, Elizabeth A.

2015-01-01

Extinction serves as the leading theoretical framework and experimental model to describe how learned behaviors diminish through absence of anticipated reinforcement. In the past decade, extinction has moved beyond the realm of associative learning theory and behavioral experimentation in animals and has become a topic of considerable interest in the neuroscience of learning, memory, and emotion. Here, we review research and theories of extinction, both as a learning process and as a behavioral technique, and consider whether traditional understandings warrant a re-examination. We discuss the neurobiology, cognitive factors, and major computational theories, and revisit the predominant view that extinction results in new learning that interferes with expression of the original memory. Additionally, we reconsider the limitations of extinction as a technique to prevent the relapse of maladaptive behavior, and discuss novel approaches, informed by contemporary theoretical advances, that augment traditional extinction methods to target and potentially alter maladaptive memories. PMID:26447572

Prior parity positively regulates learning and memory in young and middle-aged rats.

PubMed

Zimberknopf, Erica; Xavier, Gilberto F; Kinsley, Craig H; Felicio, Luciano F

2011-08-01

Reproductive experience in female rats modifies acquired behaviors, induces long-lasting functional neuroadaptations and can also modify spatial learning and memory. The present study supports and expands this knowledge base by employing the Morris water maze, which measures spatial memory. Age-matched young adult (YNG) nulliparous (NULL; nonmated) and primiparous (PRIM; one pregnancy and lactation) female rats were tested 15 d after the litter's weaning. In addition, corresponding middle-aged (AGD) PRIM (mated in young adulthood so that pregnancy, parturition, and lactation occurred at the same age as in YNG PRIM) and NULL female rats were tested at 18 mo of age. Behavioral evaluation included: 1) acquisition of reference memory (platform location was fixed for 14 to 19 d of testing); 2) retrieval of this information associated with extinction of the acquired response (probe test involving removal of the platform 24 h after the last training session); and 3) performance in a working memory version of the task (platform presented in a novel location every day for 13 d, and maintained in a fixed location within each day). YNG PRIM outperformed NULL rats and showed different behavioral strategies. These results may be related to changes in locomotor, mnemonic, and cognitive processes. In addition, YNG PRIM exhibited less anxiety-like behavior. Compared with YNG rats, AGD rats showed less behavioral flexibility but stronger memory consolidation. These data, which were obtained by using a well-documented spatial task, demonstrate long lasting modifications of behavioral strategies in both YNG and AGD rats associated with a single reproductive experience.

Functional neuroimaging and behavioral correlates of capacity decline in visual short-term memory after sleep deprivation.

PubMed

Chee, Michael W L; Chuah, Y M Lisa

2007-05-29

Sleep deprivation (SD) impairs short-term memory, but it is unclear whether this is because of reduced storage capacity or processes contributing to appropriate information encoding. We evaluated 30 individuals twice, once after a night of normal sleep and again after 24 h of SD. In each session, we evaluated visual memory capacity by presenting arrays of one to eight colored squares. Additionally, we measured cortical responses to varying visual array sizes without engaging memory. The magnitude of intraparietal sulcus activation and memory capacity after normal sleep were highly correlated. SD elicited a pattern of activation in both tasks, indicating that deficits in visual processing and visual attention accompany and could account for loss of short-term memory capacity. Additionally, a comparison between better and poorer performers showed that preservation of precuneus and temporoparietal junction deactivation with increasing memory load corresponds to less performance decline when one is sleep-deprived.

Maternal Scaffolding and Preterm Toddlers’ Visual-Spatial Processing and Emerging Working Memory

PubMed Central

Poehlmann, Julie; Hilgendorf, Amy E; Miller, Kyle; Lambert, Heather

2010-01-01

Objective We examined longitudinal associations among neonatal and socioeconomic risks, maternal scaffolding behaviors, and 24-month visual-spatial processing and working memory in a sample of 73 toddlers born preterm or low birthweight (PT LBW). Methods Risk data were collected at hospital discharge and dyadic play interactions were observed at 16-months postterm. Abbreviated IQ scores, verbal/nonverbal working memory, and verbal/nonverbal visual-spatial processing data were collected at 24-months postterm. Results Higher attention scaffolding and lower emotion scaffolding during 16-month play were associated with 24-month verbal working memory scores. A joint significance test revealed that maternal attention and emotion scaffolding during 16-month play mediated the relationship between socioeconomic risk and 24-month verbal working memory. Conclusions These findings suggest areas for future research and intervention with children born PT LBW who also experience high socioeconomic risk. PMID:19505998

Aerobic Exercise During Encoding Impairs Hippocampus-Dependent Memory.

PubMed

Soga, Keishi; Kamijo, Keita; Masaki, Hiroaki

2017-08-01

We investigated how aerobic exercise during encoding affects hippocampus-dependent memory through a source memory task that assessed hippocampus-independent familiarity and hippocampus-dependent recollection processes. Using a within-participants design, young adult participants performed a memory-encoding task while performing a cycling exercise or being seated. The subsequent retrieval phase was conducted while sitting on a chair. We assessed behavioral and event-related brain potential measures of familiarity and recollection processes during the retrieval phase. Results indicated that source accuracy was lower for encoding with exercise than for encoding in the resting condition. Event-related brain potential measures indicated that the parietal old/new effect, which has been linked to recollection processing, was observed in the exercise condition, whereas it was absent in the rest condition, which is indicative of exercise-induced hippocampal activation. These findings suggest that aerobic exercise during encoding impairs hippocampus-dependent memory, which may be attributed to inefficient source encoding during aerobic exercise.

Objectives and Strategies in the Layperson's Categorization of Behavior.

ERIC Educational Resources Information Center

Hoffman, Curt; Mischel, Walter

The effects of observational purpose are thought to impact on such diverse processes as categorization, behavior perception, trait ascription, and memory. The role of observational purpose in the categorization of behavior was explored to determine whether differences between trait and goal concepts affect certain information-processing…

Astrocytes contribute to gamma oscillations and recognition memory.

PubMed

Lee, Hosuk Sean; Ghetti, Andrea; Pinto-Duarte, António; Wang, Xin; Dziewczapolski, Gustavo; Galimi, Francesco; Huitron-Resendiz, Salvador; Piña-Crespo, Juan C; Roberts, Amanda J; Verma, Inder M; Sejnowski, Terrence J; Heinemann, Stephen F

2014-08-12

Glial cells are an integral part of functional communication in the brain. Here we show that astrocytes contribute to the fast dynamics of neural circuits that underlie normal cognitive behaviors. In particular, we found that the selective expression of tetanus neurotoxin (TeNT) in astrocytes significantly reduced the duration of carbachol-induced gamma oscillations in hippocampal slices. These data prompted us to develop a novel transgenic mouse model, specifically with inducible tetanus toxin expression in astrocytes. In this in vivo model, we found evidence of a marked decrease in electroencephalographic (EEG) power in the gamma frequency range in awake-behaving mice, whereas neuronal synaptic activity remained intact. The reduction in cortical gamma oscillations was accompanied by impaired behavioral performance in the novel object recognition test, whereas other forms of memory, including working memory and fear conditioning, remained unchanged. These results support a key role for gamma oscillations in recognition memory. Both EEG alterations and behavioral deficits in novel object recognition were reversed by suppression of tetanus toxin expression. These data reveal an unexpected role for astrocytes as essential contributors to information processing and cognitive behavior.

Effects of sublethal doses of thiacloprid and its formulation Calypso® on the learning and memory performance of honey bees.

PubMed

Tison, Léa; Holtz, Sophie; Adeoye, Amy; Kalkan, Önder; Irmisch, Nina S; Lehmann, Nadja; Menzel, Randolf

2017-10-15

Learning and memory play a central role in the behavior and communication of foraging bees. We have previously shown that chronic uptake of the neonicotinoid thiacloprid affects the behavior of honey bees in the field. Foraging behavior, homing success, navigation performance and social communication were impaired. Thiacloprid collected at a feeding site at low doses accumulates in foragers over time. Here, we applied a laboratory standard procedure (the proboscis-extension response conditioning) in order to assess which processes, acquisition, memory consolidation and/or memory retrieval were compromised after bees were fed either with thiacloprid or the formulation of thiacloprid named Calypso ® at different sublethal doses. Extinction and generalization tests allowed us to investigate whether bees respond to a learned stimulus, and how selectively. We showed that thiacloprid, as active substance and as formulation, poses a substantial risk to honey bees by disrupting learning and memory functions. These data support and specify the data collected in the field. © 2017. Published by The Company of Biologists Ltd.

Persistent neural activity in auditory cortex is related to auditory working memory in humans and nonhuman primates

PubMed Central

Huang, Ying; Matysiak, Artur; Heil, Peter; König, Reinhard; Brosch, Michael

2016-01-01

Working memory is the cognitive capacity of short-term storage of information for goal-directed behaviors. Where and how this capacity is implemented in the brain are unresolved questions. We show that auditory cortex stores information by persistent changes of neural activity. We separated activity related to working memory from activity related to other mental processes by having humans and monkeys perform different tasks with varying working memory demands on the same sound sequences. Working memory was reflected in the spiking activity of individual neurons in auditory cortex and in the activity of neuronal populations, that is, in local field potentials and magnetic fields. Our results provide direct support for the idea that temporary storage of information recruits the same brain areas that also process the information. Because similar activity was observed in the two species, the cellular bases of some auditory working memory processes in humans can be studied in monkeys. DOI: http://dx.doi.org/10.7554/eLife.15441.001 PMID:27438411

Emotional and Cognitive Information Processing: Relations to Behavioral Performance and Hippocampal Long-Term Potentiation In Vivo during a Spatial Water Maze Training in Rats

ERIC Educational Resources Information Center

Schulz, Kristina; Korz, Volker

2010-01-01

Emotionality as well as cognitive abilities contribute to the acquisition and retrieval of memories as well as to the consolidation of long-term potentiation (LTP), a cellular model of memory formation. However, little is known about the timescale and relative contribution of these processes. Therefore, we tested the effects of weak water maze…

Cognitive Strategies and Skill Acquisition.

DTIC Science & Technology

1981-02-09

Behavior (Acadmic Press, N.Y., 1974). ( 9). Craik , F.I.M., 8 Lockhart , R.S., Levels of processing : A frame- work for memory research, Journal of...C.D., a Stein, B.S., Some general constraints on learning and memory research, in: F.I.M. Craik 6 L.S. Cermak.(eds.), Levels of Processing and...instructions, or instructions in the use of particular strategies. (Belmont & Butterfield, 1971; Craik & Lockhart , 1972; Weinstein, 1978) have had

Functional Brain Network Abnormalities during Verbal Working Memory Performance in Adolescents and Young Adults with Dyslexia

ERIC Educational Resources Information Center

Wolf, Robert Christian; Sambataro, Fabio; Lohr, Christina; Steinbrink, Claudia; Martin, Claudia; Vasic, Nenad

2010-01-01

Behavioral and functional neuroimaging studies indicate deficits in verbal working memory (WM) and frontoparietal dysfunction in individuals with dyslexia. Additionally, structural brain abnormalities in dyslexics suggest a dysconnectivity of brain regions associated with phonological processing. However, little is known about the functional…

The role of cue detection for prospective memory development across the lifespan.

PubMed

Hering, Alexandra; Wild-Wall, Nele; Gajewski, Patrick D; Falkenstein, Michael; Kliegel, Matthias; Zinke, Katharina

2016-12-01

Behavioral findings suggest an inverted U-shaped pattern of prospective memory development across the lifespan. A key mechanism underlying this development is the ability to detect cues. We examined the influence of cue detection on prospective memory, combining behavioral and electrophysiological measures, in three age groups: adolescents (12-14 years), young (19-28 years), and old adults (66-77 years). Cue detection was manipulated by varying the distinctiveness (i.e., how easy it was to detect the cue based on color) of the prospective memory cue in a semantic judgment ongoing task. Behavioral results supported the pattern of an inverted U-shape with a pronounced prospective memory decrease in old adults. Adolescents and young adults showed a prospective memory specific modulation (larger amplitudes for the cues compared to other trials) already for the N1 component. No such specific modulation was evident in old adults for the early N1 component but only at the later P3b component. Adolescents showed differential modulations of the amplitude also for irrelevant information at the P3b, suggesting less efficient processing. In terms of conceptual implications, present findings underline the importance of cue detection for prospective remembering and reveal different developmental trajectories for cue detection. Our findings suggest that cue detection is not a unitary process but consists of multiple stages corresponding to several ERP components that differentially contribute to prospective memory performance across the lifespan. In adolescents resource allocation for detecting cues seemed successful initially but less efficient at later stages; whereas we found the opposite pattern for old adults. Copyright © 2016 Elsevier Ltd. All rights reserved.

I. WORKING MEMORY CAPACITY IN CONTEXT: MODELING DYNAMIC PROCESSES OF BEHAVIOR, MEMORY, AND DEVELOPMENT.

PubMed

Simmering, Vanessa R

2016-09-01

Working memory is a vital cognitive skill that underlies a broad range of behaviors. Higher cognitive functions are reliably predicted by working memory measures from two domains: children's performance on complex span tasks, and infants' performance in looking paradigms. Despite the similar predictive power across these research areas, theories of working memory development have not connected these different task types and developmental periods. The current project takes a first step toward bridging this gap by presenting a process-oriented theory, focusing on two tasks designed to assess visual working memory capacity in infants (the change-preference task) versus children and adults (the change detection task). Previous studies have shown inconsistent results, with capacity estimates increasing from one to four items during infancy, but only two to three items during early childhood. A probable source of this discrepancy is the different task structures used with each age group, but prior theories were not sufficiently specific to explain how performance relates across tasks. The current theory focuses on cognitive dynamics, that is, how memory representations are formed, maintained, and used within specific task contexts over development. This theory was formalized in a computational model to generate three predictions: 1) capacity estimates in the change-preference task should continue to increase beyond infancy; 2) capacity estimates should be higher in the change-preference versus change detection task when tested within individuals; and 3) performance should correlate across tasks because both rely on the same underlying memory system. I also tested a fourth prediction, that development across tasks could be explained through increasing real-time stability, realized computationally as strengthening connectivity within the model. Results confirmed these predictions, supporting the cognitive dynamics account of performance and developmental changes in real-time stability. The monograph concludes with implications for understanding memory, behavior, and development in a broader range of cognitive development. © 2016 The Society for Research in Child Development, Inc.

Sequenced neurocognitive and behavioral parent training for the treatment of ADHD in school-age children.

PubMed

Chacko, A; Bedard, A-C V; Marks, D; Gopalan, G; Feirsen, N; Uderman, J; Chimiklis, A; Heber, E; Cornwell, M; Anderson, L; Zwilling, A; Ramon, M

2018-05-01

The present study examines the potential of sequencing a neurocognitive intervention with behavioral parent training (BPT) to improve executive functions (EFs), psychiatric symptoms, and multiple indices of functional impairment in school-age children aged 7 to 11 years who have been diagnosed with attention-deficit/hyperactivity disorder (ADHD). Specifically, in a randomized controlled trial design, 85 children were assigned to either Cogmed Working Memory Training (CWMT) followed by an empirically supported, manualized BPT intervention, or to a placebo version of CWMT followed by the same BPT intervention. Working memory maintenance (i.e., attention control/short-term memory), working memory processing and manipulation, ADHD and oppositional defiant disorder (ODD) symptoms, impairment in parent-child dynamics, familial impairment, and overall functional compromise were evaluated as outcomes. The results suggest specific effects of the combined CWMT and BPT program on verbal and nonverbal working memory storage and nonverbal working memory processing and manipulation but no incremental benefits in regard to ADHD symptoms, ODD symptoms, and functional outcomes. The present findings do not support the hypothesis regarding the complementary and augmentative benefits of sequenced neurocognitive and BPT interventions for the treatment of ADHD. These results, the study's limitations, and future directions for research are further discussed.

Quantifying Age-Related Differences in Information Processing Behaviors When Viewing Prescription Drug Labels

PubMed Central

Sundar, Raghav Prashant; Becker, Mark W.; Bello, Nora M.; Bix, Laura

2012-01-01

Adverse drug events (ADEs) are a significant problem in health care. While effective warnings have the potential to reduce the prevalence of ADEs, little is known about how patients access and use prescription labeling. We investigated the effectiveness of prescription warning labels (PWLs, small, colorful stickers applied at the pharmacy) in conveying warning information to two groups of patients (young adults and those 50+). We evaluated the early stages of information processing by tracking eye movements while participants interacted with prescription vials that had PWLs affixed to them. We later tested participants’ recognition memory for the PWLs. During viewing, participants often failed to attend to the PWLs; this effect was more pronounced for older than younger participants. Older participants also performed worse on the subsequent memory test. However, when memory performance was conditionalized on whether or not the participant had fixated the PWL, these age-related differences in memory were no longer significant, suggesting that the difference in memory performance between groups was attributable to differences in attention rather than differences in memory encoding or recall. This is important because older adults are recognized to be at greater risk for ADEs. These data provide a compelling case that understanding consumers’ attentive behavior is crucial to developing an effective labeling standard for prescription drugs. PMID:22719955

Determinants to trigger memory reconsolidation: The role of retrieval and updating information.

PubMed

Rodriguez-Ortiz, Carlos J; Bermúdez-Rattoni, Federico

2017-07-01

Long-term memories can undergo destabilization/restabilization processes, collectively called reconsolidation. However, the parameters that trigger memory reconsolidation are poorly understood and are a matter of intense investigation. Particularly, memory retrieval is widely held as requisite to initiate reconsolidation. This assumption makes sense since only relevant cues will induce reconsolidation of a specific memory. However, recent studies show that pharmacological inhibition of retrieval does not avoid memory from undergoing reconsolidation, indicating that memory reconsolidation occurs through a process that can be dissociated from retrieval. We propose that retrieval is not a unitary process but has two dissociable components; one leading to the expression of memory and the other to reconsolidation, referred herein as executer and integrator respectively. The executer would lead to the behavioral expression of the memory. This component would be the one disrupted on the studies that show reconsolidation independence from retrieval. The integrator would deal with reconsolidation. This component of retrieval would lead to long-term memory destabilization when specific conditions are met. We think that an important number of reports are consistent with the hypothesis that reconsolidation is only initiated when updating information is acquired. We suggest that the integrator would initiate reconsolidation to integrate updating information into long-term memory. Copyright © 2016 Elsevier Inc. All rights reserved.

Relationships between behavioral syndromes and cognitive domains in Alzheimer disease: the impact of mood and psychosis.

PubMed

Koppel, Jeremy; Goldberg, Terry E; Gordon, Marc L; Huey, Edward; Davies, Peter; Keehlisen, Linda; Huet, Sara; Christen, Erica; Greenwald, Blaine S

2012-11-01

Behavioral disturbances occur in nearly all Alzheimer disease (AD) patients together with an array of cognitive impairments. Prior investigations have failed to demonstrate specific associations between them, suggesting an independent, rather than shared, pathophysiology. The objective of this study was to reexamine this issue using an extensive cognitive battery together with a sensitive neurobehavioral and functional rating scale to correlate behavioral syndromes and cognitive domains across the spectrum of impairment in dementia. Cross-sectional study of comprehensive cognitive and behavioral ratings in subjects with AD and mild cognitive impairment. Memory disorders research center. Fifty subjects with AD and 26 subjects with mild cognitive impairment; and their caregivers. Cognitive rating scales administered included the Mini-Mental State Examination; the Modified Mini-Mental State Examination; the Boston Naming Test; the Benton Visual Retention Test; the Consortium to Establish a Registry for Alzheimer's Disease Neuropsychology Assessment; the Controlled Oral Word Test; the Wechsler Memory Scale logical memory I and logical memory II task; the Wechsler Memory Scale-Revised digit span; the Wechsler Adult Intelligence Scale-Revised digit symbol task; and the Clock Drawing Task together with the Clinical Dementia Rating Scale and the Neuropsychiatric Inventory. Stepwise regression of cognitive domains with symptom domains revealed significant associations of mood with impaired executive function/speed of processing (Δr = 0.22); impaired working memory (Δr = 0.05); impaired visual memory (Δr = 0.07); and worsened Clinical Dementia Rating Scale (Δr = 0.08). Psychosis was significantly associated with impaired working memory (Δr = 0.13). Mood symptoms appear to impact diverse cognitive realms and to compromise functional performance. Among neuropsychological indices, the unique relationship between working memory and psychosis suggests a possible common underlying neurobiology. 2012 American Association for Geriatric Psychiatry

Dissociating interference-control processes between memory and response.

PubMed

Bissett, Patrick G; Nee, Derek Evan; Jonides, John

2009-09-01

The ability to mitigate interference is of central importance to cognition. Previous research has provided conflicting accounts about whether operations that resolve interference are singular in character or form a family of functions. Here, the authors examined the relationship between interference-resolution processes acting on working memory representations versus responses. The authors combined multiple forms of interference into a single paradigm by merging a directed-forgetting task, which induces proactive interference, with a stop-signal task, which taps response inhibition processes. The results demonstrated that proactive interference and response inhibition produced distinct behavioral signatures that did not interact. By contrast, combining two different measures of response inhibition by merging a go/no-go task variant and a stop signal produced overadditive behavioral interference, demonstrating that different forms of response inhibition tap the same processes. However, not all forms of response conflict interacted, suggesting that inhibition-related functions acting on response selection are dissociable from those acting on response inhibition. These results suggest that inhibition-related functions for memory and responses are dissociable. (c) 2009 APA, all rights reserved.

The hippocampo-amygdala control of contextual fear expression is affected in a model of intellectual disability.

PubMed

Zhang, Chun-Lei; Houbaert, Xander; Lepleux, Marilyn; Deshors, Melissa; Normand, Elisabeth; Gambino, Frédéric; Herzog, Etienne; Humeau, Yann

2015-11-01

The process of learning mainly depends on the ability to store new information, while the ability to retrieve this information and express appropriate behaviors are also crucial for the adaptation of individuals to environmental cues. Thereby, all three components contribute to the cognitive fitness of an individual. While a lack of behavioral adaptation is a recurrent trait of intellectually disabled patients, discriminating between memory formation, memory retrieval or behavioral expression deficits is not easy to establish. Here, we report some deficits in contextual fear behavior in knockout mice for the intellectual disability gene Il1rapl1. Functional in vivo experiments revealed that the lack of conditioned response resulted from a local inhibitory to excitatory (I/E) imbalance in basolateral amygdala (BLA) consecutive to a loss of excitatory drive onto BLA principal cells by caudal hippocampus axonal projections. A normalization of the fear behavior was obtained in adult mutant mice following opsin-based in vivo synaptic priming of hippocampo-BLA synapses in adult il1rapl1 knockout mice, indicating that synaptic efficacy at hippocampo-BLA projections is crucial for contextual fear memory expression. Importantly, because this restoration was obtained after the learning phase, our results suggest that some of the genetically encoded cognitive deficits in humans may originate from a lack of restitution of genuinely formed memories rather than an exclusive inability to store new memories.

Enhanced stability of car-following model upon incorporation of short-term driving memory

NASA Astrophysics Data System (ADS)

Liu, Da-Wei; Shi, Zhong-Ke; Ai, Wen-Huan

2017-06-01

Based on the full velocity difference model, a new car-following model is developed to investigate the effect of short-term driving memory on traffic flow in this paper. Short-term driving memory is introduced as the influence factor of driver's anticipation behavior. The stability condition of the newly developed model is derived and the modified Korteweg-de Vries (mKdV) equation is constructed to describe the traffic behavior near the critical point. Via numerical method, evolution of a small perturbation is investigated firstly. The results show that the improvement of this new car-following model over the previous ones lies in the fact that the new model can improve the traffic stability. Starting and breaking processes of vehicles in the signalized intersection are also investigated. The numerical simulations illustrate that the new model can successfully describe the driver's anticipation behavior, and that the efficiency and safety of the vehicles passing through the signalized intersection are improved by considering short-term driving memory.

Sleep and dreaming are for important matters

PubMed Central

Perogamvros, L.; Dang-Vu, T. T.; Desseilles, M.; Schwartz, S.

2013-01-01

Recent studies in sleep and dreaming have described an activation of emotional and reward systems, as well as the processing of internal information during these states. Specifically, increased activity in the amygdala and across mesolimbic dopaminergic regions during REM sleep is likely to promote the consolidation of memory traces with high emotional/motivational value. Moreover, coordinated hippocampal-striatal replay during NREM sleep may contribute to the selective strengthening of memories for important events. In this review, we suggest that, via the activation of emotional/motivational circuits, sleep and dreaming may offer a neurobehavioral substrate for the offline reprocessing of emotions, associative learning, and exploratory behaviors, resulting in improved memory organization, waking emotion regulation, social skills, and creativity. Dysregulation of such motivational/emotional processes due to sleep disturbances (e.g., insomnia, sleep deprivation) would predispose to reward-related disorders, such as mood disorders, increased risk-taking and compulsive behaviors, and may have major health implications, especially in vulnerable populations. PMID:23898315

Modeling of long-range memory processes with inverse cubic distributions by the nonlinear stochastic differential equations

NASA Astrophysics Data System (ADS)

Kaulakys, B.; Alaburda, M.; Ruseckas, J.

2016-05-01

A well-known fact in the financial markets is the so-called ‘inverse cubic law’ of the cumulative distributions of the long-range memory fluctuations of market indicators such as a number of events of trades, trading volume and the logarithmic price change. We propose the nonlinear stochastic differential equation (SDE) giving both the power-law behavior of the power spectral density and the long-range dependent inverse cubic law of the cumulative distribution. This is achieved using the suggestion that when the market evolves from calm to violent behavior there is a decrease of the delay time of multiplicative feedback of the system in comparison to the driving noise correlation time. This results in a transition from the Itô to the Stratonovich sense of the SDE and yields a long-range memory process.

Embodied simulation in exposure-based therapies for posttraumatic stress disorder—a possible integration of cognitive behavioral theories, neuroscience, and psychoanalysis

PubMed Central

Peri, Tuvia; Gofman, Mordechai; Tal, Shahar; Tuval-Mashiach, Rivka

2015-01-01

Exposure to the trauma memory is the common denominator of most evidence-based interventions for posttraumatic stress disorder (PTSD). Although exposure-based therapies aim to change associative learning networks and negative cognitions related to the trauma memory, emotional interactions between patient and therapist have not been thoroughly considered in past evaluations of exposure-based therapy. This work focuses on recent discoveries of the mirror-neuron system and the theory of embodied simulation (ES). These conceptualizations may add a new perspective to our understanding of change processes in exposure-based treatments for PTSD patients. It is proposed that during exposure to trauma memories, emotional responses of the patient are transferred to the therapist through ES and then mirrored back to the patient in a modulated way. This process helps to alleviate the patient's sense of loneliness and enhances his or her ability to exert control over painful, trauma-related emotional responses. ES processes may enhance the integration of clinical insights originating in psychoanalytic theories—such as holding, containment, projective identification, and emotional attunement—with cognitive behavioral theories of learning processes in the alleviation of painful emotional responses aroused by trauma memories. These processes are demonstrated through a clinical vignette from an exposure-based therapy with a trauma survivor. Possible clinical implications for the importance of face-to-face relationships during exposure-based therapy are discussed. PMID:26593097

Embodied simulation in exposure-based therapies for posttraumatic stress disorder-a possible integration of cognitive behavioral theories, neuroscience, and psychoanalysis.

PubMed

Peri, Tuvia; Gofman, Mordechai; Tal, Shahar; Tuval-Mashiach, Rivka

2015-01-01

Exposure to the trauma memory is the common denominator of most evidence-based interventions for posttraumatic stress disorder (PTSD). Although exposure-based therapies aim to change associative learning networks and negative cognitions related to the trauma memory, emotional interactions between patient and therapist have not been thoroughly considered in past evaluations of exposure-based therapy. This work focuses on recent discoveries of the mirror-neuron system and the theory of embodied simulation (ES). These conceptualizations may add a new perspective to our understanding of change processes in exposure-based treatments for PTSD patients. It is proposed that during exposure to trauma memories, emotional responses of the patient are transferred to the therapist through ES and then mirrored back to the patient in a modulated way. This process helps to alleviate the patient's sense of loneliness and enhances his or her ability to exert control over painful, trauma-related emotional responses. ES processes may enhance the integration of clinical insights originating in psychoanalytic theories-such as holding, containment, projective identification, and emotional attunement-with cognitive behavioral theories of learning processes in the alleviation of painful emotional responses aroused by trauma memories. These processes are demonstrated through a clinical vignette from an exposure-based therapy with a trauma survivor. Possible clinical implications for the importance of face-to-face relationships during exposure-based therapy are discussed.

Gamma band plasticity in sensory cortex is a signature of the strongest memory rather than memory of the training stimulus.

PubMed

Weinberger, Norman M; Miasnikov, Alexandre A; Bieszczad, Kasia M; Chen, Jemmy C

2013-09-01

Gamma oscillations (∼30-120Hz) are considered to be a reflection of coordinated neuronal activity, linked to processes underlying synaptic integration and plasticity. Increases in gamma power within the cerebral cortex have been found during many cognitive processes such as attention, learning, memory and problem solving in both humans and animals. However, the specificity of gamma to the detailed contents of memory remains largely unknown. We investigated the relationship between learning-induced increased gamma power in the primary auditory cortex (A1) and the strength of memory for acoustic frequency. Adult male rats (n=16) received three days (200 trials each) of pairing a tone (3.66 kHz) with stimulation of the nucleus basalis, which implanted a memory for acoustic frequency as assessed by associatively-induced disruption of ongoing behavior, viz., respiration. Post-training frequency generalization gradients (FGGs) revealed peaks at non-CS frequencies in 11/16 cases, likely reflecting normal variation in pre-training acoustic experiences. A stronger relationship was found between increased gamma power and the frequency with the strongest memory (peak of the difference between individual post- and pre-training FGGs) vs. behavioral responses to the CS training frequency. No such relationship was found for the theta/alpha band (4-15 Hz). These findings indicate that the strength of specific increased neuronal synchronization within primary sensory cortical fields can determine the specific contents of memory. Copyright © 2013 Elsevier Inc. All rights reserved.

GAMMA BAND PLASTICITY IN SENSORY CORTEX IS A SIGNATURE OF THE STRONGEST MEMORY RATHER THAN MEMORY OF THE TRAINING STIMULUS

PubMed Central

Weinberger, Norman M.; Miasnikov, Alexandre A.; Bieszczad, Kasia M.; Chen, Jemmy C.

2013-01-01

Gamma oscillations (~30–120 Hz) are considered to be a reflection of coordinated neuronal activity, linked to processes underlying synaptic integration and plasticity. Increases in gamma power within the cerebral cortex have been found during many cognitive processes such as attention, learning, memory and problem solving in both humans and animals. However, the specificity of gamma to the detailed contents of memory remains largely unknown. We investigated the relationship between learning-induced increased gamma power in the primary auditory cortex (A1) and the strength of memory for acoustic frequency. Adult male rats (n = 16) received three days (200 trials each) of pairing a tone (3.66 kHz) with stimulation of the nucleus basalis, which implanted a memory for acoustic frequency as assessed by associatively-induced disruption of ongoing behavior, viz., respiration. Post-training frequency generalization gradients (FGGs) revealed peaks at non-CS frequencies in 11/16 cases, likely reflecting normal variation in pre-training acoustic experiences. A stronger relationship was found between increased gamma power and the frequency with the strongest memory (peak of the difference between individual post- and pre-training FGGs) vs. behavioral responses to the CS training frequency. No such relationship was found for the theta/alpha band (4–15 Hz). These findings indicate that the strength of specific increased neuronal synchronization within primary sensory cortical fields can determine the specific contents of memory. PMID:23669065

[The role of synaptic transmission in memory and neurodegeneration processes and effects of neurotropic preparations].

PubMed

Voronina, T A

2003-01-01

Academician Zakusov, in his book Pharmacology of Central Synapses (Moscow, 1973), emphasized the central role of synaptic processes in regulation of various forms of behavior, memory, and psychotropic drug action. The paper considers most promising directions in the search for substances possessing nootropic and neuroprotector properties, many of which were developed at the Institute of Pharmacology based on the notion about synaptic processes. These investigations led to the creation of well-known drugs such as mexidole, noopept, nooglutyl, beglimin, etc. Special attention is devoted to the implementation and modern development of the ideas of Academician Zakusov. Recent data are presented on the role of neuropeptides, neurotrophins, and intracellular signaling mechanisms in synaptic plasticity, memory processes, and development of neurodegenerative states.

Working memory retrieval as a decision process

PubMed Central

Pearson, Benjamin; Raškevičius, Julius; Bays, Paul M.; Pertzov, Yoni; Husain, Masud

2014-01-01

Working memory (WM) is a core cognitive process fundamental to human behavior, yet the mechanisms underlying it remain highly controversial. Here we provide a new framework for understanding retrieval of information from WM, conceptualizing it as a decision based on the quality of internal evidence. Recent findings have demonstrated that precision of WM decreases with memory load. If WM retrieval uses a decision process that depends on memory quality, systematic changes in response time distribution should occur as a function of WM precision. We asked participants to view sample arrays and, after a delay, report the direction of change in location or orientation of a probe. As WM precision deteriorated with increasing memory load, retrieval time increased systematically. Crucially, the shape of reaction time distributions was consistent with a linear accumulator decision process. Varying either task relevance of items or maintenance duration influenced memory precision, with corresponding shifts in retrieval time. These results provide strong support for a decision-making account of WM retrieval based on noisy storage of items. Furthermore, they show that encoding, maintenance, and retrieval in WM need not be considered as separate processes, but may instead be conceptually unified as operations on the same noise-limited, neural representation. PMID:24492597

Working memory retrieval as a decision process.

PubMed

Pearson, Benjamin; Raskevicius, Julius; Bays, Paul M; Pertzov, Yoni; Husain, Masud

2014-02-03

Working memory (WM) is a core cognitive process fundamental to human behavior, yet the mechanisms underlying it remain highly controversial. Here we provide a new framework for understanding retrieval of information from WM, conceptualizing it as a decision based on the quality of internal evidence. Recent findings have demonstrated that precision of WM decreases with memory load. If WM retrieval uses a decision process that depends on memory quality, systematic changes in response time distribution should occur as a function of WM precision. We asked participants to view sample arrays and, after a delay, report the direction of change in location or orientation of a probe. As WM precision deteriorated with increasing memory load, retrieval time increased systematically. Crucially, the shape of reaction time distributions was consistent with a linear accumulator decision process. Varying either task relevance of items or maintenance duration influenced memory precision, with corresponding shifts in retrieval time. These results provide strong support for a decision-making account of WM retrieval based on noisy storage of items. Furthermore, they show that encoding, maintenance, and retrieval in WM need not be considered as separate processes, but may instead be conceptually unified as operations on the same noise-limited, neural representation.

ADHD and working memory: the impact of central executive deficits and exceeding storage/rehearsal capacity on observed inattentive behavior.

PubMed

Kofler, Michael J; Rapport, Mark D; Bolden, Jennifer; Sarver, Dustin E; Raiker, Joseph S

2010-02-01

Inattentive behavior is considered a core and pervasive feature of ADHD; however, an alternative model challenges this premise and hypothesizes a functional relationship between working memory deficits and inattentive behavior. The current study investigated whether inattentive behavior in children with ADHD is functionally related to the domain-general central executive and/or subsidiary storage/rehearsal components of working memory. Objective observations of children's attentive behavior by independent observers were conducted while children with ADHD (n = 15) and typically developing children (n = 14) completed counterbalanced tasks that differentially manipulated central executive, phonological storage/rehearsal, and visuospatial storage/rehearsal demands. Results of latent variable and effect size confidence interval analyses revealed two conditions that completely accounted for the attentive behavior deficits in children with ADHD: (a) placing demands on central executive processing, the effect of which is evident under even low cognitive loads, and (b) exceeding storage/rehearsal capacity, which has similar effects on children with ADHD and typically developing children but occurs at lower cognitive loads for children with ADHD.

Characterizing neurocognitive late effects in childhood leukemia survivors using a combination of neuropsychological and cognitive neuroscience measures.

PubMed

Van Der Plas, Ellen; Erdman, Lauren; Nieman, Brian J; Weksberg, Rosanna; Butcher, Darci T; O'connor, Deborah L; Aufreiter, Susanne; Hitzler, Johann; Guger, Sharon L; Schachar, Russell J; Ito, Shinya; Spiegler, Brenda J

2017-10-10

Knowledge about cognitive late effects in survivors of childhood acute lymphoblastic leukemia (ALL) is largely based on standardized neuropsychological measures and parent reports. To examine whether cognitive neuroscience paradigms provided additional insights into neurocognitive and behavioral late effects in ALL survivors, we assessed cognition and behavior using a selection of cognitive neuroscience tasks and standardized measures probing domains previously demonstrated to be affected by chemotherapy. 130 ALL survivors and 158 control subjects, between 8 and 18 years old at time of testing, completed the n-back (working memory) and stop-signal (response inhibition) tasks. ALL survivors also completed standardized measures of intelligence (Wechsler Intelligence Scales [WISC-IV]), motor skills (Grooved Pegboard), math abilities (WIAT-III), and executive functions (Delis-Kaplan Executive Function System). Parents completed behavioral measures of executive functions (Behavior Rating Inventory of Executive Function [BRIEF]) and attention (Conners-3). ALL survivors exhibited deficiencies in working memory and response inhibition compared with controls. ALL survivors also exhibited deficits on WISC-IV working memory and processing speed, Grooved Pegboard, WIAT-III addition and subtraction fluency, and numerical operations, as well as DKEFS number-letter switching. Parent reports suggested more attention deficits (Conners-3) and behavioral difficulties (BRIEF) in ALL survivors compared with referenced norms. Low correspondence between standardized and experimental measures of working memory and response inhibition was noted. The use of cognitive neuroscience paradigms complements our understanding of the cognitive deficits evident after treatment of ALL. These measures could further delineate cognitive processes involved in neurocognitive late effects, providing opportunities to explore their underlying mechanisms.

Obese adolescents with type 2 diabetes perform worse than controls on cognitive and behavioral assessments.

PubMed

Brady, Cassandra C; Vannest, Jennifer J; Dolan, Lawrence M; Kadis, Darren S; Lee, Gregory R; Holland, Scott K; Khoury, Jane C; Shah, Amy S

2017-06-01

Children with type 1 diabetes demonstrate worse cognitive performance compared with their peers. Little is known regarding the cognitive and behavioral performance in obese adolescents with type 2 diabetes. Cross sectional evaluation of 20 obese adolescents with type 2 diabetes and 20 healthy adolescents was performed in Cincinnati, Ohio. Cognitive tests that included measures of processing speed, working memory, verbal and semantic fluency and parent reports of executive function and problem behavior were compared. Academic achievement and the relationship between cognitive/behavioral scores and diabetes duration and diabetes control (hemoglobin A1c) were assessed in the type 2 diabetes group only. The type 2 diabetes group had mean duration of diabetes of 2.8 ± 2.2 yr and hemoglobin A1c of 7.9 ± 2.2%. Adolescents with type 2 diabetes scored lower than controls on tests of working and verbal memory and processing speed (all p < 0.05) and worse for Internalizing, Externalizing, and Total Problems behaviors on the Child Behavior Checklist (all p < 0.05). Adolescents with type 2 diabetes scored below the population mean in academic achievement, most notably calculation. Working memory and processing speed were negatively correlated with duration of diabetes (r = -0.50 and -0.47, respectively, p < 0.05). Obese youth with type 2 diabetes score poorly compared with controls on multiple assessments of cognitive function and adaptive behavior. Further work is needed to determine if these effects are driven by obesity, diabetes or other demographic and socioeconomic risk factors. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Dreaming of a Learning Task is Associated with Enhanced Sleep-Dependent Memory Consolidation

PubMed Central

Wamsley, Erin J.; Tucker, Matthew; Payne, Jessica D.; Benavides, Joseph; Stickgold, Robert

2010-01-01

Summary It is now well established that post-learning sleep is beneficial for human memory performance [1–5]. Meanwhile, human and animal studies demonstrate that learning-related neural activity is re-expressed during post-training non-rapid eye movement sleep (NREM) [6–9]. NREM sleep processes appear to be particularly beneficial for hippocampus-dependent forms of memory [1–3, 10]. These observations suggest that learning triggers the reactivation and reorganization of memory traces during sleep, a systems-level process that in turn enhances behavioral performance. Here, we hypothesized that dreaming about a learning experience during NREM sleep would be associated with improved performance on a hippocampus-dependent spatial memory task. Subjects (n=99) were trained on a virtual navigation task, and then retested on the same task 5 hours after initial training. Improved performance at retest was strongly associated with task-related dream imagery during an intervening afternoon nap. Task-related thoughts during wakefulness, in contrast, did not predict improved performance. These observations suggest that sleep-dependent memory consolidation in humans is facilitated by the offline reactivation of recently formed memories, and furthermore, that dream experiences reflect this memory processing. That similar effects were not seen during wakefulness suggests that these mnemonic processes are specific to the sleep state. PMID:20417102

Memory as behavior: The importance of acquisition and remembering strategies

PubMed Central

Delaney, Peter F.; Austin, John

1998-01-01

The study of memory has traditionally been the province of cognitive psychology, which has postulated different memory systems that store memory traces to explain remembering. Behavioral psychologists have been unsuccessful at empirically identifying the behavior that occurs during remembering because so much of it occurs rapidly and covertly. In addition, behavior analysts have generally been disinterested in studying transient phenomena such as memory. As a result, the cognitive interpretation has been the only one that has made and tested useful predictions. Recent experimental evidence acquired while having participants “think aloud” suggests that a behavioral approach to memory may provide a superior account of memory performance and allow applied scientists to observe and modify memory-related behavior with well-known applied behavior-analytic techniques. We review evidence supporting and extending the interpretation of memory provided by Palmer (1991), who described memory in terms of precurrent behavior that occurs at the time of acquisition in preparation for problem solving that occurs at the time of remembering. ImagesFig. 1 PMID:22477129

The effects of aging on ERP correlates of source memory retrieval for self-referential information.

PubMed

Dulas, Michael R; Newsome, Rachel N; Duarte, Audrey

2011-03-04

Numerous behavioral studies have suggested that normal aging negatively affects source memory accuracy for various kinds of associations. Neuroimaging evidence suggests that less efficient retrieval processing (temporally delayed and attenuated) may contribute to these impairments. Previous aging studies have not compared source memory accuracy and corresponding neural activity for different kinds of source details; namely, those that have been encoded via a more or less effective strategy. Thus, it is not yet known whether encoding source details in a self-referential manner, a strategy suggested to promote successful memory in the young and old, may enhance source memory accuracy and reduce the commonly observed age-related changes in neural activity associated with source memory retrieval. Here, we investigated these issues by using event-related potentials (ERPs) to measure the effects of aging on the neural correlates of successful source memory retrieval ("old-new effects") for objects encoded either self-referentially or self-externally. Behavioral results showed that both young and older adults demonstrated better source memory accuracy for objects encoded self-referentially. ERP results showed that old-new effects onsetted earlier for self-referentially encoded items in both groups and that age-related differences in the onset latency of these effects were reduced for self-referentially, compared to self-externally, encoded items. These results suggest that the implementation of an effective encoding strategy, like self-referential processing, may lead to more efficient retrieval, which in turn may improve source memory accuracy in both young and older adults. Published by Elsevier B.V.

Spray forming of NiTi and NiTiPd shape-memory alloys

NASA Astrophysics Data System (ADS)

Smith, Ronald; Mabe, James; Ruggeri, Robert; Noebe, Ronald

2008-03-01

In the work to be presented, vacuum plasma spray forming has been used as a process to deposit and consolidate prealloyed NiTi and NiTiPd powders into near net shape actuators. Testing showed that excellent shape memory behavior could be developed in the deposited materials and the investigation proved that VPS forming could be a means to directly form a wide range of shape memory alloy components. The results of DSC characterization and actual actuation test results will be presented demonstrating the behavior of a Nitinol 55 alloy and a higher transition temperature NiTiPd alloy in the form of torque tube actuators that could be used in aircraft and aerospace controls.

Spray Forming of NiTi and NiTiPd Shape-Memory Alloys

NASA Technical Reports Server (NTRS)

Mabe, James; Ruggeri, Robert; Noebe, Ronald

2008-01-01

In the work to be presented, vacuum plasma spray forming has been used as a process to deposit and consolidate prealloyed NiTi and NiTiPd powders into near net shape actuators. Testing showed that excellent shape memory behavior could be developed in the deposited materials and the investigation proved that VPS forming could be a means to directly form a wide range of shape memory alloy components. The results of DSC characterization and actual actuation test results will be presented demonstrating the behavior of a Nitinol 55 alloy and a higher transition temperature NiTiPd alloy in the form of torque tube actuators that could be used in aircraft and aerospace controls.

Complex Networks in Psychological Models

NASA Astrophysics Data System (ADS)

Wedemann, R. S.; Carvalho, L. S. A. V. D.; Donangelo, R.

We develop schematic, self-organizing, neural-network models to describe mechanisms associated with mental processes, by a neurocomputational substrate. These models are examples of real world complex networks with interesting general topological structures. Considering dopaminergic signal-to-noise neuronal modulation in the central nervous system, we propose neural network models to explain development of cortical map structure and dynamics of memory access, and unify different mental processes into a single neurocomputational substrate. Based on our neural network models, neurotic behavior may be understood as an associative memory process in the brain, and the linguistic, symbolic associative process involved in psychoanalytic working-through can be mapped onto a corresponding process of reconfiguration of the neural network. The models are illustrated through computer simulations, where we varied dopaminergic modulation and observed the self-organizing emergent patterns at the resulting semantic map, interpreting them as different manifestations of mental functioning, from psychotic through to normal and neurotic behavior, and creativity.

The effect of magnetic field on shape memory behavior in Heusler-type nickel(,2)manganese-gallium-based compounds

NASA Astrophysics Data System (ADS)

Jeong, Soon-Jong

2000-08-01

Shape memory alloys (SMAs) have excellent mechanical properties showing large stroke and high power density when used as actuators. In terms of response speed, however, conventional SMAs have a drawback due to the isothermal nature of the associated phase transformation. A new type of SMA, called ferromagnetic SMA, is considered to replace conventional SMAs and is hoped to overcome such a slow response drawback by changing driving mode of shape memory behaviors from thermal to magnetic. The new type of ferromagnetic SMAs is expected to exhibit not only a large displacement but also rapid response when magnetic field is applied and removed. There are three kinds of ferromagnetic SMAs and among them, Ni2MnGa-based compounds exhibit prominent shape memory effects and superelasticity. In this study, Ni2MnGa-based alloys were chosen and studied to characterize shape memory behavior upon the application and removal of magnetic field. The relevance of the magnetic field-induced shape memory behavior to the magnetization process was investigated by using transformation and/or the movement of martensite variant interfaces. Two mechanisms have been proposed for controlling magnetic field-induced shape memory behaviors. One mechanism is related to shape memory behavior associated with magnetic field-induced martensitic transformation. The other is related to the rearrangement of martensite variants by magnetic field application. Magnetic field-induced martensitic transformation and shape memory effects for single- and poly-crystalline Ni2MnGa alloys were investigated under various conditions. In single crystalline specimens, it was observed that considerable strain changes are a function of magnetic field at temperatures below Mf (martensite finish temperature). Such strain changes, by application and subsequent removal of magnetic field, may be attributed to the martensite variant motion at lower temperatures than Mf. Magnetic field application made a significant contribution to the martensite transformation and related strain changes (0.3%--0.82%) at temperatures above Af (austenite finish temperature) in some polycrystalline Ni2MnGa alloys, where austenite and martensite phases possess paramagnetic and ferromagnetic properties, respectively.

Bridging consciousness and cognition in memory and perception: evidence for both state and strength processes.

PubMed

Aly, Mariam; Yonelinas, Andrew P

2012-01-01

Subjective experience indicates that mental states are discrete, in the sense that memories and perceptions readily come to mind in some cases, but are entirely unavailable to awareness in others. However, a long history of psychophysical research has indicated that the discrete nature of mental states is largely epiphenomenal and that mental processes vary continuously in strength. We used a novel combination of behavioral methodologies to examine the processes underlying perception of complex images: (1) analysis of receiver operating characteristics (ROCs), (2) a modification of the change-detection flicker paradigm, and (3) subjective reports of conscious experience. These methods yielded converging results showing that perceptual judgments reflect the combined, yet functionally independent, contributions of two processes available to conscious experience: a state process of conscious perception and a strength process of knowing; processes that correspond to recollection and familiarity in long-term memory. In addition, insights from the perception experiments led to the discovery of a new recollection phenomenon in a long-term memory change detection paradigm. The apparent incompatibility between subjective experience and theories of cognition can be understood within a unified state-strength framework that links consciousness to cognition across the domains of perception and memory.

Bridging Consciousness and Cognition in Memory and Perception: Evidence for Both State and Strength Processes

PubMed Central

Aly, Mariam; Yonelinas, Andrew P.

2012-01-01

Subjective experience indicates that mental states are discrete, in the sense that memories and perceptions readily come to mind in some cases, but are entirely unavailable to awareness in others. However, a long history of psychophysical research has indicated that the discrete nature of mental states is largely epiphenomenal and that mental processes vary continuously in strength. We used a novel combination of behavioral methodologies to examine the processes underlying perception of complex images: (1) analysis of receiver operating characteristics (ROCs), (2) a modification of the change-detection flicker paradigm, and (3) subjective reports of conscious experience. These methods yielded converging results showing that perceptual judgments reflect the combined, yet functionally independent, contributions of two processes available to conscious experience: a state process of conscious perception and a strength process of knowing; processes that correspond to recollection and familiarity in long-term memory. In addition, insights from the perception experiments led to the discovery of a new recollection phenomenon in a long-term memory change detection paradigm. The apparent incompatibility between subjective experience and theories of cognition can be understood within a unified state-strength framework that links consciousness to cognition across the domains of perception and memory. PMID:22272314

Interaction between basal ganglia and limbic circuits in learning and memory processes.

