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Sample records for memory modules techniques

  1. MEMORY MODULATION

    Roozendaal, Benno; McGaugh, James L.

    2011-01-01

    Our memories are not all created equally strong: Some experiences are well remembered while others are remembered poorly, if at all. Research on memory modulation investigates the neurobiological processes and systems that contribute to such differences in the strength of our memories. Extensive evidence from both animal and human research indicates that emotionally significant experiences activate hormonal and brain systems that regulate the consolidation of newly acquired memories. These effects are integrated through noradrenergic activation of the basolateral amygdala which regulates memory consolidation via interactions with many other brain regions involved in consolidating memories of recent experiences. Modulatory systems not only influence neurobiological processes underlying the consolidation of new information, but also affect other mnemonic processes, including memory extinction, memory recall and working memory. In contrast to their enhancing effects on consolidation, adrenal stress hormones impair memory retrieval and working memory. Such effects, as with memory consolidation, require noradrenergic activation of the basolateral amygdala and interactions with other brain regions. PMID:22122145

  2. Memory Modulation

    Roozendaal, Benno; McGaugh, James L.

    2011-01-01

    Our memories are not all created equally strong: Some experiences are well remembered while others are remembered poorly, if at all. Research on memory modulation investigates the neurobiological processes and systems that contribute to such differences in the strength of our memories. Extensive

  3. Bidirectional Modulation of Recognition Memory.

    Ho, Jonathan W; Poeta, Devon L; Jacobson, Tara K; Zolnik, Timothy A; Neske, Garrett T; Connors, Barry W; Burwell, Rebecca D

    2015-09-30

    Perirhinal cortex (PER) has a well established role in the familiarity-based recognition of individual items and objects. For example, animals and humans with perirhinal damage are unable to distinguish familiar from novel objects in recognition memory tasks. In the normal brain, perirhinal neurons respond to novelty and familiarity by increasing or decreasing firing rates. Recent work also implicates oscillatory activity in the low-beta and low-gamma frequency bands in sensory detection, perception, and recognition. Using optogenetic methods in a spontaneous object exploration (SOR) task, we altered recognition memory performance in rats. In the SOR task, normal rats preferentially explore novel images over familiar ones. We modulated exploratory behavior in this task by optically stimulating channelrhodopsin-expressing perirhinal neurons at various frequencies while rats looked at novel or familiar 2D images. Stimulation at 30-40 Hz during looking caused rats to treat a familiar image as if it were novel by increasing time looking at the image. Stimulation at 30-40 Hz was not effective in increasing exploration of novel images. Stimulation at 10-15 Hz caused animals to treat a novel image as familiar by decreasing time looking at the image, but did not affect looking times for images that were already familiar. We conclude that optical stimulation of PER at different frequencies can alter visual recognition memory bidirectionally. Significance statement: Recognition of novelty and familiarity are important for learning, memory, and decision making. Perirhinal cortex (PER) has a well established role in the familiarity-based recognition of individual items and objects, but how novelty and familiarity are encoded and transmitted in the brain is not known. Perirhinal neurons respond to novelty and familiarity by changing firing rates, but recent work suggests that brain oscillations may also be important for recognition. In this study, we showed that stimulation of

  4. Embodied memory: unconscious smiling modulates emotional evaluation of episodic memories

    Arminjon, Mathieu

    2015-05-26

    Since Damasio introduced the somatic markers hypothesis in Damasio (1994), it has spread through the psychological community, where it is now commonly acknowledged that somatic states are a factor in producing the qualitative dimension of our experiences. Present actions are emotionally guided by those somatic states that were previously activated in similar experiences. In this model, somatic markers serve as a kind of embodied memory. Here, we test whether the manipulation of somatic markers can modulate the emotional evaluation of negative memories. Because facial feedback has been shown to be a powerful means of modifying emotional judgements, we used it to manipulate somatic markers. Participants first read a sad story in order to induce a negative emotional memory and then were asked to rate their emotions and memory about the text. Twenty-four hours later, the same participants were asked to assume a predetermined facial feedback (smiling) while reactivating their memory of the sad story. The participants were once again asked to fill in emotional and memory questionnaires about the text. Our results showed that participants who had smiled during memory reactivation later rated the text less negatively than control participants. However, the contraction of the zygomaticus muscles during memory reactivation did not have any impact on episodic memory scores. This suggests that manipulating somatic states modified emotional memory without affecting episodic memory. Thus, modulating memories through bodily states might pave the way to studying memory as an embodied function and help shape new kinds of psychotherapeutic interventions.

  5. Embodied memory: unconscious smiling modulates emotional evaluation of episodic memories

    Arminjon, Mathieu; Preissmann, Delphine; Chmetz, Florian; Duraku, Andrea; Ansermet, Franç ois; Magistretti, Pierre J.

    2015-01-01

    modulate the emotional evaluation of negative memories. Because facial feedback has been shown to be a powerful means of modifying emotional judgements, we used it to manipulate somatic markers. Participants first read a sad story in order to induce a

  6. A memory module for experimental data handling

    De Blois, J.

    1985-02-01

    A compact CAMAC memory module for experimental data handling was developed to eliminate the need of direct memory access in computer controlled measurements. When using autonomous controllers it also makes measurements more independent of the program and enlarges the available space for programs in the memory of the micro-computer. The memory module has three modes of operation: an increment-, a list- and a fifo mode. This is achieved by connecting the main parts, being: the memory (MEM), the fifo buffer (FIFO), the address buffer (BUF), two counters (AUX and ADDR) and a readout register (ROR), by an internal 24-bit databus. The time needed for databus operations is 1 μs, for measuring cycles as well as for CAMAC cycles. The FIFO provides temporary data storage during CAMAC cycles and separates the memory part from the application part. The memory is variable from 1 to 64K (24 bits) by using different types of memory chips. The application part, which forms 1/3 of the module, will be specially designed for each application and is added to the memory chian internal connector. The memory unit will be used in Mössbauer experiments and in thermal neutron scattering experiments.

  7. A memory module for experimental data handling

    Blois, J. de

    1985-01-01

    A compact CAMAC memory module for experimental data handling was developed to eliminate the need of direct memory access in computer controlled measurements. When using autonomous controllers it also makes measurements more independent of the program and enlarges the available space for programs in the memory of the micro-computer. The memory module has three modes of operation: an increment-, a list- and a fifo mode. This is achieved by connecting the main parts, being: the memory (MEM), the fifo buffer (FIFO), the address buffer (BUF), two counters (AUX and ADDR) and a readout register (ROR), by an internal 24-bit databus. The time needed for databus operations is 1 μs, for measuring cycles as well as for CAMAC cycles. The FIFO provides temporary data storage during CAMAC cycles and separates the memory part from the application part. The memory is variable from 1 to 64K (24 bits) by using different types of memory chips. The application part, which forms 1/3 of the module, will be specially designed for each application and is added to the memory by an internal connector. The memory unit will be used in Moessbauer experiments and in thermal neutron scattering experiments. (orig.)

  8. Electrothermal Frequency Modulated Resonator for Mechanical Memory

    Hafiz, Md Abdullah Al

    2016-08-18

    In this paper, we experimentally demonstrate a mechanical memory device based on the nonlinear dynamics of an electrostatically actuated microelectromechanical resonator utilizing an electrothermal frequency modulation scheme. The microstructure is deliberately fabricated as an in-plane shallow arch to achieve geometric quadratic nonlinearity. We exploit this inherent nonlinearity of the arch and drive it at resonance with minimal actuation voltage into the nonlinear regime, thereby creating softening behavior, hysteresis, and coexistence of states. The hysteretic frequency band is controlled by the electrothermal actuation voltage. Binary values are assigned to the two allowed dynamical states on the hysteretic response curve of the arch resonator with respect to the electrothermal actuation voltage. Set-and-reset operations of the memory states are performed by applying controlled dc pulses provided through the electrothermal actuation scheme, while the read-out operation is performed simultaneously by measuring the motional current through a capacitive detection technique. This novel memory device has the advantages of operating at low voltages and under room temperature. [2016-0043

  9. Electrothermal Frequency Modulated Resonator for Mechanical Memory

    Hafiz, Md Abdullah Al; Kosuru, Lakshmoji; Younis, Mohammad I.

    2016-01-01

    In this paper, we experimentally demonstrate a mechanical memory device based on the nonlinear dynamics of an electrostatically actuated microelectromechanical resonator utilizing an electrothermal frequency modulation scheme. The microstructure

  10. Interacting Brain Systems Modulate Memory Consolidation

    McIntyre, Christa K.; McGaugh, James L.; Williams, Cedric L.

    2011-01-01

    Emotional arousal influences the consolidation of long-term memory. This review discusses experimental approaches and relevant findings that provide the foundation for current understanding of coordinated interactions between arousal activated peripheral hormones and the brain processes that modulate memory formation. Rewarding or aversive experiences release the stress hormones epinephrine (adrenalin) and glucocorticoids from the adrenal glands into the bloodstream. The effect of these hormones on memory consolidation depends upon binding of norepinephrine to beta-adrenergic receptors in the basolateral complex of the amygdala (BLA). Much evidence indicates that the stress hormones influence release of norepinephrine in the BLA through peripheral actions on the vagus nerve which stimulates, through polysynaptic connections, cells of the locus coeruleus to release norepinephrine. The BLA influences memory storage by actions on synapses, distributed throughout the brain, that are engaged in sensory and cognitive processing at the time of amygdala activation. The implications of the activation of these stress-activated memory processes are discussed in relation to stress-related memory disorders. PMID:22085800

  11. Fast, Accurate Memory Architecture Simulation Technique Using Memory Access Characteristics

    小野, 貴継; 井上, 弘士; 村上, 和彰

    2007-01-01

    This paper proposes a fast and accurate memory architecture simulation technique. To design memory architecture, the first steps commonly involve using trace-driven simulation. However, expanding the design space makes the evaluation time increase. A fast simulation is achieved by a trace size reduction, but it reduces the simulation accuracy. Our approach can reduce the simulation time while maintaining the accuracy of the simulation results. In order to evaluate validity of proposed techniq...

  12. Value conditioning modulates visual working memory processes.

    Thomas, Paul M J; FitzGibbon, Lily; Raymond, Jane E

    2016-01-01

    Learning allows the value of motivationally salient events to become associated with stimuli that predict those events. Here, we asked whether value associations could facilitate visual working memory (WM), and whether such effects would be valence dependent. Our experiment was specifically designed to isolate value-based effects on WM from value-based effects on selective attention that might be expected to bias encoding. In a simple associative learning task, participants learned to associate the color of tinted faces with gaining or losing money or neither. Tinted faces then served as memoranda in a face identity WM task for which previously learned color associations were irrelevant and no monetary outcomes were forthcoming. Memory was best for faces with gain-associated tints, poorest for faces with loss-associated tints, and average for faces with no-outcome-associated tints. Value associated with 1 item in the WM array did not modulate memory for other items in the array. Eye movements when studying faces did not depend on the valence of previously learned color associations, arguing against value-based biases being due to differential encoding. This valence-sensitive value-conditioning effect on WM appears to result from modulation of WM maintenance processes. (c) 2015 APA, all rights reserved).

  13. Multicarrier Modulation Techniques for 5G Communications

    QIANYU JIN

    2018-01-01

    This thesis focuses on multicarrier modulation techniques for 5G wireless communications. We study different properties of current multicarrier modulation techniques and propose methodologies to improve them in order to meet the demands of 5G wireless, e.g., low out-of-band radiation, low latency, relaxed synchronization, and stable performance against phase noise with low complexity over a wireless channel.

  14. Working memory load modulates microsaccadic rate.

    Dalmaso, Mario; Castelli, Luigi; Scatturin, Pietro; Galfano, Giovanni

    2017-03-01

    Microsaccades are tiny eye movements that individuals perform unconsciously during fixation. Despite that the nature and the functions of microsaccades are still lively debated, recent evidence has shown an association between these micro eye movements and higher order cognitive processes. Here, in two experiments, we specifically focused on working memory and addressed whether differential memory load could be reflected in a modulation of microsaccade dynamics. In Experiment 1, participants memorized a numerical sequence composed of either two (low-load condition) or five digits (high-load condition), appearing at fixation. The results showed a reduction in the microsaccadic rate in the high-load compared to the low-load condition. In Experiment 2, five red or green digits were always presented at fixation. Participants either memorized the color (low-load condition) or the five digits (high-load condition). Hence, visual stimuli were exactly the same in both conditions. Consistent with Experiment 1, microsaccadic rate was lower in the high-load than in the low-load condition. Overall, these findings reveal that an engagement of working memory can have an impact on microsaccadic rate, consistent with the view that microsaccade generation is pervious to top-down processes.

  15. Subthalamic stimulation differentially modulates declarative and nondeclarative memory.

    Hälbig, Thomas D; Gruber, Doreen; Kopp, Ute A; Scherer, Peter; Schneider, Gerd-Helge; Trottenberg, Thomas; Arnold, Guy; Kupsch, Andreas

    2004-03-01

    Declarative memory has been reported to rely on the medial temporal lobe system, whereas non-declarative memory depends on basal ganglia structures. We investigated the functional role of the subthalamic nucleus (STN), a structure closely connected with the basal ganglia for both types of memory. Via deep brain high frequency stimulation (DBS) we manipulated neural activity of the STN in humans. We found that DBS-STN differentially modulated memory performance: declarative memory was impaired, whereas non-declarative memory was improved in the presence of STN-DBS indicating a specific role of the STN in the activation of memory systems. Copyright 2004 Lippincott Williams & Wilkins

  16. Local sleep spindle modulations in relation to specific memory cues

    Cox, R.; Hofman, W.F.; de Boer, M.; Talamini, L.M.

    2014-01-01

    Sleep spindles have been connected to memory processes in various ways. In addition, spindles appear to be modulated at the local cortical network level. We investigated whether cueing specific memories during sleep leads to localized spindle modulations in humans. During learning of word-location

  17. Selection History Modulates Working Memory Capacity

    Bo-Cheng Kuo

    2016-10-01

    Full Text Available Recent studies have shown that past selection history affects the allocation of attention on target selection. However, it is unclear whether context-driven selection history can modulate the efficacy of attention allocation on working memory (WM representations. This study tests the influences of selection history on WM capacity. A display of one item (low load or three/four items (high load was shown for the participants to hold in WM in a delayed response task. Participants then judged whether a probe item was in the memory display or not. Selection history was defined as the number of items attended across trials in the task context within a block, manipulated by the stimulus set-size in the contexts with fewer possible stimuli (4-item or 5-item context or more possible stimuli (8-item or 9-item context from which the memorized content was selected. The capacity measure (i.e. the K parameter was estimated to reflect the number of items that can be held in WM. Across four behavioral experiments, the results revealed that the capacity was significantly reduced in the context with more possible stimuli relative to the context with fewer possible stimuli. Moreover, the reduction in capacity was significant for high WM load and not observed when the focus was on only a single item. Together, these findings indicate that context-driven selection history and focused attention influence WM capacity.

  18. Social memories in rodents: Methods, mechanisms and modulation by stress

    van der Kooij MA; Sandi C.

    2011-01-01

    Intact social memory forms the basis of meaningful interactions between individuals. Many factors can modulate the quality of social memory, and these have been studied in detail in rodents. Social memory, however, cannot be considered a single entity. The term social memory reflects different processes, such as social recognition of a novel conspecific individual and social learning (or 'learning from others'). This review summarizes the findings obtained with behavioral paradigms that were ...

  19. Task Oriented Evaluation of Module Extraction Techniques

    Palmisano, Ignazio; Tamma, Valentina; Payne, Terry; Doran, Paul

    Ontology Modularization techniques identify coherent and often reusable regions within an ontology. The ability to identify such modules, thus potentially reducing the size or complexity of an ontology for a given task or set of concepts is increasingly important in the Semantic Web as domain ontologies increase in terms of size, complexity and expressivity. To date, many techniques have been developed, but evaluation of the results of these techniques is sketchy and somewhat ad hoc. Theoretical properties of modularization algorithms have only been studied in a small number of cases. This paper presents an empirical analysis of a number of modularization techniques, and the modules they identify over a number of diverse ontologies, by utilizing objective, task-oriented measures to evaluate the fitness of the modules for a number of statistical classification problems.

  20. Memory-Modulation: Self-Improvement or Self-Depletion?

    Lavazza, Andrea

    2018-01-01

    Autobiographical memory is fundamental to the process of self-construction. Therefore, the possibility of modifying autobiographical memories, in particular with memory-modulation and memory-erasing, is a very important topic both from the theoretical and from the practical point of view. The aim of this paper is to illustrate the state of the art of some of the most promising areas of memory-modulation and memory-erasing, considering how they can affect the self and the overall balance of the "self and autobiographical memory" system. Indeed, different conceptualizations of the self and of personal identity in relation to autobiographical memory are what makes memory-modulation and memory-erasing more or less desirable. Because of the current limitations (both practical and ethical) to interventions on memory, I can only sketch some hypotheses. However, it can be argued that the choice to mitigate painful memories (or edit memories for other reasons) is somehow problematic, from an ethical point of view, according to some of the theories of the self and personal identity in relation to autobiographical memory, in particular for the so-called narrative theories of personal identity, chosen here as the main case of study. Other conceptualizations of the "self and autobiographical memory" system, namely the constructivist theories, do not have this sort of critical concerns. However, many theories rely on normative (and not empirical) conceptions of the self: for them, the actions aimed at mitigating or removing specific (negative) memories can be seen either as an improvement or as a depletion or impairment of the self.

  1. Chromaticity tracking using a phase modulation technique

    Tan, C.Y.; Fermilab

    2007-01-01

    In the classical chromaticity measurement technique, chromaticity is measured by measuring the change in betatron tune as the RF frequency is varied. This paper will describe a novel way of measuring chromaticity: we will phase modulate the RF with a known sine wave and then phase demodulate the betatron frequency. The result is a line in Fourier space which corresponds to the frequency of our sine wave modulation. The peak of this sine wave is proportional to chromaticity. For this technique to work, a tune tracker PLL system is required because it supplies the betatron carrier frequency. This method has been tested in the Tevatron and we will show the results here

  2. Optical rangefinding applications using communications modulation technique

    Caplan, William D.; Morcom, Christopher John

    2010-10-01

    A novel range detection technique combines optical pulse modulation patterns with signal cross-correlation to produce an accurate range estimate from low power signals. The cross-correlation peak is analyzed by a post-processing algorithm such that the phase delay is proportional to the range to target. This technique produces a stable range estimate from noisy signals. The advantage is higher accuracy obtained with relatively low optical power transmitted. The technique is useful for low cost, low power and low mass sensors suitable for tactical use. The signal coding technique allows applications including IFF and battlefield identification systems.

  3. Axially modulated arch resonator for logic and memory applications

    Hafiz, Md Abdullah Al; Tella, Sherif Adekunle; Alcheikh, Nouha; Fariborzi, Hossein; Younis, Mohammad I.

    2018-01-01

    We demonstrate reconfigurable logic and random access memory devices based on an axially modulated clamped-guided arch resonator. The device is electrostatically actuated and the motional signal is capacitively sensed, while the resonance frequency

  4. Memory-Modulation: Self-Improvement or Self-Depletion?

    Andrea Lavazza

    2018-04-01

    Full Text Available Autobiographical memory is fundamental to the process of self-construction. Therefore, the possibility of modifying autobiographical memories, in particular with memory-modulation and memory-erasing, is a very important topic both from the theoretical and from the practical point of view. The aim of this paper is to illustrate the state of the art of some of the most promising areas of memory-modulation and memory-erasing, considering how they can affect the self and the overall balance of the “self and autobiographical memory” system. Indeed, different conceptualizations of the self and of personal identity in relation to autobiographical memory are what makes memory-modulation and memory-erasing more or less desirable. Because of the current limitations (both practical and ethical to interventions on memory, I can only sketch some hypotheses. However, it can be argued that the choice to mitigate painful memories (or edit memories for other reasons is somehow problematic, from an ethical point of view, according to some of the theories of the self and personal identity in relation to autobiographical memory, in particular for the so-called narrative theories of personal identity, chosen here as the main case of study. Other conceptualizations of the “self and autobiographical memory” system, namely the constructivist theories, do not have this sort of critical concerns. However, many theories rely on normative (and not empirical conceptions of the self: for them, the actions aimed at mitigating or removing specific (negative memories can be seen either as an improvement or as a depletion or impairment of the self.

  5. Activating attachment representations during memory retrieval modulates intrusive traumatic memories.

    Bryant, Richard A; Chan, Iris

    2017-10-01

    Although priming mental representations of attachment security reduces arousal, research has not examined the effect of attachment on the retrieval of emotionally arousing memories. This study investigated the effect of priming attachment security on the retrieval of emotional memories. Seventy-five participants viewed negative and neutral images, and two days later received either an attachment prime or a control prime immediately prior to free recall of the images. Two days later, participants reported how frequently they experienced intrusions of the negative images. The attachment group had less distress, and reported fewer subsequent intrusions than the control group. Attachment style moderated these effects such that individuals with an avoidant attachment style were not impacted by the attachment prime. These findings suggest that priming attachment security decreases distress during memory reactivation, and this may reduce subsequent intrusive memories. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Axially modulated arch resonator for logic and memory applications

    Hafiz, Md Abdullah Al

    2018-01-17

    We demonstrate reconfigurable logic and random access memory devices based on an axially modulated clamped-guided arch resonator. The device is electrostatically actuated and the motional signal is capacitively sensed, while the resonance frequency is modulated through an axial electrostatic force from the guided side of the microbeam. A multi-physics finite element model is used to verify the effectiveness of the axial modulation. We present two case studies: first, a reconfigurable two-input logic gate based on the linear resonance frequency modulation, and second, a memory element based on the hysteretic frequency response of the resonator working in the nonlinear regime. The energy consumptions of the device for both logic and memory operations are in the range of picojoules, promising for energy efficient alternative computing paradigm.

  7. Neural mechanism underlying autobiographical memory modulated by remoteness and emotion

    Ge, Ruiyang; Fu, Yan; Wang, DaHua; Yao, Li; Long, Zhiying

    2012-03-01

    Autobiographical memory is the ability to recollect past events from one's own life. Both emotional tone and memory remoteness can influence autobiographical memory retrieval along the time axis of one's life. Although numerous studies have been performed to investigate brain regions involved in retrieving processes of autobiographical memory, the effect of emotional tone and memory age on autobiographical memory retrieval remains to be clarified. Moreover, whether the involvement of hippocampus in consolidation of autobiographical events is time dependent or independent has been controversial. In this study, we investigated the effect of memory remoteness (factor1: recent and remote) and emotional valence (factor2: positive and negative) on neural correlates underlying autobiographical memory by using functional magnetic resonance imaging (fMRI) technique. Although all four conditions activated some common regions known as "core" regions in autobiographical memory retrieval, there are some other regions showing significantly different activation for recent versus remote and positive versus negative memories. In particular, we found that bilateral hippocampal regions were activated in the four conditions regardless of memory remoteness and emotional valence. Thus, our study confirmed some findings of previous studies and provided further evidence to support the multi-trace theory which believes that the role of hippocampus involved in autobiographical memory retrieval is time-independent and permanent in memory consolidation.

  8. Increment memory module for spectrometric data recording

    Zhuchkov, A.A.; Myagkikh, A.I.

    1988-01-01

    Incremental memory unit designed to input differential energy spectra of nuclear radiation is described. ROM application as incremental device has allowed to reduce the number of elements and do simplify information readout from the unit. 12-bit 2048 channels present memory unit organization. The device is connected directly with the bus of microprocessor systems similar to KR 580. Incrementation maximal time constitutes 3 mks. It is possible to use this unit in multichannel counting mode

  9. Emotional Modulation of Learning and Memory: Pharmacological Implications.

    LaLumiere, Ryan T; McGaugh, James L; McIntyre, Christa K

    2017-07-01

    Memory consolidation involves the process by which newly acquired information becomes stored in a long-lasting fashion. Evidence acquired over the past several decades, especially from studies using post-training drug administration, indicates that emotional arousal during the consolidation period influences and enhances the strength of the memory and that multiple different chemical signaling systems participate in this process. The mechanisms underlying the emotional influences on memory involve the release of stress hormones and activation of the basolateral amygdala, which work together to modulate memory consolidation. Moreover, work suggests that this amygdala-based memory modulation occurs with numerous types of learning and involves interactions with many different brain regions to alter consolidation. Additionally, studies suggest that emotional arousal and amygdala activity in particular influence synaptic plasticity and associated proteins in downstream brain regions. This review considers the historical understanding for memory modulation and cellular consolidation processes and examines several research areas currently using this foundational knowledge to develop therapeutic treatments. Copyright © 2017 by The American Society for Pharmacology and Experimental Therapeutics.

  10. The role of overt attention in emotion-modulated memory.

    Riggs, Lily; McQuiggan, Douglas A; Farb, Norman; Anderson, Adam K; Ryan, Jennifer D

    2011-08-01

    The presence of emotional stimuli results in a central/peripheral tradeoff effect in memory: memory for central details is enhanced at the cost of peripheral items. It has been assumed that emotion-modulated differences in memory are the result of differences in attention, but this has not been tested directly. The present experiment used eye movement monitoring as an index of overt attention allocation and mediation analysis to determine whether differences in attention were related to subsequent memory. Participants viewed negative and neutral scenes surrounded by three neutral objects and were then given a recognition memory test. The results revealed evidence in support of a central/peripheral tradeoff in both attention and memory. However, contrary with previous assumptions, whereas attention partially mediated emotion-enhanced memory for central pictures, it did not explain the entire relationship. Further, although centrally presented emotional stimuli led to decreased number of eye fixations toward the periphery, these differences in viewing did not contribute to emotion-impaired memory for specific details pertaining to the periphery. These findings suggest that the differential influence of negative emotion on central versus peripheral memory may result from other cognitive influences in addition to overt visual attention or on postencoding processes. 2011 APA, all rights reserved

  11. Cholinergic modulation of the hippocampal region and memory function.

    Haam, Juhee; Yakel, Jerrel L

    2017-08-01

    Acetylcholine (ACh) plays an important role in memory function and has been implicated in aging-related dementia, in which the impairment of hippocampus-dependent learning strongly manifests. Cholinergic neurons densely innervate the hippocampus, mediating the formation of episodic as well as semantic memory. Here, we will review recent findings on acetylcholine's modulation of memory function, with a particular focus on hippocampus-dependent learning, and the circuits involved. In addition, we will discuss the complexity of ACh actions in memory function to better understand the physiological role of ACh in memory. This is an article for the special issue XVth International Symposium on Cholinergic Mechanisms. © 2017 International Society for Neurochemistry.

  12. Circadian modulation of short-term memory in Drosophila.

    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.

  13. Memory Based Machine Intelligence Techniques in VLSI hardware

    James, Alex Pappachen

    2012-01-01

    We briefly introduce the memory based approaches to emulate machine intelligence in VLSI hardware, describing the challenges and advantages. Implementation of artificial intelligence techniques in VLSI hardware is a practical and difficult problem. Deep architectures, hierarchical temporal memories and memory networks are some of the contemporary approaches in this area of research. The techniques attempt to emulate low level intelligence tasks and aim at providing scalable solutions to high ...

  14. Dopamine Receptor Genes Modulate Associative Memory in Old Age.

    Papenberg, Goran; Becker, Nina; Ferencz, Beata; Naveh-Benjamin, Moshe; Laukka, Erika J; Bäckman, Lars; Brehmer, Yvonne

    2017-02-01

    Previous research shows that associative memory declines more than item memory in aging. Although the underlying mechanisms of this selective impairment remain poorly understood, animal and human data suggest that dopaminergic modulation may be particularly relevant for associative binding. We investigated the influence of dopamine (DA) receptor genes on item and associative memory in a population-based sample of older adults (n = 525, aged 60 years), assessed with a face-scene item associative memory task. The effects of single-nucleotide polymorphisms of DA D1 (DRD1; rs4532), D2 (DRD2/ANKK1/Taq1A; rs1800497), and D3 (DRD3/Ser9Gly; rs6280) receptor genes were examined and combined into a single genetic score. Individuals carrying more beneficial alleles, presumably associated with higher DA receptor efficacy (DRD1 C allele; DRD2 A2 allele; DRD3 T allele), performed better on associative memory than persons with less beneficial genotypes. There were no effects of these genes on item memory or other cognitive measures, such as working memory, executive functioning, fluency, and perceptual speed, indicating a selective association between DA genes and associative memory. By contrast, genetic risk for Alzheimer disease (AD) was associated with worse item and associative memory, indicating adverse effects of APOE ε4 and a genetic risk score for AD (PICALM, BIN1, CLU) on episodic memory in general. Taken together, our results suggest that DA may be particularly important for associative memory, whereas AD-related genetic variations may influence overall episodic memory in older adults without dementia.

  15. Cannabinoids modulate hippocampal memory and plasticity.

    Abush, Hila; Akirav, Irit

    2010-10-01

    Considerable evidence demonstrates that cannabinoid agonists impair whereas cannabinoid antagonists improve memory and plasticity. However, recent studies suggest that the effects of cannabinoids on learning do not necessarily follow these simple patterns, particularly when emotional memory processes are involved. We investigated the involvement of the cannabinoid system in hippocampal learning and plasticity using the fear-related inhibitory avoidance (IA) and the non-fear-related spatial learning paradigms, and cellular models of learning and memory, i.e., long-term potentiation (LTP) and long-term depression (LTD). We found that microinjection into the CA1 of the CB1/CB2 receptor agonist WIN55,212-2 (5 μg/side) and an inhibitor of endocannabinoid reuptake and breakdown AM404 (200 ng/side) facilitated the extinction of IA, while the CB1 receptor antagonist AM251 (6 ng/side) impaired it. WIN55,212-2 and AM251 did not affect IA conditioning, while AM404 enhanced it, probably due to a drug-induced increase in pain sensitivity. However, in the water maze, systemic or local CA1 injections of AM251, WIN55,212-2, and AM404 all impaired spatial learning. We also found that i.p. administration of WIN55,212-2 (0.5 mg/kg), AM404 (10 mg/kg), and AM251 (2 mg/kg) impaired LTP in the Schaffer collateral-CA1 projection, whereas AM404 facilitated LTD. Our findings suggest diverse effects of the cannabinoid system on CA1 memory and plasticity that cannot be categorized simply into an impairing or an enhancing effect of cannabinoid activation and deactivation, respectively. Moreover, they provide preclinical support for the suggestion that targeting the endocannabinoid system may aid in the treatment of disorders associated with impaired extinction-like processes, such as post-traumatic stress disorder. © 2009 Wiley-Liss, Inc.

  16. Nicotine Modulates the Long-Lasting Storage of Fear Memory

    Lima, Ramon H.; Radiske, Andressa; Kohler, Cristiano A.; Gonzalez, Maria Carolina; Bevilaqua, Lia R.; Rossato, Janine I.; Medina, Jorge H.; Cammarota, Martin

    2013-01-01

    Late post-training activation of the ventral tegmental area (VTA)-hippocampus dopaminergic loop controls the entry of information into long-term memory (LTM). Nicotinic acetylcholine receptors (nAChR) modulate VTA function, but their involvement in LTM storage is unknown. Using pharmacological and behavioral tools, we found that…

  17. NPY2-receptor variation modulates iconic memory processes.

    Arning, Larissa; Stock, Ann-Kathrin; Kloster, Eugen; Epplen, Jörg T; Beste, Christian

    2014-08-01

    Sensory memory systems are modality-specific buffers that comprise information about external stimuli, which represent the earliest stage of information processing. While these systems have been the subject of cognitive neuroscience research for decades, little is known about the neurobiological basis of sensory memory. However, accumulating evidence suggests that the glutamatergic system and systems influencing glutamatergic neural transmission are important. In the current study we examine if functional promoter variations in neuropeptide Y (NPY) and its receptor gene NPY2R affect iconic memory processes using a partial report paradigm. We found that iconic memory decayed much faster in individuals carrying the rare promoter NPY2R G allele which is associated with increased expression of the Y2 receptor. Possibly this effect is due to altered presynaptic inhibition of glutamate release, known to be modulated by Y2 receptors. Altogether, our results provide evidence that the functionally relevant single nucleotide polymorphism (SNP) in the NPY2R promoter gene affect circumscribed processes of early sensory processing, i.e. only the stability of information in sensory memory buffers. This leads us to suggest that especially the stability of information in sensory memory buffers depends on glutamatergic neural transmission and factors modulating glutamatergic turnover. Copyright © 2014 Elsevier B.V. and ECNP. All rights reserved.

  18. Modulation of working memory updating: Does long-term memory lexical association matter?

    Artuso, Caterina; Palladino, Paola

    2016-02-01

    The aim of the present study was to investigate how working memory updating for verbal material is modulated by enduring properties of long-term memory. Two coexisting perspectives that account for the relation between long-term representation and short-term performance were addressed. First, evidence suggests that performance is more closely linked to lexical properties, that is, co-occurrences within the language. Conversely, other evidence suggests that performance is linked more to long-term representations which do not entail lexical/linguistic representations. Our aim was to investigate how these two kinds of long-term memory associations (i.e., lexical or nonlexical) modulate ongoing working memory activity. Therefore, we manipulated (between participants) the strength of the association in letters based on either frequency of co-occurrences (lexical) or contiguity along the sequence of the alphabet (nonlexical). Results showed a cost in working memory updating for strongly lexically associated stimuli only. Our findings advance knowledge of how lexical long-term memory associations between consonants affect working memory updating and, in turn, contribute to the study of factors which impact the updating process across memory systems.

  19. Endocannabinoids in the rat basolateral amygdala enhance memory consolidation and enable glucocorticoid modulation of memory

    Campolongo, Patrizia; Roozendaal, Benno; Trezza, Viviana; Hauer, Daniela; Schelling, Gustav; McGaugh, James L.; Cuomo, Vincenzo

    2009-01-01

    Extensive evidence indicates that the basolateral complex of the amygdala (BLA) modulates the consolidation of memories for emotionally arousing experiences, an effect that involves the activation of the glucocorticoid system. Because the BLA expresses high densities of cannabinoid CB1 receptors, the present experiments investigated whether the endocannabinoid system in the BLA influences memory consolidation and whether glucocorticoids interact with this system. The CB1 receptor agonist WIN5...

  20. Intelligent Memory Module Overcomes Harsh Environments

    2008-01-01

    Solar cells, integrated circuits, and sensors are essential to manned and unmanned space flight and exploration, but such systems are highly susceptible to damage from radiation. Especially problematic, the Van Allen radiation belts encircle Earth in concentric radioactive tori at distances from about 6,300 to 38,000 km, though the inner radiation belt can dip as low as 700 km, posing a severe hazard to craft and humans leaving Earth s atmosphere. To avoid this radiation, the International Space Station and space shuttles orbit at altitudes between 275 and 460 km, below the belts range, and Apollo astronauts skirted the edge of the belts to minimize exposure, passing swiftly through thinner sections of the belts and thereby avoiding significant side effects. This radiation can, however, prove detrimental to improperly protected electronics on satellites that spend the majority of their service life in the harsh environment of the belts. Compact, high-performance electronics that can withstand extreme environmental and radiation stress are thus critical to future space missions. Increasing miniaturization of electronics addresses the need for lighter weight in launch payloads, as launch costs put weight at a premium. Likewise, improved memory technologies have reduced size, cost, mass, power demand, and system complexity, and improved high-bandwidth communication to meet the data volume needs of the next-generation high-resolution sensors. This very miniaturization, however, has exacerbated system susceptibility to radiation, as the charge of ions may meet or exceed that of circuitry, overwhelming the circuit and disrupting operation of a satellite. The Hubble Space Telescope, for example, must turn off its sensors when passing through intense radiation to maintain reliable operation. To address the need for improved data quality, additional capacity for raw and processed data, ever-increasing resolution, and radiation tolerance, NASA spurred the development of the

  1. Photoacoustic investigation of QCL modulation techniques

    Germer, M; Wolff, M

    2010-01-01

    High detection sensitivity and spectral selectivity is important for gas analysers to identify the measured compound and to detect low concentrations. We investigated three different modulation methods - pulse gate modulation, pulse frequency modulation and chopper modulation - for a new pulsed quantum cascade laser based photoacoustic sensor. The spectral selectivity and the detection limit for the three modulation methods are compared by measuring nitric oxide absorption lines and different concentrations. The highest detection sensitivity of 70 ppb was achieved with pulse gate modulation but at the lowest spectral resolution. The highest spectral resolution was achieved with chopper modulation but at the lowest detection sensitivity. It is demonstrated that for the three modulation methods a compromise has to be made between selectivity and sensitivity for each measuring task.

  2. Endocannabinoids in the rat basolateral amygdala enhance memory consolidation and enable glucocorticoid modulation of memory

    Campolongo, Patrizia; Roozendaal, Benno; Trezza, Viviana; Hauer, Daniela; Schelling, Gustav; McGaugh, James L.; Cuomo, Vincenzo

    2009-01-01

    Extensive evidence indicates that the basolateral complex of the amygdala (BLA) modulates the consolidation of memories for emotionally arousing experiences, an effect that involves the activation of the glucocorticoid system. Because the BLA expresses high densities of cannabinoid CB1 receptors,

  3. Vagus nerve stimulation modulates visceral pain-related affective memory.

    Zhang, Xu; Cao, Bing; Yan, Ni; Liu, Jin; Wang, Jun; Tung, Vivian Oi Vian; Li, Ying

    2013-01-01

    Within a biopsychosocial model of pain, pain is seen as a conscious experience modulated by mental, emotional and sensory mechanisms. Recently, using a rodent visceral pain assay that combines the colorectal distension (CRD) model with the conditioned place avoidance (CPA) paradigms, we measured a learned behavior that directly reflects the affective component of visceral pain, and showed that perigenual anterior cingulate cortex (pACC) activation is critical for memory processing involved in long-term visceral affective state and prediction of aversive stimuli by contextual cue. Electrical vagus nerve stimulation (VNS) has become an established therapy for treatment-resistant epilepsy. VNS has also been shown to enhance memory performance in rats and humans. High-intensity VNS (400 μA) immediately following conditional training significantly increases the CRD-induced CPA scores, and enhanced the pain affective memory retention. In contrast, VNS (400 μA) had no effect on CPA induced by non-nociceptive aversive stimulus (U69,593). Low-intensity VNS (40 μA) had no effect on CRD-induced CPA. Electrophysiological recording showed that VNS (400 μA) had no effect on basal and CRD-induced ACC neuronal firing. Further, VNS did not alter CRD-induced visceral pain responses suggesting high intensity VNS facilitates visceral pain aversive memory independent of sensory discriminative aspects of visceral pain processing. The findings that vagus nerve stimulation facilities visceral pain-related affective memory underscore the importance of memory in visceral pain perception, and support the theory that postprandial factors may act on vagal afferents to modulate ongoing nature of visceral pain-induced affective disorder observed in the clinic, such as irritable bowel syndrome. Copyright © 2012 Elsevier B.V. All rights reserved.

  4. Dorsolateral prefrontal cortex, working memory and episodic memory processes: insight through transcranial magnetic stimulation techniques

    Michela Balconi

    2013-01-01

    The ability to recall and recognize facts we experienced in the past is based on a complex mechanism in which several cerebral regions are implicated.Neuroimaging and lesion studies agree in identifying the frontal lobe as a crucial structure for memory processes,and in particular for working memory and episodic memory and their relationships.Furthermore,with the introduction of transcranial magnetic stimulation (TMS) a new way was proposed to investigate the relationships between brain correlates,memory functions and behavior.The aim of this review is to present the main findings that have emerged from experiments which used the TMS technique for memory analysis.They mainly focused on the role of the dorsolateral prefrontal cortex in memory process.Furthermore,we present state-of-the-art evidence supporting a possible use of TMS in the clinic.Specifically we focus on the treatment of memory deficits in depression and anxiety disorders.

  5. A Neuroanatomical Model of Prefrontal Inhibitory Modulation of Memory Retrieval

    Depue, Brendan E.

    2012-01-01

    Memory of past experience is essential for guiding goal-related behavior. Being able to control accessibility of memory through modulation of retrieval enables humans to flexibly adapt to their environment. Understanding the specific neural pathways of how this control is achieved has largely eluded cognitive neuroscience. Accordingly, in the current paper I review literature that examines the overt control over retrieval in order to reduce accessibility. I first introduce three hypotheses of inhibition of retrieval. These hypotheses involve: i) attending to other stimuli as a form of diversionary attention, ii) inhibiting the specific individual neural representation of the memory, and iii) inhibiting the hippocampus and retrieval process more generally to prevent reactivation of the representation. I then analyze literature taken from the White Bear Suppression, Directed Forgetting and Think/No-Think tasks to provide evidence for these hypotheses. Finally, a neuroanatomical model is developed to indicate three pathways from PFC to the hippocampal complex that support inhibition of memory retrieval. Describing these neural pathways increases our understanding of control over memory in general. PMID:22374224

  6. Attention, working memory, and phenomenal experience of WM content: memory levels determined by different types of top-down modulation

    Jacob, Jane; Jacobs, Christianne; Silvanto, Juha

    2015-01-01

    What is the role of top-down attentional modulation in consciously accessing working memory (WM) content? In influential WM models, information can exist in different states, determined by allocation of attention; placing the original memory representation in the center of focused attention gives rise to conscious access. Here we discuss various lines of evidence indicating that such attentional modulation is not sufficient for memory content to be phenomenally experienced. We propose that, i...

  7. Modulation of multiple memory systems: from neurotransmitters to metabolic substrates.

    Gold, Paul E; Newman, Lori A; Scavuzzo, Claire J; Korol, Donna L

    2013-11-01

    This article reviews evidence showing that neurochemical modulators can regulate the relative participation of the hippocampus and striatum in learning and memory tasks. For example, relative release of acetylcholine increases in the hippocampus and striatum reflects the relative engagement of these brain systems during learning of place and response tasks. Acetylcholine release is regulated in part by available brain glucose levels, which themselves are dynamically modified during learning. Recent findings suggest that glucose acts through astrocytes to deliver lactate to neurons. Brain glycogen is contained in astrocytes and provides a capacity to deliver energy substrates to neurons when needed, a need that can be generated by training on tasks that target hippocampal and striatal processing mechanisms. These results integrate an increase in blood glucose after epinephrine release from the adrenal medulla with provision of brain energy substrates, including lactate released from astrocytes. Together, the availability of peripheral and central energy substrates regulate the processing of learning and memory within and across multiple neural systems. Dysfunctions of the physiological steps that modulate memory--from hormones to neurotransmitters to metabolic substrates--may contribute importantly to some of the cognitive impairments seen during normal aging and during neurodegenerative diseases. Copyright © 2013 Wiley Periodicals, Inc.

  8. Identity modulates short-term memory for facial emotion.

    Galster, Murray; Kahana, Michael J; Wilson, Hugh R; Sekuler, Robert

    2009-12-01

    For some time, the relationship between processing of facial expression and facial identity has been in dispute. Using realistic synthetic faces, we reexamined this relationship for both perception and short-term memory. In Experiment 1, subjects tried to identify whether the emotional expression on a probe stimulus face matched the emotional expression on either of two remembered faces that they had just seen. The results showed that identity strongly influenced recognition short-term memory for emotional expression. In Experiment 2, subjects' similarity/dissimilarity judgments were transformed by multidimensional scaling (MDS) into a 2-D description of the faces' perceptual representations. Distances among stimuli in the MDS representation, which showed a strong linkage of emotional expression and facial identity, were good predictors of correct and false recognitions obtained previously in Experiment 1. The convergence of the results from Experiments 1 and 2 suggests that the overall structure and configuration of faces' perceptual representations may parallel their representation in short-term memory and that facial identity modulates the representation of facial emotion, both in perception and in memory. The stimuli from this study may be downloaded from http://cabn.psychonomic-journals.org/content/supplemental.

  9. Attention, working memory, and phenomenal experience of WM content: memory levels determined by different types of top-down modulation.

    Jacob, Jane; Jacobs, Christianne; Silvanto, Juha

    2015-01-01

    What is the role of top-down attentional modulation in consciously accessing working memory (WM) content? In influential WM models, information can exist in different states, determined by allocation of attention; placing the original memory representation in the center of focused attention gives rise to conscious access. Here we discuss various lines of evidence indicating that such attentional modulation is not sufficient for memory content to be phenomenally experienced. We propose that, in addition to attentional modulation of the memory representation, another type of top-down modulation is required: suppression of all incoming visual information, via inhibition of early visual cortex. In this view, there are three distinct memory levels, as a function of the top-down control associated with them: (1) Nonattended, nonconscious associated with no attentional modulation; (2) attended, phenomenally nonconscious memory, associated with attentional enhancement of the actual memory trace; (3) attended, phenomenally conscious memory content, associated with enhancement of the memory trace and top-down suppression of all incoming visual input.

  10. Antigen modulation of the immune response. III. Evaluation of the hypothetical short-lived memory cell

    Feldbush, T.L.; Lande, I.; Bryan, B.; O'Neill, E.

    1974-01-01

    The putative short-lived memory cells, whose existence has been suggested by the results of secondary adoptive transfer experiments, were investigated. On the basis of the following evidences we have concluded that the short-lived memory cell is probably an artifact of the adoptive transfer technique: when immune thoracic duct lymphocytes, known to consist predominantly of long-lived memory cells, were transferred to irradiated recipients and challenged at various times after transfer, approximately 80 to 90 percent of the initial response was absent by Day 14 challenge; preirradiating adoptive recipients with increasing dose of x-irradiation tended to lengthen the observed half life of memory cells; single or multiple treatments of immune donors with 0.3 mg Vinblastin before transfer resulted in neither a depression of the initial secondary response nor an alteration in the rate of decline of the memory potential; reconstitution of irradiated hosts with normal spleen cells one day before transfer of memory cells and challenge resulted in inhibition of the adoptive secondary response; and the transfer of memory cells to antigen free intermediate hosts, in which they were allowed to reside for one day or fourteen days before transfer to irradiated recipients, resulted in only a slight decline in their capacity to respond. We propose that the rapid decline of memory potential in adoptive recipients challenged at various times after transfer is due to modulating effects by the hosts as it recovers from irradiation. These effects may be the result of cell crowding or the loss of irradiation-produced stimulatory factors. The relevance of these findings to adoptive transfer systems in general and the secondary response of intact animals is discussed

  11. Dimmable electronic ballasts by variable power density modulation technique

    Borekci, Selim; Kesler, Selami

    2014-11-01

    Dimming can be accomplished commonly by switching frequency and pulse density modulation techniques and a variable inductor. In this study, a variable power density modulation (VPDM) control technique is proposed for dimming applications. A fluorescent lamp is operated in several states to meet the desired lamp power in a modulation period. The proposed technique has the same advantages of magnetic dimming topologies have. In addition, a unique and flexible control technique can be achieved. A prototype dimmable electronic ballast is built and experiments related to it have been conducted. As a result, a 36WT8 fluorescent lamp can be driven for a desired lamp power from several alternatives without modulating the switching frequency.

  12. Transcranial direct current stimulation over the right DLPFC selectively modulates subprocesses in working memory

    Jiarui Wang

    2018-05-01

    Full Text Available Background Working memory, as a complex system, consists of two independent components: manipulation and maintenance process, which are defined as executive control and storage process. Previous studies mainly focused on the overall effect of transcranial direct current stimulation (tDCS on working memory. However, little has been known about the segregative effects of tDCS on the sub-processes within working memory. Method Transcranial direct current stimulation, as one of the non-invasive brain stimulation techniques, is being widely used to modulate the cortical activation of local brain areas. This study modified a spatial n-back experiment with anodal and cathodal tDCS exertion on the right dorsolateral prefrontal cortex (DLPFC, aiming to investigate the effects of tDCS on the two sub-processes of working memory: manipulation (updating and maintenance. Meanwhile, considering the separability of tDCS effects, we further reconfirmed the causal relationship between the right DLPFC and the sub-processes of working memory with different tDCS conditions. Results The present study showed that cathodal tDCS on the right DLPFC selectively improved the performance of the modified 2-back task in the difficult condition, whereas anodal tDCS significantly reduced the performance of subjects and showed an speeding-up tendency of response time. More precisely, the results of discriminability index and criterion showed that only cathodal tDCS enhanced the performance of maintenance in the difficult condition. Neither of the two tDCS conditions affected the performance of manipulation (updating. Conclusion These findings provide evidence that cathodal tDCS of the right DLPFC selectively affects maintenance capacity. Besides, cathodal tDCS also serves as an interference suppressor to reduce the irrelevant interference, thereby indirectly improving the working memory capacity. Moreover, the right DLPFC is not the unique brain regions for working memory

  13. The basolateral amygdala modulates specific sensory memory representations in the cerebral cortex

    Chavez, Candice M.; McGaugh, James L.; Weinberger, Norman M.

    2008-01-01

    Stress hormones released by an experience can modulate memory strength via the basolateral amygdala, which in turn acts on sites of memory storage such as the cerebral cortex [McGaugh, J. L. (2004). The amygdala modulates the consolidation of memories of emotionally arousing experiences. Annual Review of Neuroscience, 27, 1–28]. Stimuli that acquire behavioral importance gain increased representation in the cortex. For example, learning shifts the tuning of neurons in the primary auditory cor...

  14. Cannabinoids and glucocorticoids modulate emotional memory after stress.

    Akirav, Irit

    2013-12-01

    Bidirectional and functional relationships between glucocorticoids and the endocannabinoid system have been demonstrated. Here, I review the interaction between the endocannabinoid and glucocorticoid/stress systems. Specifically, stress is known to produce rapid changes in endocannabinoid signaling in stress-responsive brain regions. In turn, the endocannabinoid system plays an important role in the downregulation and habituation of hypothalamic-pituitary-adrenocortical (HPA) axis activity in response to stress. Glucocorticoids also recruit the endocannabinoid system to exert rapid negative feedback control of the HPA axis during stress. It became increasingly clear, however, that cannabinoid CB1 receptors are also abundantly expressed in the basolateral amygdala (BLA) and other limbic regions where they modulate emotional arousal effects on memory. Enhancing cannabinoids signaling using exogenous CB1 receptor agonists prevent the effects of acute stress on emotional memory. I propose a model suggesting that the ameliorating effects of exogenously administered cannabinoids on emotional learning after acute stress are mediated by the decrease in the activity of the HPA axis via GABAergic mechanisms in the amygdala. Copyright © 2013 Elsevier Ltd. All rights reserved.

  15. Channel equalization techniques for non-volatile memristor memories

    Naous, Rawan

    2016-03-16

    Channel coding and information theoretic approaches have been utilized in conventional non-volatile memories to overcome their inherent design limitations of leakage, coupling and refresh rates. However, the continuous scaling and integration constraints set on the current devices directed the attention towards emerging memory technologies as suitable alternatives. Memristive devices are prominent candidates to replace the conventional electronics due to its non-volatility and small feature size. Nonetheless, memristor-based memories still encounter an accuracy limitation throughout the read operation addressed as the sneak path phenomenon. The readout data is corrupted with added distortion that increases significantly the bit error rate and jeopardizes the reliability of the read operation. A novel technique is applied to alleviate this distorting effect where the communication channel model is proposed for the memory array. Noise cancellation principles are applied with the aid of preset pilots to extract channel information and adjust the readout values accordingly. The proposed technique has the virtue of high speed, energy efficiency, and low complexity design while achieving high reliability and error-free decoding.

  16. Channel equalization techniques for non-volatile memristor memories

    Naous, Rawan; Zidan, Mohammed A.; Salem, Ahmed Sultan; Salama, Khaled N.

    2016-01-01

    Channel coding and information theoretic approaches have been utilized in conventional non-volatile memories to overcome their inherent design limitations of leakage, coupling and refresh rates. However, the continuous scaling and integration constraints set on the current devices directed the attention towards emerging memory technologies as suitable alternatives. Memristive devices are prominent candidates to replace the conventional electronics due to its non-volatility and small feature size. Nonetheless, memristor-based memories still encounter an accuracy limitation throughout the read operation addressed as the sneak path phenomenon. The readout data is corrupted with added distortion that increases significantly the bit error rate and jeopardizes the reliability of the read operation. A novel technique is applied to alleviate this distorting effect where the communication channel model is proposed for the memory array. Noise cancellation principles are applied with the aid of preset pilots to extract channel information and adjust the readout values accordingly. The proposed technique has the virtue of high speed, energy efficiency, and low complexity design while achieving high reliability and error-free decoding.

  17. Affirmative Action. Module Number 16. Work Experience Program Modules. Coordination Techniques Series.

    Shawhan, Carl; Morley, Ray

    This self-instructional module, the last in a series of 16 on techniques for coordinating work experience programs, deals with affirmative action. Addressed in the module are the following topics: the nature of affirmative action legislation and regulations, the role of the teacher-coordinator as a resource person for affirmative action…

  18. Stochastic temperature modulation: A new technique in temperature-modulated DSC

    Schawe, J.E.K.; Huetter, T.; Heitz, C.; Alig, I.; Lellinger, D.

    2006-01-01

    A new temperature-modulated differential scanning calorimetry (TMDSC) technique is introduced. The technique is based on stochastic temperature modulation and has been developed as a consequence of a generalized theory of a temperature-modulated DSC. The quasi-static heat capacity and the frequency-dependent complex heat capacity can be determined over a wide frequency range in one single measurement without further calibration. Furthermore, the reversing and non-reversing heat flows are determined directly from the measured data. Examples show the frequency dependence of the glass transition, the isothermal curing of thermosets and a solid-solid transition

  19. Characterization of the phase transformations in shape-memory alloys by modulated differential scanning calorimetry

    Wei, Z.G.; Sandstroem, R.

    1999-01-01

    Modulated differential scanning calorimetry (MDSC) is a recently developed calorimetric technique, which has demonstrated some significant advantages over the conventional differential scanning calorimetry (DSC). By separating the reversing quantity from the non-reversing component in the total thermal events, it provides some new information that can not be obtained from the conventional DSC. The technique has been applied to various polycrystalline and single crystalline shape-memory alloys, including Cu-Zn-Al, Cu-Al-Ni, Ti-Ni(Cu), Ni-Mn-Ga and Fe-Mn-Si, to characterize the martensitic transformations, bainitic transformation, chemical and magnetic ordering transitions, atomic reordering and other kinetic relaxation processes in the alloys. The preliminary results of the MDSC measurements are summarized and the interpretation of the MDSC results and some factors affecting the results are discussed. (orig.)

  20. Preliminary Studies Of A Phase Modulation Technique For Measuring Chromaticity

    Tan, C.-Y.

    2006-01-01

    The classical method for measuring chromaticity is to slowly modulate the RF frequency and then measure the betatron tune excursion. The technique that is discussed in this paper instead modulates the phase of the RF and then the chromaticity is obtained by phase demodulating the betatron tune. This technique requires knowledge of the betatron frequency in real time in order for the phase to be demodulated. Fortunately, the Tevatron has a tune tracker based on the phase locked loop principle which fits this requirement. A preliminary study with this technique has showed that it is a promising method for doing continuous chromaticity measurement and raises the possibility of doing successful chromaticity feedback with it

  1. Working memory distortions of duration perception are modulated by attentional tags.

    Pan, Yi; Hou, Xiu

    2016-03-01

    Recent research has shown that the contents of working memory can alter our perceptual experiences of visual matching stimuli. However, it is possible that different kinds of working memory representations may distort visual perception in different ways. In the present study, we associated working memory representations with different attentional tags and then examined their effects on perceived duration. The results showed that working memory representations prolonged apparent duration when they were tagged as a target and shortened perceived duration when they were tagged as a distractor. This is the first demonstration that attentional tags can modulate working memory effects on perceptual experience. We conclude that the influences of working memory on visual perception are determined not only by what information to be held in memory, but also by how the information is represented in memory. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Process, Voltage and Temperature Compensation Technique for Cascode Modulated PAs

    Sira, Daniel; Larsen, Torben

    2013-01-01

    , that represents a transistor level model (empirical model) of the cascode modulated PA, is utilized in a PA analog predistorter. The analog predistorter linearizes and compensates for PVT variation of the cascode modulated PA. The empirical model is placed in the negative feedback of an operational...... transconductance amplifier. The predistorted varying envelope signal is applied to the cascode gate of the PA. It is shown that the proposed PVT compensation technique significantly reduces the PVT spread of the PA linearity indicators and improves the PA linearity. Simulations were performed in a 0.13 μm CMOS...

  3. Sizing of SRAM Cell with Voltage Biasing Techniques for Reliability Enhancement of Memory and PUF Functions

    Chip-Hong Chang

    2016-08-01

    Full Text Available Static Random Access Memory (SRAM has recently been developed into a physical unclonable function (PUF for generating chip-unique signatures for hardware cryptography. The most compelling issue in designing a good SRAM-based PUF (SPUF is that while maximizing the mismatches between the transistors in the cross-coupled inverters improves the quality of the SPUF, this ironically also gives rise to increased memory read/write failures. For this reason, the memory cells of existing SPUFs cannot be reused as storage elements, which increases the overheads of cryptographic system where long signatures and high-density storage are both required. This paper presents a novel design methodology for dual-mode SRAM cell optimization. The design conflicts are resolved by using word-line voltage modulation, dynamic voltage scaling, negative bit-line and adaptive body bias techniques to compensate for reliability degradation due to transistor downsizing. The augmented circuit-level techniques expand the design space to achieve a good solution to fulfill several otherwise contradicting key design qualities for both modes of operation, as evinced by our statistical analysis and simulation results based on complementary metal–oxide–semiconductor (CMOS 45 nm bulk Predictive Technology Model.

  4. Memory Self-Efficacy Beliefs Modulate Brain Activity when Encoding Real-World Future Intentions

    Kalpouzos, Gr?goria; Eriksson, Johan

    2013-01-01

    Background: While the use of different cognitive strategies when encoding episodic memory information has been extensively investigated, modulation of brain activity by memory self-efficacy beliefs has not been studied yet. Methodology/Principal Findings: Sixteen young adults completed the prospective and retrospective metamemory questionnaire, providing individual subjective judgments of everyday memory function. The day after, using functional magnetic resonance imaging, the participants ha...

  5. Memory Consolidation within the Central Amygdala Is Not Necessary for Modulation of Cerebellar Learning

    Steinmetz, Adam B.; Ng, Ka H.; Freeman, John H.

    2017-01-01

    Amygdala lesions impair, but do not prevent, acquisition of cerebellum-dependent eyeblink conditioning suggesting that the amygdala modulates cerebellar learning. Two-factor theories of eyeblink conditioning posit that a fast-developing memory within the amygdala facilitates slower-developing memory within the cerebellum. The current study tested…

  6. Stress Response Recruits the Hippocampal Endocannabinoid System for the Modulation of Fear Memory

    Alvares, Lucas de Oliveira; Engelke, Douglas Senna; Diehl, Felipe; Scheffer-Teixeira, Robson; Haubrich, Josue; Cassini, Lindsey de Freitas; Molina, Victor Alejandro; Quillfeldt, Jorge Alberto

    2010-01-01

    The modulation of memory processes is one of the several functions of the endocannabinoid system (ECS) in the brain, with CB1 receptors highly expressed in areas such as the dorsal hippocampus. Experimental evidence suggested an important role of the ECS in aversively motivated memories. Similarly, glucocorticoids released in response to stress…

  7. Models, modules and abelian groups in memory of A.L.S.Corner

    Goldsmith, Brendan

    2008-01-01

    This is a memorial volume dedicated to A. L. S. Corner, previously Professor in Oxford, who published important results on algebra, especially on the connections of modules with endomorphism algebras. The volume contains refereed contributions which are related to the work of Corner.It contains also an unpublished extended paper of Corner himself. A memorial volume with important contributions related to algebra.

  8. Impairment in emotional modulation of attention and memory in schizophrenia.

    Walsh-Messinger, Julie; Ramirez, Paul Michael; Wong, Philip; Antonius, Daniel; Aujero, Nicole; McMahon, Kevin; Opler, Lewis A; Malaspina, Dolores

    2014-08-01

    Emotion plays a critical role in cognition and goal-directed behavior via complex interconnections between the emotional and motivational systems. It has been hypothesized that the impairment in goal-directed behavior widely noted in schizophrenia may result from defects in the interaction between the neural (ventral) emotional system and (rostral) cortical processes. The present study examined the impact of emotion on attention and memory in schizophrenia. Twenty-five individuals with schizophrenia related psychosis and 25 healthy control subjects were administered a computerized task in which they were asked to search for target images during a Rapid Serial Visual Presentation of pictures. Target stimuli were either positive or negative, or neutral images presented at either 200ms or 700ms lag. Additionally, a visual hedonic task was used to assess differences between the schizophrenia group and controls on ratings of valence and arousal from the picture stimuli. Compared to controls, individuals with schizophrenia detected fewer emotional images under both the 200ms and 700ms lag conditions. Multivariate analyses showed that the schizophrenia group also detected fewer positive images under the 700ms lag condition and fewer negative images under the 200ms lag condition. Individuals with schizophrenia reported higher pleasantness and unpleasantness ratings than controls in response to neutral stimuli, while controls reported higher arousal ratings for neutral and positive stimuli compared to the schizophrenia group. These results highlight dysfunction in the neural modulation of emotion, attention, and cortical processing in schizophrenia, adding to the growing but mixed body of literature on emotion processing in the disorder. Published by Elsevier B.V.

  9. Modulation/demodulation techniques for satellite communications. Part 1: Background

    Omura, J. K.; Simon, M. K.

    1981-01-01

    Basic characteristics of digital data transmission systems described include the physical communication links, the notion of bandwidth, FCC regulations, and performance measurements such as bit rates, bit error probabilities, throughputs, and delays. The error probability performance and spectral characteristics of various modulation/demodulation techniques commonly used or proposed for use in radio and satellite communication links are summarized. Forward error correction with block or convolutional codes is also discussed along with the important coding parameter, channel cutoff rate.

  10. Category Specific Knowledge Modulate Capacity Limitations of Visual Short-Term Memory

    Dall, Jonas Olsen; Watanabe, Katsumi; Sørensen, Thomas Alrik

    2016-01-01

    We explore whether expertise can modulate the capacity of visual short-term memory, as some seem to argue that training affects capacity of short-term memory [13] while others are not able to find this modulation [12]. We extend on a previous study [3] demonstrating expertise effects by investiga...... are in line with the theoretical interpretation that visual short-term memory reflects the sum of the reverberating feedback loops to representations in long-term memory.......We explore whether expertise can modulate the capacity of visual short-term memory, as some seem to argue that training affects capacity of short-term memory [13] while others are not able to find this modulation [12]. We extend on a previous study [3] demonstrating expertise effects......), and expert observers (Japanese university students). For both the picture and the letter condition we find no performance difference in memory capacity, however, in the critical hiragana condition we demonstrate a systematic difference relating expertise differences between the groups. These results...

  11. Architectural Techniques to Enable Reliable and Scalable Memory Systems

    Nair, Prashant J.

    2017-01-01

    High capacity and scalable memory systems play a vital role in enabling our desktops, smartphones, and pervasive technologies like Internet of Things (IoT). Unfortunately, memory systems are becoming increasingly prone to faults. This is because we rely on technology scaling to improve memory density, and at small feature sizes, memory cells tend to break easily. Today, memory reliability is seen as the key impediment towards using high-density devices, adopting new technologies, and even bui...

  12. Escaping Capture: Bilingualism Modulates Distraction from Working Memory

    Hernandez, Mireia; Costa, Albert; Humphreys, Glyn W.

    2012-01-01

    We ask whether bilingualism aids cognitive control over the inadvertent guidance of visual attention from working memory and from bottom-up cueing. We compare highly-proficient Catalan-Spanish bilinguals with Spanish monolinguals in three visual search conditions. In the working memory (WM) condition, attention was driven in a top-down fashion by…

  13. Frontal Neurons Modulate Memory Retrieval across Widely Varying Temporal Scales

    Zhang, Wen-Hua; Williams, Ziv M.

    2015-01-01

    Once a memory has formed, it is thought to undergo a gradual transition within the brain from short- to long-term storage. This putative process, however, also poses a unique problem to the memory system in that the same learned items must also be retrieved across broadly varying time scales. Here, we find that neurons in the ventrolateral…

  14. Content-specific working memory modulation of the attentional blink

    Akyürek, Elkan G.; Abedian-Amiri, Ali; Ostermeier, Sonja M.

    2011-01-01

    Three experiments were conducted to investigate the effects of working memory content on temporal attention in a rapid serial visual presentation attentional blink paradigm. It was shown that categorical similarity between working memory content and the target stimuli pertaining to the attentional

  15. CellSs: Scheduling Techniques to Better Exploit Memory Hierarchy

    Pieter Bellens

    2009-01-01

    Full Text Available Cell Superscalar's (CellSs main goal is to provide a simple, flexible and easy programming approach for the Cell Broadband Engine (Cell/B.E. that automatically exploits the inherent concurrency of the applications at a task level. The CellSs environment is based on a source-to-source compiler that translates annotated C or Fortran code and a runtime library tailored for the Cell/B.E. that takes care of the concurrent execution of the application. The first efforts for task scheduling in CellSs derived from very simple heuristics. This paper presents new scheduling techniques that have been developed for CellSs for the purpose of improving an application's performance. Additionally, the design of a new scheduling algorithm is detailed and the algorithm evaluated. The CellSs scheduler takes an extension of the memory hierarchy for Cell/B.E. into account, with a cache memory shared between the SPEs. All new scheduling practices have been evaluated showing better behavior of our system.

  16. Optical modulation techniques for analog signal processing and CMOS compatible electro-optic modulation

    Gill, Douglas M.; Rasras, Mahmoud; Tu, Kun-Yii; Chen, Young-Kai; White, Alice E.; Patel, Sanjay S.; Carothers, Daniel; Pomerene, Andrew; Kamocsai, Robert; Beattie, James; Kopa, Anthony; Apsel, Alyssa; Beals, Mark; Mitchel, Jurgen; Liu, Jifeng; Kimerling, Lionel C.

    2008-02-01

    Integrating electronic and photonic functions onto a single silicon-based chip using techniques compatible with mass-production CMOS electronics will enable new design paradigms for existing system architectures and open new opportunities for electro-optic applications with the potential to dramatically change the management, cost, footprint, weight, and power consumption of today's communication systems. While broadband analog system applications represent a smaller volume market than that for digital data transmission, there are significant deployments of analog electro-optic systems for commercial and military applications. Broadband linear modulation is a critical building block in optical analog signal processing and also could have significant applications in digital communication systems. Recently, broadband electro-optic modulators on a silicon platform have been demonstrated based on the plasma dispersion effect. The use of the plasma dispersion effect within a CMOS compatible waveguide creates new challenges and opportunities for analog signal processing since the index and propagation loss change within the waveguide during modulation. We will review the current status of silicon-based electrooptic modulators and also linearization techniques for optical modulation.

  17. Fault-tolerant NAND-flash memory module for next-generation scientific instruments

    Lange, Tobias; Michel, Holger; Fiethe, Björn; Michalik, Harald; Walter, Dietmar

    2015-10-01

    Remote sensing instruments on today's space missions deliver a high amount of data which is typically evaluated on ground. Especially for deep space missions the telemetry downlink is very limited which creates the need for the scientific evaluation and thereby a reduction of data volume already on-board the spacecraft. A demanding example is the Polarimetric and Helioseismic Imager (PHI) instrument on Solar Orbiter. To enable on-board offline processing for data reduction, the instrument has to be equipped with a high capacity memory module. The module is based on non-volatile NAND-Flash technology, which requires more advanced operation than volatile DRAM. Unlike classical mass memories, the module is integrated into the instrument and allows readback of data for processing. The architecture and safe operation of such kind of memory module is described in the following paper.

  18. Modulation Techniques for Biomedical Implanted Devices and Their Challenges

    Salina A. Samad

    2011-12-01

    Full Text Available Implanted medical devices are very important electronic devices because of their usefulness in monitoring and diagnosis, safety and comfort for patients. Since 1950s, remarkable efforts have been undertaken for the development of bio-medical implanted and wireless telemetry bio-devices. Issues such as design of suitable modulation methods, use of power and monitoring devices, transfer energy from external to internal parts with high efficiency and high data rates and low power consumption all play an important role in the development of implantable devices. This paper provides a comprehensive survey on various modulation and demodulation techniques such as amplitude shift keying (ASK, frequency shift keying (FSK and phase shift keying (PSK of the existing wireless implanted devices. The details of specifications, including carrier frequency, CMOS size, data rate, power consumption and supply, chip area and application of the various modulation schemes of the implanted devices are investigated and summarized in the tables along with the corresponding key references. Current challenges and problems of the typical modulation applications of these technologies are illustrated with a brief suggestions and discussion for the progress of implanted device research in the future. It is observed that the prime requisites for the good quality of the implanted devices and their reliability are the energy transformation, data rate, CMOS size, power consumption and operation frequency. This review will hopefully lead to increasing efforts towards the development of low powered, high efficient, high data rate and reliable implanted devices.

  19. Solar modulation of galactic cosmic rays: techniques and applications

    Perko, J.S.

    1984-01-01

    This thesis covers four topics in the theory of interplanetary cosmic-ray propagation: the first part involves the time-dependent, spherically-symmetric, solar modulation of galactic cosmic rays. A numerical technique was introduced for the solution of this problem. A model for the solar cycle variation in cosmic-ray intensity illustrated this method using enhanced particle scattering regions. The second section contains an attempt to explain recent observations which show that cosmic-ray electrons are returning to higher intensities, characteristic of solar minimum, faster than cosmic-ray protons of about the same energy, the reverse of the previous eleven-year cycle. The third section involves the solar modulation of galactic antiprotons. Using a steady-state, spherically-symmetric, numerical modulation code, a solution that reasonably fits the observed 1980 galactic proton spectrum at 1 AU implied that the modulation used for the data interpretation has been significantly underestimated. The final section contains a spherically-symmetric steady-state calculation of the effects of a strong termination shock in the heliosphere. In the end, high-energy particles cooling down in the upstream solar wind overwhelmed any accelerated low-energy particles

  20. The Role of Nitric Oxide in Memory is Modulated by Diurnal Time

    Stephanie L. Gage

    2014-04-01

    Full Text Available Nitric oxide (NO is thought to play an important neuromodulatory role in the olfactory system. This modulation has been suggested to be particularly important for olfactory learning and memory in the antennal lobe (the primary olfactory network in invertebrates. We are using the hawkmoth, Manduca sexta, to further investigate the role of NO in olfactory memory. Recent findings suggest that NO affects short-term memory traces and that NO concentration fluctuates with the light cycle. This gives rise to the hypothesis that NO may be involved in the connection between memory and circadian rhythms. In this study, we explore the role of diurnal time and NO in memory by altering the time of day when associative-olfactory conditioning is performed. We find a strong effect of NO on short-term memory, and two surprising effects of diurnal time. We find that (1 at certain time points, NO affects longer traces of memory in addition to short-term memory, and (2 when conditioning is performed close to the light cycle switches—both from light to dark and dark to light—NO does not significantly affect memory at all. These findings suggest an intriguing functional role for NO in olfactory conditioning that is modulated as a function of diurnal time.

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

    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.

  2. Glucose enhancement of memory is modulated by trait anxiety in healthy adolescent males.

    Smith, Michael A; Hii, Hilary L; Foster, Jonathan K; van Eekelen, J A M

    2011-01-01

    Glucose administration is associated with memory enhancement in healthy young individuals under conditions of divided attention at encoding. While the specific neurocognitive mechanisms underlying this 'glucose memory facilitation effect' are currently uncertain, it is thought that individual differences in glucoregulatory efficiency may alter an individual's sensitivity to the glucose memory facilitation effect. In the present study, we sought to investigate whether basal hypothalamic-pituitary-adrenal axis function (itself a modulator of glucoregulatory efficiency), baseline self-reported stress and trait anxiety influence the glucose memory facilitation effect. Adolescent males (age range = 14-17 years) were administered glucose and placebo prior to completing a verbal episodic memory task on two separate testing days in a counter-balanced, within-subjects design. Glucose ingestion improved verbal episodic memory performance when memory recall was tested (i) within an hour of glucose ingestion and encoding, and (ii) one week subsequent to glucose ingestion and encoding. Basal hypothalamic-pituitary-adrenal axis function did not appear to influence the glucose memory facilitation effect; however, glucose ingestion only improved memory in participants reporting relatively higher trait anxiety. These findings suggest that the glucose memory facilitation effect may be mediated by biological mechanisms associated with trait anxiety.

  3. Techniques for Reducing Consistency-Related Communication in Distributed Shared Memory System

    Zwaenepoel, W; Bennett, J.K.; Carter, J.B.

    1995-01-01

    Distributed shared memory 8DSM) is an abstraction of shared memory on a distributed memory machine. Hardware DSM systems support this abstraction at the architecture level; software DSM systems support the abstraction within the runtime system. One of the key problems in building an efficient software DSM system is to reduce the amount of communication needed to keep the distributed memories consistent. In this paper we present four techniques for doing so: 1) software release consistency; 2)...

  4. Electric-field-controlled interface dipole modulation for Si-based memory devices.

    Miyata, Noriyuki

    2018-05-31

    Various nonvolatile memory devices have been investigated to replace Si-based flash memories or emulate synaptic plasticity for next-generation neuromorphic computing. A crucial criterion to achieve low-cost high-density memory chips is material compatibility with conventional Si technologies. In this paper, we propose and demonstrate a new memory concept, interface dipole modulation (IDM) memory. IDM can be integrated as a Si field-effect transistor (FET) based memory device. The first demonstration of this concept employed a HfO 2 /Si MOS capacitor where the interface monolayer (ML) TiO 2 functions as a dipole modulator. However, this configuration is unsuitable for Si-FET-based devices due to its large interface state density (D it ). Consequently, we propose, a multi-stacked amorphous HfO 2 /1-ML TiO 2 /SiO 2 IDM structure to realize a low D it and a wide memory window. Herein we describe the quasi-static and pulse response characteristics of multi-stacked IDM MOS capacitors and demonstrate flash-type and analog memory operations of an IDM FET device.

  5. Intensity-modulated radiation therapy clinical evidence and techniques

    Nishimura, Yasumasa

    2015-01-01

    Successful clinical use of intensity-modulated radiation therapy (IMRT) represents a significant advance in radiation oncology. Because IMRT can deliver high-dose radiation to a target with a reduced dose to the surrounding organs, it can improve the local control rate and reduce toxicities associated with radiation therapy. Since IMRT began being used in the mid-1990s, a large volume of clinical evidence of the advantages of IMRT has been collected. However, treatment planning and quality assurance (QA) of IMRT are complicated and difficult for the clinician and the medical physicist. This book, by authors renowned for their expertise in their fields, provides cumulative clinical evidence and appropriate techniques for IMRT for the clinician and the physicist. Part I deals with the foundations and techniques, history, principles, QA, treatment planning, radiobiology and related aspects of IMRT. Part II covers clinical applications with several case studies, describing contouring and dose distribution with cl...

  6. Welding techniques development of CLAM steel for Test Blanket Module

    Li Chunjing [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui, 230031 (China); School of Nuclear Science and Technology, University of Science and Technology of China, Hefei, Anhui, 230027 (China)], E-mail: lcj@ipp.ac.cn; Huang Qunying; Wu Qingsheng; Liu Shaojun [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui, 230031 (China); School of Nuclear Science and Technology, University of Science and Technology of China, Hefei, Anhui, 230027 (China); Lei Yucheng [Jiangsu University, Zhenjiang, Jiangsu, 212013 (China); Muroga, Takeo; Nagasaka, Takuya [National Institute for Fusion Science, Toki, Jifu, 509-5292 (Japan); Zhang Jianxun [Xi' an Jiaotong University, Xi' an, Shanxi, 710049 (China); Li Jinglong [Northwestern Polytechnical University, Xi' an, Shanxi, 710072 (China)

    2009-06-15

    Fabrication techniques for Test Blanket Module (TBM) with CLAM are being under development. Effect of surface preparation on the HIP diffusion bonding joints was studied and good joints with Charpy impact absorbed energy close to that of base metal have been obtained. The mechanical properties test showed that effect of HIP process on the mechanical properties of base metal was little. Uniaxial diffusion bonding experiments were carried out to study the effect of temperature on microstructure and mechanical properties. And preliminary experiments on Electron Beam Welding (EBW), Tungsten Inert Gas (TIG) Welding and Laser Beam Welding (LBW) were performed to find proper welding techniques to assemble the TBM. In addition, the thermal processes assessed with a Gleeble thermal-mechanical machine were carried out as well to assist the fusion welding research.

  7. EPINEPHRINE AND GLUCOSE MODULATE TRAINING-RELATED CREB PHOSPHORYLATION IN OLD RATS: RELATIONSHIPS TO AGE-RELATED MEMORY IMPAIRMENTS

    Morris, Ken A.; Gold, Paul E.

    2012-01-01

    Epinephrine enhances memory in young adult rats, in part, by increasing blood glucose levels needed to modulate memory. In old rats, epinephrine is deficient at raising blood glucose levels and thus is only moderately effective at enhancing memory. In contrast, systemic glucose injections improve memory in old rats, with resulting memory performance equal to that of young rats. The diminished response of glucose to training in old rats may blunt downstream neurochemical and molecular mechanis...

  8. The hormonal Zeitgeber melatonin: Role as a circadian modulator in memory processing

    Oliver eRawashdeh

    2012-03-01

    Full Text Available The neuroendocrine substance melatonin is a hormone synthesized rhythmically by the pineal gland under the influence of the circadian system and alternating light/dark cycles. Melatonin has been shown to have broad applications, and consequently becoming a molecule of great controversy. Undoubtedly, however, melatonin plays an important role as a time cue for the endogenous circadian system. This review focuses on melatonin as a regulator in the circadian modulation of memory processing. Memory processes (acquisition, consolidation and retrieval are modulated by the circadian system. However, the mechanism by which the biological clock is rhythmically influencing cognitive processes remains unknown. We also discuss, how the circadian system by generating cycling melatonin levels can implant information about daytime into memory processing, depicted as day and nighttime differences in acquisition, memory consolidation and/or retrieval.

  9. Axially Modulated Clamped-Guided Arch Resonator for Memory and Logic Applications

    Hafiz, Md Abdullah Al; Tella, Sherif Adekunle; Alcheikh, Nouha; Fariborzi, Hossein; Younis, Mohammad I.

    2017-01-01

    We experimentally demonstrate memory and logic devices based on an axially modulated clamped-guided arch resonator. The device are electrostatically actuated and capacitively sensed, while the resonance frequency modulation is achieved through an axial electrostatic force from the guided side of the clamped-guided arch microbeam. We present two case studies: first, a dynamic memory based on the nonlinear frequency response of the resonator, and second, a reprogrammable two-input logic gate based on the linear frequency modulation of the resonator. These devices show energy cost per memory/logic operation in pJ, are fully compatible with CMOS fabrication processes, have the potential for on-chip system integration, and operate at room temperature.

  10. Axially Modulated Clamped-Guided Arch Resonator for Memory and Logic Applications

    Hafiz, Md Abdullah Al

    2017-11-03

    We experimentally demonstrate memory and logic devices based on an axially modulated clamped-guided arch resonator. The device are electrostatically actuated and capacitively sensed, while the resonance frequency modulation is achieved through an axial electrostatic force from the guided side of the clamped-guided arch microbeam. We present two case studies: first, a dynamic memory based on the nonlinear frequency response of the resonator, and second, a reprogrammable two-input logic gate based on the linear frequency modulation of the resonator. These devices show energy cost per memory/logic operation in pJ, are fully compatible with CMOS fabrication processes, have the potential for on-chip system integration, and operate at room temperature.

  11. Intensity Modulated Radiation Therapy. Development of the technique

    Rafailovici, L.; Alva, R.; Chiozza, J.; Donato, H.; Falomo, S.; Cardiello, C.; Furia, O.; Martinez, A.; Filomia, M.L.; Sansogne, R.; Arbiser, S.; Dosoretz, B.

    2008-01-01

    Full text: Introduction: Intensity Modulated Radiation Therapy (IMRT) is a result of advances in computer sciences that allowed the development of new technology related to planning and radiation therapy. IMRT was developed to homogenize the dose in the target volumes and decrease the dose in the surrounding healthy tissue. Using a software with high calculation capacity a simultaneous irradiation with different doses in a given volume is achieved. IMRT is based on internal planning. Material and methods: 628 patients were treated with IMRT in prostate lesions, head and neck, breast, thorax, abdomen and brain since August 2008. The software for IMRT is the XIO CMS and the accelerator used is a Varian Clinac 6 / 100. IMRT requires a first simulation, where immobilization systems are selected (mats, thermoplastic masks, among others) and the demarcation of the target structures, healthy tissue and dose prescription by a tattoo. Images of CT / MRI are merged when necessary. Once the system made the treatment optimization, this one is regulated by modulators. These are produced by numerical control machines from digital files produced by software. In a second modulation the planned irradiation is checked and tattoo is carried out according with this. We have a strict process of quality assurance to assess the viability of the plan before its implementation. We use the Map Check it possible to compare the dose on the central axis and the distribution in the whole plane regarding to that generated by the planning system. From 03/2008 the virtual simulation process was implemented integrating the described stages. Results and Conclusions: IMRT is a complex technique. The meticulous planning, implementation of process and quality control allows the use of this technique in a reliable and secure way. With IMRT we achieved a high level of dose conformation, less irradiation of healthy tissue, lower rates of complications and the dose escalation for some tumors. (authors) [es

  12. Non-Ocular Circadian Oscillators and Photoreceptors Modulate Long Term Memory Formation in Aplysia

    Lyons, Lisa C.; Rawashdeh, Oliver; Eskin, Arnold

    2006-01-01

    In Aplysia californica, memory formation for long-term sensitization (LTS) and for a more complex type of associative learning, learning that food is inedible (LFI), is modulated by a circadian clock. For both types of learning, formation of long-term memory occurs during the day and significantly less during the night. Aplysia eyes contain a well-characterized circadian oscillator that is strongly coupled to the locomotor activity rhythm. Thus, the authors hypothesized that the ocular circad...

  13. Comparative Study of Modulation Techniques for Two-Level Voltage Source Inverters

    Barry W. Williams

    2016-06-01

    Full Text Available A detailed comparative study of modulation techniques for single and three phase dc-ac inverters is presented.  Sinusoidal Pulse Width Modulation, Triplen Sinusoidal Pulse Width Modulation, Space Vector Modulation, Selective Harmonic Elimination and Wavelet Modulation are assessed and compared in terms of maximum fundamental output, harmonic performance, switching losses and operational mode.  The presented modulation techniques are applied to single and three phase voltage source inverters and are simulated using SIMULINK.  The simulation results clarify the inverter performance achieved using the different modulations techniques.

  14. Memory Device and Nanofabrication Techniques Using Electrically Configurable Materials

    Ascenso Simões, Bruno

    Development of novel nanofabrication techniques and single-walled carbon nanotubes field configurable transistor (SWCNT-FCT) memory devices using electrically configurable materials is presented. A novel lithographic technique, electric lithography (EL), that uses electric field for pattern generation has been demonstrated. It can be used for patterning of biomolecules on a polymer surface and patterning of resist as well. Using electrical resist composed of a polymer having Boc protected amine group and iodonium salt, Boc group on the surface of polymer was modified to free amine by applying an electric field. On the modified surface of the polymer, Streptavidin pattern was fabricated with a sub-micron scale. Also patterning of polymer resin composed of epoxy monomers and diaryl iodonium salt by EL has been demonstrated. Reaction mechanism for electric resist configuration is believed to be induced by an acid generation via electrochemical reduction in the resist. We show a novel field configurable transistor (FCT) based on single-walled carbon nanotube network field-effect transistors in which poly (ethylene glycol) crosslinked by electron-beam is incorporated into the gate. The device conductance can be configured to arbitrary states reversibly and repeatedly by applying external gate voltages. Raman spectroscopy revealed that evolution of the ratio of D- to G-band intensity in the SWCNTs of the FCT progressively increases as the device is configured to lower conductance states. Electron transport studies at low temperatures showed a strong temperature dependence of the resistance. Band gap widening of CNTs up to ˜ 4 eV has been observed by examining the differential conductance-gate voltage-bias voltage relationship. The switching mechanism of the FCT is attributed a structural transformation of CNTs via reversible hydrogenation and dehydrogenations induced by gate voltages, which tunes the CNT bandgap continuously and reversibly to non-volatile analog values

  15. Prefrontal cortical GABA modulation of spatial reference and working memory.

    Auger, Meagan L; Floresco, Stan B

    2014-10-31

    Dysfunction in prefrontal cortex (PFC) GABA transmission has been proposed to contribute to cognitive dysfunction in schizophrenia, yet how this system regulates different cognitive and mnemonic functions remains unclear. We assessed the effects of pharmacological reduction of GABAA signaling in the medial PFC of rats on spatial reference/working memory using different versions of the radial-arm maze task. We used a massed-trials procedure to probe how PFC GABA regulates susceptibility to proactive interference. Male rats were well-trained to retrieve food from the same 4 arms of an 8-arm maze, receiving 5 trials/day (1-2 min intervals). Infusions of the GABAA receptor antagonist bicuculline (12.5-50 ng) markedly increased working and reference memory errors and response latencies. Similar treatments also impaired short-term memory on an 8-baited arm task. These effects did not appear to be due to increased susceptibility to proactive interference. In contrast, PFC inactivation via infusion of GABA agonists baclofen/muscimol did not affect reference/working memory. In comparison to the pronounced effects on the 8-arm maze tasks, PFC GABAA antagonism only causes a slight and transient decrease in accuracy on a 2-arm spatial discrimination. These findings demonstrate that prefrontal GABA hypofunction severely disrupts spatial reference and short-term memory and that disinhibition of the PFC can, in some instances, perturb memory processes not normally dependent on the frontal lobes. Moreover, these impairments closely resemble those observed in schizophrenic patients, suggesting that perturbation in PFC GABA signaling may contribute to these types of cognitive deficits associated with the disorder. © The Author 2014. Published by Oxford University Press on behalf of CINP.

  16. Modulation of learning and memory by cytokines: signaling mechanisms and long term consequences.

    Donzis, Elissa J; Tronson, Natalie C

    2014-11-01

    This review describes the role of cytokines and their downstream signaling cascades on the modulation of learning and memory. Immune proteins are required for many key neural processes and dysregulation of these functions by systemic inflammation can result in impairments of memory that persist long after the resolution of inflammation. Recent research has demonstrated that manipulations of individual cytokines can modulate learning, memory, and synaptic plasticity. The many conflicting findings, however, have prevented a clear understanding of the precise role of cytokines in memory. Given the complexity of inflammatory signaling, understanding its modulatory role requires a shift in focus from single cytokines to a network of cytokine interactions and elucidation of the cytokine-dependent intracellular signaling cascades. Finally, we propose that whereas signal transduction and transcription may mediate short-term modulation of memory, long-lasting cellular and molecular mechanisms such as epigenetic modifications and altered neurogenesis may be required for the long lasting impact of inflammation on memory and cognition. Copyright © 2014 Elsevier Inc. All rights reserved.

  17. The Cholinergic System Modulates Memory and Hippocampal Plasticity via Its Interactions with Non-Neuronal Cells

    Sara V. Maurer

    2017-11-01

    Full Text Available Degeneration of central cholinergic neurons impairs memory, and enhancement of cholinergic synapses improves cognitive processes. Cholinergic signaling is also anti-inflammatory, and neuroinflammation is increasingly linked to adverse memory, especially in Alzheimer’s disease. Much of the evidence surrounding cholinergic impacts on the neuroimmune system focuses on the α7 nicotinic acetylcholine (ACh receptor, as stimulation of this receptor prevents many of the effects of immune activation. Microglia and astrocytes both express this receptor, so it is possible that some cholinergic effects may be via these non-neuronal cells. Though the presence of microglia is required for memory, overactivated microglia due to an immune challenge overproduce inflammatory cytokines, which is adverse for memory. Blocking these exaggerated effects, specifically by decreasing the release of tumor necrosis factor α (TNF-α, interleukin 1β (IL-1β, and interleukin 6 (IL-6, has been shown to prevent inflammation-induced memory impairment. While there is considerable evidence that cholinergic signaling improves memory, fewer studies have linked the “cholinergic anti-inflammatory pathway” to memory processes. This review will summarize the current understanding of the cholinergic anti-inflammatory pathway as it relates to memory and will argue that one mechanism by which the cholinergic system modulates hippocampal memory processes is its influence on neuroimmune function via the α7 nicotinic ACh receptor.

  18. Bayesian Inference on the Memory Parameter for Gamma-Modulated Regression Models

    Plinio Andrade

    2015-09-01

    Full Text Available In this work, we propose a Bayesian methodology to make inferences for the memory parameter and other characteristics under non-standard assumptions for a class of stochastic processes. This class generalizes the Gamma-modulated process, with trajectories that exhibit long memory behavior, as well as decreasing variability as time increases. Different values of the memory parameter influence the speed of this decrease, making this heteroscedastic model very flexible. Its properties are used to implement an approximate Bayesian computation and MCMC scheme to obtain posterior estimates. We test and validate our method through simulations and real data from the big earthquake that occurred in 2010 in Chile.

  19. Cerebellar transcranial direct current stimulation modulates verbal working memory.

    Boehringer, Andreas; Macher, Katja; Dukart, Juergen; Villringer, Arno; Pleger, Burkhard

    2013-07-01

    Neuroimaging studies show cerebellar activations in a wide range of cognitive tasks and patients with cerebellar lesions often present cognitive deficits suggesting a cerebellar role in higher-order cognition. We used cathodal transcranial direct current stimulation (tDCS), known to inhibit neuronal excitability, over the cerebellum to investigate if cathodal tDCS impairs verbal working memory, an important higher-order cognitive faculty. We tested verbal working memory as measured by forward and backward digit spans in 40 healthy young participants before and after applying cathodal tDCS (2 mA, stimulation duration 25 min) to the right cerebellum using a randomized, sham-controlled, double-blind, cross-over design. In addition, we tested the effect of cerebellar tDCS on word reading, finger tapping and a visually cued sensorimotor task. In line with lower digit spans in patients with cerebellar lesions, cerebellar tDCS reduced forward digit spans and blocked the practice dependent increase in backward digit spans. No effects of tDCS on word reading, finger tapping or the visually cued sensorimotor task were found. Our results support the view that the cerebellum contributes to verbal working memory as measured by forward and backward digit spans. Moreover, the induction of reversible "virtual cerebellar lesions" in healthy individuals by means of tDCS may improve our understanding of the mechanistic basis of verbal working memory deficits in patients with cerebellar lesions. Copyright © 2013 Elsevier Inc. All rights reserved.

  20. Vection Modulates Emotional Valence of Autobiographical Episodic Memories

    Seno, Takeharu; Kawabe, Takahiro; Ito, Hiroyuki; Sunaga, Shoji

    2013-01-01

    We examined whether illusory self-motion perception ("vection") induced by viewing upward and downward grating motion stimuli can alter the emotional valence of recollected autobiographical episodic memories. We found that participants recollected positive episodes more often while perceiving upward vection. However, when we tested a small moving…

  1. Interacting Brain Modules for Memory: An Adaptive Representations Architecture

    Gluck, Mark A

    2008-01-01

    ...) as a central system for creating optimal and adaptive stimulus representations, and then worked outwards from the hippocampal region to the brain systems that it modulates, including the cerebellum...

  2. Flavones from Erythrina falcata are modulators of fear memory.

    de Oliveira, Daniela Rodrigues; Zamberlam, Cláudia R; Gaiardo, Renan Barreta; Rêgo, Gizelda Maia; Cerutti, Janete M; Cavalheiro, Alberto J; Cerutti, Suzete M

    2014-08-05

    Flavonoids, which have been identified in a variety of plants, have been demonstrated to elicit beneficial effects on memory. Some studies have reported that flavonoids derived from Erythrina plants can provide such beneficial effects on memory. The aim of this study was to identify the flavonoids present in the stem bark crude extract of Erythrina falcata (CE) and to perform a bioactivity-guided study on conditioned fear memory. The secondary metabolites of CE were identified by high performance liquid chromatography combined with a diode array detector, electrospray ionization tandem mass spectrometry (HPLC-DAD-ESI/MSn) and nuclear magnetic resonance (NMR). The buthanolic fraction (BuF) was obtained by partitioning. Subfractions from BuF (BuF1 - BuF6) and fraction flavonoidic (FfA and FfB) were obtained by flash chromatography. The BuF3 and BuF4 fractions were used for the isolation of flavonoids, which was performed using HPLC-PAD. The isolated substances were quantified by HPLC-DAD and their structures were confirmed by nuclear magnetic resonance (NMR). The activities of CE and the subfractions were monitored using a one-trial, step-down inhibitory avoidance (IA) task to identify the effects of these substances on the acquisition and extinction of conditioned fear in rats. Six subclasses of flavonoids were identified for the first time in CE. According to our behavioral data, CE, BuF, BuF3 and BuF4, the flavonoidic fractions, vitexin, isovitexin and 6-C-glycoside-diosmetin improved the acquisition of fear memory. Rats treated with BuF, BuF3 and BuF4 were particularly resistant to extinction. Nevertheless, rats treated with FfA and FfB, vitexin, isovitexin and 6-C-glycoside-diosmetin exhibited gradual reduction in conditioned fear response during the extinction retest session, which was measured at 48 to 480 h after conditioning. Our results demonstrate that vitexin, isovitexin and diosmetin-6-C-glucoside and flavonoidic fractions resulted in a significant

  3. The role of verbal memory in regressions during reading is modulated by the target word's recency in memory.

    Guérard, Katherine; Saint-Aubin, Jean; Maltais, Marilyne; Lavoie, Hugo

    2014-10-01

    During reading, a number of eye movements are made backward, on words that have already been read. Recent evidence suggests that such eye movements, called regressions, are guided by memory. Several studies point to the role of spatial memory, but evidence for the role of verbal memory is more limited. In the present study, we examined the factors that modulate the role of verbal memory in regressions. Participants were required to make regressions on target words located in sentences displayed on one or two lines. Verbal interference was shown to affect regressions, but only when participants executed a regression on a word located in the first part of the sentence, irrespective of the number of lines on which the sentence was displayed. Experiments 2 and 3 showed that the effect of verbal interference on words located in the first part of the sentence disappeared when participants initiated the regression from the middle of the sentence. Our results suggest that verbal memory is recruited to guide regressions, but only for words read a longer time ago.

  4. An introduction to digital modulation and OFDM techniques

    Maddocks, M. C. D.

    This report differs from most BBC Research Department reports in that it does not contain details of a specific project undertaken at Kingswood Warren. While there has been a continuing development of aspects of digital modulation systems by BBC research engineers over many years, the purpose of this report is to be tutorial. That is, digital transmission techniques need to be explained in a general way if full advantage is to be obtained from other reports concerning digital broadcasting transmission systems. There are, however, references to other specialized publications if particular details are required. The text of this report is based on a paper which was prepared for an Institution of Electrical Engineers' vacation school on new broadcast standards and systems. It discusses, at a general level, the various issues and trade-offs that must be considered in the design of a digital modulation system for broadcast use. It particularly concentrates on giving a simple description of the use and benefits of OFDM systems. The particular issues can be applied to various future broadcast systems which are under development at the BBC and as part of collaborative work in international projects.

  5. High Dimensional Modulation and MIMO Techniques for Access Networks

    Binti Othman, Maisara

    Exploration of advanced modulation formats and multiplexing techniques for next generation optical access networks are of interest as promising solutions for delivering multiple services to end-users. This thesis addresses this from two different angles: high dimensionality carrierless...... the capacity per wavelength of the femto-cell network. Bit rate up to 1.59 Gbps with fiber-wireless transmission over 1 m air distance is demonstrated. The results presented in this thesis demonstrate the feasibility of high dimensionality CAP in increasing the number of dimensions and their potentially......) optical access network. 2 X 2 MIMO RoF employing orthogonal frequency division multiplexing (OFDM) with 5.6 GHz RoF signaling over all-vertical cavity surface emitting lasers (VCSEL) WDM passive optical networks (PONs). We have employed polarization division multiplexing (PDM) to further increase...

  6. Prefrontal Cortical GABA Modulation of Spatial Reference and Working Memory

    Auger, Meagan L.; Floresco, Stan B.

    2014-01-01

    Background: Dysfunction in prefrontal cortex (PFC) GABA transmission has been proposed to contribute to cognitive dysfunction in schizophrenia, yet how this system regulates different cognitive and mnemonic functions remains unclear. Methods: We assessed the effects of pharmacological reduction of GABAA signaling in the medial PFC of rats on spatial reference/working memory using different versions of the radial-arm maze task. We used a massed-trials procedure to probe how PFC GABA regulates ...

  7. How semantic category modulates preschool children's visual memory.

    Giganti, Fiorenza; Viggiano, Maria Pia

    2015-01-01

    The dynamic interplay between perception and memory has been explored in preschool children by presenting filtered stimuli regarding animals and artifacts. The identification of filtered images was markedly influenced by both prior exposure and the semantic nature of the stimuli. The identification of animals required less physical information than artifacts did. Our results corroborate the notion that the human attention system evolves to reliably develop definite category-specific selection criteria by which living entities are monitored in different ways.

  8. Acetylation-mediated suppression of transcription-independent memory: bidirectional modulation of memory by acetylation.

    Katja Merschbaecher

    Full Text Available Learning induced changes in protein acetylation, mediated by histone acetyl transferases (HATs, and the antagonistic histone deacetylases (HDACs play a critical role in memory formation. The status of histone acetylation affects the interaction between the transcription-complex and DNA and thus regulates transcription-dependent processes required for long-term memory (LTM. While the majority of studies report on the role of elevated acetylation in memory facilitation, we address the impact of both, increased and decreased acetylation on formation of appetitive olfactory memory in honeybees. We show that learning-induced changes in the acetylation of histone H3 at aminoacid-positions H3K9 and H3K18 exhibit distinct and different dynamics depending on the training strength. A strong training that induces LTM leads to an immediate increase in acetylation at H3K18 that stays elevated for hours. A weak training, not sufficient to trigger LTM, causes an initial increase in acetylation at H3K18, followed by a strong reduction in acetylation at H3K18 below the control group level. Acetylation at position H3K9 is not affected by associative conditioning, indicating specific learning-induced actions on the acetylation machinery. Elevating acetylation levels by blocking HDACs after conditioning leads to an improved memory. While memory after strong training is enhanced for at least 2 days, the enhancement after weak training is restricted to 1 day. Reducing acetylation levels by blocking HAT activity after strong training leads to a suppression of transcription-dependent LTM. The memory suppression is also observed in case of weak training, which does not require transcription processes. Thus, our findings demonstrate that acetylation-mediated processes act as bidirectional regulators of memory formation that facilitate or suppress memory independent of its transcription-requirement.

  9. Martin Mayman's early memories technique: bridging the gap between personality assessment and psychotherapy.

    Fowler, J C; Hilsenroth, M J; Handler, L

    2000-08-01

    In this article, we describe Martin Mayman's approach to early childhood memories as a projective technique, beginning with his scientific interest in learning theory, coupled with his interest in ego psychology and object relations theory. We describe Mayman's contributions to the use of the early memories technique to inform the psychotherapy process, tying assessment closely to psychotherapy and making assessment more useful in treatment. In this article, we describe a representative sample of research studies that demonstrate the reliability and validity of early memories, followed by case examples in which the early memories informed the therapy process, including issues of transference and countertransference.

  10. Effects of modulation techniques on the input current interharmonics of Adjustable Speed Drives

    Soltani, Hamid; Davari, Pooya; Zare, Firuz

    2018-01-01

    operation of the grid. This paper presents the effect of the symmetrical regularly sampled Space Vector Modulation (SVM) and Discontinuous Pulse Width Modulation-30olag (DPWM2) techniques, as the most popular modulation methods in the ASD applications, on the drive’s input current interharmonic magnitudes....... Further investigations are also devoted to the cases, where the Random Modulation (RM) technique is applied on the selected modulation strategies. The comparative results show that how different modulation techniques can influence the ASD’s input current interharmonics and consequently may...

  11. Consolidation differentially modulates schema effects on memory for items and associations.

    van Kesteren, Marlieke T R; Rijpkema, Mark; Ruiter, Dirk J; Fernández, Guillén

    2013-01-01

    Newly learned information that is congruent with a preexisting schema is often better remembered than information that is incongruent. This schema effect on memory has previously been associated to more efficient encoding and consolidation mechanisms. However, this effect is not always consistently supported in the literature, with differential schema effects reported for different types of memory, different retrieval cues, and the possibility of time-dependent effects related to consolidation processes. To examine these effects more directly, we tested participants on two different types of memory (item recognition and associative memory) for newly encoded visuo-tactile associations at different study-test intervals, thus probing memory retrieval accuracy for schema-congruent and schema-incongruent items and associations at different time points (t = 0, t = 20, and t = 48 hours) after encoding. Results show that the schema effect on visual item recognition only arises after consolidation, while the schema effect on associative memory is already apparent immediately after encoding, persisting, but getting smaller over time. These findings give further insight into different factors influencing the schema effect on memory, and can inform future schema experiments by illustrating the value of considering effects of memory type and consolidation on schema-modulated retrieval.

  12. Level of processing modulates the neural correlates of emotional memory formation

    Ritchey, Maureen; LaBar, Kevin S.; Cabeza, Roberto

    2010-01-01

    Emotion is known to influence multiple aspects of memory formation, including the initial encoding of the memory trace and its consolidation over time. However, the neural mechanisms whereby emotion impacts memory encoding remain largely unexplored. The present study employed a levels-of-processing manipulation to characterize the impact of emotion on encoding with and without the influence of elaborative processes. Participants viewed emotionally negative, neutral, and positive scenes under two conditions: a shallow condition focused on the perceptual features of the scenes and a deep condition that queried their semantic meaning. Recognition memory was tested 2 days later. Results showed that emotional memory enhancements were greatest in the shallow condition. FMRI analyses revealed that the right amygdala predicted subsequent emotional memory in the shallow more than deep condition, whereas the right ventrolateral prefrontal cortex demonstrated the reverse pattern. Furthermore, the association of these regions with the hippocampus was modulated by valence: the amygdala-hippocampal link was strongest for negative stimuli, whereas the prefrontal-hippocampal link was strongest for positive stimuli. Taken together, these results suggest two distinct activation patterns underlying emotional memory formation: an amygdala component that promotes memory during shallow encoding, especially for negative information, and a prefrontal component that provides extra benefits during deep encoding, especially for positive information. PMID:20350176

  13. Consolidation differentially modulates schema effects on memory for items and associations.

    Marlieke T R van Kesteren

    Full Text Available Newly learned information that is congruent with a preexisting schema is often better remembered than information that is incongruent. This schema effect on memory has previously been associated to more efficient encoding and consolidation mechanisms. However, this effect is not always consistently supported in the literature, with differential schema effects reported for different types of memory, different retrieval cues, and the possibility of time-dependent effects related to consolidation processes. To examine these effects more directly, we tested participants on two different types of memory (item recognition and associative memory for newly encoded visuo-tactile associations at different study-test intervals, thus probing memory retrieval accuracy for schema-congruent and schema-incongruent items and associations at different time points (t = 0, t = 20, and t = 48 hours after encoding. Results show that the schema effect on visual item recognition only arises after consolidation, while the schema effect on associative memory is already apparent immediately after encoding, persisting, but getting smaller over time. These findings give further insight into different factors influencing the schema effect on memory, and can inform future schema experiments by illustrating the value of considering effects of memory type and consolidation on schema-modulated retrieval.

  14. Level of processing modulates the neural correlates of emotional memory formation.

    Ritchey, Maureen; LaBar, Kevin S; Cabeza, Roberto

    2011-04-01

    Emotion is known to influence multiple aspects of memory formation, including the initial encoding of the memory trace and its consolidation over time. However, the neural mechanisms whereby emotion impacts memory encoding remain largely unexplored. The present study used a levels-of-processing manipulation to characterize the impact of emotion on encoding with and without the influence of elaborative processes. Participants viewed emotionally negative, neutral, and positive scenes under two conditions: a shallow condition focused on the perceptual features of the scenes and a deep condition that queried their semantic meaning. Recognition memory was tested 2 days later. Results showed that emotional memory enhancements were greatest in the shallow condition. fMRI analyses revealed that the right amygdala predicted subsequent emotional memory in the shallow more than deep condition, whereas the right ventrolateral PFC demonstrated the reverse pattern. Furthermore, the association of these regions with the hippocampus was modulated by valence: the amygdala-hippocampal link was strongest for negative stimuli, whereas the prefrontal-hippocampal link was strongest for positive stimuli. Taken together, these results suggest two distinct activation patterns underlying emotional memory formation: an amygdala component that promotes memory during shallow encoding, especially for negative information, and a prefrontal component that provides extra benefits during deep encoding, especially for positive information.

  15. Auditory Verbal Working Memory as a Predictor of Speech Perception in Modulated Maskers in Listeners With Normal Hearing

    Millman, Rebecca E.; Mattys, Sven L.

    2017-01-01

    Purpose: Background noise can interfere with our ability to understand speech. Working memory capacity (WMC) has been shown to contribute to the perception of speech in modulated noise maskers. WMC has been assessed with a variety of auditory and visual tests, often pertaining to different components of working memory. This study assessed the relationship between speech perception in modulated maskers and components of auditory verbal working memory (AVWM) over a range of signal-to-noise rati...

  16. Age differences in false memory: The importance of retrieval monitoring processes and their modulation by memory quality.

    Fandakova, Yana; Sander, Myriam C; Grandy, Thomas H; Cabeza, Roberto; Werkle-Bergner, Markus; Shing, Yee Lee

    2018-02-01

    Older adults are more likely than younger adults to falsely recall past episodes that occurred differently or not at all. We examined whether older adults' propensity for false associative memory is related to declines in postretrieval monitoring processes and their modulation with varying memory representations. Younger (N = 20) and older adults (N = 32) studied and relearned unrelated scene-word pairs, followed by a final cued recall that was used to distribute the pairs for an associative recognition test 24 hours later. This procedure allowed individualized formation of rearranged pairs that were made up of elements of pairs that were correctly recalled in the final cued recall ("high-quality" pairs), and of pairs that were not correctly recalled ("low-quality" pairs). Both age groups falsely recognized more low-quality than high-quality rearranged pairs, with a less pronounced reduction in false alarms to high-quality pairs in older adults. In younger adults, cingulo-opercular activity was enhanced for false alarms and for low-quality correct rejections, consistent with its role in postretrieval monitoring. Older adults did not show such modulated recruitment, suggesting deficits in their selective engagement of monitoring processes given variability in the fidelity of memory representations. There were no age differences in hippocampal activity, which was higher for high-quality than low-quality correct rejections in both age groups. These results demonstrate that the engagement of cingulo-opercular monitoring mechanisms varies with memory representation quality and contributes to age-related deficits in false associative memory. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

  17. Are training and transfer effects of working memory updating training modulated by achievement motivation?

    Zhao, X.; Xu, Y.; Fu, J.; Maes, J.H.R.

    2018-01-01

    Previous studies examining effects of working memory (WM) updating training revealed mixed results. One factor that might modulate training gains, and possibly also transfer of those gains to non-trained cognitive tasks, is achievement motivation. In the present Studies 1 and 2, students with either

  18. Memory Deficits Are Associated with Impaired Ability to Modulate Neuronal Excitability in Middle-Aged Mice

    Kaczorowski, Catherine C.; Disterhoft, John F.

    2009-01-01

    Normal aging disrupts hippocampal neuroplasticity and learning and memory. Aging deficits were exposed in a subset (30%) of middle-aged mice that performed below criterion on a hippocampal-dependent contextual fear conditioning task. Basal neuronal excitability was comparable in middle-aged and young mice, but learning-related modulation of the…

  19. Modulation of Hippocampal Theta Oscillations and Spatial Memory by Relaxin-3 Neurons of the Nucleus Incertus

    Ma, Sherie; Olucha-Bordonau, Francisco E.; Hossain, M. Akhter; Lin, Feng; Kuei, Chester; Liu, Changlu; Wade, John D.; Sutton, Steven W.; Nunez, Angel; Gundlach, Andrew L.

    2009-01-01

    Hippocampal theta rhythm is thought to underlie learning and memory, and it is well established that "pacemaker" neurons in medial septum (MS) modulate theta activity. Recent studies in the rat demonstrated that brainstem-generated theta rhythm occurs through a multisynaptic pathway via the nucleus incertus (NI), which is the primary source of the…

  20. Role of the hippocampus on learning and memory functioning and pain modulation

    Haimei Wang

    2008-01-01

    The hippocampus, an important part of the limbic system, is considered to be an important region of the brain for learning and memory functioning. Recent studies have demonstrated that synaptic plasticity is thought to be the basis of learning and memory functioning. A series of studies report that similar synaptic plasticity also exists in the spinal cord in the conduction pathway of pain sensation, which may contribute to hyperalgesia, abnormal pain, and analgesia. The synaptic plasticity of learning and memory functioning and that of the pain conduction pathway have similar mechanisms, which are related to the N-methyl-D-aspartic acid receptor. The hippocampus also has a role in pain modulation. As pain signals can reach the hippocampus, the precise correlation between synaptic plasticity of the pain pathway and that of learning and memory functioning deserves further investigation. The role of the hippocampus in processing pain information requires to be identified.

  1. Sleep modulates the neural substrates of both spatial and contextual memory consolidation.

    Géraldine Rauchs

    -training sleep modulates the neural substrates of the consolidation of both the spatial and contextual memories acquired during virtual navigation.

  2. Scaling Techniques for Massive Scale-Free Graphs in Distributed (External) Memory

    Pearce, Roger; Gokhale, Maya; Amato, Nancy M.

    2013-01-01

    We present techniques to process large scale-free graphs in distributed memory. Our aim is to scale to trillions of edges, and our research is targeted at leadership class supercomputers and clusters with local non-volatile memory, e.g., NAND Flash

  3. Performance improvement of charge trap flash memory by using a composition-modulated high-k trapping layer

    Tang Zhen-Jie; Li Rong; Yin Jiang

    2013-01-01

    A composition-modulated (HfO 2 ) x (Al 2 O3) 1−x charge trapping layer is proposed for charge trap flash memory by controlling the Al atom content to form a peak and valley shaped band gap. It is found that the memory device using the composition-modulated (HfO 2 ) x (Al 2 O 3 ) 1−x as the charge trapping layer exhibits a larger memory window of 11.5 V, improves data retention even at high temperature, and enhances the program/erase speed. Improvements of the memory characteristics are attributed to the special band-gap structure resulting from the composition-modulated trapping layer. Therefore, the composition-modulated charge trapping layer may be useful in future nonvolatile flash memory device application. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  4. Reward-dependent modulation of working memory in lateral prefrontal cortex.

    Kennerley, Steven W; Wallis, Jonathan D

    2009-03-11

    Although research implicates lateral prefrontal cortex (PFC) in executive control and goal-directed behavior, it remains unclear how goals influence executive processes. One possibility is that goal-relevant information, such as expected rewards, could modulate the representation of information relating to executive control, thereby ensuring the efficient allocation of cognitive resources. To investigate this, we examined how reward modulated spatial working memory. Past studies investigating spatial working memory have focused on dorsolateral PFC, but this area only weakly connects with areas processing reward. Ventrolateral PFC has better connections in this regard. Thus, we contrasted the functional properties of single neurons in ventrolateral and dorsolateral PFC as two subjects performed a task that required them to hold spatial information in working memory under different expectancies of reward for correct performance. We balanced the order of presentation of spatial and reward information so we could assess the neuronal encoding of the two pieces of information independently and conjointly. Neurons in ventrolateral PFC encoded both spatial and reward information earlier, stronger and in a more sustained manner than neurons in dorsolateral PFC. Within ventrolateral PFC, spatial selectivity was more prevalent on the inferior convexity than within the principal sulcus. Finally, when reward increased spatial selectivity, behavioral performance improved, whereas when reward decreased spatial selectivity, behavioral performance deteriorated. These results suggest that ventrolateral PFC may be a locus whereby information about expected rewards can modulate information in working memory. The pattern of results is consistent with a role for ventrolateral PFC in attentional control.

  5. Attention modulates maintenance of representations in visual short-term memory.

    Kuo, Bo-Cheng; Stokes, Mark G; Nobre, Anna Christina

    2012-01-01

    Recent studies have shown that selective attention is of considerable importance for encoding task-relevant items into visual short-term memory (VSTM) according to our behavioral goals. However, it is not known whether top-down attentional biases can continue to operate during the maintenance period of VSTM. We used ERPs to investigate this question across two experiments. Specifically, we tested whether orienting attention to a given spatial location within a VSTM representation resulted in modulation of the contralateral delay activity (CDA), a lateralized ERP marker of VSTM maintenance generated when participants selectively encode memory items from one hemifield. In both experiments, retrospective cues during the maintenance period could predict a specific item (spatial retrocue) or multiple items (neutral retrocue) that would be probed at the end of the memory delay. Our results revealed that VSTM performance is significantly improved by orienting attention to the location of a task-relevant item. The behavioral benefit was accompanied by modulation of neural activity involved in VSTM maintenance. Spatial retrocues reduced the magnitude of the CDA, consistent with a reduction in memory load. Our results provide direct evidence that top-down control modulates neural activity associated with maintenance in VSTM, biasing competition in favor of the task-relevant information.

  6. INDIVIDUALIZED THEORY OF MIND (iToM: WHEN MEMORY MODULATES EMPATHY

    Elisa eCiaramelli

    2013-02-01

    Full Text Available Functional neuroimaging studies have noted that brain regions supporting theory of mind (ToM overlap remarkably with those underlying episodic memory, suggesting a link between the two processes. The present study shows that memory for others’ past experiences modulates significantly our appraisal of, and reaction to, what is happening to them currently. Participants read the life story of two characters; one had experienced a long series of love-related failures, the other a long series of work-related failures. In a later faux pas recognition task, participants reported more empathy for the character unlucky in love in love-related faux pas scenarios, and for the character unlucky at work in work-related faux pas scenarios. The memory-based modulation of empathy correlated with the number of details remembered from the characters’ life story. These results suggest that individuals use memory for other people’s past experiences to simulate how they feel in similar situations they are currently facing. The integration of ToM and memory processes allows adjusting mental state inferences to fit unique social targets, constructing an individualized ToM (iToM.

  7. Memory Compression Techniques for Network Address Management in MPI

    Guo, Yanfei; Archer, Charles J.; Blocksome, Michael; Parker, Scott; Bland, Wesley; Raffenetti, Ken; Balaji, Pavan

    2017-05-29

    MPI allows applications to treat processes as a logical collection of integer ranks for each MPI communicator, while internally translating these logical ranks into actual network addresses. In current MPI implementations the management and lookup of such network addresses use memory sizes that are proportional to the number of processes in each communicator. In this paper, we propose a new mechanism, called AV-Rankmap, for managing such translation. AV-Rankmap takes advantage of logical patterns in rank-address mapping that most applications naturally tend to have, and it exploits the fact that some parts of network address structures are naturally more performance critical than others. It uses this information to compress the memory used for network address management. We demonstrate that AV-Rankmap can achieve performance similar to or better than that of other MPI implementations while using significantly less memory.

  8. Increasing the bit rate in OCDMA systems using pulse position modulation techniques.

    Arbab, Vahid R; Saghari, Poorya; Haghi, Mahta; Ebrahimi, Paniz; Willner, Alan E

    2007-09-17

    We have experimentally demonstrated two novel pulse position modulation techniques, namely Double Pulse Position Modulation (2-PPM) and Differential Pulse Position Modulation (DPPM) in Time-Wavelength OCDMA systems that will operate at a higher bit rate compared to traditional OOK-OCDMA systems with the same bandwidth. With 2-PPM technique, the number of active users will be more than DPPM while their bit rate is almost the same. Both techniques provide variable quality of service in OCDMA networks.

  9. Sexual behavior modulates contextual fear memory through dopamine D1/D5 receptors.

    Bai, Hua-Yi; Cao, Jun; Liu, Na; Xu, Lin; Luo, Jian-Hong

    2009-03-01

    Traumatic events always lead to aversive emotional memory, i.e., fear memory. In contrast, positive events in daily life such as sex experiences seem to reduce aversive memory after aversive events. Thus, we hypothesized that post-traumatic pleasurable experiences, especially instinctive behaviors such as sex, might modulate traumatic memory through a memory competition mechanism. Here, we first report that male rats persistently expressed much lower fear responses when exposed to females, but not when exposed to males, for 24 h immediately after contextual fear conditioning. Remarkably, this effect of sexual behavior was blocked by either systemic or intrahippocampal injection of the dopamine D1/D5 receptor antagonist R(+)-7-chloro-8-hydroxy-3-methyl-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine hydrochloride (SCH23390) and was mimicked by systemic but not intrahippocampal injection of the D1/D5 receptor agonist R(+)-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine-7,8-diol hydrochloride (SKF39393). Furthermore, as a candidate mechanism underlying contextual fear memory, the impaired induction of hippocampal long-term potentiation (LTP) elicited by conditioned fear was rescued in male rats immediately exposed to female but not male rats for 24 h. Systemic injection of the dopamine D1/D5 receptor antagonist SCH23390 or agonist SKF38393 prevented or mimicked the effect of sexual behavior on the impaired induction of hippocampal LTP. Thus, our finding suggests that dopaminergic functions may, at least partially, govern competition between contextual fear and enjoyable memories through the modulation of hippocampal LTP.

  10. Heterodyne technique for measuring the amplitude and phase transfer functions of an optical modulator

    Romstad, Francis Pascal; Birkedal, Dan; Mørk, Jesper

    2002-01-01

    In this letter, we propose a technique based on heterodyne detection for accurately and simultaneously measuring the amplitude and phase transfer functions of an optical modulator. The technique is used to characterize an InGaAsp multiple quantum-well electroabsorption modulator. From the measure...... the measurements we derive the small-signal alpha-parameter and the time-dependent chirp for different operation conditions.......In this letter, we propose a technique based on heterodyne detection for accurately and simultaneously measuring the amplitude and phase transfer functions of an optical modulator. The technique is used to characterize an InGaAsp multiple quantum-well electroabsorption modulator. From...

  11. Memory load modulates graded changes in distracter filtering

    Andria eShimi

    2015-01-01

    Full Text Available Our ability to maintain small amounts of information in mind is critical for successful performance on a wide range of tasks. However, it remains unclear exactly how this maintenance is achieved. One possibility is that it is brought about using mechanisms that overlap with those used for attentional control. That is, the same mechanisms that we use to regulate and optimise our sensory processing may be recruited when we maintain information in visual short-term memory (VSTM. We aimed to test this hypothesis by exploring how distracter filtering is modified by concurrent VSTM load. We presented participants with sequences of target items, the order and location of which had to be maintained in VSTM. We also presented distracter items alongside the targets, and these distracters were graded such that they could be either very similar or dissimilar to the targets. We analysed scalp potentials using a novel multiple regression approach, which enabled us to explore the neural mechanisms by which the participants accommodated these variable distracters on a trial-to-trial basis. Critically, the effect of distracter filtering interacted with VSTM load; the same graded changes in perceptual similarity exerted effects of a different magnitude depending upon how many items participants were already maintaining in VSTM. These data provide compelling evidence that maintaining information in VSTM recruits an overlapping set of attentional control mechanisms that are otherwise used for distracter filtering.

  12. Memory Forensics: Review of Acquisition and Analysis Techniques

    2013-11-01

    Management Overview Processes running on modern multitasking operating systems operate on an abstraction of RAM, called virtual memory [7]. In these systems...information such as user names, email addresses and passwords [7]. Analysts also use tools such as WinHex to identify headers or other suspicious data within

  13. The Visual Memory-Based Memorization Techniques in Piano Education

    Yucetoker, Izzet

    2016-01-01

    Problem Statement: Johann Sebastian Bach is one of the leading composers of the baroque period. In addition to his huge contributions in the artistic dimension, he also served greatly in the field of education. This study has been done for determining the impact of visual memory-based memorization practices in the piano education on the visual…

  14. Oracle database 12c release 2 in-memory tips and techniques for maximum performance

    Banerjee, Joyjeet

    2017-01-01

    This Oracle Press guide shows, step-by-step, how to optimize database performance and cut transaction processing time using Oracle Database 12c Release 2 In-Memory. Oracle Database 12c Release 2 In-Memory: Tips and Techniques for Maximum Performance features hands-on instructions, best practices, and expert tips from an Oracle enterprise architect. You will learn how to deploy the software, use In-Memory Advisor, build queries, and interoperate with Oracle RAC and Multitenant. A complete chapter of case studies illustrates real-world applications. • Configure Oracle Database 12c and construct In-Memory enabled databases • Edit and control In-Memory options from the graphical interface • Implement In-Memory with Oracle Real Application Clusters • Use the In-Memory Advisor to determine what objects to keep In-Memory • Optimize In-Memory queries using groups, expressions, and aggregations • Maximize performance using Oracle Exadata Database Machine and In-Memory option • Use Swingbench to create d...

  15. Positive modulation of a neutral declarative memory by a threatening social event.

    Fernández, Rodrigo S; Bavassi, Luz; Campos, Jorge; Allegri, Ricardo F; Molina, Victor A; Forcato, Cecilia; Pedreira, María E

    2015-12-01

    Memories can be altered by negative or arousing experiences due to the activation of the stress-responsive sympatho-adrenal-medullary axis (SYM). Here, we used a neutral declarative memory that was acquired during multi-trial training to determine the effect of a threatening event on memory without emotional valence. To this end, participants received a new threatening social protocol before learning pairs of meaningless syllables and were tested either 15 min, 2 days or 8 days after acquisition. We first demonstrated that this threatening social situation activates not only the SYM axis (Experiment 1) and the hypothalamus-pituitary-adrenal axis (HPA; Experiment 2), but also, it improves the acquisition or early consolidation of the syllable pairs (Experiment 3). This improvement is not a transient effect; it can be observed after the memory is consolidated. Furthermore, this modulation increases the persistence of memory (Experiment 4). Thus, it is possible to affect memories with specific events that contain unrelated content and a different valence. Copyright © 2015 Elsevier Inc. All rights reserved.

  16. Stress-related cortisol responsivity modulates prospective memory.

    Glienke, K; Piefke, M

    2017-12-01

    It is known that there is inter-individual variation in behavioural and physiological stress reactions to the same stressor. The present study aimed to examine the impact of cortisol responsivity on performance in a complex real life-like prospective memory (PM) paradigm by a re-analysis of data published previously, with a focus on the taxonomy of cognitive dimensions of PM. Twenty-one male subjects were stressed with the Socially Evaluated Cold Pressor Test (SECPT) before the planning of intentions. Another group of 20 males underwent a control procedure. Salivary cortisol was measured to assess the intensity of the biological stress response. Additionally, participants rated the subjective experience of stress on a 5-point rating scale. Stressed participants were post-hoc differentiated in high (n = 11) and low cortisol responders (n = 10). Cortisol niveau differed significantly between the two groups, whereas subjective stress ratings did not. PM performance of low cortisol responders was stable across time and the PM performance of controls declined. High cortisol responders showed a nominally weaker PM retrieval across the early trails and significantly improved only on the last trial. The data demonstrate for the first time that participants with a low cortisol responsivity may benefit from stress exposure before the planning phase of PM. PM performance of high cortisol responders shows a more inconsistent pattern, which may be interpreted in the sense of a recency effect in PM retrieval. Alternatively, high cortisol responses may have a deteriorating effect on PM retrieval, which disappeared on the last trials of the task as a result of the decrease of cortisol levels across time. Importantly, the data also demonstrate that the intensity of cortisol responses does not necessarily correspond to the intensity of the mental experience of stress. © 2017 British Society for Neuroendocrinology.

  17. Nuclear Technology. Course 26: Nondestructive Examination (NDE) Techniques I. Module 26-3, Hydrostatic Tests.

    Pelton, Rick; Espy, John

    This third in a series of seven modules for a course titled Nondestructive Examination (NDE) Techniques I describes the principles and practices associated with hydrostatic testing. The module follows a typical format that includes the following sections: (1) introduction, (2) module prerequisites, (3) objectives, (4) notes to instructor/student,…

  18. Specification and development of the sharing memory data management module for a nuclear processes simulator

    Telesforo R, D.

    2003-01-01

    Actually it is developed in the Engineering Faculty of UNAM a simulator of nuclear processes with research and teaching purposes. It consists of diverse modules, included the one that is described in the present work that is the shared memory module. It uses the IPC mechanisms of the UNIX System V operative system, and it was codified with C language. To model the diverse components of the simulator the RELAP code is used. The function of the module is to generate locations of shared memory for to deposit in these the necessary variables for the interaction among the diverse ones processes of the simulator. In its it will be able read and to write the information that generate the running of the simulation program, besides being able to interact with the internal variables of the code in execution time. The graphic unfolding (mimic, pictorials, tendency graphics, virtual instrumentation, etc.) they also obtain information of the shared memory. In turn, actions of the user in interactive unfolding, they modify the segments of shared memory, and the information is sent to the RELAP code to modify the simulation course. The program has two beginning modes: automatic and manual. In automatic mode taking an enter file of RELAP (indta) and it joins in shared memory, the control variables that in this appear. In manual mode the user joins, he reads and he writes the wanted control variables, whenever they exist in the enter file (indta). This is a dynamic mode of interacting with the simulator in a direct way and of even altering the values as when its don't exist in the board elements associated to the variables. (Author)

  19. How visual short-term memory maintenance modulates subsequent visual aftereffects.

    Saad, Elyana; Silvanto, Juha

    2013-05-01

    Prolonged viewing of a visual stimulus can result in sensory adaptation, giving rise to perceptual phenomena such as the tilt aftereffect (TAE). However, it is not known if short-term memory maintenance induces such effects. We examined how visual short-term memory (VSTM) maintenance modulates the strength of the TAE induced by subsequent visual adaptation. We reasoned that if VSTM maintenance induces aftereffects on subsequent encoding of visual information, then it should either enhance or reduce the TAE induced by a subsequent visual adapter, depending on the congruency of the memory cue and the adapter. Our results were consistent with this hypothesis and thus indicate that the effects of VSTM maintenance can outlast the maintenance period.

  20. NeuroD Modulates Opioid Agonist-Selective Regulation of Adult Neurogenesis and Contextual Memory Extinction

    Zheng, Hui; Zhang, Yue; Li, Wen; Loh, Horace H; Law, Ping-Yee

    2013-01-01

    Addictive drugs, including opioids, modulate adult neurogenesis. In order to delineate the probable implications of neurogenesis on contextual memory associated with addiction, we investigated opioid agonist-selective regulation of neurogenic differentiation 1 (NeuroD) activities under the conditioned place preference (CPP) paradigm. Training mice with equivalent doses of morphine and fentanyl produced different CPP extinction rates without measurable differences in the CPP acquisition rate o...

  1. Dopamine modulates memory consolidation of discrimination learning in the auditory cortex.

    Schicknick, Horst; Reichenbach, Nicole; Smalla, Karl-Heinz; Scheich, Henning; Gundelfinger, Eckart D; Tischmeyer, Wolfgang

    2012-03-01

    In Mongolian gerbils, the auditory cortex is critical for discriminating rising vs. falling frequency-modulated tones. Based on our previous studies, we hypothesized that dopaminergic inputs to the auditory cortex during and shortly after acquisition of the discrimination strategy control long-term memory formation. To test this hypothesis, we studied frequency-modulated tone discrimination learning of gerbils in a shuttle box GO/NO-GO procedure following differential treatments. (i) Pre-exposure of gerbils to the frequency-modulated tones at 1 day before the first discrimination training session severely impaired the accuracy of the discrimination acquired in that session during the initial trials of a second training session, performed 1 day later. (ii) Local injection of the D1/D5 dopamine receptor antagonist SCH-23390 into the auditory cortex after task acquisition caused a discrimination deficit of similar extent and time course as with pre-exposure. This effect was dependent on the dose and time point of injection. (iii) Injection of the D1/D5 dopamine receptor agonist SKF-38393 into the auditory cortex after retraining caused a further discrimination improvement at the beginning of subsequent sessions. All three treatments, which supposedly interfered with dopamine signalling during conditioning and/or retraining, had a substantial impact on the dynamics of the discrimination performance particularly at the beginning of subsequent training sessions. These findings suggest that auditory-cortical dopamine activity after acquisition of a discrimination of complex sounds and after retrieval of weak frequency-modulated tone discrimination memory further improves memory consolidation, i.e. the correct association of two sounds with their respective GO/NO-GO meaning, in support of future memory recall. © 2012 The Authors. European Journal of Neuroscience © 2012 Federation of European Neuroscience Societies and Blackwell Publishing Ltd.

  2. A New Contention Management Technique for Obstruction Free Transactional Memory

    Ghosh, Ammlan; Sahin, Anubhab; Silsarma, Anirban; Chaki, Rituparna

    2014-01-01

    Part 2: Algorithms; International audience; Transactional Memory, one of the most viable alternatives to lock based concurrent systems, was explored by the researchers for practically implementing parallel processing. The goal was that threads will run parallel and improve system performance, but the effect of their execution will be linear. In STM, the non-blocking synchronization can be implemented by Wait-Freedom, Lock-Freedom or Obstruction-Freedom philosophy. Though Obstruction Free Tran...

  3. Anticipation of electric shocks modulates low beta power and event-related fields during memory encoding.

    Bauch, Eva M; Bunzeck, Nico

    2015-09-01

    In humans, the temporal and oscillatory dynamics of pain anticipation and its effects on long-term memory are largely unknown. Here, we investigated this open question by using a previously established behavioral paradigm in combination with magnetoencephalography (MEG). Healthy human subjects encoded a series of scene images, which was combined with cues predicting an aversive electric shock with different probabilities (0.2, 0.5 or 0.8). After encoding, memory for the studied images was tested using a remember/know recognition task. Behaviorally, pain anticipation did not modulate recollection-based recognition memory per se, but interacted with the perceived unpleasantness of the electric shock [visual analogue scale rating from 1 (not unpleasant) to 10 (highly unpleasant)]. More precisely, the relationship between pain anticipation and recollection followed an inverted u-shaped function the more unpleasant the shocks were rated by a subject. At the physiological level, this quadratic effect was mimicked in the event-related magnetic fields associated with successful memory formation ('DM-effect') ∼450ms after image onset at left frontal sensors. Importantly, across all subjects, shock anticipation modulated oscillatory power in the low beta frequency range (13-20Hz) in a linear fashion at left temporal sensors. Taken together, our findings indicate that beta oscillations provide a generic mechanism underlying pain anticipation; the effect on subsequent long-term memory, on the other hand, is much more variable and depends on the level of individual pain perception. As such, our findings give new and important insights into how aversive motivational states can drive memory formation. Copyright © 2015 Elsevier Inc. All rights reserved.

  4. Communicative Signals Promote Object Recognition Memory and Modulate the Right Posterior STS.

    Redcay, Elizabeth; Ludlum, Ruth S; Velnoskey, Kayla R; Kanwal, Simren

    2016-01-01

    Detection of communicative signals is thought to facilitate knowledge acquisition early in life, but less is known about the role these signals play in adult learning or about the brain systems supporting sensitivity to communicative intent. The current study examined how ostensive gaze cues and communicative actions affect adult recognition memory and modulate neural activity as measured by fMRI. For both the behavioral and fMRI experiments, participants viewed a series of videos of an actress acting on one of two objects in front of her. Communicative context in the videos was manipulated in a 2 × 2 design in which the actress either had direct gaze (Gaze) or wore a visor (NoGaze) and either pointed at (Point) or reached for (Reach) one of the objects (target) in front of her. Participants then completed a recognition memory task with old (target and nontarget) objects and novel objects. Recognition memory for target objects in the Gaze conditions was greater than NoGaze, but no effects of gesture type were seen. Similarly, the fMRI video-viewing task revealed a significant effect of Gaze within right posterior STS (pSTS), but no significant effects of Gesture. Furthermore, pSTS sensitivity to Gaze conditions was related to greater memory for objects viewed in Gaze, as compared with NoGaze, conditions. Taken together, these results demonstrate that the ostensive, communicative signal of direct gaze preceding an object-directed action enhances recognition memory for attended items and modulates the pSTS response to object-directed actions. Thus, establishment of a communicative context through ostensive signals remains an important component of learning and memory into adulthood, and the pSTS may play a role in facilitating this type of social learning.

  5. Olfactory or auditory stimulation and their hedonic valúes differentially modulate visual working memory

    ANA M DONOSO

    2008-12-01

    Full Text Available Working memory (WM designates the retention of objects or events in conscious awareness when these are not present in the environment. Many studies have focused on the interference properties of distracter stimuli in working memory, but these studies have mainly examined the influence of the intensity of these stimuli. Little is known about the memory modulation of hedonic content of distracter stimuli as they also may affect WM performance or attentional tasks. In this paper, we have studied the performance of a visual WM task where subjects recollect from five to eight visually presented objects while they are simultaneously exposed to additional - albeit weak- auditory or olfactory distracter stimulus. We found that WM performance decreases as the number of Ítems to remember increases, but this performance was unaltered by any of the distracter stimuli. However, when performance was correlated to the subject's perceived hedonic valúes, distracter stimuli classified as negative exhibit higher error rates than positive, neutral or control stimuli. We demónstrate that some hedonic content of otherwise neutral stimuli can strongly modulate memory processes.

  6. Age-Modulated Associations between KIBRA, Brain Volume, and Verbal Memory among Healthy Older Adults

    Ariana Stickel

    2018-01-01

    Full Text Available The resource modulation hypothesis suggests that the influence of genes on cognitive functioning increases with age. The KIBRA single nucleotide polymorphism rs17070145, associated with episodic memory and working memory, has been suggested to follow such a pattern, but few studies have tested this assertion directly. The present study investigated the relationship between KIBRA alleles (T carriers vs. CC homozygotes, cognitive performance, and brain volumes in three groups of cognitively healthy adults—middle aged (ages 52–64, n = 38, young old (ages 65–72, n = 45, and older old (ages 73–92, n = 62—who were carefully matched on potentially confounding variables including apolipoprotein ε4 status and hypertension. Consistent with our prediction, T carriers maintained verbal memory performance with increasing age while CC homozygotes declined. Voxel-based morphometric analysis of magnetic resonance images showed an advantage for T carriers in frontal white matter volume that increased with age. Focusing on the older old group, this advantage for T carriers was also evident in left lingual gyrus gray matter and several additional frontal white matter regions. Contrary to expectations, neither KIBRA nor the interaction between KIBRA and age predicted hippocampal volumes. None of the brain regions investigated showed a CC homozygote advantage. Taken together, these data suggest that KIBRA results in decreased verbal memory performance and lower brain volumes in CC homozygotes compared to T carriers, particularly among the oldest old, consistent with the resource modulation hypothesis.

  7. Threshold-voltage modulated phase change heterojunction for application of high density memory

    Yan, Baihan; Tong, Hao; Qian, Hang; Miao, Xiangshui

    2015-01-01

    Phase change random access memory is one of the most important candidates for the next generation non-volatile memory technology. However, the ability to reduce its memory size is compromised by the fundamental limitations inherent in the CMOS technology. While 0T1R configuration without any additional access transistor shows great advantages in improving the storage density, the leakage current and small operation window limit its application in large-scale arrays. In this work, phase change heterojunction based on GeTe and n-Si is fabricated to address those problems. The relationship between threshold voltage and doping concentration is investigated, and energy band diagrams and X-ray photoelectron spectroscopy measurements are provided to explain the results. The threshold voltage is modulated to provide a large operational window based on this relationship. The switching performance of the heterojunction is also tested, showing a good reverse characteristic, which could effectively decrease the leakage current. Furthermore, a reliable read-write-erase function is achieved during the tests. Phase change heterojunction is proposed for high-density memory, showing some notable advantages, such as modulated threshold voltage, large operational window, and low leakage current

  8. Threshold-voltage modulated phase change heterojunction for application of high density memory

    Yan, Baihan; Tong, Hao; Qian, Hang; Miao, Xiangshui

    2015-09-01

    Phase change random access memory is one of the most important candidates for the next generation non-volatile memory technology. However, the ability to reduce its memory size is compromised by the fundamental limitations inherent in the CMOS technology. While 0T1R configuration without any additional access transistor shows great advantages in improving the storage density, the leakage current and small operation window limit its application in large-scale arrays. In this work, phase change heterojunction based on GeTe and n-Si is fabricated to address those problems. The relationship between threshold voltage and doping concentration is investigated, and energy band diagrams and X-ray photoelectron spectroscopy measurements are provided to explain the results. The threshold voltage is modulated to provide a large operational window based on this relationship. The switching performance of the heterojunction is also tested, showing a good reverse characteristic, which could effectively decrease the leakage current. Furthermore, a reliable read-write-erase function is achieved during the tests. Phase change heterojunction is proposed for high-density memory, showing some notable advantages, such as modulated threshold voltage, large operational window, and low leakage current.