PubMed

Calabresi, Paolo; Picconi, Barbara; Tozzi, Alessandro; Ghiglieri, Veronica

2016-01-01

Hippocampus and striatum play distinctive roles in memory processes since declarative and non-declarative memory systems may act independently. However, hippocampus and striatum can also be engaged to function in parallel as part of a dynamic system to integrate previous experience and adjust behavioral responses. In these structures the formation, storage, and retrieval of memory require a synaptic mechanism that is able to integrate multiple signals and to translate them into persistent molecular traces at both the corticostriatal and hippocampal/limbic synapses. The best cellular candidate for this complex synthesis is represented by long-term potentiation (LTP). A common feature of LTP expressed in these two memory systems is the critical requirement of convergence and coincidence of glutamatergic and dopaminergic inputs to the dendritic spines of the neurons expressing this form of synaptic plasticity. In experimental models of Parkinson's disease abnormal accumulation of α-synuclein affects these two memory systems by altering two major synaptic mechanisms underlying cognitive functions in cholinergic striatal neurons, likely implicated in basal ganglia dependent operative memory, and in the CA1 hippocampal region, playing a central function in episodic/declarative memory processes. Copyright © 2015 Elsevier Ltd. All rights reserved.

Behavioral Performance and Neural Areas Associated with Memory Processes Contribute to Math and Reading Achievement in 6-year-old Children.

PubMed

Blankenship, Tashauna L; Keith, Kayla; Calkins, Susan D; Bell, Martha Ann

2018-01-01

Associations between working memory and academic achievement (math and reading) are well documented. Surprisingly, little is known of the contributions of episodic memory, segmented into temporal memory (recollection proxy) and item recognition (familiarity proxy), to academic achievement. This is the first study to observe these associations in typically developing 6-year old children. Overlap in neural correlates exists between working memory, episodic memory, and math and reading achievement. We attempted to tease apart the neural contributions of working memory, temporal memory, and item recognition to math and reading achievement. Results suggest that working memory and temporal memory, but not item recognition, are important contributors to both math and reading achievement, and that EEG power during a working memory task contributes to performance on tests of academic achievement.

The Effects of Caffeine on Memory for Word Lists.

ERIC Educational Resources Information Center

Erikson, George; And Others

Research has suggested that behavioral differences may account for the effects of caffeine on information processing. To investigate the effects of caffeine on memory for supraspan word lists, 107 college students (47 males, 60 females), divided into 12 groups by high and low impulsivity scores on the Eysenck Personality Inventory, participated in…

The Anaphase Promoting Complex Is Required for Memory Function in Mice

ERIC Educational Resources Information Center

Kuczera, Tanja; Stilling, Roman Manuel; Hsia, Hung-En; Bahari-Javan, Sanaz; Irniger, Stefan; Nasmyth, Kim; Sananbenesi, Farahnaz; Fischer, Andre

2011-01-01

Learning and memory processes critically involve the orchestrated regulation of de novo protein synthesis. On the other hand it has become clear that regulated protein degradation also plays a major role in neuronal plasticity and learning behavior. One of the key pathways mediating protein degradation is proteosomal protein destruction. The…

Neural Correlates of the In-Group Memory Advantage on the Encoding and Recognition of Faces

PubMed Central

Herzmann, Grit; Curran, Tim

2013-01-01

People have a memory advantage for faces that belong to the same group, for example, that attend the same university or have the same personality type. Faces from such in-group members are assumed to receive more attention during memory encoding and are therefore recognized more accurately. Here we use event-related potentials related to memory encoding and retrieval to investigate the neural correlates of the in-group memory advantage. Using the minimal group procedure, subjects were classified based on a bogus personality test as belonging to one of two personality types. While the electroencephalogram was recorded, subjects studied and recognized faces supposedly belonging to the subject’s own and the other personality type. Subjects recognized in-group faces more accurately than out-group faces but the effect size was small. Using the individual behavioral in-group memory advantage in multivariate analyses of covariance, we determined neural correlates of the in-group advantage. During memory encoding (300 to 1000 ms after stimulus onset), subjects with a high in-group memory advantage elicited more positive amplitudes for subsequently remembered in-group than out-group faces, showing that in-group faces received more attention and elicited more neural activity during initial encoding. Early during memory retrieval (300 to 500 ms), frontal brain areas were more activated for remembered in-group faces indicating an early detection of group membership. Surprisingly, the parietal old/new effect (600 to 900 ms) thought to indicate recollection processes differed between in-group and out-group faces independent from the behavioral in-group memory advantage. This finding suggests that group membership affects memory retrieval independent of memory performance. Comparisons with a previous study on the other-race effect, another memory phenomenon influenced by social classification of faces, suggested that the in-group memory advantage is dominated by top-down processing whereas the other-race effect is also influenced by extensive perceptual experience. PMID:24358226

Pathways to Third-Grade Calculation versus Word-Reading Competence: Are They More Alike or Different?

PubMed Central

Fuchs, Lynn S.; Geary, David C.; Fuchs, Douglas; Compton, Donald L.; Hamlett, Carol L.

2015-01-01

Children (n=747; 6.5 years) were assessed on domain-general processes and mathematics and reading-related competencies (start of 1st grade); addition retrieval (end of 2nd grade); and calculations and word reading (end of 3rd grade). Attentive behavior, reasoning, visuospatial memory, and rapid automatized naming (RAN) indirectly contributed to both outcomes, via retrieval. However, there was no overlap in domain-general direct effects on calculations (attentive behavior, reasoning, working memory) versus word reading (language, phonological memory, RAN). Results suggest ease of forming associative relations and abilities engaged during the formation of these long-term memories are common to both outcomes and can be indexed by addition fact retrieval, but further growth in calculations and word reading is driven by different constellations of domain-general abilities. PMID:26700885

The extended trajectory of hippocampal development: implications for early memory development and disorder

PubMed Central

Gómez, Rebecca L.; Edgin, Jamie O.

2015-01-01

Hippocampus has an extended developmental trajectory, with refinements occurring in the trisynaptic circuit until adolescence. While structural change should suggest a protracted course in behavior, some studies find evidence of precocious hippocampal development in the first postnatal year and continuity in memory processes beyond. However, a number of memory functions, including binding and relational inference, can be cortically supported. Evidence from the animal literature suggests that tasks often associated with hippocampus (Visual Paired Comparison, binding of a visuomotor response) can be mediated by structures external to hippocampus. Thus, a complete examination of memory development will have to rule out cortex as a source of early memory competency. We propose that early memory must show properties associated with full function of the trisynaptic circuit to reflect “adult-like” memory function, mainly 1) rapid encoding of contextual details of overlapping patterns, and 2) retention of these details over sleep-dependent delays. A wealth of evidence suggests that these functions are not apparent until 18–24 months, with behavioral discontinuities reflecting shifts in the neural structures subserving memory beginning approximately at this point in development. We discuss the implications of these observations for theories of memory and for identifying and measuring memory function in populations with typical and atypical hippocampal function. PMID:26437910

Humidity-activated shape memory effect on plasticized starch-based biomaterials.

PubMed

Sessini, Valentina; Arrieta, Marina P; Fernández-Torres, Alberto; Peponi, Laura

2018-01-01

Humidity-activated shape memory behavior of plasticized starch-based films reinforced with the innovative combination of starch nanocrystals (SNCs) and catechin as antioxidant were studied. In a previous work, we reported the processing of gelatinized starch-based films filled with SNCs and catechin as antioxidant agent, and we observed that this novel combination leads to starch-based film with enhanced thermal and mechanical performance. In this work, the humidity-activated shape memory behavior of the previous developed starch-based films was characterized. The moisture loss as well as the moisture absorption were studied since they are essential parameters in humidity-activated shape memory polymers to fix the temporary shape and to recover the original shape, respectively. Therefore, the effect of the incorporation of SNCs and catechin on the humidity-activated shape memory properties of plasticized starch was also studied. Moreover, the effectiveness of catechin to increase the polymer stability under oxidative atmosphere and the thermo-mechanical relaxation of all the starch-based materials were studied. The combination of plasticized starch matrix loaded with both, SNCs and catechin, leads to a multifunctional starch-based films with increased hydrophilicity and with excellent humidity-activated shape memory behavior with interest for potential biomedical applications. Copyright © 2017 Elsevier Ltd. All rights reserved.

Nonstationary signal analysis in episodic memory retrieval

NASA Astrophysics Data System (ADS)

Ku, Y. G.; Kawasumi, Masashi; Saito, Masao

2004-04-01

The problem of blind source separation from a mixture that has nonstationarity can be seen in signal processing, speech processing, spectral analysis and so on. This study analyzed EEG signal during episodic memory retrieval using ICA and TVAR. This paper proposes a method which combines ICA and TVAR. The signal from the brain not only exhibits the nonstationary behavior, but also contain artifacts. EEG data at the frontal lobe (F3) from the scalp is collected during the episodic memory retrieval task. The method is applied to EEG data for analysis. The artifact (eye movement) is removed by ICA, and a single burst (around 6Hz) is obtained by TVAR, suggesting that the single burst is related to the brain activity during the episodic memory retrieval.

Sleep Improves Prospective Remembering by Facilitating Spontaneous-Associative Retrieval Processes

PubMed Central

Diekelmann, Susanne; Wilhelm, Ines; Wagner, Ullrich; Born, Jan

2013-01-01

Memories are of the past but for the future, enabling individuals to implement intended plans and actions at the appropriate time. Prospective memory is the specific ability to remember and execute an intended behavior at some designated point in the future. Although sleep is well-known to benefit the consolidation of memories for past events, its role for prospective memory is still not well understood. Here, we show that sleep as compared to wakefulness after prospective memory instruction enhanced the successful execution of prospective memories two days later. We further show that sleep benefited both components of prospective memory, i.e. to remember that something has to be done (prospective component) and to remember what has to be done (retrospective component). Finally, sleep enhanced prospective remembering particularly when attentional resources were reduced during task execution, suggesting that subjects after sleep were able to recruit additional spontaneous-associative retrieval processes to remember intentions successfully. Our findings indicate that sleep supports the maintenance of prospective memory over time by strengthening intentional memory representations, thus favoring the spontaneous retrieval of the intended action at the appropriate time. PMID:24143246

Circadian modulation of short-term memory in Drosophila.

PubMed

Lyons, Lisa C; Roman, Gregg

2009-01-01

Endogenous biological clocks are widespread regulators of behavior and physiology, allowing for a more efficient allocation of efforts and resources over the course of a day. The extent that different processes are regulated by circadian oscillators, however, is not fully understood. We investigated the role of the circadian clock on short-term associative memory formation using a negatively reinforced olfactory-learning paradigm in Drosophila melanogaster. We found that memory formation was regulated in a circadian manner. The peak performance in short-term memory (STM) occurred during the early subjective night with a twofold performance amplitude after a single pairing of conditioned and unconditioned stimuli. This rhythm in memory is eliminated in both timeless and period mutants and is absent during constant light conditions. Circadian gating of sensory perception does not appear to underlie the rhythm in short-term memory as evidenced by the nonrhythmic shock avoidance and olfactory avoidance behaviors. Moreover, central brain oscillators appear to be responsible for the modulation as cryptochrome mutants, in which the antennal circadian oscillators are nonfunctional, demonstrate robust circadian rhythms in short-term memory. Together these data suggest that central, rather than peripheral, circadian oscillators modulate the formation of short-term associative memory and not the perception of the stimuli.

Prenatal Stress Impairs Spatial Learning and Memory Associated with Lower mRNA Level of the CAMKII and CREB in the Adult Female Rat Hippocampus.

PubMed

Sun, Hongli; Wu, Haibin; Liu, Jianping; Wen, Jun; Zhu, Zhongliang; Li, Hui

2017-05-01

Prenatal stress (PS) results in various behavioral and emotional alterations observed in later life. In particular, PS impairs spatial learning and memory processes but the underlying mechanism involved in this pathogenesis still remains unknown. Here, we reported that PS lowered the body weight in offspring rats, particularly in female rats, and impaired spatial learning and memory of female offspring rats in the Morris water maze. Correspondingly, the decreased CaMKII and CREB mRNA in the hippocampus were detected in prenatally stressed female offspring, which partially explained the effect of PS on the spatial learning and memory. Our findings suggested that CaMKII and CREB may be involved in spatial learning and memory processes in the prenatally stressed adult female offspring.

Neural correlates of retrieval-based memory enhancement: An fMRI study of the testing effect

PubMed Central

Wing, Erik A.; Marsh, Elizabeth J.; Cabeza, Roberto

2013-01-01

Restudying material is a common method for learning new information, but not necessarily an effective one. Research on the testing effect shows that practice involving retrieval from memory can facilitate later memory in contrast to passive restudy. Despite extensive behavioral work, the brain processes that make retrieval an effective learning strategy remain unclear. In the present experiment, we explored how initially retrieving items affected memory a day later as compared to a condition involving traditional restudy. In contrast to restudy, initial testing that contributed to future memory success was associated with engagement of several regions including the anterior hippocampus, lateral temporal cortices, and medial prefrontal cortex (PFC). Additionally, testing enhanced hippocampal connectivity with ventrolateral PFC and midline regions. These findings indicate that the testing effect may be contingent on processes that are typically thought to support memory success at encoding (e.g. relational binding, selection and elaboration of semantically-related information) in addition to those more often associated with retrieval (e.g. memory search). PMID:23607935

Memory Interference as a Determinant of Language Comprehension

PubMed Central

Van Dyke, Julie A.; Johns, Clinton L.

2012-01-01

The parameters of the human memory system constrain the operation of language comprehension processes. In the memory literature, both decay and interference have been proposed as causes of forgetting; however, while there is a long history of research establishing the nature of interference effects in memory, the effects of decay are much more poorly supported. Nevertheless, research investigating the limitations of the human sentence processing mechanism typically focus on decay-based explanations, emphasizing the role of capacity, while the role of interference has received comparatively little attention. This paper reviews both accounts of difficulty in language comprehension by drawing direct connections to research in the memory domain. Capacity-based accounts are found to be untenable, diverging substantially from what is known about the operation of the human memory system. In contrast, recent research investigating comprehension difficulty using a retrieval-interference paradigm is shown to be wholly consistent with both behavioral and neuropsychological memory phenomena. The implications of adopting a retrieval-interference approach to investigating individual variation in language comprehension are discussed. PMID:22773927

New learning following reactivation in the human brain: targeting emotional memories through rapid serial visual presentation.

PubMed

Wirkner, Janine; Löw, Andreas; Hamm, Alfons O; Weymar, Mathias

2015-03-01

Once reactivated, previously consolidated memories destabilize and have to be reconsolidated to persist, a process that might be altered non-invasively by interfering learning immediately after reactivation. Here, we investigated the influence of interference on brain correlates of reactivated episodic memories for emotional and neutral scenes using event-related potentials (ERPs). To selectively target emotional memories we applied a new reactivation method: rapid serial visual presentation (RSVP). RSVP leads to enhanced implicit processing (pop out) of the most salient memories making them vulnerable to disruption. In line, interference after reactivation of previously encoded pictures disrupted recollection particularly for emotional events. Furthermore, memory impairments were reflected in a reduced centro-parietal ERP old/new difference during retrieval of emotional pictures. These results provide neural evidence that emotional episodic memories in humans can be selectively altered through behavioral interference after reactivation, a finding with further clinical implications for the treatment of anxiety disorders. Copyright © 2015 Elsevier Inc. All rights reserved.

Developing Rational-Empirical Views of Intelligent Adaptive Behavior

DTIC Science & Technology

2004-08-01

biological frame to the information processing model and outline our understanding of intentions and beliefs that co-exist with rational and...notion that the evolution of cognition has produced memory/ knowledge systems that specialize in the processing of particular types of information ...1 PERMIS 2004 Developing Rational-Empirical Views of Intelligent Adaptive Behavior Gary Berg-Cross, Knowledge Strategies Potomac, Maryland

LONG-TERM BEHAVIORAL AND NEUROCHEMICAL EFFECTS OF INTRADENTATE ADMINISTRATION OF COLCHICINE IN RATS

EPA Science Inventory

Previous work has shown that the intradentate administration of colchicine produces time-dependent behavioral and neurochemical changes. eficits in learning and memory and alterations In the signal transduction process for the cholinergic muscarinic receptor have been observed up...

Prior Learning of Relevant Nonaversive Information Is a Boundary Condition for Avoidance Memory Reconsolidation in the Rat Hippocampus.

PubMed

Radiske, Andressa; Gonzalez, Maria Carolina; Conde-Ocazionez, Sergio A; Feitosa, Anatildes; Köhler, Cristiano A; Bevilaqua, Lia R; Cammarota, Martín

2017-10-04

Reactivated memories can be modified during reconsolidation, making this process a potential therapeutic target for posttraumatic stress disorder (PTSD), a mental illness characterized by the recurring avoidance of situations that evoke trauma-related fears. However, avoidance memory reconsolidation depends on a set of still loosely defined boundary conditions, limiting the translational value of basic research. In particular, the involvement of the hippocampus in fear-motivated avoidance memory reconsolidation remains controversial. Combining behavioral and electrophysiological analyses in male Wistar rats, we found that previous learning of relevant nonaversive information is essential to elicit the participation of the hippocampus in avoidance memory reconsolidation, which is associated with an increase in theta- and gamma-oscillation power and cross-frequency coupling in dorsal CA1 during reactivation of the avoidance response. Our results indicate that the hippocampus is involved in memory reconsolidation only when reactivation results in contradictory representations regarding the consequences of avoidance and suggest that robust nesting of hippocampal theta-gamma rhythms at the time of retrieval is a specific reconsolidation marker. SIGNIFICANCE STATEMENT Posttraumatic stress disorder (PTSD) is characterized by maladaptive avoidance responses to stimuli or behaviors that represent or bear resemblance to some aspect of a traumatic experience. Disruption of reconsolidation, the process by which reactivated memories become susceptible to modifications, is a promising approach for treating PTSD patients. However, much of what is known about fear-motivated avoidance memory reconsolidation derives from studies based on fear conditioning instead of avoidance-learning paradigms. Using a step-down inhibitory avoidance task in rats, we found that the hippocampus is involved in memory reconsolidation only when the animals acquired the avoidance response in an environment that they had previously learned as safe and showed that increased theta- and gamma-oscillation coupling during reactivation is an electrophysiological signature of this process. Copyright © 2017 the authors 0270-6474/17/379675-11$15.00/0.

Sleeping brain, learning brain. The role of sleep for memory systems.

PubMed

Peigneux, P; Laureys, S; Delbeuck, X; Maquet, P

2001-12-21

The hypothesis that sleep participates in the consolidation of recent memory traces has been investigated using four main paradigms: (1) effects of post-training sleep deprivation on memory consolidation, (2) effects of learning on post-training sleep, (3) effects of within sleep stimulation on the sleep pattern and on overnight memories, and (4) re-expression of behavior-specific neural patterns during post-training sleep. These studies convincingly support the idea that sleep is deeply involved in memory functions in humans and animals. However, the available data still remain too scarce to confirm or reject unequivocally the recently upheld hypothesis that consolidations of non-declarative and declarative memories are respectively dependent upon REM and NREM sleep processes.

Emotional memory in schizophrenia.

PubMed

Herbener, Ellen S

2008-09-01

Emotional memories play an important role in our day-to-day experience, informing many of our minute-to-minute decisions (eg, where to go for dinner, what are the likely consequences of not attending a meeting), as well as our long-term goal setting. Individuals with schizophrenia appear to be impaired in memory for emotional experiences, particularly over longer delay periods, which may contribute to deficits in goal-related behavior and symptoms of amotivation and anhedonia. This article reviews factors that are known to influence emotional memory in healthy subjects, applies these factors to results from emotional memory studies with individuals with schizophrenia, and then uses extant neurobiological models of emotional memory formation to develop hypotheses about biological processes that might particularly contribute to emotional memory impairment in schizophrenia.

The Effect of Various Strategies on the Acquisition, Retention, and Transfer of a Serial Positioning Task

DTIC Science & Technology

1979-07-01

child development and behavior. N. Y.: Academic Press, 1974. Craik , F. I.M., & Lockhart , R. S. Levels of processing : A framework for memory research...F. I. M. Craik & L. S. Cermak (Eds.), Levels of processing and theories of memory. Hillsdale, N. J.: Erlbaum, 1978. Bruner, J. S. The act of discovery... Lockhart , 1972; Craik & Tulving, 1975). Although the dependent measures differ, the conclusions drawn remain similar. Strategy usage has a facilitatory

Anomalous Fluctuations in Autoregressive Models with Long-Term Memory

NASA Astrophysics Data System (ADS)

Sakaguchi, Hidetsugu; Honjo, Haruo

2015-10-01

An autoregressive model with a power-law type memory kernel is studied as a stochastic process that exhibits a self-affine-fractal-like behavior for a small time scale. We find numerically that the root-mean-square displacement Δ(m) for the time interval m increases with a power law as mα with α < 1/2 for small m but saturates at sufficiently large m. The exponent α changes with the power exponent of the memory kernel.

Epigenetic Regulation of Learning and Memory by Drosophila EHMT/G9a

PubMed Central

Kramer, Jamie M.; Kochinke, Korinna; Oortveld, Merel A. W.; Marks, Hendrik; Kramer, Daniela; de Jong, Eiko K.; Asztalos, Zoltan; Westwood, J. Timothy; Stunnenberg, Hendrik G.; Sokolowski, Marla B.; Keleman, Krystyna; Zhou, Huiqing; van Bokhoven, Hans; Schenck, Annette

2011-01-01

The epigenetic modification of chromatin structure and its effect on complex neuronal processes like learning and memory is an emerging field in neuroscience. However, little is known about the “writers” of the neuronal epigenome and how they lay down the basis for proper cognition. Here, we have dissected the neuronal function of the Drosophila euchromatin histone methyltransferase (EHMT), a member of a conserved protein family that methylates histone 3 at lysine 9 (H3K9). EHMT is widely expressed in the nervous system and other tissues, yet EHMT mutant flies are viable. Neurodevelopmental and behavioral analyses identified EHMT as a regulator of peripheral dendrite development, larval locomotor behavior, non-associative learning, and courtship memory. The requirement for EHMT in memory was mapped to 7B-Gal4 positive cells, which are, in adult brains, predominantly mushroom body neurons. Moreover, memory was restored by EHMT re-expression during adulthood, indicating that cognitive defects are reversible in EHMT mutants. To uncover the underlying molecular mechanisms, we generated genome-wide H3K9 dimethylation profiles by ChIP-seq. Loss of H3K9 dimethylation in EHMT mutants occurs at 5% of the euchromatic genome and is enriched at the 5′ and 3′ ends of distinct classes of genes that control neuronal and behavioral processes that are corrupted in EHMT mutants. Our study identifies Drosophila EHMT as a key regulator of cognition that orchestrates an epigenetic program featuring classic learning and memory genes. Our findings are relevant to the pathophysiological mechanisms underlying Kleefstra Syndrome, a severe form of intellectual disability caused by mutations in human EHMT1, and have potential therapeutic implications. Our work thus provides novel insights into the epigenetic control of cognition in health and disease. PMID:21245904

Dopaminergic and cholinergic modulations of visual-spatial attention and working memory: insights from molecular genetic research and implications for adult cognitive development.

PubMed

Störmer, Viola S; Passow, Susanne; Biesenack, Julia; Li, Shu-Chen

2012-05-01

Attention and working memory are fundamental for selecting and maintaining behaviorally relevant information. Not only do both processes closely intertwine at the cognitive level, but they implicate similar functional brain circuitries, namely the frontoparietal and the frontostriatal networks, which are innervated by cholinergic and dopaminergic pathways. Here we review the literature on cholinergic and dopaminergic modulations of visual-spatial attention and visual working memory processes to gain insights on aging-related changes in these processes. Some extant findings have suggested that the cholinergic system plays a role in the orienting of attention to enable the detection and discrimination of visual information, whereas the dopaminergic system has mainly been associated with working memory processes such as updating and stabilizing representations. However, since visual-spatial attention and working memory processes are not fully dissociable, there is also evidence of interacting cholinergic and dopaminergic modulations of both processes. We further review gene-cognition association studies that have shown that individual differences in visual-spatial attention and visual working memory are associated with acetylcholine- and dopamine-relevant genes. The efficiency of these 2 transmitter systems declines substantially during healthy aging. These declines, in part, contribute to age-related deficits in attention and working memory functions. We report novel data showing an effect of dopamine COMT gene on spatial updating processes in older but not in younger adults, indicating potential magnification of genetic effects in old age.

Multiple neural states of representation in short-term memory? It's a matter of attention.

PubMed

Larocque, Joshua J; Lewis-Peacock, Jarrod A; Postle, Bradley R

2014-01-01

Short-term memory (STM) refers to the capacity-limited retention of information over a brief period of time, and working memory (WM) refers to the manipulation and use of that information to guide behavior. In recent years it has become apparent that STM and WM interact and overlap with other cognitive processes, including attention (the selection of a subset of information for further processing) and long-term memory (LTM-the encoding and retention of an effectively unlimited amount of information for a much longer period of time). Broadly speaking, there have been two classes of memory models: systems models, which posit distinct stores for STM and LTM (Atkinson and Shiffrin, 1968; Baddeley and Hitch, 1974); and state-based models, which posit a common store with different activation states corresponding to STM and LTM (Cowan, 1995; McElree, 1996; Oberauer, 2002). In this paper, we will focus on state-based accounts of STM. First, we will consider several theoretical models that postulate, based on considerable behavioral evidence, that information in STM can exist in multiple representational states. We will then consider how neural data from recent studies of STM can inform and constrain these theoretical models. In the process we will highlight the inferential advantage of multivariate, information-based analyses of neuroimaging data (fMRI and electroencephalography (EEG)) over conventional activation-based analysis approaches (Postle, in press). We will conclude by addressing lingering questions regarding the fractionation of STM, highlighting differences between the attention to information vs. the retention of information during brief memory delays.

Visual Processing during Short-Term Memory Binding in Mild Alzheimer's Disease.

PubMed

Fernández, Gerardo; Orozco, David; Agamennoni, Osvaldo; Schumacher, Marcela; Sañudo, Silvana; Biondi, Juan; Parra, Mario A

2018-01-01

Patients with Alzheimer's disease (AD) typically present with attentional and oculomotor abnormalities that can have an impact on visual processing and associated cognitive functions. Over the last few years, we have witnessed a shift toward the analyses of eye movement behaviors as a means to further our understanding of the pathophysiology of common disorders such as AD. However, little work has been done to unveil the link between eye moment abnormalities and poor performance on cognitive tasks known to be markers for AD patients, such as the short-term memory-binding task. We analyzed eye movement fixation behaviors of thirteen healthy older adults (Controls) and thirteen patients with probable mild AD while they performed the visual short-term memory binding task. The short-term memory binding task asks participants to detect changes across two consecutive arrays of two bicolored object whose features (i.e., colors) have to be remembered separately (i.e., Unbound Colors), or combined within integrated objects (i.e., Bound Colors). Patients with mild AD showed the well-known pattern of selective memory binding impairments. This was accompanied by significant impairments in their eye movements only when they processed Bound Colors. Patients with mild AD remarkably decreased their mean gaze duration during the encoding of color-color bindings. These findings open new windows of research into the pathophysiological mechanisms of memory deficits in AD patients and the link between its phenotypic expressions (i.e., oculomotor and cognitive disorders). We discuss these findings considering current trends regarding clinical assessment, neural correlates, and potential avenues for robust biomarkers.

The impact of multiple memory formation on dendritic complexity in the hippocampus and anterior cingulate cortex assessed at recent and remote time points

PubMed Central

Wartman, Brianne C.; Holahan, Matthew R.

2014-01-01

Consolidation processes, involving synaptic and systems level changes, are suggested to stabilize memories once they are formed. At the synaptic level, dendritic structural changes are associated with long-term memory storage. At the systems level, memory storage dynamics between the hippocampus and anterior cingulate cortex (ACC) may be influenced by the number of sequentially encoded memories. The present experiment utilized Golgi-Cox staining and neuron reconstruction to examine recent and remote structural changes in the hippocampus and ACC following training on three different behavioral procedures. Rats were trained on one hippocampal-dependent task only (a water maze task), two hippocampal-dependent tasks (a water maze task followed by a radial arm maze task), or one hippocampal-dependent and one non-hippocampal-dependent task (a water maze task followed by an operant conditioning task). Rats were euthanized recently or remotely. Brains underwent Golgi-Cox processing and neurons were reconstructed using Neurolucida software (MicroBrightField, Williston, VT, USA). Rats trained on two hippocampal-dependent tasks displayed increased dendritic complexity compared to control rats, in neurons examined in both the ACC and hippocampus at recent and remote time points. Importantly, this behavioral group showed consistent, significant structural differences in the ACC compared to the control group at the recent time point. These findings suggest that taxing the demand placed upon the hippocampus, by training rats on two hippocampal-dependent tasks, engages synaptic and systems consolidation processes in the ACC at an accelerated rate for recent and remote storage of spatial memories. PMID:24795581

Central Ghrelin Resistance Permits the Overconsolidation of Fear Memory.

PubMed

Harmatz, Elia S; Stone, Lauren; Lim, Seh Hong; Lee, Graham; McGrath, Anna; Gisabella, Barbara; Peng, Xiaoyu; Kosoy, Eliza; Yao, Junmei; Liu, Elizabeth; Machado, Nuno J; Weiner, Veronica S; Slocum, Warren; Cunha, Rodrigo A; Goosens, Ki A

2017-06-15

There are many contradictory findings about the role of the hormone ghrelin in aversive processing, with studies suggesting that ghrelin signaling can both inhibit and enhance aversion. Here, we characterize and reconcile the paradoxical role of ghrelin in the acquisition of fearful memories. We used enzyme-linked immunosorbent assay to measure endogenous acyl-ghrelin and corticosterone at time points surrounding auditory fear learning. We used pharmacological (systemic and intra-amygdala) manipulations of ghrelin signaling and examined several aversive and appetitive behaviors. We also used biotin-labeled ghrelin to visualize ghrelin binding sites in coronal brain sections of amygdala. All work was performed in rats. In unstressed rodents, endogenous peripheral acyl-ghrelin robustly inhibits fear memory consolidation through actions in the amygdala and accounts for virtually all interindividual variability in long-term fear memory strength. Higher levels of endogenous ghrelin after fear learning were associated with weaker long-term fear memories, and pharmacological agonism of the ghrelin receptor during the memory consolidation period reduced fear memory strength. These fear-inhibitory effects cannot be explained by changes in appetitive behavior. In contrast, we show that chronic stress, which increases both circulating endogenous acyl-ghrelin and fear memory formation, promotes profound loss of ghrelin binding sites in the amygdala and behavioral insensitivity to ghrelin receptor agonism. These studies provide a new link between stress, a novel type of metabolic resistance, and vulnerability to excessive fear memory formation and reveal that ghrelin can regulate negative emotionality in unstressed animals without altering appetite. Copyright © 2016 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

The cognitive neuroscience of true and false memories.

PubMed

Johnson, Marcia K; Raye, Carol L; Mitchell, Karen J; Ankudowich, Elizabeth

2012-01-01

Of central relevance to the recovered/false memory debate is understanding the factors that cause us to believe that a mental experience is a memory of an actual past experience. According to the source monitoring framework (SMF), memories are attributions that we make about our mental experiences based on their subjective qualities, our prior knowledge and beliefs, our motives and goals, and the social context. From this perspective, we discuss cognitive behavioral studies using both objective (e.g., recognition, source memory) and subjective (e.g., ratings of memory characteristics) measures that provide much information about the encoding, revival and monitoring processes that yield both true and false memories. The chapter also considers how neuroimaging findings, especially from functional magnetic resonance imaging studies, are contributing to our understanding of the relation between memory and reality.

A unique memory process modulated by emotion underpins successful odor recognition and episodic retrieval in humans

PubMed Central

Saive, Anne-Lise; Royet, Jean-Pierre; Ravel, Nadine; Thévenet, Marc; Garcia, Samuel; Plailly, Jane

2014-01-01

We behaviorally explore the link between olfaction, emotion and memory by testing the hypothesis that the emotion carried by odors facilitates the memory of specific unique events. To investigate this idea, we used a novel behavioral approach inspired by a paradigm developed by our team to study episodic memory in a controlled and as ecological as possible way in humans. The participants freely explored three unique and rich laboratory episodes; each episode consisted of three unfamiliar odors (What) positioned at three specific locations (Where) within a visual context (Which context). During the retrieval test, which occurred 24–72 h after the encoding, odors were used to trigger the retrieval of the complex episodes. The participants were proficient in recognizing the target odors among distractors and retrieving the visuospatial context in which they were encountered. The episodic nature of the task generated high and stable memory performances, which were accompanied by faster responses and slower and deeper breathing. Successful odor recognition and episodic memory were not related to differences in odor investigation at encoding. However, memory performances were influenced by the emotional content of the odors, regardless of odor valence, with both pleasant and unpleasant odors generating higher recognition and episodic retrieval than neutral odors. Finally, the present study also suggested that when the binding between the odors and the spatio-contextual features of the episode was successful, the odor recognition and the episodic retrieval collapsed into a unique memory process that began as soon as the participants smelled the odors. PMID:24936176

The removal of information from working memory.

PubMed

Lewis-Peacock, Jarrod A; Kessler, Yoav; Oberauer, Klaus

2018-05-09

What happens to goal-relevant information in working memory after it is no longer needed? Here, we review evidence for a selective removal process that operates on outdated information to limit working memory load and hence facilitates the maintenance of goal-relevant information. Removal alters the representations of irrelevant content so as to reduce access to it, thereby improving access to the remaining relevant content and also facilitating the encoding of new information. Both behavioral and neural evidence support the existence of a removal process that is separate from forgetting due to decay or interference. We discuss the potential mechanisms involved in removal and characterize the time course and duration of the process. In doing so, we propose the existence of two forms of removal: one is temporary, and reversible, which modifies working memory content without impacting content-to-context bindings, and another is permanent, which unbinds the content from its context in working memory (without necessarily impacting long-term forgetting). Finally, we discuss limitations on removal and prescribe conditions for evaluating evidence for or against this process. © 2018 New York Academy of Sciences.

Histone lysine methylation: critical regulator of memory and behavior.

PubMed

Jarome, Timothy J; Lubin, Farah D

2013-01-01

Histone lysine methylation is a well-established transcriptional mechanism for the regulation of gene expression changes in eukaryotic cells and is now believed to function in neurons of the central nervous system to mediate the process of memory formation and behavior. In mature neurons, methylation of histone proteins can serve to both activate and repress gene transcription. This is in stark contrast to other epigenetic modifications, including histone acetylation and DNA methylation, which have largely been associated with one transcriptional state in the brain. In this review, we discuss the evidence for histone methylation mechanisms in the coordination of complex cognitive processes such as long-term memory formation and storage. In addition, we address the current literature highlighting the role of histone methylation in intellectual disability, addiction, schizophrenia, autism, depression, and neurodegeneration. Further, we discuss histone methylation within the context of other epigenetic modifications and the potential advantages of exploring this newly identified mechanism of cognition, emphasizing the possibility that this molecular process may provide an alternative locus for intervention in long-term psychopathologies that cannot be clearly linked to genes or environment alone.

A phosphodiesterase 4-controlled switch between memory extinction and strengthening in the hippocampus

PubMed Central

Roesler, Rafael; Reolon, Gustavo K.; Maurmann, Natasha; Schwartsmann, Gilberto; Schröder, Nadja; Amaral, Olavo B.; Valvassori, Samira; Quevedo, João

2014-01-01

Established fear-related memories can undergo phenomena such as extinction or reconsolidation when recalled. Extinction probably involves the creation of a new, competing memory trace that decreases fear expression, whereas reconsolidation can mediate memory maintenance, updating, or strengthening. The factors determining whether retrieval will initiate extinction, reconsolidation, or neither of these two processes include training intensity, duration of the retrieval session, and age of the memory. However, previous studies have not shown that the same behavioral protocol can be used to induce either extinction or reconsolidation and strengthening, depending on the pharmacological intervention used. Here we show that, within an experiment that leads to extinction in control rats, memory can be strengthened if rolipram, a selective inhibitor of phosphodiesterase type 4 (PDE4), is administered into the dorsal hippocampus immediately after retrieval. The memory-enhancing effect of rolipram lasted for at least 1 week, was blocked by the protein synthesis inhibitor anisomycin, and did not occur when drug administration was not paired with retrieval. These findings indicate that the behavioral outcome of memory retrieval can be pharmacologically switched from extinction to strengthening. The cAMP/protein kinase A (PKA) signaling pathway might be a crucial mechanism determining the fate of memories after recall. PMID:24672454

Short-term plasticity as a neural mechanism supporting memory and attentional functions.

PubMed

Jääskeläinen, Iiro P; Ahveninen, Jyrki; Andermann, Mark L; Belliveau, John W; Raij, Tommi; Sams, Mikko

2011-11-08

Based on behavioral studies, several relatively distinct perceptual and cognitive functions have been defined in cognitive psychology such as sensory memory, short-term memory, and selective attention. Here, we review evidence suggesting that some of these functions may be supported by shared underlying neuronal mechanisms. Specifically, we present, based on an integrative review of the literature, a hypothetical model wherein short-term plasticity, in the form of transient center-excitatory and surround-inhibitory modulations, constitutes a generic processing principle that supports sensory memory, short-term memory, involuntary attention, selective attention, and perceptual learning. In our model, the size and complexity of receptive fields/level of abstraction of neural representations, as well as the length of temporal receptive windows, increases as one steps up the cortical hierarchy. Consequently, the type of input (bottom-up vs. top down) and the level of cortical hierarchy that the inputs target, determine whether short-term plasticity supports purely sensory vs. semantic short-term memory or attentional functions. Furthermore, we suggest that rather than discrete memory systems, there are continuums of memory representations from short-lived sensory ones to more abstract longer-duration representations, such as those tapped by behavioral studies of short-term memory. Copyright © 2011 Elsevier B.V. All rights reserved.

Audiovisual integration facilitates monkeys' short-term memory.

PubMed

Bigelow, James; Poremba, Amy

2016-07-01

Many human behaviors are known to benefit from audiovisual integration, including language and communication, recognizing individuals, social decision making, and memory. Exceptionally little is known about the contributions of audiovisual integration to behavior in other primates. The current experiment investigated whether short-term memory in nonhuman primates is facilitated by the audiovisual presentation format. Three macaque monkeys that had previously learned an auditory delayed matching-to-sample (DMS) task were trained to perform a similar visual task, after which they were tested with a concurrent audiovisual DMS task with equal proportions of auditory, visual, and audiovisual trials. Parallel to outcomes in human studies, accuracy was higher and response times were faster on audiovisual trials than either unisensory trial type. Unexpectedly, two subjects exhibited superior unimodal performance on auditory trials, a finding that contrasts with previous studies, but likely reflects their training history. Our results provide the first demonstration of a bimodal memory advantage in nonhuman primates, lending further validation to their use as a model for understanding audiovisual integration and memory processing in humans.

Circadian Rhythms in Fear Conditioning: An Overview of Behavioral, Brain System, and Molecular Interactions

PubMed Central

Stork, Oliver

2017-01-01

The formation of fear memories is a powerful and highly evolutionary conserved mechanism that serves the behavioral adaptation to environmental threats. Accordingly, classical fear conditioning paradigms have been employed to investigate fundamental molecular processes of memory formation. Evidence suggests that a circadian regulation mechanism allows for a timestamping of such fear memories and controlling memory salience during both their acquisition and their modification after retrieval. These mechanisms include an expression of molecular clocks in neurons of the amygdala, hippocampus, and medial prefrontal cortex and their tight interaction with the intracellular signaling pathways that mediate neural plasticity and information storage. The cellular activities are coordinated across different brain regions and neural circuits through the release of glucocorticoids and neuromodulators such as acetylcholine, which integrate circadian and memory-related activation. Disturbance of this interplay by circadian phase shifts or traumatic experience appears to be an important factor in the development of stress-related psychopathology, considering these circadian components are of critical importance for optimizing therapeutic approaches to these disorders. PMID:28698810

Many Roads Lead to Recognition: Electrophysiological Correlates of Familiarity Derived from Short-Term Masked Repetition Priming

ERIC Educational Resources Information Center

Lucas, Heather D.; Taylor, Jason R.; Henson, Richard N.; Paller, Ken A.

2012-01-01

The neural mechanisms that underlie familiarity memory have been extensively investigated, but a consensus understanding remains elusive. Behavioral evidence suggests that familiarity sometimes shares sources with instances of implicit memory known as priming, in that the same increases in processing fluency that give rise to priming can engender…

Dopaminergic and Cholinergic Modulations of Visual-Spatial Attention and Working Memory: Insights from Molecular Genetic Research and Implications for Adult Cognitive Development

ERIC Educational Resources Information Center

Stormer, Viola S.; Passow, Susanne; Biesenack, Julia; Li, Shu-Chen

2012-01-01

Attention and working memory are fundamental for selecting and maintaining behaviorally relevant information. Not only do both processes closely intertwine at the cognitive level, but they implicate similar functional brain circuitries, namely the frontoparietal and the frontostriatal networks, which are innervated by cholinergic and dopaminergic…

Exploring Expressive Vocabulary Variability in Two-Year-Olds: The Role of Working Memory

ERIC Educational Resources Information Center

Newbury, Jayne; Klee, Thomas; Stokes, Stephanie F.; Moran, Catherine

2015-01-01

Purpose: This study explored whether measures of working memory ability contribute to the wide variation in 2-year-olds' expressive vocabulary skills. Method: Seventy-nine children (aged 24-30 months) were assessed by using standardized tests of vocabulary and visual cognition, a processing speed measure, and behavioral measures of verbal working…

The Effect of Non-Visual Working Memory Load on Top-Down Modulation of Visual Processing

ERIC Educational Resources Information Center

Rissman, Jesse; Gazzaley, Adam; D'Esposito, Mark

2009-01-01

While a core function of the working memory (WM) system is the active maintenance of behaviorally relevant sensory representations, it is also critical that distracting stimuli are appropriately ignored. We used functional magnetic resonance imaging to examine the role of domain-general WM resources in the top-down attentional modulation of…

Adolescents at Risk for Drug Abuse: A 3-Year Dual Process Analysis

PubMed Central

Ames, S.L.; Xie, B.; Shono, Y.; Stacy, A.W.

2016-01-01

Aims To test longitudinal additive and synergistic dual process models in youth at documented risk for drug use. The specific dual process approach examined suggests that engaging in drug use behaviors results from a dynamic interplay between automatically-activated associative memory processes and executive reflective/control processes. Design This 3-year, three-wave population-based prospective study used mobile computer-based assessments. Setting Self-directed computer assessments were completed in school settings in the Los Angeles metropolitan area, California, USA. Participants 725 at-risk adolescents (44% female) in continuation high schools were recruited during 9th grade (age at recruitment, 14 to 16). Measurements Key outcome measures included past year alcohol, marijuana and cigarette use at each assessment. Predictors included working memory capacity (WMC), associative memory, the interaction term WMC by associative memory, sex, age, ethnicity, and acculturation. Findings A significant cross-sectional interaction revealed tobacco-relevant associations were weaker predictors of cigarette use among males with higher WMC than among those with lower WMC (p<0.004). Alternatively, drug-relevant associations were stronger predictors of past year alcohol (p<0.001) and marijuana use (p=0.02) among females with higher WMC than among those with lower WMC. Longitudinal analyses revealed no significant interactions after adjusting for predictive effects of previous drug use. With respect to WMC, females with higher WMC were less likely to use marijuana at two-year follow-up (p=0.03). First-order effects of drug-related associations prospectively predicted greater alcohol and marijuana use in males at one and two-year follow up (p≤0.03), and greater past year alcohol and marijuana use in females at one-year follow up (p≤0.03). Conclusions Drug-relevant memory associations play a key role in drug use behavior in at-risk youth. PMID:28010052

Potential High-Temperature Shape-Memory Alloys Identified in the Ti(Ni,Pt) System

NASA Technical Reports Server (NTRS)

Noebe, Ronald D.; Biles, Tiffany A.; Garg, Anita; Nathal, Michael V.

2004-01-01

"Shape memory" is a unique property of certain alloys that, when deformed (within certain strain limits) at low temperatures, will remember and recover to their original predeformed shape upon heating. It occurs when an alloy is deformed in the low-temperature martensitic phase and is then heated above its transformation temperature back to an austenitic state. As the material passes through this solid-state phase transformation on heating, it also recovers its original shape. This behavior is widely exploited, near room temperature, in commercially available NiTi alloys for connectors, couplings, valves, actuators, stents, and other medical and dental devices. In addition, there are limitless applications in the aerospace, automotive, chemical processing, and many other industries for materials that exhibit this type of shape-memory behavior at higher temperatures. But for high temperatures, there are currently no commercial shape-memory alloys. Although there are significant challenges to the development of high-temperature shape-memory alloys, at the NASA Glenn Research Center we have identified a series of alloy compositions in the Ti-Ni-Pt system that show great promise as potential high-temperature shape-memory materials.

Zinc supplementation in rats impairs hippocampal-dependent memory consolidation and dampens post-traumatic recollection of stressful event.

PubMed

Contestabile, Antonio; Peña-Altamira, Emiliano; Virgili, Marco; Monti, Barbara

2016-06-01

Zinc is a trace element important for synaptic plasticity, learning and memory. Zinc deficiency, both during pregnancy and after birth, impairs cognitive performance and, in addition to memory deficits, also results in alterations of attention, activity, neuropsychological behavior and motor development. The effects of zinc supplementation on cognition, particularly in the adult, are less clear. We demonstrate here in adult rats, that 4 week-long zinc supplementation given by drinking water, and approximately doubling normal daily intake, strongly impairs consolidation of hippocampal-dependent memory, tested through contextual fear conditioning and inhibitory avoidance. Furthermore, the same treatment started after memory consolidation of training for the same behavioral tests, substantially dampens the recall of the stressful event occurred 4 weeks before. A molecular correlate of the amnesic effect of zinc supplementation is represented by a dysregulated function of GSK-3ß in the hippocampus, a kinase that participates in memory processes. The possible relevance of these data for humans, in particular regarding post-traumatic stress disorders, is discussed in view of future investigation. Copyright © 2016 Elsevier B.V. and ECNP. All rights reserved.

The Ease of Language Understanding (ELU) model: theoretical, empirical, and clinical advances

PubMed Central

Rönnberg, Jerker; Lunner, Thomas; Zekveld, Adriana; Sörqvist, Patrik; Danielsson, Henrik; Lyxell, Björn; Dahlström, Örjan; Signoret, Carine; Stenfelt, Stefan; Pichora-Fuller, M. Kathleen; Rudner, Mary

2013-01-01

Working memory is important for online language processing during conversation. We use it to maintain relevant information, to inhibit or ignore irrelevant information, and to attend to conversation selectively. Working memory helps us to keep track of and actively participate in conversation, including taking turns and following the gist. This paper examines the Ease of Language Understanding model (i.e., the ELU model, Rönnberg, 2003; Rönnberg et al., 2008) in light of new behavioral and neural findings concerning the role of working memory capacity (WMC) in uni-modal and bimodal language processing. The new ELU model is a meaning prediction system that depends on phonological and semantic interactions in rapid implicit and slower explicit processing mechanisms that both depend on WMC albeit in different ways. It is based on findings that address the relationship between WMC and (a) early attention processes in listening to speech, (b) signal processing in hearing aids and its effects on short-term memory, (c) inhibition of speech maskers and its effect on episodic long-term memory, (d) the effects of hearing impairment on episodic and semantic long-term memory, and finally, (e) listening effort. New predictions and clinical implications are outlined. Comparisons with other WMC and speech perception models are made. PMID:23874273

Extinction and recovery of an avoidance memory impaired by scopolamine.

PubMed

Navarro, N M; Krawczyk, M C; Boccia, M M; Blake, M G

2017-03-15

Pre-training administration of scopolamine (SCP) resembles situations of cholinergic dysfunction, leading to memory impairment of mice trained in an inhibitory avoidance task. We suggest here that SCP does not impair memory formation, but acquisition is affected in a way that reduces the strength of the stored memory, thus making this memory less able to control behavior when tested. Hence, a memory trace is stored, but is poorly expressed during the test. Although weakly expressed, this memory shows extinction during successive tests, and can be strengthened by using a reminder. Our results indicate that memories stored under cholinergic dysfunction conditions seem absent or lost, but are in fact present and experience common memory processes, such as extinction, and could be even recovered by using appropriate protocols. Copyright © 2017 Elsevier Inc. All rights reserved.

Tuning the Electrical Memory Behavior from Nonvolatile to Volatile in Functional Copolyimides Bearing Varied Fluorene and Pyrene Moieties

NASA Astrophysics Data System (ADS)

Jia, Nanfang; Qi, Shengli; Tian, Guofeng; Wang, Xiaodong; Wu, Dezhen

2017-04-01

For producing polymer based electronics with good memory behavior, a series of functional copolyimides were designed and synthesized in this work by copolymerizing 3,3',4,4'-diphenylsulfonetetracarboxylic dianhydride (DSDA) with (9,9'-bis(4-aminophenyl)fluorene) (BAPF) and N, N-bis(4-aminophenyl) aminopyrene (DAPAP) diamines. The synthesized copolyimides DSDA/(DAPAP/BAPF) were denoted as coPI-DAPAP x ( x = 100, 50, 20, 10, 5, 1, 0), where x% represents the molar fraction of the DAPAP unit in the diamines. Characterization results indicate that the coPI-DAPAP x exhibits tunable electrical switching behaviors from write once read many times (WORM, nonvolatile, coPI-DAPAP100, coPI-DAPAP50, coPI-DAPAP20, coPI-DAPAP10) to the static random access memory (SRAM, volatile, coPI-DAPAP5, coPI-DAPAP1) with the variation of the DAPAP content. Optical and electrochemical characterization show gradually decreasing highest occupied molecular orbital levels and enlarged energy gap with the decrease of the DAPAP moiety, suggesting decreasing charge-transfer effect in the copolyimides, which can account for the observed WORM-SRAM memory conversion. Meanwhile, the charge transfer process was elucidated by quantum chemical calculation at B3LYP/6-31G(d) theory level. This work shows the effect of electron donor content on the memory behavior of polymer electronic materials.