  9. Comparison of a new noncoplanar intensity-modulated radiation therapy technique for craniospinal irradiation with 3 coplanar techniques

    Hansen, Anders T; Lukacova, Slavka; Lassen-Ramshad, Yasmin A.

    2015-01-01

    When standard conformal x-ray technique for craniospinal irradiation is used, it is a challenge to achieve satisfactory dose coverage of the target including the area of the cribriform plate, while sparing organs at risk. We present a new intensity-modulated radiation therapy (IMRT), noncoplanar...... patient using the noncoplanar IMRT-based technique, a coplanar IMRT-based technique, and a coplanar volumetric-modulated arch therapy (VMAT) technique. Dosimetry data for all patients were compared with the corresponding data from the conventional treatment plans. The new noncoplanar IMRT technique...... substantially reduced the mean dose to organs at risk compared with the standard radiation technique. The 2 other coplanar techniques also reduced the mean dose to some of the critical organs. However, this reduction was not as substantial as the reduction obtained by the noncoplanar technique. Furthermore...

  10. Auditory Verbal Working Memory as a Predictor of Speech Perception in Modulated Maskers in Listeners with Normal Hearing

    Millman, Rebecca E.; Mattys, Sven L.

    2017-01-01

    Purpose: Background noise can interfere with our ability to understand speech. Working memory capacity (WMC) has been shown to contribute to the perception of speech in modulated noise maskers. WMC has been assessed with a variety of auditory and visual tests, often pertaining to different components of working memory. This study assessed the…

  11. Open-Loop Wide-Bandwidth Phase Modulation Techniques

    Nitin Nidhi

    2011-01-01

    Full Text Available The ever-increasing growth in the bandwidth of wireless communication channels requires the transmitter to be wide-bandwidth and power-efficient. Polar and outphasing transmitter topologies are two promising candidates for such applications, in future. Both these architectures require a wide-bandwidth phase modulator. Open-loop phase modulation presents a viable solution for achieving wide-bandwidth operation. An overview of prior art and recent approaches for phase modulation is presented in this paper. Phase quantization noise cancellation was recently introduced to lower the out-of-band noise in a digital phase modulator. A detailed analysis on the impact of timing and quantization of the cancellation signal is presented. Noise generated by the transmitter in the receive band frequency poses another challenge for wide-bandwidth transmitter design. Addition of a noise transfer function notch, in a digital phase modulator, to reduce the noise in the receive band during phase modulation is described in this paper.

  12. A Testable Design Method for Memories by Boundary Scan Technique

    Qiao Guo-Hui

    2016-01-01

    Full Text Available This paper presents a design for test the embedded flash in an object System-on-a-chip (SoC. The feature of the Flash TAP (Test Access Port complies with the IEEE std.1149.1, and it can select different scan chains and other control registers for other test. By the trade-off between the test time and the circuit area, an IST (In System Test circuit is designed in the SoC. Experiment results on the embedded memory have shown that the proposed method costs small testing timing by the use of IST.

  13. Angiotensin-(1-7)/Mas axis modulates fear memory and extinction in mice.

    Lazaroni, Thiago Luiz do Nascimento; Bastos, Cristiane Perácio; Moraes, Márcio Flávio Dutra; Santos, Robson Souza; Pereira, Grace Schenatto

    2016-01-01

    Inappropriate defense-alerting reaction to fear is a common feature of neuropsychiatric diseases. Therefore, impairments in brain circuits, as well as in molecular pathways underlying the neurovegetative adjustments to fear may play an essential role on developing neuropsychiatric disorders. Here we tested the hypothesis that interfering with angiotensin-(1-7) [Ang-(1-7)]/Mas receptor axis homeostasis, which appears to be essential to arterial pressure control, would affect fear memory and extinction. Mas knockout (MasKO) mice, in FVB/N background, showed normal cued fear memory and extinction, but increased freezing in response to context. Next, as FVB/N has poor performance in contextual fear memory, we tested MasKO in mixed 129xC57BL/6 background. MasKO mice behaved similarly to wild-type (WT), but memory extinction was slower in contextual fear conditioning to a weak protocol (1CS/US). In addition, delayed extinction in MasKO mice was even more pronounced after a stronger protocol (3CS/US). We showed previously that Angiotensin II receptor AT1 antagonist, losantan, rescued object recognition memory deficit in MasKO mice. Here, losartan was also effective. Memory extinction was accelerated in MasKO mice after treatment with losartan. In conclusion, we showed for the first time that Ang-(1-7)/Mas axis may modulate fear memory extinction. Furthermore, we suggest MasKO mice as an animal model to study post-traumatic stress disorder (PTSD). Copyright © 2015 Elsevier Inc. All rights reserved.

  14. Load Modulation of BOLD Response and Connectivity Predicts Working Memory Performance in Younger and Older Adults

    Nagel, Irene E.; Preuschhof, Claudia; Li, Shu-Chen; Nyberg, Lars; Backman, Lars; Lindenberger, Ulman; Heekeren, Hauke R.

    2011-01-01

    Individual differences in working memory (WM) performance have rarely been related to individual differences in the functional responsivity of the WM brain network. By neglecting person-to-person variation, comparisons of network activity between younger and older adults using functional imaging techniques often confound differences in activity…

  15. Translation techniques for distributed-shared memory programming models

    Fuller, Douglas James [Iowa State Univ., Ames, IA (United States)

    2005-01-01

    The high performance computing community has experienced an explosive improvement in distributed-shared memory hardware. Driven by increasing real-world problem complexity, this explosion has ushered in vast numbers of new systems. Each new system presents new challenges to programmers and application developers. Part of the challenge is adapting to new architectures with new performance characteristics. Different vendors release systems with widely varying architectures that perform differently in different situations. Furthermore, since vendors need only provide a single performance number (total MFLOPS, typically for a single benchmark), they only have strong incentive initially to optimize the API of their choice. Consequently, only a fraction of the available APIs are well optimized on most systems. This causes issues porting and writing maintainable software, let alone issues for programmers burdened with mastering each new API as it is released. Also, programmers wishing to use a certain machine must choose their API based on the underlying hardware instead of the application. This thesis argues that a flexible, extensible translator for distributed-shared memory APIs can help address some of these issues. For example, a translator might take as input code in one API and output an equivalent program in another. Such a translator could provide instant porting for applications to new systems that do not support the application's library or language natively. While open-source APIs are abundant, they do not perform optimally everywhere. A translator would also allow performance testing using a single base code translated to a number of different APIs. Most significantly, this type of translator frees programmers to select the most appropriate API for a given application based on the application (and developer) itself instead of the underlying hardware.

  16. Amygdala modulation of memory-related processes in the hippocampus: potential relevance to PTSD.

    Tsoory, M M; Vouimba, R M; Akirav, I; Kavushansky, A; Avital, A; Richter-Levin, G

    2008-01-01

    A key assumption in the study of stress-induced cognitive and neurobiological modifications is that alterations in hippocampal functioning after stress are due to an excessive activity exerted by the amygdala on the hippocampus. Research so far focused on stress-induced impairment of hippocampal plasticity and memory but an exposure to stress may simultaneously also result in strong emotional memories. In fact, under normal conditions emotionally charged events are better remembered compared with neutral ones. Results indicate that under these conditions there is an increase in activity within the amygdala that may lead to memory of a different quality. Studying the way emotionality activates the amygdala and the functional impact of this activation we found that the amygdala modulates memory-related processes in other brain areas, such as the hippocampus. However, this modulation is complex, involving both enhancing and suppressing effects, depending on the way the amygdala is activated and the hippocampal subregion examined. The current review summarizes our findings and attempts to put them in context with the impact of an exposure to a traumatic experience, in which there is a mixture of a strong memory of some aspects of the experience but impaired memory of other aspects of that experience. Toward that end, we have recently developed an animal model for the induction of predisposition to stress-related disorders, focusing on the consequences of exposure to stressors during juvenility on the ability to cope with stress in adulthood. Exposing juvenile-stressed rats to an additional stressful challenge in adulthood revealed their impairment to cope with stress and resulted in significant elevation of the amygdala. Interestingly, and similar to our electrophysiological findings, differential effects were observed between the impact of the emotional challenge on CA1 and dentate gyrus subregions of the hippocampus. Taken together, the results indicate that long

  17. Do TRPC channels support working memory? Comparing modulations of TRPC channels and working memory through G-protein coupled receptors and neuromodulators.

    Reboreda, Antonio; Theissen, Frederik M; Valero-Aracama, Maria J; Arboit, Alberto; Corbu, Mihaela A; Yoshida, Motoharu

    2018-03-01

    Working memory is a crucial ability we use in daily life. However, the cellular mechanisms supporting working memory still remain largely unclear. A key component of working memory is persistent neural firing which is believed to serve short-term (hundreds of milliseconds up to tens of seconds) maintenance of necessary information. In this review, we will focus on the role of transient receptor potential canonical (TRPC) channels as a mechanism underlying persistent firing. Many years of in vitro work have been suggesting a crucial role of TRPC channels in working memory and temporal association tasks. If TRPC channels are indeed a central mechanism for working memory, manipulations which impair or facilitate working memory should have a similar effect on TRPC channel modulation. However, modulations of working memory and TRPC channels were never systematically compared, and it remains unanswered whether TRPC channels indeed contribute to working memory in vivo or not. In this article, we review the effects of G-protein coupled receptors (GPCR) and neuromodulators, including acetylcholine, noradrenalin, serotonin and dopamine, on working memory and TRPC channels. Based on comparisons, we argue that GPCR and downstream signaling pathways that activate TRPC, generally support working memory, while those that suppress TRPC channels impair it. However, depending on the channel types, areas, and systems tested, this is not the case in all studies. Further work to clarify involvement of specific TRPC channels in working memory tasks and how they are affected by neuromodulators is still necessary in the future. Copyright © 2018 Elsevier B.V. All rights reserved.

  18. Nicotinic modulation of hippocampal cell signaling and associated effects on learning and memory.

    Kutlu, Munir Gunes; Gould, Thomas J

    2016-03-01

    The hippocampus is a key brain structure involved in synaptic plasticity associated with long-term declarative memory formation. Importantly, nicotine and activation of nicotinic acetylcholine receptors (nAChRs) can alter hippocampal plasticity and these changes may occur through modulation of hippocampal kinases and transcription factors. Hippocampal kinases such as cAMP-dependent protein kinase (PKA), calcium/calmodulin-dependent protein kinases (CAMKs), extracellular signal-regulated kinases 1 and 2 (ERK1/2), and c-jun N-terminal kinase 1 (JNK1), and the transcription factor cAMP-response element-binding protein (CREB) that are activated either directly or indirectly by nicotine may modulate hippocampal plasticity and in parallel hippocampus-dependent learning and memory. Evidence suggests that nicotine may alter hippocampus-dependent learning by changing the time and magnitude of activation of kinases and transcription factors normally involved in learning and by recruiting additional cell signaling molecules. Understanding how nicotine alters learning and memory will advance basic understanding of the neural substrates of learning and aid in understanding mental disorders that involve cognitive and learning deficits. Copyright © 2015 Elsevier Inc. All rights reserved.

  19. DREAM (Downstream Regulatory Element Antagonist Modulator contributes to synaptic depression and contextual fear memory

    Wu Long-Jun

    2010-01-01

    Full Text Available Abstract The downstream regulatory element antagonist modulator (DREAM, a multifunctional Ca2+-binding protein, binds specifically to DNA and several nucleoproteins regulating gene expression and with proteins outside the nucleus to regulate membrane excitability or calcium homeostasis. DREAM is highly expressed in the central nervous system including the hippocampus and cortex; however, the roles of DREAM in hippocampal synaptic transmission and plasticity have not been investigated. Taking advantage of transgenic mice overexpressing a Ca2+-insensitive DREAM mutant (TgDREAM, we used integrative methods including electrophysiology, biochemistry, immunostaining, and behavior tests to study the function of DREAM in synaptic transmission, long-term plasticity and fear memory in hippocampal CA1 region. We found that NMDA receptor but not AMPA receptor-mediated current was decreased in TgDREAM mice. Moreover, synaptic plasticity, such as long-term depression (LTD but not long-term potentiation (LTP, was impaired in TgDREAM mice. Biochemical experiments found that DREAM interacts with PSD-95 and may inhibit NMDA receptor function through this interaction. Contextual fear memory was significantly impaired in TgDREAM mice. By contrast, sensory responses to noxious stimuli were not affected. Our results demonstrate that DREAM plays a novel role in postsynaptic modulation of the NMDA receptor, and contributes to synaptic plasticity and behavioral memory.

  20. Absolute rate measurement by light modulation - ESR technique

    Choo, K Y; Gaspar, P P

    1977-01-01

    A rate constant is deduced for the reaction of tert-butoxy radicals and trimethylsilane from the measurement of the phase shift between the modulated light source and the ESR signal of trimethylsilyl radical. The rate constant was found to be 3 x 10/sup -2/M/sup -1/. sec/sup -1/ at -50/sup 0/C.

  1. Advanced Modulation Techniques for High-Performance Computing Optical Interconnects

    Karinou, Fotini; Borkowski, Robert; Zibar, Darko

    2013-01-01

    We experimentally assess the performance of a 64 × 64 optical switch fabric used for ns-speed optical cell switching in supercomputer optical interconnects. More specifically, we study four alternative modulation formats and detection schemes, namely, 10-Gb/s nonreturn-to-zero differential phase-...

  2. HDAC inhibition modulates hippocampus-dependent long-term memory for object location in a CBP-dependent manner

    Haettig, Jakob; Stefanko, Daniel P.; Multani, Monica L.; Figueroa, Dario X.; McQuown, Susan C.; Wood, Marcelo A.

    2011-01-01

    Transcription of genes required for long-term memory not only involves transcription factors, but also enzymatic protein complexes that modify chromatin structure. Chromatin-modifying enzymes, such as the histone acetyltransferase (HAT) CREB (cyclic-AMP response element binding) binding protein (CBP), are pivotal for the transcriptional regulation required for long-term memory. Several studies have shown that CBP and histone acetylation are necessary for hippocampus-dependent long-term memory and hippocampal long-term potentiation (LTP). Importantly, every genetically modified Cbp mutant mouse exhibits long-term memory impairments in object recognition. However, the role of the hippocampus in object recognition is controversial. To better understand how chromatin-modifying enzymes modulate long-term memory for object recognition, we first examined the role of the hippocampus in retrieval of long-term memory for object recognition or object location. Muscimol inactivation of the dorsal hippocampus prior to retrieval had no effect on long-term memory for object recognition, but completely blocked long-term memory for object location. This was consistent with experiments showing that muscimol inactivation of the hippocampus had no effect on long-term memory for the object itself, supporting the idea that the hippocampus encodes spatial information about an object (such as location or context), whereas cortical areas (such as the perirhinal or insular cortex) encode information about the object itself. Using location-dependent object recognition tasks that engage the hippocampus, we demonstrate that CBP is essential for the modulation of long-term memory via HDAC inhibition. Together, these results indicate that HDAC inhibition modulates memory in the hippocampus via CBP and that different brain regions utilize different chromatin-modifying enzymes to regulate learning and memory. PMID:21224411

  3. The basolateral amygdala modulates specific sensory memory representations in the cerebral cortex.

    Chavez, Candice M; McGaugh, James L; Weinberger, Norman M

    2009-05-01

    Stress hormones released by an experience can modulate memory strength via the basolateral amygdala, which in turn acts on sites of memory storage such as the cerebral cortex [McGaugh, J. L. (2004). The amygdala modulates the consolidation of memories of emotionally arousing experiences. Annual Review of Neuroscience, 27, 1-28]. Stimuli that acquire behavioral importance gain increased representation in the cortex. For example, learning shifts the tuning of neurons in the primary auditory cortex (A1) to the frequency of a conditioned stimulus (CS), and the greater the level of CS importance, the larger the area of representational gain [Weinberger, N. M. (2007). Associative representational plasticity in the auditory cortex: A synthesis of two disciplines. Learning & Memory, 14(1-2), 1-16]. The two lines of research suggest that BLA strengthening of memory might be accomplished in part by increasing the representation of an environmental stimulus. The present study investigated whether stimulation of the BLA can affect cortical memory representations. In male Sprague-Dawley rats studied under urethane general anesthesia, frequency receptive fields were obtained from A1 before and up to 75min after the pairing of a tone with BLA stimulation (BLAstm: 100 trials, 400ms, 100Hz, 400microA [+/-16.54]). Tone started before and continued after BLAstm. Group BLA/1.0 (n=16) had a 1s CS-BLAstm interval while Group BLA/1.6 (n=5) has a 1.6s interval. The BLA/1.0 group did develop specific tuning shifts toward and to the CS, which could change frequency tuning by as much as two octaves. Moreover, its shifts increased over time and were enduring, lasting 75min. However, group BLA/1.6 did not develop tuning shifts, indicating that precise CS-BLAstm timing is important in the anesthetized animal. Further, training in the BLA/1.0 paradigm but stimulating outside of the BLA did not produce tuning shifts. These findings demonstrate that the BLA is capable of exerting highly specific

  4. Two clusters of GABAergic ellipsoid body neurons modulate olfactory labile memory in Drosophila.

    Zhang, Zhiping; Li, Xiaoting; Guo, Jing; Li, Yan; Guo, Aike

    2013-03-20

    In Drosophila, aversive olfactory memory is believed to be stored in a prominent brain structure, the mushroom body (MB), and two pairs of MB intrinsic neurons, the dorsal paired medial (DPM) and the anterior paired lateral (APL) neurons, are found to regulate the consolidation of middle-term memory (MTM). Here we report that another prominent brain structure, the ellipsoid body (EB), is also involved in the modulation of olfactory MTM. Activating EB R2/R4m neurons does not affect the learning index, but specifically eliminates anesthesia-sensitive memory (ASM), the labile component of olfactory MTM. We further demonstrate that approximately two-thirds of these EB neurons are GABAergic and are responsible for the suppression of ASM. Using GRASP (GFP reconstitution across synaptic partners), we reveal potential synaptic connections between the EB and MB in regions covering both the presynaptic and postsynaptic sites of EB neurons, suggesting the presence of bidirectional connections between these two important brain structures. These findings suggest the existence of direct connections between the MB and EB, and provide new insights into the neural circuit basis for olfactory labile memory in Drosophila.

  5. Modulation of fusiform cortex activity by cholinesterase inhibition predicts effects on subsequent memory.

    Bentley, P; Driver, J; Dolan, R J

    2009-09-01

    Cholinergic influences on memory are likely to be expressed at several processing stages, including via well-recognized effects of acetylcholine on stimulus processing during encoding. Since previous studies have shown that cholinesterase inhibition enhances visual extrastriate cortex activity during stimulus encoding, especially under attention-demanding tasks, we tested whether this effect correlates with improved subsequent memory. In a within-subject physostigmine versus placebo design, we measured brain activity with functional magnetic resonance imaging while healthy and mild Alzheimer's disease subjects performed superficial and deep encoding tasks on face (and building) visual stimuli. We explored regions in which physostigmine modulation of face-selective neural responses correlated with physostigmine effects on subsequent recognition performance. In healthy subjects physostigmine led to enhanced later recognition for deep- versus superficially-encoded faces, which correlated across subjects with a physostigmine-induced enhancement of face-selective responses in right fusiform cortex during deep- versus superficial-encoding tasks. In contrast, the Alzheimer's disease group showed neither a depth of processing effect nor restoration of this with physostigmine. Instead, patients showed a task-independent improvement in confident memory with physostigmine, an effect that correlated with enhancements in face-selective (but task-independent) responses in bilateral fusiform cortices. Our results indicate that one mechanism by which cholinesterase inhibitors can improve memory is by enhancing extrastriate cortex stimulus selectivity at encoding, in a manner that for healthy people but not in Alzheimer's disease is dependent upon depth of processing.

  6. Selection within working memory based on a color retro-cue modulates alpha oscillations.

    Poch, Claudia; Capilla, Almudena; Hinojosa, José Antonio; Campo, Pablo

    2017-11-01

    Working Memory (WM) maintains flexible representations. Retrospective cueing studies indicate that selective attention can be directed to memory representations in WM improving performance. While most of the work has explored the neural substrates of orienting attention based on a spatial retro-cue, behavioral studies show that a feature other than location can also improve WM performance. In the present work we explored the oscillatory underpinnings of orienting attention to a relevant representation held in WM guided by a feature value. We recorded EEG data in a group of 36 healthy human subjects (20 females) performing a WM task in which they had to memorize the orientation of four rectangles of different colors. After a maintenance period, a cue was presented indicating the color of the relevant item. We showed that directing attention to a memory item based on its color resulted in a modulation of posterior alpha activity, which appears as more desynchronization in the contralateral than in the ipsilateral hemisphere. Alpha lateralization is considered a neurophysiological marker of external and internal spatial attention. We propose that current findings support the idea that selection of a memory item based on a non-location feature could be accomplished by a spatial attentional mechanism. Moreover, using a centrally presented color retro-cue allowed us to surpass the confounds inherent to the use of spatial retro-cues, supporting that the observed lateralized alpha results from an endogenous attentional mechanism. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Does caffeine modulate verbal working memory processes? An fMRI study.

    Koppelstaetter, F; Poeppel, T D; Siedentopf, C M; Ischebeck, A; Verius, M; Haala, I; Mottaghy, F M; Rhomberg, P; Golaszewski, S; Gotwald, T; Lorenz, I H; Kolbitsch, C; Felber, S; Krause, B J

    2008-01-01

    To assess the effect of caffeine on the functional MRI signal during a 2-back verbal working memory task, we examined blood oxygenation level-dependent regional brain activity in 15 healthy right-handed males. The subjects, all moderate caffeine consumers, underwent two scanning sessions on a 1.5-T MR-Scanner separated by a 24- to 48-h interval. Each participant received either placebo or 100 mg caffeine 20 min prior to the performance of the working memory task in blinded crossover fashion. The study was implemented as a blocked-design. Analysis was performed using SPM2. In both conditions, the characteristic working memory network of frontoparietal cortical activation including the precuneus and the anterior cingulate could be shown. In comparison to placebo, caffeine caused an increased response in the bilateral medial frontopolar cortex (BA 10), extending to the right anterior cingulate cortex (BA 32). These results suggest that caffeine modulates neuronal activity as evidenced by fMRI signal changes in a network of brain areas associated with executive and attentional functions during working memory processes.

  8. Ultra-High Density Holographic Memory Module with Solid-State Architecture

    Markov, Vladimir B.

    2000-01-01

    NASA's terrestrial. space, and deep-space missions require technology that allows storing. retrieving, and processing a large volume of information. Holographic memory offers high-density data storage with parallel access and high throughput. Several methods exist for data multiplexing based on the fundamental principles of volume hologram selectivity. We recently demonstrated that a spatial (amplitude-phase) encoding of the reference wave (SERW) looks promising as a way to increase the storage density. The SERW hologram offers a method other than traditional methods of selectivity, such as spatial de-correlation between recorded and reconstruction fields, In this report we present the experimental results of the SERW-hologram memory module with solid-state architecture, which is of particular interest for space operations.

  9. Electro-optic modulation measurement technique and enhancement

    Jacobsen, Rune Shim

    2005-01-01

    indeks bølgeleder blev påbegyndt. Når denne koefficient opnås i en sådan bølgeleder vil fremtidige forsøg kunne fastlægge hvor stor den inducerede ikke-lineare koefficient i silicium kan blive. Fremtidige forsøg vil også fastlægge om den inducerede effekt eksisterer for hurtig elektrisk modulation....

  10. Sensory input from the osphradium modulates the response to memory-enhancing stressors in Lymnaea stagnalis.

    Karnik, Vikram; Braun, Marvin; Dalesman, Sarah; Lukowiak, Ken

    2012-02-01

    In the freshwater environment species often rely on chemosensory information to modulate behavior. The pond snail, Lymnaea stagnalis, is a model species used to characterize the causal mechanisms of long-term memory (LTM) formation. Chemical stressors including crayfish kairomones and KCl enhance LTM formation (≥24 h) in Lymnaea; however, how these stressors are sensed and the mechanism by which they affect the electrophysiological properties of neurons necessary for memory formation are poorly understood. Here, we assessed whether the osphradium, a primary chemosensory organ in Lymnaea, modulates LTM enhancement. To test this we severed the osphradial nerve proximal to the osphradium, using sham-operated animals as controls, and assessed the behavioral and electrophysiological response to crayfish kairomones and KCl. We operantly conditioned aerial respiratory behavior in intact, sham and osphradially cut animals, and tested for enhanced memory formation after exposure to the chemical stressors. Sham-operated animals displayed the same memory enhancement as intact animals but snails with a severed osphradial nerve did not show LTM enhancement. Extracellular recordings made from the osphradial nerve demonstrate that these stressors evoked afferent sensory activity. Intracellular recordings from right pedal dorsal 1 (RPeD1), a neuron necessary for LTM formation, demonstrate that its electrophysiological activity is altered by input from the osphradium following exposure to crayfish kairomones or KCl in sham and intact animals but no response is seen in RPeD1 in osphradially cut animals. Therefore, sensory input from the osphradium is necessary for LTM enhancement following exposure to these chemical stressors.

  11. TOPEM, a new temperature modulated DSC technique - Application to the glass transition of polymers

    Fraga Rivas, Iria; Montserrat Ribas, Salvador; Hutchinson, John M.

    2007-01-01

    TOPEM is a new temperature modulated DSC technique, introduced by Mettler-Toledo in late 2005, in which stochastic temperature modulations are superimposed on the underlying rate of a conventional DSC scan. These modulations consist of temperature pulses, of fixed magnitude and alternating sign, with random durations within limits specified by the user. The resulting heat flow signal is analysed by a parameter estimation method which yields a so-called ‘quasi-static’ specific heat capac...

  12. Application of source biasing technique for energy efficient DECODER circuit design: memory array application

    Gupta, Neha; Parihar, Priyanka; Neema, Vaibhav

    2018-04-01

    Researchers have proposed many circuit techniques to reduce leakage power dissipation in memory cells. If we want to reduce the overall power in the memory system, we have to work on the input circuitry of memory architecture i.e. row and column decoder. In this research work, low leakage power with a high speed row and column decoder for memory array application is designed and four new techniques are proposed. In this work, the comparison of cluster DECODER, body bias DECODER, source bias DECODER, and source coupling DECODER are designed and analyzed for memory array application. Simulation is performed for the comparative analysis of different DECODER design parameters at 180 nm GPDK technology file using the CADENCE tool. Simulation results show that the proposed source bias DECODER circuit technique decreases the leakage current by 99.92% and static energy by 99.92% at a supply voltage of 1.2 V. The proposed circuit also improves dynamic power dissipation by 5.69%, dynamic PDP/EDP 65.03% and delay 57.25% at 1.2 V supply voltage.

  13. Employ Simulation Techniques. Second Edition. Module C-5 of Category C--Instructional Execution. Professional Teacher Education Module Series.

    Ohio State Univ., Columbus. National Center for Research in Vocational Education.

    One of a series of performance-based teacher education learning packages focusing upon specific professional competencies of vocational teachers, this learning module deals with employing simulation techniques. It consists of an introduction and four learning experiences. Covered in the first learning experience are various types of simulation…

  14. Modulation Technique for Four-Leg Voltage Source Inverter without a Look-Up Table

    Ebrahimzadeh, Esmaeil; Farhangi, Shahrokh; Iman-Eini, Hossein

    2016-01-01

    Three-dimensional space-vector modulation (3D SVM) has more popularity among the other modulation techniques of the four-leg inverter due to higher DC-link voltage utilisation. Sequencing schemes of the switching vectors in the 3D SVM are divided into Class I and II categories. Each of these clas...

  15. Nuclear Technology. Course 26: Nondestructive Examination (NDE) Techniques I. Module 26-5, Fundamentals of Radiography.

    Groseclose, Richard

    This fifth in a series of seven modules for a course titled Nondestructive Examination (NDE) Techniques I explains the radiographic process, from radiation source selection to equipment and specimen selection and arrangement, and film processing. The module follows a typical format that includes the following sections: (1) introduction, (2) module…

  16. Nuclear Technology. Course 26: Nondestructive Examination (NDE) Techniques I. Module 26-6, Radiography Inspection.

    Pelton, Rick; Espy, John

    This sixth in a series of seven modules for a course titled Nondestructive Examination (NDE) Techniques I explains radiographic inspection as a means of nondestructively examining components, assemblies, structures, and fabricated piping. The module follows a typical format that includes the following sections: (1) introduction, (2) module…

  17. Conscious Access to Suppressed Threatening Information Is Modulated by Working Memory.

    Liu, Dong; Wang, Li; Wang, Ying; Jiang, Yi

    2016-11-01

    Previous research has demonstrated that emotional information processing can be modulated by what is being held in working memory (WM). Here, we showed that such content-based WM effects can occur even when the emotional information is suppressed from conscious awareness. Using the delayed-match-to-sample paradigm in conjunction with continuous flash suppression, we found that suppressed threatening (fearful and angry) faces emerged from suppression faster when they matched the emotional valence of WM contents than when they did not. This effect cannot be explained by perceptual priming, as it disappeared when the faces were only passively viewed and not held in WM. Crucially, such an effect is highly specific to threatening faces but not to happy or neutral faces. Our findings together suggest that WM can modulate nonconscious emotion processing, which highlights the functional association between nonconsciously triggered emotional processes and conscious emotion representation. © The Author(s) 2016.

  18. Optically stimulated luminescence from quartz measured using the linear modulation technique

    Bulur, E.; Bøtter-Jensen, L.; Murray, A.S.

    2000-01-01

    The optically stimulated luminescence (OSL) from heated natural quartz has been investigated using the linear modulation technique (LMT), in which the excitation light intensity is increased linearly during stimulation. In contrast to conventional stimulation, which usually produces a monotonical...

  19. Turning negative memories around: Contingency versus devaluation techniques.

    Dibbets, Pauline; Lemmens, Anke; Voncken, Marisol

    2018-09-01

    It is assumed that fear responses can be altered by changing the contingency between a conditioned stimulus (CS) and an unconditioned stimulus (US), or by devaluing the present mental representation of the US. The aim of the present study was to compare the efficacy of contingency- and devaluation-based intervention techniques on the diminishment in - and return of fear. We hypothesized that extinction (EXT, contingency-based) would outperform devaluation-based techniques regarding contingency measures, but that devaluation-based techniques would be most effective in reducing the mental representation of the US. Additionally, we expected that incorporations of the US during devaluation would result in less reinstatement of the US averseness. Healthy participants received a fear conditioning paradigm followed by one of three interventions: extinction (EXT, contingency-based), imagery rescripting (ImRs, devaluation-based) or eye movement desensitization and reprocessing (EMDR, devaluation-based). A reinstatement procedure and test followed the next day. EXT was indeed most successful in diminishing contingency-based US expectancies and skin conductance responses (SCRs), but all interventions were equally successful in reducing the averseness of the mental US representation. After reinstatement EXT showed lowest expectancies and SCRs; no differences were observed between the conditions concerning the mental US representation. A partial reinforcement schedule was used, resulting in a vast amount of contingency unaware participants. Additionally, a non-clinical sample was used, which may limit the generalizability to clinical populations. EXT is most effective in reducing conditioned fear responses. Copyright © 2018 Elsevier Ltd. All rights reserved.

  20. Auditory Verbal Working Memory as a Predictor of Speech Perception in Modulated Maskers in Listeners With Normal Hearing.

    Millman, Rebecca E; Mattys, Sven L

    2017-05-24

    Background noise can interfere with our ability to understand speech. Working memory capacity (WMC) has been shown to contribute to the perception of speech in modulated noise maskers. WMC has been assessed with a variety of auditory and visual tests, often pertaining to different components of working memory. This study assessed the relationship between speech perception in modulated maskers and components of auditory verbal working memory (AVWM) over a range of signal-to-noise ratios. Speech perception in noise and AVWM were measured in 30 listeners (age range 31-67 years) with normal hearing. AVWM was estimated using forward digit recall, backward digit recall, and nonword repetition. After controlling for the effects of age and average pure-tone hearing threshold, speech perception in modulated maskers was related to individual differences in the phonological component of working memory (as assessed by nonword repetition) but only in the least favorable signal-to-noise ratio. The executive component of working memory (as assessed by backward digit) was not predictive of speech perception in any conditions. AVWM is predictive of the ability to benefit from temporal dips in modulated maskers: Listeners with greater phonological WMC are better able to correctly identify sentences in modulated noise backgrounds.

  1. Transcranial direct current stimulation improves long-term memory deficits in an animal model of attention-deficit/hyperactivity disorder and modulates oxidative and inflammatory parameters.

    Leffa, Douglas Teixeira; Bellaver, Bruna; Salvi, Artur Alban; de Oliveira, Carla; Caumo, Wolnei; Grevet, Eugenio Horacio; Fregni, Felipe; Quincozes-Santos, André; Rohde, Luis Augusto; Torres, Iraci L S

    2018-04-05

    Transcranial direct current stimulation (tDCS) is a technique that modulates neuronal activity and has been proposed as a potential therapeutic tool for attention-deficit/hyperactivity disorder (ADHD) symptoms. Although pilot studies have shown evidence of efficacy, its mechanism of action remains unclear. We evaluated the effects of tDCS on behavioral (working and long-term memory) and neurochemical (oxidative and inflammatory parameters) outcomes related to ADHD pathophysiology. We used the most widely accepted animal model of ADHD: spontaneously hypertensive rats (SHR). The selected behavioral outcomes have been shown to be altered in both ADHD patients and animal models, and were chosen for their relation to the proposed mechanistic action of tDCS. Adult male SHR and their control, the Wistar Kyoto rats (WKY), were subjected to 20 min of bicephalic tDCS or sham stimulation for 8 consecutive days. Working memory, long-term memory, and neurochemical outcomes were evaluated. TDCS improved long-term memory deficits presented by the SHR. No change in working memory performance was observed. In the hippocampus, tDCS increased both the production of reactive oxygen species in SHR and the levels of the antioxidant molecule glutathione in both strains. TDCS also modulated inflammatory response in the brains of WKY by downregulating pro-inflammatory cytokines. TDCS had significant effects that were specific for strain, type of behavioral and neurochemical outcomes. The long-term memory improvement in the SHR may point to a possible therapeutic role of tDCS in ADHD that does not seem to be mediated by inflammatory markers. Additionally, the anti-inflammatory effects observed in the brain of WKY after tDCS needs to be further explored. Copyright © 2018 Elsevier Inc. All rights reserved.

  2. A Processing Technique for OFDM-Modulated Wideband Radar Signals

    Tigrek, R.F.

    2010-01-01

    The orthogonal frequency division multiplexing (OFDM) is a multicarrier spread-spectrum technique which finds wide-spread use in communications. The OFDM pulse compression method that utilizes an OFDM communication signal for radar tasks has been developed and reported in this dissertation. Using

  3. Applying Hamming Code to Memory System of Safety Grade PLC (POSAFE-Q) Processor Module

    Kim, Taehee; Hwang, Sungjae; Park, Gangmin

    2013-01-01

    If some errors such as inverted bits occur in the memory, instructions and data will be corrupted. As a result, the PLC may execute the wrong instructions or refer to the wrong data. Hamming Code can be considered as the solution for mitigating this mis operation. In this paper, we apply hamming Code, then, we inspect whether hamming code is suitable for to the memory system of the processor module. In this paper, we applied hamming code to existing safety grade PLC (POSAFE-Q). Inspection data are collected and they will be referred for improving the PLC in terms of the soundness. In our future work, we will try to improve time delay caused by hamming calculation. It will include CPLD optimization and memory architecture or parts alteration. In addition to these hamming code-based works, we will explore any methodologies such as mirroring for the soundness of safety grade PLC. Hamming code-based works can correct bit errors, but they have limitation in multi bits errors

  4. Brain mechanisms of persuasion: how 'expert power' modulates memory and attitudes.

    Klucharev, Vasily; Smidts, Ale; Fernández, Guillén

    2008-12-01

    Human behaviour is affected by various forms of persuasion. The general persuasive effect of high expertise of the communicator, often referred to as 'expert power', is well documented. We found that a single exposure to a combination of an expert and an object leads to a long-lasting positive effect on memory for and attitude towards the object. Using functional magnetic resonance imaging, we probed the neural processes predicting these behavioural effects. Expert context was associated with distributed left-lateralized brain activity in prefrontal and temporal cortices related to active semantic elaboration. Furthermore, experts enhanced subsequent memory effects in the medial temporal lobe (i.e. in hippocampus and parahippocampal gyrus) involved in memory formation. Experts also affected subsequent attitude effects in the caudate nucleus involved in trustful behaviour, reward processing and learning. These results may suggest that the persuasive effect of experts is mediated by modulation of caudate activity resulting in a re-evaluation of the object in terms of its perceived value. Results extend our view of the functional role of the dorsal striatum in social interaction and enable us to make the first steps toward a neuroscientific model of persuasion.

  5. Brain mechanisms of persuasion: how ‘expert power’ modulates memory and attitudes

    Smidts, Ale; Fernández, Guillén

    2008-01-01

    Human behaviour is affected by various forms of persuasion. The general persuasive effect of high expertise of the communicator, often referred to as ’expert power’, is well documented. We found that a single exposure to a combination of an expert and an object leads to a long-lasting positive effect on memory for and attitude towards the object. Using functional magnetic resonance imaging, we probed the neural processes predicting these behavioural effects. Expert context was associated with distributed left-lateralized brain activity in prefrontal and temporal cortices related to active semantic elaboration. Furthermore, experts enhanced subsequent memory effects in the medial temporal lobe (i.e. in hippocampus and parahippocampal gyrus) involved in memory formation. Experts also affected subsequent attitude effects in the caudate nucleus involved in trustful behaviour, reward processing and learning. These results may suggest that the persuasive effect of experts is mediated by modulation of caudate activity resulting in a re-evaluation of the object in terms of its perceived value. Results extend our view of the functional role of the dorsal striatum in social interaction and enable us to make the first steps toward a neuroscientific model of persuasion. PMID:19015077

  6. Applying Hamming Code to Memory System of Safety Grade PLC (POSAFE-Q) Processor Module

    Kim, Taehee; Hwang, Sungjae; Park, Gangmin [POSCO Nuclear Technology, Seoul (Korea, Republic of)

    2013-05-15

    If some errors such as inverted bits occur in the memory, instructions and data will be corrupted. As a result, the PLC may execute the wrong instructions or refer to the wrong data. Hamming Code can be considered as the solution for mitigating this mis operation. In this paper, we apply hamming Code, then, we inspect whether hamming code is suitable for to the memory system of the processor module. In this paper, we applied hamming code to existing safety grade PLC (POSAFE-Q). Inspection data are collected and they will be referred for improving the PLC in terms of the soundness. In our future work, we will try to improve time delay caused by hamming calculation. It will include CPLD optimization and memory architecture or parts alteration. In addition to these hamming code-based works, we will explore any methodologies such as mirroring for the soundness of safety grade PLC. Hamming code-based works can correct bit errors, but they have limitation in multi bits errors.

  7. Event-related potential responses to perceptual reversals are modulated by working memory load.

    Intaitė, Monika; Koivisto, Mika; Castelo-Branco, Miguel

    2014-04-01

    While viewing ambiguous figures, such as the Necker cube, the available perceptual interpretations alternate with one another. The role of higher level mechanisms in such reversals remains unclear. We tested whether perceptual reversals of discontinuously presented Necker cube pairs depend on working memory resources by manipulating cognitive load while recording event-related potentials (ERPs). The ERPs showed early enhancements of negativity, which were obtained in response to the first cube approximately 500 ms before perceived reversals. We found that working memory load influenced reversal-related brain responses in response to the second cube over occipital areas at the 150-300 ms post-stimulus and over central areas at P3 time window (300-500 ms), suggesting that it modulates intermediate visual processes. Interestingly, reversal rates remained unchanged by the working memory load. We propose that perceptual reversals in discontinuous presentation of ambiguous stimuli are governed by an early (well preceding pending reversals) mechanism, while the effects of load on the reversal related ERPs may reflect general top-down influences on visual processing, possibly mediated by the prefrontal cortex. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. Modified Dual Three-Pulse Modulation technique for single-phase inverter topology

    Sree Harsha, N. R.; Anitha, G. S.; Sreedevi, A.

    2016-01-01

    In a recent paper, a new modulation technique called Dual Three Pulse Modulation (DTPM) was proposed to improve the efficiency of the power converters of the Electric/Hybrid/Fuel-cell vehicles. It was simulated in PSIM 9.0.4 and uses analog multiplexers to generate the modulating signals for the DC/DC converter and inverter. The circuit used is complex and many other simulation softwares do not support the analog multiplexers as well. Also, the DTPM technique produces modulating signals for the converter, which are essentially needed to produce the modulating signals for the inverter. Hence, it cannot be used efficiently to switch the valves of a stand-alone inverter. We propose a new method to generate the modulating signals to switch MOSFETs of a single phase Dual-Three pulse Modulation based stand-alone inverter. The circuits proposed are simulated in Multisim 12.0. We also show an alternate way to switch a DC/DC converter in a way depicted by DTPM technique both in simulation (MATLAB/Simulink) and hardware. The circuitry is relatively simple and can be used for the further investigations of DTPM technique.

  9. Modulation of sensorimotor circuits during retrieval of negative Autobiographical Memories: Exploring the impact of personality dimensions.

    Mineo, Ludovico; Concerto, Carmen; Patel, Dhaval; Mayorga, Tyrone; Chusid, Eileen; Infortuna, Carmenrita; Aguglia, Eugenio; Sarraf, Yasmin; Battaglia, Fortunato

    2018-02-01

    Autobiographical Memory (AM) retrieval refers to recollection of experienced past events. Previous Transcranial Magnetic Stimulation (TMS) studies have shown that presentation of emotional negative stimuli affects human motor cortex excitability resulting in larger motor evoked potentials (MEPs). Up to date no TMS studies have been carried out in order to investigate the effect of personal memories with negative emotional value on corticospinal excitability. In this study we hypothesized that negative AM retrieval will modulate corticomotor excitability and sensorimotor integration as determined by TMS neurophysiological parameters. Furthermore, we investigated whether TMS responses during retrieval of negative AM are associated with specific personality traits. Twelve healthy subjects were asked to recall either a negative or a neutral AM across two different days in a randomized order. During this memory retrieval, the following TMS parameters were recorded: MEPs; Short- interval intracortical inhibition (SICI) and Intracortical facilitation (ICF); Short-latency afferent inhibition (SAI) and Long- latency afferent inhibition (LAI). Personality traits were assessed by using the Big Five scale. Statistical analysis was performed using factorial ANOVAs and multiple linear regression models. When compared to retrieval of neutral AM, recollection of negative AM induced a larger increase in MEP amplitude, an increase in ICF, and a decrease in SAI. The neuroticism personality trait was a significant predictor of the MEP amplitude increase during retrieval of negative AM. Altogether these results indicate that cortical excitability and sensorimotor integration are selectively modulated by the valence of AM. These results provide the first TMS evidence that the modulatory effect of the AM retrieval is associated with specific personality traits. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. The role of the temporal pole in modulating primitive auditory memory.

    Liu, Zhiliang; Wang, Qian; You, Yu; Yin, Peng; Ding, Hu; Bao, Xiaohan; Yang, Pengcheng; Lu, Hao; Gao, Yayue; Li, Liang

    2016-04-21

    Primitive auditory memory (PAM), which is recognized as the early point in the chain of the transient auditory memory system, faithfully maintains raw acoustic fine-structure signals for up to 20-30 milliseconds. The neural mechanisms underlying PAM have not been reported in the literature. Previous anatomical, brain-imaging, and neurophysiological studies have suggested that the temporal pole (TP), part of the parahippocampal region in the transitional area between perirhinal cortex and superior/inferior temporal gyri, is involved in auditory memories. This study investigated whether the TP plays a role in mediating/modulating PAM. The longest interaural interval (the interaural-delay threshold) for detecting a break in interaural correlation (BIC) embedded in interaurally correlated wideband noises was used to indicate the temporal preservation of PAM and examined in both healthy listeners and patients receiving unilateral anterior temporal lobectomy (ATL, centered on the TP) for treating their temporal lobe epilepsy (TLE). The results showed that patients with ATL were still able to detect the BIC even when an interaural interval was introduced, regardless of which ear was the leading one. However, in patient participants, the group-mean interaural-delay threshold for detecting the BIC under the contralateral-ear-leading (relative to the side of ATL) condition was significantly shorter than that under the ipsilateral-ear-leading condition. The results suggest that although the TP is not essential for integrating binaural signals and mediating the PAM, it plays a role in top-down modulating the PAM of raw acoustic fine-structure signals from the contralateral ear. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  11. NeuroD modulates opioid agonist-selective regulation of adult neurogenesis and contextual memory extinction.

    Zheng, Hui; Zhang, Yue; Li, Wen; Loh, Horace H; Law, Ping-Yee

    2013-04-01

    Addictive drugs, including opioids, modulate adult neurogenesis. In order to delineate the probable implications of neurogenesis on contextual memory associated with addiction, we investigated opioid agonist-selective regulation of neurogenic differentiation 1 (NeuroD) activities under the conditioned place preference (CPP) paradigm. Training mice with equivalent doses of morphine and fentanyl produced different CPP extinction rates without measurable differences in the CPP acquisition rate or magnitude. Fentanyl-induced CPP required much longer time for extinction than morphine-induced CPP. We observed a parallel decrease in NeuroD activities and neurogenesis after morphine-induced CPP, but not after fentanyl-induced CPP. Increasing NeuroD activities with NeuroD-lentivirus (nd-vir) injection at the dentate gyrus before CPP training reversed morphine-induced decreases in NeuroD activities and neurogenesis, and prolonged the time required for extinction of morphine-induced CPP. On the other hand, decreasing NeuroD activities via injection of miRNA-190-virus (190-vir) reversed the fentanyl effect on NeuroD and neurogenesis and shortened the time required for extinction of fentanyl-induced CPP. Another contextual memory task, the Morris Water Maze (MWM), was affected similarly by alteration of NeuroD activities. The reduction in NeuroD activities either by morphine treatment or 190-vir injection decreased MWM task retention, while the increase in NeuroD activities by nd-vir prolonged MWM task retention. Thus, by controlling NeuroD activities, opioid agonists differentially regulate adult neurogenesis and subsequent contextual memory retention. Such drug-related memory regulation could have implications in eventual context-associated relapse.

  12. Enhancing and impairing extinction of habit memory through modulation of NMDA receptors in the dorsolateral striatum.

    Goodman, Jarid; Ressler, Reed L; Packard, Mark G

    2017-06-03

    The present experiments investigated the involvement of N-methyl-d-aspartate (NMDA) receptors of the dorsolateral striatum (DLS) in consolidation of extinction in a habit memory task. Adult male Long-Evans rats were initially trained in a food-reinforced response learning version of a plus-maze task and were subsequently given extinction training in which the food was removed from the maze. In experiment 1, immediately after the first day of extinction training, rats received bilateral intra-DLS injections of the NMDA receptor antagonist 2-amino-5-phosphonopentanoic acid (AP5; 2µg/side) or physiological saline. In experiment 2, immediately following the first day of extinction training, animals were given intra-DLS injections of NMDA receptor partial agonist d-cycloserine (DCS; 10 or 20µg/side) or saline. In both experiments, the number of perseverative trials (a trial in which a rat made the same previously reinforced body-turn response) and latency to reach the previously correct food well were used as measures of extinction behavior. Results indicated that post-training intra-DLS injections of AP5 impaired extinction. In contrast, post-training intra-DLS infusions of DCS (20µg) enhanced extinction. Intra-DLS administration of AP5 or DCS given two hours after extinction training did not influence extinction of response learning, indicating that immediate post-training administration of AP5 and DCS specifically influenced consolidation of the extinction memory. The present results indicate a critical role for DLS NMDA receptors in modulating extinction of habit memory and may be relevant to developing therapeutic approaches to combat the maladaptive habits observed in human psychopathologies in which DLS-dependent memory has been implicated (e.g. drug addiction and relapse and obsessive compulsive disorder). Copyright © 2017 IBRO. Published by Elsevier Ltd. All rights reserved.

  13. Mineralocorticoid receptor blockade prevents stress-induced modulation of multiple memory systems in the human brain.

    Schwabe, Lars; Tegenthoff, Martin; Höffken, Oliver; Wolf, Oliver T

    2013-12-01

    Accumulating evidence suggests that stress may orchestrate the engagement of multiple memory systems in the brain. In particular, stress is thought to favor dorsal striatum-dependent procedural over hippocampus-dependent declarative memory. However, the neuroendocrine mechanisms underlying these modulatory effects of stress remain elusive, especially in humans. Here, we targeted the role of the mineralocorticoid receptor (MR) in the stress-induced modulation of dorsal striatal and hippocampal memory systems in the human brain using a combination of event-related functional magnetic resonance imaging and pharmacologic blockade of the MR. Eighty healthy participants received the MR antagonist spironolactone (300 mg) or a placebo and underwent a stressor or control manipulation before they performed, in the scanner, a classification task that can be supported by the hippocampus and the dorsal striatum. Stress after placebo did not affect learning performance but reduced explicit task knowledge and led to a relative increase in the use of more procedural learning strategies. At the neural level, stress promoted striatum-based learning at the expense of hippocampus-based learning. Functional connectivity analyses showed that this shift was associated with altered coupling of the amygdala with the hippocampus and dorsal striatum. Mineralocorticoid receptor blockade before stress prevented the stress-induced shift toward dorsal striatal procedural learning, same as the stress-induced alterations of amygdala connectivity with hippocampus and dorsal striatum, but resulted in significantly impaired performance. Our findings indicate that the stress-induced shift from hippocampal to dorsal striatal memory systems is mediated by the amygdala, required to preserve performance after stress, and dependent on the MR. © 2013 Society of Biological Psychiatry.

  14. Energy drinks and their component modulate attention, memory, and antioxidant defences in rats.

    Valle, M T Costa; Couto-Pereira, N S; Lampert, C; Arcego, D M; Toniazzo, A P; Limberger, R P; Dallegrave, E; Dalmaz, C; Arbo, M D; Leal, M B

    2017-08-12

    This study aimed to evaluate the effects of the subchronic consumption of energy drinks and their constituents (caffeine and taurine) in male Wistar rats using behavioural and oxidative measures. Energy drinks (ED 5, 7.5, and 10 mL/kg) or their constituents, caffeine (3.2 mg/kg) and taurine (40 mg/kg), either separately or in combination, were administered orally to animals for 28 days. Attention was measured though the ox-maze apparatus and the object recognition memory test. Following behavioural analyses, markers of oxidative stress, including SOD, CAT, GPx, thiol content, and free radicals, were measured in the prefrontal cortex, hippocampus, and striatum. The latency time to find the first reward was lower in animals that received caffeine, taurine, or a combination of both (P = 0.003; ANOVA/Bonferroni). In addition, these animals took less time to complete the ox-maze task (P = 0.0001; ANOVA/Bonferroni), and had better short-term memory (P caffeine and taurine, there was a significant increase in the production of free radicals in the prefrontal cortex and in the hippocampus (P caffeine and taurine improved memory and attention, and led to an imbalance in the antioxidant defence system. These results differed from those of the group that was exposed to the energy drink. This might be related to other components contained in the energy drink, such as vitamins and minerals, which may have altered the ability of caffeine and taurine to modulate memory and attention.

  15. Hippocampal dendritic spines remodeling and fear memory are modulated by GABAergic signaling within the basolateral amygdala complex.

    Giachero, Marcelo; Calfa, Gaston D; Molina, Victor A

    2015-05-01

    GABAergic signaling in the basolateral amygdala complex (BLA) plays a crucial role on the modulation of the stress influence on fear memory. Moreover, accumulating evidence suggests that the dorsal hippocampus (DH) is a downstream target of BLA neurons in contextual fear. Given that hippocampal structural plasticity is proposed to provide a substrate for the storage of long-term memories, the main aim of this study is to evaluate the modulation of GABA neurotransmission in the BLA on spine density in the DH following stress on contextual fear learning. The present findings show that prior stressful experience promoted contextual fear memory and enhanced spine density in the DH. Intra-BLA infusion of midazolam, a positive modulator of GABAa sites, prevented the facilitating influence of stress on both fear retention and hippocampal dendritic spine remodeling. Similarly to the stress-induced effects, the blockade of GABAa sites within the BLA ameliorated fear memory emergence and induced structural remodeling in the DH. These findings suggest that GABAergic transmission in BLA modulates the structural changes in DH associated to the influence of stress on fear memory. © 2015 Wiley Periodicals, Inc.

  16. Olfaction, Emtion & the Amygdala: arousal-dependent modulation of long-term autobiographical memory and its association with olfaction

    Mark Hughes

    2004-01-01

    Full Text Available The sense of smell is set apart from other sensory modalities. Odours possess the capacity to trigger immediately strong emotional memories. Moreover, odorous stimuli provide a higher degree of memory retention than other sensory stimuli. Odour perception, even in its most elemental form - olfaction - already involves limbic structures. This early involvement is not paralleled in other sensory modalities. Bearing in mind the considerable connectivity with limbic structures, and the fact that an activation of the amygdala is capable of instantaneously evoking emotions and facilitating the encoding of memories, it is unsurprising that the sense of smell has its characteristic nature. The aim of this review is to analyse current understanding of higher olfactory information processing as it relates to the ability of odours to spontaneously cue highly vivid, affectively toned, and often very old autobiographical memories (episodes known anecdotally as Proust phenomena. Particular emphasis is placed on the diversity of functions attributed to the amygdala. Its role in modulating the encoding and retrieval of long-term memory is investigated with reference to lesion, electrophysiological, immediate early gene, and functional imaging studies in both rodents and humans. Additionally, the influence of hormonal modulation and the adrenergic system on emotional memory storage is outlined. I finish by proposing a schematic of some of the critical neural pathways that underlie the odour-associated encoding and retrieval of emotionally toned autobiographical memories.

  17. Modulation of visual cortical excitability by working memory: effect of luminance contrast of mental imagery

    Zaira eCattaneo

    2011-02-01

    Full Text Available Although much is known about the impact of stimulus properties such as luminance contrast, spatial frequency and orientation on visually evoked neural activity, much less is known about how they modulate neural activity when they are properties of a mental image held in working memory (WM. Here we addressed this question by investigating how a parametric manipulation of an imagined stimulus attribute affects neuronal excitability in the early visual cortex. We manipulated luminance contrast, a stimulus property known to strongly affect the magnitude of neuronal responses in early visual areas. Luminance contrast modulated neuronal excitability, as assessed by the frequency of phosphenes induced by transcranial magnetic stimulation (TMS with the exact nature of this modulation depending on TMS intensity. These results point to a strong overlap in the neuronal processes underlying visual perception and mental imagery: not only does WM maintenance selectively engage neurons which are tuned to the maintained attribute (as has previously been shown, but the extent to which those neurons are activated depends on the luminance contrast (as is the case with visually-evoked responses. From a methodological viewpoint, these results suggest that assessment of visual cortical excitability using TMS is affected by the TMS intensity used to probe the neuronal population.

  18. A Survey of Soft-Error Mitigation Techniques for Non-Volatile Memories

    Sparsh Mittal

    2017-02-01

    Full Text Available Non-volatile memories (NVMs offer superior density and energy characteristics compared to the conventional memories; however, NVMs suffer from severe reliability issues that can easily eclipse their energy efficiency advantages. In this paper, we survey architectural techniques for improving the soft-error reliability of NVMs, specifically PCM (phase change memory and STT-RAM (spin transfer torque RAM. We focus on soft-errors, such as resistance drift and write disturbance, in PCM and read disturbance and write failures in STT-RAM. By classifying the research works based on key parameters, we highlight their similarities and distinctions. We hope that this survey will underline the crucial importance of addressing NVM reliability for ensuring their system integration and will be useful for researchers, computer architects and processor designers.

  19. Reversal of cycloheximide-induced memory disruption by AIT-082 (Neotrofin) is modulated by, but not dependent on, adrenal hormones.

    Yan, Rongzi; Nguyen, Quang; Gonzaga, James; Johnson, Mai; Ritzmann, Ronald F; Taylor, Eve M

    2003-04-01

    AIT-082 (Neotrofin), a hypoxanthine derivative, has been shown to improve memory in both animals and humans. In animals, adrenal hormones modulate the efficacy of many memory-enhancing compounds, including piracetam and tacrine (Cognex). To investigate the role of adrenal hormones in the memory-enhancing action of AIT-082. Plasma levels of adrenal hormones (corticosterone and aldosterone) in mice were significantly reduced by surgical or chemical (aminoglutethimide) adrenalectomy or significantly elevated by oral administration of corticosterone. The effects of these hormone level manipulations on the memory-enhancing activity of AIT-082 and piracetam were evaluated using a cycloheximide-induced amnesia/passive avoidance model. As previously reported by others, the memory enhancing action of piracetam was abolished by adrenalectomy. In contrast, the memory enhancement by 60 mg/kg AIT-082 (IP) was unaffected. However, a sub-threshold dose of AIT-082 (0.1 mg/kg, IP) that did not improve memory in control animals did improve memory in adrenalectomized animals. These data suggested that, similar to piracetam and tacrine, the memory enhancing action of AIT-082 might be inhibited by high levels of adrenal hormones. As expected, corticosterone (30 and 100 mg/kg) inhibited the action of piracetam, however no dose up to 100 mg/kg corticosterone inhibited the activity of AIT-082. These data suggest that while AIT-082 function is not dependent on adrenal hormones, it is modulated by them. That memory enhancement by AIT-082 was not inhibited by high plasma corticosterone levels may have positive implications for its clinical utility, given that many Alzheimer's disease patients have elevated plasma cortisol levels.

  20. Memory

    ... it has to decide what is worth remembering. Memory is the process of storing and then remembering this information. There are different types of memory. Short-term memory stores information for a few ...

  1. Boosting the FM-Index on the GPU: Effective Techniques to Mitigate Random Memory Access.

    Chacón, Alejandro; Marco-Sola, Santiago; Espinosa, Antonio; Ribeca, Paolo; Moure, Juan Carlos

    2015-01-01

    The recent advent of high-throughput sequencing machines producing big amounts of short reads has boosted the interest in efficient string searching techniques. As of today, many mainstream sequence alignment software tools rely on a special data structure, called the FM-index, which allows for fast exact searches in large genomic references. However, such searches translate into a pseudo-random memory access pattern, thus making memory access the limiting factor of all computation-efficient implementations, both on CPUs and GPUs. Here, we show that several strategies can be put in place to remove the memory bottleneck on the GPU: more compact indexes can be implemented by having more threads work cooperatively on larger memory blocks, and a k-step FM-index can be used to further reduce the number of memory accesses. The combination of those and other optimisations yields an implementation that is able to process about two Gbases of queries per second on our test platform, being about 8 × faster than a comparable multi-core CPU version, and about 3 × to 5 × faster than the FM-index implementation on the GPU provided by the recently announced Nvidia NVBIO bioinformatics library.

  2. Influence of anesthesia techniques of caesarean section on memory, perception and speech

    Volkov O.O.

    2014-06-01

    Full Text Available In obstetrics postoperative cognitive dysfunctions may take place after caesarean section and vaginal delivery with poor results both for mother and child. The goal was to study influence of anesthesia techniques following caesarian section on memory, perception and speech. Having agreed with local ethics committee and obtained informed consent depending on anesthesia method, pregnant women were divided into 2 groups: 1st group (n=31 had spinal anesthesia, 2nd group (n=34 – total intravenous anesthesia. Spinal anesthesia: 1.8-2.2 mLs of hyperbaric 0.5% bupivacaine. ТIVА: Thiopental sodium (4 mgs kg-1, succinylcholine (1-1.5 mgs kg-1. Phentanyl (10-5-3 µgs kg-1 hour and Diazepam (10 mgs were used after newborn extraction. We used Luria’s test for memory assessment, perception was studied by test “recognition of time”. Speech was studied by test "name of fingers". Control points: 1 - before the surgery, 2 - in 24h after the caesarian section, 3 - on day 3 after surgery, 4 - at discharge from hospital (5-7th day. The study showed that initially decreased memory level in expectant mothers regressed along with the time after caesarean section. Memory is restored in 3 days after surgery regardless of anesthesia techniques. In spinal anesthesia on 5-7th postoperative day memory level exceeds that of used in total intravenous anesthesia. The perception and speech do not depend on the term of postoperative period. Anesthesia technique does not influence perception and speech restoration after caesarean sections.

  3. Field-In-Field Technique With Intrafractionally Modulated Junction Shifts for Craniospinal Irradiation

    Yom, Sue S.; Frija, Erik K. C.; Mahajan, Anita; Chang, Eric; Klein, Kelli C.; Shiu, Almon; Ohrt, Jared; Woo, Shiao

    2007-01-01

    Purpose: To plan craniospinal irradiation with 'field-in-field' (FIF) homogenization in combination with daily, intrafractional modulation of the field junctions, to minimize the possibility of spinal cord overdose. Methods and Materials: Lateral cranial fields and posterior spinal fields were planned using a forward-planned, step-and-shoot FIF technique. Field junctions were automatically modulated and custom-weighted for maximal homogeneity within each treatment fraction. Dose-volume histogram analyses and film dosimetry were used to assess results. Results: Plan inhomogeneity improved with FIF. Planning with daily modulated junction shifts provided consistent dose delivery during each fraction of treatment across the junctions. Modulation minimized the impact of a 5-mm setup error at the junction. Film dosimetry confirmed that no point in the junction exceeded the anticipated dose. Conclusions: Field-in-field planning and modulated junction shifts improve the homogeneity and consistency of daily dose delivery, simplify treatment, and reduce the impact of setup errors

  4. A Novel Analog-to-digital conversion Technique using nonlinear duty-cycle modulation

    Jean Mbihi; François Ndjali Beng; Martin Kom; Léandre Nneme Nneme

    2012-01-01

    A new type of analog-to-digital conversion technique is presented in this paper. The interfacing hardware is a very simple nonlinear circuit with 1-bit modulated output. As a implication, behind the hardware simplicity retained is hidden a dreadful nonlinear duty-cycle modulation ratio. However, the overall nonlinear behavior embeds a sufficiently wide linear range, for a rigorous digital reconstitution of the analog input signal using a standard linear filter. Simulation and experimental r...

  5. Motivation enhances visual working memory capacity through the modulation of central cognitive processes.

    Sanada, Motoyuki; Ikeda, Koki; Kimura, Kenta; Hasegawa, Toshikazu

    2013-09-01

    Motivation is well known to enhance working memory (WM) capacity, but the mechanism underlying this effect remains unclear. The WM process can be divided into encoding, maintenance, and retrieval, and in a change detection visual WM paradigm, the encoding and retrieval processes can be subdivided into perceptual and central processing. To clarify which of these segments are most influenced by motivation, we measured ERPs in a change detection task with differential monetary rewards. The results showed that the enhancement of WM capacity under high motivation was accompanied by modulations of late central components but not those reflecting attentional control on perceptual inputs across all stages of WM. We conclude that the "state-dependent" shift of motivation impacted the central, rather than the perceptual functions in order to achieve better behavioral performances. Copyright © 2013 Society for Psychophysiological Research.

  6. Noise reduction techniques used on the high power klystron modulators at Argonne National Laboratory

    Russell, T.J.

    1993-01-01

    The modulators used in the Advanced Photon Source at Argonne National Laboratory have been redesigned with an emphasis on electrical noise reduction. Since the modulators are 100 MW modulators with <700 ns rise time, electrical noise can be coupled very easily to other electronic equipment in the area. This paper will detail the efforts made to reduce noise coupled to surrounding equipment. Shielding and sound grounding techniques accomplished the goal of drastically reducing the noise induced in surrounding equipment. The approach used in grounding and shielding will be discussed, and data will be presented comparing earlier designs to the improved design

  7. Modulation of alpha and gamma oscillations related to retrospectively orienting attention within working memory.

    Poch, Claudia; Campo, Pablo; Barnes, Gareth R

    2014-07-01

    Selective attention mechanisms allow us to focus on information that is relevant to the current behavior and, equally important, ignore irrelevant information. An influential model proposes that oscillatory neural activity in the alpha band serves as an active functional inhibitory mechanism. Recent studies have shown that, in the same way that attention can be selectively oriented to bias sensory processing in favor of relevant stimuli in perceptual tasks, it is also possible to retrospectively orient attention to internal representations held in working memory. However, these studies have not explored the associated oscillatory phenomena. In the current study, we analysed the patterns of neural oscillatory activity recorded with magnetoencephalography while participants performed a change detection task, in which a spatial retro-cue was presented during the maintenance period, indicating which item or items were relevant for subsequent retrieval. Participants benefited from retro-cues in terms of accuracy and reaction time. Retro-cues also modulated oscillatory activity in the alpha and gamma frequency bands. We observed greater alpha activity in a ventral visual region ipsilateral to the attended hemifield, thus supporting its suppressive role, i.e., a functional disengagement of task-irrelevant regions. Accompanying this modulation, we found an increase in gamma activity contralateral to the attended hemifield, which could reflect attentional orienting and selective processing. These findings suggest that the oscillatory mechanisms underlying attentional orienting to representations held in working memory are similar to those engaged when attention is oriented in the perceptual space. © 2014 The Authors. European Journal of Neuroscience published by Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

  8. Serotonergic modulation of spatial working memory: predictions from a computational network model

    Maria eCano-Colino

    2013-09-01

    Full Text Available Serotonin (5-HT receptors of types 1A and 2A are massively expressed in prefrontal cortex (PFC neurons, an area associated with cognitive function. Hence, 5-HT could be effective in modulating prefrontal-dependent cognitive functions, such as spatial working memory (SWM. However, a direct association between 5-HT and SWM has proved elusive in psycho-pharmacological studies. Recently, a computational network model of the PFC microcircuit was used to explore the relationship between 5‑HT and SWM (Cano-Colino et al. 2013. This study found that both excessive and insufficient 5-HT levels lead to impaired SWM performance in the network, and it concluded that analyzing behavioral responses based on confidence reports could facilitate the experimental identification of SWM behavioral effects of 5‑HT neuromodulation. Such analyses may have confounds based on our limited understanding of metacognitive processes. Here, we extend these results by deriving three additional predictions from the model that do not rely on confidence reports. Firstly, only excessive levels of 5-HT should result in SWM deficits that increase with delay duration. Secondly, excessive 5-HT baseline concentration makes the network vulnerable to distractors at distances that were robust to distraction in control conditions, while the network still ignores distractors efficiently for low 5‑HT levels that impair SWM. Finally, 5-HT modulates neuronal memory fields in neurophysiological experiments: Neurons should be better tuned to the cued stimulus than to the behavioral report for excessive 5-HT levels, while the reverse should happen for low 5-HT concentrations. In all our simulations agonists of 5-HT1A receptors and antagonists of 5-HT2A receptors produced behavioral and physiological effects in line with global 5-HT level increases. Our model makes specific predictions to be tested experimentally and advance our understanding of the neural basis of SWM and its neuromodulation

  9. Modulation of working memory function by motivation through loss-aversion.

    Krawczyk, Daniel C; D'Esposito, Mark

    2013-04-01

    Cognitive performance is affected by motivation. Few studies, however, have investigated the neural mechanisms of the influence of motivation through potential monetary punishment on working memory. We employed functional MRI during a delayed recognition task that manipulated top-down control demands with added monetary incentives to some trials in the form of potential losses of bonus money. Behavioral performance on the task was influenced by loss-threatening incentives in the form of faster and more accurate performance. As shown previously, we found enhancement of activity for relevant stimuli occurs throughout all task periods (e.g., stimulus encoding, maintenance, and response) in both prefrontal and visual association cortex. Further, these activation patterns were enhanced for trials with possible monetary loss relative to nonincentive trials. During the incentive cue, the amygdala and striatum showed significantly greater activation when money was at a possible loss on the trial. We also evaluated patterns of functional connectivity between regions responsive to monetary consequences and prefrontal areas responsive to the task. This analysis revealed greater delay period connectivity between and the left insula and prefrontal cortex with possible monetary loss relative to nonincentive trials. Overall, these results reveal that incentive motivation can modulate performance on working memory tasks through top-down signals via amplification of activity within prefrontal and visual association regions selective to processing the perceptual inputs of the stimuli to be remembered. Copyright © 2011 Wiley Periodicals, Inc.