Memory Erasure Experiments Indicate a Critical Role of CaMKII in Memory Storage.

PubMed

Rossetti, Tom; Banerjee, Somdeb; Kim, Chris; Leubner, Megan; Lamar, Casey; Gupta, Pooja; Lee, Bomsol; Neve, Rachael; Lisman, John

2017-09-27

The abundant synaptic protein CaMKII is necessary for long-term potentiation (LTP) and memory. However, whether CaMKII is required only during initial processes or whether it also mediates memory storage remains unclear. The most direct test of a storage role is the erasure test. In this test, a putative memory molecule is inhibited after learning. The key prediction is that this should produce persistent memory erasure even after the inhibitory agent is removed. We conducted this test using transient viral (HSV) expression of dominant-negative CaMKII-alpha (K42M) in the hippocampus. This produced persistent erasure of conditioned place avoidance. As an additional test, we found that expression of activated CaMKII (T286D/T305A/T306A) impaired place avoidance, a result not expected if a process other than CaMKII stores memory. Our behavioral results, taken together with prior experiments on LTP, strongly support a critical role of CaMKII in LTP maintenance and memory storage. Copyright © 2017 Elsevier Inc. All rights reserved.

Infant information processing and family history of specific language impairment: converging evidence for RAP deficits from two paradigms

PubMed Central

Choudhury, Naseem; Leppanen, Paavo H.T.; Leevers, Hilary J.; Benasich, April A.

2007-01-01

An infant’s ability to process auditory signals presented in rapid succession (i.e. rapid auditory processing abilities [RAP]) has been shown to predict differences in language outcomes in toddlers and preschool children. Early deficits in RAP abilities may serve as a behavioral marker for language-based learning disabilities. The purpose of this study is to determine if performance on infant information processing measures designed to tap RAP and global processing skills differ as a function of family history of specific language impairment (SLI) and/or the particular demand characteristics of the paradigm used. Seventeen 6- to 9-month-old infants from families with a history of specific language impairment (FH+) and 29 control infants (FH−) participated in this study. Infants’ performance on two different RAP paradigms (head-turn procedure [HT] and auditory-visual habituation/recognition memory [AVH/RM]) and on a global processing task (visual habituation/recognition memory [VH/RM]) was assessed at 6 and 9 months. Toddler language and cognitive skills were evaluated at 12 and 16 months. A number of significant group differences were seen: FH+ infants showed significantly poorer discrimination of fast rate stimuli on both RAP tasks, took longer to habituate on both habituation/recognition memory measures, and had lower novelty preference scores on the visual habituation/recognition memory task. Infants’ performance on the two RAP measures provided independent but converging contributions to outcome. Thus, different mechanisms appear to underlie performance on operantly conditioned tasks as compared to habituation/recognition memory paradigms. Further, infant RAP processing abilities predicted to 12- and 16-month language scores above and beyond family history of SLI. The results of this study provide additional support for the validity of infant RAP abilities as a behavioral marker for later language outcome. Finally, this is the first study to use a battery of infant tasks to demonstrate multi-modal processing deficits in infants at risk for SLI. PMID:17286846

Digital memory encoding in Chinese dyscalculia: An event-related potential study.

PubMed

Wang, Enguo; Qin, Shutao; Chang, MengYan; Zhu, Xiangru

2014-10-22

This study reports the neurophysiological and behavioral correlates of digital memory encoding features in Chinese individuals with and without dyscalculia. Eighteen children with dyscalculia (ages 11.5-13.5) and 18 matched controls were tested, and their event-related potentials (ERPs) were digitally recorded simultaneously with behavioral measures. The results showed that both groups had a significant Dm effect, and this effect was greater in the control group. In the 300-400-ms, 400-500-ms, and 600-700-ms processing stages, both groups showed significant differences of digital memory encoding in the frontal, central, and parietal regions. In the 500-600-ms period, the Dm effect in the control group was significantly greater than that in the dyscalculia group only in the parietal region. These results suggest that individuals with dyscalculia exhibit impaired digital memory encoding and deficits in psychological resource allocation. Copyright © 2014 Elsevier Ltd. All rights reserved.

Pathways to Third-Grade Calculation Versus Word-Reading Competence: Are They More Alike or Different?

PubMed

Fuchs, Lynn S; Geary, David C; Fuchs, Douglas; Compton, Donald L; Hamlett, Carol L

2016-01-01

Children (n = 747; 6.5 years) were assessed on domain-general processes and mathematics and reading-related competencies (start of first grade), addition retrieval (end of second grade), and calculations and word reading (end of third grade). Attentive behavior, reasoning, visuospatial memory, and rapid automatized naming (RAN) indirectly contributed to both outcomes, via retrieval. However, there was no overlap in domain-general direct effects on calculations (attentive behavior, reasoning, working memory) versus word reading (language, phonological memory, RAN). Results suggest ease of forming associative relations and abilities engaged during the formation of these long-term memories are common to both outcomes and can be indexed by addition-fact retrieval, but further growth in calculations and word reading is driven by different constellations of domain-general abilities. © 2015 The Authors. Child Development © 2015 Society for Research in Child Development, Inc.

Absence of verbal recall or memory for symptom acquisition in fear and trauma exposure: a conceptual case for fear conditioning and learned nonuse in assessment and treatment.

PubMed

Seifert, A Ronald

2012-01-01

Absence of memory or verbal recall for symptom acquisition in fear and trauma exposure, as well as absence of successful coping behavior for life events, is associated with a number of diagnoses, including traumatic brain injury, posttraumatic stress disorder, pain, and anxiety. The difficulty with diagnosis and treatment planning based on the absence of recall, memory, and successful coping behavior is threefold: (1) these assessments do not distinguish between disruption of behavior and lack of capacity, (2) the absence of verbal recall and memory complicates cognitive-based treatment, and (3) a confounding issue is the same absent behavior can be observed at different times and contexts. While memory of the specific details of the initial traumatic event(s) may not be available to verbal report, the existence of time- and context-dependent relationships for the initial as well as subsequent experiences is arguable. The absence of memory or lack of verbal recall does not rule out measurable physiological bodily responses for the initial trauma(s), nor does it help to establish the effects of subsequent experiences for symptom expression. Also, the absence of memory must include the prospect of fear-based learning that does not require or involve the cortex. It is posited that the literatures of fear conditioning and learned nonuse provide complementary illustrations of how the time and context of the initial trauma(s) and subsequent experiences affect behavior, which is not dependent on the effected individual being able to provide a memory-based verbal report. The replicated clinical application demonstrates that, without scientific demonstration, neither neuroanatomy nor verbal report can be assumed sufficient to predict overt behavior or physiologic responses. For example, while commonly assumed to be predictively so, autonomic nervous system innervation is insufficient to define the unique stimulus- and context-dependent physiological responses of an individual. By recording simultaneous physiological responses to the controlled presentation of a context-dependent stimulus, the unique relationships of physiology and overt behaviors for the individual can be demonstrated. Using this process also allows more complex virtual reality or other in vivo stimulus assessments to be incorporated for the development of individually tailored assessments and therapeutic plans. Thus, with or without memory or verbal recall, the use of multiple time- and context-specific simultaneous physiological measures and overt behavior can guide clinical effort as well as serve to objectively assess the ongoing treatment and its outcome.

Exposure to a fearful context during periods of memory plasticity impairs extinction via hyperactivation of frontal-amygdalar circuits

PubMed Central

Stafford, James M.; Maughan, DeeAnna K.; Ilioi, Elena C.; Lattal, K. Matthew

2013-01-01

An issue of increasing theoretical and translational importance is to understand the conditions under which learned fear can be suppressed, or even eliminated. Basic research has pointed to extinction, in which an organism is exposed to a fearful stimulus (such as a context) in the absence of an expected aversive outcome (such as a shock). This extinction process results in the suppression of fear responses, but is generally thought to leave the original fearful memory intact. Here, we investigate the effects of extinction during periods of memory lability on behavioral responses and on expression of the immediate–early gene c-Fos within fear conditioning and extinction circuits. Our results show that long-term extinction is impaired when it occurs during time periods during which the memory should be most vulnerable to disruption (soon after conditioning or retrieval). These behavioral effects are correlated with hyperactivation of medial prefrontal cortex and amygdala subregions associated with fear expression rather than fear extinction. These findings demonstrate that behavioral experiences during periods of heightened fear prevent extinction and prolong the conditioned fear response. PMID:23422280

Remote semantic memory for public figures in HIV infection, alcoholism, and their comorbidity.

PubMed

Fama, Rosemary; Rosenbloom, Margaret J; Sassoon, Stephanie A; Thompson, Megan A; Pfefferbaum, Adolf; Sullivan, Edith V

2011-02-01

Impairments in component processes of working and episodic memory mark both HIV infection and chronic alcoholism, with compounded deficits often observed in individuals comorbid for these conditions. Remote semantic memory processes, however, have only seldom been studied in these diagnostic groups. Examination of remote semantic memory could provide insight into the underlying processes associated with storage and retrieval of learned information over extended time periods while elucidating spared and impaired cognitive functions in these clinical groups. We examined component processes of remote semantic memory in HIV infection and chronic alcoholism in 4 subject groups (HIV, ALC, HIV + ALC, and age-matched healthy adults) using a modified version of the Presidents Test. Free recall, recognition, and sequencing of presidential candidates and election dates were assessed. In addition, component processes of working, episodic, and semantic memory were assessed with ancillary cognitive tests. The comorbid group (HIV + ALC) was significantly impaired on sequencing of remote semantic information compared with age-matched healthy adults. Free recall of remote semantic information was also modestly impaired in the HIV + ALC group, but normal performance for recognition of this information was observed. Few differences were observed between the single diagnosis groups (HIV, ALC) and healthy adults, although examination of the component processes underlying remote semantic memory scores elicited differences between the HIV and ALC groups. Selective remote memory processes were related to lifetime alcohol consumption in the ALC group and to viral load and depression level in the HIV group. Hepatitis C diagnosis was associated with lower remote semantic memory scores in all 3 clinical groups. Education level did not account for group differences reported. This study provides behavioral support for the existence of adverse effects associated with the comorbidity of HIV infection and chronic alcoholism on selective component processes of memory function, with untoward effects exacerbated by Hepatitis C infection. The pattern of remote semantic memory function in HIV + ALC is consistent with those observed in neurological conditions primarily affecting frontostriatal pathways and suggests that remote memory dysfunction in HIV + ALC may be a result of impaired retrieval processes rather than loss of remote semantic information per se. Copyright © 2010 by the Research Society on Alcoholism.

Individual differences in working memory capacity and dual-process theories of the mind.

PubMed

Barrett, Lisa Feldman; Tugade, Michele M; Engle, Randall W

2004-07-01

Dual-process theories of the mind are ubiquitous in psychology. A central principle of these theories is that behavior is determined by the interplay of automatic and controlled processing. In this article, the authors examine individual differences in the capacity to control attention as a major contributor to differences in working memory capacity (WMC). The authors discuss the enormous implications of this individual difference for a host of dual-process theories in social, personality, cognitive, and clinical psychology. In addition, the authors propose several new areas of investigation that derive directly from applying the concept of WMC to dual-process theories of the mind.

Individual Differences in Working Memory Capacity and Dual-Process Theories of the Mind

PubMed Central

Barrett, Lisa Feldman; Tugade, Michele M.; Engle, Randall W.

2005-01-01

Dual-process theories of the mind are ubiquitous in psychology. A central principle of these theories is that behavior is determined by the interplay of automatic and controlled processing. In this article, the authors examine individual differences in the capacity to control attention as a major contributor to differences in working memory capacity (WMC). The authors discuss the enormous implications of this individual difference for a host of dual-process theories in social, personality, cognitive, and clinical psychology. In addition, the authors propose several new areas of investigation that derive directly from applying the concept of WMC to dual-process theories of the mind. PMID:15250813

Hemispheric asymmetry in new neurons in adulthood is associated with vocal learning and auditory memory.

PubMed

Tsoi, Shuk C; Aiya, Utsav V; Wasner, Kobi D; Phan, Mimi L; Pytte, Carolyn L; Vicario, David S

2014-01-01

Many brain regions exhibit lateral differences in structure and function, and also incorporate new neurons in adulthood, thought to function in learning and in the formation of new memories. However, the contribution of new neurons to hemispheric differences in processing is unknown. The present study combines cellular, behavioral, and physiological methods to address whether 1) new neuron incorporation differs between the brain hemispheres, and 2) the degree to which hemispheric lateralization of new neurons correlates with behavioral and physiological measures of learning and memory. The songbird provides a model system for assessing the contribution of new neurons to hemispheric specialization because songbird brain areas for vocal processing are functionally lateralized and receive a continuous influx of new neurons in adulthood. In adult male zebra finches, we quantified new neurons in the caudomedial nidopallium (NCM), a forebrain area involved in discrimination and memory for the complex vocalizations of individual conspecifics. We assessed song learning and recorded neural responses to song in NCM. We found significantly more new neurons labeled in left than in right NCM; moreover, the degree of asymmetry in new neuron numbers was correlated with the quality of song learning and strength of neuronal memory for recently heard songs. In birds with experimentally impaired song quality, the hemispheric difference in new neurons was diminished. These results suggest that new neurons may contribute to an allocation of function between the hemispheres that underlies the learning and processing of complex signals.

Hemispheric Asymmetry in New Neurons in Adulthood Is Associated with Vocal Learning and Auditory Memory

PubMed Central

Wasner, Kobi D.; Phan, Mimi L.; Pytte, Carolyn L.; Vicario, David S.

2014-01-01

Many brain regions exhibit lateral differences in structure and function, and also incorporate new neurons in adulthood, thought to function in learning and in the formation of new memories. However, the contribution of new neurons to hemispheric differences in processing is unknown. The present study combines cellular, behavioral, and physiological methods to address whether 1) new neuron incorporation differs between the brain hemispheres, and 2) the degree to which hemispheric lateralization of new neurons correlates with behavioral and physiological measures of learning and memory. The songbird provides a model system for assessing the contribution of new neurons to hemispheric specialization because songbird brain areas for vocal processing are functionally lateralized and receive a continuous influx of new neurons in adulthood. In adult male zebra finches, we quantified new neurons in the caudomedial nidopallium (NCM), a forebrain area involved in discrimination and memory for the complex vocalizations of individual conspecifics. We assessed song learning and recorded neural responses to song in NCM. We found significantly more new neurons labeled in left than in right NCM; moreover, the degree of asymmetry in new neuron numbers was correlated with the quality of song learning and strength of neuronal memory for recently heard songs. In birds with experimentally impaired song quality, the hemispheric difference in new neurons was diminished. These results suggest that new neurons may contribute to an allocation of function between the hemispheres that underlies the learning and processing of complex signals. PMID:25251077

Cognitive Load Does Not Affect the Behavioral and Cognitive Foundations of Social Cooperation.

PubMed

Mieth, Laura; Bell, Raoul; Buchner, Axel

2016-01-01

The present study serves to test whether the cognitive mechanisms underlying social cooperation are affected by cognitive load. Participants interacted with trustworthy-looking and untrustworthy-looking partners in a sequential Prisoner's Dilemma Game. Facial trustworthiness was manipulated to stimulate expectations about the future behavior of the partners which were either violated or confirmed by the partners' cheating or cooperation during the game. In a source memory test, participants were required to recognize the partners and to classify them as cheaters or cooperators. A multinomial model was used to disentangle item memory, source memory and guessing processes. We found an expectancy-congruent bias toward guessing that trustworthy-looking partners were more likely to be associated with cooperation than untrustworthy-looking partners. Source memory was enhanced for cheating that violated the participants' positive expectations about trustworthy-looking partners. We were interested in whether or not this expectancy-violation effect-that helps to revise unjustified expectations about trustworthy-looking partners-depends on cognitive load induced via a secondary continuous reaction time task. Although this secondary task interfered with working memory processes in a validation study, both the expectancy-congruent guessing bias as well as the expectancy-violation effect were obtained with and without cognitive load. These findings support the hypothesis that the expectancy-violation effect is due to a simple mechanism that does not rely on demanding elaborative processes. We conclude that most cognitive mechanisms underlying social cooperation presumably operate automatically so that they remain unaffected by cognitive load.

Cognitive Load Does Not Affect the Behavioral and Cognitive Foundations of Social Cooperation

PubMed Central

Mieth, Laura; Bell, Raoul; Buchner, Axel

2016-01-01

The present study serves to test whether the cognitive mechanisms underlying social cooperation are affected by cognitive load. Participants interacted with trustworthy-looking and untrustworthy-looking partners in a sequential Prisoner’s Dilemma Game. Facial trustworthiness was manipulated to stimulate expectations about the future behavior of the partners which were either violated or confirmed by the partners’ cheating or cooperation during the game. In a source memory test, participants were required to recognize the partners and to classify them as cheaters or cooperators. A multinomial model was used to disentangle item memory, source memory and guessing processes. We found an expectancy-congruent bias toward guessing that trustworthy-looking partners were more likely to be associated with cooperation than untrustworthy-looking partners. Source memory was enhanced for cheating that violated the participants’ positive expectations about trustworthy-looking partners. We were interested in whether or not this expectancy-violation effect—that helps to revise unjustified expectations about trustworthy-looking partners—depends on cognitive load induced via a secondary continuous reaction time task. Although this secondary task interfered with working memory processes in a validation study, both the expectancy-congruent guessing bias as well as the expectancy-violation effect were obtained with and without cognitive load. These findings support the hypothesis that the expectancy-violation effect is due to a simple mechanism that does not rely on demanding elaborative processes. We conclude that most cognitive mechanisms underlying social cooperation presumably operate automatically so that they remain unaffected by cognitive load. PMID:27630597

Experimentally modeling stochastic processes with less memory by the use of a quantum processor

PubMed Central

Palsson, Matthew S.; Gu, Mile; Ho, Joseph; Wiseman, Howard M.; Pryde, Geoff J.

2017-01-01

Computer simulation of observable phenomena is an indispensable tool for engineering new technology, understanding the natural world, and studying human society. However, the most interesting systems are often so complex that simulating their future behavior demands storing immense amounts of information regarding how they have behaved in the past. For increasingly complex systems, simulation becomes increasingly difficult and is ultimately constrained by resources such as computer memory. Recent theoretical work shows that quantum theory can reduce this memory requirement beyond ultimate classical limits, as measured by a process’ statistical complexity, C. We experimentally demonstrate this quantum advantage in simulating stochastic processes. Our quantum implementation observes a memory requirement of Cq = 0.05 ± 0.01, far below the ultimate classical limit of C = 1. Scaling up this technique would substantially reduce the memory required in simulations of more complex systems. PMID:28168218

Does reactivation trigger episodic memory change? A meta-analysis.

PubMed

Scully, Iiona D; Napper, Lucy E; Hupbach, Almut

2017-07-01

According to the reconsolidation hypothesis, long-term memories return to a plastic state upon their reactivation, leaving them vulnerable to interference effects and requiring re-storage processes or else these memories might be permanently lost. The present study used a meta-analytic approach to critically evaluate the evidence for reactivation-induced changes in human episodic memory. Results indicated that reactivation makes episodic memories susceptible to physiological and behavioral interference. When applied shortly after reactivation, interference manipulations altered the amount of information that could be retrieved from the original learning event. This effect was more pronounced for remote memories and memories of narrative structure. Additionally, new learning following reactivation reliably increased the number of intrusions from new information into the original memory. These findings support a dynamic view of long-term memory by showing that memories can be changed long after they were acquired. Copyright © 2016 Elsevier Inc. All rights reserved.

Component processes of memory in alcoholism: pattern of compromise and neural substrates.

PubMed

Pitel, Anne-Lise; Eustache, Francis; Beaunieux, Helene

2014-01-01

Initially, alcohol-related memory deficits were considered only through the prism of Korsakoff's syndrome (KS). It is now clear, however, that chronic alcohol consumption results in memory disorders in alcoholics without ostensible neurologic complications, such as Wernicke's encephalopathy and KS. Most of the principal memory components are affected, including working memory, episodic memory, semantic memory, perceptual memory, and procedural memory. The extent of those cognitive impairments depends on several factors, such as age, gender, nutritional status, and psychiatric comorbidity. While memory disorders, especially episodic memory deficits, are largely definitive in patients with KS, recovery of memory abilities has been described with abstinence in uncomplicated alcoholics. Neuropsychologic impairments, and especially memory disorders, must be evaluated at alcohol treatment entry because they could impede patients from benefiting fully from cognitive and behavioral treatment approaches for alcohol dependence. Screening of memory deficits could also enable clinicians to detect, among alcoholics without ostensible neurologic complications, those at risk of developing permanent and debilitating amnesia that features KS. © 2014 Elsevier B.V. All rights reserved.

The role of retrieval mode and retrieval orientation in retrieval practice: insights from comparing recognition memory testing formats and restudying.

PubMed

Gao, Chuanji; Rosburg, Timm; Hou, Mingzhu; Li, Bingbing; Xiao, Xin; Guo, Chunyan

2016-12-01

The effectiveness of retrieval practice for aiding long-term memory, referred to as the testing effect, has been widely demonstrated. However, the specific neurocognitive mechanisms underlying this phenomenon remain unclear. In the present study, we sought to explore the role of pre-retrieval processes at initial testing on later recognition performance by using event-related potentials (ERPs). Subjects studied two lists of words (Chinese characters) and then performed a recognition task or a source memory task, or restudied the word lists. At the end of the experiment, subjects received a final recognition test based on the remember-know paradigm. Behaviorally, initial testing (active retrieval) enhanced memory retention relative to restudying (passive retrieval). The retrieval mode at initial testing was indexed by more positive-going ERPs for unstudied items in the active-retrieval tasks than in passive retrieval from 300 to 900 ms. Follow-up analyses showed that the magnitude of the early ERP retrieval mode effect (300-500 ms) was predictive of the behavioral testing effect later on. In addition, the ERPs for correctly rejected new items during initial testing differed between the two active-retrieval tasks from 500 to 900 ms, and this ERP retrieval orientation effect predicted differential behavioral testing gains between the two active-retrieval conditions. Our findings confirm that initial testing promotes later retrieval relative to restudying, and they further suggest that adopting pre-retrieval processing in the forms of retrieval mode and retrieval orientation might contribute to these memory enhancements.

Identity processes as a predictor of memory beliefs in older adults.

PubMed

Hilgeman, Michelle M; Allen, Rebecca S; Carden, Keisha D

2017-07-01

The impact of identity processes (identity assimilation, identity accommodation, and identity balance) on memory beliefs was explored. Individually administered questionnaires (e.g. depressive symptoms, subjective health, identity processes, memory beliefs) and a brief neuropsychological assessment of cognitive abilities were completed during a one-time interview with 82 participants aged 58-92 years-old (M = 74.68, SD = 10.95). Forty (49.4%) identified their race as White/Caucasian, 38 (46.9%) identified their race as Black/African American, and 3 (3.7%) indicated no primary racial/ethnic group. Hierarchical regression analyses revealed that identity processes account for differences in memory beliefs beyond established predictors. Specifically, identity accommodation and identity balance predicted memory self-efficacy beyond depression and subjective health. These findings are congruent with identity process theory; however, the impact of identity assimilation in this population was unremarkable. Exploratory analyses also indicated that the identity processes have a stronger relationship to some domains of memory self-efficacy (i.e. anxiety, capacity) than others (i.e. perceived change, locus of control). Beliefs about memory and their integration into an adaptable, yet consistent self-concept are an important element of identity for aging individuals. Additional research is needed to determine the unique role of identity accommodation and identity balance in understanding cognitive functioning and ultimately the impact on potential clinical applications, such as related health-seeking behavior among older adults. Tailored interventions could be developed to facilitate optimal utilization of health care services at a time when early diagnosis of memory-related disorders is critical for future planning and care decisions.

Effects of oxytocin on behavioral and ERP measures of recognition memory for own-race and other-race faces in women and men

PubMed Central

Herzmann, Grit; Bird, Christopher W.; Freeman, Megan; Curran, Tim

2013-01-01

Oxytocin has been shown to affect human social information processing including recognition memory for faces. Here we investigated the neural processes underlying the effect of oxytocin on memorizing own-race and other-race faces in men and women. In a placebo-controlled, doubleblind, between-subject study, participants received either oxytocin or placebo before studying own-race and other-race faces. We recorded event-related potentials (ERPs) during both the study and recognition phase to investigate neural correlates of oxytocin’s effect on memory encoding, memory retrieval, and perception. Oxytocin increased the accuracy of familiarity judgments in the recognition test. Neural correlates for this effect were found in ERPs related to memory encoding and retrieval but not perception. In contrast to its facilitating effects on familiarity, oxytocin impaired recollection judgments, but in men only. Oxytocin did not differentially affect own-race and other-race faces. This study shows that oxytocin influences memory, but not perceptual processes, in a face recognition task and is the first to reveal sex differences in the effect of oxytocin on face memory. Contrary to recent findings in oxytocin and moral decision making, oxytocin did not preferentially improve memory for own-race faces. PMID:23648370

Effects of oxytocin on behavioral and ERP measures of recognition memory for own-race and other-race faces in women and men.

PubMed

Herzmann, Grit; Bird, Christopher W; Freeman, Megan; Curran, Tim

2013-10-01

Oxytocin has been shown to affect human social information processing including recognition memory for faces. Here we investigated the neural processes underlying the effect of oxytocin on memorizing own-race and other-race faces in men and women. In a placebo-controlled, double-blind, between-subject study, participants received either oxytocin or placebo before studying own-race and other-race faces. We recorded event-related potentials (ERPs) during both the study and recognition phase to investigate neural correlates of oxytocin's effect on memory encoding, memory retrieval, and perception. Oxytocin increased the accuracy of familiarity judgments in the recognition test. Neural correlates for this effect were found in ERPs related to memory encoding and retrieval but not perception. In contrast to its facilitating effects on familiarity, oxytocin impaired recollection judgments, but in men only. Oxytocin did not differentially affect own-race and other-race faces. This study shows that oxytocin influences memory, but not perceptual processes, in a face recognition task and is the first to reveal sex differences in the effect of oxytocin on face memory. Contrary to recent findings in oxytocin and moral decision making, oxytocin did not preferentially improve memory for own-race faces. Copyright © 2013 Elsevier Ltd. All rights reserved.

Programmable permanent data storage characteristics of nanoscale thin films of a thermally stable aromatic polyimide.

PubMed

Kim, Dong Min; Park, Samdae; Lee, Taek Joon; Hahm, Suk Gyu; Kim, Kyungtae; Kim, Jin Chul; Kwon, Wonsang; Ree, Moonhor

2009-10-06

We have synthesized a new thermally and dimensionally stable polyimide, poly(4,4'-amino(4-hydroxyphenyl)diphenylene hexafluoroisopropylidenediphthalimide) (6F-HTPA PI). 6F-HTPA PI is soluble in organic solvents and is thus easily processed with conventional solution coating techniques to produce good quality nanoscale thin films. Devices fabricated with nanoscale thin PI films with thicknesses less than 77 nm exhibit excellent unipolar write-once-read-many-times (WORM) memory behavior with a high ON/OFF current ratio of up to 10(6), a long retention time and low power consumption, less than +/-3.0 V. Furthermore, these WORM characteristics were found to persist even at high temperatures up to 150 degrees C. The WORM memory behavior was found to be governed by trap-limited space-charge limited conduction and local filament formation. The conduction processes are dominated by hole injection. Thus the hydroxytriphenylamine moieties of the PI polymer might play a key role as hole trapping sites in the observed WORM memory behavior. The properties of 6F-HTPA PI make it a promising material for high-density and very stable programmable permanent data storage devices with low power consumption.

Phosphorylation of K[superscript +] Channels at Single Residues Regulates Memory Formation

ERIC Educational Resources Information Center

Vernon, Jeffrey; Irvine, Elaine E.; Peters, Marco; Jeyabalan, Jeshmi; Giese, K. Peter

2016-01-01

Phosphorylation is a ubiquitous post-translational modification of proteins, and a known physiological regulator of K[superscript +] channel function. Phosphorylation of K[superscript +] channels by kinases has long been presumed to regulate neuronal processing and behavior. Although circumstantial evidence has accumulated from behavioral studies…

MOLECULAR MECHANISMS OF FEAR LEARNING AND MEMORY

PubMed Central

Johansen, Joshua P.; Cain, Christopher K.; Ostroff, Linnaea E.; LeDoux, Joseph E.

2011-01-01

Pavlovian fear conditioning is a useful behavioral paradigm for exploring the molecular mechanisms of learning and memory because a well-defined response to a specific environmental stimulus is produced through associative learning processes. Synaptic plasticity in the lateral nucleus of the amygdala (LA) underlies this form of associative learning. Here we summarize the molecular mechanisms that contribute to this synaptic plasticity in the context of auditory fear conditioning, the form of fear conditioning best understood at the molecular level. We discuss the neurotransmitter systems and signaling cascades that contribute to three phases of auditory fear conditioning: acquisition, consolidation, and reconsolidation. These studies suggest that multiple intracellular signaling pathways, including those triggered by activation of Hebbian processes and neuromodulatory receptors, interact to produce neural plasticity in the LA and behavioral fear conditioning. Together, this research illustrates the power of fear conditioning as a model system for characterizing the mechanisms of learning and memory in mammals, and potentially for understanding fear related disorders, such as PTSD and phobias. PMID:22036561

The extended trajectory of hippocampal development: Implications for early memory development and disorder.

PubMed

Gómez, Rebecca L; Edgin, Jamie O

2016-04-01

Hippocampus has an extended developmental trajectory, with refinements occurring in the trisynaptic circuit until adolescence. While structural change should suggest a protracted course in behavior, some studies find evidence of precocious hippocampal development in the first postnatal year and continuity in memory processes beyond. However, a number of memory functions, including binding and relational inference, can be cortically supported. Evidence from the animal literature suggests that tasks often associated with hippocampus (visual paired comparison, binding of a visuomotor response) can be mediated by structures external to hippocampus. Thus, a complete examination of memory development will have to rule out cortex as a source of early memory competency. We propose that early memory must show properties associated with full function of the trisynaptic circuit to reflect "adult-like" memory function, mainly (1) rapid encoding of contextual details of overlapping patterns, and (2) retention of these details over sleep-dependent delays. A wealth of evidence suggests that these functions are not apparent until 18-24 months, with behavioral discontinuities reflecting shifts in the neural structures subserving memory beginning approximately at this point in development. We discuss the implications of these observations for theories of memory and for identifying and measuring memory function in populations with typical and atypical hippocampal function. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Prospective memory in context: Moving through a familiar space.

PubMed

Smith, Rebekah E; Hunt, R Reed; Murray, Amy E

2017-02-01

Successful completion of delayed intentions is a common but important aspect of daily behavior. Such behavior requires not only memory for the intended action but also recognition of the opportunity to perform that action, known collectively as prospective memory. The fact that prospective memory tasks occur in the midst of other activities is captured in laboratory tasks by embedding the prospective memory task in an ongoing activity. In many cases the requirement to perform the prospective memory task results in a reduction in ongoing performance relative to when the ongoing task is performed alone. This is referred to as the cost to the ongoing task and reflects the allocation of attentional resources to the prospective memory task. The current study examined the pattern of cost across the ongoing task when the ongoing task provided contextual information that in turn allowed participants to anticipate when target events would occur within the ongoing task. The availability of contextual information reduced ongoing task response times overall, with an increase in response times closer to the target locations (Experiments 1-3). The fourth study, drawing on the Event Segmentation Theory, provided support for the proposal made by the Preparatory Attentional and Memory Processes theory of prospective memory that decisions about the allocation of attention to the prospective memory task are more likely to be made at points of transition. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

How can transcranial magnetic stimulation be used to causally manipulate memory representations in the human brain?

PubMed

Widhalm, Morgan L; Rose, Nathan S

2018-06-27

We present a focused review on the utility of transcranial magnetic stimulation (TMS) for modulating memory, with a particular focus on multimodal approaches in which TMS is paired with neuroimaging methods (electroencephalography and magnetic resonance imaging (MRI)) to manipulate and measure working memory processes. We contrast the utility of TMS for manipulating memory with other forms of noninvasive brain stimulation, as well as different forms of TMS including single-pulse, paired-pulse and repetitive TMS protocols. We discuss the potential for TMS to address fundamental cognitive neuroscience questions about the nature of memory processes and representations, while acknowledging the considerable variability of behavioral and neural outcomes in TMS studies. Also discussed are the limitations of this technology, current advancements that have helped to defray the impact of these limitations, and suggestions for future directions in research and methodology. This article is categorized under: Neuroscience > Clinical Neuroscience Neuroscience > Cognition Psychology > Memory. © 2018 Wiley Periodicals, Inc.

Talker-specific learning in amnesia: Insight into mechanisms of adaptive speech perception

PubMed Central

Trude, Alison M.; Duff, Melissa C.; Brown-Schmidt, Sarah

2014-01-01

A hallmark of human speech perception is the ability to comprehend speech quickly and effortlessly despite enormous variability across talkers. However, current theories of speech perception do not make specific claims about the memory mechanisms involved in this process. To examine whether declarative memory is necessary for talker-specific learning, we tested the ability of amnesic patients with severe declarative memory deficits to learn and distinguish the accents of two unfamiliar talkers by monitoring their eye-gaze as they followed spoken instructions. Analyses of the time-course of eye fixations showed that amnesic patients rapidly learned to distinguish these accents and tailored perceptual processes to the voice of each talker. These results demonstrate that declarative memory is not necessary for this ability and points to the involvement of non-declarative memory mechanisms. These results are consistent with findings that other social and accommodative behaviors are preserved in amnesia and contribute to our understanding of the interactions of multiple memory systems in the use and understanding of spoken language. PMID:24657480

Sports training enhances visuo-spatial cognition regardless of open-closed typology

PubMed Central

Hsieh, Shu-Shih; Chen, Kuan-Fu; Chang, Yu-Kai

2017-01-01

The aim of this study was to investigate the effects of open and closed sport participation on visuo-spatial attention and memory performance among young adults. Forty-eight young adults—16 open-skill athletes, 16 closed-skill athletes, and 16 non-athletes controls—were recruited for the study. Both behavioral performance and event-related potential (ERP) measurement were assessed when participants performed non-delayed and delayed match-to-sample task that tested visuo-spatial attention and memory processing. Results demonstrated that regardless of training typology, the athlete groups exhibited shorter reaction times in both the visuo-spatial attention and memory conditions than the control group with no existence of speed-accuracy trade-off. Similarly, a larger P3 amplitudes were observed in both athlete groups than in the control group for the visuo-spatial memory condition. These findings suggest that sports training, regardless of typology, are associated with superior visuo-spatial attention and memory performance, and more efficient neural resource allocation in memory processing. PMID:28560098

Maternal Child-Centered Attributions and Harsh Discipline: The Moderating Role of Maternal Working Memory Across Socioeconomic Contexts

PubMed Central

Sturge-Apple, Melissa L.; Suor, Jennifer H.; Skibo, Michael A.

2015-01-01

Cognitive models of parenting give emphasis to the central role that parental cognitions may play in parental socialization goals. In particular, dual process models suggest that parental attribution styles affect the way parents interpret caregiving situations and enact behaviors, particularly within the realm of discipline. Although research has documented the negative behavioral repercussions of dysfunctional child-centered responsibility biases, there is heterogeneity in the level of these associations. Research has also demonstrated that parental working memory capacity may serve as an individual difference factor in influencing caregiving behaviors. Thus, our first aim was to document how maternal working memory capacity may moderate the association between mother’s dysfunctional child-oriented attributions and use of harsh discipline. In addition, from an ecological perspective, a second aim was to examine how socioeconomic risk may further potentiate the impact of maternal working memory. To accomplish these aims, a socioeconomically diverse sample of 185 mothers and their three-year old children were recruited to participate in a laboratory-based research assessment. Findings revealed that lower maternal working memory capacity may operate as a risk factor for attributional biases and harsh discipline, while higher working memory may serve as a protective factor in this relationship. Socioeconomic risk further moderated these findings. Results suggest that the moderating role of working memory may be particularly pronounced under conditions of socio-economic risk. The theoretical and clinical implications of these findings are discussed. PMID:25221969

Maternal child-centered attributions and harsh discipline: the moderating role of maternal working memory across socioeconomic contexts.

PubMed

Sturge-Apple, Melissa L; Suor, Jennifer H; Skibo, Michael A

2014-10-01

Cognitive models of parenting give emphasis to the central role that parental cognitions may play in parental socialization goals. In particular, dual process models suggest that parental attribution styles affect the way parents interpret caregiving situations and enact behaviors, particularly within the realm of discipline. Although research has documented the negative behavioral repercussions of dysfunctional child-centered responsibility biases, there is heterogeneity in the level of these associations. Research has also demonstrated that parental working memory capacity may serve as an individual difference factor in influencing caregiving behaviors. Thus, our first aim was to document how maternal working memory capacity may moderate the association between mother's dysfunctional child-oriented attributions and use of harsh discipline. In addition, from an ecological perspective, a second aim was to examine how socioeconomic risk may further potentiate the impact of maternal working memory. To accomplish these aims, a socioeconomically diverse sample of 185 mothers and their 3-year old children were recruited to participate in a laboratory-based research assessment. Findings revealed that lower maternal working memory capacity may operate as a risk factor for attributional biases and harsh discipline, and higher working memory may serve as a protective factor in this relationship. Socioeconomic risk further moderated these findings. Results suggest that the moderating role of working memory may be particularly pronounced under conditions of socioeconomic risk. The theoretical and clinical implications of these findings are discussed. (PsycINFO Database Record (c) 2014 APA, all rights reserved).

The nucleus accumbens and learning and memory.

PubMed

Setlow, B

1997-09-01

Recent research on the nucleus accumbens (NA) indicates that this brain region is involved in learning and memory processes in a way that is separable from its other well-known roles in behavior, such as motivation, reward, and locomotor activity. These findings have suggested that 1) the NA may be involved in declarative, or hippocampal formation-dependent learning and memory, and not in several other non-declarative forms of learning and memory, and 2) the NA may be selectively involved in certain stages of learning and memory. These characteristics suggest that the NA may be part of a larger striatal system which subserves acquisition and consolidation, but is not a site of long-term storage, of different forms of learning and memory.

Extinction after retrieval: effects on the associative and nonassociative components of remote contextual fear memory.

PubMed

Costanzi, Marco; Cannas, Sara; Saraulli, Daniele; Rossi-Arnaud, Clelia; Cestari, Vincenzo

2011-01-01

Long-lasting memories of adverse experiences are essential for individuals' survival but are also involved, in the form of recurrent recollections of the traumatic experience, in the aetiology of anxiety diseases (e.g., post-traumatic stress disorder [PTSD]). Extinction-based erasure of fear memories has long been pursued as a behavioral way to treat anxiety disorders; yet, such a procedure turns out to be transient, context-dependent, and ineffective unless it is applied immediately after trauma. Recent evidence indicates that, in both rats and humans, extinction training can prevent the return of fear if administered within the reconsolidation window, when memories become temporarily labile and susceptible of being updated. Here, we show that the reconsolidation-extinction procedure fails to prevent the spontaneous recovery of a remote contextual fear memory in a mouse model of PTSD, as well as the long-lasting behavioral abnormalities induced by traumatic experience on anxiety and in both social and cognitive domains (i.e., social withdrawal and spatial learning deficits). Such a failure appears to be related to the ineffectiveness of the reconsolidation-extinction procedure in targeting the pathogenic process of fear sensitization, a nonassociative component of traumatic memory that causes animals to react aberrantly to harmless stimuli. This indicates fear sensitization as a major target for treatments aimed at mitigating anxiety and the behavioral outcomes of traumatic experiences.

Instruct: An Example of the Role of Artificial Intelligence in Voice-Based Training Systems.

DTIC Science & Technology

1983-01-01

Lockhart , R.S. Levels of processing : A framework for memory research. Journal of Verbal Learning and Verbal Behavior, 1972, LT, pp. 6𔄁T-684. Ericsson...of covert student processing and knowledge levels from overt student behavior; and a curriculum driver that could use the student model to determine...concentration), then the task is said to be resource-limited. Whenever the performance level remains invariant to increased allocations of processing

Associative and Strategic Components of Episodic Memory: A Life-Span Dissociation

ERIC Educational Resources Information Center

Shing, Yee Lee; Werkle-Bergner, Markus; Li, Shu-Chen; Lindenberger, Ulman

2008-01-01

The authors investigated the strategic component (i.e., elaboration and organization of episodic features) and the associative component (i.e., binding processes) of episodic memory and their interactions in 4 age groups (10-12, 13-15, 20-25, and 70-75 years of age). On the basis of behavioral and neural evidence, the authors hypothesized that the…

Preschoolers with Down Syndrome Do Not yet Show the Learning and Memory Impairments Seen in Adults with Down Syndrome

ERIC Educational Resources Information Center

Roberts, Lynette V.; Richmond, Jenny L.

2015-01-01

Individuals with Down syndrome (DS) exhibit a behavioral phenotype of specific strengths and weaknesses, in addition to a generalized cognitive delay. In particular, adults with DS exhibit specific deficits in learning and memory processes that depend on the hippocampus, and there is some suggestion of impairments on executive function tasks that…

Changes in Processing of Masked Stimuli across Early- and Late-Night Sleep: A Study on Behavior and Brain Potentials

ERIC Educational Resources Information Center

Verleger, Rolf; Schuknecht, Simon-Vitus; Jaskowski, Piotr; Wagner, Ullrich

2008-01-01

Sleep has proven to support the memory consolidation in many tasks including learning of perceptual skills. Explicit, conscious types of memory have been demonstrated to benefit particularly from slow-wave sleep (SWS), implicit, non-conscious types particularly from rapid eye movement (REM) sleep. By comparing the effects of early-night sleep,…

Deep recurrent neural network reveals a hierarchy of process memory during dynamic natural vision.

PubMed

Shi, Junxing; Wen, Haiguang; Zhang, Yizhen; Han, Kuan; Liu, Zhongming

2018-05-01

The human visual cortex extracts both spatial and temporal visual features to support perception and guide behavior. Deep convolutional neural networks (CNNs) provide a computational framework to model cortical representation and organization for spatial visual processing, but unable to explain how the brain processes temporal information. To overcome this limitation, we extended a CNN by adding recurrent connections to different layers of the CNN to allow spatial representations to be remembered and accumulated over time. The extended model, or the recurrent neural network (RNN), embodied a hierarchical and distributed model of process memory as an integral part of visual processing. Unlike the CNN, the RNN learned spatiotemporal features from videos to enable action recognition. The RNN better predicted cortical responses to natural movie stimuli than the CNN, at all visual areas, especially those along the dorsal stream. As a fully observable model of visual processing, the RNN also revealed a cortical hierarchy of temporal receptive window, dynamics of process memory, and spatiotemporal representations. These results support the hypothesis of process memory, and demonstrate the potential of using the RNN for in-depth computational understanding of dynamic natural vision. © 2018 Wiley Periodicals, Inc.

Strategic and Nonstrategic Information Acquisition.

ERIC Educational Resources Information Center

Berger, Charles R.

2002-01-01

Uses dual-process theories and research concerned with automaticity and the role conceptual short-term memory plays in visual information processing to illustrate both the ubiquity of nonstrategic information acquisition during interpersonal communication and its potential consequences on judgments and behavior. Discusses theoretical and…

N400 Event-Related Potential and Standardized Measures of Reading in Late Elementary School Children: Correlated or Independent?

ERIC Educational Resources Information Center

Coch, Donna; Benoit, Clarisse

2015-01-01

We investigated whether and how standardized behavioral measures of reading and electrophysiological measures of reading were related in 72 typically developing, late elementary school children. Behavioral measures included standardized tests of spelling, phonological processing, vocabulary, comprehension, naming speed, and memory.…

Preservation of hippocampal neuron numbers and hippocampal subfield volumes in behaviorally characterized aged tree shrews.

PubMed

Keuker, Jeanine I H; de Biurrun, Gabriel; Luiten, Paul G M; Fuchs, Eberhard

2004-01-19

Aging is associated with a decreased ability to store and retrieve information. The hippocampal formation plays a critical role in such memory processes, and its integrity is affected during normal aging. We used tree shrews (Tupaia belangeri) as an animal model of aging, because in many characteristics, tree shrews are closer to primates than they are to rodents. Young and aged male tree shrews performed a holeboard spatial memory task, which permits assessment of reference and working memory. Upon completion of the behavioral measurements, we carried out modified stereological analyses of neuronal numbers in various subdivisions of the hippocampus and used the Cavalieri method to calculate the volumes of these subfields. Results showed that the working memory of aged tree shrews was significantly impaired compared with that of young animals, whereas the hippocampus-dependent reference memory remained unchanged by aging. Estimation of the number of neurons revealed preserved neuron numbers in the subiculum, in the subregions CA1, CA2, CA3, and in the hilus of the dentate gyrus. Volume measurements showed no aging-related changes in the volume of any of these hippocampal subregions, or in the molecular and granule cell layers of the dentate gyrus of tree shrews. We conclude that the observed changes in memory performance in aging tree shrews are not accompanied by observable reductions of hippocampal neuron numbers or hippocampal volume, rather, the changes in memory performance are more likely the result of modified subcellular mechanisms that are affected by the aging process. Copyright 2003 Wiley-Liss, Inc.

From brain synapses to systems for learning and memory: Object recognition, spatial navigation, timed conditioning, and movement control.

PubMed

Grossberg, Stephen

2015-09-24

This article provides an overview of neural models of synaptic learning and memory whose expression in adaptive behavior depends critically on the circuits and systems in which the synapses are embedded. It reviews Adaptive Resonance Theory, or ART, models that use excitatory matching and match-based learning to achieve fast category learning and whose learned memories are dynamically stabilized by top-down expectations, attentional focusing, and memory search. ART clarifies mechanistic relationships between consciousness, learning, expectation, attention, resonance, and synchrony. ART models are embedded in ARTSCAN architectures that unify processes of invariant object category learning, recognition, spatial and object attention, predictive remapping, and eye movement search, and that clarify how conscious object vision and recognition may fail during perceptual crowding and parietal neglect. The generality of learned categories depends upon a vigilance process that is regulated by acetylcholine via the nucleus basalis. Vigilance can get stuck at too high or too low values, thereby causing learning problems in autism and medial temporal amnesia. Similar synaptic learning laws support qualitatively different behaviors: Invariant object category learning in the inferotemporal cortex; learning of grid cells and place cells in the entorhinal and hippocampal cortices during spatial navigation; and learning of time cells in the entorhinal-hippocampal system during adaptively timed conditioning, including trace conditioning. Spatial and temporal processes through the medial and lateral entorhinal-hippocampal system seem to be carried out with homologous circuit designs. Variations of a shared laminar neocortical circuit design have modeled 3D vision, speech perception, and cognitive working memory and learning. A complementary kind of inhibitory matching and mismatch learning controls movement. This article is part of a Special Issue entitled SI: Brain and Memory. Copyright © 2014 Elsevier B.V. All rights reserved.

[Formula: see text]Executive functions and social information processing in adolescents with severe behavior problems.

PubMed

Van Nieuwenhuijzen, M; Van Rest, M M; Embregts, P J C M; Vriens, A; Oostermeijer, S; Van Bokhoven, I; Matthys, W

2017-02-01

One tradition in research for explaining aggression and antisocial behavior has focused on social information processing (SIP). Aggression and antisocial behavior have also been studied from the perspective of executive functions (EFs), the higher-order cognitive abilities that affect other cognitive processes, such as social cognitive processes. The main goal of the present study is to provide insight into the relation between EFs and SIP in adolescents with severe behavior problems. Because of the hierarchical relation between EFs and SIP, we examined EFs as predictors of SIP. We hypothesized that, first, focused attention predicts encoding and interpretation, second, inhibition predicts interpretation, response generation, evaluation, and selection, and third, working memory predicts response generation and selection. The participants consisted of 94 respondents living in residential facilities aged 12-20 years, all showing behavior problems in the clinical range according to care staff. EFs were assessed using subtests from the Amsterdam Neuropsychological Test battery. Focused attention was measured by the Flanker task, inhibition by the GoNoGo task, and working memory by the Visual Spatial Sequencing task. SIP was measured by video vignettes and a structured interview. The results indicate that positive evaluation of aggressive responses is predicted by impaired inhibition and selection of aggressive responses by a combination of impaired focused attention and inhibition. It is concluded that different components of EFs as higher-order cognitive abilities affect SIP.

A reduction in hippocampal GABAA receptor alpha5 subunits disrupts the memory for location of objects in mice.

PubMed

Prut, L; Prenosil, G; Willadt, S; Vogt, K; Fritschy, J-M; Crestani, F

2010-07-01

The memory for location of objects, which binds information about objects to discrete positions or spatial contexts of occurrence, is a form of episodic memory particularly sensitive to hippocampal damage. Its early decline is symptomatic for elderly dementia. Substances that selectively reduce alpha5-GABA(A) receptor function are currently developed as potential cognition enhancers for Alzheimer's syndrome and other dementia, consistent with genetic studies implicating these receptors that are highly expressed in hippocampus in learning performance. Here we explored the consequences of reduced GABA(A)alpha5-subunit contents, as occurring in alpha5(H105R) knock-in mice, on the memory for location of objects. This required the behavioral characterization of alpha5(H105R) and wild-type animals in various tasks examining learning and memory retrieval strategies for objects, locations, contexts and their combinations. In mutants, decreased amounts of alpha5-subunits and retained long-term potentiation in hippocampus were confirmed. They exhibited hyperactivity with conserved circadian rhythm in familiar actimeters, and normal exploration and emotional reactivity in novel places, allocentric spatial guidance, and motor pattern learning acquisition, inhibition and flexibility in T- and eight-arm mazes. Processing of object, position and context memories and object-guided response learning were spared. Genotype difference in object-in-place memory retrieval and in encoding and response learning strategies for object-location combinations manifested as a bias favoring object-based recognition and guidance strategies over spatial processing of objects in the mutants. These findings identify in alpha5(H105R) mice a behavioral-cognitive phenotype affecting basal locomotion and the memory for location of objects indicative of hippocampal dysfunction resulting from moderately decreased alpha5-subunit contents.