  10. Working Memory Modulation of Frontoparietal Network Connectivity in First-Episode Schizophrenia

    Nielsen, Jesper Duemose; Madsen, Kristoffer Hougaard; Wang, Zheng

    2017-01-01

    Working memory (WM) impairment is regarded as a core aspect of schizophrenia. However, the neural mechanisms behind this cognitive deficit remain unclear. The connectivity of a frontoparietal network is known to be important for subserving WM. Using functional magnetic resonance imaging, the curr......Working memory (WM) impairment is regarded as a core aspect of schizophrenia. However, the neural mechanisms behind this cognitive deficit remain unclear. The connectivity of a frontoparietal network is known to be important for subserving WM. Using functional magnetic resonance imaging......, the current study investigated whether WM-dependent modulation of effective connectivity in this network is affected in a group of first-episode schizophrenia (FES) patients compared with similarly performing healthy participants during a verbal n-back task. Dynamic causal modeling (DCM) of the coupling...... between regions (left inferior frontal gyrus (IFG), left inferior parietal lobe (IPL), and primary visual area) identified in a psychophysiological interaction (PPI) analysis was performed to characterize effective connectivity during the n-back task. The PPI analysis revealed that the connectivity...

  11. Epinephrine and glucose modulate training-related CREB phosphorylation in old rats: relationships to age-related memory impairments.

    Morris, Ken A; Gold, Paul E

    2013-02-01

    Epinephrine enhances memory in young adult rats, in part, by increasing blood glucose levels needed to modulate memory. In old rats, epinephrine is deficient at raising blood glucose levels and thus is only moderately effective at enhancing memory. In contrast, systemic glucose injections improve memory in old rats, with resulting memory performance equal to that of young rats. The diminished response of glucose to training in old rats may blunt downstream neurochemical and molecular mechanisms needed to upregulate memory processes. In the first experiment, young adult and old rats were trained on an inhibitory avoidance task with immediate post-training injections of aCSF or glucose into the dorsal hippocampus. Old rats had significant memory impairments compared to young rats 7 days after training. Intrahippocampal injections of glucose reversed age-related deficits, improving memory scores in old rats to values seen in young rats. A second experiment examined age-related changes in activation of the transcription factor CREB, which is widely implicated in memory formation and may act downstream of hormonal and metabolic signals. Activation was assessed in response to training with systemic injections of epinephrine and glucose at doses known to enhance memory. Young adult and old rats were trained on inhibitory avoidance with immediate post-training systemic injections of saline, epinephrine, or glucose. After training, old rats had significant impairments in CREB phosphorylation in area CA1 and the dentate gyrus region of the hippocampus, and in the basolateral and lateral amygdala. Epinephrine and glucose attenuated age-related deficits in CREB phosphorylation, but were more effective in the amygdala and hippocampus, respectively. Together, these results support the view that age-related changes in blood glucose responses to epinephrine contribute to memory impairments, which may be related to alterations in regional patterns of CREB phosphorylation. Copyright

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

    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…

  13. Visual working memory modulates low-level saccade target selection: Evidence from rapidly generated saccades in the global effect paradigm

    Hollingworth, Andrew; Matsukura, Michi; Luck, Steven J.

    2013-01-01

    In three experiments, we examined the influence of visual working memory (VWM) on the metrics of saccade landing position in a global effect paradigm. Participants executed a saccade to the more eccentric object in an object pair appearing on the horizontal midline, to the left or right of central fixation. While completing the saccade task, participants maintained a color in VWM for an unrelated memory task. Either the color of the saccade target matched the memory color (target match), the color of the distractor matched the memory color (distractor match), or the colors of neither object matched the memory color (no match). In the no-match condition, saccades tended to land at the midpoint between the two objects: the global, or averaging, effect. However, when one of the two objects matched VWM, the distribution of landing position shifted toward the matching object, both for target match and for distractor match. VWM modulation of landing position was observed even for the fastest quartile of saccades, with a mean latency as low as 112 ms. Effects of VWM on such rapidly generated saccades, with latencies in the express-saccade range, indicate that VWM interacts with the initial sweep of visual sensory processing, modulating perceptual input to oculomotor systems and thereby biasing oculomotor selection. As a result, differences in memory match produce effects on landing position similar to the effects generated by differences in physical salience. PMID:24190909

  14. Visual working memory modulates low-level saccade target selection: evidence from rapidly generated saccades in the global effect paradigm.

    Hollingworth, Andrew; Matsukura, Michi; Luck, Steven J

    2013-11-04

    In three experiments, we examined the influence of visual working memory (VWM) on the metrics of saccade landing position in a global effect paradigm. Participants executed a saccade to the more eccentric object in an object pair appearing on the horizontal midline, to the left or right of central fixation. While completing the saccade task, participants maintained a color in VWM for an unrelated memory task. Either the color of the saccade target matched the memory color (target match), the color of the distractor matched the memory color (distractor match), or the colors of neither object matched the memory color (no match). In the no-match condition, saccades tended to land at the midpoint between the two objects: the global, or averaging, effect. However, when one of the two objects matched VWM, the distribution of landing position shifted toward the matching object, both for target match and for distractor match. VWM modulation of landing position was observed even for the fastest quartile of saccades, with a mean latency as low as 112 ms. Effects of VWM on such rapidly generated saccades, with latencies in the express-saccade range, indicate that VWM interacts with the initial sweep of visual sensory processing, modulating perceptual input to oculomotor systems and thereby biasing oculomotor selection. As a result, differences in memory match produce effects on landing position similar to the effects generated by differences in physical salience.

  15. Modulating the Focus of Attention for Spoken Words at Encoding Affects Frontoparietal Activation for Incidental Verbal Memory

    Thomas A. Christensen

    2012-01-01

    Full Text Available Attention is crucial for encoding information into memory, and current dual-process models seek to explain the roles of attention in both recollection memory and incidental-perceptual memory processes. The present study combined an incidental memory paradigm with event-related functional MRI to examine the effect of attention at encoding on the subsequent neural activation associated with unintended perceptual memory for spoken words. At encoding, we systematically varied attention levels as listeners heard a list of single English nouns. We then presented these words again in the context of a recognition task and assessed the effect of modulating attention at encoding on the BOLD responses to words that were either attended strongly, weakly, or not heard previously. MRI revealed activity in right-lateralized inferior parietal and prefrontal regions, and positive BOLD signals varied with the relative level of attention present at encoding. Temporal analysis of hemodynamic responses further showed that the time course of BOLD activity was modulated differentially by unintentionally encoded words compared to novel items. Our findings largely support current models of memory consolidation and retrieval, but they also provide fresh evidence for hemispheric differences and functional subdivisions in right frontoparietal attention networks that help shape auditory episodic recall.

  16. Modulating the focus of attention for spoken words at encoding affects frontoparietal activation for incidental verbal memory.

    Christensen, Thomas A; Almryde, Kyle R; Fidler, Lesley J; Lockwood, Julie L; Antonucci, Sharon M; Plante, Elena

    2012-01-01

    Attention is crucial for encoding information into memory, and current dual-process models seek to explain the roles of attention in both recollection memory and incidental-perceptual memory processes. The present study combined an incidental memory paradigm with event-related functional MRI to examine the effect of attention at encoding on the subsequent neural activation associated with unintended perceptual memory for spoken words. At encoding, we systematically varied attention levels as listeners heard a list of single English nouns. We then presented these words again in the context of a recognition task and assessed the effect of modulating attention at encoding on the BOLD responses to words that were either attended strongly, weakly, or not heard previously. MRI revealed activity in right-lateralized inferior parietal and prefrontal regions, and positive BOLD signals varied with the relative level of attention present at encoding. Temporal analysis of hemodynamic responses further showed that the time course of BOLD activity was modulated differentially by unintentionally encoded words compared to novel items. Our findings largely support current models of memory consolidation and retrieval, but they also provide fresh evidence for hemispheric differences and functional subdivisions in right frontoparietal attention networks that help shape auditory episodic recall.

  17. Radiation doses during chest examinations using dose modulation techniques in multislice CT scanner

    Livingstone Roshan; Pradip Joe; Dinakran Paul; Srikanth B

    2010-01-01

    Objective: To evaluate the radiation dose and image quality using a manual protocol and dose modulation techniques in a 6-slice CT scanner. Materials and Methods: Two hundred and twenty-one patients who underwent contrast-enhanced CT of the chest were included in the study. For the manual protocol settings, constant tube potential (kV) and tube current-time product (mAs) of 140 kV and 120 mAs, respectively, were used. The angular and z-axis dose modulation techniques utilized a constant tu...

  18. The hippocampus as a "stupid," domain-specific module: Implications for theories of recent and remote memory, and of imagination.

    Moscovitch, Morris

    2008-03-01

    The hippocampus and surrounding regions of the medial temporal lobe play a central role in all neuropsychological theories of memory. It is still a matter of debate, however, how best to characterise the functions of these regions, the hippocampus in particular. In this article, I examine the proposal that the hippocampus is a "stupid" module whose specific domain is consciously apprehended information. A number of interesting consequences for the organisation of memory and the brain follow from this proposal and the assumptions it entails. These, in turn, have important implications for neuropsychological theories of recent and remote episodic, semantic, and spatial memory and for the functions that episodic memory may serve in perception, comprehension, planning, imagination, and problem solving. I consider these implications by selectively reviewing the literature and primarily drawing on research my collaborators and I have conducted. Copyright (c) 2008 APA, all rights reserved.

  19. Development of a CMOS time memory cell VLSI and CAMAC module with 0.5 ns resolution

    Arai, Y.; Ikeno, M.; Matsumura, T.

    1992-01-01

    A CMOS time-to-digital converter chip, the Time Memory Cell (TMC), for high-rate wire chamber application has been developed. The chip has a timing resolution of 0.52 ns, dissipates only 7 mW/channel, and contains 4 channels in a chip. Each channel has 1024 memory locations which act as a buffer 1μs deep. The chip was fabricated in a 0.8 μm CMOS process and is 5.0 mm by 5.6 mm. Using the TMC chip, a CAMAC module with 32 input channels was developed. This module is designed to operate in both 'Common Start' and 'Common Stop' modes. The circuit of the module and test results are described in this paper

  20. GABAergic modulation of visual gamma and alpha oscillations and its consequences for working memory performance.

    Lozano-Soldevilla, Diego; ter Huurne, Niels; Cools, Roshan; Jensen, Ole

    2014-12-15

    Impressive in vitro research in rodents and computational modeling has uncovered the core mechanisms responsible for generating neuronal oscillations. In particular, GABAergic interneurons play a crucial role for synchronizing neural populations. Do these mechanistic principles apply to human oscillations associated with function? To address this, we recorded ongoing brain activity using magnetoencephalography (MEG) in healthy human subjects participating in a double-blind pharmacological study receiving placebo, 0.5 mg and 1.5 mg of lorazepam (LZP; a benzodiazepine upregulating GABAergic conductance). Participants performed a demanding visuospatial working memory (WM) task. We found that occipital gamma power associated with WM recognition increased with LZP dosage. Importantly, the frequency of the gamma activity decreased with dosage, as predicted by models derived from the rat hippocampus. A regionally specific gamma increase correlated with the drug-related performance decrease. Despite the system-wide pharmacological intervention, gamma power drug modulations were specific to visual cortex: sensorimotor gamma power and frequency during button presses remained unaffected. In contrast, occipital alpha power modulations during the delay interval decreased parametrically with drug dosage, predicting performance impairment. Consistent with alpha oscillations reflecting functional inhibition, LZP affected alpha power strongly in early visual regions not required for the task demonstrating a regional specific occipital impairment. GABAergic interneurons are strongly implicated in the generation of gamma and alpha oscillations in human occipital cortex where drug-induced power modulations predicted WM performance. Our findings bring us an important step closer to linking neuronal dynamics to behavior by embracing established animal models. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Development of the MCM-D technique for pixel detector modules

    Grah, C.

    2005-03-01

    This thesis treats a copper--polymer based thin film technology, the MCM-D technique and its application when building hybrid pixel detector modules. The ATLAS experiment at the LHC will be equipped with a pixel detector system. The basic mechanical units of the pixel detector are multi chip modules. The main components of these modules are: 16 electronic chips, a controller chip and a large sensor tile, featuring more than 46000 sensor cells. MCM-D is a superior technique to build the necessary signal bus system and the power distribution system directly on the active sensor tile. In collaboration with the Fraunhofer Institute for Reliability and Microintegration, IZM, the thin film process is reviewed and enhanced. The multi layer system was designed and optimized for the interconnection system as well as for the 46000 pixel contacts. Laboratory measurements on prototypes prove that complex routing schemes for geometrically optimized single chips are suitable and have negligible influence on the front--end chips performance. A full scale MCM-D module has been built and it is shown that the technology is suitable to build pixel detector modules. Further tests include the investigation of the impact of hadronic irradiation on the thin film layers. Single chip assemblies have been operated in a test beam environment and the feasibility of the optimization of the sensors could be shown. A review on the potential as well as the perspective for the MCM-D technique in future experiments is given

  2. Advanced intensity-modulation continuous-wave lidar techniques for ASCENDS CO2 column measurements

    Campbell, Joel F.; Lin, Bing; Nehrir, Amin R.; Harrison, F. W.; Obland, Michael D.; Meadows, Byron

    2015-10-01

    Global atmospheric carbon dioxide (CO2) measurements for the NASA Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) space mission are critical for improving our understanding of global CO2 sources and sinks. Advanced Intensity- Modulated Continuous-Wave (IM-CW) lidar techniques are investigated as a means of facilitating CO2 measurements from space to meet the ASCENDS measurement requirements. In recent numerical, laboratory and flight experiments we have successfully used the Binary Phase Shift Keying (BPSK) modulation technique to uniquely discriminate surface lidar returns from intermediate aerosol and cloud contamination. We demonstrate the utility of BPSK to eliminate sidelobes in the range profile as a means of making Integrated Path Differential Absorption (IPDA) column CO2 measurements in the presence of optically thin clouds, thereby eliminating the need to correct for sidelobe bias errors caused by the clouds. Furthermore, high accuracy and precision ranging to the surface as well as to the top of intermediate cloud layers, which is a requirement for the inversion of column CO2 number density measurements to column CO2 mixing ratios, has been demonstrated using new hyperfine interpolation techniques that takes advantage of the periodicity of the modulation waveforms. This approach works well for both BPSK and linear swept-frequency modulation techniques. The BPSK technique under investigation has excellent auto-correlation properties while possessing a finite bandwidth. A comparison of BPSK and linear swept-frequency is also discussed in this paper. These results are extended to include Richardson-Lucy deconvolution techniques to extend the resolution of the lidar beyond that implied by limit of the bandwidth of the modulation, where it is shown useful for making tree canopy measurements.

  3. Advanced Intensity-Modulation Continuous-Wave Lidar Techniques for ASCENDS O2 Column Measurements

    Campbell, Joel F.; Lin, Bing; Nehrir, Amin R.; Harrison, F. Wallace; Obland, Michael D.; Meadows, Byron

    2015-01-01

    Global atmospheric carbon dioxide (CO2) measurements for the NASA Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) space mission are critical for improving our understanding of global CO2 sources and sinks. Advanced Intensity- Modulated Continuous-Wave (IM-CW) lidar techniques are investigated as a means of facilitating CO2 measurements from space to meet the ASCENDS measurement requirements. In recent numerical, laboratory and flight experiments we have successfully used the Binary Phase Shift Keying (BPSK) modulation technique to uniquely discriminate surface lidar returns from intermediate aerosol and cloud contamination. We demonstrate the utility of BPSK to eliminate sidelobes in the range profile as a means of making Integrated Path Differential Absorption (IPDA) column CO2 measurements in the presence of optically thin clouds, thereby eliminating the need to correct for sidelobe bias errors caused by the clouds. Furthermore, high accuracy and precision ranging to the surface as well as to the top of intermediate cloud layers, which is a requirement for the inversion of column CO2 number density measurements to column CO2 mixing ratios, has been demonstrated using new hyperfine interpolation techniques that takes advantage of the periodicity of the modulation waveforms. This approach works well for both BPSK and linear swept-frequency modulation techniques. The BPSK technique under investigation has excellent auto-correlation properties while possessing a finite bandwidth. A comparison of BPSK and linear swept-frequency is also discussed in this paper. These results are extended to include Richardson-Lucy deconvolution techniques to extend the resolution of the lidar beyond that implied by limit of the bandwidth of the modulation, where it is shown useful for making tree canopy measurements.

  4. Testing remotely operated module technique for Wackersdorf reprocessing plant at Lahde test rig

    Leister, P.; Schroeder, G.; Boehme, G.

    1986-01-01

    The FEMO technique represents a plant concept which makes it possible to carry out the repair of high and medium activity wet chemical stages of the process by remote handling without direct access by staff. For this purpose, the apparatus of this step of the process is arranged modularly in large cells, so that movable large handling devices such as cranes and manipulator systems can replace process components subject to wear via the process modules. The machine room of the former coal-fired power station Heyden I at Lahde was, after removal of the turbines and generators, converted to a hall in which the following test areas were accommodated: FEMO cell section with 10 positions for module, cell wall mock-up and wall penetration, module mounting area, module measuring position, workplace for service area, training position, welding position and FEMO control position. (orig./HP) [de

  5. Optimal time-domain technique for pulse width modulation in power electronics

    I. Mayergoyz

    2018-05-01

    Full Text Available Optimal time-domain technique for pulse width modulation is presented. It is based on exact and explicit analytical solutions for inverter circuits, obtained for any sequence of input voltage rectangular pulses. Two optimal criteria are discussed and illustrated by numerical examples.

  6. Dosimetric comparison of field in field intensity-modulated radiotherapy technique with conformal radiotherapy techniques in breast cancer

    Ercan, T.; Alco, G.; Zengin, F.; Atilla, S.; Dincer, M.; Igdem, S.; Okkan, S.

    2010-01-01

    The aim of this study was to be able to implement the field-in-field intensity-modulated radiotherapy (FiF) technique in our daily practice for breast radiotherapy. To do this, we performed a dosimetric comparison. Treatment plans were produced for 20 consecutive patients. FiF plans and conformal radiotherapy (CRT) plans were compared for doses in the planning target volume (PTV), the dose homogeneity index (DHI), doses in irradiated soft tissue outside the target volume (SST), ipsilateral lung and heart doses for left breast irradiation, and the monitor unit counts (MU) required for treatment. Averaged values were compared using Student's t-test. With FiF, the DHI is improved 7.0% and 5.7%, respectively (P<0.0001) over the bilateral and lateral wedge CRT techniques. When the targeted volumes received 105% and 110% of the prescribed dose in the PTV were compared, significant decreases are found with the FiF technique. With the 105% dose, the SST, heart, and ipsilateral lung doses and the MU counts were also significantly lower with the FiF technique. The FiF technique, compared to CRT, for breast radiotherapy enables significantly better dose distribution in the PTV. Significant differences are also found for soft tissue volume, the ipsilateral lung dose, and the heart dose. Considering the decreased MUs needed for treatment, the FiF technique is preferred over tangential CRT. (author)

  7. Intensity Modulation Techniques for Continuous-Wave Lidar for Column CO2 Measurements

    Campbell, J. F.; Lin, B.; Obland, M. D.; Kooi, S. A.; Fan, T. F.; Meadows, B.; Browell, E. V.; Erxleben, W. H.; McGregor, D.; Dobler, J. T.; Pal, S.; O'Dell, C.

    2017-12-01

    Global and regional atmospheric carbon dioxide (CO2) measurements for the NASA Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) space mission and the Atmospheric Carbon and Transport (ACT) - America project are critical for improving our understanding of global CO2 sources and sinks. Advanced Intensity-Modulated Continuous-Wave (IM-CW) lidar techniques are investigated as a means of facilitating CO2 measurements from space and airborne platforms to meet the ASCENDS and ACT-America science measurement requirements. In recent numerical, laboratory and flight experiments we have successfully used the Binary Phase Shift Keying (BPSK) and Linear Swept Frequency modulations to uniquely discriminate surface lidar returns from intermediate aerosol and cloud returns. We demonstrate the utility of BPSK to eliminate sidelobes in the range profile as a means of making Integrated Path Differential Absorption (IPDA) column CO2 measurements in the presence of optically thin clouds, thereby eliminating bias errors caused by the clouds. Furthermore, high accuracy and precision ranging to the surface as well as to the top of intermediate cloud layers, which is a requirement for the inversion of column CO2 number density measurements to column CO2 mixing ratios, has been demonstrated using new hyperfine interpolation techniques that take advantage of the periodicity of the modulation waveforms. This approach works well for both BPSK and linear swept-frequency modulation techniques and provides very high (at sub-meter level) range resolution. We compare BPSK to linear swept frequency and introduce a new technique to eliminate sidelobes in situations from linear swept frequency where the SNR is high with results that rival BPSK. We also investigate the effects of non-linear modulators, which can in some circumstances degrade the orthogonality of the waveforms, and show how to avoid this. These techniques are used in a new data processing architecture written in

  8. Circadian modulation of consolidated memory retrieval following sleep deprivation in Drosophila.

    Le Glou, Eric; Seugnet, Laurent; Shaw, Paul J; Preat, Thomas; Goguel, Valérie

    2012-10-01

    Several lines of evidence indicate that sleep plays a critical role in learning and memory. The aim of this study was to evaluate anesthesia resistant memory following sleep deprivation in Drosophila. Four to 16 h after aversive olfactory training, flies were sleep deprived for 4 h. Memory was assessed 24 h after training. Training, sleep deprivation, and memory tests were performed at different times during the day to evaluate the importance of the time of day for memory formation. The role of circadian rhythms was further evaluated using circadian clock mutants. Memory was disrupted when flies were exposed to 4 h of sleep deprivation during the consolidation phase. Interestingly, normal memory was observed following sleep deprivation when the memory test was performed during the 2 h preceding lights-off, a period characterized by maximum wake in flies. We also show that anesthesia resistant memory was less sensitive to sleep deprivation in flies with disrupted circadian rhythms. Our results indicate that anesthesia resistant memory, a consolidated memory less costly than long-term memory, is sensitive to sleep deprivation. In addition, we provide evidence that circadian factors influence memory vulnerability to sleep deprivation and memory retrieval. Taken together, the data show that memories weakened by sleep deprivation can be retrieved if the animals are tested at the optimal circadian time.

  9. Diminishing-cues retrieval practice: A memory-enhancing technique that works when regular testing doesn't.

    Fiechter, Joshua L; Benjamin, Aaron S

    2017-08-28

    Retrieval practice has been shown to be a highly effective tool for enhancing memory, a fact that has led to major changes to educational practice and technology. However, when initial learning is poor, initial retrieval practice is unlikely to be successful and long-term benefits of retrieval practice are compromised or nonexistent. Here, we investigate the benefit of a scaffolded retrieval technique called diminishing-cues retrieval practice (Finley, Benjamin, Hays, Bjork, & Kornell, Journal of Memory and Language, 64, 289-298, 2011). Under learning conditions that favored a strong testing effect, diminishing cues and standard retrieval practice both enhanced memory performance relative to restudy. Critically, under learning conditions where standard retrieval practice was not helpful, diminishing cues enhanced memory performance substantially. These experiments demonstrate that diminishing-cues retrieval practice can widen the range of conditions under which testing can benefit memory, and so can serve as a model for the broader application of testing-based techniques for enhancing learning.

  10. Cortical activities of single-trial P300 amplitudes modulated by memory load using simultaneous EEG-fMRI

    Zhang, Qiushi; Zhao, Xiaojie; Zhu, Chaozhe; Yang, Xueqian; Yao, Li

    2015-03-01

    The functional magnetic resonance imaging (fMRI) researches on working memory have found that activation of cortical areas appeared dependent on memory load, and event-related potentials (ERP) studies have demonstrated that amplitudes of P300 decreased significantly when working memory load increased. However, the cortical activities related with P300 amplitudes under different memory loads remains unclear. Joint fMRI and EEG analysis which fusions the time and spatial information in simultaneous EEG-fMRI recording can reveal the regional activation at each ERP time point. In this paper, we first used wavelet transform to obtain the single-trial amplitudes of P300 caused by a digital N-back task in the simultaneous EEG-fMRI recording as the ERP feature sequences. Then the feature sequences in 1-back condition and 3-back condition were introduced into general linear model (GLM) separately as parametric modulations to compare the cortical activation under different memory loads. The results showed that the average amplitudes of P300 in 3-back significantly decreased than that in 1-back, and the activities induced by ERP feature sequences in 3-back also significantly decreased than that in the 1-back, including the insular, anterior cingulate cortex, right inferior frontal gyrus, and medial frontal gyrus, which were relevant to the storage, monitoring, and manipulation of information in working memory task. Moreover, the difference in the activation caused by ERP feature showed a positive correlation with the difference in behavioral performance. These findings demonstrated the locations of P300 amplitudes differences modulated by the memory load and its relationship with the behavioral performance.

  11. Measurement of the amplitude and phase transfer functions of an optical modulator using a heterodyne technique

    Romstad, Francis Pascal; Birkedal, Dan; Mørk, Jesper

    2001-01-01

    We present a new technique that measures the full amplitude and phase transfer curves of the modulator as a function of the applied bias, from which the small signal α-parameter can be calculated. The technique measures the amplitude and phase transfer functions simultaneously and directly......, compared to techniques where a time-consuming data analysis is necessary to calculate the a-parameter and an additional measurement is necessary to estimate the phase. Additionally, the chirp profile for all operation points can be calculated....

  12. Network module detection: Affinity search technique with the multi-node topological overlap measure.

    Li, Ai; Horvath, Steve

    2009-07-20

    Many clustering procedures only allow the user to input a pairwise dissimilarity or distance measure between objects. We propose a clustering method that can input a multi-point dissimilarity measure d(i1, i2, ..., iP) where the number of points P can be larger than 2. The work is motivated by gene network analysis where clusters correspond to modules of highly interconnected nodes. Here, we define modules as clusters of network nodes with high multi-node topological overlap. The topological overlap measure is a robust measure of interconnectedness which is based on shared network neighbors. In previous work, we have shown that the multi-node topological overlap measure yields biologically meaningful results when used as input of network neighborhood analysis. We adapt network neighborhood analysis for the use of module detection. We propose the Module Affinity Search Technique (MAST), which is a generalized version of the Cluster Affinity Search Technique (CAST). MAST can accommodate a multi-node dissimilarity measure. Clusters grow around user-defined or automatically chosen seeds (e.g. hub nodes). We propose both local and global cluster growth stopping rules. We use several simulations and a gene co-expression network application to argue that the MAST approach leads to biologically meaningful results. We compare MAST with hierarchical clustering and partitioning around medoid clustering. Our flexible module detection method is implemented in the MTOM software which can be downloaded from the following webpage: http://www.genetics.ucla.edu/labs/horvath/MTOM/

  13. Modulating effect of COMT Val(158)Met polymorphism on interference resolution during a working memory task.

    Jaspar, Mathieu; Dideberg, Vinciane; Bours, Vincent; Maquet, Pierre; Collette, Fabienne

    2015-04-01

    Genetic variability related to the catechol-O-methyltransferase (COMT) gene has received increasing attention in the last 15years, in particular as a potential modulator of the neural substrates underlying inhibitory processes and updating in working memory (WM). In an event-related functional magnetic resonance imaging (fMRI) study, we administered a modified version of the Sternberg probe recency task (Sternberg, 1966) to 43 young healthy volunteers, varying the level of interference across successive items. The task was divided into two parts (high vs. low interference) to induce either proactive or reactive control processes. The participants were separated into three groups according to their COMT Val(158)Met genotype [Val/Val (VV); Val/Met (VM); Met/Met (MM)]. The general aim of the study was to determine whether COMT polymorphism has a modulating effect on the neural substrates of interference resolution during WM processing. Results indicate that interfering trials were associated with greater involvement of frontal cortices (bilateral medial frontal gyrus, left precentral and superior frontal gyri, right inferior frontal gyrus) in VV homozygous subjects (by comparison to Met allele carriers) only in the proactive condition of the task. In addition, analysis of peristimulus haemodynamic responses (PSTH) revealed that the genotype-related difference observed in the left SFG was specifically driven by a larger increase in activity from the storage to the recognition phase of the interfering trials in VV homozygous subjects. These results confirm the impact of COMT genotype on inhibitory processes during a WM task, with an advantage for Met allele carriers. Interestingly, this impact on frontal areas is present only when the level of interference is high, and especially during the transition from storage to recognition in the left superior frontal gyrus. Copyright © 2015 Elsevier Inc. All rights reserved.

  14. Opposite monosynaptic scaling of BLP-vCA1 inputs governs hopefulness- and helplessness-modulated spatial learning and memory.

    Yang, Ying; Wang, Zhi-Hao; Jin, Sen; Gao, Di; Liu, Nan; Chen, Shan-Ping; Zhang, Sinan; Liu, Qing; Liu, Enjie; Wang, Xin; Liang, Xiao; Wei, Pengfei; Li, Xiaoguang; Li, Yin; Yue, Chenyu; Li, Hong-Lian; Wang, Ya-Li; Wang, Qun; Ke, Dan; Xie, Qingguo; Xu, Fuqiang; Wang, Liping; Wang, Jian-Zhi

    2016-07-14

    Different emotional states lead to distinct behavioural consequences even when faced with the same challenging events. Emotions affect learning and memory capacities, but the underlying neurobiological mechanisms remain elusive. Here we establish models of learned helplessness (LHL) and learned hopefulness (LHF) by exposing animals to inescapable foot shocks or with anticipated avoidance trainings. The LHF animals show spatial memory potentiation with excitatory monosynaptic upscaling between posterior basolateral amygdale (BLP) and ventral hippocampal CA1 (vCA1), whereas the LHL show memory deficits with an attenuated BLP-vCA1 connection. Optogenetic disruption of BLP-vCA1 inputs abolishes the effects of LHF and impairs synaptic plasticity. By contrast, targeted BLP-vCA1 stimulation rescues the LHL-induced memory deficits and mimics the effects of LHF. BLP-vCA1 stimulation increases synaptic transmission and dendritic plasticity with the upregulation of CREB and intrasynaptic AMPA receptors in CA1. These findings indicate that opposite excitatory monosynaptic scaling of BLP-vCA1 controls LHF- and LHL-modulated spatial memory, revealing circuit-specific mechanisms linking emotions to memory.

  15. Opposite monosynaptic scaling of BLP–vCA1 inputs governs hopefulness- and helplessness-modulated spatial learning and memory

    Yang, Ying; Wang, Zhi-Hao; Jin, Sen; Gao, Di; Liu, Nan; Chen, Shan-Ping; Zhang, Sinan; Liu, Qing; Liu, Enjie; Wang, Xin; Liang, Xiao; Wei, Pengfei; Li, Xiaoguang; Li, Yin; Yue, Chenyu; Li, Hong-lian; Wang, Ya-Li; Wang, Qun; Ke, Dan; Xie, Qingguo; Xu, Fuqiang; Wang, Liping; Wang, Jian-Zhi

    2016-01-01

    Different emotional states lead to distinct behavioural consequences even when faced with the same challenging events. Emotions affect learning and memory capacities, but the underlying neurobiological mechanisms remain elusive. Here we establish models of learned helplessness (LHL) and learned hopefulness (LHF) by exposing animals to inescapable foot shocks or with anticipated avoidance trainings. The LHF animals show spatial memory potentiation with excitatory monosynaptic upscaling between posterior basolateral amygdale (BLP) and ventral hippocampal CA1 (vCA1), whereas the LHL show memory deficits with an attenuated BLP–vCA1 connection. Optogenetic disruption of BLP–vCA1 inputs abolishes the effects of LHF and impairs synaptic plasticity. By contrast, targeted BLP–vCA1 stimulation rescues the LHL-induced memory deficits and mimics the effects of LHF. BLP–vCA1 stimulation increases synaptic transmission and dendritic plasticity with the upregulation of CREB and intrasynaptic AMPA receptors in CA1. These findings indicate that opposite excitatory monosynaptic scaling of BLP–vCA1 controls LHF- and LHL-modulated spatial memory, revealing circuit-specific mechanisms linking emotions to memory. PMID:27411738

  16. Hormonal modulation of novelty processing in women: Enhanced under working memory load with high dehydroepiandrosterone-sulfate-to-dehydroepiandrosterone ratios.

    do Vale, Sónia; Selinger, Lenka; Martins, João Martin; Bicho, Manuel; do Carmo, Isabel; Escera, Carles

    2016-11-10

    Several studies have suggested that dehydroepiandrosterone (DHEA) and dehydroepiandrosterone-sulfate (DHEAS) may enhance working memory and attention, yet current evidence is still inconclusive. The balance between both forms of the hormone might be crucial regarding the effects that DHEA and DHEAS exert on the central nervous system. To test the hypothesis that higher DHEAS-to-DHEA ratios might enhance working memory and/or involuntary attention, we studied the DHEAS-to-DHEA ratio in relation to involuntary attention and working memory processing by recording the electroencephalogram of 22 young women while performing a working memory load task and a task without working memory load in an audio-visual oddball paradigm. DHEA and DHEAS were measured in saliva before each task. We found that a higher DHEAS-to-DHEA ratio was related to enhanced auditory novelty-P3 amplitudes during performance of the working memory task, indicating an increased processing of the distracter, while on the other hand there was no difference in the processing of the visual target. These results suggest that the balance between DHEAS and DHEA levels modulates involuntary attention during the performance of a task with cognitive load without interfering with the processing of the task-relevant visual stimulus. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  17. Memory modulation across neural systems: intra-amygdala glucose reverses deficits caused by intraseptal morphine on a spatial task but not on an aversive task.

    McNay, E C; Gold, P E

    1998-05-15

    Based largely on dissociations of the effects of different lesions on learning and memory, memories for different attributes appear to be organized in independent neural systems. Results obtained with direct injections of drugs into one brain region at a time support a similar conclusion. The present experiments investigated the effects of simultaneous pharmacological manipulation of two neural systems, the amygdala and the septohippocampal system, to examine possible interactions of memory modulation across systems. Morphine injected into the medial septum impaired memory both for avoidance training and during spontaneous alternation. When glucose was concomitantly administered to the amygdala, glucose reversed the morphine-induced deficits in memory during alternation but not for avoidance training. These results suggest that the amygdala is involved in modulation of spatial memory processes and that direct injections of memory-modulating drugs into the amygdala do not always modulate memory for aversive events. These findings are contrary to predictions from the findings of lesion studies and of studies using direct injections of drugs into single brain areas. Thus, the independence of neural systems responsible for processing different classes of memory is less clear than implied by studies using lesions or injections of drugs into single brain areas.

  18. Are training and transfer effects of working memory updating training modulated by achievement motivation?

    Zhao, Xin; Xu, Yiwenjie; Fu, Junjun; Maes, Joseph H R

    2018-04-01

    Previous studies examining effects of working memory (WM) updating training revealed mixed results. One factor that might modulate training gains, and possibly also transfer of those gains to non-trained cognitive tasks, is achievement motivation. In the present Studies 1 and 2, students with either a high (HAM) or low (LAM) achievement motivation completed a 14-day visuospatial WM updating training program. In Study 2, the students also performed a set of tasks measuring other executive functions and fluid intelligence prior to and after training. In both studies, the HAM students displayed a larger training gain than the LAM students. Study 2 revealed that after training, both groups showed better performance on the near-transfer but not far-transfer tasks. Importantly, the differential training gain was not associated with better post-training performance for the HAM compared to the LAM students on any of the transfer tasks. These results are taken to support a modulatory role of achievement motivation on WM training benefits, but not on transfer of those benefits to other tasks. Possible reasons for the general improvement on the near-transfer tasks and the absence of a modulatory role of achievement motivation on transfer-task performance are discussed.

  19. Stroop proactive control and task conflict are modulated by concurrent working memory load.

    Kalanthroff, Eyal; Avnit, Amir; Henik, Avishai; Davelaar, Eddy J; Usher, Marius

    2015-06-01

    Performance on the Stroop task reflects two types of conflict-informational (between the incongruent word and font color) and task (between the contextually relevant color-naming task and the irrelevant, but automatic, word-reading task). According to the dual mechanisms of control theory (DMC; Braver, 2012), variability in Stroop performance can result from variability in the deployment of a proactive task-demand control mechanism. Previous research has shown that when proactive control (PC) is diminished, both increased Stroop interference and a reversed Stroop facilitation (RF) are observed. Although the current DMC model accounts for the former effect, it does not predict the observed RF, which is considered to be behavioral evidence for task conflict in the Stroop task. Here we expanded the DMC model to account for Stroop RF. Assuming that a concurrent working memory (WM) task reduces PC, we predicted both increased interference and an RF. Nineteen participants performed a standard Stroop task combined with a concurrent n-back task, which was aimed at reducing available WM resources, and thus overloading PC. Although the results indicated common Stroop interference and facilitation in the low-load condition (zero-back), in the high-load condition (two-back), both increased Stroop interference and RF were observed, consistent with the model's prediction. These findings indicate that PC is modulated by concurrent WM load and serves as a common control mechanism for both informational and task Stroop conflicts.

  20. A vacancy-modulated self-selective resistive switching memory with pronounced nonlinear behavior

    Ma, Haili; Feng, Jie; Gao, Tian; Zhu, Xi

    2017-12-01

    In this study, we report a self-selective (nonlinear) resistive switching memory cell, with high on-state half-bias nonlinearity of 650, sub-μA operating current, and high On/Off ratios above 100×. Regarding the cell structure, a thermal oxidized HfO x layer in combination with a sputtered Ta2O5 layer was configured as an active stack, with Pt and Hf as top and bottom electrodes, respectively. The Ta2O5 acts as a selective layer as well as a series resistor, which could make the resistive switching happened in HfO x layer. Through the analysis of the physicochemical properties and electrical conduction mechanisms at each state, a vacancy-modulated resistance switching model was proposed to explain the switching behavior. The conductivity of HfO x layer was changed by polarity-dependent drift of the oxygen vacancy ( V o), resulting in an electron hopping distance change during switching. With the help of Ta2O5 selective layer, high nonlinearity observed in low resistance state. The proposed material stack shows a promising prospect to act as a self-selective cell for 3D vertical RRAM application.

  1. Pulse width modulation-based temperature tracking for feedback control of a shape memory alloy actuator.

    Ayvali, Elif; Desai, Jaydev P

    2014-04-01

    This work presents a temperature-feedback approach to control the radius of curvature of an arc-shaped shape memory alloy (SMA) wire. The nonlinear properties of the SMA such as phase transformation and its dependence on temperature and stress make SMA actuators difficult to control. Tracking a desired trajectory is more challenging than controlling just the position of the SMA actuator since the desired path is continuously changing. Consequently, tracking the desired strain directly or tracking the parameters such as temperature and electrical resistance that are related to strain with a model is a challenging task. Temperature-feedback is an attractive approach when direct measurement of strain is not practical. Pulse width modulation (PWM) is an effective method for SMA actuation and it can be used along with a compensator to control the temperature of the SMA. Using the constitutive model of the SMA, the desired temperature profile can be obtained for a given strain trajectory. A PWM-based nonlinear PID controller with a feed-forward heat transfer model is proposed to use temperature-feedback for tracking a desired temperature trajectory. The proposed controller is used during the heating phase of the SMA actuator. The controller proves to be effective in tracking step-wise and continuous trajectories.

  2. Power shifts track serial position and modulate encoding in human episodic memory.

    Serruya, Mijail D; Sederberg, Per B; Kahana, Michael J

    2014-02-01

    The first events in a series exert a powerful influence on cognition and behavior in both humans and animals. This is known as the law of primacy. Here, we analyze the neural correlates of primacy in humans by analyzing electrocorticographic recordings in 84 neurosurgical patients as they studied and subsequently recalled lists of common words. We found that spectral power in the gamma frequency band (28-100 Hz) was elevated at the start of the list and gradually subsided, whereas lower frequency (2-8 Hz) delta and theta band power exhibited the opposite trend. This gradual shift in the power spectrum was found across a widespread network of brain regions. The degree to which the subsequent memory effect was modulated by list (serial) position was most pronounced in medial temporal lobe structures. These results suggest that globally increased gamma and decreased delta-theta spectral powers reflect a brain state that predisposes medial temporal lobe structures to enhance the encoding and maintenance of early list items.

  3. Externally induced frontoparietal synchronization modulates network dynamics and enhances working memory performance.

    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.

  4. Effect of two yoga-based relaxation techniques on memory scores and state anxiety

    Telles Shirley

    2009-08-01

    Full Text Available Abstract Background A yoga practice involving cycles of yoga postures and supine rest (called cyclic meditation was previously shown to improve performance in attention tasks more than relaxation in the corpse posture (shavasana. This was ascribed to reduced anxiety, though this was not assessed. Methods In fifty-seven male volunteers (group average age ± S.D., 26.6 ± 4.5 years the immediate effect of two yoga relaxation techniques was studied on memory and state anxiety. All participants were assessed before and after (i Cyclic meditation (CM practiced for 22:30 minutes on one day and (ii an equal duration of Supine rest (SR or the corpse posture (shavasana, on another day. Sections of the Wechsler memory scale (WMS were used to assess; (i attention and concentration (digit span forward and backward, and (ii associate learning. State anxiety was assessed using Spielberger's State-Trait Anxiety Inventory (STAI. Results There was a significant improvement in the scores of all sections of the WMS studied after both CM and SR, but, the magnitude of change was more after CM compared to after SR. The state anxiety scores decreased after both CM and SR, with a greater magnitude of decrease after CM. There was no correlation between percentage change in memory scores and state anxiety for either session. Conclusion A cyclical combination of yoga postures and supine rest in CM improved memory scores immediately after the practice and decreased state anxiety more than rest in a classical yoga relaxation posture (shavasana.

  5. A dynamic plasmonic manipulation technique assisted by phase modulation of an incident optical vortex beam

    Yuan, G H; Wang, Q; Tan, P S; Lin, J; Yuan, X-C

    2012-01-01

    A novel phase modulation method for dynamic manipulation of surface plasmon polaritons (SPPs) with a phase engineered optical vortex (OV) beam illuminating on nanoslits is experimentally demonstrated. Because of the unique helical phase carried by an OV beam, dynamic control of SPP multiple focusing and standing wave generation is realized by changing the OV beam’s topological charge constituent with the help of a liquid-crystal spatial light modulator. Measurement of SPP distributions with near-field scanning optical microscopy showed an excellent agreement with numerical predictions. The proposed phase modulation technique for manipulating SPPs features has seemingly dynamic and reconfigurable advantages, with profound potential for development of SPP coupling, routing, multiplexing and high-resolution imaging devices on plasmonic chips. (paper)

  6. New Technique for Luminosity Measurement Using 3D Pixel Modules in the ATLAS IBL Detector

    Liu, Peilian; The ATLAS collaboration

    2017-01-01

    The Insertable b-Layer ( IBL ) is the innermost layer of the ATLAS tracking system. It consists of planar pixel modules in the central region and 3D modules at two extremities. We use the cluster length distributions in 3D sensor modules of the IBL to determine the number of primary charged particles per event and suppress backgrounds. This Pixel Cluster Counting ( PCC ) algorithm provides a bunch-by-bunch luminosity measurement. An accurate luminosity measurement is a key component for precision measurements at the Large Hadron Collider and one of the largest uncertainties on the luminosity determination in ATLAS arises from the long-term stability of the measurement technique. The comparison of the PCC algorithm with other existing algorithms provides key insights in assessing and reducing such uncertainty.

  7. Dopamine Modulation of Hippocampal — Prefrontal Cortical Interaction Drives Memory-Guided Behavior

    Goto, Yukiori; Grace, Anthony A.

    2007-01-01

    Information gleaned from learning and memory processes is essential in guiding behavior towards a specific goal. However, the neural mechanisms that determine how these processes are effectively utilized to guide goal-directed behavior are unknown. Here, we show that rats utilize retrospective and prospective memory and flexible switching between these two memory processes to guide behaviors to obtain rewards. We found that retrospective memory is mainly processed in the hippocampus (HPC), bu...

  8. Interactions Between Epinephrine, Ascending Vagal Fibers and Central Noradrenergic Systems in Modulating Memory for Emotionally Arousing Events.

    Cedric L. Williams

    2012-06-01

    Full Text Available It is well established that exposure to emotionally laden events initiates secretion of the arousal related hormone epinephrine in the periphery. These neuroendocrine changes and the subsequent increase in peripheral physiological output play an integral role in modulating brain systems involved in memory formation. The impermeability of the blood brain barrier to epinephrine represents an important obstacle in understanding how peripheral hormones initiate neurochemical changes in the brain that lead to effective memory formation. This obstacle necessitated the identity of a putative pathway capable of conveying physiological changes produced by epinephrine to limbic structures that incorporate arousal and affect related information into memory. A major theme of the proposed studies is that ascending fibers of the vagus nerve may represent such a mechanism. This hypothesis was tested by evaluating the contribution of ascending vagal fibers in modulating memory for responses learned under behavioral conditions that produce emotional arousal by manipulating appetitive stimuli. A combination of electrophysiological recording of vagal afferent fibers and in vivo microdialysis was employed in a second study to simultaneously assess how elevations in peripheral levels of epinephrine affect vagal nerve discharge and the subsequent potentiation of norepinephrine release in the basolateral amygdala. The final study used double immunohistochemistry labeling of c-fos and dopamine beta hydroxylase, the enzyme for norepinephrine synthesis to determine if epinephrine administration alone or stimulation of the vagus nerve at an intensity identical to that which improved memory in Experiment 1 produces similar patterns of neuronal activity in brain areas involved in processing memory for emotional events. Findings emerging from this collection of studies establish the importance of ascending fibers of the vagus nerve as an essential pathway for conveying the

  9. Radiation doses during chest examinations using dose modulation techniques in multislice CT scanner

    Livingstone, Roshan S.; Pradip, Joe; Dinakran, Paul M.; Srikanth, B.

    2010-01-01

    Objectives: To evaluate the radiation dose and image quality using a manual protocol and dose modulation techniques in a 6-slice CT scanner. Materials and Methods: Two hundred and twenty-one patients who underwent contrast-enhanced CT of the chest were included in the study. For the manual protocol settings, constant tube potential (kV) and tube current-time product (mAs) of 140 kV and 120 mAs, respectively, were used. The angular and z-axis dose modulation techniques utilized a constant tube potential of 140 kV; mAs values were automatically selected by the machine. Effective doses were calculated using dose-length product (DLP) values and the image quality was assessed using the signal-to-noise (SNR) ratio values. Mean effective doses using manual protocol for patients of weights 40-60 kg, 61-80 kg, and 81 kg and above were 8.58 mSv, 8.54 mSv, and 9.07 mSv, respectively. Mean effective doses using z-axis dose modulation for patients of weights 40-60 kg, 61-80 kg, and 81 kg and above were 4.95 mSv, 6.87 mSv, and 10.24 mSv, respectively. The SNR at the region of the liver for patients of body weight of 40-60 kg was 5.1 H, 6.2 H, and 8.8 H for manual, angular, and z-axis dose modulation, respectively. Conclusion: Dose reduction of up to 15% was achieved using angular dose modulation and of up to 42% using z-axis dose modulation, with acceptable diagnostic image quality compared to the manual protocol. (author)

  10. Level of Processing Modulates the Neural Correlates of Emotional Memory Formation

    Ritchey, Maureen; LaBar, Kevin S.; Cabeza, Roberto

    2011-01-01

    Emotion is known to influence multiple aspects of memory formation, including the initial encoding of the memory trace and its consolidation over time. However, the neural mechanisms whereby emotion impacts memory encoding remain largely unexplored. The present study used a levels-of-processing manipulation to characterize the impact of emotion on…

  11. Design of the 12-bit Delta-Sigma Modulator using SC Technique for Vibration Sensor Output Processing

    M. Pavlik

    2012-04-01

    Full Text Available The work deals with the design of the 12-bit Delta-Sigma modulator using switched capacitors (SC technique. The modulator serves to vibration sensor output processing. The first part describes the Delta-Sigma modulator parameters definition. Results of the proposed topology ideal model were presented as well. Next, the Delta-Sigma modulator circuitry on the transistor level was done. The ONSemiconductor I2T100 0.7 um CMOS technology was used for design. Then, the Delta-Sigma modulator nonidealities were simulated and implemented into the MATLAB ideal model of the modulator. The model of real Delta-Sigma modulator was derived. Consequently, modulator coefficients were optimized. Finally, the corner analysis of the Delta-Sigma modulator with the optimized coefficients was simulated. The value of SNDR = 82.2 dB (ENOB = 13.4 bits was achieved.

  12. Scaling Techniques for Massive Scale-Free Graphs in Distributed (External) Memory

    Pearce, Roger

    2013-05-01

    We present techniques to process large scale-free graphs in distributed memory. Our aim is to scale to trillions of edges, and our research is targeted at leadership class supercomputers and clusters with local non-volatile memory, e.g., NAND Flash. We apply an edge list partitioning technique, designed to accommodate high-degree vertices (hubs) that create scaling challenges when processing scale-free graphs. In addition to partitioning hubs, we use ghost vertices to represent the hubs to reduce communication hotspots. We present a scaling study with three important graph algorithms: Breadth-First Search (BFS), K-Core decomposition, and Triangle Counting. We also demonstrate scalability on BG/P Intrepid by comparing to best known Graph500 results. We show results on two clusters with local NVRAM storage that are capable of traversing trillion-edge scale-free graphs. By leveraging node-local NAND Flash, our approach can process thirty-two times larger datasets with only a 39% performance degradation in Traversed Edges Per Second (TEPS). © 2013 IEEE.

  13. Advanced Packaging Materials and Techniques for High Power TR Module: Standard Flight vs. Advanced Packaging

    Hoffman, James Patrick; Del Castillo, Linda; Miller, Jennifer; Jenabi, Masud; Hunter, Donald; Birur, Gajanana

    2011-01-01

    The higher output power densities required of modern radar architectures, such as the proposed DESDynI [Deformation, Ecosystem Structure, and Dynamics of Ice] SAR [Synthetic Aperture Radar] Instrument (or DSI) require increasingly dense high power electronics. To enable these higher power densities, while maintaining or even improving hardware reliability, requires advances in integrating advanced thermal packaging technologies into radar transmit/receive (TR) modules. New materials and techniques have been studied and compared to standard technologies.

  14. Density-controllable nonvolatile memory devices having metal nanocrystals through chemical synthesis and assembled by spin-coating technique

    Wang Guangli; Chen Yubin; Shi Yi; Pu Lin; Pan Lijia; Zhang Rong; Zheng Youdou

    2010-01-01

    A novel two-step method is employed, for the first time, to fabricate nonvolatile memory devices that have metal nanocrystals. First, size-averaged Au nanocrystals are synthesized chemically; second, they are assembled into memory devices by a spin-coating technique at room temperature. This attractive approach makes it possible to tailor the diameter and control the density of nanocrystals individually. In addition, processes at room temperature prevent Au diffusion, which is a main concern for the application of metal nanocrystal-based memory. The experimental results, both the morphology characterization and the electrical measurements, reveal that there is an optimum density of nanocrystal monolayer to balance between long data retention and a large hysteresis memory window. At the same time, density-controllable devices could also feed the preferential emphasis on either memory window or retention time. All these facts confirm the advantages and novelty of our two-step method. (semiconductor devices)

  15. Advanced digital modulation: Communication techniques and monolithic GaAs technology

    Wilson, S. G.; Oliver, J. D., Jr.; Kot, R. C.; Richards, C. R.

    1983-01-01

    Communications theory and practice are merged with state-of-the-art technology in IC fabrication, especially monolithic GaAs technology, to examine the general feasibility of a number of advanced technology digital transmission systems. Satellite-channel models with (1) superior throughput, perhaps 2 Gbps; (2) attractive weight and cost; and (3) high RF power and spectrum efficiency are discussed. Transmission techniques possessing reasonably simple architectures capable of monolithic fabrication at high speeds were surveyed. This included a review of amplitude/phase shift keying (APSK) techniques and the continuous-phase-modulation (CPM) methods, of which MSK represents the simplest case.

  16. Effect of positive emotion on consolidation of memory for faces: the modulation of facial valence and facial gender.

    Wang, Bo

    2013-01-01

    Studies have shown that emotion elicited after learning enhances memory consolidation. However, no prior studies have used facial photos as stimuli. This study examined the effect of post-learning positive emotion on consolidation of memory for faces. During the learning participants viewed neutral, positive, or negative faces. Then they were assigned to a condition in which they either watched a 9-minute positive video clip, or a 9-minute neutral video. Then 30 minutes after the learning participants took a surprise memory test, in which they made "remember", "know", and "new" judgements. The findings are: (1) Positive emotion enhanced consolidation of recognition for negative male faces, but impaired consolidation of recognition for negative female faces; (2) For males, recognition for negative faces was equivalent to that for positive faces; for females, recognition for negative faces was better than that for positive faces. Our study provides the important evidence that effect of post-learning emotion on memory consolidation can extend to facial stimuli and such an effect can be modulated by facial valence and facial gender. The findings may shed light on establishing models concerning the influence of emotion on memory consolidation.

  17. Dopamine D1 receptor stimulation modulates the formation and retrieval of novel object recognition memory: Role of the prelimbic cortex.

    Pezze, Marie A; Marshall, Hayley J; Fone, Kevin C F; Cassaday, Helen J

    2015-11-01

    Previous studies have shown that dopamine D1 receptor antagonists impair novel object recognition memory but the effects of dopamine D1 receptor stimulation remain to be determined. This study investigated the effects of the selective dopamine D1 receptor agonist SKF81297 on acquisition and retrieval in the novel object recognition task in male Wistar rats. SKF81297 (0.4 and 0.8 mg/kg s.c.) given 15 min before the sampling phase impaired novel object recognition evaluated 10 min or 24 h later. The same treatments also reduced novel object recognition memory tested 24 h after the sampling phase and when given 15 min before the choice session. These data indicate that D1 receptor stimulation modulates both the encoding and retrieval of object recognition memory. Microinfusion of SKF81297 (0.025 or 0.05 μg/side) into the prelimbic sub-region of the medial prefrontal cortex (mPFC) in this case 10 min before the sampling phase also impaired novel object recognition memory, suggesting that the mPFC is one important site mediating the effects of D1 receptor stimulation on visual recognition memory. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

  18. DAT genotype modulates striatal processing and long-term memory for items associated with reward and punishment.

    Wittmann, Bianca C; Tan, Geoffrey C; Lisman, John E; Dolan, Raymond J; Düzel, Emrah

    2013-09-01

    Previous studies have shown that appetitive motivation enhances episodic memory formation via a network including the substantia nigra/ventral tegmental area (SN/VTA), striatum and hippocampus. This functional magnetic resonance imaging (fMRI) study now contrasted the impact of aversive and appetitive motivation on episodic long-term memory. Cue pictures predicted monetary reward or punishment in alternating experimental blocks. One day later, episodic memory for the cue pictures was tested. We also investigated how the neural processing of appetitive and aversive motivation and episodic memory were modulated by dopaminergic mechanisms. To that end, participants were selected on the basis of their genotype for a variable number of tandem repeat polymorphism of the dopamine transporter (DAT) gene. The resulting groups were carefully matched for the 5-HTTLPR polymorphism of the serotonin transporter gene. Recognition memory for cues from both motivational categories was enhanced in participants homozygous for the 10-repeat allele of the DAT, the functional effects of which are not known yet, but not in heterozygous subjects. In comparison with heterozygous participants, 10-repeat homozygous participants also showed increased striatal activity for anticipation of motivational outcomes compared to neutral outcomes. In a subsequent memory analysis, encoding activity in striatum and hippocampus was found to be higher for later recognized items in 10-repeat homozygotes compared to 9/10-repeat heterozygotes. These findings suggest that processing of appetitive and aversive motivation in the human striatum involve the dopaminergic system and that dopamine plays a role in memory for both types of motivational information. In accordance with animal studies, these data support the idea that encoding of motivational events depends on dopaminergic processes in the hippocampus. © 2013 The Authors. Published by Elsevier Ltd. All rights reserved.

  19. Patients with chronic insomnia have selective impairments in memory that are modulated by cortisol.

    Chen, Gui-Hai; Xia, Lan; Wang, Fang; Li, Xue-Wei; Jiao, Chuan-An

    2016-10-01

    Memory impairment is a frequent complaint in insomniacs; however, it is not consistently demonstrated. It is unknown whether memory impairment in insomniacs involves neuroendocrine dysfunction. The participants in this study were selected from the clinical setting and included 21 patients with chronic insomnia disorder (CID), 25 patients with insomnia and comorbid depressive disorder (CDD), and 20 control participants without insomnia. We evaluated spatial working and reference memory, object working and reference memory, and object recognition memory using the Nine Box Maze Test. We also evaluated serum neuroendocrine hormone levels. Compared to the controls, the CID patients made significantly more errors in spatial working and object recognition memory (p memory types (p memory (r = .534, p = .033) and negatively correlated with the errors in object recognition memory (r = -.659, p = .006) in the CID patients. The results suggest that the CID patients had selective memory impairment, which may be mediated by increased cortisol levels. © 2016 Society for Psychophysiological Research.

  20. Context-dependent modulation of hippocampal and cortical recruitment during remote spatial memory retrieval.

    Lopez, Joëlle; Herbeaux, Karin; Cosquer, Brigitte; Engeln, Michel; Muller, Christophe; Lazarus, Christine; Kelche, Christian; Bontempi, Bruno; Cassel, Jean-Christophe; de Vasconcelos, Anne Pereira

    2012-04-01

    According to systems consolidation, as hippocampal-dependent memories mature over time, they become additionally (or exclusively) dependent on extra-hippocampal structures. We assessed the recruitment of hippocampal and cortical structures on remote memory retrieval in a performance-degradation resistant (PDR; no performance degradation with time) versus performance-degradation prone (PDP; performance degraded with time) context. Using a water-maze task in two contexts with a hidden platform and three control conditions (home cage, visible platform with or without access to distal cues), we compared neuronal activation (c-Fos imaging) patterns in the dorsal hippocampus and the medial prefrontal cortex (mPFC) after the retrieval of recent (5 days) versus remote (25 days) spatial memory. In the PDR context, the hippocampus exhibited greater c-Fos protein expression on remote than recent memory retrieval, be it in the visible or hidden platform group. In the PDP context, hippocampal activation increased at the remote time point and only in the hidden platform group. In the anterior cingulate cortex, c-Fos expression was greater for remote than for recent memory retrieval and only in the PDR context. The necessity of the mPFC for remote memory retrieval in the PDR context was confirmed using region-specific lidocaine inactivation, which had no impact on recent memory. Conversely, inactivation of the dorsal hippocampus impaired both recent and remote memory in the PDR context, and only recent memory in the PDP context, in which remote memory performance was degraded. While confirming that neuronal circuits supporting spatial memory consolidation are reorganized in a time-dependent manner, our findings further indicate that mPFC and hippocampus recruitment (i) depends on the content and perhaps the strength of the memory and (ii) may be influenced by the environmental conditions (e.g., cue saliency, complexity) in which memories are initially formed and subsequently

  1. Pre-stimulus BOLD-network activation modulates EEG spectral activity during working memory retention

    Mara eKottlow

    2015-05-01

    Full Text Available Working memory (WM processes depend on our momentary mental state and therefore exhibit considerable fluctuations. Here, we investigate the interplay of task-preparatory and task-related brain activity as represented by pre-stimulus BOLD-fluctuations and spectral EEG from the retention periods of a visual WM task. Visual WM is used to maintain sensory information in the brain enabling the performance of cognitive operations and is associated with mental health.We tested 22 subjects simultaneously with EEG and fMRI while performing a visuo-verbal Sternberg task with two different loads, allowing for the temporal separation of preparation, encoding, retention and retrieval periods.Four temporally coherent networks - the default mode network (DMN, the dorsal attention, the right and the left WM network - were extracted from the continuous BOLD data by means of a group ICA. Subsequently, the modulatory effect of these networks’ pre-stimulus activation upon retention-related EEG activity in the theta, alpha and beta frequencies was analyzed. The obtained results are informative in the context of state-dependent information processing.We were able to replicate two well-known load-dependent effects: the frontal-midline theta increase during the task and the decrease of pre-stimulus DMN activity. As our main finding, these two measures seem to depend on each other as the significant negative correlations at frontal-midline channels suggested. Thus, suppressed pre-stimulus DMN levels facilitated later task related frontal midline theta increases. In general, based on previous findings that neuronal coupling in different frequency bands may underlie distinct functions in WM retention, our results suggest that processes reflected by spectral oscillations during retention seem not only to be online synchronized with activity in different attention-related networks but are also modulated by activity in these networks during preparation intervals.

  2. Do serotonin(1-7) receptors modulate short and long-term memory?

    Meneses, A

    2007-05-01

    Evidence from invertebrates to human studies indicates that serotonin (5-hydroxytryptamine; 5-HT) system modulates short- (STM) and long-term memory (LTM). This work is primarily focused on analyzing the contribution of 5-HT, cholinergic and glutamatergic receptors as well as protein synthesis to STM and LTM of an autoshaping learning task. It was observed that the inhibition of hippocampal protein synthesis or new mRNA did not produce a significant effect on autoshaping STM performance but it did impair LTM. Both non-contingent protein inhibition and 5-HT depletion showed no effects. It was basically the non-selective 5-HT receptor antagonist cyproheptadine, which facilitated STM. However, the blockade of glutamatergic and cholinergic transmission impaired STM. In contrast, the selective 5-HT(1B) receptor antagonist SB-224289 facilitated both STM and LTM. Selective receptor antagonists for the 5-HT(1A) (WAY100635), 5-HT(1D) (GR127935), 5-HT(2A) (MDL100907), 5-HT(2C/2B) (SB-200646), 5-HT(3) (ondansetron) or 5-HT(4) (GR125487), 5-HT(6) (Ro 04-6790, SB-399885 and SB-35713) or 5-HT(7) (SB-269970) did not impact STM. Nevertheless, WAY100635, MDL100907, SB-200646, GR125487, Ro 04-6790, SB-399885 or SB-357134 facilitated LTM. Notably, some of these changes shown to be independent of food-intake. Concomitantly, these data indicate that '5-HT tone via 5-HT(1B) receptors' might function in a serial manner from STM to LTM, whereas working in parallel using 5-HT(1A), 5-HT(2A), 5-HT(2B/2C), 5-HT(4), or 5-HT(6) receptors.

  3. Characterization of ultrashort laser pulses employing self-phase modulation dispersion-scan technique

    Sharba, A. B.; Chekhlov, O.; Wyatt, A. S.; Pattathil, R.; Borghesi, M.; Sarri, G.

    2018-03-01

    We present a new phase characterization technique for ultrashort laser pulses that employs self-phase modulation (SPM) in the dispersion scan approach. The method can be implemented by recording a set of nonlinearly modulated spectra generated with a set of known chirp values. The unknown phase of the pulse is retrieved by linking the recorded spectra to the initial spectrum of the pulse via a phase function guessed by a function minimization iterative algorithm. This technique has many advantages over the dispersion scan techniques that use frequency conversion processes. Mainly, the use of SPM cancels out the phase and group velocity mismatch errors and dramatically widens the spectral acceptance of the nonlinear medium and the range of working wavelength. The robustness of the technique is demonstrated with smooth and complex phase retrievals using numerical examples. The method is shown to be not affected by the spatial distribution of the beam or the presence of nonlinear absorption process. In addition, we present an efficient method for phase representation based on a summation of a set of Gaussian functions. The independence of the functions from each other prevents phase coupling of any kind and facilitates a flexible phase representation.

  4. Advanced Intensity-Modulation Continuous-Wave Lidar Techniques for Column CO2 Measurements

    Campbell, J. F.; Lin, B.; Obland, M. D.; Liu, Z.; Kooi, S. A.; Fan, T. F.; Nehrir, A. R.; Meadows, B.; Browell, E. V.

    2016-12-01

    Advanced Intensity-Modulation Continuous-Wave Lidar Techniques for Column CO2 MeasurementsJoel F. Campbell1, Bing Lin1, Michael D. Obland1, Zhaoyan Liu1, Susan Kooi2, Tai-Fang Fan2, Amin R. Nehrir1, Byron Meadows1, Edward V. Browell31NASA Langley Research Center, Hampton, VA 23681 2SSAI, NASA Langley Research Center, Hampton, VA 23681 3STARSS-II Affiliate, NASA Langley Research Center, Hampton, VA 23681 AbstractGlobal and regional atmospheric carbon dioxide (CO2) measurements for the NASA Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) space mission and the Atmospheric Carbon and Transport (ACT) - America project are critical for improving our understanding of global CO2 sources and sinks. Advanced Intensity-Modulated Continuous-Wave (IM-CW) lidar techniques are investigated as a means of facilitating CO2 measurements from space and airborne platforms to meet the ASCENDS and ACT-America science measurement requirements. In recent numerical, laboratory and flight experiments we have successfully used the Binary Phase Shift Keying (BPSK) modulation technique to uniquely discriminate surface lidar returns from intermediate aerosol and cloud returns. We demonstrate the utility of BPSK to eliminate sidelobes in the range profile as a means of making Integrated Path Differential Absorption (IPDA) column CO2 measurements in the presence of optically thin clouds, thereby minimizing bias errors caused by the clouds. Furthermore, high accuracy and precision ranging to the surface as well as to the top of intermediate cloud layers, which is a requirement for the inversion of column CO2 number density measurements to column CO2 mixing ratios, has been demonstrated using new sub-meter hyperfine interpolation techniques that takes advantage of the periodicity of the modulation waveforms. The BPSK technique under investigation has excellent auto-correlation properties while possessing a finite bandwidth. These techniques are used in a new data processing

  5. Glucose enhancement of memory is modulated by trait anxiety in healthy adolescent males

    Smith, Michael; Hii, Hilary; Foster, Jonathan; van Eekelen, Anke

    2011-01-01

    Glucose administration is associated with memory enhancement in healthy young individuals under conditions of divided attention at encoding. While the specific neurocognitive mechanisms underlying this ‘glucose memory facilitation effect’ are currently uncertain, it is thought that individual differences in glucoregulatory efficiency may alter an individual’s sensitivity to the glucose memory facilitation effect. In the present study, we sought to investigate whether basal hypothalamic–pituit...

  6. Level of processing modulates the neural correlates of emotional memory formation

    Ritchey, Maureen; LaBar, Kevin S.; Cabeza, Roberto

    2010-01-01

    Emotion is known to influence multiple aspects of memory formation, including the initial encoding of the memory trace and its consolidation over time. However, the neural mechanisms whereby emotion impacts memory encoding remain largely unexplored. The present study employed a levels-of-processing manipulation to characterize the impact of emotion on encoding with and without the influence of elaborative processes. Participants viewed emotionally negative, neutral, and positive scenes under ...

  7. BDNF Variants May Modulate Long-Term Visual Memory Performance in a Healthy Cohort

    Nesli Avgan

    2017-03-01

    Full Text Available Brain-derived neurotrophic factor (BDNF is involved in numerous cognitive functions including learning and memory. BDNF plays an important role in synaptic plasticity in humans and rats with BDNF shown to be essential for the formation of long-term memories. We previously identified a significant association between the BDNF Val66Met polymorphism (rs6265 and long-term visual memory (p-value = 0.003 in a small cohort (n = 181 comprised of healthy individuals who had been phenotyped for various aspects of memory function. In this study, we have extended the cohort to 597 individuals and examined multiple genetic variants across both the BDNF and BDNF-AS genes for association with visual memory performance as assessed by the Wechsler Memory Scale—Fourth Edition subtests Visual Reproduction I and II (VR I and II. VR I assesses immediate visual memory, whereas VR II assesses long-term visual memory. Genetic association analyses were performed for 34 single nucleotide polymorphisms genotyped on Illumina OmniExpress BeadChip arrays with the immediate and long-term visual memory phenotypes. While none of the BDNF and BDNF-AS variants were shown to be significant for immediate visual memory, we found 10 variants (including the Val66Met polymorphism (p-value = 0.006 that were nominally associated, and three variants (two variants in BDNF and one variant in the BDNF-AS locus that were significantly associated with long-term visual memory. Our data therefore suggests a potential role for BDNF, and its anti-sense transcript BDNF-AS, in long-term visual memory performance.

  8. BDNF Variants May Modulate Long-Term Visual Memory Performance in a Healthy Cohort.

    Avgan, Nesli; Sutherland, Heidi G; Spriggens, Lauren K; Yu, Chieh; Ibrahim, Omar; Bellis, Claire; Haupt, Larisa M; Shum, David H K; Griffiths, Lyn R

    2017-03-17

    Brain-derived neurotrophic factor (BDNF) is involved in numerous cognitive functions including learning and memory. BDNF plays an important role in synaptic plasticity in humans and rats with BDNF shown to be essential for the formation of long-term memories. We previously identified a significant association between the BDNF Val66Met polymorphism (rs6265) and long-term visual memory ( p -value = 0.003) in a small cohort ( n = 181) comprised of healthy individuals who had been phenotyped for various aspects of memory function. In this study, we have extended the cohort to 597 individuals and examined multiple genetic variants across both the BDNF and BDNF-AS genes for association with visual memory performance as assessed by the Wechsler Memory Scale-Fourth Edition subtests Visual Reproduction I and II (VR I and II). VR I assesses immediate visual memory, whereas VR II assesses long-term visual memory. Genetic association analyses were performed for 34 single nucleotide polymorphisms genotyped on Illumina OmniExpress BeadChip arrays with the immediate and long-term visual memory phenotypes. While none of the BDNF and BDNF-AS variants were shown to be significant for immediate visual memory, we found 10 variants (including the Val66Met polymorphism ( p -value = 0.006)) that were nominally associated, and three variants (two variants in BDNF and one variant in the BDNF-AS locus) that were significantly associated with long-term visual memory. Our data therefore suggests a potential role for BDNF , and its anti-sense transcript BDNF-AS , in long-term visual memory performance.

  9. Noradrenergic activation of the basolateral amygdala modulates the consolidation of object-in-context recognition memory

    Barsegyan, Areg; McGaugh, James L.; Roozendaal, Benno

    2014-01-01

    Noradrenergic activation of the basolateral complex of the amygdala (BLA) is well known to enhance the consolidation of long-term memory of highly emotionally arousing training experiences. The present study investigated whether such noradrenergic activation of the BLA also influences the consolidation of object-in-context recognition memory, a low-arousing training task assessing episodic-like memory. Male Sprague-Dawley rats were exposed to two identical objects in one context for either 3 ...

  10. Defining quality criteria for online continuing medical education modules using modified nominal group technique.

    Shortt, S E D; Guillemette, Jean-Marc; Duncan, Anne Marie; Kirby, Frances

    2010-01-01

    The rapid increase in the use of the Internet for continuing education by physicians suggests the need to define quality criteria for accredited online modules. Continuing medical education (CME) directors from Canadian medical schools and academic researchers participated in a consensus process, Modified Nominal Group Technique, to develop agreement on the most important quality criteria to guide module development. Rankings were compared to responses to a survey of a subset of Canadian Medical Association (CMA) members. A list of 17 items was developed, of which 10 were deemed by experts to be important and 7 were considered secondary. A quality module would: be needs-based; presented in a clinical format; utilize evidence-based information; permit interaction with content and experts; facilitate and attempt to document practice change; be accessible for later review; and include a robust course evaluation. There was less agreement among CMA members on criteria ranking, with consensus on ranking reached on only 12 of 17 items. In contrast to experts, members agreed that the need to assess performance change as a result of an educational experience was not important. This project identified 10 quality criteria for accredited online CME modules that representatives of Canadian organizations involved in continuing education believe should be taken into account when developing learning products. The lack of practitioner support for documentation of change in clinical behavior may suggest that they favor traditional attendance- or completion-based CME; this finding requires further research.

  11. Plastic modulation of episodic memory networks in the aging brain with cognitive decline.

    Bai, Feng; Yuan, Yonggui; Yu, Hui; Zhang, Zhijun

    2016-07-15

    Social-cognitive processing has been posited to underlie general functions such as episodic memory. Episodic memory impairment is a recognized hallmark of amnestic mild cognitive impairment (aMCI) who is at a high risk for dementia. Three canonical networks, self-referential processing, executive control processing and salience processing, have distinct roles in episodic memory retrieval processing. It remains unclear whether and how these sub-networks of the episodic memory retrieval system would be affected in aMCI. This task-state fMRI study constructed systems-level episodic memory retrieval sub-networks in 28 aMCI and 23 controls using two computational approaches: a multiple region-of-interest based approach and a voxel-level functional connectivity-based approach, respectively. These approaches produced the remarkably similar findings that the self-referential processing network made critical contributions to episodic memory retrieval in aMCI. More conspicuous alterations in self-referential processing of the episodic memory retrieval network were identified in aMCI. In order to complete a given episodic memory retrieval task, increases in cooperation between the self-referential processing network and other sub-networks were mobilized in aMCI. Self-referential processing mediate the cooperation of the episodic memory retrieval sub-networks as it may help to achieve neural plasticity and may contribute to the prevention and treatment of dementia. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. From Specificity to Sensitivity: Affective states modulate visual working memory for emotional expressive faces

    Thomas eMaran

    2015-08-01

    Full Text Available Previous findings suggest that visual working memory preferentially remembers angry looking faces. However, the meaning of facial actions is construed in relation to context. To date, there are no studies investigating the role of perceiver-based context when processing emotional cues in visual working memory. To explore the influence of affective context on visual working memory for faces, we conducted two experiments using both a visual working memory task for emotionally expressive faces and a mood induction procedure. Affective context was manipulated by unpleasant (Experiment 1 and pleasant (Experiment 2 IAPS pictures in order to induce an affect high in motivational intensity (defensive or appetitive, respectively compared to a low arousal control condition. Results indicated specifically increased sensitivity of visual working memory for angry looking faces in the neutral condition. Enhanced visual working memory for angry faces was prevented by inducing affects of high motivational intensity. In both experiments, affective states led to a switch from specific enhancement of angry expressions in visual working memory to an equally sensitive representation of all emotional expressions. Our findings demonstrate that emotional expressions are of different behavioral relevance for the receiver depending on the affective context, supporting a functional organization of visual working memory along with flexible resource allocation. In visual working memory, stimulus processing adjusts to situational requirements and transitions from a specifically prioritizing default mode in predictable environments to a sensitive, hypervigilant mode in exposure to emotional events.

  13. Development of the MCM-D technique for pixel detector modules

    Grah, Christian

    2005-01-01

    This thesis treats a copper--polymer based thin film technology, the MCM-D technique and its application when building hybrid pixel detector modules. The ATLAS experiment at the LHC will be equipped with a pixel detector system. The basic mechanical units of the pixel detector are multi chip modules. The main components of these modules are: 16 electronic chips, a controller chip and a large sensor tile, featuring more than 46000 sensor cells. MCM-D is a superior technique to build the necessary signal bus system and the power distribution system directly on the active sensor tile. In collaboration with the Fraunhofer Institute for Reliability and Microintegration, IZM, the thin film process is reviewed and enhanced. The multi layer system was designed and optimized for the interconnection system as well as for the 46000 pixel contacts. Laboratory measurements on prototypes prove that complex routing schemes for geometrically optimized single chips are suitable and have negligible influence on the front--end ...

  14. High Performance ZVT with Bus Clamping Modulation Technique for Single Phase Full Bridge Inverters

    Xia, Yinglai; Ayyanar, Raja

    2016-03-20

    This paper proposes a topology based on bus clamping modulation and zero-voltage-transition (ZVT) technique to realize zero-voltage-switching (ZVS) for all the main switches of the full bridge inverters, and inherent ZVS and/or ZCS for the auxiliary switches. The advantages of the strategy include significant reduction in the turn-on loss of the ZVT auxiliary switches which typically account for a major part of the total loss in other ZVT circuits, and reduction in the voltage ratings of auxiliary switches. The modulation scheme and the commutation stages are analyzed in detail. Finally, a 1kW, 500 kHz switching frequency inverter of the proposed topology using SiC MOSFETs has been built to validate the theoretical analysis. The ZVT with bus clamping modulation technique of fixed timing and adaptive timing schemes are implemented in DSP TMS320F28335 resulting in full ZVS for the main switches in the full bridge inverter. The proposed scheme can save up to 33 % of the switching loss compared with no ZVT case.

  15. Breast-conserving radiation therapy using combined electron and intensity-modulated radiotherapy technique

    Li, J.G.; Williams, S.S.; Goffinet, D.R.; Boer, A.L.; Xing, L.

    2000-01-01

    An electron beam with appropriate energy was combined with four intensity modulated photon beams. The direction of the electron beam was chosen to be tilted 10-20 laterally from the anteroposterior direction. Two of the intensity-modulated photon beams had the same gantry angles as the conventional tangential fields, whereas the other two beams were rotated 15-25' toward the anteroposterior directions from the first two photon beams. An iterative algorithm was developed which optimizes the weight of the electron beam as well as the fluence profiles of the photon beams for a given patient. Two breast cancer patients with early-stage breast tumors were planned with the new technique and the results were compared with those from 3D planning using tangential fields as well as 9-field intensity-modulated radiotherapy (IMRT) techniques. The combined electron and IMRT plans showed better dose conformity to the target with significantly reduced dose to the ipsilateral lung and, in the case of the left-breast patient, reduced dose to the heart, than the tangential field plans. In both the right-sided and left-sided breast plans, the dose to other normal structures was similar to that from conventional plans and was much smaller than that from the 9-field IMRT plans. The optimized electron beam provided between 70 to 80% of the prescribed dose at the depth of maximum dose of the electron beam. The combined electron and IMRT technique showed improvement over the conventional treatment technique using tangential fields with reduced dose to the ipsilateral lung and the heart. The customized beam directions of the four IMRT fields also kept the dose to other critical structures to a minimum. (author)

  16. Working memory load related modulations of the oscillatory brain activity. N-back ERD/ERS study

    Nakao, Yoshiaki; Tamura, Toshiyo; Kodabashi, Atsushi; Fujimoto, Toshiro; Yarita, Masaru

    2011-01-01

    In recent cognitive neuroscience, a lot of studies of the human working memory were examined, and electroencephalography (EEG) measurements during n-back task were often used. However, they were almost studied by event related potentials (ERP) analysis. In the ERP study, time-locked components can be elicited, but non time-locked components such as the modulated brain oscillatory activity might be lost by an averaging procedure. To elucidate the contribution of the modulations of the brain oscillatory activity to the human working memory, we examined event related desynchronization (ERD)/event related synchronization (ERS) analysis on the source waveforms during n-back task. Source waveforms were calculated from a source model which was constructed with the sources seeded from fMRI meta-analysis of n-back task and additional sources in the orbitofrontal cortex and the visual cortex estimated with P100 and P360 components in the n-back ERP. Our results suggested the network which included the prefrontal cortex and the parietal lobe had a contribution to human working memory process, and it was mediated by theta oscillatory activity. (author)

  17. Selective attention supports working memory maintenance by modulating perceptual processing of distractors.

    Sreenivasan, Kartik K; Jha, Amishi P

    2007-01-01

    Selective attention has been shown to bias sensory processing in favor of relevant stimuli and against irrelevant or distracting stimuli in perceptual tasks. Increasing evidence suggests that selective attention plays an important role during working memory maintenance, possibly by biasing sensory processing in favor of to-be-remembered items. In the current study, we investigated whether selective attention may also support working memory by biasing processing against irrelevant and potentially distracting information. Event-related potentials (ERPs) were recorded while subjects (n = 22) performed a delayed-recognition task for faces and shoes. The delay period was filled with face or shoe distractors. Behavioral performance was impaired when distractors were congruent with the working memory domain (e.g., face distractor during working memory for faces) relative to when distractors were incongruent with the working memory domain (e.g., face distractor during shoe working memory). If attentional biasing against distractor processing is indeed functionally relevant in supporting working memory maintenance, perceptual processing of distractors is predicted to be attenuated when distractors are more behaviorally intrusive relative to when they are nonintrusive. As such, we predicted that perceptual processing of distracting faces, as measured by the face-sensitive N170 ERP component, would be reduced in the context of congruent (face) working memory relative to incongruent (shoe) working memory. The N170 elicited by distracting faces demonstrated reduced amplitude during congruent versus incongruent working memory. These results suggest that perceptual processing of distracting faces may be attenuated due to attentional biasing against sensory processing of distractors that are most behaviorally intrusive during working memory maintenance.

  18. Levels of Interference in Long and Short-Term Memory Differentially Modulate Non-REM and REM Sleep.

    Fraize, Nicolas; Carponcy, Julien; Joseph, Mickaël Antoine; Comte, Jean-Christophe; Luppi, Pierre-Hervé; Libourel, Paul-Antoine; Salin, Paul-Antoine; Malleret, Gaël; Parmentier, Régis

    2016-12-01

    It is commonly accepted that sleep is beneficial to memory processes, but it is still unclear if this benefit originates from improved memory consolidation or enhanced information processing. It has thus been proposed that sleep may also promote forgetting of undesirable and non-essential memories, a process required for optimization of cognitive resources. We tested the hypothesis that non-rapid eye movement sleep (NREMS) promotes forgetting of irrelevant information, more specifically when processing information in working memory (WM), while REM sleep (REMS) facilitates the consolidation of important information. We recorded sleep patterns of rats trained in a radial maze in three different tasks engaging either the long-term or short-term storage of information, as well as a gradual level of interference. We observed a transient increase in REMS amount on the day the animal learned the rule of a long-term/reference memory task (RM), and, in contrast, a positive correlation between the performance of rats trained in a WM task involving an important processing of interference and the amount of NREMS or slow wave activity. Various oscillatory events were also differentially modulated by the type of training involved. Notably, NREMS spindles and REMS rapid theta increase with RM training, while sharp-wave ripples increase with all types of training. These results suggest that REMS, but also rapid oscillations occurring during NREMS would be specifically implicated in the long-term memory in RM, whereas NREMS and slow oscillations could be involved in the forgetting of irrelevant information required for WM. © 2016 Associated Professional Sleep Societies, LLC.

  19. Modulation of short-term social memory in rats by adenosine A1 and A(2A) receptors.

    Prediger, Rui D S; Takahashi, Reinaldo N

    2005-03-16

    The recognition of an unfamiliar juvenile rat by an adult rat has been shown to imply short-term memory processes. The present study was designed to examine the role of adenosine receptors in the short-term social memory of rats using the social recognition paradigm. Adenosine (5.0-10.0 mg/kg), the selective adenosine A1 receptor agonist 2-chloro-N6-cyclopentyladenosine (CCPA, 0.025-0.05 mg/kg) and the selective adenosine A(2A) receptor agonist N6-[2-(3,5-dimethoxyphenyl)-2-(2-methylphenyl)ethyl]adenosine (DPMA, 1.0-5.0 mg/kg), given by i.p. route 30 min before the test, disrupted the juvenile recognition ability of adult rats. This negative effect of adenosine (5.0 mg/kg, i.p.) on social memory was prevented by pretreatment with the non-selective adenosine receptor antagonist caffeine (10.0 mg/kg, i.p.), the adenosine A1 antagonist 8-cyclopentyl-1,3-dipropylxanthine (DPCPX, 1.0 mg/kg, i.p.) and the adenosine A(2A) antagonist 4-(2-[7-amino-2-{2-furyl}{1,2,4}triazolo-{2,3-a}{1,3,5}triazin-5-yl-amino]ethyl)phenol (ZM241385, 1.0 mg/kg, i.p.). Furthermore, acute administration of caffeine (10.0-30.0 mg/kg, i.p.), DPCPX (1.0-3.0 mg/kg, i.p.) or ZM241385 (0.5-1.0 mg/kg, i.p.) improved the short-term social memory in a specific manner. These results indicate that adenosine modulates the short-term social memory in rats by acting on both A1 and A(2A) receptors, with adenosine receptor agonists and antagonists, respectively, disrupting and enhancing the social memory.

  20. Failure modes induced by natural radiation environments on DRAM memories: study, test methodology and mitigation technique

    Bougerol, A.

    2011-05-01

    DRAMs are frequently used in space and aeronautic systems. Their sensitivity to cosmic radiations have to be known in order to satisfy reliability requirements for critical applications. These evaluations are traditionally done with particle accelerators. However, devices become more complex with technology integration. Therefore new effects appear, inducing longer and more expensive tests. There is a complementary solution: the pulsed laser, which triggers similar effects as particles. Thanks to these two test tools, main DRAM radiation failure modes were studied: SEUs (Single Event Upset) in memory blocks, and SEFIs (Single Event Functional Interrupt) in peripheral circuits. This work demonstrates the influence of test patterns on SEU and SEFI sensitivities depending on technology used. In addition, this study identifies the origin of the most frequent type of SEFIs. Moreover, laser techniques were developed to quantify sensitive surfaces of the different effects. This work led to a new test methodology for industry, in order to optimize test cost and efficiency using both pulsed laser beams and particle accelerators. Finally, a new fault tolerant technique is proposed: based on DRAM cell radiation immunity when discharged, this technique allows to correct all bits of a logic word. (author)

  1. Cognition-emotion interactions are modulated by working memory capacity in individuals with schizophrenia.

    Strauss, Gregory P; Lee, Bern G; Waltz, James A; Robinson, Benjamin M; Brown, Jaime K; Gold, James M

    2012-11-01

    Prior research provides evidence for aberrant cognition-emotion interactions in schizophrenia. In the current study, we aimed to extend these findings by administering the "distractor devaluation" task to 40 individuals with schizophrenia and 32 demographically matched healthy controls. The task consisted of a simple visual search task for neutral faces, followed by an evaluative response made for one of the search items (or a novel item) to determine whether prior attentional selection results in a devaluation of a previously unattended stimulus. We also manipulated working memory demands by preceding the search array with a memory array that required subjects to hold 0, 1, or 2 items in working memory while performing the search array and devaluation task, to determine whether the normative process by which attentional states influence evaluative response is limited by working memory capacity. Results indicated that individuals with schizophrenia demonstrated the typical distractor devaluation effect at working memory load 0, suggesting intact evaluative response. However, the devaluation effect was absent at working memory loads of 1 and 2, suggesting that normal evaluative responses can be abolished in people with schizophrenia when working memory capacity is exceeded. Thus, findings provide further evidence for normal evaluative response in schizophrenia, but clarify that these normal experiences may not hold when working memory demands are too high. Copyright © 2012 Elsevier B.V. All rights reserved.

  2. Environmental context effects on episodic memory are dependent on retrieval mode and modulated by neuropsychological status.

    Barak, Ohr; Vakil, Eli; Levy, Daniel A

    2013-01-01

    Contextual change or constancy between occasions of memory formation and retrieval are commonly assumed to affect retrieval success, yet such effects may be inconsistent, and the processes leading to the pattern of effects are still not well understood. We conducted a systematic investigation of environmental context effects on memory, using a range of materials (common objects, pictures of familiar and unfamiliar faces, words, and sentences), and four types of retrieval (free recall, cued recall, recognition, and order memory), all assessed within participants. Additionally, we examined the influence of mnemonic challenge on context effects by examining both healthy participants and a group of patients in rehabilitation following traumatic brain injury (TBI). We found no effects of contextual factors on tests of recognition for either group of participants, but effects did emerge for cued and free recall, with the most prominent effects being on memory for objects. Furthermore, while patients' memory abilities in general were impaired relative to the comparison group, they exhibited greater influences of contextual reinstatement on several recall tasks. These results support suggestions that environmental context effects on memory are dependent on retrieval mode and on the extent to which retrieval is challenging because of neurocognitive status. Additionally, findings of environmental context effects in memory-impaired TBI patients suggest that by harnessing such preserved indirect memory (e.g., using reminder technologies), it may be possible to ameliorate TBI patients' difficulties in explicit remembering.

  3. Pulse-modulated multilevel data storage in an organic ferroelectric resistive memory diode

    Lee, J.; Breemen, A.J.J.M. van; Khikhlovskyi, V.; Kemerink, M.; Janssen, R.A.J.; Gelinck, G.H.

    2016-01-01

    We demonstrate multilevel data storage in organic ferroelectric resistive memory diodes consisting of a phase-separated blend of P(VDF-TrFE) and a semiconducting polymer. The dynamic behaviour of the organic ferroelectric memory diode can be described in terms of the inhomogeneous field mechanism

  4. Staying cool when things get hot: Emotion regulation modulates neural mechanisms of memory encoding

    Jasmeet P Hayes

    2010-12-01

    Full Text Available During times of emotional stress, individuals often engage in emotion regulation to reduce the experiential and physiological impact of negative emotions. Interestingly, emotion regulation strategies also influence memory encoding of the event. Cognitive reappraisal is associated with enhanced memory while expressive suppression is associated with impaired explicit memory of the emotional event. However, the mechanism by which these emotion regulation strategies affect memory is unclear. We used event-related fMRI to investigate the neural mechanisms that give rise to memory formation during emotion regulation. Twenty-five participants viewed negative pictures while alternately engaging in cognitive reappraisal, expressive suppression, or passive viewing. As part of the subsequent memory design, participants returned to the laboratory two weeks later for a surprise memory test. Behavioral results showed a reduction in negative affect and a retention advantage for reappraised stimuli relative to the other conditions. Imaging results showed that successful encoding during reappraisal was uniquely associated with greater co-activation of the left inferior frontal gyrus, amygdala and hippocampus, suggesting a possible role for elaborative encoding of negative memories. This study provides neurobehavioral evidence that engaging in cognitive reappraisal is advantageous to both affective and mnemonic processes.

  5. Fatty-acid binding proteins modulate sleep and enhance long-term memory consolidation in Drosophila.

    Jason R Gerstner

    2011-01-01

    Full Text Available Sleep is thought to be important for memory consolidation, since sleep deprivation has been shown to interfere with memory processing. However, the effects of augmenting sleep on memory formation are not well known, and testing the role of sleep in memory enhancement has been limited to pharmacological and behavioral approaches. Here we test the effect of overexpressing the brain-type fatty acid binding protein (Fabp7 on sleep and long-term memory (LTM formation in Drosophila melanogaster. Transgenic flies carrying the murine Fabp7 or the Drosophila homologue dFabp had reduced baseline sleep but normal LTM, while Fabp induction produced increases in both net sleep and LTM. We also define a post-training consolidation "window" that is sufficient for the observed Fabp-mediated memory enhancement. Since Fabp overexpression increases consolidated daytime sleep bouts, these data support a role for longer naps in improving memory and provide a novel role for lipid-binding proteins in regulating memory consolidation concurrently with changes in behavioral state.

  6. Memory

    Wager, Nadia

    2017-01-01

    This chapter will explore a response to traumatic victimisation which has divided the opinions of psychologists at an exponential rate. We will be examining amnesia for memories of childhood sexual abuse and the potential to recover these memories in adulthood. Whilst this phenomenon is generally accepted in clinical circles, it is seen as highly contentious amongst research psychologists, particularly experimental cognitive psychologists. The chapter will begin with a real case study of a wo...

  7. Differential immediate and sustained memory enhancing effects of alpha7 nicotinic receptor agonists and allosteric modulators in rats

    Thomsen, Morten Skøtt; El-Sayed, Mona; Mikkelsen, Jens D

    2011-01-01

    of repeated administration of α7 nAChR agonists. We further compare the effect of agonists to that of α7 nAChR positive allosteric modulators (PAMs), which do not induce upregulation of the α7 nAChR. Using the social discrimination test as a measure of short-term memory, we show that the α7 nAChR agonist A......-582941 improves short-term memory immediately after repeated (7× daily), but not a single administration. The α7 nAChR PAMs PNU-120596 and AVL-3288 do not affect short-term memory immediately after a single or repeated administration. This demonstrates a fundamental difference in the behavioral effects...... of agonists and PAMs that may be relevant for clinical development. Importantly, A-582941 and AVL-3288 increase short-term memory 24 hrs after repeated, but not a single, administration, suggesting that repeated administration of both agonists and PAMs may produce sustained effects on cognitive performance...

  8. Modulation of steady state functional connectivity in the default mode and working memory networks by cognitive load.

    Newton, Allen T; Morgan, Victoria L; Rogers, Baxter P; Gore, John C

    2011-10-01

    Interregional correlations between blood oxygen level dependent (BOLD) magnetic resonance imaging (fMRI) signals in the resting state have been interpreted as measures of connectivity across the brain. Here we investigate whether such connectivity in the working memory and default mode networks is modulated by changes in cognitive load. Functional connectivity was measured in a steady-state verbal identity N-back task for three different conditions (N = 1, 2, and 3) as well as in the resting state. We found that as cognitive load increases, the functional connectivity within both the working memory the default mode network increases. To test whether functional connectivity between the working memory and the default mode networks changed, we constructed maps of functional connectivity to the working memory network as a whole and found that increasingly negative correlations emerged in a dorsal region of the posterior cingulate cortex. These results provide further evidence that low frequency fluctuations in BOLD signals reflect variations in neural activity and suggests interaction between the default mode network and other cognitive networks. Copyright © 2010 Wiley-Liss, Inc.

  9. Integrated cannabinoid CB1 receptor transmission within the amygdala-prefrontal cortical pathway modulates neuronal plasticity and emotional memory encoding.

    Tan, Huibing; Lauzon, Nicole M; Bishop, Stephanie F; Bechard, Melanie A; Laviolette, Steven R

    2010-06-01

    The cannabinoid CB1 receptor system is functionally involved in the processing and encoding of emotionally salient sensory information, learning and memory. The CB1 receptor is found in high concentrations in brain structures that are critical for emotional processing, including the basolateral amygdala (BLA) and the medial prefrontal cortex (mPFC). In addition, synaptic plasticity in the form of long-term potentiation (LTP) within the BLA > mPFC pathway is an established correlate of exposure to emotionally salient events. We performed a series of in vivo LTP studies by applying tetanic stimulation to the BLA combined with recordings of local field potentials within prelimbic cortical (PLC) region of the rat mPFC. Systemic pretreatment with AM-251 dose dependently blocked LTP along the BLA-PLC pathway and also the behavioral acquisition of conditioned fear memories. We next performed a series of microinfusion experiments wherein CB1 receptor transmission within the BLA > PLC circuit was pharmacologically blocked. Asymmetrical, interhemispheric blockade of CB1 receptor transmission along the BLA > PLC pathway prevented the acquisition of emotionally salient associative memory. Our results indicate that coordinated CB1 receptor transmission within the BLA > PLC pathway is critically involved in the encoding of emotional fear memories and modulates neural plasticity related to the encoding of emotionally salient associative learning.

  10. Robust Automatic Modulation Classification Technique for Fading Channels via Deep Neural Network

    Jung Hwan Lee

    2017-08-01

    Full Text Available In this paper, we propose a deep neural network (DNN-based automatic modulation classification (AMC for digital communications. While conventional AMC techniques perform well for additive white Gaussian noise (AWGN channels, classification accuracy degrades for fading channels where the amplitude and phase of channel gain change in time. The key contributions of this paper are in two phases. First, we analyze the effectiveness of a variety of statistical features for AMC task in fading channels. We reveal that the features that are shown to be effective for fading channels are different from those known to be good for AWGN channels. Second, we introduce a new enhanced AMC technique based on DNN method. We use the extensive and diverse set of statistical features found in our study for the DNN-based classifier. The fully connected feedforward network with four hidden layers are trained to classify the modulation class for several fading scenarios. Numerical evaluation shows that the proposed technique offers significant performance gain over the existing AMC methods in fading channels.

  11. Modulation of the consolidation and reconsolidation of fear memory by three different serotonin receptors in hippocampus.

    Schmidt, S D; Furini, C R G; Zinn, C G; Cavalcante, L E; Ferreira, F F; Behling, J A K; Myskiw, J C; Izquierdo, I

    2017-07-01

    The process of memory formation is complex and highly dynamic. During learning, the newly acquired information is found in a fragile and labile state. Through a process known as consolidation, which requires specific mechanisms such as protein synthesis, the memory trace is stored and stabilized. It is known that when a consolidated memory is recalled, it again becomes labile and sensitive to disruption. To be maintained, this memory must undergo an additional process of restabilization called reconsolidation, which requires another phase of protein synthesis. Memory consolidation has been studied for more than a century, while the molecular mechanisms underlying the memory reconsolidation are starting to be elucidated. For this, is essential compare the participation of important neurotransmitters and its receptors in both processes in brain regions that play a central role in the fear response learning. With focus on serotonin (5-HT), a well characterized neurotransmitter that has been strongly implicated in learning and memory, we investigated, in the CA1 region of the dorsal hippocampus, whether the latest discovered serotonergic receptors, 5-HT 5A , 5-HT 6 and 5-HT 7 , are involved in the consolidation and reconsolidation of contextual fear conditioning (CFC) memory. For this, male rats with cannulae implanted in the CA1 region received immediately after the training or reactivation session, or 3h post-reactivation of the CFC, infusions of agonists or antagonists of the 5-HT 5A , 5-HT 6 and 5-HT 7 receptors. After 24h, animals were subjected to a 3-min retention test. The results indicated that in the CA1 region of the hippocampus the 5-HT 5A , 5-HT 6 and 5-HT 7 serotonin receptors participate in the reconsolidation of the CFC memory 3h post-reactivation. Additionally, the results suggest that the 5-HT 6 and 5-HT 7 receptors also participate in the consolidation of the CFC memory. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. ADRA2B genotype differentially modulates stress-induced neural activity in the amygdala and hippocampus during emotional memory retrieval.

    Li, Shijia; Weerda, Riklef; Milde, Christopher; Wolf, Oliver T; Thiel, Christiane M

    2015-02-01

    Noradrenaline interacts with stress hormones in the amygdala and hippocampus to enhance emotional memory consolidation, but the noradrenergic-glucocorticoid interaction at retrieval, where stress impairs memory, is less understood. We used a genetic neuroimaging approach to investigate whether a genetic variation of the noradrenergic system impacts stress-induced neural activity in amygdala and hippocampus during recognition of emotional memory. This study is based on genotype-dependent reanalysis of data from our previous publication (Li et al. Brain Imaging Behav 2014). Twenty-two healthy male volunteers were genotyped for the ADRA2B gene encoding the α2B-adrenergic receptor. Ten deletion carriers and 12 noncarriers performed an emotional face recognition task, while their brain activity was measured with fMRI. During encoding, 50 fearful and 50 neutral faces were presented. One hour later, they underwent either an acute stress (Trier Social Stress Test) or a control procedure which was followed immediately by the retrieval session, where participants had to discriminate between 100 old and 50 new faces. A genotype-dependent modulation of neural activity at retrieval was found in the bilateral amygdala and right hippocampus. Deletion carriers showed decreased neural activity in the amygdala when recognizing emotional faces in control condition and increased amygdala activity under stress. Noncarriers showed no differences in emotional modulated amygdala activation under stress or control. Instead, stress-induced increases during recognition of emotional faces were present in the right hippocampus. The genotype-dependent effects of acute stress on neural activity in amygdala and hippocampus provide evidence for noradrenergic-glucocorticoid interaction in emotional memory retrieval.

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

    Anne-Lise eSaive

    2014-06-01

    Full Text Available 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 to 72 hours 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.

  14. Selective updating of working memory content modulates meso-cortico-striatal activity.

    Murty, Vishnu P; Sambataro, Fabio; Radulescu, Eugenia; Altamura, Mario; Iudicello, Jennifer; Zoltick, Bradley; Weinberger, Daniel R; Goldberg, Terry E; Mattay, Venkata S

    2011-08-01

    Accumulating evidence from non-human primates and computational modeling suggests that dopaminergic signals arising from the midbrain (substantia nigra/ventral tegmental area) mediate striatal gating of the prefrontal cortex during the selective updating of working memory. Using event-related functional magnetic resonance imaging, we explored the neural mechanisms underlying the selective updating of information stored in working memory. Participants were scanned during a novel working memory task that parses the neurophysiology underlying working memory maintenance, overwriting, and selective updating. Analyses revealed a functionally coupled network consisting of a midbrain region encompassing the substantia nigra/ventral tegmental area, caudate, and dorsolateral prefrontal cortex that was selectively engaged during working memory updating compared to the overwriting and maintenance of working memory content. Further analysis revealed differential midbrain-dorsolateral prefrontal interactions during selective updating between low-performing and high-performing individuals. These findings highlight the role of this meso-cortico-striatal circuitry during the selective updating of working memory in humans, which complements previous research in behavioral neuroscience and computational modeling. Published by Elsevier Inc.

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

    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

  16. Top-Down Modulation of Auditory-Motor Integration during Speech Production: The Role of Working Memory.

    Guo, Zhiqiang; Wu, Xiuqin; Li, Weifeng; Jones, Jeffery A; Yan, Nan; Sheft, Stanley; Liu, Peng; Liu, Hanjun

    2017-10-25

    Although working memory (WM) is considered as an emergent property of the speech perception and production systems, the role of WM in sensorimotor integration during speech processing is largely unknown. We conducted two event-related potential experiments with female and male young adults to investigate the contribution of WM to the neurobehavioural processing of altered auditory feedback during vocal production. A delayed match-to-sample task that required participants to indicate whether the pitch feedback perturbations they heard during vocalizations in test and sample sequences matched, elicited significantly larger vocal compensations, larger N1 responses in the left middle and superior temporal gyrus, and smaller P2 responses in the left middle and superior temporal gyrus, inferior parietal lobule, somatosensory cortex, right inferior frontal gyrus, and insula compared with a control task that did not require memory retention of the sequence of pitch perturbations. On the other hand, participants who underwent extensive auditory WM training produced suppressed vocal compensations that were correlated with improved auditory WM capacity, and enhanced P2 responses in the left middle frontal gyrus, inferior parietal lobule, right inferior frontal gyrus, and insula that were predicted by pretraining auditory WM capacity. These findings indicate that WM can enhance the perception of voice auditory feedback errors while inhibiting compensatory vocal behavior to prevent voice control from being excessively influenced by auditory feedback. This study provides the first evidence that auditory-motor integration for voice control can be modulated by top-down influences arising from WM, rather than modulated exclusively by bottom-up and automatic processes. SIGNIFICANCE STATEMENT One outstanding question that remains unsolved in speech motor control is how the mismatch between predicted and actual voice auditory feedback is detected and corrected. The present study

  17. Intensity-modulated radiotherapy with simultaneous modulated accelerated boost technique and chemotherapy in patients with nasopharyngeal carcinoma

    Fareed, Muhammad M; AlAmro, Abdullah S; Bayoumi, Yasser; Tunio, Mutahir A; Ismail, Abdul S; Akasha, Rashad; Mubasher, Mohamed; Al Asiri, Mushabbab

    2013-01-01

    To present our experience of intensity-modulated radiotherapy (IMRT) with simultaneous modulated accelerated radiotherapy (SMART) boost technique in patients with nasopharyngeal carcinoma (NPC). Sixty eight patients of NPC were treated between April 2006 and December 2011 including 45 males and 23 females with mean age of 46 (range 15–78). Stage distribution was; stage I 3, stage II 7, stage III 26 and stage IV 32. Among 45 (66.2%) evaluated patients for presence of Epstein-Barr virus (EBV), 40 (88.8%) were positive for EBV. Median radiation doses delivered to gross tumor volume (GTV) and positive neck nodes were 66–70 Gy, 63 Gy to clinical target volume (CTV) and 50.4 Gy to clinically negative neck. In addition 56 (82.4%) patients with bulky tumors (T4/N2+) received neoadjuvant chemotherapy 2–3 cycles (Cisplatin/Docetaxel or Cisplatin/Epirubicin or Cisplatin/5 Flourouracil). Concurrent chemotherapy with radiation was weekly Cisplatin 40 mg/m 2 (40 patients) or Cisplatin 100 mg/m 2 (28 patients). With a median follow up of 20 months (range 3–43), one patient developed local recurrence, two experienced regional recurrences and distant failure was seen in 3 patients. Estimated 3 year disease free survival (DFS) was 94%. Three year DFS for patients with EBV was 100% as compared to 60% without EBV (p = 0.0009). Three year DFS for patients with undifferentiated histology was 98% as compared to 82% with other histologies (p = 0.02). Acute grade 3 toxicity was seen as 21 (30.9%) having G-III mucositis and 6 (8.8%) with G-III skin reactions. Late toxicity was minimal and loss of taste was seen in 3 patients (7.5%) at time of analysis. IMRT with SMART in combination with chemotherapy is feasible and effective in terms of both the clinical response and safety profile. EBV, histopathology and nodal involvement were found important prognostic factors for locoregional recurrence

  18. HDAC3 Inhibitor RGFP966 Modulates Neuronal Memory for Vocal Communication Signals in a Songbird Model

    Mimi L. Phan

    2017-09-01

    Full Text Available Epigenetic mechanisms that modify chromatin conformation have recently been under investigation for their contributions to learning and the formation of memory. For example, the role of enzymes involved in histone acetylation are studied in the formation of long-lasting memories because memory consolidation requires gene expression events that are facilitated by an open state of chromatin. We recently proposed that epigenetic events may control the entry of specific sensory features into long-term memory by enabling transcription-mediated neuronal plasticity in sensory brain areas. Histone deacetylases, like HDAC3, may thereby regulate the specific sensory information that is captured for entry into long-term memory stores (Phan and Bieszczad, 2016. To test this hypothesis, we used an HDAC3-selective inhibitor (RGFP966 to determine whether its application after an experience with a sound stimulus with unique acoustic features could contribute to the formation of a memory that would assist in mediating its later recognition. We gave adult male zebra finches limited exposure to unique conspecific songs (20 repetitions each, well below the normal threshold to form long-term memory, followed by treatment with RGFP966 or vehicle. In different groups, we either made multi-electrode recordings in the higher auditory area NCM (caudal medial nidopallidum, or determined expression of an immediate early gene, zenk (also identified as zif268, egr-1, ngfi-a and krox24, known to participate in neuronal memory in this system. We found that birds treated with RGFP966 showed neuronal memory after only limited exposure, while birds treated with vehicle did not. Strikingly, evidence of neuronal memory in NCM induced by HDAC3-inhibition was lateralized to the left-hemisphere, consistent with our finding that RGFP966-treatment also elevated zenk expression only in the left hemisphere. The present findings show feasibility for epigenetic mechanisms to control neural

  19. HDAC3 Inhibitor RGFP966 Modulates Neuronal Memory for Vocal Communication Signals in a Songbird Model.

    Phan, Mimi L; Gergues, Mark M; Mahidadia, Shafali; Jimenez-Castillo, Jorge; Vicario, David S; Bieszczad, Kasia M

    2017-01-01

    Epigenetic mechanisms that modify chromatin conformation have recently been under investigation for their contributions to learning and the formation of memory. For example, the role of enzymes involved in histone acetylation are studied in the formation of long-lasting memories because memory consolidation requires gene expression events that are facilitated by an open state of chromatin. We recently proposed that epigenetic events may control the entry of specific sensory features into long-term memory by enabling transcription-mediated neuronal plasticity in sensory brain areas. Histone deacetylases, like HDAC3, may thereby regulate the specific sensory information that is captured for entry into long-term memory stores (Phan and Bieszczad, 2016). To test this hypothesis, we used an HDAC3-selective inhibitor (RGFP966) to determine whether its application after an experience with a sound stimulus with unique acoustic features could contribute to the formation of a memory that would assist in mediating its later recognition. We gave adult male zebra finches limited exposure to unique conspecific songs (20 repetitions each, well below the normal threshold to form long-term memory), followed by treatment with RGFP966 or vehicle. In different groups, we either made multi-electrode recordings in the higher auditory area NCM (caudal medial nidopallidum), or determined expression of an immediate early gene, zenk (also identified as zif268 , egr-1 , ngfi-a and krox24 ), known to participate in neuronal memory in this system. We found that birds treated with RGFP966 showed neuronal memory after only limited exposure, while birds treated with vehicle did not. Strikingly, evidence of neuronal memory in NCM induced by HDAC3-inhibition was lateralized to the left-hemisphere, consistent with our finding that RGFP966-treatment also elevated zenk expression only in the left hemisphere. The present findings show feasibility for epigenetic mechanisms to control neural plasticity

  20. Direct visualization of polarization reversal of organic ferroelectric memory transistor by using charge modulated reflectance imaging

    Otsuka, Takako; Taguchi, Dai; Manaka, Takaaki; Iwamoto, Mitsumasa

    2017-11-01

    By using the charge modulated reflectance (CMR) imaging technique, charge distribution in the pentacene organic field-effect transistor (OFET) with a ferroelectric gate insulator [P(VDF-TrFE)] was investigated in terms of polarization reversal of the P(VDF-TrFE) layer. We studied the polarization reversal process and the carrier spreading process in the OFET channel. The I-V measurement showed a hysteresis behavior caused by the spontaneous polarization of P(VDF-TrFE), but the hysteresis I-V curve changes depending on the applied drain bias, possibly due to the gradual shift of the polarization reversal position in the OFET channel. CMR imaging visualized the gradual shift of the polarization reversal position and showed that the electrostatic field formed by the polarization of P(VDF-TrFE) contributes to hole and electron injection into the pentacene layer and the carrier distribution is significantly dependent on the direction of the polarization. The polarization reversal position in the channel region is governed by the electrostatic potential, and it happens where the potential reaches the coercive voltage of P(VDF-TrFE). The transmission line model developed on the basis of the Maxwell-Wagner effect element analysis well accounts for this polarization reversal process in the OFET channel.

  1. Studies on laws of stress-magnetization based on magnetic memory testing technique

    Ren, Shangkun; Ren, Xianzhi

    2018-03-01

    Metal magnetic memory (MMM) testing technique is a novel testing method which can early test stress concentration status of ferromagnetic components. Under the different maximum tensile stress, the relationship between the leakage magnetic field of at certain point of cold rolled steel specimen and the tensile stress was measured during the process of loading and unloading by repeated. It shows that when the maximum tensile stress is less than 610 MPa, the relationship between the magnetic induction intensity and the stress is linear; When the maximum tensile stress increase from 610 MPa to 653 MPa of yield point, the relationship between the magnetic induction intensity and the tensile becomes bending line. The location of the extreme point of the bending line will move rapidly from the position of smaller stress to the larger stress position, and the variation of magnetic induction intensity increases rapidly. When the maximum tensile stress is greater than the 653 MPa of yield point, the variation of the magnetic induction intensity remains large, and the position of the extreme point moves very little. In theoretical aspects, tensile stress is to be divided into ordered stress and disordered stress. In the stage of elastic stress, a microscopic model of the order stress magnetization is established, and the conclusions are in good agreement with the experimental data. In the plastic deformation stage, a microscopic model of disordered stress magnetization is established, and the conclusions are in good agreement with the experimental data, too. The research results can provide reference for the accurate quantitative detection and evaluation of metal magnetic memory testing technology.

  2. [Positioning errors of CT common rail technique in intensity-modulated radiotherapy for nasopharyngeal carcinoma].

    Tian, Fei; Xu, Zihai; Mo, Li; Zhu, Chaohua; Chen, Chaomin

    2012-11-01

    To evaluate the value of CT common rail technique for application in intensity-modulated radiotherapy for nasopharyngeal carcinoma (NPC). Twenty-seven NPC patients underwent Somatom CT scans using the Siemens CTVision system prior to the commencement of the radiotherapy sessions. The acquired CT images were registered with the planning CT images using the matching function of the system to obtain the linear set-up errors of 3 directions, namely X (left to right), Y (superior to inferior), and Z (anterior to posterior). The errors were then corrected online on the moving couch. The 27 NPC patients underwent a total of 110 CT scans and the displacement deviations of the X, Y and Z directions were -0.16∓1.68 mm, 0.25∓1.66 mm, and 0.33∓1.09 mm, respectively. CT common rail technique can accurately and rapidly measure the space error between the posture and the target area to improve the set-up precision of intensity-modulated radiotherapy for NPC.

  3. Does emotion modulate the efficacy of spaced learning in recognition memory?

    Nicola Mammarella; Beth Fairfield; Alberto Di Domenico

    2014-01-01

    Memory for repeated items improves when presentations are spaced during study. Here, two experiments assessed the so-called spacing effect on a yes–no recognition memory task using affective and neutral words. In Experiment 1, a group of participants was asked to orient their attention to semantic features of target words (deep semantic analysis) that were consecutively repeated or spaced, while another group was engaged in a graphemic shallow analysis of words (Experiment 2). The depth of wo...

  4. Noradrenergic activation of the basolateral amygdala modulates the consolidation of object-in-context recognition memory

    Areg eBarsegyan

    2014-05-01

    Full Text Available Noradrenergic activation of the basolateral complex of the amygdala (BLA is well known to enhance the consolidation of long-term memory of highly emotionally arousing training experiences. The present study investigated whether such noradrenergic activation of the BLA also influences the consolidation of object-in-context recognition memory, a low-arousing training task assessing episodic-like memory. Male Sprague–Dawley rats were exposed to two identical objects in one context for either 3 or 10 min, immediately followed by exposure to two other identical objects in a distinctly different context. Immediately after the training they received bilateral intra-BLA infusions of norepinephrine (0.3, 1.0 or 3.0 μg or the β-adrenoceptor antagonist propranolol (0.1, 0.3 or 1.0 μg. On the 24-h retention test, rats were placed back into one of the training contexts with one copy of each of the two training objects. Thus, although both objects were familiar, one of the objects had not previously been encountered in this particular test context. Hence, if the animal generated a long-term memory for the association between an object and its context, it would spend significantly more time exploring the object that was not previously experienced in this context. Saline-infused control rats exhibited poor 24-h retention when given 3 min of training and good retention when given 10 min of training. Norepinephrine administered after 3 min of object-in-context training induced a dose-dependent memory enhancement, whereas propranolol administered after 10 min of training produced memory impairment. These findings provide evidence that posttraining noradrenergic activation of the BLA also enhances the consolidation of memory of object-in-context recognition training, enabling accuracy of episodic-like memories.

  5. Modality-specific alpha modulations facilitate long-term memory encoding in the presence of distracters.

    Jiang, Haiteng; van Gerven, Marcel A J; Jensen, Ole

    2015-03-01

    It has been proposed that long-term memory encoding is not only dependent on engaging task-relevant regions but also on disengaging task-irrelevant regions. In particular, oscillatory alpha activity has been shown to be involved in shaping the functional architecture of the working brain because it reflects the functional disengagement of specific regions in attention and memory tasks. We here ask if such allocation of resources by alpha oscillations generalizes to long-term memory encoding in a cross-modal setting in which we acquired the ongoing brain activity using magnetoencephalography. Participants were asked to encode pictures while ignoring simultaneously presented words and vice versa. We quantified the brain activity during rehearsal reflecting subsequent memory in the different attention conditions. The key finding was that successful long-term memory encoding is reflected by alpha power decreases in the sensory region of the to-be-attended modality and increases in the sensory region of the to-be-ignored modality to suppress distraction during rehearsal period. Our results corroborate related findings from attention studies by demonstrating that alpha activity is also important for the allocation of resources during long-term memory encoding in the presence of distracters.

  6. Evidence of estrogen modulation on memory processes for emotional content in healthy young women.

    Pompili, Assunta; Arnone, Benedetto; D'Amico, Mario; Federico, Paolo; Gasbarri, Antonella

    2016-03-01

    It is well accepted that emotional content can affect memory, interacting with the encoding and consolidation processes. The aim of the present study was to verify the effects of estrogens in the interplay of cognition and emotion. Images from the International Affective Pictures System, based on valence (pleasant, unpleasant and neutral), maintaining arousal constant, were viewed passively by two groups of young women in different cycle phases: a periovulatory group (PO), characterized by high level of estrogens and low level of progesterone, and an early follicular group (EF), characterized by low levels of both estrogens and progesterone. The electrophysiological responses to images were measured, and P300 peak was considered. One week later, long-term memory was tested by means of free recall. Intra-group analysis displayed that PO woman had significantly better memory for positive images, while EF women showed significantly better memory for negative images. The comparison between groups revealed that women in the PO phase had better memory performance for positive pictures than women in the EF phase, while no significant differences were found for negative and neutral pictures. According to the free recall results, the subjects in the PO group showed greater P300 amplitude, and shorter latency, for pleasant images compared with women in the EF group. Our results showed that the physiological hormonal fluctuation of estrogens during the menstrual cycle can influence memory, at the time of encoding, during the processing of emotional information. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Hippocampal leptin signaling reduces food intake and modulates food-related memory processing.

    Kanoski, Scott E; Hayes, Matthew R; Greenwald, Holly S; Fortin, Samantha M; Gianessi, Carol A; Gilbert, Jennifer R; Grill, Harvey J

    2011-08-01

    The increase in obesity prevalence highlights the need for a more comprehensive understanding of the neural systems controlling food intake; one that extends beyond food intake driven by metabolic need and considers that driven by higher-order cognitive factors. The hippocampus, a brain structure involved in learning and memory function, has recently been linked with food intake control. Here we examine whether administration of the adiposity hormone leptin to the dorsal and ventral sub-regions of the hippocampus influences food intake and memory for food. Leptin (0.1 μg) delivered bilaterally to the ventral hippocampus suppressed food intake and body weight measured 24 h after administration; a higher dose (0.4 μg) was needed to suppress intake following dorsal hippocampal delivery. Leptin administration to the ventral but not dorsal hippocampus blocked the expression of a conditioned place preference for food and increased the latency to run for food in an operant runway paradigm. Additionally, ventral but not dorsal hippocampal leptin delivery suppressed memory consolidation for the spatial location of food, whereas hippocampal leptin delivery had no effect on memory consolidation in a non-spatial appetitive response paradigm. Collectively these findings indicate that ventral hippocampal leptin signaling contributes to the inhibition of food-related memories elicited by contextual stimuli. To conclude, the results support a role for hippocampal leptin signaling in the control of food intake and food-related memory processing.

  8. A face to remember: emotional expression modulates prefrontal activity during memory formation.

    Sergerie, Karine; Lepage, Martin; Armony, Jorge L

    2005-01-15

    Emotion can exert a modulatory role on episodic memory. Several studies have shown that negative stimuli (e.g., words, pictures) are better remembered than neutral ones. Although facial expressions are powerful emotional stimuli and have been shown to influence perception and attention processes, little is known about their effect on memory. We used functional magnetic resonance imaging (fMRI) in humans to investigate the effects of expression (happy, neutral, and fearful) on prefrontal cortex (PFC) activity during the encoding of faces, using a subsequent memory effect paradigm. Our results show that activity in right PFC predicted memory for faces, regardless of expression, while a homotopic region in the left hemisphere was associated with successful encoding only for faces with an emotional expression. These findings are consistent with the proposed role of right dorsolateral PFC in successful encoding of nonverbal material, but also suggest that left DLPFC may be a site where integration of memory and emotional processes occurs. This study sheds new light on the current controversy regarding the hemispheric lateralization of PFC in memory encoding.

  9. Optical signal processing techniques and applications of optical phase modulation in high-speed communication systems

    Deng, Ning

    the speed limitation of electronics. Thus, all-optical signal processing techniques are highly desirable to support the necessary optical switching functionalities in future ultrahigh-speed optical packet-switching networks. To cope with the wide use of optical phase-modulated signals, in the thesis, an all-optical logic for DPSK or PSK input signals is developed, for the first time. Based on four-wave mixing in semiconductor optical amplifier, the structure of the logic gate is simple, compact, and capable of supporting ultrafast operation. In addition to the general logic processing, a simple label recognition scheme, as a specific signal processing function, is proposed for phase-modulated label signals. The proposed scheme can recognize any incoming label pattern according to the local pattern, and is potentially capable of handling variable-length label patterns. Optical access network with multicast overlay and centralized light sources. In the arena of optical access networks, wavelength division multiplexing passive optical network (WDM-PON) is a promising technology to deliver high-speed data traffic. However, most of proposed WDM-PONs only support conventional point-to-point service, and cannot meet the requirement of increasing demand on broadcast and multicast service. In this thesis, a simple network upgrade is proposed based on the traditional PON architecture to support both point-to-point and multicast service. In addition, the two service signals are modulated on the same lightwave carrier. The upstream signal is also remodulated on the same carrier at the optical network unit, which can significantly relax the requirement on wavelength management at the network unit.

  10. Dynamic range of frontoparietal functional modulation is associated with working memory capacity limitations in older adults.

    Hakun, Jonathan G; Johnson, Nathan F

    2017-11-01

    Older adults tend to over-activate regions throughout frontoparietal cortices and exhibit a reduced range of functional modulation during WM task performance compared to younger adults. While recent evidence suggests that reduced functional modulation is associated with poorer task performance, it remains unclear whether reduced range of modulation is indicative of general WM capacity-limitations. In the current study, we examined whether the range of functional modulation observed over multiple levels of WM task difficulty (N-Back) predicts in-scanner task performance and out-of-scanner psychometric estimates of WM capacity. Within our sample (60-77years of age), age was negatively associated with frontoparietal modulation range. Individuals with greater modulation range exhibited more accurate N-Back performance. In addition, despite a lack of significant relationships between N-Back and complex span task performance, range of frontoparietal modulation during the N-Back significantly predicted domain-general estimates of WM capacity. Consistent with previous cross-sectional findings, older individuals with less modulation range exhibited greater activation at the lowest level of task difficulty but less activation at the highest levels of task difficulty. Our results are largely consistent with existing theories of neurocognitive aging (e.g. CRUNCH) but focus attention on dynamic range of functional modulation asa novel marker of WM capacity-limitations in older adults. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. Memories.

    Brand, Judith, Ed.

    1998-01-01

    This theme issue of the journal "Exploring" covers the topic of "memories" and describes an exhibition at San Francisco's Exploratorium that ran from May 22, 1998 through January 1999 and that contained over 40 hands-on exhibits, demonstrations, artworks, images, sounds, smells, and tastes that demonstrated and depicted the biological,…

  12. Value-based modulation of memory encoding involves strategic engagement of fronto-temporal semantic processing regions.

    Cohen, Michael S; Rissman, Jesse; Suthana, Nanthia A; Castel, Alan D; Knowlton, Barbara J

    2014-06-01

    A number of prior fMRI studies have focused on the ways in which the midbrain dopaminergic reward system coactivates with hippocampus to potentiate memory for valuable items. However, another means by which people could selectively remember more valuable to-be-remembered items is to be selective in their use of effective but effortful encoding strategies. To broadly examine the neural mechanisms of value on subsequent memory, we used fMRI to assess how differences in brain activity at encoding as a function of value relate to subsequent free recall for words. Each word was preceded by an arbitrarily assigned point value, and participants went through multiple study-test cycles with feedback on their point total at the end of each list, allowing for sculpting of cognitive strategies. We examined the correlation between value-related modulation of brain activity and participants' selectivity index, which measures how close participants were to their optimal point total, given the number of items recalled. Greater selectivity scores were associated with greater differences in the activation of semantic processing regions, including left inferior frontal gyrus and left posterior lateral temporal cortex, during the encoding of high-value words relative to low-value words. Although we also observed value-related modulation within midbrain and ventral striatal reward regions, our fronto-temporal findings suggest that strategic engagement of deep semantic processing may be an important mechanism for selectively encoding valuable items.

  13. Value-based modulation of memory encoding involves strategic engagement of fronto-temporal semantic processing regions

    Cohen, Michael S.; Rissman, Jesse; Suthana, Nanthia A.; Castel, Alan D.; Knowlton, Barbara J.

    2014-01-01

    A number of prior fMRI studies have focused on the ways in which the midbrain dopaminergic reward system co-activates with hippocampus to potentiate memory for valuable items. However, another means by which people could selectively remember more valuable to-be-remembered items is to be selective in their use of effective but effortful encoding strategies. To broadly examine the neural mechanisms of value on subsequent memory, we used fMRI to examine how differences in brain activity at encoding as a function of value relate to subsequent free recall for words. Each word was preceded by an arbitrarily assigned point value, and participants went through multiple study-test cycles with feedback on their point total at the end of each list, allowing for sculpting of cognitive strategies. We examined the correlation between value-related modulation of brain activity and participants’ selectivity index, a measure of how close participants were to their optimal point total given the number of items recalled. Greater selectivity scores were associated with greater differences in activation of semantic processing regions, including left inferior frontal gyrus and left posterior lateral temporal cortex, during encoding of high-value words relative to low-value words. Although we also observed value-related modulation within midbrain and ventral striatal reward regions, our fronto-temporal findings suggest that strategic engagement of deep semantic processing may be an important mechanism for selectively encoding valuable items. PMID:24683066

  14. Chronic epigallocatechin-3-gallate ameliorates learning and memory deficits in diabetic rats via modulation of nitric oxide and oxidative stress.

    Baluchnejadmojarad, Tourandokht; Roghani, Mehrdad

    2011-10-31

    Due to anti-diabetic and antioxidant activity of green tea epigallocatechin gallate (EGCG) and the existence of evidence for its beneficial effect on cognition and memory, this research study was conducted to evaluate, for the first time, the efficacy of chronic EGCG on alleviation of learning and memory deficits in streptozotocin (STZ)-diabetic rats. Male Wistar rats were divided into control, diabetic, EGCG-treated-control and -diabetic groups. EGCG was administered at a dose of 20 and 40 mg/kg/day for 7 weeks. Learning and memory was evaluated using Y maze, passive avoidance, and radial 8-arm maze (RAM) tests. Oxidative stress markers and involvement of nitric oxide system were also evaluated. Alternation score of the diabetic rats in Y maze was lower than that of control and a significant impairment was observed in retention and recall in passive avoidance test (pRAM task and EGCG (40 mg/kg) significantly ameliorated these changes (pmemory respectively. Meanwhile, increased levels of malondialdehyde (MDA) and nitrite in diabetic rats significantly reduced due to EGCG treatment (pmemory deficits in STZ-diabetic rats through attenuation of oxidative stress and modulation of NO. Copyright © 2011 Elsevier B.V. All rights reserved.

  15. Interaction of multiple networks modulated by the working memory training based on real-time fMRI

    Shen, Jiahui; Zhang, Gaoyan; Zhu, Chaozhe; Yao, Li; Zhao, Xiaojie

    2015-03-01

    Neuroimaging studies of working memory training have identified the alteration of brain activity as well as the regional interactions within the functional networks such as central executive network (CEN) and default mode network (DMN). However, how the interaction within and between these multiple networks is modulated by the training remains unclear. In this paper, we examined the interaction of three training-induced brain networks during working memory training based on real-time functional magnetic resonance imaging (rtfMRI). Thirty subjects assigned to the experimental and control group respectively participated in two times training separated by seven days. Three networks including silence network (SN), CEN and DMN were identified by the training data with the calculated function connections within each network. Structural equation modeling (SEM) approach was used to construct the directional connectivity patterns. The results showed that the causal influences from the percent signal changes of target ROI to the SN were positively changed in both two groups, as well as the causal influence from the SN to CEN was positively changed in experimental group but negatively changed in control group from the SN to DMN. Further correlation analysis of the changes in each network with the behavioral improvements showed that the changes in SN were stronger positively correlated with the behavioral improvement of letter memory task. These findings indicated that the SN was not only a switch between the target ROI and the other networks in the feedback training but also an essential factor to the behavioral improvement.

  16. Larynx-sparing techniques using intensity-modulated radiation therapy for oropharyngeal cancer

    Bar Ad, Voichita, E-mail: voichita.bar-ad@jeffersonhospital.org [Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA (United States); Lin, Haibo [Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA (United States); Hwang, Wei-Ting [Department of Biostatistics and Epidemiology, University of Pennsylvania, Philadelphia, PA (United States); Deville, Curtiland [Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA (United States); Dutta, Pinaki R. [Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA (United States); Department of Biostatistics and Epidemiology, University of Pennsylvania, Philadelphia, PA (United States); Tochner, Zelig; Both, Stefan [Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA (United States)

    2012-01-01

    The purpose of the current study was to explore whether the laryngeal dose can be reduced by using 2 intensity-modulated radiation therapy (IMRT) techniques: whole-neck field IMRT technique (WF-IMRT) vs. junctioned IMRT (J-IMRT). The effect on planning target volumes (PTVs) coverage and laryngeal sparing was evaluated. WF-IMRT technique consisted of a single IMRT plan, including the primary tumor and the superior and inferior neck to the level of the clavicular heads. The larynx was defined as an organ at risk extending superiorly to cover the arytenoid cartilages and inferiorly to include the cricoid cartilage. The J-IMRT technique consisted of an IMRT plan for the primary tumor and the superior neck, matched to conventional antero-posterior opposing lower neck fields at the level of the thyroid notch. A central block was used for the anterior lower neck field at the level of the larynx to restrict the dose to the larynx. Ten oropharyngeal cancer cases were analyzed. Both the primary site and bilateral regional lymphatics were included in the radiotherapy targets. The averaged V95 for the PTV57.6 was 99.2% for the WF-IMRT technique compared with 97.4% (p = 0.02) for J-IMRT. The averaged V95 for the PTV64 was 99.9% for the WF-IMRT technique compared with 98.9% (p = 0.02) for J-IMRT and the averaged V95 for the PT70 was 100.0% for WF-IMRT technique compared with 99.5% (p = 0.04) for J-IMRT. The averaged mean laryngeal dose was 18 Gy with both techniques. The averaged mean doses within the matchline volumes were 69.3 Gy for WF-MRT and 66.2 Gy for J-IMRT (p = 0.03). The WF-IMRT technique appears to offer an optimal coverage of the target volumes and a mean dose to the larynx similar with J-IMRT and should be further evaluated in clinical trials.

  17. Working memory capacity and visual-verbal cognitive load modulate auditory-sensory gating in the brainstem: toward a unified view of attention.

    Sörqvist, Patrik; Stenfelt, Stefan; Rönnberg, Jerker

    2012-11-01

    Two fundamental research questions have driven attention research in the past: One concerns whether selection of relevant information among competing, irrelevant, information takes place at an early or at a late processing stage; the other concerns whether the capacity of attention is limited by a central, domain-general pool of resources or by independent, modality-specific pools. In this article, we contribute to these debates by showing that the auditory-evoked brainstem response (an early stage of auditory processing) to task-irrelevant sound decreases as a function of central working memory load (manipulated with a visual-verbal version of the n-back task). Furthermore, individual differences in central/domain-general working memory capacity modulated the magnitude of the auditory-evoked brainstem response, but only in the high working memory load condition. The results support a unified view of attention whereby the capacity of a late/central mechanism (working memory) modulates early precortical sensory processing.

  18. Semantic and Syntactic Associations During Word Search Modulate the Relationship Between Attention and Subsequent Memory.

    Zhou, Wei; Mo, Fei; Zhang, Yunhong; Ding, Jinhong

    2017-01-01

    Two experiments were conducted to investigate how linguistic information influences attention allocation in visual search and memory for words. In Experiment 1, participants searched for the synonym of a cue word among five words. The distractors included one antonym and three unrelated words. In Experiment 2, participants were asked to judge whether the five words presented on the screen comprise a valid sentence. The relationships among words were sentential, semantically related or unrelated. A memory recognition task followed. Results in both experiments showed that linguistically related words produced better memory performance. We also found that there were significant interactions between linguistic relation conditions and memorization on eye-movement measures, indicating that good memory for words relied on frequent and long fixations during search in the unrelated condition but to a much lesser extent in linguistically related conditions. We conclude that semantic and syntactic associations attenuate the link between overt attention allocation and subsequent memory performance, suggesting that linguistic relatedness can somewhat compensate for a relative lack of attention during word search.

  19. Migration of interfacial oxygen ions modulated resistive switching in oxide-based memory devices

    Chen, C.; Gao, S.; Zeng, F.; Tang, G. S.; Li, S. Z.; Song, C.; Fu, H. D.; Pan, F.

    2013-07-01

    Oxides-based resistive switching memory induced by oxygen ions migration is attractive for future nonvolatile memories. Numerous works had focused their attentions on the sandwiched oxide materials for depressing the characteristic variations, but the comprehensive studies of the dependence of electrodes on the migration behavior of oxygen ions are overshadowed. Here, we investigated the interaction of various metals (Ni, Co, Al, Ti, Zr, and Hf) with oxygen atoms at the metal/Ta2O5 interface under electric stress and explored the effect of top electrode on the characteristic variations of Ta2O5-based memory device. It is demonstrated that chemically inert electrodes (Ni and Co) lead to the scattering switching characteristics and destructive gas bubbles, while the highly chemically active metals (Hf and Zr) formed a thick and dense interfacial intermediate oxide layer at the metal/Ta2O5 interface, which also degraded the resistive switching behavior. The relatively chemically active metals (Al and Ti) can absorb oxygen ions from the Ta2O5 film and avoid forming the problematic interfacial layer, which is benefit to the formation of oxygen vacancies composed conduction filaments in Ta2O5 film thus exhibit the minimum variations of switching characteristics. The clarification of oxygen ions migration behavior at the interface can lead further optimization of resistive switching performance in Ta2O5-based memory device and guide the rule of electrode selection for other oxide-based resistive switching memories.

  20. Modulation of recognition memory performance by light requires both melanopsin and classical photoreceptors

    Tam, Shu K. E.; Hasan, Sibah; Hughes, Steven; Hankins, Mark W.; Foster, Russell G.; Bannerman, David M.

    2016-01-01

    Acute light exposure exerts various effects on physiology and behaviour. Although the effects of light on brain network activity in humans are well demonstrated, the effects of light on cognitive performance are inconclusive, with the size, as well as direction, of the effect depending on the nature of the task. Similarly, in nocturnal rodents, bright light can either facilitate or disrupt performance depending on the type of task employed. Crucially, it is unclear whether the effects of light on behavioural performance are mediated via the classical image-forming rods and cones or the melanopsin-expressing photosensitive retinal ganglion cells. Here, we investigate the modulatory effects of light on memory performance in mice using the spontaneous object recognition task. Importantly, we examine which photoreceptors are required to mediate the effects of light on memory performance. By using a cross-over design, we show that object recognition memory is disrupted when the test phase is conducted under a bright light (350 lux), regardless of the light level in the sample phase (10 or 350 lux), demonstrating that exposure to a bright light at the time of test, rather than at the time of encoding, impairs performance. Strikingly, the modulatory effect of light on memory performance is completely abolished in both melanopsin-deficient and rodless–coneless mice. Our findings provide direct evidence that melanopsin-driven and rod/cone-driven photoresponses are integrated in order to mediate the effect of light on memory performance. PMID:28003454

  1. Effects of gamma-aminobutyric acid-modulating drugs on working memory and brain function in patients with schizophrenia.

    Menzies, Lara; Ooi, Cinly; Kamath, Shri; Suckling, John; McKenna, Peter; Fletcher, Paul; Bullmore, Ed; Stephenson, Caroline

    2007-02-01

    Cognitive impairment causes morbidity in schizophrenia and could be due to abnormalities of cortical interneurons using the inhibitory neurotransmitter gamma-aminobutyric acid (GABA). To test the predictions that cognitive and brain functional responses to GABA-modulating drugs are correlated and abnormal in schizophrenia. Pharmacological functional magnetic resonance imaging study of 2 groups, each undergoing scanning 3 times, using an N-back working memory task, after placebo, lorazepam, or flumazenil administration. Eleven patients with chronic schizophrenia were recruited from a rehabilitation service, and 11 healthy volunteers matched for age, sex, and premorbid IQ were recruited from the local community. Intervention Participants received 2 mg of oral lorazepam, a 0.9-mg intravenous flumazenil bolus followed by a flumazenil infusion of 0.0102 mg/min, or oral and intravenous placebo. Working memory performance was summarized by the target discrimination index at several levels of difficulty. Increasing (or decreasing) brain functional activation in response to increasing task difficulty was summarized by the positive (or negative) load response. Lorazepam impaired performance and flumazenil enhanced it; these cognitive effects were more salient in schizophrenic patients. Functional magnetic resonance imaging demonstrated positive load response in a frontoparietal system and negative load response in the temporal and posterior cingulate regions; activation of the frontoparietal cortex was positively correlated with deactivation of the temporocingulate cortex. After placebo administration, schizophrenic patients had abnormally attenuated activation of the frontoparietal cortex and deactivation of the temporocingulate cortex; this pattern was mimicked in healthy volunteers and exacerbated in schizophrenic patients by lorazepam. However, in schizophrenic patients, flumazenil enhanced deactivation of the temporocingulate and activation of the anterior cingulate

  2. Wide-band analog frequency modulation of optic signals using indirect techniques

    Fitzmartin, D. J.; Balboni, E. J.; Gels, R. G.