Neural correlates of impaired cognitive control over working memory in schizophrenia.

PubMed

Eich, Teal S; Nee, Derek Evan; Insel, Catherine; Malapani, Chara; Smith, Edward E

2014-07-15

One of the most common deficits in patients with schizophrenia (SZ) is in working memory (WM), which has wide-reaching impacts across cognition. However, previous approaches to studying WM in SZ have used tasks that require multiple cognitive-control processes, making it difficult to determine which specific cognitive and neural processes underlie the WM impairment. We used functional magnetic resonance imaging to investigate component processes of WM in SZ. Eighteen healthy controls (HCs) and 18 patients with SZ performed an item-recognition task that permitted separate neural assessments of 1) WM maintenance, 2) inhibition, and 3) interference control in response to recognition probes. Before inhibitory demands, posterior ventrolateral prefrontal cortex (VLPFC), an area involved in WM maintenance, was activated to a similar degree in both HCs and patients, indicating preserved maintenance operations in SZ. When cued to inhibit items from WM, HCs showed reduced activation in posterior VLPFC, commensurate with appropriately inhibiting items from WM. However, these inhibition-related reductions were absent in patients. When later probed with items that should have been inhibited, patients showed reduced behavioral performance and increased activation in mid-VLPFC, an area implicated in interference control. A mediation analysis indicated that impaired inhibition led to increased reliance on interference control and reduced behavioral performance. In SZ, impaired control over memory, manifested through proactive inhibitory deficits, leads to increased reliance on reactive interference-control processes. The strain on interference-control processes results in reduced behavioral performance. Thus, inhibitory deficits in SZ may underlie widespread impairments in WM and cognition. © 2013 Society of Biological Psychiatry Published by Society of Biological Psychiatry All rights reserved.

Asymmetric effects of emotion on mnemonic interference

PubMed Central

Leal, Stephanie L.; Tighe, Sarah K.; Yassa, Michael A.

2014-01-01

Emotional experiences can strengthen memories so that they can be used to guide future behavior. Emotional arousal, mediated by the amygdala, is thought to modulate storage by the hippocampus, which may encode unique episodic memories via pattern separation – the process by which similar memories are stored using non-overlapping representations. While prior work has examined mnemonic interference due to similarity and emotional modulation of memory independently, examining the mechanisms by which emotion influences mnemonic interference has not been previously accomplished in humans. To this end, we developed an emotional memory task where emotional content and stimulus similarity were varied to examine the effect of emotion on fine mnemonic discrimination (a putative behavioral correlate of hippocampal pattern separation). When tested immediately after encoding, discrimination was reduced for similar emotional items compared to similar neutral items, consistent with a reduced bias towards pattern separation. After 24 h, recognition of emotional target items was preserved compared to neutral items, whereas similar emotional item discrimination was further diminished. This suggests a potential mechanism for the emotional modulation of memory with a selective remembering of gist, as well as a selective forgetting of detail, indicating an emotion-induced reduction in pattern separation. This can potentially increase the effective signal-to-noise ratio in any given situation to promote survival. Furthermore, we found that individuals with depressive symptoms hyper-discriminate negative items, which correlated with their symptom severity. This suggests that utilizing mnemonic discrimination paradigms allows us to tease apart the nuances of disorders with aberrant emotional mnemonic processing. PMID:24607286

The Newell Test Should Commit to Diagnosing Dysfunctions

NASA Technical Reports Server (NTRS)

Clancey, William J.

2003-01-01

"Conceptual coordination" analysis bridges connectionism and symbolic approaches by posting a "process memory" by which categories are physically coordinated (as neural networks) in time. Focusing on dysfunctions and odd behaviors like slips reveals the function of consciousness, especially taken-for-granted constructive processes, different from conventional programming constructs. Newell strongly endorsed identifying architectural limits; the heuristic of "diagnose unusual behaviors" will provide targets of opportunity that greatly strengthens the Newell Test.

Memory for Drug Related Visual Stimuli in Young Adult, Cocaine Dependent Polydrug Users

PubMed Central

Ray, Suchismita; Pandina, Robert; Bates, Marsha E.

2015-01-01

Background and Objectives Implicit (unconscious) and explicit (conscious) memory associations with drugs have been examined primarily using verbal cues. However, drug seeking, drug use behaviors, and relapse in chronic cocaine and other drug users are frequently triggered by viewing substance related visual cues in the environment. We thus examined implicit and explicit memory for drug picture cues to understand the relative extent to which conscious and unconscious memory facilitation of visual drug cues occurs during cocaine dependence. Methods Memory for drug related and neutral picture cues was assessed in 14 inpatient cocaine dependent polydrug users and a comparison group of 21 young adults with limited drug experience (N = 35). Participants completed picture cue exposure, free recall and recognition tasks to assess explicit memory, and a repetition priming task to assess implicit memory. Results Drug cues, compared to neutral cues were better explicitly recalled and implicitly primed, and especially so in the cocaine group. In contrast, neutral cues were better explicitly recognized, and especially in the control group. Conclusion Certain forms of explicit and implicit memory for drug cues were enhanced in cocaine users compared to controls when memory was tested a short time following cue exposure. Enhanced unconscious memory processing of drug cues in chronic cocaine users may be a behavioral manifestation of heightened drug cue salience that supports drug seeking and taking. There may be value in expanding intervention techniques to utilize cocaine users’ implicit memory system. PMID:24588421

Parasitic resistive switching uncovered from complementary resistive switching in single active-layer oxide memory device

NASA Astrophysics Data System (ADS)

Zhu, Lisha; Hu, Wei; Gao, Chao; Guo, Yongcai

2017-12-01

This paper reports the reversible transition processes between the bipolar and complementary resistive switching (CRS) characteristics on the binary metal-oxide resistive memory devices of Pt/HfO x /TiN and Pt/TaO x /TiN by applying the appropriate bias voltages. More interestingly, by controlling the amplitude of the negative bias, the parasitic resistive switching effect exhibiting repeatable switching behavior is uncovered from the CRS behavior. The electrical observation of the parasitic resistive switching effect can be explained by the controlled size of the conductive filament. This work confirms the transformation and interrelationship among the bipolar, parasitic, and CRS effects, and thus provides new insight into the understanding of the physical mechanism of the binary metal-oxide resistive switching memory devices.

A Tradeoff Between Accuracy and Flexibility in a Working Memory Circuit Endowed with Slow Feedback Mechanisms

PubMed Central

Pereira, Jacinto; Wang, Xiao-Jing

2015-01-01

Recent studies have shown that reverberation underlying mnemonic persistent activity must be slow, to ensure the stability of a working memory system and to give rise to long neural transients capable of accumulation of information over time. Is the slower the underlying process, the better? To address this question, we investigated 3 slow biophysical mechanisms that are activity-dependent and prominently present in the prefrontal cortex: Depolarization-induced suppression of inhibition (DSI), calcium-dependent nonspecific cationic current (ICAN), and short-term facilitation. Using a spiking network model for spatial working memory, we found that these processes enhance the memory accuracy by counteracting noise-induced drifts, heterogeneity-induced biases, and distractors. Furthermore, the incorporation of DSI and ICAN enlarges the range of network's parameter values required for working memory function. However, when a progressively slower process dominates the network, it becomes increasingly more difficult to erase a memory trace. We demonstrate this accuracy–flexibility tradeoff quantitatively and interpret it using a state-space analysis. Our results supports the scenario where N-methyl-d-aspartate receptor-dependent recurrent excitation is the workhorse for the maintenance of persistent activity, whereas slow synaptic or cellular processes contribute to the robustness of mnemonic function in a tradeoff that potentially can be adjusted according to behavioral demands. PMID:25253801

Sentence processing and verbal working memory in a white-matter-disconnection patient.

PubMed

Meyer, Lars; Cunitz, Katrin; Obleser, Jonas; Friederici, Angela D

2014-08-01

The Arcuate Fasciculus/Superior Longitudinal Fasciculus (AF/SLF) is the white-matter bundle that connects posterior superior temporal and inferior frontal cortex. Its causal functional role in sentence processing and verbal working memory is currently under debate. While impairments of sentence processing and verbal working memory often co-occur in patients suffering from AF/SLF damage, it is unclear whether these impairments result from shared white-matter damage to the verbal-working-memory network. The present study sought to specify the behavioral consequences of focal AF/SLF damage for sentence processing and verbal working memory, which were assessed in a single patient suffering from a cleft-like lesion spanning the deep left superior temporal gyrus, sparing most surrounding gray matter. While tractography suggests that the ventral fronto-temporal white-matter bundle is intact in this patient, the AF/SLF was not visible to tractography. In line with the hypothesis that the AF/SLF is causally involved in sentence processing, the patient׳s performance was selectively impaired on sentences that jointly involve both complex word orders and long word-storage intervals. However, the patient was unimpaired on sentences that only involved long word-storage intervals without involving complex word orders. On the contrary, the patient performed generally worse than a control group across standard verbal-working-memory tests. We conclude that the AF/SLF not only plays a causal role in sentence processing, linking regions of the left dorsal inferior frontal gyrus to the temporo-parietal region, but moreover plays a crucial role in verbal working memory, linking regions of the left ventral inferior frontal gyrus to the left temporo-parietal region. Together, the specific sentence-processing impairment and the more general verbal-working-memory impairment may imply that the AF/SLF subserves both sentence processing and verbal working memory, possibly pointing to the AF and SLF respectively supporting each. Copyright © 2014 Elsevier Ltd. All rights reserved.

Effect of supplementation with long-chain ω-3 polyunsaturated fatty acids on behavior and cognition in children with attention deficit/hyperactivity disorder (ADHD): a randomized placebo-controlled intervention trial.

PubMed

Widenhorn-Müller, Katharina; Schwanda, Simone; Scholz, Elke; Spitzer, Manfred; Bode, Harald

2014-01-01

To determine whether supplementation with the long-chain omega-3 polyunsaturated fatty acids eicosapentaenoic (EPA) and docosahexaenoic acid (DHA) affects behavioral symptoms and cognitive impairments in children 6-12 years of age diagnosed with attention-deficit/hyperactivity disorder (ADHD). The randomized, double-blind placebo-controlled 16 weeks trial was conducted with 95 children diagnosed with ADHD according to DSM-IV criteria. Behavior was assessed by parents, teachers and investigators using standardized rating scales and questionnaires. Further outcome variables were working memory, speed of information processing and various measures of attention. For a subgroup of 81 participants, erythrocyte membrane fatty acid composition was analyzed before and after the intervention. Supplementation with the omega-3 fatty acid mix increased EPA and DHA concentrations in erythrocyte membranes and improved working memory function, but had no effect on other cognitive measures and parent- and teacher-rated behavior in the study population. Improved working memory correlated significantly with increased EPA, DHA and decreased AA (arachidonic acid). Copyright © 2014 Elsevier Ltd. All rights reserved.

Neurophysiology and Rationality in Political Thinking.

ERIC Educational Resources Information Center

Peterson, Steven A.

Research both in cognitive psychology and psychobiology suggests that political behavior is often less rational than individuals believe it to be. Information processing, memory, and decision making are interlinked processes. Studies in cognitive psychology reveal that even though decision making requires rationality, individuals often adopt…

Brain sites involved in fear memory reconsolidation and extinction of rodents.

PubMed

Baldi, Elisabetta; Bucherelli, Corrado

2015-06-01

Fear memory is a motivational system essential for organisms survival having a central role in organization of defensive behaviors to threat. In the last years there has been a growing interest on conditioned fear memory reconsolidation and extinction, two specific phases of memorization process, both induced by memory retrieval. Understanding the mechanisms underlying these two mnemonic processes may allow to work out therapeutic interventions for treatment of human fear and anxiety disorders, such as specific phobias and post-traumatic stress disorder. Based on the use of one-trial conditioning paradigms, which allow to follow the evolution of a mnemonic trace in its various phases, the present paper has attempted to reorganize the current literature relative to the rodents highlighting both the role of several brain structures in conditioned fear memory reconsolidation and extinction and the selective cellular processes involved. A crucial role seems to be play by medial prefrontal cortex, in particular by prelimbic and infralimbic cortices, and by distinct connections between them and the amygdala, hippocampus and entorhinal cortex. Copyright © 2015 Elsevier Ltd. All rights reserved.

Linking agent-based models and stochastic models of financial markets

PubMed Central

Feng, Ling; Li, Baowen; Podobnik, Boris; Preis, Tobias; Stanley, H. Eugene

2012-01-01

It is well-known that financial asset returns exhibit fat-tailed distributions and long-term memory. These empirical features are the main objectives of modeling efforts using (i) stochastic processes to quantitatively reproduce these features and (ii) agent-based simulations to understand the underlying microscopic interactions. After reviewing selected empirical and theoretical evidence documenting the behavior of traders, we construct an agent-based model to quantitatively demonstrate that “fat” tails in return distributions arise when traders share similar technical trading strategies and decisions. Extending our behavioral model to a stochastic model, we derive and explain a set of quantitative scaling relations of long-term memory from the empirical behavior of individual market participants. Our analysis provides a behavioral interpretation of the long-term memory of absolute and squared price returns: They are directly linked to the way investors evaluate their investments by applying technical strategies at different investment horizons, and this quantitative relationship is in agreement with empirical findings. Our approach provides a possible behavioral explanation for stochastic models for financial systems in general and provides a method to parameterize such models from market data rather than from statistical fitting. PMID:22586086

Linking agent-based models and stochastic models of financial markets.

PubMed

Feng, Ling; Li, Baowen; Podobnik, Boris; Preis, Tobias; Stanley, H Eugene

2012-05-29

It is well-known that financial asset returns exhibit fat-tailed distributions and long-term memory. These empirical features are the main objectives of modeling efforts using (i) stochastic processes to quantitatively reproduce these features and (ii) agent-based simulations to understand the underlying microscopic interactions. After reviewing selected empirical and theoretical evidence documenting the behavior of traders, we construct an agent-based model to quantitatively demonstrate that "fat" tails in return distributions arise when traders share similar technical trading strategies and decisions. Extending our behavioral model to a stochastic model, we derive and explain a set of quantitative scaling relations of long-term memory from the empirical behavior of individual market participants. Our analysis provides a behavioral interpretation of the long-term memory of absolute and squared price returns: They are directly linked to the way investors evaluate their investments by applying technical strategies at different investment horizons, and this quantitative relationship is in agreement with empirical findings. Our approach provides a possible behavioral explanation for stochastic models for financial systems in general and provides a method to parameterize such models from market data rather than from statistical fitting.

Theta oscillations during holeboard training in rats: different learning strategies entail different context-dependent modulations in the hippocampus.

PubMed

Woldeit, M L; Korz, V

2010-02-03

A functional connection between theta rhythms, information processing, learning and memory formation is well documented by studies focusing on the impact of theta waves on motor activity, global context or phase coding in spatial learning. In the present study we analyzed theta oscillations during a spatial learning task and assessed which specific behavioral contexts were connected to changes in theta power and to the formation of memory. Therefore, we measured hippocampal dentate gyrus theta modulations in male rats that were allowed to establish a long-term spatial reference memory in a holeboard (fixed pattern of baited holes) in comparison to rats that underwent similar training conditions but could not form a reference memory (randomly baited holes). The first group established a pattern specific learning strategy, while the second developed an arbitrary search strategy, visiting increasingly more holes during training. Theta power was equally influenced during the training course in both groups, but was significantly higher when compared to untrained controls. A detailed behavioral analysis, however, revealed behavior- and context-specific differences within the experimental groups. In spatially trained animals theta power correlated with the amounts of reference memory errors in the context of the inspection of unbaited holes and exploration in which, as suggested by time frequency analyses, also slow wave (delta) power was increased. In contrast, in randomly trained animals positive correlations with working memory errors were found in the context of rearing behavior. These findings indicate a contribution of theta/delta to long-lasting memory formation in spatially trained animals, whereas in pseudo trained animals theta seems to be related to attention in order to establish trial specific short-term working memory. Implications for differences in neuronal plasticity found in earlier studies are discussed. Copyright 2010 IBRO. Published by Elsevier Ltd. All rights reserved.

Serotonergic mechanisms in addiction-related memories.

PubMed

Nic Dhonnchadha, Bríd A; Cunningham, Kathryn A

2008-12-16

Drug-associated memories are a hallmark of addiction and a contributing factor in the continued use and relapse to drugs of abuse. Repeated association of drugs of abuse with conditioned stimuli leads to long-lasting behavioral responses that reflect reward-controlled learning and participate in the establishment of addiction. A greater understanding of the mechanisms underlying the formation and retrieval of drug-associated memories may shed light on potential therapeutic approaches to effectively intervene with drug use-associated memory. There is evidence to support the involvement of serotonin (5-HT) neurotransmission in learning and memory formation through the families of the 5-HT(1) receptor (5-HT(1)R) and 5-HT(2)R which have also been shown to play a modulatory role in the behavioral effects induced by many psychostimulants. While there is a paucity of studies examining the effects of selective 5-HT(1A)R ligands, the available dataset suggests that 5-HT(1B)R agonists may inhibit retrieval of cocaine-associated memories. The 5-HT(2A)R and 5-HT(2C)R appear to be integral in the strong conditioned associations made between cocaine and environmental cues with 5-HT(2A)R antagonists and 5-HT(2C)R agonists possessing potency in blocking retrieval of cocaine-associated memories following cocaine self-administration procedures. The complex anatomical connectivity between 5-HT neurons and other neuronal phenotypes in limbic-corticostriatal brain structures, the heterogeneity of 5-HT receptors (5-HT(X)R) and the conflicting results of behavioral experiments which employ non-specific 5-HT(X)R ligands contribute to the complexity of interpreting the involvement of 5-HT systems in addictive-related memory processes. This review briefly traces the history of 5-HT involvement in retrieval of drug-cue associations and future targets of serotonergic manipulation that may reduce the impact that drug cues have on addictive behavior and relapse.

Serotonergic Mechanisms in Addiction-Related Memories

PubMed Central

Nic Dhonnchadha, Bríd Á; Cunningham, Kathryn A.

2008-01-01

Drug-associated memories are a hallmark of addiction and a contributing factor in the continued use and relapse to drugs of abuse. Repeated association of drugs of abuse with conditioned stimuli leads to long-lasting behavioral responses that reflect reward-controlled learning and participate in the establishment of addiction. A greater understanding of the mechanisms underlying the formation and retrieval of drug-associated memories may shed light on potential therapeutic approaches to effectively intervene with drug use-associated memory. There is evidence to support the involvement of serotonin (5-HT) neurotransmission in learning and memory formation through the families of the 5-HT1 receptor (5-HT1R) and 5-HT2R which have also been shown to play a modulatory role in the behavioral effects induced by many psychostimulants. While there is a paucity of studies examining the effects of selective 5-HT1AR ligands, the available dataset suggests that 5-HT1BR agonists may inhibit retrieval of cocaine-associated memories. The 5-HT2AR and 5-HT2CR appear to be integral in the strong conditioned associations made between cocaine and environmental cues with 5-HT2AR antagonists and 5-HT2CR agonists possessing potency in blocking retrieval of cocaine-associated memories following cocaine self-administration procedures. The complex anatomical connectivity between 5-HT neurons and other neuronal phenotypes in limbic-corticostriatal brain structures, the heterogeneity of 5-HT receptors (5-HTXR) and the conflicting results of behavioral experiments which employ non-specific 5-HTXR ligands contribute to the complexity of interpreting the involvement of 5-HT systems in addictive-related memory processes. This review briefly traces the history of 5-HT involvement in retrieval of drug-cue associations and future targets of serotonergic manipulation that may reduce the impact that drug cues have on addictive behavior and relapse. PMID:18639587

Exploring the switching of the focus of attention within working memory: A combined event-related potential and behavioral study.

PubMed

Frenken, Marius; Berti, Stefan

2018-04-01

Working memory enables humans to maintain selected information for cognitive processes and ensures instant access to the memorized contents. Theories suggest that switching the focus of attention between items within working memory realizes the access. This is reflected in object-switching costs in response times when the item for the task processing is to be changed. Another correlate of attentional allocation in working memory is the P3a-component of the human event-related potential. The aim of this study was to demonstrate that switching of attention within working memory is a separable processing step. Participants completed a cued memory-updating task in which they were instructed to update one memory item at a time out of a memory list of four digits by applying a mathematical operation indicated by a target sign. The hypotheses predicted (1) prolonged updating times in switch (different item compared to previous trial) versus repetition trials (same item), (2) an influence of cues (valid/neutral) presented before the mathematical target on switching costs, and (3) that the P3a-component is more pronounced in the cue-target interval in the valid cue condition and more pronounced in the post-target interval in the neutral cue condition. A student's t-test verified the first hypothesis, repeated-measurement analyses of variance demonstrated that hypotheses 2 and 3 should be rejected. Results suggest that switching of attention within working memory could not be separated from further processing steps and retro-cue benefits are not due to a head start of retrieval as well as that switch costs represent internal processes. Copyright © 2018 Elsevier B.V. All rights reserved.

Cognitive Consilience: Primate Non-Primary Neuroanatomical Circuits Underlying Cognition

PubMed Central

Solari, Soren Van Hout; Stoner, Rich

2011-01-01

Interactions between the cerebral cortex, thalamus, and basal ganglia form the basis of cognitive information processing in the mammalian brain. Understanding the principles of neuroanatomical organization in these structures is critical to understanding the functions they perform and ultimately how the human brain works. We have manually distilled and synthesized hundreds of primate neuroanatomy facts into a single interactive visualization. The resulting picture represents the fundamental neuroanatomical blueprint upon which cognitive functions must be implemented. Within this framework we hypothesize and detail 7 functional circuits corresponding to psychological perspectives on the brain: consolidated long-term declarative memory, short-term declarative memory, working memory/information processing, behavioral memory selection, behavioral memory output, cognitive control, and cortical information flow regulation. Each circuit is described in terms of distinguishable neuronal groups including the cerebral isocortex (9 pyramidal neuronal groups), parahippocampal gyrus and hippocampus, thalamus (4 neuronal groups), basal ganglia (7 neuronal groups), metencephalon, basal forebrain, and other subcortical nuclei. We focus on neuroanatomy related to primate non-primary cortical systems to elucidate the basis underlying the distinct homotypical cognitive architecture. To display the breadth of this review, we introduce a novel method of integrating and presenting data in multiple independent visualizations: an interactive website (http://www.frontiersin.org/files/cognitiveconsilience/index.html) and standalone iPhone and iPad applications. With these tools we present a unique, annotated view of neuroanatomical consilience (integration of knowledge). PMID:22194717

Development of a water-escape motivated version of the Stone T-maze for mice

PubMed Central

Pistell, Paul J.; Ingram, Donald K.

2014-01-01

Mice provide a highly valuable resource for investigating learning and memory processes; however, many of the established tasks for evaluating learning and memory were developed for rats. Behaviors of mice in these tasks appear to be driven by different motivational factors, and as a result, they often do not perform reliably on tasks involving rewards traditionally used for rats. Because of difficulties in measuring learning and memory in mice as well as the need to have a task that can reliably measure these behavioral processes, we have developed a mouse version of the Stone T-maze utilizing what appears to be the primary motivation of mice, escape to a safe location. Specifically, we have constructed a task that requires the mouse to wade through water to reach a dark and dry goal box. To escape this aversive environment, the Stone T-maze requires learning the correct sequence of 13 left and right turns to reach the goal box. Through a series of experiments examining a variety of protocols, it was found that mice will reliably perform this task. This task can be used to assess learning and memory without the potential performance confounds that can affect performance of mice in other tasks. We believe this task offers a valuable new tool for evaluating learning and memory in mice not previously available to researchers. PMID:20026250

Inhibition of histone deacetylase 3 via RGFP966 facilitates cortical plasticity underlying unusually accurate auditory associative cue memory for excitatory and inhibitory cue-reward associations.

PubMed

Shang, Andrea; Bylipudi, Sooraz; Bieszczad, Kasia M

2018-05-31

Epigenetic mechanisms are key for regulating long-term memory (LTM) and are known to exert control on memory formation in multiple systems of the adult brain, including the sensory cortex. One epigenetic mechanism is chromatin modification by histone acetylation. Blocking the action of histone de-acetylases (HDACs) that normally negatively regulate LTM by repressing transcription has been shown to enable memory formation. Indeed, HDAC inhibition appears to facilitate memory by altering the dynamics of gene expression events important for memory consolidation. However, less understood are the ways in which molecular-level consolidation processes alter subsequent memory to enhance storage or facilitate retrieval. Here we used a sensory perspective to investigate whether the characteristics of memory formed with HDAC inhibitors are different from naturally-formed memory. One possibility is that HDAC inhibition enables memory to form with greater sensory detail than normal. Because the auditory system undergoes learning-induced remodeling that provides substrates for sound-specific LTM, we aimed to identify behavioral effects of HDAC inhibition on memory for specific sound features using a standard model of auditory associative cue-reward learning, memory, and cortical plasticity. We found that three systemic post-training treatments of an HDAC3-inhibitor (RGPF966, Abcam Inc.) in rats in the early phase of training facilitated auditory discriminative learning, changed auditory cortical tuning, and increased the specificity for acoustic frequency formed in memory of both excitatory (S+) and inhibitory (S-) associations for at least 2 weeks. The findings support that epigenetic mechanisms act on neural and behavioral sensory acuity to increase the precision of associative cue memory, which can be revealed by studying the sensory characteristics of long-term associative memory formation with HDAC inhibitors. Published by Elsevier B.V.

Thickness effect of nickel oxide thin films on associated solution-processed write-once-read-many-times memory devices

NASA Astrophysics Data System (ADS)

Wang, Xiao Lin; Liu, Zhen; Wen, Chao; Liu, Yang; Wang, Hong Zhe; Chen, T. P.; Zhang, Hai Yan

2018-06-01

With self-prepared nickel acetate based solution, NiO thin films with different thicknesses have been fabricated by spin coating followed by thermal annealing. By forming a two-terminal Ag/NiO/ITO structure on glass, write-once-read-many-times (WORM) memory devices are realized. The WORM memory behavior is based on a permanent switching from an initial high-resistance state (HRS) to an irreversible low-resistance state (LRS) under the application of a writing voltage, due to the formation of a solid bridge across Ag and ITO electrodes by conductive filaments (CFs). The memory performance is investigated as a function of the NiO film thickness, which is determined by the number of spin-coated NiO layers. For devices with 4 and 6 NiO layers, data retention up to 104 s and endurance of 103 reading operations in the measurement range have been obtained with memory window maintained above four orders for both HRS and LRS. Before and after writing, the devices show the hopping and ohmic conduction behaviors, respectively, confirming that the CF formation could be the mechanism responsible for writing in the WORM memory devices.

Hippocampal and ventral medial prefrontal activation during retrieval-mediated learning supports novel inference.

PubMed

Zeithamova, Dagmar; Dominick, April L; Preston, Alison R

2012-07-12

Memory enables flexible use of past experience to inform new behaviors. Although leading theories hypothesize that this fundamental flexibility results from the formation of integrated memory networks relating multiple experiences, the neural mechanisms that support memory integration are not well understood. Here, we demonstrate that retrieval-mediated learning, whereby prior event details are reinstated during encoding of related experiences, supports participants' ability to infer relationships between distinct events that share content. Furthermore, we show that activation changes in a functionally coupled hippocampal and ventral medial prefrontal cortical circuit track the formation of integrated memories and successful inferential memory performance. These findings characterize the respective roles of these regions in retrieval-mediated learning processes that support relational memory network formation and inferential memory in the human brain. More broadly, these data reveal fundamental mechanisms through which memory representations are constructed into prospectively useful formats. Copyright © 2012 Elsevier Inc. All rights reserved.

Hippocampal and ventral medial prefrontal activation during retrieval-mediated learning supports novel inference

PubMed Central

Zeithamova, Dagmar; Dominick, April L.; Preston, Alison R.

2012-01-01

SUMMARY Memory enables flexible use of past experience to inform new behaviors. Though leading theories hypothesize that this fundamental flexibility results from the formation of integrated memory networks relating multiple experiences, the neural mechanisms that support memory integration are not well understood. Here, we demonstrate that retrieval-mediated learning, whereby prior event details are reinstated during encoding of related experiences, supports participants’ ability to infer relationships between distinct events that share content. Furthermore, we show that activation changes in a functionally coupled hippocampal and ventral medial prefrontal cortical circuit track the formation of integrated memories and successful inferential memory performance. These findings characterize the respective roles of these regions in retrieval-mediated learning processes that support relational memory network formation and inferential memory in the human brain. More broadly, these data reveal fundamental mechanisms through which memory representations are constructed into prospectively useful formats. PMID:22794270

Behavioral interventions to eliminate fear responses.

PubMed

Yue, Jingli; Shi, Le; Lin, Xiao; Khan, Muhammad Zahid; Shi, Jie; Lu, Lin

2018-05-07

Fear memory underlies anxiety-related disorders, including posttraumatic stress disorder (PTSD). PTSD is a fear-based disorder, characterized by difficulties in extinguishing the learned fear response and maintaining extinction. Currently, the first-line treatment for PTSD is exposure therapy, which forms an extinction memory to compete with the original fear memory. However, the extinguished fear often returns under numerous circumstances, suggesting that novel methods are needed to eliminate fear memory or facilitate extinction memory. This review discusses research that targeted extinction and reconsolidation to manipulate fear memory. Recent studies indicate that sleep is an active state that can regulate memory processes. We also discuss the influence of sleep on fear memory. For each manipulation, we briefly summarize the neural mechanisms that have been identified in human studies. Finally, we highlight potential limitations and future directions in the field to better translate existing interventions to clinical settings.

Sleep-Dependent Consolidation of Rewarded Behavior Is Diminished in Children with Attention Deficit Hyperactivity Disorder and a Comorbid Disorder of Social Behavior

PubMed Central

Wiesner, Christian D.; Molzow, Ina; Prehn-Kristensen, Alexander; Baving, Lioba

2017-01-01

Children suffering from attention-deficit hyperactivity disorder (ADHD) often also display impaired learning and memory. Previous research has documented aberrant reward processing in ADHD as well as impaired sleep-dependent consolidation of declarative memory. We investigated whether sleep also fosters the consolidation of behavior learned by probabilistic reward and whether ADHD patients with a comorbid disorder of social behavior show deficits in this memory domain, too. A group of 17 ADHD patients with comorbid disorders of social behavior aged 8–12 years and healthy controls matched for age, IQ, and handedness took part in the experiment. During the encoding task, children worked on a probabilistic learning task acquiring behavioral preferences for stimuli rewarded most often. After a 12-hr retention interval of either sleep at night or wakefulness during the day, a reversal task was presented where the contingencies were reversed. Consolidation of rewarded behavior is indicated by greater resistance to reversal learning. We found that healthy children consolidate rewarded behavior better during a night of sleep than during a day awake and that the sleep-dependent consolidation of rewarded behavior by trend correlates with non-REM sleep but not with REM sleep. In contrast, children with ADHD and comorbid disorders of social behavior do not show sleep-dependent consolidation of rewarded behavior. Moreover, their consolidation of rewarded behavior does not correlate with sleep. The results indicate that dysfunctional sleep in children suffering from ADHD and disorders of social behavior might be a crucial factor in the consolidation of behavior learned by reward. PMID:28228742

Weekend Ecstasy use disrupts memory in rats

PubMed Central

McAleer, Leah M.; Schallert, Timothy; Duvauchelle, Christine L.

2013-01-01

3,4-Methylenedioxymethamphetamine (MDMA, or “Ecstasy”) is a popular recreational drug. However, its exposure is often limited to the weekends in a highly stimulating environment. The goal of this study was to investigate the behavioral domains of working and recognition memory within a model of “weekend” Ecstasy use. Rats self-administered MDMA during 2-hr sessions on two consecutive days followed by five drug-free days. Coupling this intermittent dosing schedule with a novel object recognition task, we found non-spatial memory impaired after only two “weekends” of self-administered MDMA. Our findings suggest that MDMA at recreational use levels can disrupt memory processes. PMID:23707649

Phospholipase A₂: the key to reversing long-term memory impairment in a gastropod model of aging.

PubMed

Watson, Shawn N; Wright, Natasha; Hermann, Petra M; Wildering, Willem C

2013-02-01

Memory failure associated with changes in neuronal circuit functions rather than cell death is a common feature of normal aging in diverse animal species. The (neuro)biological foundations of this phenomenon are not well understood although oxidative stress, particularly in the guise of lipid peroxidation, is suspected to play a key role. Using an invertebrate model system of age-associated memory impairment that supports direct correlation between behavioral deficits and changes in the underlying neural substrate, we show that inhibition of phospholipase A(2) (PLA(2)) abolishes both long-term memory (LTM) and neural defects observed in senescent subjects and subjects exposed to experimental oxidative stress. Using a combination of behavioral assessments and electrophysiological techniques, we provide evidence for a close link between lipid peroxidation, provocation of phospholipase A(2)-dependent free fatty acid release, decline of neuronal excitability, and age-related long-term memory impairments. This supports the view that these processes suspend rather than irreversibly extinguish the aging nervous system's intrinsic capacity for plasticity. Copyright © 2013 Elsevier Inc. All rights reserved.

Thermomechanical Analysis of Shape-Memory Composite Tape Spring

NASA Astrophysics Data System (ADS)

Yang, H.; Wang, L. Y.

2013-06-01

Intelligent materials and structures have been extensively applied for satellite designs in order to minimize the mass and reduce the cost in the launch of the spacecraft. Elastic memory composites (EMCs) have the ability of high-strain packaging and shape-memory effect, but increase the parts and total weight due to the additional heating system. Shape-memory sandwich structures Li and Wang (J. Intell. Mater. Syst. Struct. 22(14), 1605-1612, 2011) can overcome such disadvantage by using the metal skin acting as the heating element. However, the high strain in the micro-buckled metal skin decreases the deployment efficiency. This paper aims to present an insight into the folding and deployment behaviors of shape-memory composite (SMC) tape springs. A thermomechanical process was analyzed, including the packaging deformation at an elevated temperature, shape frozen at the low temperature and shape recovery after reheating. The result shows that SMC tape springs can significantly decrease the strain concentration in the metal skin, as well as exhibiting excellent shape frozen and recovery behaviors. Additionally, possible failure modes of SMC tape springs were also analyzed.

Multistate storage nonvolatile memory device based on ferroelectricity and resistive switching effects of SrBi2Ta2O9 films

NASA Astrophysics Data System (ADS)

Song, Zhiwei; Li, Gang; Xiong, Ying; Cheng, Chuanpin; Zhang, Wanli; Tang, Minghua; Li, Zheng; He, Jiangheng

2018-05-01

A memory device with a Pt/SrBi2Ta2O9(SBT)/Pt(111) structure was shown to have excellent combined ferroelectricity and resistive switching properties, leading to higher multistate storage memory capacity in contrast to ferroelectric memory devices. In this device, SBT polycrystalline thin films with significant (115) orientation were fabricated on Pt(111)/Ti/SiO2/Si(100) substrates using CVD (chemical vapor deposition) method. Measurement results of the electric properties exhibit reproducible and reliable ferroelectricity switching behavior and bipolar resistive switching effects (BRS) without an electroforming process. The ON/OFF ratio of the resistive switching was found to be about 103. Switching mechanisms for the low resistance state (LRS) and high resistance state (HRS) currents are likely attributed to the Ohmic and space charge-limited current (SCLC) behavior, respectively. Moreover, the ferroelectricity and resistive switching effects were found to be mutually independent, and the four logic states were obtained by controlling the periodic sweeping voltage. This work holds great promise for nonvolatile multistate memory devices with high capacity and low cost.

Biaxial Fatigue Behavior of Niti Shape Memory Alloy

DTIC Science & Technology

2005-03-01

BIAXIAL FATIGUE BEHAVIOR OF NiTi SHAPE MEMORY ALLOY THESIS Daniel M. Jensen, 1st Lieutenant...BIAXIAL FATIGUE BEHAVIOR OF NiTi SHAPE MEMORY ALLOY THESIS Presented to the Faculty Department of Aeronautics and Astronautics Graduate School of...FOR PUBLIC RELEASE; DISTRIBUTION UNLIMITED AFIT/GA/ENY/05-M06 BIAXIAL FATIGUE BEHAVIOR OF NiTi SHAPE MEMORY ALLOY Daniel M. Jensen

Reward modulation of hippocampal subfield activation during successful associative encoding and retrieval

PubMed Central

Wolosin, Sasha M.; Zeithamova, Dagmar; Preston, Alison R.

2012-01-01

Emerging evidence suggests that motivation enhances episodic memory formation through interactions between medial temporal lobe (MTL) structures and dopaminergic midbrain. In addition, recent theories propose that motivation specifically facilitates hippocampal associative binding processes, resulting in more detailed memories that are readily reinstated from partial input. Here, we used high-resolution functional magnetic resonance imaging to determine how motivation influences associative encoding and retrieval processes within human MTL subregions and dopaminergic midbrain. Participants intentionally encoded object associations under varying conditions of reward and performed a retrieval task during which studied associations were cued from partial input. Behaviorally, cued recall performance was superior for high-value relative to low-value associations; however, participants differed in the degree to which rewards influenced memory. The magnitude of behavioral reward modulation was associated with reward-related activation changes in dentate gyrus/CA2,3 during encoding and enhanced functional connectivity between dentate gyrus/CA2,3 and dopaminergic midbrain during both the encoding and retrieval phases of the task. These findings suggests that within the hippocampus, reward-based motivation specifically enhances dentate gyrus/CA2,3 associative encoding mechanisms through interactions with dopaminergic midbrain. Furthermore, within parahippocampal cortex and dopaminergic midbrain regions, activation associated with successful memory formation was modulated by reward across the group. During the retrieval phase, we also observed enhanced activation in hippocampus and dopaminergic midbrain for high-value associations that occurred in the absence of any explicit cues to reward. Collectively, these findings shed light on fundamental mechanisms through which reward impacts associative memory formation and retrieval through facilitation of MTL and VTA/SN processing. PMID:22524296

Selective attention on representations in working memory: cognitive and neural mechanisms.

PubMed

Ku, Yixuan

2018-01-01

Selective attention and working memory are inter-dependent core cognitive functions. It is critical to allocate attention on selected targets during the capacity-limited working memory processes to fulfill the goal-directed behavior. The trends of research on both topics are increasing exponentially in recent years, and it is considered that selective attention and working memory share similar underlying neural mechanisms. Different types of attention orientation in working memory are introduced by distinctive cues, and the means using retrospective cues are strengthened currently as it is manipulating the representation in memory, instead of the perceptual representation. The cognitive and neural mechanisms of the retro-cue effects are further reviewed, as well as the potential molecular mechanism. The frontal-parietal network that is involved in both attention and working memory is also the neural candidate for attention orientation during working memory. Neural oscillations in the gamma and alpha/beta oscillations may respectively be employed for the feedforward and feedback information transfer between the sensory cortices and the association cortices. Dopamine and serotonin systems might interact with each other subserving the communication between memory and attention. In conclusion, representations which attention shifts towards are strengthened, while representations which attention moves away from are degraded. Studies on attention orientation during working memory indicates the flexibility of the processes of working memory, and the beneficial way that overcome the limited capacity of working memory.

Selective attention on representations in working memory: cognitive and neural mechanisms

PubMed Central

2018-01-01

Selective attention and working memory are inter-dependent core cognitive functions. It is critical to allocate attention on selected targets during the capacity-limited working memory processes to fulfill the goal-directed behavior. The trends of research on both topics are increasing exponentially in recent years, and it is considered that selective attention and working memory share similar underlying neural mechanisms. Different types of attention orientation in working memory are introduced by distinctive cues, and the means using retrospective cues are strengthened currently as it is manipulating the representation in memory, instead of the perceptual representation. The cognitive and neural mechanisms of the retro-cue effects are further reviewed, as well as the potential molecular mechanism. The frontal-parietal network that is involved in both attention and working memory is also the neural candidate for attention orientation during working memory. Neural oscillations in the gamma and alpha/beta oscillations may respectively be employed for the feedforward and feedback information transfer between the sensory cortices and the association cortices. Dopamine and serotonin systems might interact with each other subserving the communication between memory and attention. In conclusion, representations which attention shifts towards are strengthened, while representations which attention moves away from are degraded. Studies on attention orientation during working memory indicates the flexibility of the processes of working memory, and the beneficial way that overcome the limited capacity of working memory. PMID:29629245

Deficits in episodic memory are related to uncontrolled eating in a sample of healthy adults.

PubMed

Martin, A A; Davidson, T L; McCrory, M A

2018-05-01

Despite a substantial amount of animal data linking deficits in memory inhibition to the development of overeating and obesity, few studies have investigated the relevance of memory inhibition to uncontrolled eating in humans. Further, although memory for recent eating has been implicated as an important contributor to satiety and energy intake, the possibility that variations in episodic memory relate to individual differences in food intake control has been largely neglected. To examine these relationships, we recruited ninety-three adult subjects to attend a single lab session where we assessed body composition, dietary intake, memory performance, and eating behaviors (Three Factor Eating Questionnaire). Episodic recall and memory inhibition were assessed using a well-established measure of memory interference (Retrieval Practice Paradigm). Hierarchical regression analyses indicated that memory inhibition was largely unrelated to participants' eating behaviors; however, episodic recall was reliably predicted by restrained vs. uncontrolled eating: recall was positively associated with strategic dieting (β = 2.45, p = 0.02), avoidance of fatty foods (β = 3.41, p = 0.004), and cognitive restraint (β = 1.55, p = 0.04). In contrast, recall was negatively associated with uncontrolled eating (β = -1.15, p = 0.03) and emotional eating (β = -2.46, p = 0.04). These findings suggest that episodic memory processing is related to uncontrolled eating in humans. The possibility that deficits in episodic memory may contribute to uncontrolled eating by disrupting memory for recent eating is discussed. Copyright © 2017 Elsevier Ltd. All rights reserved.

Dissociation between controlled and automatic processes in the behavioral variant of fronto-temporal dementia.

PubMed

Collette, Fabienne; Van der Linden, Martial; Salmon, Eric

2010-01-01

A decline of cognitive functioning affecting several cognitive domains was frequently reported in patients with frontotemporal dementia. We were interested in determining if these deficits can be interpreted as reflecting an impairment of controlled cognitive processes by using an assessment tool specifically developed to explore the distinction between automatic and controlled processes, namely the process dissociation procedure (PDP) developed by Jacoby. The PDP was applied to a word stem completion task to determine the contribution of automatic and controlled processes to episodic memory performance and was administered to a group of 12 patients with the behavioral variant of frontotemporal dementia (bv-FTD) and 20 control subjects (CS). Bv-FTD patients obtained a lower performance than CS for the estimates of controlled processes, but no group differences was observed for estimates of automatic processes. The between-groups comparison of the estimates of controlled and automatic processes showed a larger contribution of automatic processes to performance in bv-FTD, while a slightly more important contribution of controlled processes was observed in control subjects. These results are clearly indicative of an alteration of controlled memory processes in bv-FTD.

Non-singleton colors are not attended faster than categories, but they are encoded faster: A combined approach of behavior, modeling and ERPs.

PubMed

Callahan-Flintoft, Chloe; Wyble, Brad

2017-11-01

The visual system is able to detect targets according to a variety of criteria, such as by categorical (letter vs digit) or featural attributes (color). These criteria are often used interchangeably in rapid serial visual presentation (RSVP) studies but little is known about how rapidly they are processed. The aim of this work was to compare the time course of attentional selection and memory encoding for different types of target criteria. We conducted two experiments where participants reported one or two targets (T1, T2) presented in lateral RSVP streams. Targets were marked either by being a singleton color (red letter among black letters), being categorically distinct (digits among letters) or non-singleton color (target color letter among heterogeneously colored letters). Using event related potential (ERPs) associated with attention and memory encoding (the N2pc and the P3 respectively), we compared the relative latency of these two processing stages for these three kinds of targets. In addition to these ERP measures, we obtained convergent behavioral measures for attention and memory encoding by presenting two targets in immediate sequence and comparing their relative accuracy and proportion of temporal order errors. Both behavioral and EEG measures revealed that singleton color targets were attended much more quickly than either non-singleton color or categorical targets, and there was very little difference between attention latencies to non-singleton color and categorical targets. There was however a difference in the speed of memory encoding for non-singleton color and category latencies in both behavioral and EEG measures, which shows that encoding latency differences do not always mirror attention latency differences. Copyright © 2017 Elsevier Ltd. All rights reserved.

The role of replay and theta sequences in mediating hippocampal-prefrontal interactions for memory and cognition.

PubMed

Zielinski, Mark C; Tang, Wenbo; Jadhav, Shantanu P

2017-12-18

Sequential activity is seen in the hippocampus during multiple network patterns, prominently as replay activity during both awake and sleep sharp-wave ripples (SWRs), and as theta sequences during active exploration. Although various mnemonic and cognitive functions have been ascribed to these hippocampal sequences, evidence for these proposed functions remains primarily phenomenological. Here, we briefly review current knowledge about replay events and theta sequences in spatial memory tasks. We reason that in order to gain a mechanistic and causal understanding of how these patterns influence memory and cognitive processing, it is important to consider how these sequences influence activity in other regions, and in particular, the prefrontal cortex, which is crucial for memory-guided behavior. For spatial memory tasks, we posit that hippocampal-prefrontal interactions mediated by replay and theta sequences play complementary and overlapping roles at different stages in learning, supporting memory encoding and retrieval, deliberative decision making, planning, and guiding future actions. This framework offers testable predictions for future physiology and closed-loop feedback inactivation experiments for specifically targeting hippocampal sequences as well as coordinated prefrontal activity in different network states, with the potential to reveal their causal roles in memory-guided behavior. © 2017 Wiley Periodicals, Inc.

Work and information processing in a solvable model of Maxwell's demon.

PubMed

Mandal, Dibyendu; Jarzynski, Christopher

2012-07-17

We describe a minimal model of an autonomous Maxwell demon, a device that delivers work by rectifying thermal fluctuations while simultaneously writing information to a memory register. We solve exactly for the steady-state behavior of our model, and we construct its phase diagram. We find that our device can also act as a "Landauer eraser", using externally supplied work to remove information from the memory register. By exposing an explicit, transparent mechanism of operation, our model offers a simple paradigm for investigating the thermodynamics of information processing by small systems.

Empirical modeling of an alcohol expectancy memory network using multidimensional scaling.

PubMed

Rather, B C; Goldman, M S; Roehrich, L; Brannick, M

1992-02-01

Risk-related antecedent variables can be linked to later alcohol consumption by memory processes, and alcohol expectancies may be one relevant memory content. To advance research in this area, it would be useful to apply current memory models such as semantic network theory to explain drinking decision processes. We used multidimensional scaling (MDS) to empirically model a preliminary alcohol expectancy semantic network, from which a theoretical account of drinking decision making was generated. Subanalyses (PREFMAP) showed how individuals with differing alcohol consumption histories may have had different association pathways within the expectancy network. These pathways may have, in turn influenced future drinking levels and behaviors while the person was under the influence of alcohol. All individuals associated positive/prosocial effects with drinking, but heavier drinkers indicated arousing effects as their highest probability associates, whereas light drinkers expected sedation. An important early step in this MDS modeling process is the determination of iso-meaning expectancy adjective groups, which correspond to theoretical network nodes.

Activation of ERK2 in basolateral amygdala underlies the promoting influence of stress on fear memory and anxiety: influence of midazolam pretreatment.

PubMed

Maldonado, N M; Espejo, P J; Martijena, I D; Molina, V A

2014-02-01

Exposure to emotionally arousing experiences elicits a robust and persistent memory and enhances anxiety. The amygdala complex plays a key role in stress-induced emotional processing and in the fear memory formation. It is well known that ERK activation in the amygdala is a prerequisite for fear memory consolidation. Moreover, stress elevates p-ERK2 levels in several areas of the brain stress circuitry. Therefore, given that the ERK1/2 cascade is activated following stress and that the role of this cascade is critical in the formation of fear memory, the present study investigated the potential involvement of p-ERK2 in amygdala subnuclei in the promoting influence of stress on fear memory formation and on anxiety-like behavior. A robust and persistent ERK2 activation was noted in the Basolateral amygdala (BLA), which was evident at 5min after restraint and lasted at least one day after the stressful experience. Midazolam, a short-acting benzodiazepine ligand, administered prior to stress prevented the increase in the p-ERK2 level in the BLA. Pretreatment with intra-BLA infusion of U0126 (MEK inhibitor), but not into the adjacent central nucleus of the amygdala, attenuated the stress-induced promoting influence on fear memory formation. Finally, U0126 intra-BLA infusion prevented the enhancement of anxiety-like behavior in stressed animals. These findings suggest that the selective ERK2 activation in BLA following stress exposure is an important mechanism for the occurrence of the promoting influence of stress on fear memory and on anxiety-like behavior. © 2013 Published by Elsevier B.V. and ECNP.

Heuristic Processes in Ratings of Leader Behavior: Assessing Item-Induced Availability Biases.

ERIC Educational Resources Information Center

Binning, John F.; Fernandez, Guadalupe

Since observers' memory-based ratings of organizational phenomena provide data in research and decision-making contexts, bias in observers' judgments must be examined. A study was conducted to explore the extent to which leader behavior ratings are more generally biased by the availability heuristic. The availability heuristic is operative when a…

The Electrophysiological Signature of Remember-Know Is Confounded with Memory Strength and Cannot Be Interpreted as Evidence for Dual-process Theory of Recognition.