    1991-01-01

    The wideband frequency modulation (FM) of an optical carrier by a radio frequency (RF) or microwave signal can be accomplished independent of laser type when indirect modulation is employed. Indirect modulators exploit the integral relation of phase to frequency so that phase modulators can be used to impress frequency modulation on an optical carrier. The use of integrated optics phase modulators, which are highly linear, enables the generation of optical wideband FM signals with very low intermodulation distortion. This modulator can be used as part of an optical wideband FM link for RF and microwave signals. Experimental results from the test of an indirect frequency modulator for an optical carrier are discussed.

  3. Nuclear Technology. Course 32: Nondestructive Examination (NDE) Techniques II. Module 32-4, Operation of Magnetic Particle Test Equipment.

    Groseclose, Richard

    This fourth in a series of six modules for a course titled Nondestructive Examination (NDE) Techniques II describes the specific technique variables and options which are available to the test technician, provides instructions for selecting and operating the appropriate test equipment, describes physical criteria for detectable discontinuities,…

  4. Reward anticipation modulates the effect of stress-related increases in cortisol on episodic memory.

    Quent, Jörn A; McCullough, Andrew M; Sazma, Matt; Wolf, Oliver T; Yonelinas, Andrew P

    2018-01-01

    When acute stress is experienced shortly after an event is encoded into memory, this can slow the forgetting of the study event, which is thought to reflect the effect of cortisol on consolidation. In addition, when events are encoded under conditions of high reward they tend to be remembered better than those encoded under non-rewarding conditions, and these effects are thought to reflect the operation of the dopaminergic reward system. Although both modulatory systems are believed to impact the medial temporal lobe regions critical for episodic memory, the manner, and even the extent, to which these two systems interact is currently unknown. To address this question in the current study, participants encoded words under reward or non-reward conditions, then one half of the participants were stressed using the social evaluation cold pressor task and the other half completed a non-stress control task. After a two-hour delay, all participants received a free recall and recognition memory test. There were no significant effects of stress or reward on overall memory performance. However, for the non-reward items, increases in stress-related cortisol in stressed participants were related to increases in recall and increases in recollection-based recognition responses. In contrast, for the reward items, increases in stress-related cortisol were not related to increases in memory performance. The results indicate that the stress and the reward systems interact in the way they impact episodic memory. The results are consistent with tag and capture models in the sense that cortisol reactivity can only affect non-reward items because plasticity-related products are already provided by reward anticipation. Copyright © 2017 Elsevier Inc. All rights reserved.

  5. Changes in auditory memory performance following the use of frequency-modulated system in children with suspected auditory processing disorders.

    Umat, Cila; Mukari, Siti Z; Ezan, Nurul F; Din, Normah C

    2011-08-01

    To examine the changes in the short-term auditory memory following the use of frequency-modulated (FM) system in children with suspected auditory processing disorders (APDs), and also to compare the advantages of bilateral over unilateral FM fitting. This longitudinal study involved 53 children from Sekolah Kebangsaan Jalan Kuantan 2, Kuala Lumpur, Malaysia who fulfilled the inclusion criteria. The study was conducted from September 2007 to October 2008 in the Department of Audiology and Speech Sciences, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia. The children's age was between 7-10 years old, and they were assigned into 3 groups: 15 in the control group (not fitted with FM); 19 in the unilateral; and 19 in the bilateral FM-fitting group. Subjects wore the FM system during school time for 12 weeks. Their working memory (WM), best learning (BL), and retention of information (ROI) were measured using the Rey Auditory Verbal Learning Test at pre-fitting, post (after 12 weeks of FM usage), and at long term (one year after the usage of FM system ended). There were significant differences in the mean WM (p=0.001), BL (p=0.019), and ROI (p=0.005) scores at the different measurement times, in which the mean scores at long-term were consistently higher than at pre-fitting, despite similar performances at the baseline (p>0.05). There was no significant difference in performance between unilateral- and bilateral-fitting groups. The use of FM might give a long-term effect on improving selected short-term auditory memories of some children with suspected APDs. One may not need to use 2 FM receivers to receive advantages on auditory memory performance.

  6. The effect of non-visual working memory load on top-down modulation of visual processing.

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

    2009-06-01

    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 task-relevant and irrelevant visual representations. In our dual-task paradigm, each trial began with the auditory presentation of six random (high load) or sequentially ordered (low load) digits. Next, two relevant visual stimuli (e.g., faces), presented amongst two temporally interspersed visual distractors (e.g., scenes), were to be encoded and maintained across a 7-s delay interval, after which memory for the relevant images and digits was probed. When taxed by high load digit maintenance, participants exhibited impaired performance on the visual WM task and a selective failure to attenuate the neural processing of task-irrelevant scene stimuli. The over-processing of distractor scenes under high load was indexed by elevated encoding activity in a scene-selective region-of-interest relative to low load and passive viewing control conditions, as well as by improved long-term recognition memory for these items. In contrast, the load manipulation did not affect participants' ability to upregulate activity in this region when scenes were task-relevant. These results highlight the critical role of domain-general WM resources in the goal-directed regulation of distractor processing. Moreover, the consequences of increased WM load in young adults closely resemble the effects of cognitive aging on distractor filtering [Gazzaley, A., Cooney, J. W., Rissman, J., & D'Esposito, M. (2005). Top-down suppression deficit underlies working memory impairment in normal aging. Nature Neuroscience 8, 1298-1300], suggesting the possibility of a common underlying mechanism.

  7. Short-term sleep deprivation impairs spatial working memory and modulates expression levels of ionotropic glutamate receptor subunits in hippocampus.

    Xie, Meilan; Yan, Jie; He, Chao; Yang, Li; Tan, Gang; Li, Chao; Hu, Zhian; Wang, Jiali

    2015-06-01

    Hippocampus-dependent learning memory is sensitive to sleep deprivation (SD). Although the ionotropic glutamate receptors play a vital role in synaptic plasticity and learning and memory, however, whether the expression of these receptor subunits is modulated by sleep loss remains unclear. In the present study, western blotting was performed by probing with specific antibodies against the ionotropic α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor subunits GluA1, GluA2, GluA3, and against the N-methyl-d-aspartate (NMDA) glutamate receptor subunits GluN1, GluN2A, GluN2B. In hippocampus, down regulation of surface GluA1 and GluN2A surface expression were observed in both SD groups. However, surface expression level of GluA2, GluA3, GluN1 and GluN2B was significantly up-regulated in 8h-SD rats when compared to the 4h-SD rats. In parallel with the complex changes in AMPA and NMDA receptor subunit expressions, we found the 8h-SD impaired rat spatial working memory in 30-s-delay T-maze task, whereas no impairment of spatial learning was observed in 4h-SD rats. These results indicate that sleep loss alters the relative expression levels of the AMPA and NMDA receptors, thus affects the synaptic strength and capacity for plasticity and partially contributes to spatial memory impairment. Copyright © 2015. Published by Elsevier B.V.

  8. Modulation of learning and memory by the targeted deletion of the circadian clock gene Bmal1 in forebrain circuits.

    Snider, Kaitlin H; Dziema, Heather; Aten, Sydney; Loeser, Jacob; Norona, Frances E; Hoyt, Kari; Obrietan, Karl

    2016-07-15

    A large body of literature has shown that the disruption of circadian clock timing has profound effects on mood, memory and complex thinking. Central to this time keeping process is the master circadian pacemaker located within the suprachiasmatic nucleus (SCN). Of note, within the central nervous system, clock timing is not exclusive to the SCN, but rather, ancillary oscillatory capacity has been detected in a wide range of cell types and brain regions, including forebrain circuits that underlie complex cognitive processes. These observations raise questions about the hierarchical and functional relationship between the SCN and forebrain oscillators, and, relatedly, about the underlying clock-gated synaptic circuitry that modulates cognition. Here, we utilized a clock knockout strategy in which the essential circadian timing gene Bmal1 was selectively deleted from excitatory forebrain neurons, whilst the SCN clock remained intact, to test the role of forebrain clock timing in learning, memory, anxiety, and behavioral despair. With this model system, we observed numerous effects on hippocampus-dependent measures of cognition. Mice lacking forebrain Bmal1 exhibited deficits in both acquisition and recall on the Barnes maze. Notably, loss of forebrain Bmal1 abrogated time-of-day dependent novel object location memory. However, the loss of Bmal1 did not alter performance on the elevated plus maze, open field assay, and tail suspension test, indicating that this phenotype specifically impairs cognition but not affect. Together, these data suggest that forebrain clock timing plays a critical role in shaping the efficiency of learning and memory retrieval over the circadian day. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Dopamine D1 sensitivity in the prefrontal cortex predicts general cognitive abilities and is modulated by working memory training.

    Wass, Christopher; Pizzo, Alessandro; Sauce, Bruno; Kawasumi, Yushi; Sturzoiu, Tudor; Ree, Fred; Otto, Tim; Matzel, Louis D

    2013-10-15

    A common source of variance (i.e., "general intelligence") underlies an individual's performance across diverse tests of cognitive ability, and evidence indicates that the processing efficacy of working memory may serve as one such source of common variance. One component of working memory, selective attention, has been reported to co-vary with general intelligence, and dopamine D1 signaling in prefrontal cortex can modulate attentional abilities. Based on their aggregate performance across five diverse tests of learning, here we characterized the general cognitive ability (GCA) of CD-1 outbred mice. In response to a D1 agonist (SKF82958, 1 mg/kg), we then assessed the relationship between GCA and activation of D1 receptor (D1R)-containing neurons in the prelimbic region of the medial prefrontal cortex, the agranular insular cortex, and the dorsomedial striatum. Increased activation of D1R-containing neurons in the prelimbic cortex (but not the agranular insular cortex or dorsomedial striatum) was observed in animals of high GCA relative to those of low GCA (quantified by c-Fos activation in response to the D1 agonist). However, a Western blot analysis revealed no differences in the density of D1Rs in the prelimbic cortex between animals of high and low GCA. Last, it was observed that working memory training promoted an increase in animals' GCA and enhanced D1R-mediated neuronal activation in the prelimbic cortex. These results suggest that the sensitivity (but not density) of D1Rs in the prelimbic cortex may both regulate GCA and be a target for working memory training.

  10. Modulation format identification enabled by the digital frequency-offset loading technique for hitless coherent transceiver.

    Fu, Songnian; Xu, Zuying; Lu, Jianing; Jiang, Hexun; Wu, Qiong; Hu, Zhouyi; Tang, Ming; Liu, Deming; Chan, Calvin Chun-Kit

    2018-03-19

    We propose a blind and fast modulation format identification (MFI) enabled by the digital frequency-offset (FO) loading technique for hitless coherent transceiver. Since modulation format information is encoded to the FO distribution during digital signal processing (DSP) at the transmitter side (Tx), we can use the fast Fourier transformation based FO estimation (FFT-FOE) method to obtain the FO distribution of individual data block after constant modulus algorithm (CMA) pre-equalization at the receiver side, in order to realize non-data-aided (NDA) and fast MFI. The obtained FO can be also used for subsequent FO compensation (FOC), without additional complexity. We numerically investigate and experimentally verify the proposed MFI with high accuracy and fast format switching among 28 Gbaud dual-polarization (DP)-4/8/16/64QAM, time domain hybrid-4/16QAM, and set partitioning (SP)-128QAM. In particular, the proposed MFI brings no performance degradation, in term of tolerance of amplified spontaneous emission (ASE) noise, laser linewidth, and fiber nonlinearity. Finally, a hitless coherent transceiver enabled by the proposed MFI with switching-block of only 2048 symbols is demonstrated over 1500 km standard single mode fiber (SSMF) transmission.

  11. General Time-Division AltBOC Modulation Technique for GNSS Signals

    Z. Zhou

    2018-04-01

    Full Text Available In this paper, a general time-division alternate binary offset carrier (GTD-AltBOC modulation method is proposed, which is an extension of TD-AltBOC and time-multiplexed offset-carrier quadrature phase shift keying (TMOC-QPSK with high design flexibility. In this method, binary complex subcarriers and a time-division technique with flexible time slot assignment are used to achieve constant envelope modulation of the signal components with a variable power allocation ratio (PAR. The underlying principle of GTD-AltBOC and the constraints related to the PAR are investigated. For the generation of GTD-AltBOC signals, a lookup table (LUT-based scheme is presented; the minimum required clock rate is half or less of that for existing non-time-division methods. The receiver processing complexities are analyzed for three typical receiving modes, and the power spectral densities (PSDs, cross-correlation functions, multiplexing efficiencies and code-tracking performance are simulated; the results show that GTD-AltBOC enables a significant decrease in receiving complexity compared with existing methods while maintaining high performance in terms of multiplexing efficiency and code tracking.

  12. Control and Modulation Techniques for a Centralized PV Generation System Grid Connected via an Interleaved Inverter

    Gianluca Brando

    2016-09-01

    Full Text Available In the context of grid connected photovoitaic (PV generation systems, there are two paramount aspects regarding the Maximum Power Point Tracking (MPPT of the photovoltaic units and the continuity of the service. The most diffused MPPT algorithms are based on either perturb and observe, or on an incremental conductance approach and need both PV current and voltage measurements. Several topology reconfigurable converters are also associated with the PV plants, guaranteeing fault-tolerant features. The generation continuity can also be assured by interleaved inverters, which keep the system operating at reduced maximum power in case of failure. In this paper, an evolution of a hysteresis based MPPT algorithm is presented, based on the measurement of only one voltage, together with a novel space vector modulation suitable for a two-channel three-phase grid connected interleaved inverter. The proposed MMPT algorithm and modulation technique are tested by means of several numerical analyses on a PV generation system of about 200 kW maximum power. The results testify the validity of the proposed strategies, showing good performance, even during a fault occurrence and in the presence of deep shading conditions.

  13. Modulating the Optoelectronic Properties of Silver Nanowires Films: Effect of Capping Agent and Deposition Technique.

    Lopez-Diaz, D; Merino, C; Velázquez, M M

    2015-11-11

    Silver nanowires 90 nm in diameter and 9 µm in length have been synthesized using different capping agents: polyvinyl pyrrolidone (PVP) and alkyl thiol of different chain lengths. The nanowire structure is not influenced by the displacement of PVP by alkyl thiols, although alkyl thiols modify the lateral aggregation of nanowires. We examined the effect of the capping agent and the deposition method on the optical and electrical properties of films prepared by Spray and the Langmuir-Schaefer methodologies. Our results revealed that nanowires capped with PVP and C8-thiol present the best optoelectronic properties. By using different deposition techniques and by modifying the nanowire surface density, we can modulate the optoelectronic properties of films. This strategy allows obtaining films with the optoelectronic properties required to manufacture touch screens and electromagnetic shielding.

  14. Modulating the Optoelectronic Properties of Silver Nanowires Films: Effect of Capping Agent and Deposition Technique

    D. Lopez-Diaz

    2015-11-01

    Full Text Available Silver nanowires 90 nm in diameter and 9 µm in length have been synthesized using different capping agents: polyvinyl pyrrolidone (PVP and alkyl thiol of different chain lengths. The nanowire structure is not influenced by the displacement of PVP by alkyl thiols, although alkyl thiols modify the lateral aggregation of nanowires. We examined the effect of the capping agent and the deposition method on the optical and electrical properties of films prepared by Spray and the Langmuir-Schaefer methodologies. Our results revealed that nanowires capped with PVP and C8-thiol present the best optoelectronic properties. By using different deposition techniques and by modifying the nanowire surface density, we can modulate the optoelectronic properties of films. This strategy allows obtaining films with the optoelectronic properties required to manufacture touch screens and electromagnetic shielding.

  15. Input current interharmonics in adjustable speed drives caused by fixed-frequency modulation techniques

    Soltani, Hamid; Davari, Pooya; Loh, Poh Chiang

    2016-01-01

    Adjustable Speed Drives (ASDs) based on double-stage conversion systems may inject interharmonics distortion into the grid, other than the well-known characteristic harmonic components. The problems created by interharmonics make it necessary to find their precise sources, and, to adopt an approp......Adjustable Speed Drives (ASDs) based on double-stage conversion systems may inject interharmonics distortion into the grid, other than the well-known characteristic harmonic components. The problems created by interharmonics make it necessary to find their precise sources, and, to adopt...... an appropriate strategy for minimizing their effects. This paper investigates the ASD's input current interharmonic sources caused by applying symmetrical regularly sampled fixed-frequency modulation techniques on the inverter. The interharmonics generation process is precisely formulated and comparative results...

  16. Consolidation differentially modulates schema effects on memory for items and associations

    van Kesteren, Marlieke T R; Rijpkema, Mark; Ruiter, Dirk J; Fernández, Guillén

    2013-01-01

    Newly learned information that is congruent with a preexisting schema is often better remembered than information that is incongrSaveuent. This schema effect on memory has previously been associated to more efficient encoding and consolidation mechanisms. However, this effect is not always

  17. Consolidation differentially modulates schema effects on memory for items and associations

    Kesteren, M.T. van; Rijpkema, M.J.P.; Ruiter, D.J.; Fernandez, G.S.E.

    2013-01-01

    Newly learned information that is congruent with a preexisting schema is often better remembered than information that is incongruent. This schema effect on memory has previously been associated to more efficient encoding and consolidation mechanisms. However, this effect is not always consistently

  18. Noradrenergic activation of the basolateral amygdala modulates the consolidation of object-in-context recognition memory

    Barsegyan, Areg; McGaugh, James L.; Roozendaal, Benno

    2014-01-01

    Noradrenergic activation of the basolateral complex of the amygdala (BLA) is well known to enhance the consolidation of long-term memory of highly emotionally arousing training experiences. The present study investigated whether such noradrenergic activation of the BLA also influences the

  19. Modality-specific Alpha Modulations Facilitate Long-term Memory Encoding in the Presence of Distracters

    Jiang, H.; Gerven, M.A.J. van; Jensen, O.

    2015-01-01

    It has been proposed that long-term memory encoding is not only dependent on engaging task-relevant regions but also on disengaging task-irrelevant regions. In particular, oscillatory alpha activity has been shown to be involved in shaping the functional architecture of the working brain because it

  20. Modality-specific Alpha Modulations Facilitate Long-term Memory Encoding in the Presence of Distracters

    Jiang, H.; Gerven, M.A.J. van; Jensen, O.

    2014-01-01

    It has been proposed that long-term memory encoding is not only dependent on engaging task-relevant regions but also on disengaging task-irrelevant regions. In particular, oscillatory alpha activity has been shown to be involved in shaping the functional architecture of the working brain because it

  1. How experience modulates semantic memory for food: evidence from elderly adults and centenarians.

    Vignando, Miriam; Aiello, Marilena; Foroni, Francesco; Marcon, Gabriella; Tettamanti, Mauro; Rumiati, Raffaella I

    2018-04-24

    In order to make sense of the objects we encounter in everyday life we largely rely on previous knowledge stored in our semantic memory. Semantic memory is considered dependent on lifelong experience and cultural knowledge. So far, a few studies have investigated the role of expertise on the organization of semantic memory, whereas life-long experience has largely been overlooked. In this study, we investigated this issue using food concepts. In particular, we administered different semantic tasks using food (natural and transformed) and non-food (living and non-living things) as stimuli to participants belonging to three different age cohorts (56-74, 75-91, 100-108), who were also asked to report on the dietary habits held throughout their life. In addition, we investigated to what extent psycholinguistic variables influence the semantic performance of different age cohorts. Results showed that Centenarians recognized natural food better than transformed food, while the other two groups showed the opposite pattern. According to our analyses, experience is responsible for this effect in Centenarians, as their dietary habits seem to suggest. Moreover, significant correlations between picture naming and age of acquisition, familiarity and frequency were observed. This study indicates that lifelong experience can shape conceptual knowledge of food concepts, and that semantic memory is less resilient to aging than initially thought.

  2. Protecting visual short-term memory during maintenance : Attentional modulation of target and distractor representations

    Vissers, M.E.; Gulbinaite, R.; van den Bos, T.; Slagter, H.A.

    2017-01-01

    In the presence of distraction, attentional filtering is a key predictor of efficient information storage in visual short-term memory (VSTM). Yet, the role of attention in distractor filtering, and the extent to which attentional filtering continues to protect information during post-perceptual

  3. 16K CAMAC analyzer memory module for data acquisition with four ADCs with variable conversation gain

    Nagy, J.Z.

    1985-01-01

    This module containing 16 K . 24 bit CMOS RAM enables four measurements in spectrum or list mode simultaneously. In spectrum mode the RAM can be divided into four segments each in size between 1 and 16 K. (orig.)

  4. Olfaction, Emotion, and the Amygdala: arousal-dependent modulation of long-term autobiographical memory and its association with olfaction: beginning to unravel the Proust phenomenon?

    Mark Hughes

    2004-06-01

    Full Text Available The sense of smell is set apart from other sensory modalities. Odours possess the capacity to trigger immediately strong emotional memories. Moreover, odorous stimuli provide a higher degree of memory retention than other sensory stimuli. Odour perception, even in its most elemental form - olfaction - already involves limbic structures. This early involvement is not paralleled in other sensory modalities. Bearing in mind the considerable connectivity with limbic structures, and the fact that an activation of the amygdala is capable of instantaneously evoking emotions and facilitating the encoding of memories, it is unsurprising that the sense of smell has its characteristic nature. The aim of this review is to analyse current understanding of higher olfactory information processing as it relates to the ability of odours to spontaneously cue highly vivid, affectively toned, and often very old autobiographical memories (episodes known anecdotally as Proust phenomena. Particular emphasis is placed on the diversity of functions attributed to the amygdala. Its role in modulating the encoding and retrieval of long-term memory is investigated with reference to lesion, electrophysiological, immediate early gene, and functional imaging studies in both rodents and humans. Additionally, the influence of hormonal modulation and the adrenergic system on emotional memory storage is outlined. I finish by proposing a schematic of some of the critical neural pathways that underlie the odour-associated encoding and retrieval of emotionally toned autobiographical memories.

  5. Odor valence linearly modulates attractiveness, but not age assessment, of invariant facial features in a memory-based rating task.

    Seubert, Janina; Gregory, Kristen M; Chamberland, Jessica; Dessirier, Jean-Marc; Lundström, Johan N

    2014-01-01

    Scented cosmetic products are used across cultures as a way to favorably influence one's appearance. While crossmodal effects of odor valence on perceived attractiveness of facial features have been demonstrated experimentally, it is unknown whether they represent a phenomenon specific to affective processing. In this experiment, we presented odors in the context of a face battery with systematic feature manipulations during a speeded response task. Modulatory effects of linear increases of odor valence were investigated by juxtaposing subsequent memory-based ratings tasks--one predominantly affective (attractiveness) and a second, cognitive (age). The linear modulation pattern observed for attractiveness was consistent with additive effects of face and odor appraisal. Effects of odor valence on age perception were not linearly modulated and may be the result of cognitive interference. Affective and cognitive processing of faces thus appear to differ in their susceptibility to modulation by odors, likely as a result of privileged access of olfactory stimuli to affective brain networks. These results are critically discussed with respect to potential biases introduced by the preceding speeded response task.

  6. Alpha1-adrenergic receptor blockade in the VTA modulates fear memories and stress responses.

    Solecki, Wojciech B; Szklarczyk, Klaudia; Klasa, Adam; Pradel, Kamil; Dobrzański, Grzegorz; Przewłocki, Ryszard

    2017-08-01

    Activity of the ventral tegmental area (VTA) and its terminals has been implicated in the Pavlovian associative learning of both stressful and rewarding stimuli. However, the role of the VTA noradrenergic signaling in fear responses remains unclear. We aimed to examine how alpha 1 -adrenergic receptor (α 1 -AR) signaling in the VTA affects conditioned fear. The role of α 1 -AR was assessed using the micro-infusions into the VTA of the selective antagonists (0.1-1µg/0.5µl prazosin and 1µg/0.5µl terazosin) in acquisition and expression of fear memory. In addition, we performed control experiments with α 1 -AR blockade in the mammillary bodies (MB) - a brain region with α 1 -AR expression adjacent to the VTA. Intra-VTA but not intra-MB α 1 -AR blockade prevented formation and retrieval of fear memories. Importantly, local administration of α 1 -AR antagonists did not influence footshock sensitivity, locomotion or anxiety-like behaviors. Similarly, α 1 -AR blockade in the VTA had no effects on negative affect measured as number of 22kHz ultrasonic vocalizations during fear conditioning training. We propose that noradrenergic signaling in the VTA via α 1 -AR regulates formation and retrieval of fear memories but not other behavioral responses to stressful environmental stimuli. It enhances the encoding of environmental stimuli by the VTA to form and retrieve conditioned fear memories and to predict future behavioral outcomes. Our results provide novel insight into the role of the VTA α 1 -AR signaling in the regulation of stress responsiveness and fear memory. Copyright © 2017 Elsevier B.V. and ECNP. All rights reserved.

  7. Modulation of Autoimmune T-Cell Memory by Stem Cell Educator Therapy: Phase 1/2 Clinical Trial.

    Delgado, Elias; Perez-Basterrechea, Marcos; Suarez-Alvarez, Beatriz; Zhou, Huimin; Revuelta, Eva Martinez; Garcia-Gala, Jose Maria; Perez, Silvia; Alvarez-Viejo, Maria; Menendez, Edelmiro; Lopez-Larrea, Carlos; Tang, Ruifeng; Zhu, Zhenlong; Hu, Wei; Moss, Thomas; Guindi, Edward; Otero, Jesus; Zhao, Yong

    2015-12-01

    Type 1 diabetes (T1D) is a T cell-mediated autoimmune disease that causes a deficit of pancreatic islet β cells. The complexities of overcoming autoimmunity in T1D have contributed to the challenges the research community faces when devising successful treatments with conventional immune therapies. Overcoming autoimmune T cell memory represents one of the key hurdles. In this open-label, phase 1/phase 2 study, Caucasian T1D patients (N = 15) received two treatments with the Stem Cell Educator (SCE) therapy, an approach that uses human multipotent cord blood-derived multipotent stem cells (CB-SCs). SCE therapy involves a closed-loop system that briefly treats the patient's lymphocytes with CB-SCs in vitro and returns the "educated" lymphocytes (but not the CB-SCs) into the patient's blood circulation. This study is registered with ClinicalTrials.gov, NCT01350219. Clinical data demonstrated that SCE therapy was well tolerated in all subjects. The percentage of naïve CD4(+) T cells was significantly increased at 26 weeks and maintained through the final follow-up at 56 weeks. The percentage of CD4(+) central memory T cells (TCM) was markedly and constantly increased at 18 weeks. Both CD4(+) effector memory T cells (TEM) and CD8(+) TEM cells were considerably decreased at 18 weeks and 26 weeks respectively. Additional clinical data demonstrated the modulation of C-C chemokine receptor 7 (CCR7) expressions on naïve T, TCM, and TEM cells. Following two treatments with SCE therapy, islet β-cell function was improved and maintained in individuals with residual β-cell function, but not in those without residual β-cell function. Current clinical data demonstrated the safety and efficacy of SCE therapy in immune modulation. SCE therapy provides lasting reversal of autoimmune memory that could improve islet β-cell function in Caucasian subjects. Obra Social "La Caixa", Instituto de Salud Carlos III, Red de Investigación Renal, European Union FEDER Funds, Principado de

  8. Cavity Preparation/assembly Techniques and Impact on Q, Realistic Q - Factors in a Module, Review of Modules

    Peter Kneisel

    2005-03-19

    This contribution summarizes the surface preparation procedures for niobium cavities presently used both in laboratory experiments and for modules, such as buffered chemical polishing (BCP), electropolishing (EP), high pressure ultrapure water rinsing (HPR), CO{sub 2} snow cleaning and high temperature heat treatments for hydrogen degassing or postpurification. The impact of surface treatments and the degree of cleanliness during assembly procedures on cavity performance (Q - value and accelerating gradient E{sub acc}) will be discussed. In addition, an attempt will be made to summarize the experiences made in module assemblies in different labs/projects such as DESY(TTF), Jlab (Upgrade) and SNS.

  9. Dosimetric comparison of intensity modulated radiotherapy techniques and standard wedged tangents for whole breast radiotherapy

    Fong, Andrew; Bromley, Regina; Beat, Mardi; Vien, Din; Dineley, Jude; Morgan, Graeme

    2009-01-01

    Full text: Prior to introducing intensity modulated radiotherapy (IMRT) for whole breast radiotherapy (WBRT) into our department we undertook a comparison of the dose parameters of several IMRT techniques and standard wedged tangents (SWT). Our aim was to improve the dose distribution to the breast and to decrease the dose to organs at risk (OAR): heart, lung and contralateral breast (Contra Br). Treatment plans for 20 women (10 right-sided and 10 left-sided) previously treated with SWT for WBRT were used to compare (a) SWT; (b) electronic compensators IMRT (E-IMRT); (c) tangential beam IMRT (T-IMRT); (d) coplanar multi-field IMRT (CP-IMRT); and (e) non-coplanar multi-field IMRT (NCP-IMRT). Plans for the breast were compared for (i) dose homogeneity (DH); (ii) conformity index (CI); (iii) mean dose; (iv) maximum dose; (v) minimum dose; and dose to OAR were calculated (vi) heart; (vii) lung and (viii) Contra Br. Compared with SWT, all plans except CP-IMRT gave improvement in at least two of the seven parameters evaluated. T-IMRT and NCP-IMRT resulted in significant improvement in all parameters except DH and both gave significant reduction in doses to OAR. As on initial evaluation NCP-IMRT is likely to be too time consuming to introduce on a large scale, T-IMRT is the preferred technique for WBRT for use in our department.

  10. Differential immediate and sustained memory enhancing effects of alpha7 nicotinic receptor agonists and allosteric modulators in rats.

    Morten S Thomsen

    Full Text Available The α7 nicotinic acetylcholine receptor (nAChR is a potential target for the treatment of cognitive deficits in patients with schizophrenia, ADHD and Alzheimer's disease. Here we test the hypothesis that upregulation of α7 nAChR levels underlies the enhanced and sustained procognitive effect of repeated administration of α7 nAChR agonists. We further compare the effect of agonists to that of α7 nAChR positive allosteric modulators (PAMs, which do not induce upregulation of the α7 nAChR. Using the social discrimination test as a measure of short-term memory, we show that the α7 nAChR agonist A-582941 improves short-term memory immediately after repeated (7× daily, but not a single administration. The α7 nAChR PAMs PNU-120596 and AVL-3288 do not affect short-term memory immediately after a single or repeated administration. This demonstrates a fundamental difference in the behavioral effects of agonists and PAMs that may be relevant for clinical development. Importantly, A-582941 and AVL-3288 increase short-term memory 24 hrs after repeated, but not a single, administration, suggesting that repeated administration of both agonists and PAMs may produce sustained effects on cognitive performance. Subsequent [(125I]-bungarotoxin autoradiography revealed no direct correlation between α7 nAChR levels in frontal cortical or hippocampal brain regions and short-term memory with either compound. Additionally, repeated treatment with A-582941 did not affect mRNA expression of RIC-3 or the lynx-like gene products lynx1, lynx2, PSCA, or Ly6H, which are known to affect nAChR function. In conclusion, both α7 nAChR agonists and PAMs exhibit sustained pro-cognitive effects after repeated administration, and altered levels of the α7 nAChR per se, or that of endogenous regulators of nAChR function, are likely not the major cause of this effect.

  11. Working Memory Modulates Glutamate Levels in the Dorsolateral Prefrontal Cortex during 1H fMRS

    Eric A. Woodcock

    2018-03-01

    Full Text Available Glutamate is involved in excitatory neurotransmission and metabolic processes related to brain function. Previous studies using proton functional magnetic resonance spectroscopy (1H fMRS have demonstrated elevated cortical glutamate levels by 2–4% during visual and motor stimulation, relative to periods of no stimulation. Here, we extended this approach to working memory cognitive task performance, which has been consistently associated with dorsolateral prefrontal cortex (dlPFC activation. Sixteen healthy adult volunteers completed a continuous visual fixation “rest” task followed by a letter 2-back working memory task during 1H fMRS acquisition of the left dlPFC, which encompassed Brodmann areas 45 and 46 over a 4.5-cm3 volume. Using a 100% automated fitting procedure integrated with LCModel, raw spectra were eddy current-, phase-, and shift-corrected prior to quantification resulting in a 32s temporal resolution or 8 averages per spectra. Task compliance was high (95 ± 11% correct and the mean Cramer-Rao Lower Bound of glutamate was 6.9 ± 0.9%. Relative to continuous passive visual fixation, left dlPFC glutamate levels were significantly higher by 2.7% (0.32 mmol/kg wet weight during letter 2-back performance. Elevated dlPFC glutamate levels reflect increased metabolic activity and excitatory neurotransmission driven by working memory-related cognitive demands. These results provide the first in vivo demonstration of elevated dlPFC glutamate levels during working memory.

  12. Culture modulates implicit ownership-induced self-bias in memory.

    Sparks, Samuel; Cunningham, Sheila J; Kritikos, Ada

    2016-08-01

    The relation of incoming stimuli to the self implicitly determines the allocation of cognitive resources. Cultural variations in the self-concept shape cognition, but the extent is unclear because the majority of studies sample only Western participants. We report cultural differences (Asian versus Western) in ownership-induced self-bias in recognition memory for objects. In two experiments, participants allocated a series of images depicting household objects to self-owned or other-owned virtual baskets based on colour cues before completing a surprise recognition memory test for the objects. The 'other' was either a stranger or a close other. In both experiments, Western participants showed greater recognition memory accuracy for self-owned compared with other-owned objects, consistent with an independent self-construal. In Experiment 1, which required minimal attention to the owned objects, Asian participants showed no such ownership-related bias in recognition accuracy. In Experiment 2, which required attention to owned objects to move them along the screen, Asian participants again showed no overall memory advantage for self-owned items and actually exhibited higher recognition accuracy for mother-owned than self-owned objects, reversing the pattern observed for Westerners. This is consistent with an interdependent self-construal which is sensitive to the particular relationship between the self and other. Overall, our results suggest that the self acts as an organising principle for allocating cognitive resources, but that the way it is constructed depends upon cultural experience. Additionally, the manifestation of these cultural differences in self-representation depends on the allocation of attentional resources to self- and other-associated stimuli. Crown Copyright © 2016. Published by Elsevier B.V. All rights reserved.

  13. Transcranial direct current stimulation may modulate extinction memory in posttraumatic stress disorder

    van?t Wout, Mascha; Longo, Sharon M.; Reddy, Madhavi K.; Philip, Noah S.; Bowker, Marguerite T.; Greenberg, Benjamin D.

    2017-01-01

    Abstract Background Abnormalities in fear extinction and recall are core components of posttraumatic stress disorder (PTSD). Data from animal and human studies point to a role of the ventromedial prefrontal cortex (vmPFC) in extinction learning and subsequent retention of extinction memories. Given the increasing interest in developing noninvasive brain stimulation protocols for psychopathology treatment, we piloted whether transcranial direct current stimulation (tDCS) during extinction lear...

  14. Unilateral prefrontal direct current stimulation effects are modulated by working memory load and gender.

    Meiron, Oded; Lavidor, Michal

    2013-05-01

    Recent studies revealed that anodal transcranial direct current stimulation (tDCS) to the left dorsolateral prefrontal cortex (DLPFC) may improve verbal working memory (WM) performance in humans. In the present study, we evaluated executive attention, which is the core of WM capacity, considered to be significantly involved in tasks that require active maintenance of memory representations in interference-rich conditions, and is highly dependent on DLPFC function. We investigated verbal WM accuracy using a WM task that is highly sensitive to executive attention function. We were interested in how verbal WM accuracy may be affected by WM load, unilateral DLPFC stimulation, and gender, as previous studies showed gender-dependent brain activation during verbal WM tasks. We utilized a modified verbal n-Back task hypothesized to increase demands on executive attention. We examined "online" WM performance while participants received transcranial direct current stimulation (tDCS), and implicit learning performance in a post-stimulation WM task. Significant lateralized "online" stimulation effects were found only in the highest WM load condition revealing that males benefit from left DLPFC stimulation, while females benefit from right DLPFC stimulation. High WM load performance in the left DLPFC stimulation was significantly related to post-stimulation recall performance. Our findings support the idea that lateralized stimulation effects in high verbal WM load may be gender-dependent. Further, our post-stimulation results support the idea that increased left hemisphere activity may be important for encoding verbal information into episodic memory as well as for facilitating retrieval of context-specific targets from semantic memory. Copyright © 2013 Elsevier Inc. All rights reserved.

  15. IoT security with one-time pad secure algorithm based on the double memory technique

    Wiśniewski, Remigiusz; Grobelny, Michał; Grobelna, Iwona; Bazydło, Grzegorz

    2017-11-01

    Secure encryption of data in Internet of Things is especially important as many information is exchanged every day and the number of attack vectors on IoT elements still increases. In the paper a novel symmetric encryption method is proposed. The idea bases on the one-time pad technique. The proposed solution applies double memory concept to secure transmitted data. The presented algorithm is considered as a part of communication protocol and it has been initially validated against known security issues.

  16. Modulation of network excitability by persistent activity: how working memory affects the response to incoming stimuli.

    Elisa M Tartaglia

    2015-02-01

    Full Text Available Persistent activity and match effects are widely regarded as neuronal correlates of short-term storage and manipulation of information, with the first serving active maintenance and the latter supporting the comparison between memory contents and incoming sensory information. The mechanistic and functional relationship between these two basic neurophysiological signatures of working memory remains elusive. We propose that match signals are generated as a result of transient changes in local network excitability brought about by persistent activity. Neurons more active will be more excitable, and thus more responsive to external inputs. Accordingly, network responses are jointly determined by the incoming stimulus and the ongoing pattern of persistent activity. Using a spiking model network, we show that this mechanism is able to reproduce most of the experimental phenomenology of match effects as exposed by single-cell recordings during delayed-response tasks. The model provides a unified, parsimonious mechanistic account of the main neuronal correlates of working memory, makes several experimentally testable predictions, and demonstrates a new functional role for persistent activity.

  17. Does emotion modulate the efficacy of spaced learning in recognition memory?

    Nicola Mammarella

    2014-12-01

    Full Text Available Memory for repeated items improves when presentations are spaced during study. Here, two experiments assessed the so-called spacing effect on a yes–no recognition memory task using affective and neutral words. In Experiment 1, a group of participants was asked to orient their attention to semantic features of target words (deep semantic analysis that were consecutively repeated or spaced, while another group was engaged in a graphemic shallow analysis of words (Experiment 2. The depth of word processing approach was meant to highlight the role of repetition priming mechanisms in the generation of spacing effects. We found that spacing effects occurred for both affective and neutral words (Experiment 1. However, following shallow analysis of words, the spacing effect was reduced for both affective and neutral words (Experiment 2. No differences were detected in terms of positive versus negative words. These results suggest that spaced learning operates when the to-be-remembered material is also affectively charged and that, under certain circumstances, it may enhance recognition memory as affective connotation does.

  18. Acute cannabinoids impair working memory through astroglial CB1 receptor modulation of hippocampal LTD.

    Han, Jing; Kesner, Philip; Metna-Laurent, Mathilde; Duan, Tingting; Xu, Lin; Georges, Francois; Koehl, Muriel; Abrous, Djoher Nora; Mendizabal-Zubiaga, Juan; Grandes, Pedro; Liu, Qingsong; Bai, Guang; Wang, Wei; Xiong, Lize; Ren, Wei; Marsicano, Giovanni; Zhang, Xia

    2012-03-02

    Impairment of working memory is one of the most important deleterious effects of marijuana intoxication in humans, but its underlying mechanisms are presently unknown. Here, we demonstrate that the impairment of spatial working memory (SWM) and in vivo long-term depression (LTD) of synaptic strength at hippocampal CA3-CA1 synapses, induced by an acute exposure of exogenous cannabinoids, is fully abolished in conditional mutant mice lacking type-1 cannabinoid receptors (CB(1)R) in brain astroglial cells but is conserved in mice lacking CB(1)R in glutamatergic or GABAergic neurons. Blockade of neuronal glutamate N-methyl-D-aspartate receptors (NMDAR) and of synaptic trafficking of glutamate α-amino-3-hydroxy-5-methyl-isoxazole propionic acid receptors (AMPAR) also abolishes cannabinoid effects on SWM and LTD induction and expression. We conclude that the impairment of working memory by marijuana and cannabinoids is due to the activation of astroglial CB(1)R and is associated with astroglia-dependent hippocampal LTD in vivo. Copyright © 2012 Elsevier Inc. All rights reserved.

  19. IGF-I Gene Therapy in Aging Rats Modulates Hippocampal Genes Relevant to Memory Function.

    Pardo, Joaquín; Abba, Martin C; Lacunza, Ezequiel; Ogundele, Olalekan M; Paiva, Isabel; Morel, Gustavo R; Outeiro, Tiago F; Goya, Rodolfo G

    2018-03-14

    In rats, learning and memory performance decline during normal aging, which makes this rodent species a suitable model to evaluate therapeutic strategies. In aging rats, insulin-like growth factor-I (IGF-I), is known to significantly improve spatial memory accuracy as compared to control counterparts. A constellation of gene expression changes underlie the hippocampal phenotype of aging but no studies on the effects of IGF-I on the hippocampal transcriptome of old rodents have been documented. Here, we assessed the effects of IGF-I gene therapy on spatial memory performance in old female rats and compared them with changes in the hippocampal transcriptome. In the Barnes maze test, experimental rats showed a significantly higher exploratory frequency of the goal hole than controls. Hippocampal RNA-sequencing showed that 219 genes are differentially expressed in 28-month-old rats intracerebroventricularly injected with an adenovector expressing rat IGF-I as compared with placebo adenovector-injected counterparts. From the differentially expressed genes, 81 were down and 138 upregulated. From those genes, a list of functionally relevant genes, concerning hippocampal IGF-I expression, synaptic plasticity as well as neuronal function was identified. Our results provide an initial glimpse at the molecular mechanisms underlying the neuroprotective actions of IGF-I in the aging brain.

  20. Urtica dioica modulates hippocampal insulin signaling and recognition memory deficit in streptozotocin induced diabetic mice.

    Patel, Sita Sharan; Gupta, Sahil; Udayabanu, Malairaman

    2016-06-01

    Diabetes mellitus has been associated with functional abnormalities in the hippocampus and performance of cognitive function. Urtica dioica (UD) has been used in the treatment of diabetes. In our previous report we observed that UD extract attenuate diabetes mediated associative and spatial memory dysfunction. The present study aimed to evaluate the effect of UD extract on mouse model of diabetes-induced recognition memory deficit and explore the possible mechanism behind it. Streptozotocin (STZ) (50 mg/kg, i.p. consecutively for 5 days) was used to induce diabetes followed by UD extract (50 mg/kg, oral) or rosiglitazone (ROSI) (5 mg/kg, oral) administration for 8 weeks. STZ induced diabetic mice showed significant decrease in hippocampal insulin signaling and translocation of glucose transporter type 4 (GLUT4) to neuronal membrane resulting in cognitive dysfunction and hypolocomotion. UD treatment effectively improved hippocampal insulin signaling, glucose tolerance and recognition memory performance in diabetic mice, which was comparable to ROSI. Further, diabetes mediated oxidative stress and inflammation was reversed by chronic UD or ROSI administration. UD leaves extract acts via insulin signaling pathway and might prove to be effective for the diabetes mediated central nervous system complications.

  1. A Deletion Variant of the α2b-Adrenoceptor Modulates the Stress-Induced Shift from "Cognitive" to "Habit" Memory.

    Wirz, Lisa; Wacker, Jan; Felten, Andrea; Reuter, Martin; Schwabe, Lars

    2017-02-22

    Stress induces a shift from hippocampus-based "cognitive" toward dorsal striatum-based "habitual" learning and memory. This shift is thought to have important implications for stress-related psychopathologies, including post-traumatic stress disorder (PTSD). However, there is large individual variability in the stress-induced bias toward habit memory, and the factors underlying this variability are completely unknown. Here we hypothesized that a functional deletion variant of the gene encoding the α2b-adrenoceptor ( ADRA2B ), which has been linked to emotional memory processes and increased PTSD risk, modulates the stress-induced shift from cognitive toward habit memory. In two independent experimental studies, healthy humans were genotyped for the ADRA2B deletion variant. After a stress or control manipulation, participants completed a dual-solution learning task while electroencephalographic (Study I) or fMRI measurements (Study II) were taken. Carriers compared with noncarriers of the ADRA2B deletion variant exhibited a significantly reduced bias toward habit memory after stress. fMRI results indicated that, whereas noncarriers of the ADRA2B deletion variant showed increased functional connectivity between amygdala and putamen after stress, this increase in connectivity was absent in carriers of the deletion variant, who instead showed overall enhanced connectivity between amygdala and entorhinal cortex. Our results indicate that a common genetic variation of the noradrenergic system modulates the impact of stress on the balance between cognitive and habitual memory systems, most likely via altered amygdala orchestration of these systems. SIGNIFICANCE STATEMENT Stressful events have a powerful effect on human learning and memory. Specifically, accumulating evidence suggests that stress favors more rigid dorsal striatum-dependent habit memory, at the expense of flexible hippocampus-dependent cognitive memory. Although this shift may have important implications

  2. Cardiac avoidance in breast radiotherapy: a comparison of simple shielding techniques with intensity-modulated radiotherapy

    Landau, David; Adams, Elizabeth J.; Webb, Steve; Ross, Gillian

    2001-01-01

    Background and purpose: Adjuvant breast radiotherapy (RT) is now part of the routine care of patients with early breast cancer. However, analysis of the Early Breast Cancer Trialists' Collaborative suggests that patients with the lowest risk of dying of breast cancer are at significant risk of cardiac mortality due to longer relapse-free survival. Patients with a significant amount of heart in the high-dose volume have been shown to be at risk of fatal cardiac events. This study was designed to assess whether conformal planning or intensity-modulated radiotherapy (IMRT) techniques allow reduced cardiac irradiation whilst maintaining full target coverage. Material and methods: Ten patients with early breast cancer were available for computed tomography (CT) planning. Each had at least 1 cm maximum heart depth within the posterior border of conventional tangents. For each patient, plans were generated and compared using dose volume histograms for planning target volume (PTV) and organs at risk. The plans included conventional tangents with and without shielding. The shielding was designed to either completely spare the heart or to shield as much heart as possible without compromising PTV coverage. IMRT plans were also prepared using two- and four-field tangential and six-field arc-like beam arrangements. Results: PTV homogeneity was better for the tangential IMRT techniques. For all patients, cardiac irradiation was reduced by the addition of partial cardiac shielding to conventional tangents, without compromise of PTV coverage. The two- and four-field IMRT techniques also reduced heart doses. The average percentage volume of heart receiving >60% of the prescription dose was 4.4% (range 1.0-7.1%) for conventional tangents, 1.5% (0.2-3.9%) for partial shielding, 2.3% (0.5-4.6%) for the two-field IMRT technique and 2.2% (0.4-5.6%) for the four-field IMRT technique. For patients with larger maximum heart depths the four-field IMRT plan achieved greater heart sparing

  3. The FCMM, a Fastbus Control and Memory Module for readout of the DELPHI SAT track detector

    Wikne, J.C.; Skaali, B.

    1990-02-01

    The Small Angle Tagger (SAT) in the DELPHI experiment at CERN concists of detector units placed close to the beam on both sides of the interaction point. The track detector part of the SAT is built of Si-strip detectors where position can be measured to an accurancy of 1 mm in the radial direction. A specially developed Fastbus module for reading and front end buffering of the data from the track detector is decribed in the report. The description is intended as a complete technical manual for the module. 13 refs.; 27 figs

  4. Novel security enhancement technique against eavesdropper for OCDMA system using 2-D modulation format with code switching scheme

    Singh, Simranjit; Kaur, Ramandeep; Singh, Amanvir; Kaler, R. S.

    2015-03-01

    In this paper, security of the spectrally encoded-optical code division multiplexed access (OCDMA) system is enhanced by using 2-D (orthogonal) modulation technique. This is an effective approach for simultaneous improvement of the system capacity and security. Also, the results show that the hybrid modulation technique proved to be a better option to enhance the data confidentiality at higher data rates using minimum utilization of bandwidth in a multiuser environment. Further, the proposed system performance is compared with the current state-of-the-art OCDMA schemes.

  5. A novel oscillation control for MEMS vibratory gyroscopes using a modified electromechanical amplitude modulation technique

    Ma, Wei; Lin, Yiyu; Liu, Siqi; Zheng, Xudong; Jin, Zhonghe

    2017-01-01

    This paper reports a novel oscillation control algorithm for MEMS vibratory gyroscopes using a modified electromechanical amplitude modulation (MEAM) technique, which enhances the robustness against the frequency variation of the driving mode, compared to the conventional EAM (CEAM) scheme. In this approach, the carrier voltage exerted on the proof mass is frequency-modulated by the drive resonant frequency. Accordingly, the pick-up signal from the interface circuit involves a constant-frequency component that contains the amplitude and phase information of the vibration displacement. In other words, this informational detection signal is independent of the mechanical resonant frequency, which varies due to different batches, imprecise micro-fabrication and changing environmental temperature. In this paper, the automatic gain control loop together with the phase-locked loop are simultaneously analyzed using the averaging method and Routh–Hurwitz criterion, deriving the stability condition and the parameter optimization rules of the transient response. Then, a simulation model based on the real system is set up to evaluate the control algorithm. Further, the proposed MEAM method is tested using a field-programmable-gate-array based digital platform on a capacitive vibratory gyroscope. By optimizing the control parameters, the transient response of the drive amplitude reveals a settling time of 45.2 ms without overshoot, according well with the theoretical prediction and simulation results. The first measurement results show that the amplitude variance of the drive displacement is 12 ppm in an hour while the phase standard deviation is as low as 0.0004°. The mode-split gyroscope operating under atmospheric pressure demonstrates an outstanding performance. By virtue of the proposed MEAM method, the bias instability and angle random walk are measured to be 0.9° h −1 (improved by 2.4 times compared to the CEAM method) and 0.068° (√h) −1 (improved by 1

  6. The Number of Genomic Copies at the 16p11.2 Locus Modulates Language, Verbal Memory, and Inhibition.

    Hippolyte, Loyse; Maillard, Anne M; Rodriguez-Herreros, Borja; Pain, Aurélie; Martin-Brevet, Sandra; Ferrari, Carina; Conus, Philippe; Macé, Aurélien; Hadjikhani, Nouchine; Metspalu, Andres; Reigo, Anu; Kolk, Anneli; Männik, Katrin; Barker, Mandy; Isidor, Bertrand; Le Caignec, Cédric; Mignot, Cyril; Schneider, Laurence; Mottron, Laurent; Keren, Boris; David, Albert; Doco-Fenzy, Martine; Gérard, Marion; Bernier, Raphael; Goin-Kochel, Robin P; Hanson, Ellen; Green Snyder, LeeAnne; Ramus, Franck; Beckmann, Jacques S; Draganski, Bogdan; Reymond, Alexandre; Jacquemont, Sébastien

    2016-07-15

    Deletions and duplications of the 16p11.2 BP4-BP5 locus are prevalent copy number variations (CNVs), highly associated with autism spectrum disorder and schizophrenia. Beyond language and global cognition, neuropsychological assessments of these two CNVs have not yet been reported. This study investigates the relationship between the number of genomic copies at the 16p11.2 locus and cognitive domains assessed in 62 deletion carriers, 44 duplication carriers, and 71 intrafamilial control subjects. IQ is decreased in deletion and duplication carriers, but we demonstrate contrasting cognitive profiles in these reciprocal CNVs. Deletion carriers present with severe impairments of phonology and of inhibition skills beyond what is expected for their IQ level. In contrast, for verbal memory and phonology, the data may suggest that duplication carriers outperform intrafamilial control subjects with the same IQ level. This finding is reminiscent of special isolated skills as well as contrasting language performance observed in autism spectrum disorder. Some domains, such as visuospatial and working memory, are unaffected by the 16p11.2 locus beyond the effect of decreased IQ. Neuroimaging analyses reveal that measures of inhibition covary with neuroanatomic structures previously identified as sensitive to 16p11.2 CNVs. The simultaneous study of reciprocal CNVs suggests that the 16p11.2 genomic locus modulates specific cognitive skills according to the number of genomic copies. Further research is warranted to replicate these findings and elucidate the molecular mechanisms modulating these cognitive performances. Copyright © 2016 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

  7. Radio Frequency Identification (RFID) in medical environment: Gaussian Derivative Frequency Modulation (GDFM) as a novel modulation technique with minimal interference properties.

    Rieche, Marie; Komenský, Tomás; Husar, Peter

    2011-01-01

    Radio Frequency Identification (RFID) systems in healthcare facilitate the possibility of contact-free identification and tracking of patients, medical equipment and medication. Thereby, patient safety will be improved and costs as well as medication errors will be reduced considerably. However, the application of RFID and other wireless communication systems has the potential to cause harmful electromagnetic disturbances on sensitive medical devices. This risk mainly depends on the transmission power and the method of data communication. In this contribution we point out the reasons for such incidents and give proposals to overcome these problems. Therefore a novel modulation and transmission technique called Gaussian Derivative Frequency Modulation (GDFM) is developed. Moreover, we carry out measurements to show the inteference properties of different modulation schemes in comparison to our GDFM.

  8. A Comparison of Potential IM-CW Lidar Modulation Techniques for ASCENDS CO2 Column Measurements From Space

    Campbell, Joel F.; Lin, Bing; Nehrir, Amin R.; Harrison, F. Wallace; Obland, Michael D.; Ismail, Syed

    2014-01-01

    Global atmospheric carbon dioxide (CO2) measurements through the Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) Decadal Survey recommended space mission are critical for improving our understanding of CO2 sources and sinks. IM-CW (Intensity Modulated Continuous Wave) lidar techniques are investigated as a means of facilitating CO2 measurements from space to meet the ASCENDS science requirements. In previous laboratory and flight experiments we have successfully used linear swept frequency modulation to discriminate surface lidar returns from intermediate aerosol and cloud contamination. Furthermore, high accuracy and precision ranging to the surface as well as to the top of intermediate clouds, which is a requirement for the inversion of the CO2 column-mixing ratio from the instrument optical depth measurements, has been demonstrated with the linear swept frequency modulation technique. We are concurrently investigating advanced techniques to help improve the auto-correlation properties of the transmitted waveform implemented through physical hardware to make cloud rejection more robust in special restricted scenarios. Several different carrier based modulation techniques are compared including orthogonal linear swept, orthogonal non-linear swept, and Binary Phase Shift Keying (BPSK). Techniques are investigated that reduce or eliminate sidelobes. These techniques have excellent auto-correlation properties while possessing a finite bandwidth (by way of a new cyclic digital filter), which will reduce bias error in the presence of multiple scatterers. Our analyses show that the studied modulation techniques can increase the accuracy of CO2 column measurements from space. A comparison of various properties such as signal to noise ratio (SNR) and time-bandwidth product are discussed.

  9. DREADD in parvalbumin interneurons of the dentate gyrus modulates anxiety, social interaction and memory extinction.

    Zou, D; Chen, L; Deng, D; Jiang, D; Dong, F; McSweeney, C; Zhou, Y; Liu, L; Chen, G; Wu, Y; Mao, Y

    2016-01-01

    Parvalbumin (PV)-positive interneurons in the hippocampus play a critical role in animal memory, such as spatial working memory. However, how PV-positive interneurons in the subregions of the hippocampus affect animal behaviors remains poorly defined. Here, we achieved specific and reversible activation of PV-positive interneurons using designer receptors exclusively activated by designer drugs (DREADD) technology. Inducible DREADD expression was demonstrated in vitro in cultured neurons, in which co-transfection of the hM3D-Gq-mCherry vector with a Cre plasmid resulted in a cellular response to hM3Dq ligand clozapine-N-oxide (CNO) stimulation. In addition, the dentate gyrus (DG) of PV-Cre mice received bilateral injection of control lentivirus or lentivirus expressing double floxed hM3D-Gq-mCherry. Selective activation of PV-positive interneurons in the DG did not affect locomotor activity or depression-related behavior in mice. Interestingly, stimulation of PV-positive interneurons induced an anxiolytic effect. Activation of PVpositive interneurons appears to impair social interaction to novelty, but has no effect on social motivation. However, this defect is likely due to the anxiolytic effect as the exploratory behavior of mice expressing hM3DGq is significantly increased. Mice expressing hM3D-Gq did not affect novel object recognition. Activation of PV-positive interneurons in the DG maintains intact cued and contextual fear memory but facilitates fear extinction. Collectively, our results demonstrated that proper control of PV interneurons activity in the DG is critical for regulation of the anxiety, social interaction and fear extinction. These results improve our fundamental understanding of the physiological role of PV-positive interneurons in the hippocampus.

  10. Space Vector Modulation Technique to Reduce Leakage Current of a Transformerless Three-Phase Four-Leg Photovoltaic System

    F. Hasanzad

    2017-06-01

    Full Text Available Photovoltaic systems integrated to the grid have received considerable attention around the world. They can be connected to the electrical grid via galvanic isolation (transformer or without it (transformerless. Despite making galvanic isolation, low frequency transformer increases size, cost and losses. On the other hand, transformerless PV systems increase the leakage current (common-mode current, (CMC through the parasitic capacitors of the PV array. Inverter topology and switching technique are the most important parameters the leakage current depends on. As there is no need to extra hardware for switching scheme modification, it's an economical method for reducing leakage current. This paper evaluates the effect of different space vector modulation techniques on leakage current for a two-level three-phase four-leg inverter used in PV system. It proposes an efficient space vector modulation method which decreases the leakage current to below the quantity specified in VDE-0126-1-1 standard. furthermore, some other characteristics of the space vector modulation schemes that have not been significantly discussed for four-leg inverter, are considered, such as, modulation index, switching actions per period, common-mode voltage (CMV, and total harmonic distortion (THD. An extend software simulation using MATLAB/Simulink is performed to verify the effectiveness of the modulation technique.

  11. Supramodal Theta, Gamma, and Sustained Fields Predict Modality-specific Modulations of Alpha and Beta Oscillations during Visual and Tactile Working Memory.

    van Ede, Freek; Jensen, Ole; Maris, Eric

    2017-08-01

    Flexible control over currently relevant sensory representations is an essential feature of primate cognition. We investigated the neurophysiological bases of such flexible control in humans during an intermodal working memory task in which participants retained visual or tactile sequences. Using magnetoencephalography, we first show that working memory retention engages early visual and somatosensory areas, as reflected in the sustained load-dependent suppression of alpha and beta oscillations. Next, we identify three components that are also load dependent but modality independent: medial prefrontal theta synchronization, frontoparietal gamma synchronization, and sustained parietal event-related fields. Critically, these domain-general components predict (across trials and within load conditions) the modality-specific suppression of alpha and beta oscillations, with largely unique contributions per component. Thus, working memory engages multiple complementary frontoparietal components that have discernible neuronal dynamics and that flexibly modulate retention-related activity in sensory areas in a manner that tracks the current contents of working memory.

  12. The catechol-O-methyltransferase (COMT) Val158Met genotype modulates working memory-related dorsolateral prefrontal response and performance in bipolar disorder

    Miskowiak, K. W.; Kjærstad, H. L.; Støttrup, M. M.

    2017-01-01

    prefrontal cortex (dlPFC) (P=.016). Exploratory whole-brain analysis revealed a bilateral decrease in working memory-related dlPFC activity in the ValVal group vs the ValMet group which was not associated with differences in working memory performance during fMRI. Outside the MRI scanner, Val carriers...... performed worse in the CANTAB Spatial Working Memory task than Met homozygotes (P≤.006), with deficits being most pronounced in Val homozygotes. CONCLUSIONS: The association between Val allelic load, dlPFC activity and WM impairment points to a putative role of aberrant PFC dopamine tonus in the cognitive......-O-methyltransferase (COMT) gene is associated with reduced prefrontal cortex dopamine and exaggerated working memory-related prefrontal activity. This functional magnetic resonance imaging (fMRI) study investigated for the first time whether the COMT Val158Met genotype modulates prefrontal activity during spatial working...

  13. Optically stimulated luminescence from quartz measured using the linear modulation technique

    Bulur, E.; Boetter-Jensen, L.; Murray, A.S.

    2000-01-01

    The optically stimulated luminescence (OSL) from heated natural quartz has been investigated using the linear modulation technique (LMT), in which the excitation light intensity is increased linearly during stimulation. In contrast to conventional stimulation, which usually produces a monotonically decreasing signal, linearly increasing the stimulation power gives peaks in the signal as a function of time. In cases where the OSL signal contains more than one component, the linear increase in power of the stimulation light may result in a curve containing overlapping peaks, where the most easily stimulated component occurs at a shorter time. This allows the separation of the overlapping OSL components, which are assumed to originate from different traps. The LM-OSL curve from quartz shows an initial peak followed by a broad one. Deconvolution using curve fitting has shown that the composite OSL curve from quartz can be approximated well by using a linear combination of first-order peaks. In addition to the three known components, i.e. fast, medium and slow components from continuous-wave-OSL studies, an additional slow component is also identified for the first time. The dose responses and thermal stabilities of the various components are also studied

  14. Modulated Magnetic Nanowires for Controlling Domain Wall Motion: Toward 3D Magnetic Memories

    Ivanov, Yurii P.; Chuvilin, Andrey; Lopatin, Sergei; Kosel, Jü rgen

    2016-01-01

    Cylindrical magnetic nanowires are attractive materials for next generation data storage devices owing to the theoretically achievable high domain wall velocity and their efficient fabrication in highly dense arrays. In order to obtain control over domain wall motion, reliable and well-defined pinning sites are required. Here, we show that modulated nanowires consisting of alternating nickel and cobalt sections facilitate efficient domain wall pinning at the interfaces of those sections. By combining electron holography with micromagnetic simulations, the pinning effect can be explained by the interaction of the stray fields generated at the interface and the domain wall. Utilizing a modified differential phase contrast imaging, we visualized the pinned domain wall with a high resolution, revealing its three-dimensional vortex structure with the previously predicted Bloch point at its center. These findings suggest the potential of modulated nanowires for the development of high-density, three-dimensional data storage devices. © 2016 American Chemical Society.

  15. Modulated Magnetic Nanowires for Controlling Domain Wall Motion: Toward 3D Magnetic Memories

    Ivanov, Yurii P.

    2016-05-03

    Cylindrical magnetic nanowires are attractive materials for next generation data storage devices owing to the theoretically achievable high domain wall velocity and their efficient fabrication in highly dense arrays. In order to obtain control over domain wall motion, reliable and well-defined pinning sites are required. Here, we show that modulated nanowires consisting of alternating nickel and cobalt sections facilitate efficient domain wall pinning at the interfaces of those sections. By combining electron holography with micromagnetic simulations, the pinning effect can be explained by the interaction of the stray fields generated at the interface and the domain wall. Utilizing a modified differential phase contrast imaging, we visualized the pinned domain wall with a high resolution, revealing its three-dimensional vortex structure with the previously predicted Bloch point at its center. These findings suggest the potential of modulated nanowires for the development of high-density, three-dimensional data storage devices. © 2016 American Chemical Society.

  16. Controlled Enhancemnt of Long-Term Memory by Modulating Neuronal miRNA Function

    2012-09-20

    Faraday Ave. Carlsbad CA 92008 Prepare antisense oligonucleotides 8/1/2007 12:00:00AM 2/1/2009 12:00:00AM Sub Contractor Numbers (c): Patent Clause...with ampakines. However, ampakines that accomplish positive modulation have shown undesired clinical side effects . Another approach is to improve...of times that a mouse touches objects introduced into the cage in a fixed period of time. Objects are either “old” (prior exposure) or “new” (not

  17. In vivo modulation of foreign body response on polyurethane by surface entrapment technique.

    Khandwekar, Anand P; Patil, Deepak P; Hardikar, Anand A; Shouche, Yogesh S; Doble, Mukesh

    2010-11-01

    Implanted polymeric materials, such as medical devices, provoke the body to initiate an inflammatory reaction, known as the foreign body response (FBR), which causes several complications. In this study, polyurethane (Tecoflex®, PU) surface modified with the nonionic surfactant Tween80® (PU/T80) and the cell adhesive PLL-RGD peptide (PU/PLL-RGD) by a previously described entrapment technique were implanted in the peritoneal cavity of Wistar rats for 30 days. Implants were retrieved and examined for tissue reactivity and cellular adherence by various microscopic and analytical techniques. Surface-induced inflammatory response was assessed by real-time PCR based quantification of proinflammatory cytokine transcripts, namely, TNF-α and IL-1β, normalized to housekeeping gene GAPDH. Cellular adherence and their distribution profile were assessed by microscopic examination of H&E stained implant sections. It was observed that PU/PLL-RGD followed by the bare PU surface exhibited severe inflammatory and fibrotic response with an average mean thickness of 19 and 12 μm, respectively, in 30 days. In contrast, PU/T80 surface showed only a cellular monolayer of 2-3 μm in thickness, with a mild inflammatory response and no fibrotic encapsulation. The PU/PLL-RGD peptide-modified substrate promoted an enhanced rate of macrophage cell fusion to form foreign body giant cell (FBGCs), whereas FBGCs were rarely observed on Tween80®-modified substrate. The expression levels of proinflammatory cytokines (TNF-α and IL-1β) were upregulated on PU/PLL-RGD surface followed by bare PU, whereas the cytokine expressions were significantly suppressed on PU/T80 surface. Thus, our study highlights modulation of foreign body response on polyurethane surfaces through surface entrapment technique in the form of differential responses observed on PLL-RGD and Tween80® modified surfaces with the former effective in triggering tissue cell adhesion thereby fibrous encapsulation, while the later

  18. Modulating epigenetic memory through vitamins and TET: implications for regenerative medicine and cancer treatment.

    Hore, Timothy A

    2017-06-01

    Vitamins A and C represent unrelated sets of small molecules that are essential to the human diet and have recently been shown to intensify erasure of epigenetic memory in naive embryonic stem cells. These effects are driven by complementary enhancement of the ten-eleven translocation (TET) demethylases - vitamin A stimulates TET expression, whereas vitamin C potentiates TET catalytic activity. Vitamin A and C cosupplementation synergistically enhances reprogramming of differentiated cells to the naive state, but overuse may exaggerate instability of imprinted genes. As such, optimizing their use in culture media will be important for regenerative medicine and mammalian transgenics. In addition, mechanistic perception of how these vitamins interact with the epigenome may be relevant for understanding cancer and improving patient treatment.

  19. Effects of perceptual and semantic cues on ERP modulations associated with prospective memory.

    Cousens, Ross; Cutmore, Timothy; Wang, Ya; Wilson, Jennifer; Chan, Raymond C K; Shum, David H K

    2015-10-01

    Prospective memory involves the formation and execution of intended actions and is essential for autonomous living. In this study (N=32), the effect of the nature of PM cues (semantic versus perceptual) on established event-related potentials (ERPs) elicited in PM tasks (N300 and prospective positivity) was investigated. PM cues defined by their perceptual features clearly elicited the N300 and prospective positivity whereas PM cues defined by semantic relatedness elicited prospective positivity. This calls into question the view that the N300 is a marker of general processes underlying detection of PM cues, but supports existing research showing that prospective positivity represents general post-retrieval processes that follow detection of PM cues. Continued refinement of ERP paradigms for understanding the neural correlates of PM is needed. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. Task relevance modulates successful retrieval effects during explicit and implicit memory tests.

    Elman, Jeremy A; Shimamura, Arthur P

    2011-05-01

    The successful retrieval effect refers to greater activation for items identified as old compared to those identified as new. This effect is particularly apparent in the ventral posterior parietal cortex (vPPC), though its functional properties remain unclear. In two experiments, we assessed the activation for old and new items during explicit and implicit tests of memory. In Experiment 1, significant effects were observed during explicit recognition performance and during an implicit lexical decision task. In both tasks, determining mnemonic status provides relevant information to task goals. Experiment 2 included a second implicit task in which determining mnemonic status was not relevant (color discrimination task). In this case, vPPC activation did not distinguish between old and new items. These findings suggest that automatic or implicit processes can drive retrieval-related activation in the vPPC, though such processes are gated by stimulus relevancy and task goals. Copyright © 2011 Elsevier Inc. All rights reserved.

  1. Modulation of the storage of social recognition memory by neurotransmitter systems in the insular cortex.

    Cavalcante, Lorena E S; Zinn, Carolina G; Schmidt, Scheila D; Saenger, Bruna F; Ferreira, Flávia F; Furini, Cristiane R G; Myskiw, Jociane C; Izquierdo, Ivan

    2017-09-15

    The insular cortex (IC) receives projections from prefrontal, entorhinal and cingulate cortex, olfactory bulb and basal nuclei and has reciprocal connections with the amygdala and entorhinal cortex. These connections suggest a possible involvement in memory processes; this has been borne out by data on several behaviors. Social recognition memory (SRM) is essential to form social groups and to establish hierarchies and social and affective ties. Despite its importance, knowledge about the brain structures and the neurotransmitter mechanisms involved in its processing is still scarce. Here we study the participation of NMDA-glutamatergic, D1/D5-dopaminergic, H2-histaminergic, β-adrenergic and 5-HT 1A -serotoninergic receptors of the IC in the consolidation of SRM. Male Wistar rats received intra-IC infusions of substances acting on these receptors immediately after the sample phase of a social discrimination task and 24h later were exposed to a 5-min retention test. The intra-IC infusion of antagonists of D1/D5, β-adrenergic or 5-HT 1A receptors immediately after the sample phase impaired the consolidation of SRM. These effects were blocked by the concomitant intra-IC infusion of agonists of these receptors. Antagonists and agonists of NMDA and H2 receptors had no effect on SRM. The results suggest that the dopaminergic D1/D5, β-adrenergic and serotonergic 5-HT 1A receptors in the IC, but not glutamatergic NMDA and the histaminergic H2 receptors, participate in the consolidation of SRM in the IC. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Insulin modulates hippocampally-mediated spatial working memory via glucose transporter-4.

    Pearson-Leary, J; Jahagirdar, V; Sage, J; McNay, E C

    2018-02-15

    The insulin-regulated glucose transporter, GluT4, is a key molecule in peripheral insulin signaling. Although GluT4 is abundantly expressed in neurons of specific brain regions such as the hippocampus, the functional role of neuronal GluT4 is unclear. Here, we used pharmacological inhibition of GluT4-mediated glucose uptake to determine whether GluT4 mediates insulin-mediated glucose uptake in the hippocampus. Consistent with previous reports, we found that glucose utilization increased in the dorsal hippocampus of male rats during spontaneous alternation (SA), a hippocampally-mediated spatial working memory task. We previously showed that insulin signaling within the hippocampus is required for processing this task, and that administration of exogenous insulin enhances performance. At baseline levels of hippocampal insulin, inhibition of GluT4-mediated glucose uptake did not affect SA performance. However, inhibition of an upstream regulator of GluT4, Akt, did impair SA performance. Conversely, when a memory-enhancing dose of insulin was delivered to the hippocampus prior to SA-testing, inhibition of GluT4-mediated glucose transport prevented cognitive enhancement. These data suggest that baseline hippocampal cognitive processing does not require functional hippocampal GluT4, but that cognitive enhancement by supra-baseline insulin does. Consistent with these findings, we found that in neuronal cell culture, insulin increases glucose utilization in a GluT4-dependent manner. Collectively, these data demonstrate a key role for GluT4 in transducing the procognitive effects of elevated hippocampal insulin. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Resource-sharing between internal maintenance and external selection modulates attentional capture by working memory content

    Anastasia eKiyonaga

    2014-08-01

    Full Text Available It is unclear why and under what circumstances working memory (WM and attention interact. Here, we apply the logic of the time-based resource-sharing (TBRS model of WM (e.g., Barrouillet, Bernardin, & Camos, 2004 to explore the mixed findings of a separate, but related, literature that studies the guidance of visual attention by WM contents. Specifically, we hypothesize that the linkage between WM representations and visual attention is governed by a time-shared cognitive resource that alternately refreshes internal (WM and selects external (visual attention information. If this were the case, WM content should guide visual attention (involuntarily, but only when there is time for it to be refreshed in an internal focus of attention. To provide an initial test for this hypothesis, we examined whether the amount of unoccupied time during a WM delay could impact the magnitude of attentional capture by WM contents. Participants were presented with a series of visual search trials while they maintained a WM cue for a delayed-recognition test. WM cues could coincide with the search target, a distracter, or neither. We varied both the number of searches to be performed, and the amount of available time to perform them. Slowing of visual search by a WM matching distracter—and facilitation by a matching target—were curtailed when the delay was filled with fast-paced (refreshing-preventing search trials, as was subsequent memory probe accuracy. WM content may, therefore, only capture visual attention when it can be refreshed, suggesting that internal (WM and external attention demands reciprocally impact one another because they share a limited resource. The TBRS rationale can thus be applied in a novel context to explain why WM contents capture attention, and under what conditions that effect should be observed.

  4. Novelty-induced emotional arousal modulates cannabinoid effects on recognition memory and adrenocortical activity.

    Campolongo, Patrizia; Morena, Maria; Scaccianoce, Sergio; Trezza, Viviana; Chiarotti, Flavia; Schelling, Gustav; Cuomo, Vincenzo; Roozendaal, Benno

    2013-06-01

    Although it is well established that cannabinoid drugs can influence cognitive performance, the findings-describing both enhancing and impairing effects-have been ambiguous. Here, we investigated the effects of posttraining systemic administration of the synthetic cannabinoid agonist WIN55,212-2 (0.1, 0.3, or 1.0 mg/kg) on short- and long-term retention of object recognition memory under two conditions that differed in their training-associated arousal level. In male Sprague-Dawley rats that were not previously habituated to the experimental context, WIN55,212-2 administered immediately after a 3-min training trial, biphasically impaired retention performance at a 1-h interval. In contrast, WIN55,212-2 enhanced 1-h retention of rats that had received extensive prior habituation to the experimental context. Interestingly, immediate posttraining administration of WIN55,212-2 to non-habituated rats, in doses that impaired 1-h retention, enhanced object recognition performance at a 24-h interval. Posttraining WIN55,212-2 administration to habituated rats did not significantly affect 24-h retention. In light of intimate interactions between cannabinoids and the hypothalamic-pituitary-adrenal axis, we further investigated whether cannabinoid administration might differently influence training-induced glucocorticoid activity in rats in these two habituation conditions. WIN55,212-2 administered after object recognition training elevated plasma corticosterone levels in non-habituated rats whereas it decreased corticosterone levels in habituated rats. Most importantly, following pretreatment with the corticosterone-synthesis inhibitor metyrapone, WIN55,212-2 effects on 1- and 24-h retention of non-habituated rats became similar to those seen in the low-aroused habituated animals, indicating that cannabinoid-induced regulation of adrenocortical activity contributes to the environmentally sensitive effects of systemically administered cannabinoids on short- and long

  5. Top down modulation of attention to food cues via working memory.

    Higgs, Suzanne; Rutters, Femke; Thomas, Jason M; Naish, Katherine; Humphreys, Glyn W

    2012-08-01

    Attentional biases towards food cues may be linked to the development of obesity. The present study investigated the mechanisms underlying attentional biases to food cues by assessing the role of top down influences, such as working memory (WM). We assessed whether attention in normal-weight, sated participants was drawn to food items specifically when that food item was held in WM. Twenty-three participants (15 f/8 m, age 23.4±5 year, BMI 23.5±4 kg/m(2)) took part in a laboratory based study assessing reaction times to food and non-food stimuli. Participants were presented with an initial cue stimulus to either hold in WM or to merely attend to, and then searched for the target (a circle) in a two-item display. On valid trials the target was flanked by a picture matching the cue, on neutral trials the display did not contain a picture matching the cue, and on invalid trials the distractor (a square) was flanked by a picture matching the cue. Cues were food, cars or stationery items. We observed that, relative to the effects with non-food stimuli, food items in WM strongly affected attention when the memorised cue re-appeared in the search display. In particular there was an enhanced response on valid trials, when the re-appearance of the memorised cue coincided with the search target. There were no effects of cue category on attentional guidance when the cues were merely attended to but not held in WM. These data point towards food having a strong effect on top-down guidance of search from working memory, and suggest a mechanism whereby individuals who are preoccupied with thoughts of food, for example obese individuals, show facilitated detection of food cues in the environment. Copyright © 2012 Elsevier Ltd. All rights reserved.

  6. The selective positive allosteric M1 muscarinic receptor modulator PQCA attenuates learning and memory deficits in the Tg2576 Alzheimer's disease mouse model.

    Puri, Vanita; Wang, Xiaohai; Vardigan, Joshua D; Kuduk, Scott D; Uslaner, Jason M

    2015-01-01

    We have recently shown that the M1 muscarinic receptor positive allosteric modulator, PQCA, improves cognitive performance in rodents and non-human primates administered the muscarinic receptor antagonist scopolamine. The purpose of the present experiments was to characterize the effects of PQCA in a model more relevant to the disease pathology of Alzheimer's disease. Tg2576 transgenic mice that have elevated Aβ were tested in the novel object recognition task to characterize recognition memory as a function of age and treatment with the PQCA. The effects of PQCA were compared to the acetylcholinesterase inhibitor donepezil, the standard of care for Alzheimer's disease. In addition, the effect of co-administering PQCA and donepezil was evaluated. Aged Tg2576 mice demonstrated a deficit in recognition memory that was significantly attenuated by PQCA. The positive control donepezil also reversed the deficit. Furthermore, doses of PQCA and donepezil that were inactive on their own were found to improve recognition memory when given together. These studies suggest that M1 muscarinic receptor positive allosteric modulation can ameliorate memory deficits in disease relevant models of Alzheimer's disease. These data, combined with our previous findings demonstrating PQCA improves scopolamine-induced cognitive deficits in both rodents and non-human primates, suggest that M1 positive allosteric modulators have therapeutic potential for the treatment of Alzheimer's disease. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. Organizational/Memory Tools: A Technique for Improving Problem Solving Skills.

    Steinberg, Esther R.; And Others

    1986-01-01

    This study was conducted to determine whether students would use a computer-presented organizational/memory tool as an aid in problem solving, and whether and how locus of control would affect tool use and problem-solving performance. Learners did use the tools, which were most effective in the learner control with feedback condition. (MBR)

  8. System and technique for retrieving depth information about a surface by projecting a composite image of modulated light patterns

    Hassebrook, Laurence G. (Inventor); Lau, Daniel L. (Inventor); Guan, Chun (Inventor)

    2010-01-01

    A technique, associated system and program code, for retrieving depth information about at least one surface of an object, such as an anatomical feature. Core features include: projecting a composite image comprising a plurality of modulated structured light patterns, at the anatomical feature; capturing an image reflected from the surface; and recovering pattern information from the reflected image, for each of the modulated structured light patterns. Pattern information is preferably recovered for each modulated structured light pattern used to create the composite, by performing a demodulation of the reflected image. Reconstruction of the surface can be accomplished by using depth information from the recovered patterns to produce a depth map/mapping thereof. Each signal waveform used for the modulation of a respective structured light pattern, is distinct from each of the other signal waveforms used for the modulation of other structured light patterns of a composite image; these signal waveforms may be selected from suitable types in any combination of distinct signal waveforms, provided the waveforms used are uncorrelated with respect to each other. The depth map/mapping to be utilized in a host of applications, for example: displaying a 3-D view of the object; virtual reality user-interaction interface with a computerized device; face--or other animal feature or inanimate object--recognition and comparison techniques for security or identification purposes; and 3-D video teleconferencing/telecollaboration.

  9. Olfactory memory is enhanced in mice exposed to extremely low-frequency electromagnetic fields via Wnt/β-catenin dependent modulation of subventricular zone neurogenesis.

    Mastrodonato, Alessia; Barbati, Saviana Antonella; Leone, Lucia; Colussi, Claudia; Gironi, Katia; Rinaudo, Marco; Piacentini, Roberto; Denny, Christine A; Grassi, Claudio

    2018-01-10

    Exposure to extremely low-frequency electromagnetic fields (ELFEF) influences the expression of key target genes controlling adult neurogenesis and modulates hippocampus-dependent memory. Here, we assayed whether ELFEF stimulation affects olfactory memory by modulating neurogenesis in the subventricular zone (SVZ) of the lateral ventricle, and investigated the underlying molecular mechanisms. We found that 30 days after the completion of an ELFEF stimulation protocol (1 mT; 50 Hz; 3.5 h/day for 12 days), mice showed enhanced olfactory memory and increased SVZ neurogenesis. These effects were associated with upregulated expression of mRNAs encoding for key regulators of adult neurogenesis and were mainly dependent on the activation of the Wnt pathway. Indeed, ELFEF stimulation increased Wnt3 mRNA expression and nuclear localization of its downstream target β-catenin. Conversely, inhibition of Wnt3 by Dkk-1 prevented ELFEF-induced upregulation of neurogenic genes and abolished ELFEF's effects on olfactory memory. Collectively, our findings suggest that ELFEF stimulation increases olfactory memory via enhanced Wnt/β-catenin signaling in the SVZ and point to ELFEF as a promising tool for enhancing SVZ neurogenesis and olfactory function.

  10. Modulating the Focus of Attention for Spoken Words at Encoding Affects Frontoparietal Activation for Incidental Verbal Memory

    Christensen, Thomas A.; Almryde, Kyle R.; Fidler, Lesley J.; Lockwood, Julie L.; Antonucci, Sharon M.; Plante, Elena

    2012-01-01

    Attention is crucial for encoding information into memory, and current dual-process models seek to explain the roles of attention in both recollection memory and incidental-perceptual memory processes. The present study combined an incidental memory paradigm with event-related functional MRI to examine the effect of attention at encoding on the subsequent neural activation associated with unintended perceptual memory for spoken words. At encoding, we systematically varied attention levels as ...

  11. High throughput techniques for discovering new glycine receptor modulators and their binding sites

    Daniel F Gilbert

    2009-10-01

    Full Text Available The inhibitory glycine receptor (GlyR is a member of the Cys-loop receptor family that mediates inhibitory neurotransmission in the central nervous system. These receptors are emerging as potential drug targets for inflammatory pain, immunomodulation, spasticity and epilepsy. Antagonists that specifically inhibit particular GlyR isoforms are also required as pharmacological probes for elucidating the roles of particular GlyR isoforms in health and disease. Although a substantial number of both positive and negative GlyR modulators have been identified, very few of these are specific for the GlyR over other receptor types. Thus, the potential of known compounds as either therapeutic leads or pharmacological probes is limited. It is therefore surprising that there have been few published studies describing attempts to discover novel GlyR isoform-specific compounds. The first aim of this review is to consider various methods for efficiently screening compounds against these receptors. We conclude that an anion sensitive yellow fluorescent protein is optimal for primary screening and that automated electrophysiology of cells stably expressing GlyRs is useful for confirming hits and quantitating the actions of identified compounds. The second aim of this review is to demonstrate how these techniques are used in our laboratory for the purpose of both discovering novel GlyR-active compounds and characterizing their binding sites. We also describe a reliable, cost effective method for transfecting HEK293 cells in single wells of a 384 well plate using nanogram quantities of cDNA.

  12. Analysis and Minimization of Output Current Ripple for Discontinuous Pulse-Width Modulation Techniques in Three-Phase Inverters

    Gabriele Grandi

    2016-05-01

    Full Text Available This paper gives the complete analysis of the output current ripple in three-phase voltage source inverters considering the different discontinuous pulse-width modulation (DPWM strategies. In particular, peak-to-peak current ripple amplitude is analytically evaluated over the fundamental period and compared among the most used DPWMs, including positive and negative clamped (DPWM+ and DPWM−, and the four possible combinations between them, usually named as DPWM0, DPWM1, DPWM2, and DPWM3. The maximum and the average values of peak-to-peak current ripple are estimated, and a simple method to correlate the ripple envelope with the ripple rms is proposed and verified. Furthermore, all the results obtained by DPWMs are compared to the centered pulse-width modulation (CPWM, equivalent to the space vector modulation to identify the optimal pulse-width modulation (PWM strategy as a function of the modulation index, taking into account the different average switching frequency. In this way, the PWM technique providing for the minimum output current ripple is identified over the whole modulation range. The analytical developments and the main results are experimentally verified by current ripple measurements with a three-phase PWM inverter prototype supplying an induction motor load.

  13. FPGA Techniques Based New Hybrid Modulation Strategies for Voltage Source Inverters

    Sudha, L. U.; Baskaran, J.; Elankurisil, S. A.

    2015-01-01

    This paper corroborates three different hybrid modulation strategies suitable for single-phase voltage source inverter. The proposed method is formulated using fundamental switching and carrier based pulse width modulation methods. The main tale of this proposed method is to optimize a specific performance criterion, such as minimization of the total harmonic distortion (THD), lower order harmonics, switching losses, and heat losses. The proposed method is articulated using fundamental switching and carrier based pulse width modulation methods. Thus, the harmonic pollution in the power system will be reduced and the power quality will be augmented with better harmonic profile for a target fundamental output voltage. The proposed modulation strategies are simulated in MATLAB r2010a and implemented in a Xilinx spartan 3E-500 FG 320 FPGA processor. The feasibility of these modulation strategies is authenticated through simulation and experimental results. PMID:25821852

  14. Polarization-sensitive surface plasmon enhanced ellipsometry biosensor using the photoelastic modulation technique

    Yuan, Scott Wu; Ho, Ho Pui; Wu, S.Y.

    2009-01-01

    A surface plasmon enhanced ellipsometry (SPEE) biosensor scheme based on the use of a photoelastic modulator (PEM) is reported. We show that the polarization parameters of a laser beam, tan , cos and ellipse orientation angle , can be directly measured by detecting the modulation signals at the f......A surface plasmon enhanced ellipsometry (SPEE) biosensor scheme based on the use of a photoelastic modulator (PEM) is reported. We show that the polarization parameters of a laser beam, tan , cos and ellipse orientation angle , can be directly measured by detecting the modulation signals...... at the first and second harmonics of the modulated frequency under a certain birefringence geometry. This leads to accurate measurement of refractive index variations within the evanescent field region close to the gold sensor surface, thereby enabling biosensing applications. Our experimental results confirm...

  15. Tianeptine: 5-HT uptake sites and 5-HT(1-7) receptors modulate memory formation in an autoshaping Pavlovian/instrumental task.

    Meneses, Alfredo

    2002-05-01

    Recent studies using invertebrate and mammal species have revealed that, endogenous serotonin (5-hydroxytryptamine, 5-HT) modulates cognitive processes, particularly learning and memory, though, at present, it is unclear the manner, where, and how long 5-HT systems are involved. Hence in this work, an attempt was made to study the effects of 5-HT endogenous on memory formation, using a 5-HT uptake facilitator (tianeptine) and, selective 5-HT(1-7) receptor antagonists to determine whether 5-HT uptake sites and which 5-HT receptors are involved, respectively. Results showed that post-training tianeptine injection enhanced memory consolidation in an autoshaping Pavlovian/instrumental learning task, which has been useful to detect changes on memory formation elicited by drugs or aging. On interaction experiments, ketanserin (5-HT(1D/2A/2C) antagonist) slightly enhanced tianeptine effects, while WAY 100635 (5-HT(1A) antagonist), SB-224289 (5-HT(1B) inverse agonist), SB-200646 (5-HT(2B/2C) antagonist), ondansetron (5-HT(3) antagonist), GR 127487 (5-HT(4) antagonist), Ro 04-6790 (5-HT(6) antagonist), DR 4004 (5-HT(7) antagonist), or fluoxetine (an inhibitor of 5-HT reuptake) blocked the facilitatory tianeptine effect. Notably, together tianeptine and Ro 04-6790 impaired learning consolidation. Moreover, 5-HT depletion completely reversed the tianeptine effect. Tianeptine also normalized an impaired memory elicited by scopolamine (an antimuscarinic) or dizocilpine (non-competitive glutamatergic antagonist), while partially reversed that induced by TFMPP (5-HT(1B/1D/2A-2C/7) agonist/antagonist). Finally, tianeptine-fluoxetine coadministration had no effect on learning consolidation; nevertheless, administration of an acetylcholinesterase inhibitor, phenserine, potentiated subeffective tianeptine or fluoxetine doses. Collectively, these data confirmed that endogenously 5-HT modulates, via uptake sites and 5-HT(1-7) receptors, memory consolidation, and are consistent with the

  16. Reward-dependent modulation of working memory is associated with negative symptoms in schizophrenia.

    Hager, Oliver M; Kirschner, Matthias; Bischof, Martin; Hartmann-Riemer, Matthias N; Kluge, Agne; Seifritz, Erich; Tobler, Philippe N; Kaiser, Stefan

    2015-10-01

    The negative symptoms of schizophrenia have been associated with altered neural activity during both reward processing and cognitive processing. Even though increasing evidence suggests a strong interaction between these two domains, it has not been studied in relation to negative symptoms. To elucidate neural mechanisms of the reward-cognition interaction, we applied a letter variant of the n-back working memory task and varied the financial incentives for performance. In the interaction contrast, we found a significantly activated cluster in the rostral anterior cingulate cortex (ACC), the middle frontal gyrus, and the bilateral superior frontal gyrus. The interaction did not differ significantly between the patient group and a healthy control group, suggesting that patients with schizophrenia are on average able to integrate reward information and utilize this information to maximize cognitive performance. However within the patient group, we found a significant inverse correlation of ACC activity with the factor diminished expression. This finding is consistent with the model that a lack of available cognitive resources leads to diminished expression. We therefore argue that patients with diminished expression have difficulties in recruiting additional cognitive resources (as implemented in the ACC) in response to an anticipated reward. Due to this lack of cognitive resources, less processing capacity is available for effective expression, resulting in diminished expressive behavior. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. Individual visual working memory capacities and related brain oscillatory activities are modulated by color preferences.

    Kawasaki, Masahiro; Yamaguchi, Yoko

    2012-01-01

    Subjective preferences affect many processes, including motivation, along with individual differences. Although incentive motivations are proposed to increase our limited visual working memory (VWM) capacity, much less is known about the effects of subjective preferences on VWM-related brain systems, such as the prefrontal and parietal cortices. Here, we investigate the differences in VWM capacities and brain activities during presentation of preferred and non-preferred colors. To this end, we used time-frequency (TF) analyses of electroencephalograph (EEG) data recorded during a delayed-response task. Behavioral results showed that the individual VWM capacities of preferred colors were significantly higher than those of non-preferred colors. The EEG results showed that the frontal theta and beta amplitudes for maintenance of preferred colors were higher than those of non-preferred colors. Interestingly, the frontal beta amplitudes were consistent with recent EEG recordings of the effects of reward on VWM systems, in that they were strongly and individually correlated with increasing VWM capacities from non-preferred to preferred colors. These results suggest that subjective preferences affect VWM systems in a similar manner to reward-incentive motivations.

  18. Postnatal Vitamin D Intake Modulates Hippocampal Learning and Memory in Adult Mice.

    Liang, Qiujuan; Cai, Chunhui; Duan, Dongxia; Hu, Xinyu; Hua, Wanhao; Jiang, Peicheng; Zhang, Liu; Xu, Jun; Gao, Zhengliang

    2018-01-01

    Vitamin D (VD) is a neuroactive steroid crucial for brain development, function and homeostasis. Its deficiency is associated with numerous brain conditions. As such, VD and its variants are routinely taken by a broad of groups with/without known VD deficiency. In contrast, the harmful effects of VD overdose have been poorly studied. Similarly, the developmental stage-specific VD deficiency and overdose have been rarely explored. In the present work, we showed that postnatal VD supplementation enhanced the motor function transiently in the young adult, but not in the older one. Postnatal VD intake abnormality did not impact the anxiety and depressive behavior but was detrimental to spatial learning and hippocampus-dependent memory. At the molecular level we failed to observe an obvious and constant change with the neural development and activity-related genes examined. However, disrupted developmental expression dynamics were observed for most of the genes, suggesting that the altered neural development dynamics and therefore aberrant adult plasticity might underlie the functional deficits. Our work highlights the essence of VD homeostasis in neural development and adult brain function. Further studies are needed to determine the short- and long-term effects VD intake status may have on brain development, homeostasis, and diseases.

  19. Working memory load modulates the neural response to other's pain: Evidence from an ERP study.

    Cui, Fang; Zhu, Xiangru; Luo, Yuejia; Cheng, Jiaping

    2017-03-22

    The present study investigated the time course of processing other's pain under different conditions of working memory (WM) load. Event-related potentials (ERPs) were recorded while the participants held two digits (low WM load) or six digits (high WM load) in WM and viewed pictures that showed others who were in painful or non-painful situations. Robust WM-load×Picture interactions were found for the N2 and LPP components. In the high WM-load condition, painful pictures elicited significantly larger amplitudes than non-painful pictures. In the low WM load condition, the difference between the painful and non-painful pictures was not significant. These ERP results indicate that WM load can influence both the early automatic N2 component and late cognitive LPP component. Compared with high WM load, low WM load reduced affective arousal and emotional sharing in response to other's pain and weakened the cognitive evaluation of task irrelevant stimuli. These findings are explained from the load theory perspective. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. From specificity to sensitivity: affective states modulate visual working memory for emotional expressive faces.

    Maran, Thomas; Sachse, Pierre; Furtner, Marco

    2015-01-01

    Previous findings suggest that visual working memory (VWM) preferentially remembers angry looking faces. However, the meaning of facial actions is construed in relation to context. To date, there are no studies investigating the role of perceiver-based context when processing emotional cues in VWM. To explore the influence of affective context on VWM for faces, we conducted two experiments using both a VWM task for emotionally expressive faces and a mood induction procedure. Affective context was manipulated by unpleasant (Experiment 1) and pleasant (Experiment 2) IAPS pictures in order to induce an affect high in motivational intensity (defensive or appetitive, respectively) compared to a low arousal control condition. Results indicated specifically increased sensitivity of VWM for angry looking faces in the neutral condition. Enhanced VWM for angry faces was prevented by inducing affects of high motivational intensity. In both experiments, affective states led to a switch from specific enhancement of angry expressions in VWM to an equally sensitive representation of all emotional expressions. Our findings demonstrate that emotional expressions are of different behavioral relevance for the receiver depending on the affective context, supporting a functional organization of VWM along with flexible resource allocation. In VWM, stimulus processing adjusts to situational requirements and transitions from a specifically prioritizing default mode in predictable environments to a sensitive, hypervigilant mode in exposure to emotional events.

  1. Individual language experience modulates rapid formation of cortical memory circuits for novel words

    Kimppa, Lilli; Kujala, Teija; Shtyrov, Yury

    2016-01-01

    Mastering multiple languages is an increasingly important ability in the modern world; furthermore, multilingualism may affect human learning abilities. Here, we test how the brain’s capacity to rapidly form new representations for spoken words is affected by prior individual experience in non-native language acquisition. Formation of new word memory traces is reflected in a neurophysiological response increase during a short exposure to novel lexicon. Therefore, we recorded changes in electrophysiological responses to phonologically native and non-native novel word-forms during a perceptual learning session, in which novel stimuli were repetitively presented to healthy adults in either ignore or attend conditions. We found that larger number of previously acquired languages and earlier average age of acquisition (AoA) predicted greater response increase to novel non-native word-forms. This suggests that early and extensive language experience is associated with greater neural flexibility for acquiring novel words with unfamiliar phonology. Conversely, later AoA was associated with a stronger response increase for phonologically native novel word-forms, indicating better tuning of neural linguistic circuits to native phonology. The results suggest that individual language experience has a strong effect on the neural mechanisms of word learning, and that it interacts with the phonological familiarity of the novel lexicon. PMID:27444206

  2. Postnatal Vitamin D Intake Modulates Hippocampal Learning and Memory in Adult Mice

    Qiujuan Liang

    2018-04-01

    Full Text Available Vitamin D (VD is a neuroactive steroid crucial for brain development, function and homeostasis. Its deficiency is associated with numerous brain conditions. As such, VD and its variants are routinely taken by a broad of groups with/without known VD deficiency. In contrast, the harmful effects of VD overdose have been poorly studied. Similarly, the developmental stage-specific VD deficiency and overdose have been rarely explored. In the present work, we showed that postnatal VD supplementation enhanced the motor function transiently in the young adult, but not in the older one. Postnatal VD intake abnormality did not impact the anxiety and depressive behavior but was detrimental to spatial learning and hippocampus-dependent memory. At the molecular level we failed to observe an obvious and constant change with the neural development and activity-related genes examined. However, disrupted developmental expression dynamics were observed for most of the genes, suggesting that the altered neural development dynamics and therefore aberrant adult plasticity might underlie the functional deficits. Our work highlights the essence of VD homeostasis in neural development and adult brain function. Further studies are needed to determine the short- and long-term effects VD intake status may have on brain development, homeostasis, and diseases.

  3. Individual visual working memory capacities and related brain oscillatory activities are modulated by color preferences

    Masahiro eKawasaki

    2012-11-01

    Full Text Available Subjective preferences affect many processes, including motivation, along with individual differences. Although incentive motivations are proposed to increase our limited visual working memory (VWM capacity, much less is known about the effects of subjective preferences on VWM-related brain systems, such as the prefrontal and parietal cortices. Here, we investigate the differences in VWM capacities and brain activities during presentation of preferred and non-preferred colors. To this end, we used time-frequency analyses of electroencephalograph (EEG data recorded during a delayed-response task. Behavioral results showed that the individual VWM capacities of preferred colors were significantly higher than those of non-preferred colors. The EEG results showed that the frontal theta and beta amplitudes for maintenance of preferred colors were higher than those of non-preferred colors. Interestingly, the frontal beta amplitudes were consistent with recent EEG recordings of the effects of reward on VWM systems, in that they were strongly and individually correlated with increasing VWM capacities from non-preferred to preferred colors. These results suggest that subjective preferences affect VWM systems in a similar manner to reward-incentive motivations.

  4. Wind effect on PV module temperature: Analysis of different techniques for an accurate estimation.

    Schwingshackl, Clemens; Petitta, Marcello; Ernst Wagner, Jochen; Belluardo, Giorgio; Moser, David; Castelli, Mariapina; Zebisch, Marc; Tetzlaff, Anke

    2013-04-01

    In this abstract a study on the influence of wind to model the PV module temperature is presented. This study is carried out in the framework of the PV-Alps INTERREG project in which the potential of different photovoltaic technologies is analysed for alpine regions. The PV module temperature depends on different parameters, such as ambient temperature, irradiance, wind speed and PV technology [1]. In most models, a very simple approach is used, where the PV module temperature is calculated from NOCT (nominal operating cell temperature), ambient temperature and irradiance alone [2]. In this study the influence of wind speed on the PV module temperature was investigated. First, different approaches suggested by various authors were tested [1], [2], [3], [4], [5]. For our analysis, temperature, irradiance and wind data from a PV test facility at the airport Bolzano (South Tyrol, Italy) from the EURAC Institute of Renewable Energies were used. The PV module temperature was calculated with different models and compared to the measured PV module temperature at the single panels. The best results were achieved with the approach suggested by Skoplaki et al. [1]. Preliminary results indicate that for all PV technologies which were tested (monocrystalline, amorphous, microcrystalline and polycrystalline silicon and cadmium telluride), modelled and measured PV module temperatures show a higher agreement (RMSE about 3-4 K) compared to standard approaches in which wind is not considered. For further investigation the in-situ measured wind velocities were replaced with wind data from numerical weather forecast models (ECMWF, reanalysis fields). Our results show that the PV module temperature calculated with wind data from ECMWF is still in very good agreement with the measured one (R² > 0.9 for all technologies). Compared to the previous analysis, we find comparable mean values and an increasing standard deviation. These results open a promising approach for PV module

  5. A Randomized Controlled Trial of the Group-Based Modified Story Memory Technique in TBI

    2017-10-01

    major task was to coordinate the study staff for the clinical trial. This is also a time- consuming processing that involves hiring the appropriate...for improving NLM in individuals with Multiple Sclerosis (MS) and TBI across three realms of functioning, objective behavior , brain functioning and...improving new learning and memory in individuals with Multiple Sclerosis (MS) and TBI across three realms of functioning, objective behavior , brain

  6. Techniques to reduce memory requirements for coupled photon-electron transport

    Turcksin, Bruno; Ragusa, Jean; Morel, Jim

    2011-01-01

    In this work, we present two methods to decrease memory needs while solving the photon- electron transport equation. The coupled transport of electrons and photons is of importance in radiotherapy because it describes the interactions of X-rays with matter. One of the issues of discretized electron transport is that the electron scattering is highly forward peaked. A common approximation is to represent the peak in the scattering cross section by a Dirac distribution. This is convenient, but the integration over all angles of this distribution requires the use of Galerkin quadratures. By construction these quadratures impose that the number of flux moments be equal to the number of directions (number of angular fluxes), which is very demanding in terms of memory. In this study, we show that even if the number of moments is not as large as the number of directions, an accurate solution can be obtained when using Galerkin quadratures. Another method to decrease the memory needs involves choosing an appropriate reordering of the energy groups. We show in this paper that an appropriate alternation of photons/electrons groups allows to rewrite one transport problem of n groups as gcd successive transport problems of n/gcd groups where gcd is the greatest common divisor between the number of photon groups and the number of electron groups. (author)

  7. Negative emotion modulates prefrontal cortex activity during a working memory task: A NIRS study

    Sachiyo eOzawa

    2014-02-01

    Full Text Available This study investigated the neural processing underlying the cognitive control of emotions induced by the presentation of task-irrelevant emotional pictures before a working memory task. Previous studies have suggested that the cognitive control of emotion involves the prefrontal regions. Therefore, we measured the hemodynamic responses that occurred in the prefrontal region with a 16-channel near-infrared spectroscopy (NIRS system. In our experiment, participants observed two negative or two neutral pictures in succession immediately before a 1-back or 3-back task. Pictures were selected from the International Affective Picture System. We measured the changes in the concentration of oxygenated hemoglobin (oxyHb during picture presentation and during the n-back task. The emotional valence of the picture affected the oxyHb changes in anterior parts of the medial prefrontal cortex (located in the left and right superior frontal gyrus and left inferior frontal gyrus during the n-back task; the oxyHb changes during the task were significantly greater following negative rather than neutral stimulation. As indicated in a number of previous studies, and the time courses of the oxyHb changes in our study, activation in these locations is possibly led by cognitive control of emotion, though we cannot deny it may simply be emotional responses. There were no effects of emotion on oxyHb changes during picture presentation or on n-back task performance. Although further studies are necessary to confirm this interpretation, our findings suggest that NIRS can be used to investigate neural processing during emotional control.

  8. Input from the medial geniculate nucleus modulates amygdala encoding of fear memory discrimination.

    Ferrara, Nicole C; Cullen, Patrick K; Pullins, Shane P; Rotondo, Elena K; Helmstetter, Fred J

    2017-09-01

    Generalization of fear can involve abnormal responding to cues that signal safety and is common in people diagnosed with post-traumatic stress disorder. Differential auditory fear conditioning can be used as a tool to measure changes in fear discrimination and generalization. Most prior work in this area has focused on elevated amygdala activity as a critical component underlying generalization. The amygdala receives input from auditory cortex as well as the medial geniculate nucleus (MgN) of the thalamus, and these synapses undergo plastic changes in response to fear conditioning and are major contributors to the formation of memory related to both safe and threatening cues. The requirement for MgN protein synthesis during auditory discrimination and generalization, as well as the role of MgN plasticity in amygdala encoding of discrimination or generalization, have not been directly tested. GluR1 and GluR2 containing AMPA receptors are found at synapses throughout the amygdala and their expression is persistently up-regulated after learning. Some of these receptors are postsynaptic to terminals from MgN neurons. We found that protein synthesis-dependent plasticity in MgN is necessary for elevated freezing to both aversive and safe auditory cues, and that this is accompanied by changes in the expressions of AMPA receptor and synaptic scaffolding proteins (e.g., SHANK) at amygdala synapses. This work contributes to understanding the neural mechanisms underlying increased fear to safety signals after stress. © 2017 Ferrara et al.; Published by Cold Spring Harbor Laboratory Press.

  9. The endocannabinoid transport inhibitor AM404 differentially modulates recognition memory in rats depending on environmental aversiveness

    Patrizia eCampolongo

    2012-03-01

    Full Text Available Cannabinoid compounds may influence both emotional and cognitive processes depending on the level of environmental aversiveness at the time of drug administration. However, the mechanisms responsible for these responses remain to be elucidated. The present experiments investigated the effects induced by the endocannabinoid transport inhibitor AM404 (0.5-5 mg/kg, i.p. on bothemotional and cognitive performances of rats tested in a Spatial Open Field task and subjected to different experimental settings, named High Arousal and Low Arousal conditions. The two different experimental conditions influenced emotional reactivity independently of drug administration. Indeed, vehicle-treated rats exposed to the Low Arousal condition spent more time in the centre of the arena than vehicle-treated rats exposed to the High Arousal context. Conversely, the different arousal conditions did not affect the cognitive performances of vehicle-treated animals such as the capability to discriminate a spatial displacement of the objects or an object substitution.AM404 administration did not alter the locomotor activity of the animals exposed to both environmental conditions. Interestingly, AM404 administration increased the emotional reactivity of rats exposed to the High Arousal condition but did not influence emotionality of rats exposed to the Low Arousal condition. Moreover, AM404 administration influenced the cognitive parameters depending on the level of emotional arousal: it impaired the capability of rats exposed to the High Arousal condition to recognize a novel object while it did not induce any impairing effect in rats exposed to the Low Arousal condition.These findings suggest that drugs which enhance the endocannabinoid signalling induce different effects on recognition memory performance depending on the level of emotional arousal induced by the environmental conditions.

  10. Amphetamine modulates brain signal variability and working memory in younger and older adults.

    Garrett, Douglas D; Nagel, Irene E; Preuschhof, Claudia; Burzynska, Agnieszka Z; Marchner, Janina; Wiegert, Steffen; Jungehülsing, Gerhard J; Nyberg, Lars; Villringer, Arno; Li, Shu-Chen; Heekeren, Hauke R; Bäckman, Lars; Lindenberger, Ulman

    2015-06-16

    Better-performing younger adults typically express greater brain signal variability relative to older, poorer performers. Mechanisms for age and performance-graded differences in brain dynamics have, however, not yet been uncovered. Given the age-related decline of the dopamine (DA) system in normal cognitive aging, DA neuromodulation is one plausible mechanism. Hence, agents that boost systemic DA [such as d-amphetamine (AMPH)] may help to restore deficient signal variability levels. Furthermore, despite the standard practice of counterbalancing drug session order (AMPH first vs. placebo first), it remains understudied how AMPH may interact with practice effects, possibly influencing whether DA up-regulation is functional. We examined the effects of AMPH on functional-MRI-based blood oxygen level-dependent (BOLD) signal variability (SD(BOLD)) in younger and older adults during a working memory task (letter n-back). Older adults expressed lower brain signal variability at placebo, but met or exceeded young adult SD(BOLD) levels in the presence of AMPH. Drug session order greatly moderated change-change relations between AMPH-driven SD(BOLD) and reaction time means (RT(mean)) and SDs (RT(SD)). Older adults who received AMPH in the first session tended to improve in RT(mean) and RT(SD) when SD(BOLD) was boosted on AMPH, whereas younger and older adults who received AMPH in the second session showed either a performance improvement when SD(BOLD) decreased (for RT(mean)) or no effect at all (for RT(SD)). The present findings support the hypothesis that age differences in brain signal variability reflect aging-induced changes in dopaminergic neuromodulation. The observed interactions among AMPH, age, and session order highlight the state- and practice-dependent neurochemical basis of human brain dynamics.

  11. Sucrose-induced analgesia during early life modulates adulthood learning and memory formation.

    Nuseir, Khawla Q; Alzoubi, Karem H; Alabwaini, Jehad; Khabour, Omar F; Kassab, Manal I

    2015-06-01

    This study is aimed at examining the long-term effects of chronic pain during early life (postnatal day 0 to 8weeks), and intervention using sucrose, on cognitive functions during adulthood in rats. Pain was induced in rat pups via needle pricks of the paws. Sucrose solution or paracetamol was administered for analgesia before the paw prick. Control groups include tactile stimulation to account for handling and touching the paws, and sucrose alone was used. All treatments were started on day one of birth and continued for 8weeks. At the end of the treatments, behavioral studies were conducted to test the spatial learning and memory using radial arm water maze (RAWM), as well as pain threshold via foot-withdrawal response to a hot plate apparatus. Additionally, the hippocampus was dissected, and blood was collected. Levels of neurotrophins (BDNF, IGF-1 and NT-3) and endorphins were assessed using ELISA. The results show that chronic noxious stimulation resulted in comparable foot-withdrawal latency between noxious and tactile groups. On the other hand, pretreatment with sucrose or paracetamol increased pain threshold significantly both in naive rats and noxiously stimulated rats (Pmemory, and sucrose treatment prevented such impairment (Pmemory impairment, and pretreatment with sucrose prevented this impairment via mechanisms that seem to involve BDNF. As evident in the results, sucrose, whether alone or in the presence of pre-noxious stimulation, increases pain threshold in such circumstances; most likely via a mechanism that involves an increase in endogenous opioids. Copyright © 2015 Elsevier Inc. All rights reserved.

  12. Early auditory evoked potential is modulated by selective attention and related to individual differences in visual working memory capacity.

    Giuliano, Ryan J; Karns, Christina M; Neville, Helen J; Hillyard, Steven A

    2014-12-01

    A growing body of research suggests that the predictive power of working memory (WM) capacity for measures of intellectual aptitude is due to the ability to control attention and select relevant information. Crucially, attentional mechanisms implicated in controlling access to WM are assumed to be domain-general, yet reports of enhanced attentional abilities in individuals with larger WM capacities are primarily within the visual domain. Here, we directly test the link between WM capacity and early attentional gating across sensory domains, hypothesizing that measures of visual WM capacity should predict an individual's capacity to allocate auditory selective attention. To address this question, auditory ERPs were recorded in a linguistic dichotic listening task, and individual differences in ERP modulations by attention were correlated with estimates of WM capacity obtained in a separate visual change detection task. Auditory selective attention enhanced ERP amplitudes at an early latency (ca. 70-90 msec), with larger P1 components elicited by linguistic probes embedded in an attended narrative. Moreover, this effect was associated with greater individual estimates of visual WM capacity. These findings support the view that domain-general attentional control mechanisms underlie the wide variation of WM capacity across individuals.

  13. Early Auditory Evoked Potential Is Modulated by Selective Attention and Related to Individual Differences in Visual Working Memory Capacity

    Giuliano, Ryan J.; Karns, Christina M.; Neville, Helen J.; Hillyard, Steven A.

    2015-01-01

    A growing body of research suggests that the predictive power of working memory (WM) capacity for measures of intellectual aptitude is due to the ability to control attention and select relevant information. Crucially, attentional mechanisms implicated in controlling access to WM are assumed to be domain-general, yet reports of enhanced attentional abilities in individuals with larger WM capacities are primarily within the visual domain. Here, we directly test the link between WM capacity and early attentional gating across sensory domains, hypothesizing that measures of visual WM capacity should predict an individual’s capacity to allocate auditory selective attention. To address this question, auditory ERPs were recorded in a linguistic dichotic listening task, and individual differences in ERP modulations by attention were correlated with estimates of WM capacity obtained in a separate visual change detection task. Auditory selective attention enhanced ERP amplitudes at an early latency (ca. 70–90 msec), with larger P1 components elicited by linguistic probes embedded in an attended narrative. Moreover, this effect was associated with greater individual estimates of visual WM capacity. These findings support the view that domain-general attentional control mechanisms underlie the wide variation of WM capacity across individuals. PMID:25000526

  14. Observation of a continuous modulation in a shape-memory alloy

    Lashley, Jason C [Los Alamos National Laboratory; Smith, James L [Los Alamos National Laboratory; Mihaila, Bogdan [Los Alamos National Laboratory; Riseborough, P [TEMPLE UNIV; Ratcliffe, W [NIST; Alatas, A [ANL; Manley, M E [LLNL; Shapiro, S M [BROOKHAVEN NATIONAL LAB; Opeil, C P [BOSTON COLLEGE; Wynn, B [ORNL

    2008-01-01

    Elastic neutron-scattering, inelastic x-ray scattering, specific-heat, and pressure-dependent electrical transport measurements have been made on single crystals of AuZn and Au{sub 0.52}Zn{sub 0.48}. Elastic neutron scattering detects new commensurate Bragg peaks (modulation) appearing at Q = (1.33,0.67,0) at temperatures corresponding to each sample's transition temperature (T{sub M} = 64 and 45 K, respectively). Although the new Bragg peaks appear in a discontinuous manner in the Au{sub 0.52}Zn{sub 0.48} sample, they appear in a continuous manner in AuZn. Surprising us, the temperature dependence of the AuZn Bragg peak intensity and the specific-heat jump near T{sub M} are in favorable accord with a continuous transition. A fit to the pressure dependence of T{sub M} suggests the presence of a critical end point in the AuZn phase diagram located at T*{sub M} = 2.7 K and p* = 3.1 GPa.

  15. The neural correlates of competition during memory retrieval are modulated by attention to the cues.

    Danker, Jared F; Fincham, Jon M; Anderson, John R

    2011-07-01

    As people learn more facts about a concept, those facts become more difficult to remember. This is called the fan effect, where fan refers to the number of facts known about a concept. Increasing fan has been shown to decrease accuracy and increase response time and left ventrolateral prefrontal cortex (VLPFC) activity during retrieval. In this study, participants learned 36 arbitrary person-location pairings and made recognition decisions while we recorded brain activity using fMRI. We separately manipulated the fan of each person and location, as well as the training procedure with which each pair was studied. In the person focus condition, participants studied pairs with a picture of the person's face and used the person as a retrieval cue during training. In the location focus condition, participants studied pairs with a picture of the location and used the location as a retrieval cue during training. We found that the fan of the focused cue had a greater effect on response time, accuracy, and left VLPFC activity during retrieval than the fan of the unfocused cue. We also found that the parahippocampal place area (PPA) was more active during the recognition of pairs studied in the location focus condition, but not when the fan of the location was high. Overall, we found opposite effects of fan on VLPFC and PPA that were modulated by cue focus. Copyright © 2011 Elsevier Ltd. All rights reserved.

  16. Investigation of the stationary state of parametric spin waves in antiferromagnetics by the modulation technique

    Andrienko, A.V.; Safonov, V.L.; Yakubovskij, A.Yu.

    1987-01-01

    The response of parametric electron and nuclear spin waves to weak modulation of a stationary magnetic field is investigated in the antiferromagnetics MnCO 3 and CsMnF 3 . The modulation response is calculated by taking into accout the phase mechanism of restriction of the parametric wave amplitude and positive nonlinear attenuation of the waves. Some characteristics of the stationary state of parametric electron and nuclear magnons are determined within the framework of the model by analysis of the experimental results: the nonlinear magnon interaction coefficient S k and the parameter κ which characterizes the relative contribution from positive nonlinear attenuation and the phase mechanism to the restriction of the number of parametric magnons. An anomaly in the behavior of the modulation response of the parametric nuclear magnons is observed in CsMnF 3 ; this is manifest in asubstantial decrease of the modulation response in a narrow supercriticality and modulation frequency range. A giant hexagonal anisotropy of the modulation response and nonlinear dynamic susceptibility of the nuclear magnons is observed in the same crystal. This may indicate a nonisotropic distribution of the magnons in k-space

  17. Module Testing Techniques for Nuclear Safety Critical Software Using LDRA Testing Tool

    Moon, Kwon-Ki; Kim, Do-Yeon; Chang, Hoon-Seon; Chang, Young-Woo; Yun, Jae-Hee; Park, Jee-Duck; Kim, Jae-Hack

    2006-01-01

    The safety critical software in the I and C systems of nuclear power plants requires high functional integrity and reliability. To achieve those requirement goals, the safety critical software should be verified and tested according to related codes and standards through verification and validation (V and V) activities. The safety critical software testing is performed at various stages during the development of the software, and is generally classified as three major activities: module testing, system integration testing, and system validation testing. Module testing involves the evaluation of module level functions of hardware and software. System integration testing investigates the characteristics of a collection of modules and aims at establishing their correct interactions. System validation testing demonstrates that the complete system satisfies its functional requirements. In order to generate reliable software and reduce high maintenance cost, it is important that software testing is carried out at module level. Module testing for the nuclear safety critical software has rarely been performed by formal and proven testing tools because of its various constraints. LDRA testing tool is a widely used and proven tool set that provides powerful source code testing and analysis facilities for the V and V of general purpose software and safety critical software. Use of the tool set is indispensable where software is required to be reliable and as error-free as possible, and its use brings in substantial time and cost savings, and efficiency

  18. Selective post-training time window for memory consolidation interference of cannabidiol into the prefrontal cortex: Reduced dopaminergic modulation and immediate gene expression in limbic circuits.

    Rossignoli, Matheus Teixeira; Lopes-Aguiar, Cleiton; Ruggiero, Rafael Naime; Do Val da Silva, Raquel Araujo; Bueno-Junior, Lezio Soares; Kandratavicius, Ludmyla; Peixoto-Santos, José Eduardo; Crippa, José Alexandre; Cecilio Hallak, Jaime Eduardo; Zuardi, Antonio Waldo; Szawka, Raphael Escorsim; Anselmo-Franci, Janete; Leite, João Pereira; Romcy-Pereira, Rodrigo Neves

    2017-05-14

    The prefrontal cortex (PFC), amygdala and hippocampus display a coordinated activity during acquisition of associative fear memories. Evidence indicates that PFC engagement in aversive memory formation does not progress linearly as previously thought. Instead, it seems to be recruited at specific time windows after memory acquisition, which has implications for the treatment of post-traumatic stress disorders. Cannabidiol (CBD), the major non-psychotomimetic phytocannabinoid of the Cannabis sativa plant, is known to modulate contextual fear memory acquisition in rodents. However, it is still not clear how CBD interferes with PFC-dependent processes during post-training memory consolidation. Here, we tested whether intra-PFC infusions of CBD immediately after or 5h following contextual fear conditioning was able to interfere with memory consolidation. Neurochemical and cellular correlates of the CBD treatment were evaluated by the quantification of extracellular levels of dopamine (DA), serotonin, and their metabolites in the PFC and by measuring the cellular expression of activity-dependent transcription factors in cortical and limbic regions. Our results indicate that bilateral intra-PFC CBD infusion impaired contextual fear memory consolidation when applied 5h after conditioning, but had no effect when applied immediately after it. This effect was associated with a reduction in DA turnover in the PFC following retrieval 5days after training. We also observed that post-conditioning infusion of CBD reduced c-fos and zif-268 protein expression in the hippocampus, PFC, and thalamus. Our findings support that CBD interferes with contextual fear memory consolidation by reducing PFC influence on cortico-limbic circuits. Copyright © 2017 IBRO. Published by Elsevier Ltd. All rights reserved.

  19. Interaction between harmane, a class of β-carboline alkaloids, and the CA1 serotonergic system in modulation of memory acquisition.

    Nasehi, Mohammad; Ghadimi, Fatemeh; Khakpai, Fatemeh; Zarrindast, Mohammad-Reza

    2017-09-01

    This study set to assess the involvement of dorsal hippocampus (CA1) serotonergic system on harmane induced memory acquisition deficit. We used one trial step-down inhibitory avoidancetask to evaluate memory retention and then, open field test to evaluate locomotor activity in adult male NMRI mice. The results showed that pre-training intra-peritoneal (i.p.) administration of harmane (12mg/kg) induced impairment of memory acquisition. Pre-training intra-CA1 administration of 5-HT1B/1D receptor agonist (CP94253; 0.5 and 5ng/mouse) and 5-HT2A/2B/2C receptor agonist (α-methyl 5-HT; 50ng/mouse) impaired memory acquisition. Furthermore, intra-CA1 administration of 5-HT1B/1D receptor antagonist (GR127935; 0.5ng/mouse) and 5-HT2 receptor antagonist (cinancerine; 5ng/mouse) improved memory acquisition. In addition, pre-training intra-CA1 injection of sub-threshold dose of CP94253 (0.05ng/mouse) and α-methyl 5-HT (5ng/mouse) potentiated impairment of memory acquisition induced by harmane (12mg/kg, i.p.). On the other hand, pre-training intra-CA1 infusion of sub-threshold dose of GR127935 (0.05ng/mouse) and cinancerine (0.5ng/mouse) with the administration of harmane (12mg/kg, i.p.) weakened impairment of memory acquisition. Moreover, all above doses of drugs did not change locomotor activity. The present findings suggest that there is an interaction between harmane and the CA1 serotonergic system in modulation of memory acquisition. Copyright © 2017 Elsevier Ireland Ltd and Japan Neuroscience Society. All rights reserved.

  20. Dosimetric feasibility of an “off-target isocenter” technique for cranial intensity-modulated radiosurgery

    Calvo-Ortega, Juan Francisco; Moragues, Sandra; Pozo, Miquel; Delgado, David; Casals, Joan

    2015-01-01

    To evaluate the dosimetric effect of placing the isocenter away from the planning target volume (PTV) on intensity-modulated radiosurgery (IMRS) plans to treat brain lesions. A total of 15 patients who received cranial IMRS at our institution were randomly selected. Each patient was treated with an IMRS plan designed with the isocenter located at the target center (plan A). A second off-target isocenter plan (plan B) was generated for each case. In all the plans,100% of the prescription dose covered 99% of the target volume. The plans A and B were compared for the target dosage (conformity index [CI] and homogeneity index) and organs-at-risk (OAR) dose sparing. Peripheral dose falloff was compared by using the metrics volume of normal brain receiving more than 12-Gy dose (V12) and CI at the level of the 50% of the prescription dose (CI 50%). The values found for each metric (plan B vs plan A) were (mean ± standard deviation [SD]) as follows—CI: 1.28 ± 0.15 vs 1.28 ± 0.15, p = 0.978; homogeneity index (HI): 1.29 ± 0.14 vs 1.34 ± 0.17, p = 0.079; maximum dose to the brainstem: 2.95 ± 2.11 vs 2.89 ± 1.88 Gy, p = 0.813; maximum dose to the optical pathway: 2.65 ± 4.18 vs 2.44 ± 4.03 Gy, p = 0.195; and maximum dose to the eye lens: 0.33 ± 0.73 vs 0.33 ± 0.53 Gy, p = 0.970. The values of the peripheral dose falloff were (plan B vs plan A) as follows—V12: 5.98 ± 4.95 vs 6.06 ± 4.92 cm"3, p = 0.622, and CI 50%: 6.08 ± 2.77 vs 6.28 ± 3.01, p = 0.119. The off-target isocenter solution resulted in dosimetrically comparable plans as the center-target isocenter technique, by avoiding the risk of gantry-couch collision during the cone beam computed tomography (CBCT) acquisition.

  1. Impact of Volumetric Modulated Arc Therapy Technique on Treatment With Partial Breast Irradiation

    Qiu Jianjian; Chang Zheng; Wu, Q. Jackie; Yoo, Sua; Horton, Janet; Yin Fangfang

    2010-01-01

    Purpose: To investigate the technical feasibility of volumetric modulated arc therapy (V-MAT) in the delivery of partial breast irradiation (PBI). Methods and Materials: V-MAT and the standard, three-dimensional conformal radiotherapy (3D-CRT), were compared retrospectively in 8 patients previously treated with PBI. These patients' plans were replanned with a single partial arc using V-MAT that included partial blocking to minimize normal tissue dose. Dosimetric parameters were calculated to evaluate plan quality. Quality assurance studies included verifying both the point and the multiple planar doses. Total monitor units and delivery time were also evaluated, and collision clearance was analyzed. Results: Volumes of ipsilateral lung irradiated to 10 Gy (V10) and 20 Gy (V20) by V-MAT were significantly less than those of 3D-CRT (p = 0.03 for V10 and p = 0.025 for V20). The volume of ipsilateral breast irradiated to 5 Gy was significantly less by using V-MAT than with 3D-CRT (p = 0.02), with a ratio of integrated dose of <1.00. The total mean monitor units (489 ± 38) for V-MAT were significantly less than those for 3D-CRT (634 ± 123) (p = 0.017), with a 23% reduction. The average machine delivery time was 1.21 ± 0.10 min for the V-MAT plans and 6.28 ± 1.40 min for the 3D-CRT plans, resulting in a reduction factor of 80.1%. The conformity indexes were 1.3 in the V-MAT plans and 1.5 in the 3D-CRT plans (p = 0.102). Conclusions: V-MAT technology is feasible for PBI patients. Compared to a conventional 3D-CRT technique, it is more efficient, offers equivalent or better dose conformity, delivers lower doses to the ipsilateral lung and breast, and may potentially reduce intrafractional motion.

  2. Phenolic acid intake, delivered via moderate champagne wine consumption, improves spatial working memory via the modulation of hippocampal and cortical protein expression/activation.

    Corona, Giulia; Vauzour, David; Hercelin, Justine; Williams, Claire M; Spencer, Jeremy P E

    2013-11-10

    While much data exist for the effects of flavonoid-rich foods on spatial memory in rodents, there are no such data for foods/beverages predominantly containing hydroxycinnamates and phenolic acids. To address this, we investigated the effects of moderate Champagne wine intake, which is rich in these components, on spatial memory and related mechanisms relative to the alcohol- and energy-matched controls. In contrast to the isocaloric and alcohol-matched controls, supplementation with Champagne wine (1.78 ml/kg BW, alcohol 12.5% vol.) for 6 weeks led to an improvement in spatial working memory in aged rodents. Targeted protein arrays indicated that these behavioral effects were paralleled by the differential expression of a number of hippocampal and cortical proteins (relative to the isocaloric control group), including those involved in signal transduction, neuroplasticity, apoptosis, and cell cycle regulation. Western immunoblotting confirmed the differential modulation of brain-derived neurotrophic factor, cAMP response-element-binding protein (CREB), p38, dystrophin, 2',3'-cyclic-nucleotide 3'-phosphodiesterase, mammalian target of rapamycin (mTOR), and Bcl-xL in response to Champagne supplementation compared to the control drink, and the modulation of mTOR, Bcl-xL, and CREB in response to alcohol supplementation. Our data suggest that smaller phenolics such as gallic acid, protocatechuic acid, tyrosol, caftaric acid, and caffeic acid, in addition to flavonoids, are capable of exerting improvements in spatial memory via the modulation in hippocampal signaling and protein expression. Changes in spatial working memory induced by the Champagne supplementation are linked to the effects of absorbed phenolics on cytoskeletal proteins, neurotrophin expression, and the effects of alcohol on the regulation of apoptotic events in the hippocampus and cortex.

  3. An implicit scheme with memory reduction technique for steady state solutions of DVBE in all flow regimes

    Yang, L. M.; Shu, C.; Yang, W. M.; Wu, J.

    2018-04-01

    High consumption of memory and computational effort is the major barrier to prevent the widespread use of the discrete velocity method (DVM) in the simulation of flows in all flow regimes. To overcome this drawback, an implicit DVM with a memory reduction technique for solving a steady discrete velocity Boltzmann equation (DVBE) is presented in this work. In the method, the distribution functions in the whole discrete velocity space do not need to be stored, and they are calculated from the macroscopic flow variables. As a result, its memory requirement is in the same order as the conventional Euler/Navier-Stokes solver. In the meantime, it is more efficient than the explicit DVM for the simulation of various flows. To make the method efficient for solving flow problems in all flow regimes, a prediction step is introduced to estimate the local equilibrium state of the DVBE. In the prediction step, the distribution function at the cell interface is calculated by the local solution of DVBE. For the flow simulation, when the cell size is less than the mean free path, the prediction step has almost no effect on the solution. However, when the cell size is much larger than the mean free path, the prediction step dominates the solution so as to provide reasonable results in such a flow regime. In addition, to further improve the computational efficiency of the developed scheme in the continuum flow regime, the implicit technique is also introduced into the prediction step. Numerical results showed that the proposed implicit scheme can provide reasonable results in all flow regimes and increase significantly the computational efficiency in the continuum flow regime as compared with the existing DVM solvers.

  4. Properties of a novel radiophotoluminescent readout system using a cw modulated UV laser diode and phase-sensitive technique

    Zhao, C.; Kurobori, T.; Miyamoto, Y.; Yamamoto, T.

    2011-01-01

    We have proposed and constructed a novel readout system for measuring a dose-dependent radiophotoluminescence (RPL) signal of a silver-activated phosphate glass dosimeter. The present reader consists of a modulated continuous-wave (cw) ultraviolet (UV) laser diode at 375 nm as an excitation and a phase-sensitive technique using a lock-in amplifier. Preliminary results using a home-made reader are compared with those of the conventional technique based on a combination of a pulsed UV N 2 laser excitation at 337 nm and a photon counting system.

  5. Both a Nicotinic Single Nucleotide Polymorphism (SNP) and a Noradrenergic SNP Modulate Working Memory Performance when Attention Is Manipulated

    Greenwood, Pamela M.; Sundararajan, Ramya; Lin, Ming-Kuan; Kumar, Reshma; Fryxell, Karl J.; Parasuraman, Raja

    2009-01-01

    We investigated the relation between the two systems of visuospatial attention and working memory by examining the effect of normal variation in cholinergic and noradrenergic genes on working memory performance under attentional manipulation. We previously reported that working memory for location was impaired following large location precues,…

  6. Design and Simulation of Control Technique for Permanent Magnet Synchronous Motor Using Space Vector Pulse Width Modulation

    Khan, Mansoor; Yong, Wang; Mustafa, Ehtasham

    2017-07-01

    After the rapid advancement in the field of power electronics devices and drives for last few decades, there are different kinds of Pulse Width Modulation techniques which have been brought to the market. The applications ranging from industrial appliances to military equipment including the home appliances. The vey common application for the PWM is three phase voltage source inverter, which is used to convert DC to AC in the homes to supply the power to the house in case electricity failure, usually named as Un-interrupted Power Supply. In this paper Space Vector Pulse Width Modulation techniques is discussed and analysed under the control technique named as Field Oriented Control. The working and implementation of this technique has been studied by implementing on the three phase bridge inverter. The technique is used to control the Permanente Magnet Synchronous Motor. The drive system is successfully implemented in MATLAB/Simulink using the mathematical equation and algorithm to achieve the satisfactory results. PI type of controller is used to tuned ers of the motothe parametr i.e. torque and current.

  7. Modulating influences of memory strength and sensitivity of the retrieval test on the detectability of the sleep consolidation effect.

    Schoch, Sarah F; Cordi, Maren J; Rasch, Björn

    2017-11-01

    Emotionality can increase recall probability of memories as emotional information is highly relevant for future adaptive behavior. It has been proposed that memory processes acting during sleep selectively promote the consolidation of emotional memories, so that neutral memories no longer profit from sleep consolidation after learning. This appears as a selective effect of sleep for emotional memories. However, other factors contribute to the appearance of a consolidation benefit and influence this interpretation. Here we show that the strength of the memory trace before sleep and the sensitivity of the retrieval test after sleep are critical factors contributing to the detection of the benefit of sleep on memory for emotional and neutral stimuli. 228 subjects learned emotional and neutral pictures and completed a free recall after a 12-h retention interval of either sleep or wakefulness. We manipulated memory strength by including an immediate retrieval test before the retention interval in half of the participants. In addition, we varied the sensitivity of the retrieval test by including an interference learning task before retrieval testing in half of the participants. We show that a "selective" benefit of sleep for emotional memories only occurs in the condition with high memory strength. Furthermore, this "selective" benefit disappeared when we controlled for the memory strength before the retention interval and used a highly sensitive retrieval test. Our results indicate that although sleep benefits are more robust for emotional memories, neutral memories similarly profit from sleep after learning when more sensitive indicators are used. We conclude that whether sleep benefits on memory appear depends on several factors, including emotion, memory strength and sensitivity of the retrieval test. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. "Digit anatomy": a new technique for learning anatomy using motor memory.

    Oh, Chang-Seok; Won, Hyung-Sun; Kim, Kyong-Jee; Jang, Dong-Su

    2011-01-01

    Gestural motions of the hands and fingers are powerful tools for expressing meanings and concepts, and the nervous system has the capacity to retain multiple long-term motor memories, especially including movements of the hands. We developed many sets of successive movements of both hands, referred to as "digit anatomy," and made students practice the movements which express (1) the aortic arch, subclavian, and thoracoacromial arteries and their branches, (2) the celiac trunk, superior mesenteric artery and their branches, and formation of the portal vein, (3) the heart and the coronary arteries, and (4) the brachial, lumbar, and sacral plexuses. A feedback survey showed that digit anatomy was helpful for the students not only in memorizing anatomical structures but also in understanding their functions. Out of 40 students, 34 of them who learned anatomy with the help of digit anatomy were "very satisfied" or "generally satisfied" with this new teaching method. Digit anatomy that was used to express the aortic arch, subclavian, and thoracoacromial arteries and their branches was more helpful than those representing other structures. Although the movements of digit anatomy are expected to be remembered longer than the exact meaning of each movement, invoking the motor memory of the movement may help to make relearning of the same information easier and faster in the future. Copyright © 2011 American Association of Anatomists.

  9. Prefrontal activity during working memory is modulated by the interaction of variation in CB1 and COX2 coding genes and correlates with frequency of cannabis use.

    Taurisano, Paolo; Antonucci, Linda A; Fazio, Leonardo; Rampino, Antonio; Romano, Raffaella; Porcelli, Annamaria; Masellis, Rita; Colizzi, Marco; Quarto, Tiziana; Torretta, Silvia; Di Giorgio, Annabella; Pergola, Giulio; Bertolino, Alessandro; Blasi, Giuseppe

    2016-08-01

    The CB1 cannabinoid receptor is targeted in the brain by endocannabinoids under physiological conditions as well as by delta9-tetrahydrocannabinol under cannabis use. Furthermore, its signaling appears to affect brain cognitive processing. Recent findings highlight a crucial role of cyclooxygenase-2 (COX-2) in the mechanism of intraneuronal CB1 signaling transduction, while others indicate that two single nucleotide polymorphisms (SNPs) (rs1406977 and rs20417) modulate expression of CB1 (CNR1) and COX-2 (PTGS2) coding genes, respectively. Here, our aim was to use fMRI to investigate in healthy humans whether these SNPs interact in modulating prefrontal activity during working memory processing and if this modulation is linked with cannabis use. We recruited 242 healthy subjects genotyped for CNR1 rs1406977 and PTGS2 rs20417 that performed the N-back working memory task during fMRI and were interviewed using the Cannabis Experience Questionnaire (CEQ). We found that the interaction between CNR1 rs1406977 and PTGS2 rs20417 is associated with dorsolateral prefrontal cortex (DLPFC) activity such that specific genotype configurations (CNR1 C carriers/PTGS2 C carriers and CNR1 TT/PTGS2 GG) predict lower cortical response versus others in spite of similar behavioral accuracy. Furthermore, DLPFC activity in the cluster associated with the CNR1 by PTGS2 interaction was negatively correlated with behavioral efficiency and positively correlated with frequency of cannabis use in cannabis users. These results suggest that a genetically modulated balancing of signaling within the CB1-COX-2 pathway may reflect on more or less efficient patterns of prefrontal activity during working memory. Frequency of cannabis use may be a factor for further modulation of CNR1/PTGS2-mediated cortical processing associated with this cognitive process. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. A novel amplitude modulated triangular carrier gain linearization technique for SPWM inverter

    Ramkumar Subburam

    2009-01-01

    Full Text Available This paper presents a new method to extend the linearity of the sinusoidal pulse width modulation (SPWM to full range of the pulse dropping region. The proposed amplitude modulated triangular carrier PWM method (AMTCPWM increases the dynamic range of the SPWM control and eliminates the need of nonlinear modulation in the pulse dropping region to reach the square wave boundary. The novel method combines the spectral quality of SPWM with the efficient single-mode linear control. A simple analytical characterization of the exact method is presented and its effectiveness is demonstrated using simulation for the basic single-phase H-bridge inverter circuit. The hardware results of the designed prototype inverter are presented to validate the betterment of the novel scheme. .

  11. Implications of the Declarative/Procedural Model for Improving Second Language Learning: The Role of Memory Enhancement Techniques

    Ullman, Michael T.; Lovelett, Jarrett T.