PubMed

Brezis, Noam; Bronfman, Zohar Z; Yovel, Galit; Goshen-Gottstein, Yonatan

2017-02-01

The quantity and nature of the processes underlying recognition memory remains an open question. A majority of behavioral, neuropsychological, and brain studies have suggested that recognition memory is supported by two dissociable processes: recollection and familiarity. It has been conversely argued, however, that recollection and familiarity map onto a single continuum of mnemonic strength and hence that recognition memory is mediated by a single process. Previous electrophysiological studies found marked dissociations between recollection and familiarity, which have been widely held as corroborating the dual-process account. However, it remains unknown whether a strength interpretation can likewise apply for these findings. Here we describe an ERP study, using a modified remember-know (RK) procedure, which allowed us to control for mnemonic strength. We find that ERPs of high and low mnemonic strength mimicked the electrophysiological distinction between R and K responses, in a lateral positive component (LPC), 500-1000 msec poststimulus onset. Critically, when contrasting strength with RK experience, by comparing weak R to strong K responses, the electrophysiological signal mapped onto strength, not onto subjective RK experience. Invoking the LPC as support for dual-process accounts may, therefore, be amiss.

Memory Effects of Benzodiazepines: Memory Stages and Types Versus Binding-Site Subtypes

PubMed Central

Savić, Miroslav M.; Obradović, Dragan I.; Ugrešić, Nenad D.; Bokonjić, Dubravko R.

2005-01-01

Benzodiazepines are well established as inhibitory modulators of memory processing. This effect is especially prominent when applied before the acquisition phase of a memory task. This minireview concentrates on the putative subtype selectivity of the acquisition-impairing action of benzodiazepines. Namely, recent genetic studies and standard behavioral tests employing subtype-selective ligands pointed to the predominant involvement of two subtypes of benzodiazepine binding sites in memory modulation. Explicit memory learning seems to be affected through the GABAA receptors containing the α1 and α1 subunits, whereas the effects on procedural memory can be mainly mediated by the α1 subunit. The pervading involvement of the α1 subunit in memory modulation is not at all unexpected because this subunit is the major subtype, present in 60% of all GABAA receptors. On the other hand, the role of α5 subunits, mainly expressed in the hippocampus, in modulating distinct forms of memory gives promise of selective pharmacological coping with certain memory deficit states. PMID:16444900

The relationship between loss of parents in the holocaust, intrusive memories, and distress among child survivors.

PubMed

Letzter-Pouw, Sonia; Werner, Perla

2012-04-01

The prevalence of intrusive memories of the Holocaust and their relationship to distress was examined among 272 child survivors in Israel. Using attachment theory as a conceptual framework, the authors also examined the effects of type of experience and loss of parents in the Holocaust, psychological resources, other life events, and sociodemographic characteristics on distress and symptomatic behavior. Eighty five percent of the participants reported suffering from intrusive memories. Structural equation modeling showed that survivors who lost one or both parents in the Holocaust suffered more distress because of more intrusive memories. These findings suggest that intrusive memories may be part of unfinished mourning processes related to the loss of parents in the Holocaust. © 2012 American Orthopsychiatric Association.

Postnatal Loss of Mef2c Results in Dissociation of Effects on Synapse Number and Learning and Memory.

PubMed

Adachi, Megumi; Lin, Pei-Yi; Pranav, Heena; Monteggia, Lisa M

2016-07-15

Myocyte enhancer factor 2 (MEF2) transcription factors play critical roles in diverse cellular processes during central nervous system development. Studies attempting to address the role of MEF2 in brain have largely relied on overexpression of a constitutive MEF2 construct that impairs memory formation or knockdown of MEF2 function that increases spine numbers and enhances memory formation. Genetic deletion of individual MEF2 isoforms in brain during embryogenesis demonstrated that Mef2c loss negatively regulates spine numbers resulting in learning and memory deficits, possibly as a result of its essential role in development. To investigate MEF2C function in brain further, we genetically deleted Mef2c during postnatal development in mice. We characterized these conditional Mef2c knockout mice in an array of behavioral paradigms and examined the impact of postnatal loss of Mef2c on long-term potentiation. We observed increased spine numbers in hippocampus of the conditional Mef2c knockout mice. However, the postnatal loss of Mef2c did not impact learning and memory, long-term potentiation, or social and repetitive behaviors. Our findings demonstrate a critical role for MEF2C in the regulation of spine numbers with a dissociation of learning and memory, synaptic plasticity, and measures of autism-related behaviors in postnatal brain. Copyright © 2016 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

Memory-Relevant Mushroom Body Output Synapses Are Cholinergic.

PubMed

Barnstedt, Oliver; Owald, David; Felsenberg, Johannes; Brain, Ruth; Moszynski, John-Paul; Talbot, Clifford B; Perrat, Paola N; Waddell, Scott

2016-03-16

Memories are stored in the fan-out fan-in neural architectures of the mammalian cerebellum and hippocampus and the insect mushroom bodies. However, whereas key plasticity occurs at glutamatergic synapses in mammals, the neurochemistry of the memory-storing mushroom body Kenyon cell output synapses is unknown. Here we demonstrate a role for acetylcholine (ACh) in Drosophila. Kenyon cells express the ACh-processing proteins ChAT and VAChT, and reducing their expression impairs learned olfactory-driven behavior. Local ACh application, or direct Kenyon cell activation, evokes activity in mushroom body output neurons (MBONs). MBON activation depends on VAChT expression in Kenyon cells and is blocked by ACh receptor antagonism. Furthermore, reducing nicotinic ACh receptor subunit expression in MBONs compromises odor-evoked activation and redirects odor-driven behavior. Lastly, peptidergic corelease enhances ACh-evoked responses in MBONs, suggesting an interaction between the fast- and slow-acting transmitters. Therefore, olfactory memories in Drosophila are likely stored as plasticity of cholinergic synapses. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Weighted integration of short-term memory and sensory signals in the oculomotor system.

PubMed

Deravet, Nicolas; Blohm, Gunnar; de Xivry, Jean-Jacques Orban; Lefèvre, Philippe

2018-05-01

Oculomotor behaviors integrate sensory and prior information to overcome sensory-motor delays and noise. After much debate about this process, reliability-based integration has recently been proposed and several models of smooth pursuit now include recurrent Bayesian integration or Kalman filtering. However, there is a lack of behavioral evidence in humans supporting these theoretical predictions. Here, we independently manipulated the reliability of visual and prior information in a smooth pursuit task. Our results show that both smooth pursuit eye velocity and catch-up saccade amplitude were modulated by visual and prior information reliability. We interpret these findings as the continuous reliability-based integration of a short-term memory of target motion with visual information, which support modeling work. Furthermore, we suggest that saccadic and pursuit systems share this short-term memory. We propose that this short-term memory of target motion is quickly built and continuously updated, and constitutes a general building block present in all sensorimotor systems.

Signal and noise extraction from analog memory elements for neuromorphic computing.

PubMed

Gong, N; Idé, T; Kim, S; Boybat, I; Sebastian, A; Narayanan, V; Ando, T

2018-05-29

Dense crossbar arrays of non-volatile memory (NVM) can potentially enable massively parallel and highly energy-efficient neuromorphic computing systems. The key requirements for the NVM elements are continuous (analog-like) conductance tuning capability and switching symmetry with acceptable noise levels. However, most NVM devices show non-linear and asymmetric switching behaviors. Such non-linear behaviors render separation of signal and noise extremely difficult with conventional characterization techniques. In this study, we establish a practical methodology based on Gaussian process regression to address this issue. The methodology is agnostic to switching mechanisms and applicable to various NVM devices. We show tradeoff between switching symmetry and signal-to-noise ratio for HfO 2 -based resistive random access memory. Then, we characterize 1000 phase-change memory devices based on Ge 2 Sb 2 Te 5 and separate total variability into device-to-device variability and inherent randomness from individual devices. These results highlight the usefulness of our methodology to realize ideal NVM devices for neuromorphic computing.

Thermodynamic framework for information in nanoscale systems with memory

NASA Astrophysics Data System (ADS)

Arias-Gonzalez, J. Ricardo

2017-11-01

Information is represented by linear strings of symbols with memory that carry errors as a result of their stochastic nature. Proofreading and edition are assumed to improve certainty although such processes may not be effective. Here, we develop a thermodynamic theory for material chains made up of nanoscopic subunits with symbolic meaning in the presence of memory. This framework is based on the characterization of single sequences of symbols constructed under a protocol and is used to derive the behavior of ensembles of sequences similarly constructed. We then analyze the role of proofreading and edition in the presence of memory finding conditions to make revision an effective process, namely, to decrease the entropy of the chain. Finally, we apply our formalism to DNA replication and RNA transcription finding that Watson and Crick hybridization energies with which nucleotides are branched to the template strand during the copying process are optimal to regulate the fidelity in proofreading. These results are important in applications of information theory to a variety of solid-state physical systems and other biomolecular processes.

Thermodynamic framework for information in nanoscale systems with memory.

PubMed

Arias-Gonzalez, J Ricardo

2017-11-28

Information is represented by linear strings of symbols with memory that carry errors as a result of their stochastic nature. Proofreading and edition are assumed to improve certainty although such processes may not be effective. Here, we develop a thermodynamic theory for material chains made up of nanoscopic subunits with symbolic meaning in the presence of memory. This framework is based on the characterization of single sequences of symbols constructed under a protocol and is used to derive the behavior of ensembles of sequences similarly constructed. We then analyze the role of proofreading and edition in the presence of memory finding conditions to make revision an effective process, namely, to decrease the entropy of the chain. Finally, we apply our formalism to DNA replication and RNA transcription finding that Watson and Crick hybridization energies with which nucleotides are branched to the template strand during the copying process are optimal to regulate the fidelity in proofreading. These results are important in applications of information theory to a variety of solid-state physical systems and other biomolecular processes.

The effects of long-term stress exposure on aging cognition: a behavioral and EEG investigation.

PubMed

Marshall, Amanda C; Cooper, Nicholas R; Segrave, Rebecca; Geeraert, Nicolas

2015-06-01

A large field of research seeks to explore and understand the factors that may cause different rates of age-related cognitive decline within the general population. However, the impact of experienced stress on the human aging process has remained an under-researched possibility. This study explored the association between cumulative stressful experiences and cognitive aging, addressing whether higher levels of experienced stress correlate with impaired performance on 2 working memory tasks. Behavioral performance was paired with electroencephalographic recordings to enable insight into the underlying neural processes impacted on by cumulative stress. Thus, the electroencephalogram was recorded while both young and elderly performed 2 different working memory tasks (a Sternberg and N-back paradigm), and cortical oscillatory activity in the theta, alpha, and gamma bandwidths was measured. Behavioral data indicated that a higher stress score among elderly participants related to impaired performance on both tasks. Electrophysiological findings revealed a reduction in alpha and gamma event-related synchronization among high-stress-group elderly participants, indicating that higher levels of experienced stress may impact on their ability to actively maintain a stimulus in working memory and inhibit extraneous information interfering with successful maintenance. Findings provide evidence that cumulative experienced stress adversely affects cognitive aging. Copyright © 2015 Elsevier Inc. All rights reserved.

Dopamine modulation of emotional processing in cortical and subcortical neural circuits: evidence for a final common pathway in schizophrenia?

PubMed

Laviolette, Steven R

2007-07-01

The neural regulation of emotional perception, learning, and memory is essential for normal behavioral and cognitive functioning. Many of the symptoms displayed by individuals with schizophrenia may arise from fundamental disturbances in the ability to accurately process emotionally salient sensory information. The neurotransmitter dopamine (DA) and its ability to modulate neural regions involved in emotional learning, perception, and memory formation has received considerable research attention as a potential final common pathway to account for the aberrant emotional regulation and psychosis present in the schizophrenic syndrome. Evidence from both human neuroimaging studies and animal-based research using neurodevelopmental, behavioral, and electrophysiological techniques have implicated the mesocorticolimbic DA circuit as a crucial system for the encoding and expression of emotionally salient learning and memory formation. While many theories have examined the cortical-subcortical interactions between prefrontal cortical regions and subcortical DA substrates, many questions remain as to how DA may control emotional perception and learning and how disturbances linked to DA abnormalities may underlie the disturbed emotional processing in schizophrenia. Beyond the mesolimbic DA system, increasing evidence points to the amygdala-prefrontal cortical circuit as an important processor of emotionally salient information and how neurodevelopmental perturbances within this circuitry may lead to dysregulation of DAergic modulation of emotional processing and learning along this cortical-subcortical emotional processing circuit.

Network-wide reorganization of procedural memory during NREM sleep revealed by fMRI

PubMed Central

Vahdat, Shahabeddin; Fogel, Stuart; Benali, Habib; Doyon, Julien

2017-01-01

Sleep is necessary for the optimal consolidation of newly acquired procedural memories. However, the mechanisms by which motor memory traces develop during sleep remain controversial in humans, as this process has been mainly investigated indirectly by comparing pre- and post-sleep conditions. Here, we used functional magnetic resonance imaging and electroencephalography during sleep following motor sequence learning to investigate how newly-formed memory traces evolve dynamically over time. We provide direct evidence for transient reactivation followed by downscaling of functional connectivity in a cortically-dominant pattern formed during learning, as well as gradual reorganization of this representation toward a subcortically-dominant consolidated trace during non-rapid eye movement (NREM) sleep. Importantly, the putamen functional connectivity within the consolidated network during NREM sleep was related to overnight behavioral gains. Our results demonstrate that NREM sleep is necessary for two complementary processes: the restoration and reorganization of newly-learned information during sleep, which underlie human motor memory consolidation. DOI: http://dx.doi.org/10.7554/eLife.24987.001 PMID:28892464

Activation of alpha2 adrenergic receptors suppresses fear conditioning: expression of c-Fos and phosphorylated CREB in mouse amygdala.

PubMed

Davies, M Frances; Tsui, Janet; Flannery, Judy A; Li, Xiangqi; DeLorey, Timothy M; Hoffman, Brian B

2004-02-01

alpha(2) adrenergic agonists such as dexmedetomidine generally suppress noradrenergic transmission and have sedative, analgesic, and antihypertensive properties. Considering the importance of the neurotransmitter norepinephrine in forming memories for fearful events, we have investigated the acute and chronic effects of dexmedetomidine on discrete cue and contextual fear conditioning in mice. When administered before training, dexmedetomidine (10-20 microg/kg, i.p.) selectively suppressed discrete cue fear conditioning without affecting contextual memory. This behavioral change was associated with a decrease in memory retrieval-induced expression of c-Fos and P-CREB in the lateral, basolateral, and central nuclei of the amygdala. Dexmedetomidine's action on discrete cue memory did not occur in alpha(2A) adrenoceptor knockout (KO) mice. When dexmedetomidine was administered after training, it suppressed contextual memory, an effect that did not occur in alpha(2A) adrenoceptor KO mice. We conclude that dexmedetomidine, acting at alpha(2A) adrenoceptors, must be present during the encoding process to decrease discrete cue fear memory; however, its ability to suppress contextual memory is likely the result of blocking the consolidation process. The ability of alpha(2) agonists to suppress fear memory may be a valuable property clinically in order to suppress the formation of memories during stressful situations.

Old-new ERP effects and remote memories: the late parietal effect is absent as recollection fails whereas the early mid-frontal effect persists as familiarity is retained

PubMed Central

Tsivilis, Dimitris; Allan, Kevin; Roberts, Jenna; Williams, Nicola; Downes, John Joseph; El-Deredy, Wael

2015-01-01

Understanding the electrophysiological correlates of recognition memory processes has been a focus of research in recent years. This study investigated the effects of retention interval on recognition memory by comparing memory for objects encoded four weeks (remote) or 5 min (recent) before testing. In Experiment 1, event related potentials (ERPs) were acquired while participants performed a yes-no recognition memory task involving remote, recent and novel objects. Relative to correctly rejected new items, remote and recent hits showed an attenuated frontal negativity from 300–500 ms post-stimulus. This effect, also known as the FN400, has been previously associated with familiarity memory. Recent and remote recognition ERPs did not differ from each other at this time-window. By contrast, recent but not remote recognition showed increased parietal positivity from around 500 ms post-stimulus. This late parietal effect (LPE), which is considered a correlate of recollection-related processes, also discriminated between recent and remote memories. A second, behavioral experiment confirmed that remote memories unlike recent memories were based almost exclusively on familiarity. These findings support the idea that the FN400 and LPE are indices of familiarity and recollection memory, respectively and show that remote and recent memories are functionally and anatomically distinct. PMID:26528163

Externally induced frontoparietal synchronization modulates network dynamics and enhances working memory performance.

PubMed

Violante, Ines R; Li, Lucia M; Carmichael, David W; Lorenz, Romy; Leech, Robert; Hampshire, Adam; Rothwell, John C; Sharp, David J

2017-03-14

Cognitive functions such as working memory (WM) are emergent properties of large-scale network interactions. Synchronisation of oscillatory activity might contribute to WM by enabling the coordination of long-range processes. However, causal evidence for the way oscillatory activity shapes network dynamics and behavior in humans is limited. Here we applied transcranial alternating current stimulation (tACS) to exogenously modulate oscillatory activity in a right frontoparietal network that supports WM. Externally induced synchronization improved performance when cognitive demands were high. Simultaneously collected fMRI data reveals tACS effects dependent on the relative phase of the stimulation and the internal cognitive processing state. Specifically, synchronous tACS during the verbal WM task increased parietal activity, which correlated with behavioral performance. Furthermore, functional connectivity results indicate that the relative phase of frontoparietal stimulation influences information flow within the WM network. Overall, our findings demonstrate a link between behavioral performance in a demanding WM task and large-scale brain synchronization.

Externally induced frontoparietal synchronization modulates network dynamics and enhances working memory performance

PubMed Central

Violante, Ines R; Li, Lucia M; Carmichael, David W; Lorenz, Romy; Leech, Robert; Hampshire, Adam; Rothwell, John C; Sharp, David J

2017-01-01

Cognitive functions such as working memory (WM) are emergent properties of large-scale network interactions. Synchronisation of oscillatory activity might contribute to WM by enabling the coordination of long-range processes. However, causal evidence for the way oscillatory activity shapes network dynamics and behavior in humans is limited. Here we applied transcranial alternating current stimulation (tACS) to exogenously modulate oscillatory activity in a right frontoparietal network that supports WM. Externally induced synchronization improved performance when cognitive demands were high. Simultaneously collected fMRI data reveals tACS effects dependent on the relative phase of the stimulation and the internal cognitive processing state. Specifically, synchronous tACS during the verbal WM task increased parietal activity, which correlated with behavioral performance. Furthermore, functional connectivity results indicate that the relative phase of frontoparietal stimulation influences information flow within the WM network. Overall, our findings demonstrate a link between behavioral performance in a demanding WM task and large-scale brain synchronization. DOI: http://dx.doi.org/10.7554/eLife.22001.001 PMID:28288700

The AIDS Memorial Quilt as preventative education: a developmental analysis of the Quilt.

PubMed

Knaus, C S; Austin, E W

1999-12-01

This study consisted of a survey given to college students (N = 560) at a rural university in the Pacific Northwest. The sample was randomly assigned into four groups, following the Solomon four-group study design. The two levels of treatment included interventions consisting of a visit to the AIDS Memorial Quilt for the experimental groups and attendance at an unrelated event for the control groups. Pretests were completed 4 weeks prior to interventions; posttests were completed by the entire sample 4 weeks after the interventions. Results confirmed expected differences among the four groups in terms of social distance, perceptions of people with AIDS, self-efficacy, and discussion of risky behavior. The results suggest that the AIDS Memorial Quilt addresses issues centrally related to behavior change and indicates support for the message interpretation process and stages of change models.

Dorsal hippocampal microinjection of chlorpheniramine reverses the anxiolytic-like effects of l-histidine and impairs emotional memory in mice.

PubMed

Canto-de-Souza, L; Garção, D C; Romaguera, F; Mattioli, R

2015-02-05

Several findings have pointed to the role of histaminergic neurotransmission in the modulation of anxiety-like behaviors and emotional memory. The elevated plus-maze (EPM) test has been widely used to investigate the process of anxiety and also has been used to investigate the process of learning and memory. Visual cues are relevant to the formation of spatial maps, and as the hippocampus is involved in this task, experiment 1 explored this issue. Experiment 2 investigated the effects of intraperitoneal (i.p.) injections of l-histidine (LH, a precursor of histamine) and of intra-dorsal hippocampus (intra-DH) injections of chlorpheniramine (CPA, an H1 receptor antagonist) on anxiety and emotional memory in mice re-exposed to the EPM. Mice received saline (SAL) or LH i.p. and SAL or CPA (0.016, 0.052, and 0.16 nmol/0.1 μl) intra-DH prior to Trial 1 (T1) and Trial 2 (T2). No significant changes were observed in the number of enclosed-arm entries (EAE) in T1, an EPM index of general exploratory activity. LH had an anxiolytic-like effect that was reversed by intra-DH injections of CPA. T2 versus T1 analysis revealed that only the lower dose of CPA resulted in impaired emotional memory. Combined injections of LH and CPA revealed that higher doses of CPA impair emotional memory. Taken together, these results suggest that LH and H1 receptors present in the dorsal hippocampus are involved in anxiety-related behaviors and emotional memory in mice submitted to EPM. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Characterization of origami shape memory metamaterials (SMMM) made of bio-polymer blends

NASA Astrophysics Data System (ADS)

Kshad, Mohamed Ali E.; Naguib, Hani E.

2016-04-01

Shape memory materials (SMMs) are materials that can return to their virgin state and release mechanically induced strains by external stimuli. Shape memory polymers (SMPs) are a class of SMMs that show a high shape recoverability and which have attractive potential for structural applications. In this paper, we experimentally study the shape memory effect of origami based metamaterials. The main focus is on the Muira origami metamaterials. The fabrication technique used to produce origami structure is direct molding where all the geometrical features are molded from thermally virgin polymers without post folding of flat sheets. The study shows experimental investigations of shape memory metamaterials (SMMMs) made of SMPs that can be used in different applications such as medicine, robotics, and lightweight structures. The origami structure made from SMP blends, activated with uniform heating. The effect of blend composition on the shape memory behavior was studied. Also the influence of the thermomechanical and the viscoelastic properties of origami unit cell on the activation process have been discussed, and stress relaxation and shape recovery were investigated. Activation process of the unit cell has been demonstrated.

Talker-specific learning in amnesia: Insight into mechanisms of adaptive speech perception.

PubMed

Trude, Alison M; Duff, Melissa C; Brown-Schmidt, Sarah

2014-05-01

A hallmark of human speech perception is the ability to comprehend speech quickly and effortlessly despite enormous variability across talkers. However, current theories of speech perception do not make specific claims about the memory mechanisms involved in this process. To examine whether declarative memory is necessary for talker-specific learning, we tested the ability of amnesic patients with severe declarative memory deficits to learn and distinguish the accents of two unfamiliar talkers by monitoring their eye-gaze as they followed spoken instructions. Analyses of the time-course of eye fixations showed that amnesic patients rapidly learned to distinguish these accents and tailored perceptual processes to the voice of each talker. These results demonstrate that declarative memory is not necessary for this ability and points to the involvement of non-declarative memory mechanisms. These results are consistent with findings that other social and accommodative behaviors are preserved in amnesia and contribute to our understanding of the interactions of multiple memory systems in the use and understanding of spoken language. Copyright © 2014 Elsevier Ltd. All rights reserved.

On the Evolution of Behaviors through Embodied Imitation.

PubMed

Erbas, Mehmet D; Bull, Larry; Winfield, Alan F T

2015-01-01

This article describes research in which embodied imitation and behavioral adaptation are investigated in collective robotics. We model social learning in artificial agents with real robots. The robots are able to observe and learn each others' movement patterns using their on-board sensors only, so that imitation is embodied. We show that the variations that arise from embodiment allow certain behaviors that are better adapted to the process of imitation to emerge and evolve during multiple cycles of imitation. As these behaviors are more robust to uncertainties in the real robots' sensors and actuators, they can be learned by other members of the collective with higher fidelity. Three different types of learned-behavior memory have been experimentally tested to investigate the effect of memory capacity on the evolution of movement patterns, and results show that as the movement patterns evolve through multiple cycles of imitation, selection, and variation, the robots are able to, in a sense, agree on the structure of the behaviors that are imitated.

A Key Role for Nectin-1 in the Ventral Hippocampus in Contextual Fear Memory

PubMed Central

Grosse, Jocelyn; Krummenacher, Claude; Sandi, Carmen

2013-01-01

Nectins are cell adhesion molecules that are widely expressed in the brain. Nectin expression shows a dynamic spatiotemporal regulation, playing a role in neural migratory processes during development. Nectin-1 and nectin-3 and their heterophilic trans-interactions are important for the proper formation of synapses. In the hippocampus, nectin-1 and nectin-3 localize at puncta adherentia junctions and may play a role in synaptic plasticity, a mechanism essential for memory and learning. We evaluated the potential involvement of nectin-1 and nectin-3 in memory consolidation using an emotional learning paradigm. Rats trained for contextual fear conditioning showed transient nectin-1—but not nectin-3—protein upregulation in synapse-enriched hippocampal fractions at about 2 h posttraining. The upregulation of nectin-1 was found exclusively in the ventral hippocampus and was apparent in the synaptoneurosomal fraction. This upregulation was induced by contextual fear conditioning but not by exposure to context or shock alone. When an antibody against nectin-1, R165, was infused in the ventral-hippocampus immediately after training, contextual fear memory was impaired. However, treatment with the antibody in the dorsal hippocampus had no effect in contextual fear memory formation. Similarly, treatment with the antibody in the ventral hippocampus did not interfere with acoustic memory formation. Further control experiments indicated that the effects of ventral hippocampal infusion of the nectin-1 antibody in contextual fear memory cannot be ascribed to memory non-specific effects such as changes in anxiety-like behavior or locomotor behavior. Therefore, we conclude that nectin-1 recruitment to the perisynaptic environment in the ventral hippocampus plays an important role in the formation of contextual fear memories. Our results suggest that these mechanisms could be involved in the connection of emotional and contextual information processed in the amygdala and dorsal hippocampus, respectively, thus opening new venues for the development of treatments to psychopathological alterations linked to impaired contextualization of emotions. PMID:23418609

Hippocampal SSTR4 somatostatin receptors control the selection of memory strategies.

PubMed

Gastambide, François; Viollet, Cécile; Lepousez, Gabriel; Epelbaum, Jacques; Guillou, Jean-Louis

2009-01-01

Somatostatin (SS14) has been implicated in various cognitive disorders, and converging evidence from animal studies suggests that SS14 neurons differentially regulate hippocampal- and striatal-dependent memory formation. Four SS14 receptor subtypes (SSTR1-4) are expressed in the hippocampus, but their respective roles in memory processes remain to be determined. In the present study, effects of selective SSTR1-4 agonists on memory formation were assessed in a water-maze task which can engage either hippocampus-dependent "place" and/or striatum-dependent "cue" memory formation. Mice received an intrahippocampal injection of one of each of the selective agonists and were then trained to locate an escape platform based on either distal cues (place memory) or a visible proximal cue (cue memory). Retention was tested 24 h later on probe trials aimed at identifying which memory strategy was preferentially retained. Both SS14 and the SSTR4 agonist (L-803,087) dramatically impaired place memory formation in a dose-dependent manner, whereas SSTR1 (L-797,591), SSTR2 (L-779,976), or SSTR3 (L-796,778) agonists did not yield any behavioral effects. However, unlike SS14, the SSTR4 agonist also dose-dependently enhanced cue-based memory formation. This effect was confirmed in another striatal-dependent memory task, the bar-pressing task, where L-803,087 improved memory of the instrumental response, whereas SS14 was once again ineffective. These data suggest that hippocampal SSTR4 are selectively involved in the selection of memory strategies by switching from the use of hippocampus-based multiple associations to the use of simple dorsal striatum-based behavioral responses. Possible neural mechanisms and functional implications are discussed.

Stochastic associative memory

NASA Astrophysics Data System (ADS)

Baumann, Erwin W.; Williams, David L.

1993-08-01

Artificial neural networks capable of learning and recalling stochastic associations between non-deterministic quantities have received relatively little attention to date. One potential application of such stochastic associative networks is the generation of sensory 'expectations' based on arbitrary subsets of sensor inputs to support anticipatory and investigate behavior in sensor-based robots. Another application of this type of associative memory is the prediction of how a scene will look in one spectral band, including noise, based upon its appearance in several other wavebands. This paper describes a semi-supervised neural network architecture composed of self-organizing maps associated through stochastic inter-layer connections. This 'Stochastic Associative Memory' (SAM) can learn and recall non-deterministic associations between multi-dimensional probability density functions. The stochastic nature of the network also enables it to represent noise distributions that are inherent in any true sensing process. The SAM architecture, training process, and initial application to sensor image prediction are described. Relationships to Fuzzy Associative Memory (FAM) are discussed.

Microstructure, crystallization and shape memory behavior of titania and yttria co-doped zirconia

DOE PAGES

Zeng, Xiao Mei; Du, Zehui; Schuh, Christopher A.; ...

2015-12-17

Small volume zirconia ceramics with few or no grain boundaries have been demonstrated recently to exhibit the shape memory effect. To explore the shape memory properties of yttria doped zirconia (YDZ), it is desirable to develop large, microscale grains, instead of submicron grains that result from typical processing of YDZ. In this paper, we have successfully produced single crystal micro-pillars from microscale grains encouraged by the addition of titania during processing. Titania has been doped into YDZ ceramics and its effect on the grain growth, crystallization and microscale elemental distribution of the ceramics have been systematically studied. With 5 mol%more » titania doping, the grain size can be increased up to ~4 μm, while retaining a large quantity of the desired tetragonal phase of zirconia. Finally, micro-pillars machined from tetragonal grains exhibit the expected shape memory effects where pillars made from titania-free YDZ would not.« less

Streptavidin-conjugated CdSe/ZnS quantum dots impaired synaptic plasticity and spatial memory process

NASA Astrophysics Data System (ADS)

Gao, Xiaoyan; Tang, Mingliang; Li, Zhifeng; Zha, Yingying; Cheng, Guosheng; Yin, Shuting; Chen, Jutao; Ruan, Di-yun; Chen, Lin; Wang, Ming

2013-04-01

Studies reported that quantum dots (QDs), as a novel probe, demonstrated a promising future for in vivo imaging, but also showed potential toxicity. This study is mainly to investigate in vivo response in the central nervous system (CNS) after exposure to QDs in a rat model of synaptic plasticity and spatial memory. Adult rats were exposed to streptavidin-conjugated CdSe/ZnS QDs (Qdots 525, purchased from Molecular Probes Inc.) by intraperitoneal injection for 7 days, followed by behavioral, electrophysiological, and biochemical examinations. The electrophysiological results show that input/output ( I/ O) functions were increased, while the peak of paired-pulse reaction and long-term potentiation were decreased after QDs insult, indicating synaptic transmission was enhanced and synaptic plasticity in the hippocampus was impaired. Meanwhile, behavioral experiments provide the evidence that QDs could impair rats' spatial memory process. All the results present evidences of interference of synaptic transmission and plasticity in rat hippocampal dentate gyrus area by QDs insult and suggest potential adverse issues which should be considered in QDs applications.

Molecular mechanisms of fear learning and memory.

PubMed

Johansen, Joshua P; Cain, Christopher K; Ostroff, Linnaea E; LeDoux, Joseph E

2011-10-28

Pavlovian fear conditioning is a particularly useful behavioral paradigm for exploring the molecular mechanisms of learning and memory because a well-defined response to a specific environmental stimulus is produced through associative learning processes. Synaptic plasticity in the lateral nucleus of the amygdala (LA) underlies this form of associative learning. Here, we summarize the molecular mechanisms that contribute to this synaptic plasticity in the context of auditory fear conditioning, the form of fear conditioning best understood at the molecular level. We discuss the neurotransmitter systems and signaling cascades that contribute to three phases of auditory fear conditioning: acquisition, consolidation, and reconsolidation. These studies suggest that multiple intracellular signaling pathways, including those triggered by activation of Hebbian processes and neuromodulatory receptors, interact to produce neural plasticity in the LA and behavioral fear conditioning. Collectively, this body of research illustrates the power of fear conditioning as a model system for characterizing the mechanisms of learning and memory in mammals and potentially for understanding fear-related disorders, such as PTSD and phobias. Copyright © 2011 Elsevier Inc. All rights reserved.

Mouse Cognition-Related Behavior in the Open-Field: Emergence of Places of Attraction

PubMed Central

Dvorkin, Anna; Benjamini, Yoav; Golani, Ilan

2008-01-01

Spatial memory is often studied in the Morris Water Maze, where the animal's spatial orientation has been shown to be mainly shaped by distal visual cues. Cognition-related behavior has also been described along “well-trodden paths”—spatial habits established by animals in the wild and in captivity reflecting a form of spatial memory. In the present study we combine the study of Open Field behavior with the study of behavior on well-trodden paths, revealing a form of locational memory that appears to correlate with spatial memory. The tracked path of the mouse is used to examine the dynamics of visiting behavior to locations. A visit is defined as either progressing through a location or stopping there, where progressing and stopping are computationally defined. We then estimate the probability of stopping at a location as a function of the number of previous visits to that location, i.e., we measure the effect of visiting history to a location on stopping in it. This can be regarded as an estimate of the familiarity of the mouse with locations. The recently wild-derived inbred strain CZECHII shows the highest effect of visiting history on stopping, C57 inbred mice show a lower effect, and DBA mice show no effect. We employ a rarely used, bottom-to-top computational approach, starting from simple kinematics of movement and gradually building our way up until we end with (emergent) locational memory. The effect of visiting history to a location on stopping in it can be regarded as an estimate of the familiarity of the mouse with locations, implying memory of these locations. We show that the magnitude of this estimate is strain-specific, implying a genetic influence. The dynamics of this process reveal that locations along the mouse's trodden path gradually become places of attraction, where the mouse stops habitually. PMID:18463701

Objectively-Measured Impulsivity and Attention-Deficit/Hyperactivity Disorder (ADHD): Testing Competing Predictions from the Working Memory and Behavioral Inhibition Models of ADHD

ERIC Educational Resources Information Center

Raiker, Joseph S.; Rapport, Mark D.; Kofler, Michael J.; Sarver, Dustin E.

2012-01-01

Impulsivity is a hallmark of two of the three DSM-IV ADHD subtypes and is associated with myriad adverse outcomes. Limited research, however, is available concerning the mechanisms and processes that contribute to impulsive responding by children with ADHD. The current study tested predictions from two competing models of ADHD--working memory (WM)…

Advanced Development of Certified OS Kernels

DTIC Science & Technology

2015-06-01

It provides an infrastructure to map a physical page into multiple processes’ page maps in different address spaces. Their ownership mechanism ensures...of their shared memory infrastructure . Trap module The trap module specifies the behaviors of exception handlers and mCertiKOS system calls. In...layers), 1 pm for the shared memory infrastructure (3 layers), 3.5 pm for the thread management (10 layers), 1 pm for the process management (4 layers

Adolescents at risk for drug abuse: a 3-year dual-process analysis.

PubMed

Ames, Susan L; Xie, Bin; Shono, Yusuke; Stacy, Alan W

2017-05-01

To test longitudinal additive and synergistic dual-process models in youth at documented risk for drug use. The specific dual-process approach examined suggests that engaging in drug use behaviors results from a dynamic interplay between automatically activated associative memory processes and executive reflective/control processes. This 3-year, three-wave population-based prospective study used mobile computer-based assessments. Self-directed computer assessments were completed in school settings in the Los Angeles metropolitan area, California, USA. Seven hundred and twenty-five at-risk adolescents (44% female) in continuation high schools were recruited during 9th grade (age at recruitment, 14-16). Key outcome measures included past year alcohol, marijuana and cigarette use at each assessment. Predictors included working memory capacity (WMC), associative memory, the interaction term WMC by associative memory, sex, age, ethnicity and acculturation. A significant cross-sectional interaction revealed tobacco-relevant associations were weaker predictors of cigarette use among males with higher WMC than among those with lower WMC (P < 0.004). Alternatively, drug-relevant associations were stronger predictors of past year alcohol (P < 0.001) and marijuana use (P = 0.02) among females with higher WMC than among those with lower WMC. Longitudinal analyses revealed no significant interactions after adjusting for predictive effects of previous drug use. With respect to WMC, females with higher WMC were less likely to use marijuana at 2-year follow-up (P = 0.03). First-order effects of drug-related associations predicted greater alcohol and marijuana use prospectively in males at 1- and 2-year follow up (P ≤ 0.03), and greater past year alcohol and marijuana use in females at 1-year follow up (P ≤ 0.03). Drug-relevant memory associations play a key role in drug use behavior in at-risk youth. © 2016 Society for the Study of Addiction.

Switching Attention Within Working Memory is Reflected in the P3a Component of the Human Event-Related Brain Potential

PubMed Central

Berti, Stefan

2016-01-01

The flexible access to information in working memory is crucial for adaptive behavior. It is assumed that this is realized by switching the focus of attention within working memory. Switching of attention is mirrored in the P3a component of the human event-related brain potential (ERP) and it has been argued that the processes reflected by the P3a are also relevant for selecting information within working memory. The aim of the present study was to further evaluate whether the P3a mirrors genuine switching of attention within working memory by applying an object switching task: Participants updated a memory list of four digits either by replacing one item with another digit or by processing the stored digit. ERPs were computed separately for two types of trials: (1) trials in which an object was repeated and (2) trials in which a switch to a new object was required in order to perform the task. Object-switch trials showed increased response times compared with repetition trials in both task conditions. In addition, switching costs were increased in the processing compared with the replacement condition. Pronounced P3a’s were obtained in switching trials but there were no difference between the two updating tasks (replacement or processing). These results were qualified by the finding that the magnitude of the visual location shift also affects the ERPs in the P3a time window. Taken together, the present pattern of results suggest that the P3a reflects an initial process of selecting information in working memory but not the memory updating itself. PMID:26779009

Multifaceted roles for low-frequency oscillations in bottom-up and top-down processing during navigation and memory.

PubMed

Ekstrom, Arne D; Watrous, Andrew J

2014-01-15

A prominent and replicated finding is the correlation between running speed and increases in low-frequency oscillatory activity in the hippocampal local field potential. A more recent finding concerns low-frequency oscillations that increase in coherence between the hippocampus and neocortical brain areas such as prefrontal cortex during memory-related behaviors (i.e., remembering the correct location to visit). In this review, we tie together movement-related and memory-related low-frequency oscillations in the rodent with similar findings in humans. We argue that although movement-related low-frequency oscillations, in particular, may have slightly different characteristics in humans than rodents, placing important constraints on our thinking about this issue, both phenomena have similar functional foundations. We review four prominent theoretical models that provide partially conflicting accounts of movement-related low-frequency oscillations. We attempt to tie together these theoretical proposals, and existing data in rodents and humans, with memory-related low-frequency oscillations. We propose that movement-related low-frequency oscillations and memory-related low-frequency oscillatory activity, both of which show significant coherence with oscillations in other brain regions, represent different facets of "spectral fingerprints," or different resonant frequencies within the same brain networks underlying different cognitive processes. Together, movement-related and memory-related low-frequency oscillatory coupling may be linked by their distinct contributions to bottom-up, sensorimotor driven processing and top-down, controlled processing characterizing aspects of memory encoding and retrieval. Copyright © 2013. Published by Elsevier Inc.

Multifaceted roles for low-frequency oscillations in bottom-up and top-down processing during navigation and memory

PubMed Central

Ekstrom, Arne D.; Watrous, Andrew J.

2014-01-01

A prominent and replicated finding is the correlation between running speed and increases in low-frequency oscillatory activity in the hippocampal local field potential. A more recent finding concerns low-frequency oscillations that increase in coherence between the hippocampus and neocortical brain areas such as prefrontal cortex during memory-related behaviors (i.e., remembering the correct arm to explore). In this review, we tie together movement-related and memory-related low-frequency oscillations in the rodent with similar findings in humans. We argue that although movement-related low-frequency oscillations, in particular, may have slightly different characteristics in humans than rodents, placing important constraints on our thinking about this issue, both phenomena have similar functional foundations. We review four prominent theoretical models that provide partially conflicting accounts of movement-related low-frequency oscillations. We attempt to tie together these theoretical proposals, and existing data in rodents and humans, with memory-related low-frequency oscillations. We propose that movement-related low-frequency oscillations and memory-related low-frequency oscillatory activity, both of which show significant coherence with oscillations in other brain regions, represent different facets of “spectral fingerprints,” or different resonant frequencies within the same brain networks underlying different cognitive processes. Together, movement-related and memory-related low-frequency oscillatory coupling may be linked by their distinct contributions to bottom-up, sensorimotor driven processing and top-down, controlled processing characterizing aspects of memory encoding and retrieval. PMID:23792985

The functional neuroanatomy of autobiographical memory: A meta-analysis

PubMed Central

Svoboda, Eva; McKinnon, Margaret C.; Levine, Brian

2007-01-01

Autobiographical memory (AM) entails a complex set of operations, including episodic memory, self-reflection, emotion, visual imagery, attention, executive functions, and semantic processes. The heterogeneous nature of AM poses significant challenges in capturing its behavioral and neuroanatomical correlates. Investigators have recently turned their attention to the functional neuroanatomy of AM. We used the effect-location method of meta-analysis to analyze data from 24 functional imaging studies of AM. The results indicated a core neural network of left-lateralized regions, including the medial and ventrolateral prefrontal, medial and lateral temporal and retrosplenial/posterior cingulate cortices, the temporoparietal junction and the cerebellum. Secondary and tertiary regions, less frequently reported in imaging studies of AM, are also identified. We examined the neural correlates of putative component processes in AM, including, executive functions, self-reflection, episodic remembering and visuospatial processing. We also separately analyzed the effect of select variables on the AM network across individual studies, including memory age, qualitative factors (personal significance, level of detail and vividness), semantic and emotional content, and the effect of reference conditions. We found that memory age effects on medial temporal lobe structures may be modulated by qualitative aspects of memory. Studies using rest as a control task masked process-specific components of the AM neural network. Our findings support a neural distinction between episodic and semantic memory in AM. Finally, emotional events produced a shift in lateralization of the AM network with activation observed in emotion-centered regions and deactivation (or lack of activation) observed in regions associated with cognitive processes. PMID:16806314

Expectancy effects in source memory: how moving to a bad neighborhood can change your memory.

PubMed

Kroneisen, Meike; Woehe, Larissa; Rausch, Leonie Sophie

2015-02-01

Enhanced memory for cheaters could be suited to avoid social exchange situations in which we run the risk of getting exploited by others. Several experiments demonstrated that we have better source memory for faces combined with negative rather than positive behavior (Bell & Buchner, Memory & Cognition, 38, 29-41, 2010) or for cheaters and cooperators showing unexpected behavior (Bell, Buchner, Kroneisen, Giang, Journal of Experimental Psychology: Learning, Memory, and Cognition, 38, 1512-1529, 2012). In the present study, we compared two groups: Group 1 just saw faces combined with aggressive, prosocial or neutral behavior descriptions, but got no further information, whereas group 2 was explicitly told that they would now see the behavior descriptions of very aggressive and unsocial persons. To measure old-new discrimination, source memory, and guessing biases separately, we used a multinomial model. When having no expectancies about the behavior of the presented people, enhanced source memory for aggressive persons was found. In comparison, source memory for faces combined with prosocial behavior descriptions was significantly higher in the group expecting only aggressive persons. These findings can be attributed to a mechanism that focuses on expectancy-incongruent information, representing a more flexible and therefore efficient memory strategy for remembering exchange-relevant information.

Anatomy and behavioral function of serotonin receptors in Drosophila melanogaster larvae.

PubMed

Huser, Annina; Eschment, Melanie; Güllü, Nazli; Collins, Katharina A N; Böpple, Kathrin; Pankevych, Lyubov; Rolsing, Emilia; Thum, Andreas S

2017-01-01

The biogenic amine serotonin (5-HT) is an important neuroactive molecule in the central nervous system of the majority of animal phyla. 5-HT binds to specific G protein-coupled and ligand-gated ion receptors to regulate particular aspects of animal behavior. In Drosophila, as in many other insects this includes the regulation of locomotion and feeding. Due to its genetic amenability and neuronal simplicity the Drosophila larva has turned into a useful model for studying the anatomical and molecular basis of chemosensory behaviors. This is particularly true for the olfactory system, which is mostly described down to the synaptic level over the first three orders of neuronal information processing. Here we focus on the 5-HT receptor system of the Drosophila larva. In a bipartite approach consisting of anatomical and behavioral experiments we describe the distribution and the implications of individual 5-HT receptors on naïve and acquired chemosensory behaviors. Our data suggest that 5-HT1A, 5-HT1B, and 5-HT7 are dispensable for larval naïve olfactory and gustatory choice behaviors as well as for appetitive and aversive associative olfactory learning and memory. In contrast, we show that 5-HT/5-HT2A signaling throughout development, but not as an acute neuronal function, affects associative olfactory learning and memory using high salt concentration as a negative unconditioned stimulus. These findings describe for the first time an involvement of 5-HT signaling in learning and memory in Drosophila larvae. In the longer run these results may uncover developmental, 5-HT dependent principles related to reinforcement processing possibly shared with adult Drosophila and other insects.

Anatomy and behavioral function of serotonin receptors in Drosophila melanogaster larvae

PubMed Central

Huser, Annina; Eschment, Melanie; Güllü, Nazli; Collins, Katharina A. N.; Böpple, Kathrin; Pankevych, Lyubov; Rolsing, Emilia; Thum, Andreas S.

2017-01-01

The biogenic amine serotonin (5-HT) is an important neuroactive molecule in the central nervous system of the majority of animal phyla. 5-HT binds to specific G protein-coupled and ligand-gated ion receptors to regulate particular aspects of animal behavior. In Drosophila, as in many other insects this includes the regulation of locomotion and feeding. Due to its genetic amenability and neuronal simplicity the Drosophila larva has turned into a useful model for studying the anatomical and molecular basis of chemosensory behaviors. This is particularly true for the olfactory system, which is mostly described down to the synaptic level over the first three orders of neuronal information processing. Here we focus on the 5-HT receptor system of the Drosophila larva. In a bipartite approach consisting of anatomical and behavioral experiments we describe the distribution and the implications of individual 5-HT receptors on naïve and acquired chemosensory behaviors. Our data suggest that 5-HT1A, 5-HT1B, and 5-HT7 are dispensable for larval naïve olfactory and gustatory choice behaviors as well as for appetitive and aversive associative olfactory learning and memory. In contrast, we show that 5-HT/5-HT2A signaling throughout development, but not as an acute neuronal function, affects associative olfactory learning and memory using high salt concentration as a negative unconditioned stimulus. These findings describe for the first time an involvement of 5-HT signaling in learning and memory in Drosophila larvae. In the longer run these results may uncover developmental, 5-HT dependent principles related to reinforcement processing possibly shared with adult Drosophila and other insects. PMID:28777821

Brain systems underlying attentional control and emotional distraction during working memory encoding.

PubMed

Ziaei, Maryam; Peira, Nathalie; Persson, Jonas

2014-02-15

Goal-directed behavior requires that cognitive operations can be protected from emotional distraction induced by task-irrelevant emotional stimuli. The brain processes involved in attending to relevant information while filtering out irrelevant information are still largely unknown. To investigate the neural and behavioral underpinnings of attending to task-relevant emotional stimuli while ignoring irrelevant stimuli, we used fMRI to assess brain responses during attentional instructed encoding within an emotional working memory (WM) paradigm. We showed that instructed attention to emotion during WM encoding resulted in enhanced performance, by means of increased memory performance and reduced reaction time, compared to passive viewing. A similar performance benefit was also demonstrated for recognition memory performance, although for positive pictures only. Functional MRI data revealed a network of regions involved in directed attention to emotional information for both positive and negative pictures that included medial and lateral prefrontal cortices, fusiform gyrus, insula, the parahippocampal gyrus, and the amygdala. Moreover, we demonstrate that regions in the striatum, and regions associated with the default-mode network were differentially activated for emotional distraction compared to neutral distraction. Activation in a sub-set of these regions was related to individual differences in WM and recognition memory performance, thus likely contributing to performing the task at an optimal level. The present results provide initial insights into the behavioral and neural consequences of instructed attention and emotional distraction during WM encoding. © 2013.

Predicting the integration of overlapping memories by decoding mnemonic processing states during learning

PubMed Central

Richter, Franziska R.; Chanales, Avi J. H.; Kuhl, Brice A.

2015-01-01

The hippocampal memory system is thought to alternate between two opposing processing states: encoding and retrieval. When present experience overlaps with past experience, this creates a potential tradeoff between encoding the present and retrieving the past. This tradeoff may be resolved by memory integration—that is, by forming a mnemonic representation that links present experience with overlapping past experience. Here, we used fMRI decoding analyses to predict when—and establish how—past and present experiences become integrated in memory. In an initial experiment, we alternately instructed subjects to adopt encoding, retrieval or integration states during overlapping learning. We then trained across-subject pattern classifiers to ‘read out’ the instructed processing states from fMRI activity patterns. We show that an integration state was clearly dissociable from encoding or retrieval states. Moreover, trial-by-trial fluctuations in decoded evidence for an integration state during learning reliably predicted behavioral expressions of successful memory integration. Strikingly, the decoding algorithm also successfully predicted specific instances of spontaneous memory integration in an entirely independent sample of subjects for whom processing state instructions were not administered. Finally, we show that medial prefrontal cortex and hippocampus differentially contribute to encoding, retrieval, and integration states: whereas hippocampus signals the tradeoff between encoding vs. retrieval states, medial prefrontal cortex actively represents past experience in relation to new learning. PMID:26327243

ERPs and oscillations during encoding predict retrieval of digit memory in superior mnemonists.

PubMed

Pan, Yafeng; Li, Xianchun; Chen, Xi; Ku, Yixuan; Dong, Yujie; Dou, Zheng; He, Lin; Hu, Yi; Li, Weidong; Zhou, Xiaolin

2017-10-01

Previous studies have consistently demonstrated that superior mnemonists (SMs) outperform normal individuals in domain-specific memory tasks. However, the neural correlates of memory-related processes remain unclear. In the current EEG study, SMs and control participants performed a digit memory task during which their brain activity was recorded. Chinese SMs used a digit-image mnemonic for encoding digits, in which they associated 2-digit groups with images immediately after the presentation of each even-position digit in sequences. Behaviorally, SMs' memory of digit sequences was better than the controls'. During encoding in the study phase, SMs showed an increased right central P2 (150-250ms post onset) and a larger right posterior high-alpha (10-14Hz, 500-1720ms) oscillation on digits at even-positions compared with digits at odd-positions. Both P2 and high-alpha oscillations in the study phase co-varied with performance in the recall phase, but only in SMs, indicating that neural dynamics during encoding could predict successful retrieval of digit memory in SMs. Our findings suggest that representation of a digit sequence in SMs using mnemonics may recruit both the early-stage attention allocation process and the sustained information preservation process. This study provides evidence for the role of dynamic and efficient neural encoding processes in mnemonists. Copyright © 2017. Published by Elsevier Inc.

Facilitating change in health-related behaviors and intentions: a randomized controlled trial of a multidimensional memory program for older adults.

PubMed

Wiegand, Melanie A; Troyer, Angela K; Gojmerac, Christina; Murphy, Kelly J

2013-01-01

Many older adults are concerned about memory changes with age and consequently seek ways to optimize their memory function. Memory programs are known to be variably effective in improving memory knowledge, other aspects of metamemory, and/or objective memory, but little is known about their impact on implementing and sustaining lifestyle and healthcare-seeking intentions and behaviors. We evaluated a multidimensional, evidence-based intervention, the Memory and Aging Program, that provides education about memory and memory change, training in the use of practical memory strategies, and support for implementation of healthy lifestyle behavior changes. In a randomized controlled trial, 42 healthy older adults participated in a program (n = 21) or a waitlist control (n = 21) group. Relative to the control group, participants in the program implemented more healthy lifestyle behaviors by the end of the program and maintained these changes 1 month later. Similarly, program participants reported a decreased intention to seek unnecessary medical attention for their memory immediately after the program and 1 month later. Findings support the use of multidimensional memory programs to promote healthy lifestyles and influence healthcare-seeking behaviors. Discussion focuses on implications of these changes for maximizing cognitive health and minimizing impact on healthcare resources.

Affect, accessibility of material in memory, and behavior: a cognitive loop?

PubMed

Isen, A M; Shalker, T E; Clark, M; Karp, L

1978-01-01

Two studies investigated the effect of good mood on cognitive processes. In the first study, conducted in a shopping mall, a positive feeling state was induced by giving subjects a free gift, and good mood, thus induced, was found to improve subjects' evaluations of the performance and service records of products they owned. In the second study, in which affect was induced by having subjects win or lose a computer game in a laboratory setting, subjects who had won the game were found to be better able to recall positive material in memory. The results of the two studies are discussed in terms of the effect that feelings have on accessibility of cognitions. In addition, the nature of affect and the relationship between good mood and behavior (such as helping) are discussed in terms of this proposed cognitive process.

Enhanced long-term recollection for emotional pictures: evidence from high-density ERPs.

PubMed

Weymar, Mathias; Löw, Andreas; Melzig, Christiane A; Hamm, Alfons O

2009-11-01

The present study used behavioral and electrophysiological measures to investigate the processes mediating long-term recognition memory for emotional and neutral pictures. The results show enhanced memory recollection for emotional arousing pictures compared to neutral low arousing pictures. In accordance with the behavioral data, we observed enhanced old/new effects in the ERPs for emotionally arousing pictures in the recollection-sensitive old/new component at centro-parietal sites (500-800 ms). Moreover, early old/new effects were present over frontal and parietal sites (300-500 ms) irrespective of picture contents. Analysis of the subjective awareness, indexed by the confidence ratings, showed that the late parietal old/new effect was increased for high confidence responses whereas the early component (300-500 ms) was mainly driven by low confidence responses, an indication for familiarity based recognition processes.

Aging and selective engagement: the moderating impact of motivation on older adults' resource utilization.

PubMed

Hess, Thomas M; Germain, Cassandra M; Swaim, Elizabeth L; Osowski, Nicole L

2009-06-01

Two studies were conducted to examine age differences in the impact of motivation in a social cognitive task. We tested the hypothesis that aging is associated with an increase in the selective engagement of cognitive resources in support of performance. Different-aged adults read descriptions of 2 people in order to determine which was better suited for a particular job. These descriptions contained behaviors that were either consistent or inconsistent with the job, and participants performed the task under conditions of high versus low accountability. Examination of memory for behavioral information revealed that accountability disproportionately affected older adults' performance, with the locus of this effect being in conscious recollection processes. This supports the aforementioned selective engagement hypothesis by demonstrating that the differential impact of the motivational manipulation was based in deliberative memory processes.

A top-down perspective on dopamine, motivation and memory.

PubMed

Phillips, Anthony G; Vacca, Giada; Ahn, Soyon

2008-08-01

Dopamine (DA) activity, in the form of increased neural firing or enhanced release of transmitter from nerve terminals and varicosities, is linked to a number of important psychological processes including: movement; hedonic reactions to positive reward; provision of an error detection signal during the acquisition of new learning; response to novel stimuli; provision of reinforcement signals essential for acquisition of new action patterns; and incentive motivation. This review focuses primarily on our research linking dynamic changes in DA efflux on the timescale of minutes, with incentive motivation, as revealed by brain dialysis experiments in behaving animals. Recent experiments on sensory-specific satiety and successive positive and negative contrast are discussed along with the distinction between preparatory behaviors that precede contact with biologically significant stimuli and subsequent consummatory behaviors. The relationship between DA efflux in the medial prefrontal cortex (mPFC) and foraging for food based on working memory is also discussed in support of the conjecture that DA may serve as a link between motivation and memory functions. Evidence in support of 'top-down' regulation of dopaminergic activity in the mesocorticolimbic DA pathways is reviewed briefly to introduce a mechanism by which activation of ascending DA projections in this manner might optimize dopaminergic modulation of executive function within regions such as the mPFC. Collectively, these processes could ensure coordination between cognitive processes that assess current opportunities and the motivational systems that select and engage patterns of approach behavior that bring organisms into contact with the essentials for survival.

Inhibition-Induced Forgetting Results from Resource Competition between Response Inhibition and Memory Encoding Processes.

PubMed

Chiu, Yu-Chin; Egner, Tobias

2015-08-26

Response inhibition is a key component of executive control, but its relation to other cognitive processes is not well understood. We recently documented the "inhibition-induced forgetting effect": no-go cues are remembered more poorly than go cues. We attributed this effect to central-resource competition, whereby response inhibition saps attention away from memory encoding. However, this proposal is difficult to test with behavioral means alone. We therefore used fMRI in humans to test two neural predictions of the "common resource hypothesis": (1) brain regions associated with response inhibition should exhibit greater resource demands during encoding of subsequently forgotten than remembered no-go cues; and (2) this higher inhibitory resource demand should lead to memory encoding regions having less resources available during encoding of subsequently forgotten no-go cues. Participants categorized face stimuli by gender in a go/no-go task and, following a delay, performed a surprise recognition memory test for those faces. Replicating previous findings, memory was worse for no-go than for go stimuli. Crucially, forgetting of no-go cues was predicted by high inhibitory resource demand, as quantified by the trial-by-trial ratio of activity in neural "no-go" versus "go" networks. Moreover, this index of inhibitory demand exhibited an inverse trial-by-trial relationship with activity in brain regions responsible for the encoding of no-go cues into memory, notably the ventrolateral prefrontal cortex. This seesaw pattern between the neural resource demand of response inhibition and activity related to memory encoding directly supports the hypothesis that response inhibition temporarily saps attentional resources away from stimulus processing. Recent behavioral experiments showed that inhibiting a motor response to a stimulus (a "no-go cue") impairs subsequent memory for that cue. Here, we used fMRI to test whether this "inhibition-induced forgetting effect" is caused by competition for neural resources between the processes of response inhibition and memory encoding. We found that trial-by-trial variations in neural inhibitory resource demand predicted subsequent forgetting of no-go cues and that higher inhibitory demand was furthermore associated with lower concurrent activation in brain regions responsible for successful memory encoding of no-go cues. Thus, motor inhibition and stimulus encoding appear to compete with each other: when more resources have to be devoted to inhibiting action, less are available for encoding sensory stimuli. Copyright © 2015 the authors 0270-6474/15/3511936-10$15.00/0.

Neural and Cellular Mechanisms of Fear and Extinction Memory Formation

PubMed Central

Orsini, Caitlin A.; Maren, Stephen

2012-01-01

Over the course of natural history, countless animal species have evolved adaptive behavioral systems to cope with dangerous situations and promote survival. Emotional memories are central to these defense systems because they are rapidly acquired and prepare organisms for future threat. Unfortunately, the persistence and intrusion of memories of fearful experiences are quite common and can lead to pathogenic conditions, such as anxiety and phobias. Over the course of the last thirty years, neuroscientists and psychologists alike have attempted to understand the mechanisms by which the brain encodes and maintains these aversive memories. Of equal interest, though, is the neurobiology of extinction memory formation as this may shape current therapeutic techniques. Here we review the extant literature on the neurobiology of fear and extinction memory formation, with a strong focus on the cellular and molecular mechanisms underlying these processes. PMID:22230704

The Influences of Emotion on Learning and Memory

PubMed Central

Tyng, Chai M.; Amin, Hafeez U.; Saad, Mohamad N. M.; Malik, Aamir S.

2017-01-01

Emotion has a substantial influence on the cognitive processes in humans, including perception, attention, learning, memory, reasoning, and problem solving. Emotion has a particularly strong influence on attention, especially modulating the selectivity of attention as well as motivating action and behavior. This attentional and executive control is intimately linked to learning processes, as intrinsically limited attentional capacities are better focused on relevant information. Emotion also facilitates encoding and helps retrieval of information efficiently. However, the effects of emotion on learning and memory are not always univalent, as studies have reported that emotion either enhances or impairs learning and long-term memory (LTM) retention, depending on a range of factors. Recent neuroimaging findings have indicated that the amygdala and prefrontal cortex cooperate with the medial temporal lobe in an integrated manner that affords (i) the amygdala modulating memory consolidation; (ii) the prefrontal cortex mediating memory encoding and formation; and (iii) the hippocampus for successful learning and LTM retention. We also review the nested hierarchies of circular emotional control and cognitive regulation (bottom-up and top-down influences) within the brain to achieve optimal integration of emotional and cognitive processing. This review highlights a basic evolutionary approach to emotion to understand the effects of emotion on learning and memory and the functional roles played by various brain regions and their mutual interactions in relation to emotional processing. We also summarize the current state of knowledge on the impact of emotion on memory and map implications for educational settings. In addition to elucidating the memory-enhancing effects of emotion, neuroimaging findings extend our understanding of emotional influences on learning and memory processes; this knowledge may be useful for the design of effective educational curricula to provide a conducive learning environment for both traditional “live” learning in classrooms and “virtual” learning through online-based educational technologies. PMID:28883804

Segregating the core computational faculty of human language from working memory.

PubMed

Makuuchi, Michiru; Bahlmann, Jörg; Anwander, Alfred; Friederici, Angela D

2009-05-19

In contrast to simple structures in animal vocal behavior, hierarchical structures such as center-embedded sentences manifest the core computational faculty of human language. Previous artificial grammar learning studies found that the left pars opercularis (LPO) subserves the processing of hierarchical structures. However, it is not clear whether this area is activated by the structural complexity per se or by the increased memory load entailed in processing hierarchical structures. To dissociate the effect of structural complexity from the effect of memory cost, we conducted a functional magnetic resonance imaging study of German sentence processing with a 2-way factorial design tapping structural complexity (with/without hierarchical structure, i.e., center-embedding of clauses) and working memory load (long/short distance between syntactically dependent elements; i.e., subject nouns and their respective verbs). Functional imaging data revealed that the processes for structure and memory operate separately but co-operatively in the left inferior frontal gyrus; activities in the LPO increased as a function of structural complexity, whereas activities in the left inferior frontal sulcus (LIFS) were modulated by the distance over which the syntactic information had to be transferred. Diffusion tensor imaging showed that these 2 regions were interconnected through white matter fibers. Moreover, functional coupling between the 2 regions was found to increase during the processing of complex, hierarchically structured sentences. These results suggest a neuroanatomical segregation of syntax-related aspects represented in the LPO from memory-related aspects reflected in the LIFS, which are, however, highly interconnected functionally and anatomically.

Patients with Mild Alzheimer's Disease Fail When Using Their Working Memory: Evidence from the Eye Tracking Technique.

PubMed

Fernández, Gerardo; Manes, Facundo; Politi, Luis E; Orozco, David; Schumacher, Marcela; Castro, Liliana; Agamennoni, Osvaldo; Rotstein, Nora P

2016-01-01

Patients with Alzheimer's disease (AD) develop progressive language, visuoperceptual, attentional, and oculomotor changes that can have an impact on their reading comprehension. However, few studies have examined reading behavior in AD, and none have examined the contribution of predictive cueing in reading performance. For this purpose we analyzed the eye movement behavior of 35 healthy readers (Controls) and 35 patients with probable AD during reading of regular and high-predictable sentences. The cloze predictability of words N - 1, and N + 1 exerted an influence on the reader's gaze duration. The predictabilities of preceding words in high-predictable sentences served as task-appropriate cues that were used by Control readers. In contrast, these effects were not present in AD patients. In Controls, changes in predictability significantly affected fixation duration along the sentence; noteworthy, these changes did not affect fixation durations in AD patients. Hence, only in healthy readers did predictability of upcoming words influence fixation durations via memory retrieval. Our results suggest that Controls used stored information of familiar texts for enhancing their reading performance and imply that contextual-word predictability, whose processing is proposed to require memory retrieval, only affected reading behavior in healthy subjects. In AD patients, this loss reveals impairments in brain areas such as those corresponding to working memory and memory retrieval. These findings might be relevant for expanding the options for the early detection and monitoring in the early stages of AD. Furthermore, evaluation of eye movements during reading could provide a new tool for measuring drug impact on patients' behavior.

Epigenetic mechanisms in experience-driven memory formation and behavior.

PubMed

Puckett, Rosemary E; Lubin, Farah D

2011-10-01

Epigenetic mechanisms have long been associated with the regulation of gene-expression changes accompanying normal neuronal development and cellular differentiation; however, until recently these mechanisms were believed to be statically quiet in the adult brain. Behavioral neuroscientists have now begun to investigate these epigenetic mechanisms as potential regulators of gene-transcription changes in the CNS subserving synaptic plasticity and long-term memory (LTM) formation. Experimental evidence from learning and memory animal models has demonstrated that active chromatin remodeling occurs in terminally differentiated postmitotic neurons, suggesting that these molecular processes are indeed intimately involved in several stages of LTM formation, including consolidation, reconsolidation and extinction. Such chromatin modifications include the phosphorylation, acetylation and methylation of histone proteins and the methylation of associated DNA to subsequently affect transcriptional gene readout triggered by learning. The present article examines how such learning-induced epigenetic changes contribute to LTM formation and influence behavior. In particular, this article is a survey of the specific epigenetic mechanisms that have been demonstrated to regulate gene expression for both transcription factors and growth factors in the CNS, which are critical for LTM formation and storage, as well as how aberrant epigenetic processing can contribute to psychological states such as schizophrenia and drug addiction. Together, the findings highlighted in this article support a novel role for epigenetic mechanisms in the adult CNS serving as potential key molecular regulators of gene-transcription changes necessary for LTM formation and adult behavior.

Colloquium on Selected Topics in Behavioral Science Basic Research. (Alexandria, Virginia, April 23-25, 1980).

ERIC Educational Resources Information Center

Nogami, Glenda Y., Ed.; And Others

The 21 summaries of research programs, funded by the United States Army Research Institute (ARI) for the Behavioral and Social Sciences which are presented are grouped in five broad topic areas: computer-based systems; information processing; learning, memory and transfer; human relations; and related issues and trends. Papers presented include:…

Effects of β-adrenergic receptor blockade on drug-related memory reconsolidation in abstinent heroin addicts.

PubMed

Zhao, Li-Yan; Sun, Li-Li; Shi, Jie; Li, Peng; Zhang, Yan; Lu, Lin

2011-11-01

The reactivation of a consolidated memory can return it to a labile state, a process referred to as reconsolidation. A previous study showed that oral administration of the β-adrenergic receptor antagonist propranolol before memory reactivation in humans erased the behavioral expression of the fear memory 24h later. In this study, we investigated whether propranolol impairs the drug-related memory by disrupting the reconsolidation process in heroin addicts. Seventy abstinent heroin addicts learned a word list (including 10 heroin-related positive words, 10 heroin-related negative words, and 10 neutral words) on day 1. Participants orally administered the β-adrenergic receptor antagonist propranolol or placebo before retrieval of the word list on day 2. Free recall of the word list and other psychological and physical responses were assessed on day 3. Oral administration of propranolol before reactivation of the word list impaired reconsolidation of drug-related positive and negative but not neutral words in abstinent heroin addicts, and these impairments critically depended on reactivation of the word list. This study extends earlier reports that a β-adrenergic receptor antagonist affects the drug-related memory reconsolidation process. Our findings may have important implications for the understanding and treatment of persistent and abnormal drug-related memories in abstinent heroin addicts. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Neural and Behavioral Evidence for an Online Resetting Process in Visual Working Memory.

PubMed

Balaban, Halely; Luria, Roy

2017-02-01

Visual working memory (VWM) guides behavior by holding a set of active representations and modifying them according to changes in the environment. This updating process relies on a unique mapping between each VWM representation and an actual object in the environment. Here, we destroyed this mapping by either presenting a coherent object but then breaking it into independent parts or presenting an object but then abruptly replacing it with a different object. This allowed us to introduce the neural marker and behavioral consequence of an online resetting process in humans' VWM. Across seven experiments, we demonstrate that this resetting process involves abandoning the old VWM contents because they no longer correspond to the objects in the environment. Then, VWM encodes the novel information and reestablishes the correspondence between the new representations and the objects. The resetting process was marked by a unique neural signature: a sharp drop in the amplitude of the electrophysiological index of VWM contents (the contralateral delay activity), presumably indicating the loss of the existent object-to-representation mappings. This marker was missing when an updating process occurred. Moreover, when tracking moving items, VWM failed to detect salient changes in the object's shape when these changes occurred during the resetting process. This happened despite the object being fully visible, presumably because the mapping between the object and a VWM representation was lost. Importantly, we show that resetting, its neural marker, and the behavioral cost it entails, are specific to situations that involve a destruction of the objects-to-representations correspondence. Visual working memory (VWM) maintains task-relevant information in an online state. Previous studies showed that VWM representations are accessed and modified after changes in the environment. Here, we show that this updating process critically depends on an ongoing mapping between the representations and the objects in the environment. When this mapping breaks, VWM cannot access the old representations and instead resets. The novel resetting process that we introduce removes the existing representations instead of modifying them and this process is accompanied by a unique neural marker. During the resetting process, VWM was blind to salient changes in the object's shape. The resetting process highlights the flexibility of our cognitive system in handling the dynamic environment by abruptly abandoning irrelevant schemas. Copyright © 2017 the authors 0270-6474/17/371225-15$15.00/0.

The effect of exogenous cortisol during sleep on the behavioral and neural correlates of emotional memory consolidation in humans.

PubMed

van Marle, Hein J F; Hermans, Erno J; Qin, Shaozheng; Overeem, Sebastiaan; Fernández, Guillén

2013-09-01

A host of animal work demonstrates that the retention benefit for emotionally aversive over neutral memories is regulated by glucocorticoid action during memory consolidation. Particularly, glucocorticoids may affect systems-level processes that promote the gradual reorganization of emotional memory traces. These effects remain largely uninvestigated in humans. Therefore, in this functional magnetic resonance imaging study we administered hydrocortisone during a polysomnographically monitored night of sleep directly after healthy volunteers studied negative and neutral pictures in a double-blind, placebo-controlled, between-subjects design. The following evening memory consolidation was probed during a recognition memory test in the MR scanner by assessing the difference in brain activity associated with memory for the consolidated items studied before sleep and new, unconsolidated items studied shortly before test (remote vs. recent memory paradigm). Hydrocortisone administration resulted in elevated cortisol levels throughout the experimental night with no group difference at recent encoding or test. Behaviorally, we showed that cortisol enhanced the difference between emotional and neutral consolidated memory, effectively prioritizing emotional memory consolidation. On a neural level, we found that cortisol reduced amygdala reactivity related to the retrieval of these same consolidated, negative items. These findings show that cortisol administration during first post-encoding sleep had a twofold effect on the first 24h of emotional memory consolidation. While cortisol prioritized recognition memory for emotional items, it reduced reactivation of the neural circuitry underlying emotional responsiveness during retrieval. These findings fit recent theories on emotional depotentiation following consolidation during sleep, although future research should establish the sleep-dependence of this effect. Moreover, our data may shed light on mechanisms underlying potential therapeutic effects of cortisol administration following psychological trauma. Copyright © 2013 Elsevier Ltd. All rights reserved.

Auditory short-term memory in the primate auditory cortex.

PubMed

Scott, Brian H; Mishkin, Mortimer

2016-06-01

Sounds are fleeting, and assembling the sequence of inputs at the ear into a coherent percept requires auditory memory across various time scales. Auditory short-term memory comprises at least two components: an active ׳working memory' bolstered by rehearsal, and a sensory trace that may be passively retained. Working memory relies on representations recalled from long-term memory, and their rehearsal may require phonological mechanisms unique to humans. The sensory component, passive short-term memory (pSTM), is tractable to study in nonhuman primates, whose brain architecture and behavioral repertoire are comparable to our own. This review discusses recent advances in the behavioral and neurophysiological study of auditory memory with a focus on single-unit recordings from macaque monkeys performing delayed-match-to-sample (DMS) tasks. Monkeys appear to employ pSTM to solve these tasks, as evidenced by the impact of interfering stimuli on memory performance. In several regards, pSTM in monkeys resembles pitch memory in humans, and may engage similar neural mechanisms. Neural correlates of DMS performance have been observed throughout the auditory and prefrontal cortex, defining a network of areas supporting auditory STM with parallels to that supporting visual STM. These correlates include persistent neural firing, or a suppression of firing, during the delay period of the memory task, as well as suppression or (less commonly) enhancement of sensory responses when a sound is repeated as a ׳match' stimulus. Auditory STM is supported by a distributed temporo-frontal network in which sensitivity to stimulus history is an intrinsic feature of auditory processing. This article is part of a Special Issue entitled SI: Auditory working memory. Published by Elsevier B.V.

Individual Differences in Working Memory Capacity and Dual-Process Theories of the Mind

ERIC Educational Resources Information Center

Barrett, Lisa Feldman; Tugade, Michele M.; Engle, Randall W.

2004-01-01

Dual-process theories of the mind are ubiquitous in psychology. A central principle of these theories is that behavior is determined by the interplay of automatic and controlled processing. In this article, the authors examine individual differences in the capacity to control attention as a major contributor to differences in working memory…

Emotional arousal and multiple memory systems in the mammalian brain

PubMed Central

Packard, Mark G.; Goodman, Jarid

2012-01-01

Emotional arousal induced by stress and/or anxiety can exert complex effects on learning and memory processes in mammals. Recent studies have begun to link study of the influence of emotional arousal on memory with earlier research indicating that memory is organized in multiple systems in the brain that differ in terms of the “type” of memory they mediate. Specifically, these studies have examined whether emotional arousal may have a differential effect on the “cognitive” and stimulus-response “habit” memory processes sub-served by the hippocampus and dorsal striatum, respectively. Evidence indicates that stress or the peripheral injection of anxiogenic drugs can bias animals and humans toward the use of striatal-dependent habit memory in dual-solution tasks in which both hippocampal and striatal-based strategies can provide an adequate solution. A bias toward the use of habit memory can also be produced by intra-basolateral amygdala (BLA) administration of anxiogenic drugs, consistent with the well documented role of efferent projections of this brain region in mediating the modulatory influence of emotional arousal on memory. In some learning situations, the bias toward the use of habit memory produced by emotional arousal appears to result from an impairing effect on hippocampus-dependent cognitive memory. Further research examining the neural mechanisms linking emotion and the relative use of multiple memory systems should prove useful in view of the potential role for maladaptive habitual behaviors in various human psychopathologies. PMID:22470324

Emotion impairs extrinsic source memory--An ERP study.

PubMed

Mao, Xinrui; You, Yuqi; Li, Wen; Guo, Chunyan

2015-09-01

Substantial advancements in understanding emotional modulation of item memory notwithstanding, controversies remain as to how emotion influences source memory. Using an emotional extrinsic source memory paradigm combined with remember/know judgments and two key event-related potentials (ERPs)-the FN400 (a frontal potential at 300-500 ms related to familiarity) and the LPC (a later parietal potential at 500-700 ms related to recollection), our research investigated the impact of emotion on extrinsic source memory and the underlying processes. We varied a semantic prompt (either "people" or "scene") preceding a study item to manipulate the extrinsic source. Behavioral data indicated a significant effect of emotion on "remember" responses to extrinsic source details, suggesting impaired recollection-based source memory in emotional (both positive and negative) relative to neutral conditions. In parallel, differential FN400 and LPC amplitudes (correctly remembered - incorrectly remembered sources) revealed emotion-related interference, suggesting impaired familiarity and recollection memory of extrinsic sources associated with positive or negative items. These findings thus lend support to the notion of emotion-induced memory trade off: while enhancing memory of central items and intrinsic/integral source details, emotion nevertheless disrupts memory of peripheral contextual details, potentially impairing both familiarity and recollection. Importantly, that positive and negative items result in comparable memory impairment suggests that arousal (vs. affective valence) plays a critical role in modulating dynamic interactions among automatic and elaborate processes involved in memory. Copyright © 2015 Elsevier B.V. All rights reserved.

Encoding processes during retrieval tasks.

PubMed

Buckner, R L; Wheeler, M E; Sheridan, M A

2001-04-01

Episodic memory encoding is pervasive across many kinds of task and often arises as a secondary processing effect in tasks that do not require intentional memorization. To illustrate the pervasive nature of information processing that leads to episodic encoding, a form of incidental encoding was explored based on the "Testing" phenomenon: The incidental-encoding task was an episodic memory retrieval task. Behavioral data showed that performing a memory retrieval task was as effective as intentional instructions at promoting episodic encoding. During fMRI imaging, subjects viewed old and new words and indicated whether they remembered them. Relevant to encoding, the fate of the new words was examined using a second, surprise test of recognition after the imaging session. fMRI analysis of those new words that were later remembered revealed greater activity in left frontal regions than those that were later forgotten - the same pattern of results as previously observed for traditional incidental and intentional episodic encoding tasks. This finding may offer a partial explanation for why repeated testing improves memory performance. Furthermore, the observation of correlates of episodic memory encoding during retrieval tasks challenges some interpretations that arise from direct comparisons between "encoding tasks" and "retrieval tasks" in imaging data. Encoding processes and their neural correlates may arise in many tasks, even those nominally labeled as retrieval tasks by the experimenter.

Working memory training improves visual short-term memory capacity.

PubMed

Schwarb, Hillary; Nail, Jayde; Schumacher, Eric H

2016-01-01

Since antiquity, philosophers, theologians, and scientists have been interested in human memory. However, researchers today are still working to understand the capabilities, boundaries, and architecture. While the storage capabilities of long-term memory are seemingly unlimited (Bahrick, J Exp Psychol 113:1-2, 1984), working memory, or the ability to maintain and manipulate information held in memory, seems to have stringent capacity limits (e.g., Cowan, Behav Brain Sci 24:87-185, 2001). Individual differences, however, do exist and these differences can often predict performance on a wide variety of tasks (cf. Engle What is working-memory capacity? 297-314, 2001). Recently, researchers have promoted the enticing possibility that simple behavioral training can expand the limits of working memory which indeed may also lead to improvements on other cognitive processes as well (cf. Morrison and Chein, Psychol Bull Rev 18:46-60 2011). However, initial investigations across a wide variety of cognitive functions have produced mixed results regarding the transferability of training-related improvements. Across two experiments, the present research focuses on the benefit of working memory training on visual short-term memory capacity-a cognitive process that has received little attention in the training literature. Data reveal training-related improvement of global measures of visual short-term memory as well as of measures of the independent sub-processes that contribute to capacity (Awh et al., Psychol Sci 18(7):622-628, 2007). These results suggest that the ability to inhibit irrelevant information within and between trials is enhanced via n-back training allowing for selective improvement on untrained tasks. Additionally, we highlight a potential limitation of the standard adaptive training procedure and propose a modified design to ensure variability in the training environment.

Learning to use working memory: a reinforcement learning gating model of rule acquisition in rats

PubMed Central

Lloyd, Kevin; Becker, Nadine; Jones, Matthew W.; Bogacz, Rafal

2012-01-01

Learning to form appropriate, task-relevant working memory representations is a complex process central to cognition. Gating models frame working memory as a collection of past observations and use reinforcement learning (RL) to solve the problem of when to update these observations. Investigation of how gating models relate to brain and behavior remains, however, at an early stage. The current study sought to explore the ability of simple RL gating models to replicate rule learning behavior in rats. Rats were trained in a maze-based spatial learning task that required animals to make trial-by-trial choices contingent upon their previous experience. Using an abstract version of this task, we tested the ability of two gating algorithms, one based on the Actor-Critic and the other on the State-Action-Reward-State-Action (SARSA) algorithm, to generate behavior consistent with the rats'. Both models produced rule-acquisition behavior consistent with the experimental data, though only the SARSA gating model mirrored faster learning following rule reversal. We also found that both gating models learned multiple strategies in solving the initial task, a property which highlights the multi-agent nature of such models and which is of importance in considering the neural basis of individual differences in behavior. PMID:23115551

Auditory short-term memory in the primate auditory cortex

PubMed Central

Scott, Brian H.; Mishkin, Mortimer

2015-01-01

Sounds are fleeting, and assembling the sequence of inputs at the ear into a coherent percept requires auditory memory across various time scales. Auditory short-term memory comprises at least two components: an active ‘working memory’ bolstered by rehearsal, and a sensory trace that may be passively retained. Working memory relies on representations recalled from long-term memory, and their rehearsal may require phonological mechanisms unique to humans. The sensory component, passive short-term memory (pSTM), is tractable to study in nonhuman primates, whose brain architecture and behavioral repertoire are comparable to our own. This review discusses recent advances in the behavioral and neurophysiological study of auditory memory with a focus on single-unit recordings from macaque monkeys performing delayed-match-to-sample (DMS) tasks. Monkeys appear to employ pSTM to solve these tasks, as evidenced by the impact of interfering stimuli on memory performance. In several regards, pSTM in monkeys resembles pitch memory in humans, and may engage similar neural mechanisms. Neural correlates of DMS performance have been observed throughout the auditory and prefrontal cortex, defining a network of areas supporting auditory STM with parallels to that supporting visual STM. These correlates include persistent neural firing, or a suppression of firing, during the delay period of the memory task, as well as suppression or (less commonly) enhancement of sensory responses when a sound is repeated as a ‘match’ stimulus. Auditory STM is supported by a distributed temporo-frontal network in which sensitivity to stimulus history is an intrinsic feature of auditory processing. PMID:26541581

Nanoscale Mechanical Stimulation Method for Quantifying C. elegans Mechanosensory Behavior and Memory.

PubMed

Sugi, Takuma; Okumura, Etsuko; Kiso, Kaori; Igarashi, Ryuji

2016-01-01

Withdrawal escape response of C. elegans to nonlocalized vibration is a useful behavioral paradigm to examine mechanisms underlying mechanosensory behavior and its memory-dependent change. However, there are very few methods for investigating the degree of vibration frequency, amplitude and duration needed to induce behavior and memory. Here, we establish a new system to quantify C. elegans mechanosensory behavior and memory using a piezoelectric sheet speaker. In the system, we can flexibly change the vibration properties at a nanoscale displacement level and quantify behavioral responses under each vibration property. This system is an economic setup and easily replicated in other laboratories. By using the system, we clearly detected withdrawal escape responses and confirmed habituation memory. This system will facilitate the understanding of physiological aspects of C. elegans mechanosensory behavior in the future.

Multimaterial 4D Printing with Tailorable Shape Memory Polymers

PubMed Central

Ge, Qi; Sakhaei, Amir Hosein; Lee, Howon; Dunn, Conner K.; Fang, Nicholas X.; Dunn, Martin L.

2016-01-01

We present a new 4D printing approach that can create high resolution (up to a few microns), multimaterial shape memory polymer (SMP) architectures. The approach is based on high resolution projection microstereolithography (PμSL) and uses a family of photo-curable methacrylate based copolymer networks. We designed the constituents and compositions to exhibit desired thermomechanical behavior (including rubbery modulus, glass transition temperature and failure strain which is more than 300% and larger than any existing printable materials) to enable controlled shape memory behavior. We used a high resolution, high contrast digital micro display to ensure high resolution of photo-curing methacrylate based SMPs that requires higher exposure energy than more common acrylate based polymers. An automated material exchange process enables the manufacture of 3D composite architectures from multiple photo-curable SMPs. In order to understand the behavior of the 3D composite microarchitectures, we carry out high fidelity computational simulations of their complex nonlinear, time-dependent behavior and study important design considerations including local deformation, shape fixity and free recovery rate. Simulations are in good agreement with experiments for a series of single and multimaterial components and can be used to facilitate the design of SMP 3D structures. PMID:27499417

The lasting memory enhancements of retrospective attention

PubMed Central

Reaves, Sarah; Strunk, Jonathan; Phillips, Shekinah; Verhaeghen, Paul; Duarte, Audrey

2016-01-01

Behavioral research has shown that spatial cues that orient attention toward task relevant items being maintained in visual short-term memory (VSTM) enhance item memory accuracy. However, it is unknown if these retrospective attentional cues (“retro-cues”) enhance memory beyond typical short-term memory delays. It is also unknown whether retro-cues affect the spatial information associated with VSTM representations. Emerging evidence suggests that processes that affect short-term memory maintenance may also affect long-term memory (LTM) but little work has investigated the role of attention in LTM. In the current event-related potential (ERP) study, we investigated the duration of retrospective attention effects and the impact of retrospective attention manipulations on VSTM representations. Results revealed that retro-cueing improved both VSTM and LTM memory accuracy and that posterior maximal ERPs observed during VSTM maintenance predicted subsequent LTM performance. N2pc ERPs associated with attentional selection were attenuated by retro-cueing suggesting that retrospective attention may disrupt maintenance of spatial configural information in VSTM. Collectively, these findings suggest that retrospective attention can alter the structure of memory representations, which impacts memory performance beyond short-term memory delays. PMID:27038756

The role of inhibition for working memory processes: ERP evidence from a short-term storage task.

PubMed

Getzmann, Stephan; Wascher, Edmund; Schneider, Daniel

2018-05-01

Human working memory is the central unit for short-term storage of information. In addition to the selection and adequate storage of relevant information, the suppression of irrelevant stimuli from the environment seems to be of importance for working memory processes. To learn more about the interplay of information uptake and inhibition of irrelevant information, the present study used ERP measures and a short-term storage and retrieval task, in which pairs of either numbers or letters had to be compared. Random sequences of four stimuli (two numbers and two letters) were presented, with either the numbers or the letters being relevant for comparison. The analysis of ERPs to each of the four stimuli indicated more pronounced P2 and P3b amplitudes for relevant than irrelevant stimuli. In contrast, the N2 (reflecting inhibitory control) was only elicited by irrelevant stimuli. Moreover, the N2 amplitude of the second irrelevant stimulus was associated with behavioral performance, indicating the importance of inhibition of task-irrelevant stimuli for working memory processes. In sum, the findings demonstrate the role of cognitive control mechanisms for protecting relevant contents in working memory against irrelevant information. © 2017 Society for Psychophysiological Research.

HDAC3 and the Molecular Brake Pad Hypothesis

PubMed Central

McQuown, Susan C.; Wood, Marcelo A.

2011-01-01

Successful transcription of specific genes required for long-term memory processes involves the orchestrated effort of not only transcription factors, but also very specific enzymatic protein complexes that modify chromatin structure. Chromatin modification has been identified as a pivotal molecular mechanism underlying certain forms of synaptic plasticity and memory. The best-studied form of chromatin modification in the learning and memory field is histone acetylation, which is regulated by histone acetyltransferases and histone deacetylases (HDACs). HDAC inhibitors have been shown to strongly enhance long-term memory processes, and recent work has aimed to identify contributions of individual HDACs. In this review, we focus on HDAC3 and discuss its recently defined role as a negative regulator of long-term memory formation. HDAC3 is part of a corepressor complex and has direct interactions with class II HDACs that may be important for its molecular and behavioral consequences. And last, we propose the “molecular brake pad” hypothesis of HDAC function. The HDACs and associated corepressor complexes may function in neurons, in part, as “molecular brake pads.” HDACs are localized to promoters of active genes and act as a persistent clamp that requires strong activity-dependent signaling to temporarily release these complexes (or brake pads) to activate gene expression required for long-term memory formation. Thus, HDAC inhibition removes the “molecular brake pads” constraining the processes necessary for long-term memory and results in strong, persistent memory formation. PMID:21521655

High-Temperature Shape Memory Behavior of Semicrystalline Polyamide Thermosets.

PubMed

Li, Ming; Guan, Qingbao; Dingemans, Theo J

2018-05-21

We have explored semicrystalline poly(decamethylene terephthalamide) (PA 10T) based thermosets as single-component high-temperature (>200 °C) shape memory polymers (SMPs). The PA 10T thermosets were prepared from reactive thermoplastic precursors. Reactive phenylethynyl (PE) functionalities were either attached at the chain termini or placed as side groups along the polymer main chain. The shape fixation and recovery performance of the thermoset films were investigated using a rheometer in torsion mode. By controlling the M n of the reactive oligomers, or the PE concentration of the PE side-group functionalized copolyamides, we were able to design dual-shape memory PA 10T thermosets with a broad recovery temperature range of 227-285 °C. The thermosets based on the 1000 g mol -1 reactive PE precursor and the copolyamide with 15 mol % PE side groups show the highest fixation rate (99%) and recovery rate (≥90%). High temperature triple-shape memory behavior can be achieved as well when we use the melt transition ( T m ≥ 200 °C) and the glass transition ( T g = ∼125 °C) as the two switches. The recovery rate of the two recovery steps are highly dependent on the crystallinity of the thermosets and vary within a wide range of 74%-139% and 40-82% for the two steps, respectively. Reversible shape memory events could also be demonstrated when we perform a forward and backward deformation in a triple shape memory cycle. We also studied the angular recovery velocity as a function of temperature, which provides a thermokinematic picture of the shape recovery process and helps to program for desired shape memory behavior.

The effects of aging on emotion-induced modulations of source retrieval ERPs: evidence for valence biases.

PubMed

Newsome, Rachel N; Dulas, Michael R; Duarte, Audrey

2012-12-01

Many behavioral studies have shown that memory is enhanced for emotionally salient events across the lifespan. It has been suggested that this mnemonic boost may be observed for both age groups, particularly the old, in part because emotional information is retrieved with less effort than neutral information. Neuroimaging evidence suggests that inefficient retrieval processing (temporally delayed and attenuated) may contribute to age-related impairments in episodic memory for neutral events. It is not entirely clear whether emotional salience may reduce these age-related changes in neural activity associated with episodic retrieval for neutral events. Here, we investigated these ideas using event-related potentials (ERPs) to assess the neural correlates of successful source memory retrieval ("old-new effects") for neutral and emotional (negative and positive) images. Behavioral results showed that older adults demonstrated source memory impairments compared to the young but that both groups showed reduced source memory accuracy for negative compared to positive and neutral images; most likely due to an arousal-induced memory tradeoff for the negative images, which were subjectively more arousing than both positive and neutral images. ERP results showed that early onsetting old-new effects, between 100 and 300 ms, were observed for emotional but not neutral images in both age groups. Interestingly, these early effects were observed for negative items in the young and for positive items in the old. These ERP findings offer support for the idea that emotional events may be retrieved more automatically than neutral events across the lifespan. Furthermore, we suggest that very early retrieval mechanisms, possibly perceptual priming or familiarity, may underlie the negativity and positivity effects sometimes observed in the young and old, respectively, for various behavioral measures of attention and memory. Copyright © 2012 Elsevier Ltd. All rights reserved.

High-Temperature Shape Memory Behavior of Semicrystalline Polyamide Thermosets

PubMed Central

2018-01-01

We have explored semicrystalline poly(decamethylene terephthalamide) (PA 10T) based thermosets as single-component high-temperature (>200 °C) shape memory polymers (SMPs). The PA 10T thermosets were prepared from reactive thermoplastic precursors. Reactive phenylethynyl (PE) functionalities were either attached at the chain termini or placed as side groups along the polymer main chain. The shape fixation and recovery performance of the thermoset films were investigated using a rheometer in torsion mode. By controlling the Mn of the reactive oligomers, or the PE concentration of the PE side-group functionalized copolyamides, we were able to design dual-shape memory PA 10T thermosets with a broad recovery temperature range of 227–285 °C. The thermosets based on the 1000 g mol–1 reactive PE precursor and the copolyamide with 15 mol % PE side groups show the highest fixation rate (99%) and recovery rate (≥90%). High temperature triple-shape memory behavior can be achieved as well when we use the melt transition (Tm ≥ 200 °C) and the glass transition (Tg = ∼125 °C) as the two switches. The recovery rate of the two recovery steps are highly dependent on the crystallinity of the thermosets and vary within a wide range of 74%–139% and 40–82% for the two steps, respectively. Reversible shape memory events could also be demonstrated when we perform a forward and backward deformation in a triple shape memory cycle. We also studied the angular recovery velocity as a function of temperature, which provides a thermokinematic picture of the shape recovery process and helps to program for desired shape memory behavior. PMID:29742899

Poor comprehenders in the classroom: teacher ratings of behavior in children with poor reading comprehension and its relationship with individual differences in working memory.

PubMed

Pimperton, Hannah; Nation, Kate

2014-01-01

Differing etiological explanations have been proposed to account for poor comprehenders' difficulties with reading comprehension, with some researchers emphasizing working memory deficits and others arguing for oral language weaknesses playing a key causal role. The authors contrasted these two theoretical accounts using data obtained from direct measures of working memory and from teacher ratings of poor comprehenders' behavior in the classroom. At the group level, poor comprehenders showed weaknesses on verbal but not nonverbal working memory tasks, in keeping with the "language account." However, they also showed evidence of elevated levels of problem behaviors specifically associated with working memory deficits. Further analysis revealed that these group differences in working-memory-related problem behaviors were carried by a small subgroup of poor comprehenders who also displayed domain-general (verbal and nonverbal) working memory problems, argued to be reflective of "genuine" underlying working memory deficits.

Unconditioned- and Conditioned- Stimuli Induce Differential Memory Reconsolidation and β-AR-Dependent CREB Activation

PubMed Central

Huang, Bing; Zhu, Huiwen; Zhou, Yiming; Liu, Xing; Ma, Lan

2017-01-01

Consolidated long-term fear memories become labile and reconsolidated upon retrieval by the presentation of conditioned stimulus (CS) or unconditioned stimulus (US). Whether CS-retrieval or US-retrieval will trigger different memory reconsolidation processes is unknown. In this study, we introduced a sequential fear conditioning paradigm in which footshock (FS) was paired with two distinct sounds (CS-A and CS-B). The treatment with propranolol, a β-adrenergic receptor (β-AR) antagonist, after US (FS)-retrieval impaired freezing behavior evoked by either CS-A or CS-B. Betaxolol, a selective β1-AR antagonist, showed similar effects. However, propranolol treatment after retrieval by one CS (e.g., CS-A) only inhibited freezing behavior evoked by the same CS (i.e., CS-A), not the other CS (CS-B). These data suggest that β-AR is critically involved in reconsolidation of fear memory triggered by US- and CS-retrieval, whereas β-AR blockade after US-retrieval disrupts more CS-US associations than CS-retrieval does. Furthermore, significant CREB activation in almost the whole amygdala and hippocampus was observed after US-retrieval, but CS-retrieval only stimulated CREB activation in the lateral amygdala and the CA3 of hippocampus. In addition, propranolol treatment suppressed memory retrieval-induced CREB activation. These data indicate that US-retrieval activates more memory traces than CS-retrieval does, leading to memory reconsolidation of more CS-US associations. PMID:28848401

Bessel functions in mass action modeling of memories and remembrances

NASA Astrophysics Data System (ADS)

Freeman, Walter J.; Capolupo, Antonio; Kozma, Robert; Olivares del Campo, Andrés; Vitiello, Giuseppe

2015-10-01

Data from experimental observations of a class of neurological processes (Freeman K-sets) present functional distribution reproducing Bessel function behavior. We model such processes with couples of damped/amplified oscillators which provide time dependent representation of Bessel equation. The root loci of poles and zeros conform to solutions of K-sets. Some light is shed on the problem of filling the gap between the cellular level dynamics and the brain functional activity. Breakdown of time-reversal symmetry is related with the cortex thermodynamic features. This provides a possible mechanism to deduce lifetime of recorded memory.

Neurons in the Primate Medial Basal Forebrain Signal Combined Information about Reward Uncertainty, Value, and Punishment Anticipation

PubMed Central

Leopold, David A.; Hikosaka, Okihide

2015-01-01

It has been suggested that the basal forebrain (BF) exerts strong influences on the formation of memory and behavior. However, what information is used for the memory-behavior formation is unclear. We found that a population of neurons in the medial BF (medial septum and diagonal band of Broca) of macaque monkeys encodes a unique combination of information: reward uncertainty, expected reward value, anticipation of punishment, and unexpected reward and punishment. The results were obtained while the monkeys were expecting (often with uncertainty) a rewarding or punishing outcome during a Pavlovian procedure, or unexpectedly received an outcome outside the procedure. In vivo anterograde tracing using manganese-enhanced MRI suggested that the major recipient of these signals is the intermediate hippocampal formation. Based on these findings, we hypothesize that the medial BF identifies various contexts and outcomes that are critical for memory processing in the hippocampal formation. PMID:25972172

Nonlinear Developmental trajectory of fear learning and memory

PubMed Central

King, Elizabeth C.; Pattwell, Siobhan S.; Sun, Alice; Glatt, Charles E.; Lee, Francis S.

2013-01-01

The transition into and out of adolescence represents a unique developmental period during which neuronal circuits are particularly susceptible to modification by experience. Adolescence is associated with an increased incidence of anxiety disorders in humans,1–3 and an estimated 75% of adults with fear-related disorders met diagnostic criteria as children and adolescents.4,5 Conserved neural circuitry between rodents and humans has facilitated neurodevelopmental studies of behavioral and molecular processes associated with fear learning and memory, which lie at the heart of many anxiety disorders. Here, we review the non-linear developmental aspects of fear learning and memory during a transition period into and out of adolescence and provide a discussion of the molecular mechanisms that may underlie these alterations in behavior. We provide a model that may help to inform novel treatment strategies for children and adolescents with fear-related disorders. PMID:24176014

Variability in the impairment of recognition memory in patients with frontal lobe lesions.

PubMed

Bastin, Christine; Van der Linden, Martial; Lekeu, Françoise; Andrés, Pilar; Salmon, Eric

2006-10-01

Fourteen patients with frontal lobe lesions and 14 normal subjects were tested on a recognition memory task that required discriminating between target words, new words that are synonyms of the targets and unrelated distractors. A deficit was found in 12 of the patients. Moreover, three different patterns of recognition impairment were identified: (I) poor memory for targets, (II) normal hits but increased false recognitions for both types of distractors, (III) normal hit rates, but increased false recognitions for synonyms only. Differences in terms of location of the damage and behavioral characteristics between these subgroups were examined. An encoding deficit was proposed to explain the performance of patients in subgroup I. The behavioral patterns of the patients in subgroups II and III could be interpreted as deficient post-retrieval verification processes and an inability to recollect item-specific information, respectively.

Presynaptic learning and memory with a persistent firing neuron and a habituating synapse: a model of short term persistent habituation.

PubMed

Ramanathan, Kiruthika; Ning, Ning; Dhanasekar, Dhiviya; Li, Guoqi; Shi, Luping; Vadakkepat, Prahlad

2012-08-01

Our paper explores the interaction of persistent firing axonal and presynaptic processes in the generation of short term memory for habituation. We first propose a model of a sensory neuron whose axon is able to switch between passive conduction and persistent firing states, thereby triggering short term retention to the stimulus. Then we propose a model of a habituating synapse and explore all nine of the behavioral characteristics of short term habituation in a two neuron circuit. We couple the persistent firing neuron to the habituation synapse and investigate the behavior of short term retention of habituating response. Simulations show that, depending on the amount of synaptic resources, persistent firing either results in continued habituation or maintains the response, both leading to longer recovery times. The effectiveness of the model as an element in a bio-inspired memory system is discussed.

[Hypoxia and memory. Specific features of nootropic agents effects and their use].

PubMed

Voronina, T A

2000-01-01

Hypoxia and hypoxic adaptation are powerful factors of controlling memory and behavior processes. Acute hypoxia exerts a differential impact on different deficits of mnestic and cognitive functions. Instrumental reflexes of active and passive avoidance, negative learning, behavior with a change in the stereotype of learning are more greatly damaged. Memory with spatial and visual differentiation and their rearrangement change to a lesser extent and conditional reflexes are not deranged. In this contract, altitude hypoxic adaptation enhances information fixation and increases the degree and duration of retention of temporary relations. Nootropic agents with an antihypoxic action exert a marked effect on hypoxia-induced cognitive and memory disorders and the magnitude of this effect depends on the ration of proper nootropic to antihypoxic components in the spectrum of the drugs' pharmacological activity. The agents that combine a prevailing antiamnestic effect and a marked and moderate antihypoxic action (mexidole, nooglutil, pyracetam, beglymin, etc.) are most effective in eliminating different hypoxia-induced cognitive and memory disorders, nootropic drugs that have a pronounced antiamnestic activity (centrophenoxine, etc.) and no antihypoxic component also restore the main types of mnestic disorders after hypoxia, but to a lesser extent.

Cellular dynamical mechanisms for encoding the time and place of events along spatiotemporal trajectories in episodic memory.

PubMed

Hasselmo, Michael E; Giocomo, Lisa M; Brandon, Mark P; Yoshida, Motoharu

2010-12-31

Understanding the mechanisms of episodic memory requires linking behavioral data and lesion effects to data on the dynamics of cellular membrane potentials and population interactions within brain regions. Linking behavior to specific membrane channels and neurochemicals has implications for therapeutic applications. Lesions of the hippocampus, entorhinal cortex and subcortical nuclei impair episodic memory function in humans and animals, and unit recording data from these regions in behaving animals indicate episodic memory processes. Intracellular recording in these regions demonstrates specific cellular properties including resonance, membrane potential oscillations and bistable persistent spiking that could underlie the encoding and retrieval of episodic trajectories. A model presented here shows how intrinsic dynamical properties of neurons could mediate the encoding of episodic memories as complex spatiotemporal trajectories. The dynamics of neurons allow encoding and retrieval of unique episodic trajectories in multiple continuous dimensions including temporal intervals, personal location, the spatial coordinates and sensory features of perceived objects and generated actions, and associations between these elements. The model also addresses how cellular dynamics could underlie unit firing data suggesting mechanisms for coding continuous dimensions of space, time, sensation and action. Copyright © 2010 Elsevier B.V. All rights reserved.

Similarity to the Self Affects Memory for Impressions of Others

PubMed Central

Leshikar, Eric D.; Gutchess, Angela H.

2017-01-01

The present studies investigated whether similarity to the self influenced memory for impressions of others. We predicted that similarity to the self would facilitate impression memory for others, paralleling the self-reference effect found when information is processed relative to the self. We were interested in how the initial valence of the impression, whether positive or negative, affected impression memory. Across two experiments, participants formed impressions while viewing faces paired with traits and behaviors. After recognition, participants rated the self-descriptiveness of the studied traits allowing impression memory to be sorted into high-, medium-, and low-self-similarity. For positive impressions, similar others were remembered better than dissimilar others. For negative impressions, similar others were remembered more poorly than dissimilar others. These results illustrate that similarity to the self has multifaceted effects on person memory, leading to memory enhancement in the case of people given positive impressions, but reducing memory for people associated with negative impressions. PMID:28936392

The infamous among us: Enhanced reputational memory for uncooperative ingroup members.

PubMed

Hechler, Stefanie; Neyer, Franz J; Kessler, Thomas

2016-12-01

People remember uncooperative individuals better than cooperative ones. We hypothesize that this is particularly true when uncooperative individuals belong to one's ingroup, as their behavior violates positive expectations. Two studies examined the effect of minimal group categorization on reputational memory of the social behavior of particular ingroup and outgroup members. We manipulated uncooperative behavior as the unfair sharing of resources with ingroup members (Study 1), or as descriptions of cheating (Study 2). Participants evaluated several uncooperative and cooperative (and neutral) ingroup and outgroup members. In a surprise memory test, they had to recognize target faces and recall their behavior. We disentangled face recognition, reputational memory, and guessing biases with multinomial models of source monitoring. The results show enhanced reputational memory for uncooperative ingroup members, but not uncooperative outgroup members. In contrast, guessing behavior indicated that participants assumed more ingroup cooperation than outgroup cooperation. Our findings integrate prior research on memory for uncooperative person behavior and person memory in group contexts. We suggest that the ability to remember the uncooperative amidst the supposedly cooperative ingroup could stabilize intragroup cooperation. Copyright © 2016 Elsevier B.V. All rights reserved.

A Unified Dynamic Model for Learning, Replay, and Sharp-Wave/Ripples.

PubMed

Jahnke, Sven; Timme, Marc; Memmesheimer, Raoul-Martin

2015-12-09

Hippocampal activity is fundamental for episodic memory formation and consolidation. During phases of rest and sleep, it exhibits sharp-wave/ripple (SPW/R) complexes, which are short episodes of increased activity with superimposed high-frequency oscillations. Simultaneously, spike sequences reflecting previous behavior, such as traversed trajectories in space, are replayed. Whereas these phenomena are thought to be crucial for the formation and consolidation of episodic memory, their neurophysiological mechanisms are not well understood. Here we present a unified model showing how experience may be stored and thereafter replayed in association with SPW/Rs. We propose that replay and SPW/Rs are tightly interconnected as they mutually generate and support each other. The underlying mechanism is based on the nonlinear dendritic computation attributable to dendritic sodium spikes that have been prominently found in the hippocampal regions CA1 and CA3, where SPW/Rs and replay are also generated. Besides assigning SPW/Rs a crucial role for replay and thus memory processing, the proposed mechanism also explains their characteristic features, such as the oscillation frequency and the overall wave form. The results shed a new light on the dynamical aspects of hippocampal circuit learning. During phases of rest and sleep, the hippocampus, the "memory center" of the brain, generates intermittent patterns of strongly increased overall activity with high-frequency oscillations, the so-called sharp-wave/ripples. We investigate their role in learning and memory processing. They occur together with replay of activity sequences reflecting previous behavior. Developing a unifying computational model, we propose that both phenomena are tightly linked, by mutually generating and supporting each other. The underlying mechanism depends on nonlinear amplification of synchronous inputs that has been prominently found in the hippocampus. Besides assigning sharp-wave/ripples a crucial role for replay generation and thus memory processing, the proposed mechanism also explains their characteristic features, such as the oscillation frequency and the overall wave form. Copyright © 2015 the authors 0270-6474/15/3516236-23$15.00/0.

Variation in Dopamine D2 and Serotonin 5-HT2A Receptor Genes is Associated with Working Memory Processing and Response to Treatment with Antipsychotics

PubMed Central

Blasi, Giuseppe; Selvaggi, Pierluigi; Fazio, Leonardo; Antonucci, Linda Antonella; Taurisano, Paolo; Masellis, Rita; Romano, Raffaella; Mancini, Marina; Zhang, Fengyu; Caforio, Grazia; Popolizio, Teresa; Apud, Jose; Weinberger, Daniel R; Bertolino, Alessandro

2015-01-01

Dopamine D2 and serotonin 5-HT2A receptors contribute to modulate prefrontal cortical physiology and response to treatment with antipsychotics in schizophrenia. Similarly, functional variation in the genes encoding these receptors is also associated with these phenotypes. In particular, the DRD2 rs1076560 T allele predicts a lower ratio of expression of D2 short/long isoforms, suboptimal working memory processing, and better response to antipsychotic treatment compared with the G allele. Furthermore, the HTR2A T allele is associated with lower 5-HT2A expression, impaired working memory processing, and poorer response to antipsychotics compared with the C allele. Here, we investigated in healthy subjects whether these functional polymorphisms have a combined effect on prefrontal cortical physiology and related cognitive behavior linked to schizophrenia as well as on response to treatment with second-generation antipsychotics in patients with schizophrenia. In a total sample of 620 healthy subjects, we found that subjects with the rs1076560 T and rs6314 T alleles have greater fMRI prefrontal activity during working memory. Similar results were obtained within the attentional domain. Also, the concomitant presence of the rs1076560 T/rs6314 T alleles also predicted lower behavioral accuracy during working memory. Moreover, we found that rs1076560 T carrier/rs6314 CC individuals had better responses to antipsychotic treatment in two independent samples of patients with schizophrenia (n=63 and n=54, respectively), consistent with the previously reported separate effects of these genotypes. These results indicate that DRD2 and HTR2A genetic variants together modulate physiological prefrontal efficiency during working memory and also modulate the response to antipsychotics. Therefore, these results suggest that further exploration is needed to better understand the clinical consequences of these genotype–phenotype relationships. PMID:25563748

Variation in Dopamine D2 and Serotonin 5-HT2A Receptor Genes is Associated with Working Memory Processing and Response to Treatment with Antipsychotics.

PubMed

Blasi, Giuseppe; Selvaggi, Pierluigi; Fazio, Leonardo; Antonucci, Linda Antonella; Taurisano, Paolo; Masellis, Rita; Romano, Raffaella; Mancini, Marina; Zhang, Fengyu; Caforio, Grazia; Popolizio, Teresa; Apud, Jose; Weinberger, Daniel R; Bertolino, Alessandro

2015-06-01

Dopamine D2 and serotonin 5-HT2A receptors contribute to modulate prefrontal cortical physiology and response to treatment with antipsychotics in schizophrenia. Similarly, functional variation in the genes encoding these receptors is also associated with these phenotypes. In particular, the DRD2 rs1076560 T allele predicts a lower ratio of expression of D2 short/long isoforms, suboptimal working memory processing, and better response to antipsychotic treatment compared with the G allele. Furthermore, the HTR2A T allele is associated with lower 5-HT2A expression, impaired working memory processing, and poorer response to antipsychotics compared with the C allele. Here, we investigated in healthy subjects whether these functional polymorphisms have a combined effect on prefrontal cortical physiology and related cognitive behavior linked to schizophrenia as well as on response to treatment with second-generation antipsychotics in patients with schizophrenia. In a total sample of 620 healthy subjects, we found that subjects with the rs1076560 T and rs6314 T alleles have greater fMRI prefrontal activity during working memory. Similar results were obtained within the attentional domain. Also, the concomitant presence of the rs1076560 T/rs6314 T alleles also predicted lower behavioral accuracy during working memory. Moreover, we found that rs1076560 T carrier/rs6314 CC individuals had better responses to antipsychotic treatment in two independent samples of patients with schizophrenia (n=63 and n=54, respectively), consistent with the previously reported separate effects of these genotypes. These results indicate that DRD2 and HTR2A genetic variants together modulate physiological prefrontal efficiency during working memory and also modulate the response to antipsychotics. Therefore, these results suggest that further exploration is needed to better understand the clinical consequences of these genotype-phenotype relationships.

Serotonin Control of Thermotaxis Memory Behavior in Nematode Caenorhabditis elegans

PubMed Central

Guo, Yuling; Wang, Daoyong; Li, Chaojun; Wang, Dayong

2013-01-01

Caenorhabditis elegans is as an ideal model system for the study of mechanisms underlying learning and memory. In the present study, we employed C. elegans assay system of thermotaxis memory to investigate the possible role of serotonin neurotransmitter in memory control. Our data showed that both mutations of tph-1, bas-1, and cat-4 genes, required for serotonin synthesis, and mutations of mod-5 gene, encoding a serotonin reuptake transporter, resulted in deficits in thermotaxis memory behavior. Exogenous treatment with serotonin effectively recovered the deficits in thermotaxis memory of tph-1 and bas-1 mutants to the level of wild-type N2. Neuron-specific activity assay of TPH-1 suggests that serotonin might regulate the thermotaxis memory behavior by release from the ADF sensory neurons. Ablation of ADF sensory neurons by expressing a cell-death activator gene egl-1 decreased the thermotaxis memory, whereas activation of ADF neurons by expression of a constitutively active protein kinase C homologue (pkc-1(gf)) increased the thermotaxis memory and rescued the deficits in thermotaxis memory in tph-1 mutants. Moreover, serotonin released from the ADF sensory neurons might act through the G-protein-coupled serotonin receptors of SER-4 and SER-7 to regulate the thermotaxis memory behavior. Genetic analysis implies that serotonin might further target the insulin signaling pathway to regulate the thermotaxis memory behavior. Thus, our results suggest the possible crucial role of serotonin and ADF sensory neurons in thermotaxis memory control in C. elegans. PMID:24223727

Sound Asleep: Processing and Retention of Slow Oscillation Phase-Targeted Stimuli

PubMed Central

Cox, Roy; Korjoukov, Ilia; de Boer, Marieke; Talamini, Lucia M.

2014-01-01

The sleeping brain retains some residual information processing capacity. Although direct evidence is scarce, a substantial literature suggests the phase of slow oscillations during deep sleep to be an important determinant for stimulus processing. Here, we introduce an algorithm for predicting slow oscillations in real-time. Using this approach to present stimuli directed at both oscillatory up and down states, we show neural stimulus processing depends importantly on the slow oscillation phase. During ensuing wakefulness, however, we did not observe differential brain or behavioral responses to these stimulus categories, suggesting no enduring memories were formed. We speculate that while simpler forms of learning may occur during sleep, neocortically based memories are not readily established during deep sleep. PMID:24999803

Sound asleep: processing and retention of slow oscillation phase-targeted stimuli.

PubMed

Cox, Roy; Korjoukov, Ilia; de Boer, Marieke; Talamini, Lucia M

2014-01-01

The sleeping brain retains some residual information processing capacity. Although direct evidence is scarce, a substantial literature suggests the phase of slow oscillations during deep sleep to be an important determinant for stimulus processing. Here, we introduce an algorithm for predicting slow oscillations in real-time. Using this approach to present stimuli directed at both oscillatory up and down states, we show neural stimulus processing depends importantly on the slow oscillation phase. During ensuing wakefulness, however, we did not observe differential brain or behavioral responses to these stimulus categories, suggesting no enduring memories were formed. We speculate that while simpler forms of learning may occur during sleep, neocortically based memories are not readily established during deep sleep.

Nitrogen-doped partially reduced graphene oxide rewritable nonvolatile memory.

PubMed

Seo, Sohyeon; Yoon, Yeoheung; Lee, Junghyun; Park, Younghun; Lee, Hyoyoung

2013-04-23

As memory materials, two-dimensional (2D) carbon materials such as graphene oxide (GO)-based materials have attracted attention due to a variety of advantageous attributes, including their solution-processability and their potential for highly scalable device fabrication for transistor-based memory and cross-bar memory arrays. In spite of this, the use of GO-based materials has been limited, primarily due to uncontrollable oxygen functional groups. To induce the stable memory effect by ionic charges of a negatively charged carboxylic acid group of partially reduced graphene oxide (PrGO), a positively charged pyridinium N that served as a counterion to the negatively charged carboxylic acid was carefully introduced on the PrGO framework. Partially reduced N-doped graphene oxide (PrGODMF) in dimethylformamide (DMF) behaved as a semiconducting nonvolatile memory material. Its optical energy band gap was 1.7-2.1 eV and contained a sp2 C═C framework with 45-50% oxygen-functionalized carbon density and 3% doped nitrogen atoms. In particular, rewritable nonvolatile memory characteristics were dependent on the proportion of pyridinum N, and as the proportion of pyridinium N atom decreased, the PrGODMF film lost memory behavior. Polarization of charged PrGODMF containing pyridinium N and carboxylic acid under an electric field produced N-doped PrGODMF memory effects that followed voltage-driven rewrite-read-erase-read processes.

Structural Variation within the Amygdala and Ventromedial Prefrontal Cortex Predicts Memory for Impressions in Older Adults

PubMed Central

Cassidy, Brittany S.; Gutchess, Angela H.

2012-01-01

Research has shown that lesions to regions involved in social and emotional cognition disrupt socioemotional processing and memory. We investigated how structural variation of regions involved in socioemotional memory [ventromedial prefrontal cortex (vmPFC), amygdala], as opposed to a region implicated in explicit memory (hippocampus), affected memory for impressions in young and older adults. Anatomical MRI scans for 15 young and 15 older adults were obtained and reconstructed to gather information about cortical thickness and subcortical volume. Young adults had greater amygdala and hippocampus volumes than old, and thicker left vmPFC than old, although right vmPFC thickness did not differ across the age groups. Participants formed behavior-based impressions and responded to interpersonally meaningful, social but interpersonally irrelevant, or non-social prompts, and completed a memory test. Results showed that greater left amygdala volume predicted enhanced overall memory for impressions in older but not younger adults. Increased right vmPFC thickness in older, but not younger, adults correlated with enhanced memory for impressions formed in the interpersonally meaningful context. Hippocampal volume was not predictive of social memory in young or older adults. These findings demonstrate the importance of structural variation in regions linked to socioemotional processing in the retention of impressions with age, and suggest that the amygdala and vmPFC play integral roles when encoding and retrieving social information. PMID:22973250

The origins of repetitive thought in rumination: separating cognitive style from deficits in inhibitory control over memory.

PubMed

Fawcett, Jonathan M; Benoit, Roland G; Gagnepain, Pierre; Salman, Amna; Bartholdy, Savani; Bradley, Caroline; Chan, Daniel K Y; Roche, Ayesha; Brewin, Chris R; Anderson, Michael C

2015-06-01

Rumination is a major contributor to the maintenance of affective disorders and has been linked to memory control deficits. However, ruminators often report intentionally engaging in repetitive thought due to its perceived benefits. Deliberate re-processing may lead to the appearance of a memory control deficit that is better explained as a difference in cognitive style. Ninety-six undergraduate students volunteered to take part in a direct-suppression variant of the Think/No-Think paradigm after which they completed self-report measures of rumination and the degree to which they deliberately re-processed the to-be-suppressed items. We demonstrate a relation between rumination and impaired suppression-induced forgetting. This relation is robust even when controlling for deliberate re-processing of the to-be-suppressed items, a behavior itself related to both rumination and suppression. Therefore, whereas conscious fixation on to-be-suppressed items reduced memory suppression, it did not fully account for the relation between rumination and memory suppression. The current experiment employed a retrospective measure of deliberate re-processing in the context of an unscreened university sample; future research might therefore generalize our findings using an online measure of deliberate re-processing or within a clinical population. We provide evidence that deliberate re-processing accounts for some--but not all--of the relation between rumination and suppression-induced forgetting. The present findings, observed in a paradigm known to engage top-down inhibitory modulation of mnemonic processing, provide the most theoretically focused evidence to date for the existence of a memory control deficit in rumination. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

Dorsal and ventral working memory-related brain areas support distinct processes in contextual cueing.

PubMed

Manginelli, Angela A; Baumgartner, Florian; Pollmann, Stefan

2013-02-15

Behavioral evidence suggests that the use of implicitly learned spatial contexts for improved visual search may depend on visual working memory resources. Working memory may be involved in contextual cueing in different ways: (1) for keeping implicitly learned working memory contents available during search or (2) for the capture of attention by contexts retrieved from memory. We mapped brain areas that were modulated by working memory capacity. Within these areas, activation was modulated by contextual cueing along the descending segment of the intraparietal sulcus, an area that has previously been related to maintenance of explicit memories. Increased activation for learned displays, but not modulated by the size of contextual cueing, was observed in the temporo-parietal junction area, previously associated with the capture of attention by explicitly retrieved memory items, and in the ventral visual cortex. This pattern of activation extends previous research on dorsal versus ventral stream functions in memory guidance of attention to the realm of attentional guidance by implicit memory. Copyright © 2012 Elsevier Inc. All rights reserved.

Neural activations associated with feedback and retrieval success

NASA Astrophysics Data System (ADS)

Wiklund-Hörnqvist, Carola; Andersson, Micael; Jonsson, Bert; Nyberg, Lars

2017-11-01

There is substantial behavioral evidence for a phenomenon commonly called "the testing effect", i.e. superior memory performance after repeated testing compared to re-study of to-be-learned materials. However, considerably less is known about the underlying neuro-cognitive processes that are involved in the initial testing phase, and thus underlies the actual testing effect. Here, we investigated functional brain activity related to test-enhanced learning with feedback. Subjects learned foreign vocabulary across three consecutive tests with correct-answer feedback. Functional brain-activity responses were analyzed in relation to retrieval and feedback events, respectively. Results revealed up-regulated activity in fronto-striatal regions during the first successful retrieval, followed by a marked reduction in activity as a function of improved learning. Whereas feedback improved behavioral performance across consecutive tests, feedback had a negligable role after the first successful retrieval for functional brain-activity modulations. It is suggested that the beneficial effects of test-enhanced learning is regulated by feedback-induced updating of memory representations, mediated via the striatum, that might underlie the stabilization of memory commonly seen in behavioral studies of the testing effect.

Episodic memory and self-reference via semantic autobiographical memory: insights from an fMRI study in younger and older adults.

PubMed

Kalenzaga, Sandrine; Sperduti, Marco; Anssens, Adèle; Martinelli, Penelope; Devauchelle, Anne-Dominique; Gallarda, Thierry; Delhommeau, Marion; Lion, Stéphanie; Amado, Isabelle; Krebs, Marie-Odile; Oppenheim, Catherine; Piolino, Pascale

2014-01-01

Self-referential processing relies mainly on the medial prefrontal cortex (MPFC) and enhances memory encoding (i.e., Self-Reference Effect, SRE) as it improves the accuracy and richness of remembering in both young and older adults. However, studies on age-related changes in the neural correlates of the SRE on the subjective (i.e., autonoetic consciousness) and the objective (i.e., source memory) qualitative features of episodic memory are lacking. In the present fMRI study, we compared the effects of a self-related (semantic autobiographical memory task) and a non self-related (general semantic memory task) encoding condition on subsequent episodic memory retrieval. We investigated encoding-related activity during each condition in two groups of 19 younger and 16 older adults. Behaviorally, the SRE improved subjective memory performance in both groups but objective memory only in young adults. At the neural level, a direct comparison between self-related and non self-related conditions revealed that SRE mainly activated the cortical midline system, especially the MPFC, in both groups. Additionally, in older adults and regardless of the condition, greater activity was found in a fronto-parietal network. Overall, correlations were noted between source memory performance and activity in the MPFC (irrespective of age) and visual areas (mediated by age). Thus, the present findings expand evidence of the role of the MPFC in self-referential processing in the context of source memory benefit in both young and older adults using incidental encoding via semantic autobiographical memory. However, our finding suggests that its role is less effective in aging.

Episodic memory and self-reference via semantic autobiographical memory: insights from an fMRI study in younger and older adults

PubMed Central

Kalenzaga, Sandrine; Sperduti, Marco; Anssens, Adèle; Martinelli, Penelope; Devauchelle, Anne-Dominique; Gallarda, Thierry; Delhommeau, Marion; Lion, Stéphanie; Amado, Isabelle; Krebs, Marie-Odile; Oppenheim, Catherine; Piolino, Pascale

2015-01-01

Self-referential processing relies mainly on the medial prefrontal cortex (MPFC) and enhances memory encoding (i.e., Self-Reference Effect, SRE) as it improves the accuracy and richness of remembering in both young and older adults. However, studies on age-related changes in the neural correlates of the SRE on the subjective (i.e., autonoetic consciousness) and the objective (i.e., source memory) qualitative features of episodic memory are lacking. In the present fMRI study, we compared the effects of a self-related (semantic autobiographical memory task) and a non self-related (general semantic memory task) encoding condition on subsequent episodic memory retrieval. We investigated encoding-related activity during each condition in two groups of 19 younger and 16 older adults. Behaviorally, the SRE improved subjective memory performance in both groups but objective memory only in young adults. At the neural level, a direct comparison between self-related and non self-related conditions revealed that SRE mainly activated the cortical midline system, especially the MPFC, in both groups. Additionally, in older adults and regardless of the condition, greater activity was found in a fronto-parietal network. Overall, correlations were noted between source memory performance and activity in the MPFC (irrespective of age) and visual areas (mediated by age). Thus, the present findings expand evidence of the role of the MPFC in self-referential processing in the context of source memory benefit in both young and older adults using incidental encoding via semantic autobiographical memory. However, our finding suggests that its role is less effective in aging. PMID:25628546

Limited capacity of working memory in unihemispheric random walks implies conceivable slow dispersal.

PubMed

Wei, Kun; Zhong, Suchuan

2017-08-01

Phenomenologically inspired by dolphins' unihemispheric sleep, we introduce a minimal model for random walks with physiological memory. The physiological memory consists of long-term memory which includes unconscious implicit memory and conscious explicit memory, and working memory which serves as a multi-component system for integrating, manipulating and managing short-term storage. The model assumes that the sleeping state allows retrievals of episodic objects merely from the episodic buffer where these memory objects are invoked corresponding to the ambient objects and are thus object-oriented, together with intermittent but increasing use of implicit memory in which decisions are unconsciously picked up from historical time series. The process of memory decay and forgetting is constructed in the episodic buffer. The walker's risk attitude, as a product of physiological heuristics according to the performance of objected-oriented decisions, is imposed on implicit memory. The analytical results of unihemispheric random walks with the mixture of object-oriented and time-oriented memory, as well as the long-time behavior which tends to the use of implicit memory, are provided, indicating the common sense that a conservative risk attitude is inclinable to slow movement.

Epigenetic mechanisms: critical contributors to long-term memory formation.

PubMed

Lubin, Farah D; Gupta, Swati; Parrish, R Ryley; Grissom, Nicola M; Davis, Robin L

2011-12-01

Recent advances in chromatin biology have identified a role for epigenetic mechanisms in the regulation of neuronal gene expression changes, a necessary process for proper synaptic plasticity and memory formation. Experimental evidence for dynamic chromatin remodeling influencing gene transcription in postmitotic neurons grew from initial reports describing posttranslational modifications of histones, including phosphorylation and acetylation occurring in various brain regions during memory consolidation. An accumulation of recent studies, however, has also highlighted the importance of other epigenetic modifications, such as DNA methylation and histone methylation, as playing a role in memory formation. This present review examines learning-induced gene transcription by chromatin remodeling underlying long-lasting changes in neurons, with direct implications for the study of epigenetic mechanisms in long-term memory formation and behavior. Furthermore, the study of epigenetic gene regulation, in conjunction with transcription factor activation, can provide complementary lines of evidence to further understanding transcriptional mechanisms subserving memory storage.

An Electrophysiological Signature of Unconscious Recognition Memory

PubMed Central

Voss, Joel L.; Paller, Ken A.

2009-01-01

Contradicting the common assumption that accurate recognition reflects explicit-memory processing, we describe evidence for recognition lacking two hallmark explicit-memory features: awareness of memory retrieval and facilitation by attentive encoding. Kaleidoscope images were encoded in conjunction with an attentional diversion and subsequently recognized more accurately than those encoded without diversion. Confidence in recognition was superior following attentive encoding, though recognition was remarkably accurate when people claimed to be unaware of memory retrieval. This “implicit recognition” was associated with frontal-occipital negative brain potentials at 200-400 ms post-stimulus-onset, which were spatially and temporally distinct from positive brain potentials corresponding to explicit recollection and familiarity. This dissociation between behavioral and electrophysiological characteristics of “implicit recognition” versus explicit recognition indicates that a neurocognitive mechanism with properties similar to those that produce implicit memory can be operative in standard recognition tests. People can accurately discriminate repeat stimuli from new stimuli without necessarily knowing it. PMID:19198606

Aged-related Neural Changes during Memory Conjunction Errors

PubMed Central

Giovanello, Kelly S.; Kensinger, Elizabeth A.; Wong, Alana T.; Schacter, Daniel L.

2013-01-01

Human behavioral studies demonstrate that healthy aging is often accompanied by increases in memory distortions or errors. Here we used event-related functional MRI to examine the neural basis of age-related memory distortions. We utilized the memory conjunction error paradigm, a laboratory procedure known to elicit high levels of memory errors. For older adults, right parahippocampal gyrus showed significantly greater activity during false than during accurate retrieval. We observed no regions in which activity was greater during false than during accurate retrieval for young adults. Young adults, however, showed significantly greater activity than old adults during accurate retrieval in right hippocampus. By contrast, older adults demonstrated greater activity than young adults during accurate retrieval in right inferior and middle prefrontal cortex. These data are consistent with the notion that age-related memory conjunction errors arise from dysfunction of hippocampal system mechanisms, rather than impairments in frontally-mediated monitoring processes. PMID:19445606

Distributed representations in memory: Insights from functional brain imaging

PubMed Central

Rissman, Jesse; Wagner, Anthony D.

2015-01-01

Forging new memories for facts and events, holding critical details in mind on a moment-to-moment basis, and retrieving knowledge in the service of current goals all depend on a complex interplay between neural ensembles throughout the brain. Over the past decade, researchers have increasingly leveraged powerful analytical tools (e.g., multi-voxel pattern analysis) to decode the information represented within distributed fMRI activity patterns. In this review, we discuss how these methods can sensitively index neural representations of perceptual and semantic content, and how leverage on the engagement of distributed representations provides unique insights into distinct aspects of memory-guided behavior. We emphasize that, in addition to characterizing the contents of memories, analyses of distributed patterns shed light on the processes that influence how information is encoded, maintained, or retrieved, and thus inform memory theory. We conclude by highlighting open questions about memory that can be addressed through distributed pattern analyses. PMID:21943171

Restoration of fMRI Decodability Does Not Imply Latent Working Memory States

PubMed Central

Schneegans, Sebastian; Bays, Paul M.

2018-01-01

Recent imaging studies have challenged the prevailing view that working memory is mediated by sustained neural activity. Using machine learning methods to reconstruct memory content, these studies found that previously diminished representations can be restored by retrospective cueing or other forms of stimulation. These findings have been interpreted as evidence for an activity-silent working memory state that can be reactivated dependent on task demands. Here, we test the validity of this conclusion by formulating a neural process model of working memory based on sustained activity and using this model to emulate a spatial recall task with retrocueing. The simulation reproduces both behavioral and fMRI results previously taken as evidence for latent states, in particular the restoration of spatial reconstruction quality following an informative cue. Our results demonstrate that recovery of the decodability of an imaging signal does not provide compelling evidence for an activity-silent working memory state. PMID:28820674

Fear memory consolidation in sleep requires protein kinase A.

PubMed

Cho, Jiyeon; Sypniewski, Krzysztof A; Arai, Shoko; Yamada, Kazuo; Ogawa, Sonoko; Pavlides, Constantine

2018-05-01

It is well established that protein kinase A (PKA) is involved in hippocampal dependent memory consolidation. Sleep is also known to play an important role in this process. However, whether sleep-dependent memory consolidation involves PKA activation has not been clearly determined. Using behavioral observation, animals were categorized into sleep and awake groups. We show that intrahippocampal injections of the PKA inhibitor Rp-cAMPs in post-contextual fear conditioning sleep produced a suppression of long-term fear memory, while injections of Rp-cAMPs during an awake state, at a similar time point, had no effect. In contrast, injections of the PKA activator Sp-cAMPs in awake state, rescued sleep deprivation-induced memory impairments. These results suggest that following learning, PKA activation specifically in sleep is required for the consolidation of long-term memory. © 2018 Cho et al.; Published by Cold Spring Harbor Laboratory Press.

Processes Contributing to the Maintenance of Flying Phobia: A Narrative Review

PubMed Central

Clark, Gavin I.; Rock, Adam J.

2016-01-01

Flying phobia is a highly prevalent anxiety disorder, which causes sufferers significant distress and life interference. The processes which maintain flying phobia remain poorly understood. A systematic search of the literature was performed to identify what research has been conducted into the processes which may be involved in the fear of flying and whether processes which are believed to maintain other anxiety disorder diagnoses have been investigated in flying phobia. The results of the literature review are presented and related to existing cognitive behavioral theory and research. The results indicate that little research has been conducted into a number of areas considered important in the wider cognitive behavioral literature on anxiety disorders: namely attention, mental imagery, memory, worry, and safety-seeking behaviors. The review proposes a hypothetical model, derived from cognitive behavioral theory, for the processes which may be involved in maintaining flying phobia, and considers a number of areas for future research. PMID:27313550

A Nexus Model of the Temporal-Parietal Junction

PubMed Central

Carter, R. McKell; Huettel, Scott A.

2013-01-01

The temporal-parietal junction (TPJ) has been proposed to support either specifically social functions or non-specific processes of cognition like memory and attention. To account for diverse prior findings, we propose a Nexus Model for TPJ function: overlap of basic processes produces novel secondary functions at their convergence. We present meta-analytic evidence that is consistent with the anatomical convergence of attention, memory, language, and social processing in the TPJ – leading to a higher-order role in the creation of a social context for behavior. The Nexus Model accounts for recent examples of TPJ contributions specifically to decision making in a social context, and it provides a potential reconciliation for competing claims about TPJ function. PMID:23790322

Mass Spectrometry-based Approaches to Understand the Molecular Basis of Memory

NASA Astrophysics Data System (ADS)

Pontes, Arthur; de Sousa, Marcelo

2016-10-01

The central nervous system is responsible for an array of cognitive functions such as memory, learning, language and attention. These processes tend to take place in distinct brain regions; yet, they need to be integrated to give rise to adaptive or meaningful behavior. Since cognitive processes result from underlying cellular and molecular changes, genomics and transcriptomics assays have been applied to human and animal models to understand such events. Nevertheless, genes and RNAs are not the end products of most biological functions. In order to gain further insights toward the understanding of brain processes, the field of proteomics has been of increasing importance in the past years. Advancements in liquid chromatography-tandem mass spectrometry (LC-MS/MS) have enable the identification and quantification of thousand of proteins with high accuracy and sensitivity, fostering a revolution in the neurosciences. Herein, we review the molecular bases of explicit memory in the hippocampus. We outline the principles of mass spectrometry (MS)-based proteomics, highlighting the use of this analytical tool to study memory formation. In addition, we discuss MS-based targeted approaches as the future of protein analysis.

Behavioral and Event-Related-Potential Correlates of Processing Congruent and Incongruent Self-Relevant Information

ERIC Educational Resources Information Center

Clark, Sheri L.

2013-01-01

People want to be viewed by others as they view themselves. Being confronted with self-relevant information that is either congruent or incongruent with one's self-view has been shown to differentially affect subsequent behavior, memory for the information, and evaluation of the source of the information. However, no research has examined…

Autonomy in Action: Linking the Act of Looking to Memory Formation in Infancy via Dynamic Neural Fields

ERIC Educational Resources Information Center

Perone, Sammy; Spencer, John P.

2013-01-01

Looking is a fundamental exploratory behavior by which infants acquire knowledge about the world. In theories of infant habituation, however, looking as an exploratory behavior has been deemphasized relative to the reliable nature with which looking indexes active cognitive processing. We present a new theory that connects looking to the dynamics…

Building phonetic categories: an argument for the role of sleep

PubMed Central

Earle, F. Sayako; Myers, Emily B.

2014-01-01

The current review provides specific predictions for the role of sleep-mediated memory consolidation in the formation of new speech sound representations. Specifically, this discussion will highlight selected literature on the different ideas concerning category representation in speech, followed by a broad overview of memory consolidation and how it relates to human behavior, as relevant to speech/perceptual learning. In combining behavioral and physiological accounts from animal models with insights from the human consolidation literature on auditory skill/word learning, we are in the early stages of understanding how the transfer of experiential information between brain structures during sleep manifests in changes to online perception. Arriving at the conclusion that this process is crucial in perceptual learning and the formation of novel categories, further speculation yields the adjacent claim that the habitual disruption in this process leads to impoverished quality in the representation of speech sounds. PMID:25477828

Central Executive Dysfunction and Deferred Prefrontal Processing in Veterans with Gulf War Illness.

PubMed

Hubbard, Nicholas A; Hutchison, Joanna L; Motes, Michael A; Shokri-Kojori, Ehsan; Bennett, Ilana J; Brigante, Ryan M; Haley, Robert W; Rypma, Bart

2014-05-01

Gulf War Illness is associated with toxic exposure to cholinergic disruptive chemicals. The cholinergic system has been shown to mediate the central executive of working memory (WM). The current work proposes that impairment of the cholinergic system in Gulf War Illness patients (GWIPs) leads to behavioral and neural deficits of the central executive of WM. A large sample of GWIPs and matched controls (MCs) underwent functional magnetic resonance imaging during a varied-load working memory task. Compared to MCs, GWIPs showed a greater decline in performance as WM-demand increased. Functional imaging suggested that GWIPs evinced separate processing strategies, deferring prefrontal cortex activity from encoding to retrieval for high demand conditions. Greater activity during high-demand encoding predicted greater WM performance. Behavioral data suggest that WM executive strategies are impaired in GWIPs. Functional data further support this hypothesis and suggest that GWIPs utilize less effective strategies during high-demand WM.

Central Executive Dysfunction and Deferred Prefrontal Processing in Veterans with Gulf War Illness

PubMed Central

Hubbard, Nicholas A.; Hutchison, Joanna L.; Motes, Michael A.; Shokri-Kojori, Ehsan; Bennett, Ilana J.; Brigante, Ryan M.; Haley, Robert W.; Rypma, Bart

2015-01-01

Gulf War Illness is associated with toxic exposure to cholinergic disruptive chemicals. The cholinergic system has been shown to mediate the central executive of working memory (WM). The current work proposes that impairment of the cholinergic system in Gulf War Illness patients (GWIPs) leads to behavioral and neural deficits of the central executive of WM. A large sample of GWIPs and matched controls (MCs) underwent functional magnetic resonance imaging during a varied-load working memory task. Compared to MCs, GWIPs showed a greater decline in performance as WM-demand increased. Functional imaging suggested that GWIPs evinced separate processing strategies, deferring prefrontal cortex activity from encoding to retrieval for high demand conditions. Greater activity during high-demand encoding predicted greater WM performance. Behavioral data suggest that WM executive strategies are impaired in GWIPs. Functional data further support this hypothesis and suggest that GWIPs utilize less effective strategies during high-demand WM. PMID:25767746

Analysis of the Negative-SET Behaviors in Cu/ZrO2/Pt Devices

NASA Astrophysics Data System (ADS)

Liu, Sen; Zhao, Xiaolong; Li, Qingjiang; Li, Nan; Wang, Wei; Liu, Qi; Xu, Hui

2016-12-01

Metal oxide-based electrochemical metallization memory (ECM) shows promising performance for next generation non-volatile memory. The negative-SET behavior has been observed in various oxide-based ECM devices. But the underlying mechanism of this behavior remains unaddressed and the role of the metal cation and oxygen vacancy in this behavior is unclear. In this work, we have observed two kinds of negative-SET (labeled as N-SET1 and N-SET2) behaviors in our Cu/ZrO2/Pt devices. Both the two behaviors can result in hard breakdown due to the high compliance current in reset process. The I-V characteristic shows that the two negative-SET behaviors have an obvious difference in operation voltage. Using four-probe resistance measurement method, the resistance-temperature characteristics of the ON-state after various negative-SET behaviors have been studied. The temperature dependence results demonstrate that the N-SET1 behavior is dominated by Cu conductive filament (CF) reformation caused by the Cu CF overgrowth phenomenon while the N-SET2 is related to the formation of oxygen vacancy CF. This work may provide a comprehensive understanding of the switching mechanism in oxide-based ECM devices.

Beyond arousal and valence: the importance of the biological versus social relevance of emotional stimuli.

PubMed

Sakaki, Michiko; Niki, Kazuhisa; Mather, Mara

2012-03-01

The present study addressed the hypothesis that emotional stimuli relevant to survival or reproduction (biologically emotional stimuli) automatically affect cognitive processing (e.g., attention, memory), while those relevant to social life (socially emotional stimuli) require elaborative processing to modulate attention and memory. Results of our behavioral studies showed that (1) biologically emotional images hold attention more strongly than do socially emotional images, (2) memory for biologically emotional images was enhanced even with limited cognitive resources, but (3) memory for socially emotional images was enhanced only when people had sufficient cognitive resources at encoding. Neither images' subjective arousal nor their valence modulated these patterns. A subsequent functional magnetic resonance imaging study revealed that biologically emotional images induced stronger activity in the visual cortex and greater functional connectivity between the amygdala and visual cortex than did socially emotional images. These results suggest that the interconnection between the amygdala and visual cortex supports enhanced attention allocation to biological stimuli. In contrast, socially emotional images evoked greater activity in the medial prefrontal cortex (MPFC) and yielded stronger functional connectivity between the amygdala and MPFC than did biological images. Thus, it appears that emotional processing of social stimuli involves elaborative processing requiring frontal lobe activity.

Beyond arousal and valence: The importance of the biological versus social relevance of emotional stimuli

PubMed Central

Sakaki, Michiko; Niki, Kazuhisa; Mather, Mara

2012-01-01

The present study addressed the hypothesis that emotional stimuli relevant to survival or reproduction (biologically emotional stimuli) automatically affect cognitive processing (e.g., attention; memory), while those relevant to social life (socially emotional stimuli) require elaborative processing to modulate attention and memory. Results of our behavioral studies showed that: a) biologically emotional images hold attention more strongly than socially emotional images, b) memory for biologically emotional images was enhanced even with limited cognitive resources, but c) memory for socially emotional images was enhanced only when people had sufficient cognitive resources at encoding. Neither images’ subjective arousal nor their valence modulated these patterns. A subsequent functional magnetic resonance imaging study revealed that biologically emotional images induced stronger activity in visual cortex and greater functional connectivity between amygdala and visual cortex than did socially emotional images. These results suggest that the interconnection between the amygdala and visual cortex supports enhanced attention allocation to biological stimuli. In contrast, socially emotional images evoked greater activity in medial prefrontal cortex (MPFC) and yielded stronger functional connectivity between amygdala and MPFC than biological images. Thus, it appears that emotional processing of social stimuli involves elaborative processing requiring frontal lobe activity. PMID:21964552

Optogenetic stimulation of a hippocampal engram activates fear memory recall

PubMed Central

Liu, Xu; Ramirez, Steve; Pang, Petti T.; Puryear, Corey B.; Govindarajan, Arvind; Deisseroth, Karl; Tonegawa, Susumu

2012-01-01

A specific memory is thought to be encoded by a sparse population of neurons1,2. These neurons can be tagged during learning for subsequent identification3 and manipulation4,5,6. Moreover, their ablation or inactivation results in reduced memory expression, suggesting their necessity in mnemonic processes. However, a critical question of sufficiency remains: can one elicit the behavioral output of a specific memory by directly activating a population of neurons that was active during learning? Here we show that optogenetic reactivation of hippocampal neurons activated during fear conditioning is sufficient to induce freezing behavior. We labeled a population of hippocampal dentate gyrus neurons activated during fear learning with channelrhodopsin-2 (ChR2)7,8 and later optically reactivated these neurons in a different context. The mice showed increased freezing only upon light stimulation, indicating light-induced fear memory recall. This freezing was not detected in non-fear conditioned mice expressing ChR2 in a similar proportion of cells, nor in fear conditioned mice with cells labeled by EYFP instead of ChR2. Finally, activation of cells labeled in a context not associated with fear did not evoke freezing in mice that were previously fear conditioned in a different context, suggesting that light-induced fear memory recall is context-specific. Together, our findings indicate that activating a sparse but specific ensemble of hippocampal neurons that contribute to a memory engram is sufficient for the recall of that memory. Moreover, our experimental approach offers a general method of mapping cellular populations bearing memory engrams. PMID:22441246

Composition-ratio influence on resistive switching behavior of solution-processed InGaZnO-based thin-film.

PubMed

Hwang, Yeong-Hyeon; Hwang, Inchan; Cho, Won-Ju

2014-11-01

The influence of composition ratio on the bipolar resistive switching behavior of resistive switching memory devices based on amorphous indium-gallium-zinc-oxide (a-IGZO) using the spin-coating process was investigated. To study the stoichiometric effects of the a-IGZO films on device characteristics, four devices with In/Ga/Zn stoichiometries of 1:1:1, 3:1:1, 1:3:1, and 1:1:3 were fabricated and characterized. The 3:1:1 film showed an ohmic behavior and the 1:1:3 film showed a rectifying switching behavior. The current-voltage characteristics of the a-IGZO films with stoichiometries of 1:1:1 and 1:3:1, however, showed a bipolar resistive memory switching behavior. We found that the three-fold increase in the gallium content ratio reduces the reset voltage from -0.9 to - 0.4 V and enhances the current ratio of high to low resistive states from 0.7 x 10(1) to 3 x 10(1). Our results show that the increase in the Ga composition ratio in the a-IGZO-based ReRAM cells effectively improves the device performance and reliability by increasing the initial defect density in the a-IGZO films.

The diagnostic utility of behavioral checklists in identifying children with ADHD and children with working memory deficits.

PubMed

Alloway, Tracy Packiam; Gathercole, Susan E; Holmes, Joni; Place, Maurice; Elliott, Julian G; Hilton, Kerry

2009-09-01

The present study investigated whether children with ADHD and those with working memory impairments have a common behavioral profile in the classroom. Three teacher checklists were used: the Conners' teacher rating scale (CTRS), the behavior rating inventory of executive function (BRIEF), and the working memory rating scale. The Conners' continuous performance test (CPT) was also included to determine whether there is a correspondence between performance on this widely used cognitive measure of attention deficits and teacher ratings of classroom behavior. All three behavior scales, but not the CPT, were able to successfully discriminate children with ADHD and those with working memory deficits from typically-developing children. Both the CTRS and the BRIEF discriminated a significant proportion of the children with ADHD from those with working memory deficits, indicating that while both groups exhibit behavioral problems in the classroom, they are characterized by differential attention profiles. The children with ADHD were identified on the basis of oppositional and hyperactive behavior, while those with working memory deficits were more inattentive.

Insights from Cognitive Neuroscience: The Importance of Executive Function for Early Reading Development and Education

ERIC Educational Resources Information Center

Cartwright, Kelly B.

2012-01-01

Research Findings: Executive function begins to develop in infancy and involves an array of processes, such as attention, inhibition, working memory, and cognitive flexibility, which provide the means by which individuals control their own behavior, work toward goals, and manage complex cognitive processes. Thus, executive function plays a…

Working Memory Profiles in HIV-Exposed, Uninfected and HIV-Infected Children: A Comparison with Neurotypical Controls

PubMed Central

Milligan, Robyn; Cockcroft, Kate

2017-01-01

This study compared the working memory profiles of three groups of children, namely HIV-infected (HIV-I; n = 95), HIV-exposed, uninfected (HIV-EU; n = 86) and an HIV-unexposed, uninfected, (HIV-UU; n = 92) neurotypical control group. Working memory, an executive function, plays an important role in frontal lobe-controlled behaviors, such as motivation, planning, decision making, and social interaction, and is a strong predictor of academic success in school children. Memory impairments have been identified in HIV-I children, particularly in visuospatial processing. Verbal working memory has not been commonly investigated in this population, while it is unknown how the working memory profiles of HIV-EU children compare to their HIV-I and HIV-UU peers. Of interest was whether the working memory profiles of the HIV-EU children would be more similar to the HIV-I group or to the uninfected control group. The results revealed no significant differences in working memory performance between the HIV-I and HIV-EU groups. However, this does not mean that the etiology of the working memory deficits is the same in the two groups, as these groups showed important differences when compared to the control group. In comparison to the controls, the HIV-I group experienced difficulties with processing tasks irrespective of whether they drew on a verbal or visuospatial modality. This appears to stem from a generalized executive function deficit that also interferes with working memory. In the HIV-EU group, difficulties occurred with verbally based tasks, irrespective of whether they required storage or processing. For this group, the dual demands of complex processing and using a second language seem to result in demand exceeding capacity on verbal tasks. Both groups experienced the greatest difficulties with verbal processing tasks for these different reasons. Thus, disruption of different cognitive abilities could result in similar working memory profiles, as evidenced in this study. This has implications for the underlying developmental neurobiology of HIV-I and HIV-EU children, as well the choice of appropriate measures to assist affected children. PMID:28729828

Visual Working Memory Enhances the Neural Response to Matching Visual Input.

PubMed

Gayet, Surya; Guggenmos, Matthias; Christophel, Thomas B; Haynes, John-Dylan; Paffen, Chris L E; Van der Stigchel, Stefan; Sterzer, Philipp

2017-07-12

Visual working memory (VWM) is used to maintain visual information available for subsequent goal-directed behavior. The content of VWM has been shown to affect the behavioral response to concurrent visual input, suggesting that visual representations originating from VWM and from sensory input draw upon a shared neural substrate (i.e., a sensory recruitment stance on VWM storage). Here, we hypothesized that visual information maintained in VWM would enhance the neural response to concurrent visual input that matches the content of VWM. To test this hypothesis, we measured fMRI BOLD responses to task-irrelevant stimuli acquired from 15 human participants (three males) performing a concurrent delayed match-to-sample task. In this task, observers were sequentially presented with two shape stimuli and a retro-cue indicating which of the two shapes should be memorized for subsequent recognition. During the retention interval, a task-irrelevant shape (the probe) was briefly presented in the peripheral visual field, which could either match or mismatch the shape category of the memorized stimulus. We show that this probe stimulus elicited a stronger BOLD response, and allowed for increased shape-classification performance, when it matched rather than mismatched the concurrently memorized content, despite identical visual stimulation. Our results demonstrate that VWM enhances the neural response to concurrent visual input in a content-specific way. This finding is consistent with the view that neural populations involved in sensory processing are recruited for VWM storage, and it provides a common explanation for a plethora of behavioral studies in which VWM-matching visual input elicits a stronger behavioral and perceptual response. SIGNIFICANCE STATEMENT Humans heavily rely on visual information to interact with their environment and frequently must memorize such information for later use. Visual working memory allows for maintaining such visual information in the mind's eye after termination of its retinal input. It is hypothesized that information maintained in visual working memory relies on the same neural populations that process visual input. Accordingly, the content of visual working memory is known to affect our conscious perception of concurrent visual input. Here, we demonstrate for the first time that visual input elicits an enhanced neural response when it matches the content of visual working memory, both in terms of signal strength and information content. Copyright © 2017 the authors 0270-6474/17/376638-10$15.00/0.

Mental Schemas Hamper Memory Storage of Goal-Irrelevant Information

PubMed Central

Sweegers, C. C. G.; Coleman, G. A.; van Poppel, E. A. M.; Cox, R.; Talamini, L. M.

2015-01-01

Mental schemas exert top-down control on information processing, for instance by facilitating the storage of schema-related information. However, given capacity-limits and competition in neural network processing, schemas may additionally exert their effects by suppressing information with low momentary relevance. In particular, when existing schemas suffice to guide goal-directed behavior, this may actually reduce encoding of the redundant sensory input, in favor of gaining efficiency in task performance. The present experiment set out to test this schema-induced shallow encoding hypothesis. Our approach involved a memory task in which faces had to be coupled to homes. For half of the faces the responses could be guided by a pre-learned schema, for the other half of the faces such a schema was not available. Memory storage was compared between schema-congruent and schema-incongruent items. To characterize putative schema effects, memory was assessed both with regard to visual details and contextual aspects of each item. The depth of encoding was also assessed through an objective neural measure: the parietal old/new ERP effect. This ERP effect, observed between 500–800 ms post-stimulus onset, is thought to reflect the extent of recollection: the retrieval of a vivid memory, including various contextual details from the learning episode. We found that schema-congruency induced substantial impairments in item memory and even larger ones in context memory. Furthermore, the parietal old/new ERP effect indicated higher recollection for the schema-incongruent than the schema-congruent memories. The combined findings indicate that, when goals can be achieved using existing schemas, this can hinder the in-depth processing of novel input, impairing the formation of perceptually detailed and contextually rich memory traces. Taking into account both current and previous findings, we suggest that schemas can both positively and negatively bias the processing of sensory input. An important determinant in this matter is likely related to momentary goals, such that mental schemas facilitate memory processing of goal-relevant input, but suppress processing of goal-irrelevant information. Highlights – Schema-congruent information suffers from shallow encoding. – Schema congruency induces poor item and context memory. – The parietal old/new effect is less pronounced for schema-congruent items. – Schemas exert different influences on memory formation depending on current goals. PMID:26635582

Influences of Appearance-Behavior Congruity on Memory and Social Judgments

PubMed Central

Cassidy, Brittany S.; Gutchess, Angela H.

2014-01-01

Prior work shows that appearance-behavior congruity impacts memory and evaluations. Building upon prior work, we assessed influences of appearance-behavior congruity on source memory and judgment strength to illustrate ways congruity effects permeate social cognition. We paired faces varying on trustworthiness with valenced behaviors to create congruent and incongruent face-behavior pairs. Young and older adults remembered congruent pairs better than incongruent, but both were remembered better than pairs with faces rated average in appearance. This suggests that multiple, even conflicting, valenced cues improve memory over receiving fewer cues. Consistent with our manipulation of facial trustworthiness, congruity effects were present in the strength of trustworthiness-related but not dominance judgments. Subtle age differences emerged in congruity effects when learning about others, with older adults showing effects for approach judgments given both high and low arousal behaviors. Young adults had congruity effects for approach, prosociality, and trustworthiness judgments, given high arousal behaviors only. These findings deepen our understanding of how appearance-behavior congruity impacts memory for and evaluations of others. PMID:25180615

Experience-Dependent Induction of Hippocampal ΔFosB Controls Learning.

PubMed

Eagle, Andrew L; Gajewski, Paula A; Yang, Miyoung; Kechner, Megan E; Al Masraf, Basma S; Kennedy, Pamela J; Wang, Hongbing; Mazei-Robison, Michelle S; Robison, Alfred J

2015-10-07

The hippocampus (HPC) is known to play an important role in learning, a process dependent on synaptic plasticity; however, the molecular mechanisms underlying this are poorly understood. ΔFosB is a transcription factor that is induced throughout the brain by chronic exposure to drugs, stress, and variety of other stimuli and regulates synaptic plasticity and behavior in other brain regions, including the nucleus accumbens. We show here that ΔFosB is also induced in HPC CA1 and DG subfields by spatial learning and novel environmental exposure. The goal of the current study was to examine the role of ΔFosB in hippocampal-dependent learning and memory and the structural plasticity of HPC synapses. Using viral-mediated gene transfer to silence ΔFosB transcriptional activity by expressing ΔJunD (a negative modulator of ΔFosB transcriptional function) or to overexpress ΔFosB, we demonstrate that HPC ΔFosB regulates learning and memory. Specifically, ΔJunD expression in HPC impaired learning and memory on a battery of hippocampal-dependent tasks in mice. Similarly, general ΔFosB overexpression also impaired learning. ΔJunD expression in HPC did not affect anxiety or natural reward, but ΔFosB overexpression induced anxiogenic behaviors, suggesting that ΔFosB may mediate attentional gating in addition to learning. Finally, we found that overexpression of ΔFosB increases immature dendritic spines on CA1 pyramidal cells, whereas ΔJunD reduced the number of immature and mature spine types, indicating that ΔFosB may exert its behavioral effects through modulation of HPC synaptic function. Together, these results suggest collectively that ΔFosB plays a significant role in HPC cellular morphology and HPC-dependent learning and memory. Consolidation of our explicit memories occurs within the hippocampus, and it is in this brain region that the molecular and cellular processes of learning have been most closely studied. We know that connections between hippocampal neurons are formed, eliminated, enhanced, and weakened during learning, and we know that some stages of this process involve alterations in the transcription of specific genes. However, the specific transcription factors involved in this process are not fully understood. Here, we demonstrate that the transcription factor ΔFosB is induced in the hippocampus by learning, regulates the shape of hippocampal synapses, and is required for memory formation, opening up a host of new possibilities for hippocampal transcriptional regulation. Copyright © 2015 the authors 0270-6474/15/3513773-11$15.00/0.

A Tradeoff Between Accuracy and Flexibility in a Working Memory Circuit Endowed with Slow Feedback Mechanisms.

PubMed

Pereira, Jacinto; Wang, Xiao-Jing

2015-10-01

Recent studies have shown that reverberation underlying mnemonic persistent activity must be slow, to ensure the stability of a working memory system and to give rise to long neural transients capable of accumulation of information over time. Is the slower the underlying process, the better? To address this question, we investigated 3 slow biophysical mechanisms that are activity-dependent and prominently present in the prefrontal cortex: Depolarization-induced suppression of inhibition (DSI), calcium-dependent nonspecific cationic current (ICAN), and short-term facilitation. Using a spiking network model for spatial working memory, we found that these processes enhance the memory accuracy by counteracting noise-induced drifts, heterogeneity-induced biases, and distractors. Furthermore, the incorporation of DSI and ICAN enlarges the range of network's parameter values required for working memory function. However, when a progressively slower process dominates the network, it becomes increasingly more difficult to erase a memory trace. We demonstrate this accuracy-flexibility tradeoff quantitatively and interpret it using a state-space analysis. Our results supports the scenario where N-methyl-d-aspartate receptor-dependent recurrent excitation is the workhorse for the maintenance of persistent activity, whereas slow synaptic or cellular processes contribute to the robustness of mnemonic function in a tradeoff that potentially can be adjusted according to behavioral demands. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

In search of consolidation of short-term memory in nonhuman animals.

PubMed

Calder, Amanda; White, K Geoffrey

2014-03-01

Wixted (Annual Review of Psychology, 55, 235 – 269, 2004) has argued that forgetting is due to consolidation failure. Previous research with humans and nonhuman animals has reported evidence for consolidation in intermediate or long-term memory (LTM). The present study examines whether consolidation occurs in short-term memory in pigeons. Delayed matching-to-sample accuracy was reduced when retroactive interference (an extraneous task in Experiment 1 or houselight illumination in Experiment 2) was interpolated in the retention interval. Accuracy was not greater, however, when interference occurred at the end of the retention interval, as compared with when it occurred at the beginning. That is, there was no evidence for consolidation in short-term memory for pigeons. We did find, however, the beginning–end effect originally reported by Roberts and Grant (Journal of Experimental Psychology: Animal Behavior Processes, 4, 219–236, 1978) and the recovery from forgetting reported by White and Brown (Journal of the Experimental Analysis of Behavior, 96, 177–189, 2011). The results are discussed in relation to temporal distinctiveness theory as an alternative to consolidation.

Memory effect versus exchange bias for maghemite nanoparticles

NASA Astrophysics Data System (ADS)

Nadeem, K.; Krenn, H.; Szabó, D. V.

2015-11-01

We studied the temperature dependence of memory and exchange bias effects and their dependence on each other in maghemite (γ-Fe2O3) nanoparticles by using magnetization studies. Memory effect in zero field cooled process in nanoparticles is a fingerprint of spin-glass behavior which can be due to i) surface disordered spins (surface spin-glass) and/or ii) randomly frozen and interacting nanoparticles core spins (super spin-glass). Temperature region (25-70 K) for measurements has been chosen just below the average blocking temperature (TB=75 K) of the nanoparticles. Memory effect (ME) shows a non-monotonous behavior with temperature. It shows a decreasing trend with decreasing temperature and nearly vanishes below 30 K. However it also decreased again near the blocking temperature of the nanoparticles e.g., 70 K. Exchange bias (EB) in these nanoparticles arises due to core/shell interface interactions. The EB increases sharply below 30 K due to increase in core/shell interactions, while ME starts vanishing below 30 K. We conclude that the core/shell interface interactions or EB have not enhanced the ME but may reduce it in these nanoparticles.

Facilitation of Memory for Extinction of Drug-Induced Conditioned Reward: Role of Amygdala and Acetylcholine

PubMed Central

Schroeder, Jason P.; Packard, Mark G.

2004-01-01

These experiments examined the effects of posttrial peripheral and intra-amygdala injections of the cholinergic muscarinic receptor agonist oxotremorine on memory consolidation underlying extinction of amphetamine conditioned place preference (CPP) behavior. Male Long-Evans rats were initially trained and tested for an amphetamine (2 mg/kg) CPP. Rats were subsequently given limited extinction training, followed by immediate posttrial peripheral or intrabasolateral amygdala injections of oxotremorine. A second CPP test was then administered, and the amount of time spent in the previously amphetamine-paired and saline-paired apparatus compartments was recorded. Peripheral (0.07 or 0.01 mg/kg) or intra-amygdala (10 ηg/0.5μL) postextinction trial injections of oxotremorine facilitated CPP extinction. Oxotremorine injections that were delayed 2 h posttrial training did not enhance CPP extinction, indicating a time-dependent effect of the drug on memory consolidation processes. The findings indicate that memory consolidation for extinction of approach behavior to environmental stimuli previously paired with drug reward can be facilitated by posttrial peripheral or intrabasolateral amygdala administration of a cholinergic agonist. PMID:15466320

Working Memory Load Strengthens Reward Prediction Errors.

PubMed

Collins, Anne G E; Ciullo, Brittany; Frank, Michael J; Badre, David

2017-04-19

Reinforcement learning (RL) in simple instrumental tasks is usually modeled as a monolithic process in which reward prediction errors (RPEs) are used to update expected values of choice options. This modeling ignores the different contributions of different memory and decision-making systems thought to contribute even to simple learning. In an fMRI experiment, we investigated how working memory (WM) and incremental RL processes interact to guide human learning. WM load was manipulated by varying the number of stimuli to be learned across blocks. Behavioral results and computational modeling confirmed that learning was best explained as a mixture of two mechanisms: a fast, capacity-limited, and delay-sensitive WM process together with slower RL. Model-based analysis of fMRI data showed that striatum and lateral prefrontal cortex were sensitive to RPE, as shown previously, but, critically, these signals were reduced when the learning problem was within capacity of WM. The degree of this neural interaction related to individual differences in the use of WM to guide behavioral learning. These results indicate that the two systems do not process information independently, but rather interact during learning. SIGNIFICANCE STATEMENT Reinforcement learning (RL) theory has been remarkably productive at improving our understanding of instrumental learning as well as dopaminergic and striatal network function across many mammalian species. However, this neural network is only one contributor to human learning and other mechanisms such as prefrontal cortex working memory also play a key role. Our results also show that these other players interact with the dopaminergic RL system, interfering with its key computation of reward prediction errors. Copyright © 2017 the authors 0270-6474/17/374332-11$15.00/0.

The positional-specificity effect reveals a passive-trace contribution to visual short-term memory.

PubMed

Postle, Bradley R; Awh, Edward; Serences, John T; Sutterer, David W; D'Esposito, Mark

2013-01-01

The positional-specificity effect refers to enhanced performance in visual short-term memory (VSTM) when the recognition probe is presented at the same location as had been the sample, even though location is irrelevant to the match/nonmatch decision. We investigated the mechanisms underlying this effect with behavioral and fMRI studies of object change-detection performance. To test whether the positional-specificity effect is a direct consequence of active storage in VSTM, we varied memory load, reasoning that it should be observed for all objects presented in a sub-span array of items. The results, however, indicated that although robust with a memory load of 1, the positional-specificity effect was restricted to the second of two sequentially presented sample stimuli in a load-of-2 experiment. An additional behavioral experiment showed that this disruption wasn't due to the increased load per se, because actively processing a second object--in the absence of a storage requirement--also eliminated the effect. These behavioral findings suggest that, during tests of object memory, position-related information is not actively stored in VSTM, but may be retained in a passive tag that marks the most recent site of selection. The fMRI data were consistent with this interpretation, failing to find location-specific bias in sustained delay-period activity, but revealing an enhanced response to recognition probes that matched the location of that trial's sample stimulus.

Segregating the core computational faculty of human language from working memory

PubMed Central

Makuuchi, Michiru; Bahlmann, Jörg; Anwander, Alfred; Friederici, Angela D.

2009-01-01

In contrast to simple structures in animal vocal behavior, hierarchical structures such as center-embedded sentences manifest the core computational faculty of human language. Previous artificial grammar learning studies found that the left pars opercularis (LPO) subserves the processing of hierarchical structures. However, it is not clear whether this area is activated by the structural complexity per se or by the increased memory load entailed in processing hierarchical structures. To dissociate the effect of structural complexity from the effect of memory cost, we conducted a functional magnetic resonance imaging study of German sentence processing with a 2-way factorial design tapping structural complexity (with/without hierarchical structure, i.e., center-embedding of clauses) and working memory load (long/short distance between syntactically dependent elements; i.e., subject nouns and their respective verbs). Functional imaging data revealed that the processes for structure and memory operate separately but co-operatively in the left inferior frontal gyrus; activities in the LPO increased as a function of structural complexity, whereas activities in the left inferior frontal sulcus (LIFS) were modulated by the distance over which the syntactic information had to be transferred. Diffusion tensor imaging showed that these 2 regions were interconnected through white matter fibers. Moreover, functional coupling between the 2 regions was found to increase during the processing of complex, hierarchically structured sentences. These results suggest a neuroanatomical segregation of syntax-related aspects represented in the LPO from memory-related aspects reflected in the LIFS, which are, however, highly interconnected functionally and anatomically. PMID:19416819

Multifractal analysis of information processing in hippocampal neural ensembles during working memory under Δ9-tetrahydrocannabinol administration

PubMed Central

Fetterhoff, Dustin; Opris, Ioan; Simpson, Sean L.; Deadwyler, Sam A.; Hampson, Robert E.; Kraft, Robert A.

2014-01-01

Background Multifractal analysis quantifies the time-scale-invariant properties in data by describing the structure of variability over time. By applying this analysis to hippocampal interspike interval sequences recorded during performance of a working memory task, a measure of long-range temporal correlations and multifractal dynamics can reveal single neuron correlates of information processing. New method Wavelet leaders-based multifractal analysis (WLMA) was applied to hippocampal interspike intervals recorded during a working memory task. WLMA can be used to identify neurons likely to exhibit information processing relevant to operation of brain–computer interfaces and nonlinear neuronal models. Results Neurons involved in memory processing (“Functional Cell Types” or FCTs) showed a greater degree of multifractal firing properties than neurons without task-relevant firing characteristics. In addition, previously unidentified FCTs were revealed because multifractal analysis suggested further functional classification. The cannabinoid-type 1 receptor partial agonist, tetrahydrocannabinol (THC), selectively reduced multifractal dynamics in FCT neurons compared to non-FCT neurons. Comparison with existing methods WLMA is an objective tool for quantifying the memory-correlated complexity represented by FCTs that reveals additional information compared to classification of FCTs using traditional z-scores to identify neuronal correlates of behavioral events. Conclusion z-Score-based FCT classification provides limited information about the dynamical range of neuronal activity characterized by WLMA. Increased complexity, as measured with multifractal analysis, may be a marker of functional involvement in memory processing. The level of multifractal attributes can be used to differentially emphasize neural signals to improve computational models and algorithms underlying brain–computer interfaces. PMID:25086297

New learning and unlearning: strangers or accomplices in threat memory attenuation?

PubMed Central

Clem, Roger L.; Schiller, Daniela

2016-01-01

To achieve greatest efficacy, therapies for attenuating fear and anxiety should preclude the re-emergence of emotional responses. Of relevance to this aim, preclinical models of threat memory reduction are considered to engage one of two discrete neural processes: either establishment of a new behavioral response that competes with, and thereby temporarily interferes with expression of, an intact threat memory (new learning), or one which modifies and thereby disrupts an intact threat memory (unlearning). We contend that a strict dichotomy of new learning and unlearning does not provide a compelling explanation for current data. Instead, we suggest the evidence warrants consideration of alternative models that assume cooperation rather than competition between formation of new cellular traces and the modification of preexisting ones. PMID:27079843

Activation of D1/5 Dopamine Receptors: A Common Mechanism for Enhancing Extinction of Fear and Reward-Seeking Behaviors.

PubMed

Abraham, Antony D; Neve, Kim A; Lattal, K Matthew

2016-07-01

Dopamine is critical for many processes that drive learning and memory, including motivation, prediction error, incentive salience, memory consolidation, and response output. Theories of dopamine's function in these processes have, for the most part, been developed from behavioral approaches that examine learning mechanisms in appetitive tasks. A parallel and growing literature indicates that dopamine signaling is involved in consolidation of memories into stable representations in aversive tasks such as fear conditioning. Relatively little is known about how dopamine may modulate memories that form during extinction, when organisms learn that the relation between previously associated events is severed. We investigated whether fear and reward extinction share common mechanisms that could be enhanced with dopamine D1/5 receptor activation. Pharmacological activation of dopamine D1/5 receptors (with SKF 81297) enhanced extinction of both cued and contextual fear. These effects also occurred in the extinction of cocaine-induced conditioned place preference, suggesting that the observed effects on extinction were not specific to a particular type of procedure (aversive or appetitive). A cAMP/PKA biased D1 agonist (SKF 83959) did not affect fear extinction, whereas a broadly efficacious D1 agonist (SKF 83822) promoted fear extinction. Together, these findings show that dopamine D1/5 receptor activation is a target for the enhancement of fear or reward extinction.

Working Memory Contributions to Reinforcement Learning Impairments in Schizophrenia

PubMed Central

Brown, Jaime K.; Gold, James M.; Waltz, James A.; Frank, Michael J.

2014-01-01

Previous research has shown that patients with schizophrenia are impaired in reinforcement learning tasks. However, behavioral learning curves in such tasks originate from the interaction of multiple neural processes, including the basal ganglia- and dopamine-dependent reinforcement learning (RL) system, but also prefrontal cortex-dependent cognitive strategies involving working memory (WM). Thus, it is unclear which specific system induces impairments in schizophrenia. We recently developed a task and computational model allowing us to separately assess the roles of RL (slow, cumulative learning) mechanisms versus WM (fast but capacity-limited) mechanisms in healthy adult human subjects. Here, we used this task to assess patients' specific sources of impairments in learning. In 15 separate blocks, subjects learned to pick one of three actions for stimuli. The number of stimuli to learn in each block varied from two to six, allowing us to separate influences of capacity-limited WM from the incremental RL system. As expected, both patients (n = 49) and healthy controls (n = 36) showed effects of set size and delay between stimulus repetitions, confirming the presence of working memory effects. Patients performed significantly worse than controls overall, but computational model fits and behavioral analyses indicate that these deficits could be entirely accounted for by changes in WM parameters (capacity and reliability), whereas RL processes were spared. These results suggest that the working memory system contributes strongly to learning impairments in schizophrenia. PMID:25297101

Face processing among twins with and without autism: social correlates and twin concordance.

PubMed

Neuhaus, Emily; Kresse, Anna; Faja, Susan; Bernier, Raphael A; Webb, Sara Jane

2016-01-01

Autism spectrum disorder (ASD) has a strong heritable basis, as evidenced by twin concordance rates. Within ASD, symptom domains may arise via independent genetic contributions, with varying heritabilities and genetic mechanisms. In this article, we explore social functioning in the form of (i) electrophysiological and behavioral measures of face processing (P1 and N170) and (ii) social behavior among child and adolescent twins with (N = 52) and without ASD (N = 66). Twins without ASD had better holistic face processing and face memory, faster P1 responses and greater sensitivity to the effects of facial inversion on P1. In contrast, N170 responses to faces were similar across diagnosis, with more negative amplitudes for faces vs non-face images. Across the sample, stronger social skills and fewer social difficulties were associated with faster P1 and N170 responses to upright faces, and better face memory. Twins were highly correlated within pairs across most measures, but correlations were significantly stronger for monozygotic vs dizygotic pairs on N170 latency and social problems. We suggest common developmental influences across twins for face processing and social behavior, but highlight (i) neural speed of face processing and (ii) social difficulties as important avenues in the search for genetic underpinnings in ASD. © The Author (2015). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

Effects of sleep on memory for conditioned fear and fear extinction

PubMed Central

Pace-Schott, Edward F.; Germain, Anne; Milad, Mohammed R.

2015-01-01

Learning and memory for extinction of conditioned fear is a basic mammalian mechanism for regulating negative emotion. Sleep promotes both the consolidation of memory and the regulation of emotion. Sleep can influence consolidation and modification of memories associated with both fear and its extinction. After brief overviews of the behavior and neural circuitry associated with fear conditioning, extinction learning and extinction memory in the rodent and human, interactions of sleep with these processes will be examined. Animal and human studies suggest that sleep can serve to consolidate both fear and extinction memory. In humans, sleep also promotes generalization of extinction memory. Time-of-day effects on extinction learning and generalization are also seen. REM may be a sleep stage of particular importance for the consolidation of both fear and extinction memory as evidenced by selective REM deprivation experiments. REM sleep is accompanied by selective activation of the same limbic structures implicated in the learning and memory of fear and extinction. Preliminary evidence also suggests extinction learning can take place during slow wave sleep. Study of low-level processes such as conditioning, extinction and habituation may allow sleep effects on emotional memory to be identified and inform study of sleep’s effects on more complex, emotionally salient declarative memories. Anxiety disorders are marked by impairments of both sleep and extinction memory. Improving sleep quality may ameliorate anxiety disorders by strengthening naturally acquired extinction. Strategically timed sleep may be used to enhance treatment of anxiety by strengthening therapeutic extinction learned via exposure therapy. PMID:25894546

Effects of sleep on memory for conditioned fear and fear extinction.

PubMed

Pace-Schott, Edward F; Germain, Anne; Milad, Mohammed R

2015-07-01

Learning and memory for extinction of conditioned fear is a basic mammalian mechanism for regulating negative emotion. Sleep promotes both the consolidation of memory and the regulation of emotion. Sleep can influence consolidation and modification of memories associated with both fear and its extinction. After brief overviews of the behavior and neural circuitry associated with fear conditioning, extinction learning, and extinction memory in the rodent and human, interactions of sleep with these processes will be examined. Animal and human studies suggest that sleep can serve to consolidate both fear and extinction memory. In humans, sleep also promotes generalization of extinction memory. Time-of-day effects on extinction learning and generalization are also seen. Rapid eye movement (REM) may be a sleep stage of particular importance for the consolidation of both fear and extinction memory as evidenced by selective REM deprivation experiments. REM sleep is accompanied by selective activation of the same limbic structures implicated in the learning and memory of fear and extinction. Preliminary evidence also suggests extinction learning can take place during slow wave sleep. Study of low-level processes such as conditioning, extinction, and habituation may allow sleep effects on emotional memory to be identified and inform study of sleep's effects on more complex, emotionally salient declarative memories. Anxiety disorders are marked by impairments of both sleep and extinction memory. Improving sleep quality may ameliorate anxiety disorders by strengthening naturally acquired extinction. Strategically timed sleep may be used to enhance treatment of anxiety by strengthening therapeutic extinction learned via exposure therapy. (PsycINFO Database Record (c) 2015 APA, all rights reserved).

Declarative and Non-declarative Memory Consolidation in Children with Sleep Disorder.

PubMed

Csábi, Eszter; Benedek, Pálma; Janacsek, Karolina; Zavecz, Zsófia; Katona, Gábor; Nemeth, Dezso

2015-01-01

Healthy sleep is essential in children's cognitive, behavioral, and emotional development. However, remarkably little is known about the influence of sleep disorders on different memory processes in childhood. Such data could give us a deeper insight into the effect of sleep on the developing brain and memory functions and how the relationship between sleep and memory changes from childhood to adulthood. In the present study we examined the effect of sleep disorder on declarative and non-declarative memory consolidation by testing children with sleep-disordered breathing (SDB) which is characterized by disrupted sleep structure. We used a story recall task to measure declarative memory and Alternating Serial Reaction time (ASRT) task to assess non-declarative memory. This task enables us to measure two aspects of non-declarative memory, namely general motor skill learning and sequence-specific learning. There were two sessions: a learning phase and a testing phase, separated by a 12 h offline period with sleep. Our data showed that children with SDB exhibited a generally lower declarative memory performance both in the learning and testing phase; however, both the SDB and control groups exhibited retention of the previously recalled items after the offline period. Here we showed intact non-declarative consolidation in SDB group in both sequence-specific and general motor skill. These findings suggest that sleep disorders in childhood have a differential effect on different memory processes (online vs. offline) and give us insight into how sleep disturbances affects developing brain.

Declarative and Non-declarative Memory Consolidation in Children with Sleep Disorder

PubMed Central

Csábi, Eszter; Benedek, Pálma; Janacsek, Karolina; Zavecz, Zsófia; Katona, Gábor; Nemeth, Dezso

2016-01-01

Healthy sleep is essential in children’s cognitive, behavioral, and emotional development. However, remarkably little is known about the influence of sleep disorders on different memory processes in childhood. Such data could give us a deeper insight into the effect of sleep on the developing brain and memory functions and how the relationship between sleep and memory changes from childhood to adulthood. In the present study we examined the effect of sleep disorder on declarative and non-declarative memory consolidation by testing children with sleep-disordered breathing (SDB) which is characterized by disrupted sleep structure. We used a story recall task to measure declarative memory and Alternating Serial Reaction time (ASRT) task to assess non-declarative memory. This task enables us to measure two aspects of non-declarative memory, namely general motor skill learning and sequence-specific learning. There were two sessions: a learning phase and a testing phase, separated by a 12 h offline period with sleep. Our data showed that children with SDB exhibited a generally lower declarative memory performance both in the learning and testing phase; however, both the SDB and control groups exhibited retention of the previously recalled items after the offline period. Here we showed intact non-declarative consolidation in SDB group in both sequence-specific and general motor skill. These findings suggest that sleep disorders in childhood have a differential effect on different memory processes (online vs. offline) and give us insight into how sleep disturbances affects developing brain. PMID:26793090

Traces of Drosophila Memory

PubMed Central

Davis, Ronald L.

2012-01-01

Summary Studies using functional cellullar imaging of living flies have identified six memory traces that form in the olfactory nervous system after conditioning with odors. These traces occur in distinct nodes of the olfactory nervous system, form and disappear across different windows of time, and are detected in the imaged neurons as increased calcium influx or synaptic release in response to the conditioned odor. Three traces form at, or near acquisition and co-exist with short-term behavioral memory. One trace forms with a delay after learning and co-exists with intermediate-term behavioral memory. Two traces form many hours after acquisition and co-exist with long-term behavioral memory. The transient memory traces may support behavior across the time-windows of their existence. The experimental approaches for dissecting memory formation in the fly, ranging from the molecular to the systems, make it an ideal system for dissecting the logic by which the nervous system organizes and stores different temporal forms of memory. PMID:21482352

Loss of Maged1 results in obesity, deficits of social interactions, impaired sexual behavior and severe alteration of mature oxytocin production in the hypothalamus.

PubMed

Dombret, Carlos; Nguyen, Tuan; Schakman, Olivier; Michaud, Jacques L; Hardin-Pouzet, Hélène; Bertrand, Mathieu J M; De Backer, Olivier

2012-11-01

MAGED1, NECDIN and MAGEL2 are members of the MAGE gene family. The latter two of these genes have been involved in Prader-Willi syndrome (PWS), which includes hyperphagia, repetitive and compulsive behaviors, and cognitive impairment. Here, we show that Maged1-deficient mice develop progressive obesity associated with hyperphagia and reduced motor activity. Loss of Maged1 also results in a complex behavioral syndrome that includes reduced social interactions and memory, deficient sexual behavior, as well as increased anxiety and self-grooming. Oxytocin (OT), which is produced in the hypothalamus, can act as a neurotransmitter that reduces anxiety, promotes social behaviors and regulates food intake. Growing evidences indicate that OT is involved in autism. We found that Maged1 mutants showed a severe reduction in the levels of mature OT, but not of its precursors, in the hypothalamus. Moreover, the administration of OT rescued the deficit in social memory of these mice. We conclude that Maged1 is required for OT processing or stability. A decrease in mature OT levels in Maged1 mutants affects social interactions and possibly other behavioral processes. Our observations suggest that, in human, MAGED1 could play a role in autism or cause a neurodevelopmental condition that is reminiscent of the PWS.

Effects of working memory load on visual selective attention: behavioral and electrophysiological evidence.

PubMed

Pratt, Nikki; Willoughby, Adrian; Swick, Diane

2011-01-01

Working memory and attention interact in a way that enables us to focus on relevant items and maintain current goals. The influence of working memory on attention has been noted in several studies using dual task designs. Multitasking increases the demands on working memory and reduces the amount of resources available for cognitive control functions such as resolving stimulus conflict. However, few studies have investigated the temporal activation of the cortex while multitasking. The present study addresses the extent to which working memory load influences early (P1) and late (P300) attention-sensitive event-related potential components using a dual task paradigm. Participants performed an arrow flanker task alone (single task condition) or concurrently with a Sternberg memory task (dual task condition). In the flanker task, participants responded to the direction of a central arrow surrounded by congruent or incongruent arrows. In the dual task condition, participants were presented with a Sternberg task that consisted of either four or seven consonants to remember prior to a short block of flanker trials. Participants were slower and less accurate on incongruent versus congruent trials. Furthermore, accuracy on incongruent trials was reduced in both dual task conditions. Likewise, P300 amplitude to incongruent flanker stimuli decreased when working memory load increased. These findings suggest that interference from incongruent flankers was more difficult to suppress when working memory was taxed. In addition, P1 amplitude was diminished on all flanker trials in the dual task condition. This result indicates that top-down attentional control over early visual processing is diminished by increasing demands on working memory. Both the behavioral and electrophysiological results suggest that working memory is critical in maintaining attentional focus and resolving conflict.

Effects of Working Memory Load on Visual Selective Attention: Behavioral and Electrophysiological Evidence

PubMed Central

Pratt, Nikki; Willoughby, Adrian; Swick, Diane

2011-01-01

Working memory and attention interact in a way that enables us to focus on relevant items and maintain current goals. The influence of working memory on attention has been noted in several studies using dual task designs. Multitasking increases the demands on working memory and reduces the amount of resources available for cognitive control functions such as resolving stimulus conflict. However, few studies have investigated the temporal activation of the cortex while multitasking. The present study addresses the extent to which working memory load influences early (P1) and late (P300) attention-sensitive event-related potential components using a dual task paradigm. Participants performed an arrow flanker task alone (single task condition) or concurrently with a Sternberg memory task (dual task condition). In the flanker task, participants responded to the direction of a central arrow surrounded by congruent or incongruent arrows. In the dual task condition, participants were presented with a Sternberg task that consisted of either four or seven consonants to remember prior to a short block of flanker trials. Participants were slower and less accurate on incongruent versus congruent trials. Furthermore, accuracy on incongruent trials was reduced in both dual task conditions. Likewise, P300 amplitude to incongruent flanker stimuli decreased when working memory load increased. These findings suggest that interference from incongruent flankers was more difficult to suppress when working memory was taxed. In addition, P1 amplitude was diminished on all flanker trials in the dual task condition. This result indicates that top-down attentional control over early visual processing is diminished by increasing demands on working memory. Both the behavioral and electrophysiological results suggest that working memory is critical in maintaining attentional focus and resolving conflict. PMID:21716633

The remains of the day in dissociative amnesia.

PubMed

Staniloiu, Angelica; Markowitsch, Hans J

2012-04-10

Memory is not a unity, but is divided along a content axis and a time axis, respectively. Along the content dimension, five long-term memory systems are described, according to their hierarchical ontogenetic and phylogenetic organization. These memory systems are assumed to be accompanied by different levels of consciousness. While encoding is based on a hierarchical arrangement of memory systems from procedural to episodic-autobiographical memory, retrieval allows independence in the sense that no matter how information is encoded, it can be retrieved in any memory system. Thus, we illustrate the relations between various long-term memory systems by reviewing the spectrum of abnormalities in mnemonic processing that may arise in the dissociative amnesia-a condition that is usually characterized by a retrieval blockade of episodic-autobiographical memories and occurs in the context of psychological trauma, without evidence of brain damage on conventional structural imaging. Furthermore, we comment on the functions of implicit memories in guiding and even adaptively molding the behavior of patients with dissociative amnesia and preserving, in the absence of autonoetic consciousness, the so-called "internal coherence of life".

The Remains of the Day in Dissociative Amnesia

PubMed Central

Staniloiu, Angelica; Markowitsch, Hans J.

2012-01-01

Memory is not a unity, but is divided along a content axis and a time axis, respectively. Along the content dimension, five long-term memory systems are described, according to their hierarchical ontogenetic and phylogenetic organization. These memory systems are assumed to be accompanied by different levels of consciousness. While encoding is based on a hierarchical arrangement of memory systems from procedural to episodic-autobiographical memory, retrieval allows independence in the sense that no matter how information is encoded, it can be retrieved in any memory system. Thus, we illustrate the relations between various long-term memory systems by reviewing the spectrum of abnormalities in mnemonic processing that may arise in the dissociative amnesia—a condition that is usually characterized by a retrieval blockade of episodic-autobiographical memories and occurs in the context of psychological trauma, without evidence of brain damage on conventional structural imaging. Furthermore, we comment on the functions of implicit memories in guiding and even adaptively molding the behavior of patients with dissociative amnesia and preserving, in the absence of autonoetic consciousness, the so-called “internal coherence of life”. PMID:24962768

β1-Adrenoceptor in the Central Amygdala Is Required for Unconditioned Stimulus-Induced Drug Memory Reconsolidation

PubMed Central

Zhu, Huiwen; Zhou, Yiming; Liu, Zhiyuan; Chen, Xi; Li, Yanqing; Liu, Xing; Ma, Lan

2018-01-01

Abstract Background Drug memories become labile and reconsolidated after retrieval by presentation of environmental cues (conditioned stimulus) or drugs (unconditioned stimulus). Whether conditioned stimulus and unconditioned stimulus retrieval trigger different memory reconsolidation processes is not clear. Methods Protein synthesis inhibitor or β-adrenergic receptor (β-AR) antagonist was systemically administrated or intra-central amygdala infused immediately after cocaine reexposure in cocaine-conditioned place preference or self-administration mice models. β-ARs were selectively knocked out in the central amygdala to further confirm the role of β-adrenergic receptor in cocaine reexposure-induced memory reconsolidation of cocaine-conditioned place preference. Results Cocaine reexposure triggered de novo protein synthesis dependent memory reconsolidation of cocaine-conditioned place preference. Cocaine-priming-induced reinstatement was also impaired with post cocaine retrieval manipulation, in contrast to the relapse behavior with post context retrieval manipulation. Cocaine retrieval, but not context retrieval, induced central amygdala activation. Protein synthesis inhibitor or β1-adrenergic receptor antagonist infused in the central amygdala after cocaine retrieval, but not context retrieval, inhibited memory reconsolidation and reinstatement. β1-adrenergic receptor knockout in the central amygdala suppressed cocaine retrieval-triggered memory reconsolidation and reinstatement of cocaine conditioned place preference. β1-adrenergic receptor antagonism after cocaine retrieval also impaired reconsolidation and reinstatement of cocaine self-administration. Conclusions Cocaine reward memory triggered by unconditioned stimulus retrieval is distinct from conditioned stimulus retrieval. Unconditioned stimulus retrieval induced reconsolidation of cocaine reward memory depends on β1-adrenergic signaling in the central amygdala. Post unconditioned stimulus retrieval manipulation can prevent drug memory reconsolidation and relapse to cocaine, thus providing a potential strategy for the prevention of substance addiction. Significance Statement It is well known that drug memories become labile and reconsolidated upon retrieval by the presentation of conditioned stimulus (CS) or unconditioned stimulus (US). Whether CS and US retrieval trigger different memory reconsolidation processes is unknown. In this study, we found that US retrieval, but not CS retrieval, triggered memory reconsolidation of cocaine-conditioned place preference dependent on β1-AR and de novo protein synthesis in the central amygdala. Furthermore, cocaine priming-induced reinstatement was impaired with post US retrieval manipulation in contrast to the relapse behavior with post CS retrieval manipulation. In cocaine self-administration, β1-AR antagonism after US retrieval also impaired reconsolidation and reinstatement. Our study indicates that reconsolidation of cocaine reward memory triggered by US retrieval is distinct from CS retrieval. US retrieval induced reconsolidation of cocaine reward memory depends on β1-adrenergic signaling in the central amygdala. PMID:29216351

Analysis of memory use for improved design and compile-time allocation of local memory

NASA Technical Reports Server (NTRS)

Mcniven, Geoffrey D.; Davidson, Edward S.

1986-01-01

Trace analysis techniques are used to study memory referencing behavior for the purpose of designing local memories and determining how to allocate them for data and instructions. In an attempt to assess the inherent behavior of the source code, the trace analysis system described here reduced the effects of the compiler and host architecture on the trace by using a technical called flattening. The variables in the trace, their associated single-assignment values, and references are histogrammed on the basis of various parameters describing memory referencing behavior. Bounds are developed specifying the amount of memory space required to store all live values in a particular histogram class. The reduction achieved in main memory traffic by allocating local memory is specified for each class.

Impaired long-term memory retention: common denominator for acutely or genetically reduced hippocampal neurogenesis in adult mice.

PubMed

Ben Abdallah, Nada M-B; Filipkowski, Robert K; Pruschy, Martin; Jaholkowski, Piotr; Winkler, Juergen; Kaczmarek, Leszek; Lipp, Hans-Peter

2013-09-01

In adult rodents, decreasing hippocampal neurogenesis experimentally using different approaches often impairs performance in hippocampus-dependent processes. Nonetheless, functional relevance of adult neurogenesis is far from being unraveled, and deficits so far described in animal models often lack reproducibility. One hypothesis is that such differences might be the consequence of the extent of the methodological specificity used to alter neurogenesis rather than the extent to which adult neurogenesis is altered. To address this, we focused on cranial irradiation, the most widely used technique to impair hippocampal neurogenesis and consequentially induce hippocampus-dependent behavioral deficits. To investigate the specificity of the technique, we thus exposed 4-5 months old female cyclin D2 knockout mice, a model lacking physiological levels of olfactory and hippocampal neurogenesis, to an X-ray dose of 10 Gy, reported to specifically affect transiently amplifying precursors. After a recovery period of 1.5 months, behavioral tests were performed and probed for locomotor activity, habituation, anxiety, and spatial learning and memory. Spatial learning in the Morris water maze was intact in all experimental groups. Although spatial memory retention assessed 24h following acquisition was also intact in all mice, irradiated wild type and cyclin D2 knockout mice displayed memory deficits one week after acquisition. In addition, we observed significant differences in tests addressing anxiety and locomotor activity dependent on the technique used to alter neurogenesis. Whereas irradiated mice were hyperactive regardless of their genotype, cyclin D2 knockout mice were hypoactive in most of the tests and displayed altered habituation. The present study emphasizes that different approaches aimed at decreasing adult hippocampal neurogenesis may result in distinct behavioral impairments related to locomotion and anxiety. In contrast, spatial long-term memory retention is consistently altered after both approaches suggesting a plausible implication of hippocampal neurogenesis in this cognitive process. Copyright © 2013 Elsevier B.V. All rights reserved.

Epigenetic regulation of estrogen-dependent memory

PubMed Central

Fortress, Ashley M.; Frick, Karyn M.

2014-01-01

Hippocampal memory formation is highly regulated by post-translational histone modifications and DNA methylation. Accordingly, these epigenetic processes play a major role in the effects of modulatory factors, such as sex steroid hormones, on hippocampal memory. Our laboratory recently demonstrated that the ability of the potent estrogen 17β-estradiol (E2) to enhance hippocampal-dependent novel object recognition memory in ovariectomized female mice requires ERK-dependent histone H3 acetylation and DNA methylation in the dorsal hippocampus. Although these data provide valuable insight into the chromatin modifications that mediate the memory-enhancing effects of E2, epigenetic regulation of gene expression is enormously complex. Therefore, more research is needed to fully understand how E2 and other hormones employ epigenetic alterations to shape behavior. This review discusses the epigenetic alterations shown thus far to regulate hippocampal memory, briefly reviews the effects of E2 on hippocampal function, and describes in detail our work on epigenetic regulation of estrogenic memory enhancement. PMID:24878494

Greater loss of object than spatial mnemonic discrimination in aged adults.

PubMed

Reagh, Zachariah M; Ho, Huy D; Leal, Stephanie L; Noche, Jessica A; Chun, Amanda; Murray, Elizabeth A; Yassa, Michael A

2016-04-01

Previous studies across species have established that the aging process adversely affects certain memory-related brain regions earlier than others. Behavioral tasks targeted at the function of vulnerable regions can provide noninvasive methods for assessing the integrity of particular components of memory throughout the lifespan. The present study modified a previous task designed to separately but concurrently test detailed memory for object identity and spatial location. Memory for objects or items is thought to rely on perirhinal and lateral entorhinal cortices, among the first targets of Alzheimer's related neurodegeneration. In line with prior work, we split an aged adult sample into "impaired" and "unimpaired" groups on the basis of a standardized word-learning task. The "impaired" group showed widespread difficulty with memory discrimination, whereas the "unimpaired" group showed difficulty with object, but not spatial memory discrimination. These findings support the hypothesized greater age-related impacts on memory for objects or items in older adults, perhaps even with healthy aging. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

Synchrony and desynchrony in circadian clocks: impacts on learning and memory

PubMed Central

Krishnan, Harini C.

2015-01-01

Circadian clocks evolved under conditions of environmental variation, primarily alternating light dark cycles, to enable organisms to anticipate daily environmental events and coordinate metabolic, physiological, and behavioral activities. However, modern lifestyle and advances in technology have increased the percentage of individuals working in phases misaligned with natural circadian activity rhythms. Endogenous circadian oscillators modulate alertness, the acquisition of learning, memory formation, and the recall of memory with examples of circadian modulation of memory observed across phyla from invertebrates to humans. Cognitive performance and memory are significantly diminished when occurring out of phase with natural circadian rhythms. Disruptions in circadian regulation can lead to impairment in the formation of memories and manifestation of other cognitive deficits. This review explores the types of interactions through which the circadian clock modulates cognition, highlights recent progress in identifying mechanistic interactions between the circadian system and the processes involved in memory formation, and outlines methods used to remediate circadian perturbations and reinforce circadian adaptation. PMID:26286653

Mechanisms of Memory Enhancement

PubMed Central

Stern, Sarah A.

2012-01-01

The ongoing quest for memory enhancement is one that grows necessary as the global population increasingly ages. The extraordinary progress that has been made in the past few decades elucidating the underlying mechanisms of how long-term memories are formed has provided insight into how memories might also be enhanced. Capitalizing on this knowledge, it has been postulated that targeting many of the same mechanisms, including CREB activation, AMPA/NMDA receptor trafficking, neuromodulation (e.g. via dopamine, adrenaline, cortisol or acetylcholine) and metabolic processes (e.g. via glucose and insulin) may all lead to the enhancement of memory. These and other mechanisms and/or approaches have been tested via genetic or pharmacological methods in animal models, and several have been investigated in humans as well. In addition, a number of behavioral methods, including exercise and reconsolidation, may also serve to strengthen and enhance memories. By capitalizing on this knowledge and continuing to investigate these promising avenues, memory enhancement may indeed be achieved in the future. PMID:23151999

Epigenetic regulation of estrogen-dependent memory.

PubMed

Fortress, Ashley M; Frick, Karyn M

2014-10-01

Hippocampal memory formation is highly regulated by post-translational histone modifications and DNA methylation. Accordingly, these epigenetic processes play a major role in the effects of modulatory factors, such as sex steroid hormones, on hippocampal memory. Our laboratory recently demonstrated that the ability of the potent estrogen 17β-estradiol (E2) to enhance hippocampal-dependent novel object recognition memory in ovariectomized female mice requires ERK-dependent histone H3 acetylation and DNA methylation in the dorsal hippocampus. Although these data provide valuable insight into the chromatin modifications that mediate the memory-enhancing effects of E2, epigenetic regulation of gene expression is enormously complex. Therefore, more research is needed to fully understand how E2 and other hormones employ epigenetic alterations to shape behavior. This review discusses the epigenetic alterations shown thus far to regulate hippocampal memory, briefly reviews the effects of E2 on hippocampal function, and describes in detail our work on epigenetic regulation of estrogenic memory enhancement. Copyright © 2014 Elsevier Inc. All rights reserved.

Sleeping on the motor engram: The multifaceted nature of sleep-related motor memory consolidation.

PubMed

King, Bradley R; Hoedlmoser, Kerstin; Hirschauer, Franziska; Dolfen, Nina; Albouy, Genevieve

2017-09-01

For the past two decades, it has generally been accepted that sleep benefits motor memory consolidation processes. This notion, however, has been challenged by recent studies and thus the sleep and motor memory story is equivocal. Currently, and in contrast to the declarative memory domain, a comprehensive overview and synthesis of the effects of post-learning sleep on the behavioral and neural correlates of motor memory consolidation is not available. We therefore provide an extensive review of the literature in order to highlight that sleep-dependent motor memory consolidation depends upon multiple boundary conditions, including particular features of the motor task, the recruitment of relevant neural substrates (and the hippocampus in particular), as well as the specific architecture of the intervening sleep period (specifically, sleep spindle and slow wave activity). For our field to continue to advance, future research must consider the multifaceted nature of sleep-related motor memory consolidation. Copyright © 2017 Elsevier Ltd. All rights reserved.

A process dissociation approach to objective-projective test score interrelationships.

PubMed

Bornstein, Robert F

2002-02-01

Even when self-report and projective measures of a given trait or motive both predict theoretically related features of behavior, scores on the 2 tests correlate modestly with each other. This article describes a process dissociation framework for personality assessment, derived from research on implicit memory and learning, which can resolve these ostensibly conflicting results. Research on interpersonal dependency is used to illustrate 3 key steps in the process dissociation approach: (a) converging behavioral predictions, (b) modest test score intercorrelations, and (c) delineation of variables that differentially affect self-report and projective test scores. Implications of the process dissociation framework for personality assessment and test development are discussed.

On cognitive ecology and the environmental factors that promote Alzheimer disease: lessons from Octodon degus (Rodentia: Octodontidae).

PubMed

Rivera, Daniela S; Inestrosa, Nibaldo C; Bozinovic, Francisco

2016-02-20

Cognitive ecologist posits that the more efficiently an animal uses information from the biotic and abiotic environment, the more adaptive are its cognitive abilities. Nevertheless, this approach does not test for natural neurodegenerative processes under field or experimental conditions, which may recover animals information processing and decision making and may explain, mechanistically, maladaptive behaviors. Here, we call for integrative approaches to explain the relationship between ultimate and proximate mechanisms behind social behavior. We highlight the importance of using the endemic caviomorph rodent Octodon degus as a valuable natural model for mechanistic studies of social behavior and to explain how physical environments can shape social experiences that might influence impaired cognitive abilities and the onset and progression of neurodegenerative disorders such as Alzheimer disease. We consequently suggest neuroecological approaches to examine how key elements of the environment may affect neural and cognitive mechanisms associated with learning, memory processes and brain structures involved in social behavior. We propose the following three core objectives of a program comprising interdisciplinary research in O. degus, namely: (1) to determine whether diet types provided after weaning can lead to cognitive impairment associated with spatial memory, learning and predisposing to develop Alzheimer disease in younger ages; (2) to examine if early life social experience has long term effects on behavior and cognitive responses and risk for development Alzheimer disease in later life and (3) To determine if an increase of social interactions in adult degu reared in different degree of social stressful conditions alter their behavior and cognitive responses.

The Incidental Influence of Memories of Past Eating Occasions on Consumers' Emotional Responses to Food and Food-Related Behaviors.

PubMed

Piqueras-Fiszman, Betina; Jaeger, Sara R

2016-01-01

Our memories of past eating experiences are influential in shaping food preferences and consumption behavior, and the emotions that people associate to these memories are linked to their attitudes toward foods and their everyday food-related behaviors. This work studies the impact that food-related memories have on peoples' emotional state and how this state is projected in a subsequent evaluation of images pertaining to food and food-related behaviors. Focus is placed on guilt and shame emotions. Through an online survey, three memories were investigated (a positive meal, a routine evening meal, and an overeating occasion) among UK consumers (N = 710). Participants primed with the overeating memory evaluated images related to junk food as conveying more feelings of guilt and shame than did participants primed with the memory of a positive meal. Moreover, this effect was moderated by participants' dietary restraint status. Participants classified as having a high dietary restraint had stronger associations with the emotions guilt and shame than participants classified as low in dietary restraint. In contrast, a memory of a positive meal did not lead to positive valuations of any of the food-related images shown. Overall, the findings from the present study illustrate the partial impact that personal food memories have on consumers' emotional response toward food-related issues, which in turn has the potential to affect future behavior. This study therefore contributes to the literature about cognitive effects on food attitudes and behavior. Furthermore, the results suggest that the empirical approach may be tapping into possibly unconscious emotions toward foods and food-related behavior.