    2018-01-01

    The declarative/procedural (DP) model posits that the learning, storage, and use of language critically depend on two learning and memory systems in the brain: declarative memory and procedural memory. Thus, on the basis of independent research on the memory systems, the model can generate specific and often novel predictions for language. Till…

  12. A Dosimetric Evaluation of Conventional Helmet Field Irradiation Versus Two-Field Intensity-Modulated Radiotherapy Technique

    Yu, James B.; Shiao, Stephen L.; Knisely, Jonathan

    2007-01-01

    Purpose: To compare dosimetric differences between conventional two-beam helmet field irradiation (external beam radiotherapy, EBRT) of the brain and a two-field intensity-modulated radiotherapy (IMRT) technique. Methods and Materials: Ten patients who received helmet field irradiation at our institution were selected for study. External beam radiotherapy portals were planned per usual practice. Intensity-modulated radiotherapy fields were created using the identical field angles as the EBRT portals. Each brain was fully contoured along with the spinal cord to the bottom of the C2 vertebral body. This volume was then expanded symmetrically by 0.5 cm to construct the planning target volume. An IMRT plan was constructed using uniform optimization constraints. For both techniques, the nominal prescribed dose was 3,000 cGy in 10 fractions of 300 cGy using 6-MV photons. Comparative dose-volume histograms were generated for each patient and analyzed. Results: Intensity-modulated radiotherapy improved dose uniformity over EBRT for whole brain radiotherapy. The mean percentage of brain receiving >105% of dose was reduced from 29.3% with EBRT to 0.03% with IMRT. The mean maximum dose was reduced from 3,378 cGy (113%) for EBRT to 3,162 cGy (105%) with IMRT. The mean percent volume receiving at least 98% of the prescribed dose was 99.5% for the conventional technique and 100% for IMRT. Conclusions: Intensity-modulated radiotherapy reduces dose inhomogeneity, particularly for the midline frontal lobe structures where hot spots occur with conventional two-field EBRT. More study needs to be done addressing the clinical implications of optimizing dose uniformity and its effect on long-term cognitive function in selected long-lived patients

  13. Heterogeneous chemical kinetics by modulated molecular beam mass spectrometry: limitations of technique

    Olander, D.R.

    1977-01-01

    The advantages and limitations of modulated molecular beam, mass spectrometry as applied to the study of heterogeneous chemical kinetics are reviewed. The process of deducing a model of the surface reaction from experimental data is illustrated by analysis of the hydrogen reduction of uranium dioxide

  14. Vapor Measurement System of Essential Oil Based on MOS Gas Sensors Driven with Advanced Temperature Modulation Technique

    Sudarmaji, A.; Margiwiyatno, A.; Ediati, R.; Mustofa, A.

    2018-05-01

    The aroma/vapor of essential oils is complex compound which depends on the content of the gases and volatiles generated from essential oil. This paper describes a design of quick, simple, and low-cost static measurement system to acquire vapor profile of essential oil. The gases and volatiles are captured in a chamber by means of 9 MOS gas sensors which driven with advance temperature modulation technique. A PSoC CY8C28445-24PVXI based-interface unit is built to generate the modulation signal and acquire all sensor output into computer wirelessly via radio frequency serial communication using Digi International Inc., XBee (IEEE 802.15.4) through developed software under Visual.Net. The system was tested to measure 2 kinds of essential oil (Patchouli and Clove Oils) in 4 temperature modulations (without, 0.25 Hz, 1 Hz, and 4 Hz). A cycle measurement consists of reference and sample measurement sequentially which is set during 2 minutes in every 1 second respectively. It is found that the suitable modulation is 0,25Hz; 75%, and the results of Principle Component Analysis show that the system is able to distinguish clearly between Patchouli Oil and Clove Oil.

  15. Forward Behavioral Modeling of a Three-Way Amplitude Modulator-Based Transmitter Using an Augmented Memory Polynomial

    Jatin Chatrath

    2018-03-01

    Full Text Available Reconfigurable and multi-standard RF front-ends for wireless communication and sensor networks have gained importance as building blocks for the Internet of Things. Simpler and highly-efficient transmitter architectures, which can transmit better quality signals with reduced impairments, are an important step in this direction. In this regard, mixer-less transmitter architecture, namely, the three-way amplitude modulator-based transmitter, avoids the use of imperfect mixers and frequency up-converters, and their resulting distortions, leading to an improved signal quality. In this work, an augmented memory polynomial-based model for the behavioral modeling of such mixer-less transmitter architecture is proposed. Extensive simulations and measurements have been carried out in order to validate the accuracy of the proposed modeling strategy. The performance of the proposed model is evaluated using normalized mean square error (NMSE for long-term evolution (LTE signals. NMSE for a LTE signal of 1.4 MHz bandwidth with 100,000 samples for digital combining and analog combining are recorded as −36.41 dB and −36.9 dB, respectively. Similarly, for a 5 MHz signal the proposed models achieves −31.93 dB and −32.08 dB NMSE using digital and analog combining, respectively. For further validation of the proposed model, amplitude-to-amplitude (AM-AM, amplitude-to-phase (AM-PM, and the spectral response of the modeled and measured data are plotted, reasonably meeting the desired modeling criteria.

  16. Application of the modulated temperature differential scanning calorimetry technique for the determination of the specific heat of copper nanofluids

    De Robertis, E.; Cosme, E.H.H.; Neves, R.S.; Kuznetsov, A.Yu.; Campos, A.P.C.; Landi, S.M.; Achete, C.A.

    2012-01-01

    The purpose of this work is to investigate the applicability of the modulated temperature differential scanning calorimetry technique to measure specific heat of copper nanofluids by using the ASTM E2719 standard procedure, which is generally applied to thermally stable solids and liquids. The one-step method of preparation of copper nanofluid samples is described. The synthesized nanoparticles were separated from the base fluid and examined by X-ray diffraction and transmission electron microscopy in order to evaluate their structure, morphology and chemical nature. The presence of copper nanoparticles in the base fluid alters the characteristics of crystallization and melting processes and reduces the specific heat values of nanofluids in the whole studied temperature range. - Highlights: ► Copper nanofluids prepared by one-step method. ► Methodology of synthesis improved nanofluid stability. ► Specific heat determinations using modulated temperature differential scanning calorimetry. ► Good agreement between theoretical and experimental values.

  17. Both a Nicotinic Single Nucleotide Polymorphism (SNP) and a Noradrenergic SNP Modulate Working Memory Performance when Attention is Manipulated

    Greenwood, Pamela M.; Sundararajan, Ramya; Lin, Ming-Kuan; Kumar, Reshma; Fryxell, Karl J.; Parasuraman, Raja

    2009-01-01

    We investigated the relation between the two systems of visuospatial attention and working memory by examining the effect of normal variation in cholinergic and noradrenergic genes on working memory performance under attentional manipulation. We previously reported that working memory for location was impaired following large location precues, indicating the scale of visuospatial attention has a role in forming the mental representation of the target. In one of the first studies to compare ef...

  18. Optimization of multiple-module thermoelectric coolers using artificial-intelligence techniques

    Chen, K. [University of Utah (United States). Dept. of Mechanical Engineering; Lin, G.T. [National Taiwan University of Science and Technology, Taipei (China). Dept. of Mechanical Engineering

    2002-07-01

    Genetic algorithm (GA) and simulated annealing (SA) methods were employed to optimize the current distribution of a cooler made up of a large number of thermoelectric (TE) modules. The TE modules were grouped into several clusters in the flow direction, and the electric currents supplied to different clusters were adjusted separately to achieve maximum energy efficiency or minimum refrigeration temperature for different,operating conditions and cooling requirements. Optimization results based on the design parameters of a large TE cooler showed considerable improvements in energy efficiency and refrigeration temperature when compared to the results of uniform current for the parallel-flow arrangement. On the other hand, results of the counter-flow arrangement showed only slight differences between uniform- and non-uniform-current optimizations. The optimization results of GA and SA were very close to each other. SA converged faster and was more computationally economical than GA for TE system optimization. (author)

  19. Percutaneous autonomic neural modulation: A novel technique to treat cardiac arrhythmia

    DeSimone, Christopher V.; Madhavan, Malini; Venkatachalam, Kalpathi L.; Knudson, Mark B.; Asirvatham, Samuel J.

    2013-01-01

    Ablation and anti-arrhythmic medications have shown promise but have been met with varying success and unwanted side effects such as myocardial injury, arrhythmias, and morbidity from invasive surgical intervention. The answer to improving efficacy of ablation may include modulation of the cardiac aspect of the autonomic nervous system. Our lab has developed a novel approach and device to navigate the oblique sinus and to use DC current and saline/alcohol irrigation to selectively stimulate and block the autonomic ganglia found on the epicardial side of the heart. This novel approach minimizes myocardial damage from thermal injury and provides a less invasive and targeted approach. For feasibility, proof-of-concept, and safety monitoring, we carried out canine studies to test this novel application. Our results suggest a safer and less invasive way of modulating arrhythmogenic substrate that may lead to improved treatment of AF in humans

  20. Percutaneous autonomic neural modulation: A novel technique to treat cardiac arrhythmia

    DeSimone, Christopher V.; Madhavan, Malini [Cardiovascular Diseases, Department of Medicine, Mayo Clinic, Rochester, MN (United States); Venkatachalam, Kalpathi L. [Cardiovascular Diseases, Department of Medicine, Mayo Clinic, Jacksonville, FL (United States); Knudson, Mark B. [Mayo Clinic, Rochester, MN (United States); EnteroMedics, EnteroMedics, St. Paul, MN (United States); Asirvatham, Samuel J., E-mail: asirvatham.samuel@mayo.edu [Cardiovascular Diseases, Department of Medicine, Mayo Clinic, Rochester, MN (United States); Pediatric Cardiology, Department of Pediatric and Adolescent Medicine, Mayo Clinic, Rochester, MN (United States)

    2013-05-15

    Ablation and anti-arrhythmic medications have shown promise but have been met with varying success and unwanted side effects such as myocardial injury, arrhythmias, and morbidity from invasive surgical intervention. The answer to improving efficacy of ablation may include modulation of the cardiac aspect of the autonomic nervous system. Our lab has developed a novel approach and device to navigate the oblique sinus and to use DC current and saline/alcohol irrigation to selectively stimulate and block the autonomic ganglia found on the epicardial side of the heart. This novel approach minimizes myocardial damage from thermal injury and provides a less invasive and targeted approach. For feasibility, proof-of-concept, and safety monitoring, we carried out canine studies to test this novel application. Our results suggest a safer and less invasive way of modulating arrhythmogenic substrate that may lead to improved treatment of AF in humans.

  1. Theoretical investigation of metal magnetic memory testing technique for detection of magnetic flux leakage signals from buried defect

    Xu, Kunshan; Qiu, Xingqi; Tian, Xiaoshuai

    2018-01-01

    The metal magnetic memory testing (MMMT) technique has been extensively applied in various fields because of its unique advantages of easy operation, low cost and high efficiency. However, very limited theoretical research has been conducted on application of MMMT to buried defects. To promote study in this area, the equivalent magnetic charge method is employed to establish a self-magnetic flux leakage (SMFL) model of a buried defect. Theoretical results based on the established model successfully capture basic characteristics of the SMFL signals of buried defects, as confirmed via experiment. In particular, the newly developed model can calculate the buried depth of a defect based on the SMFL signals obtained via testing. The results show that the new model can successfully assess the characteristics of buried defects, which is valuable in the application of MMMT in non-destructive testing.

  2. Operational parameters analysis of the radiographic technique through the modulation transfer function

    Motta, Mauricio Saldanha; Guimaraes, Ari Sauer

    1995-01-01

    The influence of the focal size and image magnification variations on the radiographic final image is studied. The analysis used the modulation transfer function for evaluating the ratio of the radiographic image amplitude and that of the inspected object. it was concluded that the increase of the focal size and of the magnifications are not good for the image quality. 3 refs., 4 figs., 1 tab

  3. DSP-based CSO cancellation technique for RoF transmission system implemented by using directly modulated laser.

    Kim, Byung Gon; Bae, Sung Hyun; Kim, Hoon; Chung, Yun C

    2017-05-29

    We propose and demonstrate a simple composite second-order (CSO) cancellation technique based on the digital signal processing (DSP) for the radio-over-fiber (RoF) transmission system implemented by using directly modulated lasers (DMLs). When the RoF transmission system is implemented by using DMLs, its performance could be limited by the CSO distortions caused by the interplay between the DML's chirp and fiber's chromatic dispersion. We present the theoretical analysis of these nonlinear distortions and show that they can be suppressed at the receiver by using a simple DSP. To verify the effectiveness of the proposed technique, we demonstrate the transmission of twenty-four 100-MHz filtered orthogonal frequency-division multiplexing (f-OFDM) signals in 64 quadrature amplitude modulation (QAM) format over 20 km of the standard single-mode fiber (SSMF). The results show that, by using the proposed technique, we can suppress the CSO distortion components by >10 dB and achieve the error-vector magnitude performance better than 6% even after the 20-km long SSMF transmission.

  4. Spacing Techniques in Second Language Vocabulary Acquisition: Short-Term Gains vs. Long-Term Memory

    Schuetze, Ulf

    2015-01-01

    This article reports the results of two experiments using the spacing technique (Leitner, 1972; Landauer & Bjork, 1978) in second language vocabulary acquisition. In the past, studies in this area have produced mixed results attempting to differentiate between massed, uniform and expanded intervals of spacing (Balota, Duchek, & Logan,…

  5. Virtual reality techniques in older adults: exposure therapy, memory training, and training of motor balance

    Meyerbröker, K.; Emmelkamp, P.M.G.; Pachana, N.A.; Laidlaw, K.

    2014-01-01

    We reviewed the literature on virtual reality techniques in older adults. Although treatment of specific phobias in older adults by virtual reality exposure therapy (VRET) is feasible and might be effective, this has yet not been evaluated in randomized controlled trials. The few controlled studies

  6. A comparative study of standard intensity-modulated radiotherapy and RapidArc planning techniques for ipsilateral and bilateral head and neck irradiation

    Pursley, Jennifer, E-mail: jpursley@mgh.harvard.edu [Department of Radiation Oncology, Dana-Farber Cancer Institute/Brigham and Women' s Hospital, Boston, MA (United States); Department of Radiation Oncology, Massachusetts General Hospital, Boston, MA (United States); Damato, Antonio L.; Czerminska, Maria A.; Margalit, Danielle N. [Department of Radiation Oncology, Dana-Farber Cancer Institute/Brigham and Women' s Hospital, Boston, MA (United States); Sher, David J. [Department of Radiation Oncology, Dana-Farber Cancer Institute/Brigham and Women' s Hospital, Boston, MA (United States); Department of Radiation Oncology, UT Southwestern Medical Center, Dallas, TX (United States); Tishler, Roy B. [Department of Radiation Oncology, Dana-Farber Cancer Institute/Brigham and Women' s Hospital, Boston, MA (United States)

    2017-04-01

    The purpose of this study was to investigate class solutions using RapidArc volumetric-modulated arc therapy (VMAT) planning for ipsilateral and bilateral head and neck (H&N) irradiation, and to compare dosimetric results with intensity-modulated radiotherapy (IMRT) plans. A total of 14 patients who received ipsilateral and 10 patients who received bilateral head and neck irradiation were retrospectively replanned with several volumetric-modulated arc therapy techniques. For ipsilateral neck irradiation, the volumetric-modulated arc therapy techniques included two 360° arcs, two 360° arcs with avoidance sectors around the contralateral parotid, two 260° or 270° arcs, and two 210° arcs. For bilateral neck irradiation, the volumetric-modulated arc therapy techniques included two 360° arcs, two 360° arcs with avoidance sectors around the shoulders, and 3 arcs. All patients had a sliding-window-delivery intensity-modulated radiotherapy plan that was used as the benchmark for dosimetric comparison. For ipsilateral neck irradiation, a volumetric-modulated arc therapy technique using two 360° arcs with avoidance sectors around the contralateral parotid was dosimetrically comparable to intensity-modulated radiotherapy, with improved conformity (conformity index = 1.22 vs 1.36, p < 0.04) and lower contralateral parotid mean dose (5.6 vs 6.8 Gy, p < 0.03). For bilateral neck irradiation, 3-arc volumetric-modulated arc therapy techniques were dosimetrically comparable to intensity-modulated radiotherapy while also avoiding irradiation through the shoulders. All volumetric-modulated arc therapy techniques required fewer monitor units than sliding-window intensity-modulated radiotherapy to deliver treatment, with an average reduction of 35% for ipsilateral plans and 67% for bilateral plans. Thus, for ipsilateral head and neck irradiation a volumetric-modulated arc therapy technique using two 360° arcs with avoidance sectors around the contralateral parotid is

  7. Intensity modulated radiation therapy for squamous cell carcinoma of the vulva: Treatment technique and outcomes

    Yuan James Rao, MD

    2017-04-01

    Conclusions: IMRT for vulvar cancer is associated with high rates of LRC in the postoperative setting and limited radiation-related toxicity. Durable LRC of disease after definitive IMRT remains challenging, and several refinements to our treatment technique are suggested.

  8. Modulation of memory with septal injections of morphine and glucose: effects on extracellular glucose levels in the hippocampus.

    McNay, Ewan C; Canal, Clinton E; Sherwin, Robert S; Gold, Paul E

    2006-02-28

    The concentration of glucose in the extracellular fluid (ECF) of the hippocampus decreases substantially during memory testing on a hippocampus-dependent memory task. Administration of exogenous glucose, which enhances task performance, prevents this decrease, suggesting a relationship between hippocampal glucose availability and memory performance. In the present experiment, spontaneous alternation performance and task-related changes in hippocampal ECF glucose were assessed in rats after intraseptal administration of morphine, which impairs memory on a spontaneous alternation task, and after co-administration of intraseptal glucose, which attenuates that impairment. Consistent with previous findings, spontaneous alternation testing resulted in a decrease in hippocampal ECF glucose levels in control rats. However, rats that received intraseptal morphine prior to testing showed memory impairments and an absence of the task-related decrease in hippocampal ECF glucose levels. Intraseptal co-administration of glucose with morphine attenuated the memory impairment, and ECF glucose levels in the hippocampus decreased in a manner comparable to that seen in control rats. These data suggest that fluctuations in hippocampal ECF glucose levels may be a marker of mnemonic processing and support the view that decreases in extracellular glucose during memory testing reflect increased glucose demand during memory processing.

  9. Dopamine D1 Sensitivity in the Prefrontal Cortex Predicts General Cognitive Abilities and is Modulated by Working Memory Training

    Wass, Christopher; Pizzo, Alessandro; Sauce, Bruno; Kawasumi, Yushi; Sturzoiu, Tudor; Ree, Fred; Otto, Tim; Matzel, Louis D.

    2013-01-01

    A common source of variance (i.e., "general intelligence") underlies an individual's performance across diverse tests of cognitive ability, and evidence indicates that the processing efficacy of working memory may serve as one such source of common variance. One component of working memory, selective attention, has been reported to…

  10. A simple microwave technique for plasma density measurement using frequency modulation

    Bora, D.; Jayakumar, R.; Vijayashankar, M.K.

    1984-01-01

    A simple method of determining the phase variation unambiguously during microwave interferometric measurement is described. The frequency of the Klystron source is modulated with the help of staircase voltage pulse. The height of each stair is adjusted such that the corresponding phase shift in the test branch with an additional path length is 90 0 . Signals, proportional to cosine and sine of the phase shift due to plasma, can be generated in the same channel and plasma density information can be inferred. The microwave hardware remains the same as in conventional interferometry and the cost of such a scheme is low. (author)

  11. Contrast and resolution enhancement of a near-field optical microscope by using a modulation technique

    Flaxer, Eli; Palachi, Eldad

    2005-01-01

    A new design of a tunneling near-field optical microscope (TNOM) combined with an atomic force microscope (AFM) is presented. This design can be used to generate three different images of the sample's surface: a non-contact (tapping mode) AFM image, a conventional TNOM and an image of a modulation signal of the conventional TNOM, which we call AC-TNOM. The images are obtained simultaneously, using a single light source. It is shown that the AC-TNOM has better resolution (∼200 A) and contrast compared to conventional TNOM (∼400 A)

  12. Measurement of LHCD edge power deposition through modulation techniques on Alcator C-Mod

    Faust, I. C.; Brunner, D.; LaBombard, B.; Parker, R. R.; Baek, S. G.; Chilenksi, M. A.; Hubbard, A.; Hughes, J. W.; Terry, J. L.; Shiraiwa, S.; Walk, J. R.; Wallace, G. M.; Whyte, D. G. [MIT Plasma Science and Fusion Center, Cambridge, MA USA (United States); Edlund, E. [Princeton Plasma Physics Laboratory, Princeton, NJ USA (United States)

    2015-12-10

    The efficiency of LHCD on Alcator C-Mod drops exponentially with line average density. At reactor relevant densities (> 1 · 1020 [m{sup −3}]) no measurable current is driven. While a number of causes have been suggested, no specific mechanism has been shown to be responsible for the loss of current drive at high density. Fast modulation of the LH power was used to isolate and quantify the LHCD deposition within the plasma. Measurements from these plasmas provide unique evidence for determining a root cause. Modulation of LH power in steady plasmas exhibited no correlated change in the core temperature. A correlated, prompt response in the edge suggests that the loss in efficiency is related to a edge absorption mechanism. This follows previous results which found the generation of n{sub ||}-independent SOL currents. Multiple Langmuir probe array measurements of the conducted heat conclude that the lost power is deposited near the last closed flux surface. The heat flux induced by LH waves onto the outer divertor is calculated. Changes in the neutral pressure, ionization and hard X-ray emission at high density highlight the importance of the active divertor in the loss of efficiency. Results of this study implicate a mechanism which may occur over multiple passes, leading to power absorption near the LCFS.

  13. Simple Carotid-Sparing Intensity-Modulated Radiotherapy Technique and Preliminary Experience for T1-2 Glottic Cancer

    Rosenthal, David I.; Fuller, Clifton D.; Barker, Jerry L.; Mason, Bryan M.S.; Garcia, John A. C.; Lewin, Jan S.; Holsinger, F. Christopher; Stasney, C. Richard; Frank, Steven J.; Schwartz, David L.; Morrison, William H.; Garden, Adam S.; Ang, K. Kian

    2010-01-01

    Purpose: To investigate the dosimetry and feasibility of carotid-sparing intensity-modulated radiotherapy (IMRT) for early glottic cancer and to report preliminary clinical experience. Methods and Materials: Digital Imaging and Communications in Medicine radiotherapy (DICOM-RT) datasets from 6 T1-2 conventionally treated glottic cancer patients were used to create both conventional IMRT plans. We developed a simplified IMRT planning algorithm with three fields and limited segments. Conventional and IMRT plans were compared using generalized equivalent uniform dose and dose-volume parameters for in-field carotid arteries, target volumes, and organs at risk. We have treated 11 patients with this simplified IMRT technique. Results: Intensity-modulated radiotherapy consistently reduced radiation dose to the carotid arteries (p < 0.05) while maintaining the clinical target volume coverage. With conventional planning, median carotid V35, V50, and V63 were 100%, 100%, and 69.0%, respectively. With IMRT planning these decreased to 2%, 0%, and 0%, respectively (p < 0.01). Radiation planning and treatment times were similar for conventional radiotherapy and IMRT. Treatment results have been excellent thus far. Conclusions: Intensity-modulated radiotherapy significantly reduced unnecessary radiation dose to the carotid arteries compared with conventional lateral fields while maintaining clinical target volume coverage. Further experience and longer follow-up will be required to demonstrate outcomes for cancer control and carotid artery effects.

  14. Short-term testosterone manipulations modulate visual recognition memory and some aspects of emotional reactivity in male rhesus monkeys.

    Lacreuse, Agnès; Gore, Heather E; Chang, Jeemin; Kaplan, Emily R

    2012-05-15

    The role of testosterone (T) in modulating cognitive function and emotion in men remains unclear. The paucity of animal studies has likely contributed to the slow progress in this area. In particular, studies in nonhuman primates have been lacking. Our laboratory has begun to address this issue by pharmacologically manipulating T levels in intact male rhesus monkeys, using blind, placebo-controlled, crossover designs. We previously found that T-suppressed monkeys receiving supraphysiological T for 4 weeks had lower visual recognition memory for long delays and enhanced attention to videos of negative social stimuli (Lacreuse et al., 2009, 2010) compared to when treated with oil. To further delineate the conditions under which T affects cognition and emotion, the present study focused on the short-term effects of physiological T. Six intact males were treated with the gonadotropin-releasing hormone antagonist degarelix (3 mg/kg) for 7 days and received one injection of T enanthate (5 mg/kg) followed by one injection of oil vehicle 7 days later (n=3), or the reverse treatment (n=3). Performance on two computerized tasks, the Delayed-non-matching-to-sample (DNMS) with random delays and the object-Delayed Recognition Span test (object-DRST) and one task of emotional reactivity, an approach/avoidance task of negative, familiar and novel objects, was examined at baseline and 3-5 days after treatment. DNMS performance was significantly better when monkeys were treated with T compared to oil, independently of the delay duration or the nature (emotional or neutral) of the stimuli. Performance on the object-DRST was unaffected. Interestingly, subtle changes in emotional reactivity were also observed: T administration was associated with fewer object contacts, especially on negative objects, without overt changes in anxious behaviors. These results may reflect increased vigilance and alertness with high T. Altogether, the data suggest that changes in general arousal may

  15. Grapefruit (Citrus paradisi Macfad) phytochemicals composition is modulated by household processing techniques.

    Uckoo, Ram M; Jayaprakasha, Guddadarangavvanahally K; Balasubramaniam, V M; Patil, Bhimanagouda S

    2012-09-01

    Grapefruits (Citrus paradisi Macfad) contain several phytochemicals known to have health maintaining properties. Due to the consumer's interest in obtaining high levels of these phytochemicals, it is important to understand the changes in their levels by common household processing techniques. Therefore, mature Texas "Rio Red" grapefruits were processed by some of the common household processing practices such as blending, juicing, and hand squeezing techniques and analyzed for their phytochemical content by high performance liquid chromatography (HPLC). Results suggest that grapefruit juice processed by blending had significantly (P levels of flavonoids (narirutin, naringin, hesperidin, neohesperidin, didymin, and poncirin) and limonin compared to juicing and hand squeezing. No significant variation in their content was noticed in the juice processed by juicing and hand squeezing. Ascorbic acid and citric acid were significantly (P processed by juicing and blending, respectively. Furthermore, hand squeezed fruit juice had significantly higher contents of dihydroxybergamottin (DHB) than juice processed by juicing and blending. Bergamottin and 5-methoxy-7 gernoxycoumarin (5-M-7-GC) were significantly higher in blended juice compared to juicing and hand squeezing. Therefore, consuming grapefruit juice processed by blending may provide higher levels of health beneficial phytochemicals such as naringin, narirutin, and poncirin. In contrast, juice processed by hand squeezing and juicing provides lower levels of limonin, bergamottin, and 5-M-7-GC. These results suggest that, processing techniques significantly influence the levels of phytochemicals and blending is a better technique for obtaining higher levels of health beneficial phytochemicals from grapefruits. Practical Application:  Blending, squeezing, and juicing are common household processing techniques used for obtaining fresh grapefruit juice. Understanding the levels of health beneficial phytochemicals

  16. Modulating Memory Performance in Healthy Subjects with Transcranial Direct Current Stimulation Over the Right Dorsolateral Prefrontal Cortex.

    Smirni, Daniela; Turriziani, Patrizia; Mangano, Giuseppa Renata; Cipolotti, Lisa; Oliveri, Massimiliano

    2015-01-01

    The role of the Dorsolateral Prefrontal Cortex (DLPFC) in recognition memory has been well documented in lesion, neuroimaging and repetitive Transcranial Magnetic Stimulation (rTMS) studies. The aim of the present study was to investigate the effects of transcranial Direct Current Stimulation (tDCS) over the left and the right DLPFC during the delay interval of a non-verbal recognition memory task. 36 right-handed young healthy subjects participated in the study. The experimental task was an Italian version of Recognition Memory Test for unknown faces. Study included two experiments: in a first experiment, each subject underwent one session of sham tDCS and one session of left or right cathodal tDCS; in a second experiment each subject underwent one session of sham tDCS and one session of left or right anodal tDCS. Cathodal tDCS over the right DLPFC significantly improved non verbal recognition memory performance, while cathodal tDCS over the left DLPFC had no effect. Anodal tDCS of both the left and right DLPFC did not modify non verbal recognition memory performance. Complementing the majority of previous studies, reporting long term memory facilitations following left prefrontal anodal tDCS, the present findings show that cathodal tDCS of the right DLPFC can also improve recognition memory in healthy subjects.

  17. A microcomputer-controlled modulation technique for the detection of transient species in UV photoelectron spectroscopy

    Lonkhuyzen, H. van; Muller, H.G.; Lange, C.A. de

    1980-01-01

    A microcomputer-controlled modulation method is described to measure UV photoelectron spectra of transient species generated in a microwave discharge. Spectra at low and high microwave power levels are simultaneously recorded and afterwards linearly combined in order to remove parent compound signals. The method is applied to discharged oxygen where the transition O 2 + ( 2 PHIsub(u)) 2 ( 1 Δsub(g)) becomes visible without interference from the parent molecule O 2 ( 3 Σsub(g) - ), and to discharged sulphur dioxide where SO( 3 Σ - ) and S( 3 P) photoelectron spectra are obtained free from SO 2 bands. Finally the build-up of transient bands as a function of time is recorded. (orig.)

  18. Optical techniques to feed and control GaAs MMIC modules for phased array antenna applications

    Bhasin, K. B.; Anzic, G.; Kunath, R. R.; Connolly, D. J.

    1986-01-01

    A complex signal distribution system is required to feed and control GaAs monolithic microwave integrated circuits (MMICs) for phased array antenna applications above 20 GHz. Each MMIC module will require one or more RF lines, one or more bias voltage lines, and digital lines to provide a minimum of 10 bits of combined phase and gain control information. In a closely spaced array, the routing of these multiple lines presents difficult topology problems as well as a high probability of signal interference. To overcome GaAs MMIC phased array signal distribution problems optical fibers interconnected to monolithically integrated optical components with GaAs MMIC array elements are proposed as a solution. System architecture considerations using optical fibers are described. The analog and digital optical links to respectively feed and control MMIC elements are analyzed. It is concluded that a fiber optic network will reduce weight and complexity, and increase reliability and performance, but higher power will be required.

  19. Radiation-Induced Cancers From Modern Radiotherapy Techniques: Intensity-Modulated Radiotherapy Versus Proton Therapy

    Yoon, Myonggeun; Ahn, Sung Hwan; Kim, Jinsung; Shin, Dong Ho; Park, Sung Yong; Lee, Se Byeong; Shin, Kyung Hwan; Cho, Kwan Ho

    2010-01-01

    Purpose: To assess and compare secondary cancer risk resulting from intensity-modulated radiotherapy (IMRT) and proton therapy in patients with prostate and head-and-neck cancer. Methods and Materials: Intensity-modulated radiotherapy and proton therapy in the scattering mode were planned for 5 prostate caner patients and 5 head-and-neck cancer patients. The secondary doses during irradiation were measured using ion chamber and CR-39 detectors for IMRT and proton therapy, respectively. Organ-specific radiation-induced cancer risk was estimated by applying organ equivalent dose to dose distributions. Results: The average secondary doses of proton therapy for prostate cancer patients, measured 20-60cm from the isocenter, ranged from 0.4 mSv/Gy to 0.1 mSv/Gy. The average secondary doses of IMRT for prostate patients, however, ranged between 3 mSv/Gy and 1 mSv/Gy, approximately one order of magnitude higher than for proton therapy. Although the average secondary doses of IMRT were higher than those of proton therapy for head-and-neck cancers, these differences were not significant. Organ equivalent dose calculations showed that, for prostate cancer patients, the risk of secondary cancers in out-of-field organs, such as the stomach, lungs, and thyroid, was at least 5 times higher for IMRT than for proton therapy, whereas the difference was lower for head-and-neck cancer patients. Conclusions: Comparisons of organ-specific organ equivalent dose showed that the estimated secondary cancer risk using scattering mode in proton therapy is either significantly lower than the cases in IMRT treatment or, at least, does not exceed the risk induced by conventional IMRT treatment.

  20. Nonvolatile memory thin film transistors using CdSe/ZnS quantum dot-poly(methyl methacrylate) composite layer formed by a two-step spin coating technique

    Chen, Ying-Chih; Huang, Chun-Yuan; Yu, Hsin-Chieh; Su, Yan-Kuin

    2012-08-01

    The nonvolatile memory thin film transistors (TFTs) using a core/shell CdSe/ZnS quantum dot (QD)-poly(methyl methacrylate) (PMMA) composite layer as the floating gate have been demonstrated, with the device configuration of n+-Si gate/SiO2 insulator/QD-PMMA composite layer/pentacene channel/Au source-drain being proposed. To achieve the QD-PMMA composite layer, a two-step spin coating technique was used to successively deposit QD-PMMA composite and PMMA on the insulator. After the processes, the variation of crystal quality and surface morphology of the subsequent pentacene films characterized by x-ray diffraction spectra and atomic force microscopy was correlated to the two-step spin coating. The crystalline size of pentacene was improved from 147.9 to 165.2 Å, while the degree of structural disorder was decreased from 4.5% to 3.1% after the adoption of this technique. In pentacene-based TFTs, the improvement of the performance was also significant, besides the appearances of strong memory characteristics. The memory behaviors were attributed to the charge storage/discharge effect in QD-PMMA composite layer. Under the programming and erasing operations, programmable memory devices with the memory window (Δ Vth) = 23 V and long retention time were obtained.

  1. Emotional face expression modulates occipital-frontal effective connectivity during memory formation in a bottom-up fashion

    Daiming eXiu

    2015-04-01

    Full Text Available This study investigated the role of bottom-up and top-down neural mechanisms in the processing of emotional face expression during memory formation. Functional brain imaging data was acquired during incidental learning of positive (‘happy’, neutral and negative (‘angry’ or ‘fearful’ faces. Dynamic Causal Modeling (DCM was applied on the fMRI data to characterize effective connectivity within a brain network involving face perception (inferior occipital gyrus and fusiform gyrus and successful memory formation related areas (hippocampus, superior parietal lobule, amygdala and orbitofrontal cortex. The bottom-up models assumed processing of emotional face expression along feed forward pathways to the orbitofrontal cortex. The top-down models assumed that the orbitofrontal cortex processed emotional valence and mediated connections to the hippocampus. A subsequent recognition memory test showed an effect of negative emotion on the response bias, but not on memory performance. Our DCM findings showed that the bottom-up model family of effective connectivity best explained the data across all subjects and specified that emotion affected most bottom-up connections to the orbitofrontal cortex, especially from the occipital visual cortex and superior parietal lobule. Of those pathways to the orbitofrontal cortex the connection from the inferior occipital gyrus correlated with memory performance independently of valence. We suggest that bottom-up neural mechanisms support effects of emotional face expression and memory formation in a parallel and partially overlapping fashion.

  2. Segmental and dynamic intensity-modulated radiotherapy delivery techniques for micro-multileaf collimator

    Agazaryan, Nzhde; Solberg, Timothy D.

    2003-01-01

    A leaf sequencing algorithm has been implemented to deliver segmental and dynamic multileaf collimated intensity-modulated radiotherapy (SMLC-IMRT and DMLC-IMRT, respectively) using a linear accelerator equipped with a micro-multileaf collimator (mMLC). The implementation extends a previously published algorithm for the SMLC-IMRT to include the dynamic MLC-IMRT method and several dosimetric considerations. The algorithm has been extended to account for the transmitted radiation and minimize the leakage between opposing and neighboring leaves. The underdosage problem associated with the tongue-and-groove design of the MLC is significantly reduced by synchronizing the MLC leaf movements. The workings of the leaf sequencing parameters have been investigated and the results of the planar dosimetric investigations show that the sequencing parameters affect the measured dose distributions as intended. Investigations of clinical cases suggest that SMLC and DMLC delivery methods produce comparable results with leaf sequences obtained by root-mean-square (RMS) errors specification of 1.5% and lower, approximately corresponding to 20 or more segments. For SMLC-IMRT, there is little to be gained by using an RMS error specification smaller than 2%, approximately corresponding to 15 segments; however, more segments directly translate to longer treatment time and more strain on the MLC. The implemented leaf synchronization method does not increase the required monitor units while it reduces the measured TG underdoses from a maximum of 12% to a maximum of 3% observed with single field measurements of representative clinical cases studied

  3. Developing a Virtual Teach-To-Goal™ Inhaler Technique Learning Module: A Mixed Methods Approach.

    Wu, Meng; Woodrick, Nicole M; Arora, Vineet M; Farnan, Jeanne M; Press, Valerie G

    Most hospitalized patients with asthma or chronic obstructive pulmonary disease misuse respiratory inhalers. An in-person educational strategy, teach-to-goal (TTG), improves inpatients' inhaler technique. To develop an effective, portable education intervention that remains accessible to hospitalized patients postdischarge for reinforcement of proper inhaler technique. A mixed methods approach at an urban academic hospital was used to iteratively develop, modify, and test a virtual teach-to-goal ™ (V-TTG ™ ) educational intervention using patient end-user feedback. A survey examined access and willingness to use technology for self-management education. Focus groups evaluated patients' feedback on access, functionality, and quality of V-TTG ™ . Forty-eight participants completed the survey, with most reporting having Internet access; 77% used the Internet at home and 82% used the Internet at least once every few weeks. More than 80% reported that they were somewhat or very likely to use V-TTG ™ to gain skills to improve their health. Most participants reported smartphone access (73%); half owned laptop computers (52%). Participants with asthma versus chronic obstructive pulmonary disease were more likely to own a smartphone, have a data plan, and have daily Internet use (P platform and delivery, Internet access, and technological literacy; functionality-usefulness, content, and teaching strategy; and quality-clarity, ease of use, length, and likability. V-TTG ™ is a promising educational tool for improving patients' inhaler technique, iteratively developed and refined with patient input. Patients in our urban, academic hospital overwhelmingly reported access to platforms and willingness to use V-TTG ™ for health education. Copyright © 2017 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

  4. The Factors Affecting the Sensitivity of the Ultrasonic Inter-Modulation Technique

    Courtney, C. R. P.; Drinkwater, B. W.; Neild, S. A.; Wilcox, P. D.

    2007-01-01

    A global non-destructive testing technique for detecting cracks in metal parts has been developed and the factors affecting its sensitivity investigated. A sample is excited at very-high-order modes of vibration at two frequencies and the frequency mixing measured. Experiments with fatigue-cracked steel beams demonstrate that these defects produce a strong mixing effect and that the signal relating to the frequency mixing is sensitive to the length of the crack. The sensitivity is also shown to be reliant on the modes of vibration used

  5. Study of thermal transitions in polymers by a multifrequency modulated DSC technique

    Fraga Rivas, Iria

    2010-01-01

    Premi extraordinari doctorat curs 2009-2010, àmbit de Ciències Differential Scanning Calorimetry (DSC) is one of the most widely used thermal analysis techniques for the study of transitions and relaxation processes in polymers and also in other materials. It measures the heat flow as a function of time and/or temperature, and determines the energy released or absorbed by a sample when it is heated (cooled) or maintained at a constant temperature. Its advantages are that it is fast a...

  6. Neutron spectral modulation as a new thermal neutron scattering technique. Pt. 1

    Ito, Y.; Nishi, M.; Motoya, K.

    1982-01-01

    A thermal neutron scattering technique is presented based on a new idea of labelling each neutron in its spectral position as well as in time through the scattering process. The method makes possible the simultaneous determination of both the accurate dispersion relation and its broadening by utilizing the resolution cancellation property of zero-crossing points in the cross-correlated time spectrum together with the Fourier transform scheme of the neutron spin echo without resorting to the echoing. The channel Fourier transform applied to the present method also makes possible the determination of the accurate direct energy scan profile of the scattering function with a rather broad incident neutron wavelength distribution. Therefore the intensity sacrifice for attaining high accurarcy is minimized. The technique is used with either a polarized or unpolarized beam at the sample position with no precautions against beam depolarization at the sample for the latter case. Relative time accurarcy of the order of 10 -3 to 10 -4 may be obtained for the general dispersion relation and for the quasi-elastic energy transfers using correspondingly the relative incident neutron wavelength spread of 10 to 1% around an incident neutron energy of a few meV. (orig.)

  7. CRTC1 Nuclear Translocation Following Learning Modulates Memory Strength via Exchange of Chromatin Remodeling Complexes on the Fgf1 Gene

    Shusaku Uchida

    2017-01-01

    Full Text Available Summary: Memory is formed by synapse-to-nucleus communication that leads to regulation of gene transcription, but the identity and organizational logic of signaling pathways involved in this communication remain unclear. Here we find that the transcription cofactor CRTC1 is a critical determinant of sustained gene transcription and memory strength in the hippocampus. Following associative learning, synaptically localized CRTC1 is translocated to the nucleus and regulates Fgf1b transcription in an activity-dependent manner. After both weak and strong training, the HDAC3-N-CoR corepressor complex leaves the Fgf1b promoter and a complex involving the translocated CRTC1, phosphorylated CREB, and histone acetyltransferase CBP induces transient transcription. Strong training later substitutes KAT5 for CBP, a process that is dependent on CRTC1, but not on CREB phosphorylation. This in turn leads to long-lasting Fgf1b transcription and memory enhancement. Thus, memory strength relies on activity-dependent changes in chromatin and temporal regulation of gene transcription on specific CREB/CRTC1 gene targets. : Uchida et al. link CRTC1 synapse-to-nucleus shuttling in memory. Weak and strong training induce CRTC1 nuclear transport and transient Fgf1b transcription by a complex including CRTC1, CREB, and histone acetyltransferase CBP, whereas strong training alone maintains Fgf1b transcription through CRTC1-dependent substitution of KAT5 for CBP, leading to memory enhancement. Keywords: memory enhancement, long-term potentiation, hippocampus, nuclear transport, epigenetics, FGF1, CRTC1, KAT5/Tip60, HDAC3, CREB

  8. Evaluation of two tomotherapy-based techniques for the delivery of whole-breast intensity-modulated radiation therapy

    Gonzalez, Victor J.; Buchholz, Daniel J.; Langen, Katja M.; Olivera, Gustavo H.; Chauhan, Bhavin; Meeks, Sanford L.; Ruchala, Kenneth J.; Haimerl, Jason; Lu Weiguo; Kupelian, Patrick A.

    2006-01-01

    Purpose: To evaluate two different techniques for whole-breast treatments delivered using the Hi-ART II tomotherapy device. Methods and Materials: Tomotherapy uses the standard rotational helical delivery. Topotherapy uses a stationary gantry while delivering intensity-modulated treatments. CT scans from 5 breast cancer patients were used. The prescription dose was 50.4 Gy. Results: On average, 99% of the target volume received 95% of prescribed dose with either technique. If treatment times are restricted to less than 9 min, the average percentage ipsilateral lung receiving ≥20 Gy was 22% for tomotherapy vs. 10% for topotherapy. The ipsilateral lung receiving ≥50.4 Gy was 4 cc for tomotherapy vs. 27 cc for topotherapy. The percentage of left ventricle receiving ≥30 Gy was 14% with tomotherapy vs. 4% for topotherapy. The average doses to the contralateral breast and lung were 0.6 and 0.8 Gy, respectively, for tomotherapy vs. 0.4 and 0.3 Gy for topotherapy. Conclusions: Tomotherapy provides improved target dose homogeneity and conformality over topotherapy. If delivery times are restricted, topotherapy reduces the amount of heart and ipsilateral lung volumes receiving low doses. For whole-breast treatments, topotherapy is an efficient technique that achieves adequate target uniformity while maintaining low doses to sensitive structures

  9. A Novel Heterocyclic Compound CE-104 Enhances Spatial Working Memory in the Radial Arm Maze in Rats and Modulates the Dopaminergic System.

    Aher, Yogesh D; Subramaniyan, Saraswathi; Shanmugasundaram, Bharanidharan; Sase, Ajinkya; Saroja, Sivaprakasam R; Holy, Marion; Höger, Harald; Beryozkina, Tetyana; Sitte, Harald H; Leban, Johann J; Lubec, Gert

    2016-01-01

    Various psychostimulants targeting monoamine neurotransmitter transporters (MATs) have been shown to rescue cognition in patients with neurological disorders and improve cognitive abilities in healthy subjects at low doses. Here, we examined the effects upon cognition of a chemically synthesized novel MAT inhibiting compound 2-(benzhydrylsulfinylmethyl)-4-methylthiazole (named as CE-104). The efficacy of CE-104 in blocking MAT [dopamine transporter (DAT), serotonin transporter (SERT), and norepinephrine transporter] was determined using in vitro neurotransmitter uptake assay. The effect of the drug at low doses (1 and 10 mg/kg) on spatial memory was studied in male rats in the radial arm maze (RAM). Furthermore, the dopamine receptor and transporter complex levels of frontal cortex (FC) tissue of trained and untrained animals treated either with the drug or vehicle were quantified on blue native PAGE (BN-PAGE). The drug inhibited dopamine (IC50: 27.88 μM) and norepinephrine uptake (IC50: 160.40 μM), but had a negligible effect on SERT. In the RAM, both drug-dose groups improved spatial working memory during the performance phase of RAM as compared to vehicle. BN-PAGE Western blot quantification of dopamine receptor and transporter complexes revealed that D1, D2, D3, and DAT complexes were modulated due to training and by drug effects. The drug's ability to block DAT and its influence on DAT and receptor complex levels in the FC is proposed as a possible mechanism for the observed learning and memory enhancement in the RAM.

  10. [Effect of serotonin-modulated anticonsolidation protein on formation of long-term memory in carps Cyprinus carpio in the model of active avoidance learning].

    Garina, D V; Mekhtiev, A A

    2014-01-01

    Effect of serotonin-modulated anticonsolidation protein (SMAP) that has property of disturbing formation of memory trace in mammals and of learning and memory in teleost fish was studied in the model of active avoidance learning. The experiment was performed in three stages: (1) fry of carps Cyprinus carpio L. was injected intracerebrovenricularly with the SMAP protein at a dose of 0.3 μg/g; control individuals were administered with equal amount of the buffered saline for poikilothermic animals; (2) 24 h after the injection, fish were learnt during 8 sèances for 2 days the conditioned reflex of active avoidance; (3) 48 h after the learning the testing of the skill was performed. The administration of the protein was shown to lead to disturbance of reproduction of the skill in the fish: the latent time of the skill reproduction in experimental individuals exceeded that in control fish more than two times, while the number of individuals succeeding the task in the experimental group was non-significantly lower than in the control group. However, unlike mammals, injection of the SMAP protein in this model produced no effect on the process of learning in carps. Thus, there was first demonstrated the inhibiting effect of the SMAP protein whose concentration correlated positively with the content of the neurotransmitter serotonin in brain on consolidation of memory traces in teleost fish.

  11. Basolateral amygdala bidirectionally modulates stress-induced hippocampal learning and memory deficits through a p25/Cdk5-dependent pathway.

    Rei, Damien; Mason, Xenos; Seo, Jinsoo; Gräff, Johannes; Rudenko, Andrii; Wang, Jun; Rueda, Richard; Siegert, Sandra; Cho, Sukhee; Canter, Rebecca G; Mungenast, Alison E; Deisseroth, Karl; Tsai, Li-Huei

    2015-06-09

    Repeated stress has been suggested to underlie learning and memory deficits via the basolateral amygdala (BLA) and the hippocampus; however, the functional contribution of BLA inputs to the hippocampus and their molecular repercussions are not well understood. Here we show that repeated stress is accompanied by generation of the Cdk5 (cyclin-dependent kinase 5)-activator p25, up-regulation and phosphorylation of glucocorticoid receptors, increased HDAC2 expression, and reduced expression of memory-related genes in the hippocampus. A combination of optogenetic and pharmacosynthetic approaches shows that BLA activation is both necessary and sufficient for stress-associated molecular changes and memory impairments. Furthermore, we show that this effect relies on direct glutamatergic projections from the BLA to the dorsal hippocampus. Finally, we show that p25 generation is necessary for the stress-induced memory dysfunction. Taken together, our data provide a neural circuit model for stress-induced hippocampal memory deficits through BLA activity-dependent p25 generation.

  12. ADRA2B genotype modulates effects of acute psychosocial stress on emotional memory retrieval in healthy young men.

    Li, Shijia; Weerda, Riklef; Guenzel, Friederike; Wolf, Oliver T; Thiel, Christiane M

    2013-07-01

    Previous studies have shown that acute psychosocial stress impairs retrieval of declarative memory with emotional material being especially sensitive to this effect. A functional deletion variant of the ADRA2B gene encoding the α2B-adrenergic receptor has been shown to increase emotional memory and neural activity in the amygdala. We investigated the effects of acute psychosocial stress and the ADRA2B allele on recognition memory for emotional and neutral faces. Fourty-two healthy, non-smoker male volunteers (30 deletion carriers, 12 noncarriers) were tested with a face recognition paradigm. During encoding they were presented with emotional and neutral faces. One hour later, participants underwent either a stress ("Trier Social Stress Test (TSST)") or a control procedure which was followed immediately by the retrieval session where subjects had to indicate whether the presented face was old or new. Stress increased salivary cortisol concentrations, blood pressure and pulse and impaired recognition memory for faces independent of emotional valence and genotype. Participants showed generally slower reaction times to emotional faces. Carriers of the ADRA2B functional deletion variant showed an impaired recognition and slower retrieval of neutral faces under stress. Further, they were significantly slower in retrieving fearful faces in the control condition. The findings indicate that a genetic variation of the noradrenergic system may preserve emotional faces from stress-induced memory impairments seen for neutral faces and heighten reactivity to emotional stimuli under control conditions. Copyright © 2013 Elsevier Inc. All rights reserved.

  13. Basolateral amygdala bidirectionally modulates stress-induced hippocampal learning and memory deficits through a p25/Cdk5-dependent pathway

    Rei, Damien; Mason, Xenos; Seo, Jinsoo; Gräff, Johannes; Rudenko, Andrii; Wang, Jun; Rueda, Richard; Siegert, Sandra; Cho, Sukhee; Canter, Rebecca G.; Mungenast, Alison E.; Deisseroth, Karl; Tsai, Li-Huei

    2015-01-01

    Repeated stress has been suggested to underlie learning and memory deficits via the basolateral amygdala (BLA) and the hippocampus; however, the functional contribution of BLA inputs to the hippocampus and their molecular repercussions are not well understood. Here we show that repeated stress is accompanied by generation of the Cdk5 (cyclin-dependent kinase 5)-activator p25, up-regulation and phosphorylation of glucocorticoid receptors, increased HDAC2 expression, and reduced expression of memory-related genes in the hippocampus. A combination of optogenetic and pharmacosynthetic approaches shows that BLA activation is both necessary and sufficient for stress-associated molecular changes and memory impairments. Furthermore, we show that this effect relies on direct glutamatergic projections from the BLA to the dorsal hippocampus. Finally, we show that p25 generation is necessary for the stress-induced memory dysfunction. Taken together, our data provide a neural circuit model for stress-induced hippocampal memory deficits through BLA activity-dependent p25 generation. PMID:25995364

  14. Loss of object recognition memory produced by extended access to methamphetamine self-administration is reversed by positive allosteric modulation of metabotropic glutamate receptor 5.

    Reichel, Carmela M; Schwendt, Marek; McGinty, Jacqueline F; Olive, M Foster; See, Ronald E

    2011-03-01

    Chronic methamphetamine (meth) abuse can lead to persisting cognitive deficits. Here, we utilized a long-access meth self-administration (SA) protocol to assess recognition memory and metabotropic glutamate receptor (mGluR) expression, and the possible reversal of cognitive impairments with the mGluR5 allosteric modulator, 3-cyano-N-(1,3-diphenyl-1H-pyrazol-5-yl) benzamide (CDPPB). Male, Long-Evans rats self-administered i.v. meth (0.02 mg/infusion) on an FR1 schedule of reinforcement or received yoked-saline infusions. After seven daily 1-h sessions, rats were switched to 6-h daily sessions for 14 days, and then underwent drug abstinence. Rats were tested for object recognition memory at 1 week after meth SA at 90 min and 24 h retention intervals. In a separate experiment, rats underwent the same protocol, but received either vehicle or CDPPB (30 mg/kg) after familiarization. Rats were killed on day 8 or 14 post-SA and brain tissue was obtained. Meth intake escalated over the extended access period. Additionally, meth-experienced rats showed deficits in both short- and long-term recognition memory, demonstrated by a lack of novel object exploration. The deficit at 90 min was reversed by CDPPB treatment. On day 8, meth intake during SA negatively correlated with mGluR expression in the perirhinal and prefrontal cortex, and mGluR5 receptor expression was decreased 14 days after discontinuation of meth. This effect was specific to mGluR5 levels in the perirhinal cortex, as no differences were identified in the hippocampus or in mGluR2/3 receptors. These results from a clinically-relevant animal model of addiction suggest that mGluR5 receptor modulation may be a potential treatment of cognitive dysfunction in meth addiction.

  15. A comparison of conformal and intensity-modulated techniques for oesophageal radiotherapy

    Nutting, Christopher M.; Bedford, James L.; Cosgrove, Vivian P.; Tait, Diana M.; Dearnaley, David P.; Webb, Steve

    2001-01-01

    Background and purpose: To investigate the potential of intensity-modulated radiotherapy (IMRT) to reduce lung irradiation in the treatment of oesophageal carcinoma with radical radiotherapy. Materials and methods: A treatment planning study was performed to compare two-phase conformal radiotherapy (CFRT) with IMRT in five patients. The CFRT plans consisted of anterior, posterior and bilateral posterior oblique fields, while the IMRT plans consisted of either nine equispaced fields (9F), or four fields (4F) with orientations equal to the CFRT plans. IMRT plans with seven, five or three equispaced fields were also investigated in one patient. Treatment plans were compared using dose-volume histograms and normal tissue complication probabilities. Results: The 9F IMRT plan was unable to improve on the homogeneity of dose to the planning target volume (PTV), compared with the CFRT plan (dose range, 16.9±4.5 (1 SD) vs. 12.4±3.9%; P=0.06). Similarly, the 9F IMRT plan was unable to reduce the mean lung dose (11.7±3.2 vs. 11.0±2.9 Gy; P=0.2). Similar results were obtained for seven, five and three equispaced fields in the single patient studied. The 4F IMRT plan provided comparable PTV dose homogeneity with the CFRT plan (11.8±3.3 vs. 12.4±3.9%; P=0.6), with reduced mean lung dose (9.5±2.3 vs 11.0±2.9 Gy; P=0.001). Conclusions: IMRT using nine equispaced fields provided no improvement over CFRT. This was because the larger number of fields in the IMRT plan distributed a low dose over the entire lung. In contrast, IMRT using four fields equal to the CFRT fields offered an improvement in lung sparing. Thus, IMRT with a few carefully chosen field directions may lead to a modest reduction in pneumonitis, or allow tumour dose escalation within the currently accepted lung toxicity

  16. In vivo verification of superficial dose for head and neck treatments using intensity-modulated techniques

    Qi Zhenyu; Deng Xiaowu; Huang Shaomin; Zhang Li; He Zhichun; Allen Li, X.; Kwan, Ian; Lerch, Michael; Cutajar, Dean; Metcalfe, Peter; Rosenfeld, Anatoly

    2009-01-01

    Skin dose is one of the key issues for clinical dosimetry in radiation therapy. Currently planning computer systems are unable to accurately predict dose in the buildup region, leaving ambiguity as to the dose levels actually received by the patient's skin during radiotherapy. This is one of the prime reasons why in vivo measurements are necessary to estimate the dose in the buildup region. A newly developed metal-oxide-semiconductor-field-effect-transistor (MOSFET) detector designed specifically for dose measurements in rapidly changing dose gradients was introduced for accurate in vivo skin dosimetry. The feasibility of this detector for skin dose measurements was verified in comparison with plane parallel ionization chamber and radiochromic films. The accuracy of a commercial treatment planning system (TPS) in skin dose calculations for intensity-modulated radiation therapy treatment of nasopharyngeal carcinoma was evaluated using MOSFET detectors in an anthropomorphic phantom as well as on the patients. Results show that this newly developed MOSFET detector can provide a minimal but highly reproducible intrinsic buildup of 7 mg cm -2 corresponding to the requirements of personal surface dose equivalent Hp (0.07). The reproducibility of the MOSFET response, in high sensitivity mode, is found to be better than 2% at the phantom surface for the doses normally delivered to the patients. The MOSFET detector agrees well with the Attix chamber and the EBT Gafchromic registered film in terms of surface and buildup region dose measurements, even for oblique incident beams. While the dose difference between MOSFET measurements and TPS calculations is within measurement uncertainty for the depths equal to or greater than 0.5 cm, an overestimation of up to 8.5% was found for the surface dose calculations in the anthropomorphic phantom study. In vivo skin dose measurements reveal that the dose difference between the MOSFET results and the TPS calculations was on average -7

  17. On-line monitoring of solar cell module production by ellipsometry technique

    Fried, M.

    2014-01-01

    Non-destructive analyzing tools are needed at all stages of thin film photovoltaic (PV) development, and on production lines. In thin film PV, layer thicknesses, micro-structure, composition, layer optical properties, and their uniformity (because each elementary cell is connected electrically in series within a big panel) serve as an important starting point in the evaluation of the performance of the cell or module. An important focus is to express the dielectric functions of each component material in terms of a handful of wavelength independent parameters whose variation can cover all process variants of that material. With the resulting database, spectroscopic ellipsometry coupled with multilayer analysis can be developed for on-line point-by-point mapping and on-line line-by-line imaging. This work tries to review the investigations of different types of PV-layers (anti-reflective coating, transparent-conductive oxide (TCO), multi-diode-structure, absorber and window layers) showing the existing dielectric function databases for the thin film components of CdTe, CuInGaSe 2 , thin Si, and TCO layers. Off-line point-by-point mapping can be effective for characterization of non-uniformities in full scale PV panels in developing labs but it is slow in the on-line mode when only 15 points can be obtained (within 1 min) as a 120 cm long panel moves by the mapping station. In the last years [M. Fried et al., Thin Solid Films 519, 2730 (2011)], instrumentation was developed that provides a line image of spectroscopic ellipsometry (wl = 350–1000 nm) data. Up to now a single 30 point line image can be collected in 10 s over a 15 cm width of PV material. This year we are building a 30 and a 60 cm width expanded beam ellipsometer the speed of which will be increased by 10 ×. Then 1800 points can be mapped in a 1 min traverse of a 60 ∗ 120 cm PV panel or flexible roll-to-roll substrate. - Highlights: • Instrumentation developed provides a line image of

  18. On-line monitoring of solar cell module production by ellipsometry technique

    Fried, M., E-mail: fried@mfa.kfki.hu

    2014-11-28

    Non-destructive analyzing tools are needed at all stages of thin film photovoltaic (PV) development, and on production lines. In thin film PV, layer thicknesses, micro-structure, composition, layer optical properties, and their uniformity (because each elementary cell is connected electrically in series within a big panel) serve as an important starting point in the evaluation of the performance of the cell or module. An important focus is to express the dielectric functions of each component material in terms of a handful of wavelength independent parameters whose variation can cover all process variants of that material. With the resulting database, spectroscopic ellipsometry coupled with multilayer analysis can be developed for on-line point-by-point mapping and on-line line-by-line imaging. This work tries to review the investigations of different types of PV-layers (anti-reflective coating, transparent-conductive oxide (TCO), multi-diode-structure, absorber and window layers) showing the existing dielectric function databases for the thin film components of CdTe, CuInGaSe{sub 2}, thin Si, and TCO layers. Off-line point-by-point mapping can be effective for characterization of non-uniformities in full scale PV panels in developing labs but it is slow in the on-line mode when only 15 points can be obtained (within 1 min) as a 120 cm long panel moves by the mapping station. In the last years [M. Fried et al., Thin Solid Films 519, 2730 (2011)], instrumentation was developed that provides a line image of spectroscopic ellipsometry (wl = 350–1000 nm) data. Up to now a single 30 point line image can be collected in 10 s over a 15 cm width of PV material. This year we are building a 30 and a 60 cm width expanded beam ellipsometer the speed of which will be increased by 10 ×. Then 1800 points can be mapped in a 1 min traverse of a 60 ∗ 120 cm PV panel or flexible roll-to-roll substrate. - Highlights: • Instrumentation developed provides a line image of

  19. Evaluation of aluminum oxide dosimeters using OSL technique in dosimetry of clinical photon beams on volumetric modulated arc treatment

    Villani, Daniel

    2017-01-01

    Treatment using Volumetric Modulated Arc Radiation Therapy is the most modern modality of conformational radiotherapy so that, with the overlapping of several fields, the dose distributions provide a perfect conformation to the tumor, reducing the probability of complications in adjacent normal tissues. In this sense, many efforts are being invested to improve dose distribution compliance as well as the integration of imaging techniques for tumor screening and correction of inter and intrafraction variations. To this end, an intensive monitoring of the quality of the processes and a quality assurance program are fundamental for patient safety and compliance with current legislation; besides the use of different dosimetry methodologies for intercomparison and validation of the results. The aim of this study is to evaluate and compare the performance of aluminum oxide (Al_2O_3:C) OSL dosimeters manufactured by Landauer Inc. with those produced by Rexon™ in the dosimetry of high energy photon clinical bundles used in Volumetric Modulated Arc Therapy - (VMAT) using different simulating objects. The dosimeters were characterized for gamma radiation of the "6"0Co and for clinical photon beams of 6 MV typical of treatments by VMAT under conditions of electronic equilibrium and maximum dose respectively. Performance tests of the TL and OSL readers used and repeatability of the samples were evaluated. After all tests, the dosimeters were irradiated in the simulation of different radiotherapy treatments by VMAT and their responses compared to the planning system. All types of dosimeters presented satisfactory results in verifying the doses of this type of planning simulation. The Al_2O_3:C dosimeters presented compatible results and validated by the other dosimeters and ionization chamber. Regarding the best technique, the OSL InLight commercial system presents greater practicality and versatility for use and application in the clinical routine. (author)

  20. Comparison of the effects of the GABAB receptor positive modulator BHF177 and the GABAB receptor agonist baclofen on anxiety-like behavior, learning, and memory in mice.

    Li, Xia; Risbrough, Victoria B; Cates-Gatto, Chelsea; Kaczanowska, Katarzyna; Finn, M G; Roberts, Amanda J; Markou, Athina

    2013-07-01

    γ-Aminobutyric acid B (GABAB) receptor activation is a potential therapeutic approach for the treatment of drug addiction, pain, anxiety, and depression. However, full agonists of this receptor induce side-effects, such as sedation, muscle relaxation, tolerance, and cognitive disruption. Positive allosteric modulators (PAMs) of the GABAB receptor may have similar therapeutic effects as agonists with superior side-effect profiles. The present study behaviorally characterized N-([1R,2R,4S]-bicyclo[2.2.1]hept-2-yl)-2-methyl-5-(4-[trifluoromethyl]phenyl)-4-pyrimidinamine (BHF177), a GABAB receptor PAM, in mouse models of anxiety-like behavior, learning and memory. In addition, the effects of BHF177 were compared with the agonist baclofen. Unlike the anxiolytic chlordiazepoxide, baclofen (0.5, 1.5, and 2.5 mg/kg, intraperitoneally) and BHF177 (10, 20, and 40 mg/kg, orally) had no effect on anxiety-like behavior in the elevated plus maze, light/dark box, or Vogel conflict test. Baclofen increased punished drinking in the Vogel conflict test, but this effect may be attributable to the analgesic actions of baclofen. At the highest dose tested (2.5 mg/kg), baclofen-treated mice exhibited sedation-like effects (i.e., reduced locomotor activity) across many of the tests, whereas BHF177-treated mice exhibited no sedation-like effects. BHF177 exhibited pro-convulsion properties only in mice, but not in rats, indicating that this effect may be species-specific. At doses that were not sedative or pro-convulsant, baclofen and BHF177 had no selective effects on fear memory retrieval in contextual and cued fear conditioning or spatial learning and memory in the Barnes maze. These data suggest that BHF177 has little sedative activity, no anxiolytic-like profile, and minimal impairment of learning and memory in mice. Copyright © 2013 Elsevier Ltd. All rights reserved.

  1. Effects of standardized Ginkgo biloba extract on the acquisition, retrieval and extinction of conditioned suppression: Evidence that short-term memory and long-term memory are differentially modulated.

    Zamberlam, C R; Vendrasco, N C; Oliveira, D R; Gaiardo, R B; Cerutti, S M

    2016-10-15

    demonstrated (SR=0.63, Pshort-term memory as verified by data from the within-session extinction (1 to 8-10 trials) during the retention test (SR=0.73 to SR=0.59; Pmemory, which suggests that EGb has anti-anxiety effects. Taken together, the current findings suggest that EGb differentially modulates short- and long-term memory, as well as anxiety-like behavior. The actions of EGb may provide information regarding the beneficial effects in the prevention and treatment of neurocognitive impairments and anxiety disorders. Additional analyses are necessary to facilitate an understanding of these effects; however, previous data from our group suggest that GABAergic, serotoninergic and glutamatergic receptors are potential targets of the effects of EGb on conditioned suppression. Copyright © 2016. Published by Elsevier Inc.

  2. Diagnostic radiography students' perceptions of formative peer assessment within a radiographic technique module

    Elshami, W.; Abdalla, M.E.

    2017-01-01

    Introduction: Assessment is a central part of student learning. Student involvement in peer assessment leads to significant improvement in students' performance, supports students' learning, promotes the development of evaluation skills and encourages reflection. Aim: The aim of this study is to assess perceptions of the Formative Peer Assessment (FPA) initiative within a higher education setting for undergraduate radiography students. Methods: Qualitative action research was conducted. Students were allowed to anonymously assess each other's assignments using a standardized evaluation sheet that they had been trained to use. Participants' perceptions were assessed through focus group discussion. Results: The findings showed that students' experiences with peer assessment were positive. Students acknowledged that they received valuable feedback and learned from assessing their peers. Students recommended the need for training and suggested using more than one evaluator. Conclusion: The FPA initiative in the study institution believed to be succeed as the students had a positive experience with the FPA. Students learnt from PA and from self-assessment. Implementation of PA will promote reflection and critical thinking and problem solving skills, that are important traits in radiography graduate profile as in radiography clinical practice the professional require to modify imaging techniques and critique images to ensure the quality of care. - Highlights: • Participants had a positive experience with the Formative Peer Assessment (FPA). • Students believed that the FPA had a positive impact on their learning. • FPA was time-consuming but benefits outweigh the extra time commitment. • Comprehensive training and detailed grading rubric are recommended to improve FPA.

  3. HDAC Inhibition Modulates Hippocampus-Dependent Long-Term Memory for Object Location in a CBP-Dependent Manner

    Haettig, Jakob; Stefanko, Daniel P.; Multani, Monica L.; Figueroa, Dario X.; McQuown, Susan C.; Wood, Marcelo A.

    2011-01-01

    Transcription of genes required for long-term memory not only involves transcription factors, but also enzymatic protein complexes that modify chromatin structure. Chromatin-modifying enzymes, such as the histone acetyltransferase (HAT) CREB (cyclic-AMP response element binding) binding protein (CBP), are pivotal for the transcriptional regulation…

  4. CRTC1 Nuclear Translocation Following Learning Modulates Memory Strength via Exchange of Chromatin Remodeling Complexes on the Fgf1 Gene.

    Uchida, Shusaku; Teubner, Brett J W; Hevi, Charles; Hara, Kumiko; Kobayashi, Ayumi; Dave, Rutu M; Shintaku, Tatsushi; Jaikhan, Pattaporn; Yamagata, Hirotaka; Suzuki, Takayoshi; Watanabe, Yoshifumi; Zakharenko, Stanislav S; Shumyatsky, Gleb P

    2017-01-10

    Memory is formed by synapse-to-nucleus communication that leads to regulation of gene transcription, but the identity and organizational logic of signaling pathways involved in this communication remain unclear. Here we find that the transcription cofactor CRTC1 is a critical determinant of sustained gene transcription and memory strength in the hippocampus. Following associative learning, synaptically localized CRTC1 is translocated to the nucleus and regulates Fgf1b transcription in an activity-dependent manner. After both weak and strong training, the HDAC3-N-CoR corepressor complex leaves the Fgf1b promoter and a complex involving the translocated CRTC1, phosphorylated CREB, and histone acetyltransferase CBP induces transient transcription. Strong training later substitutes KAT5 for CBP, a process that is dependent on CRTC1, but not on CREB phosphorylation. This in turn leads to long-lasting Fgf1b transcription and memory enhancement. Thus, memory strength relies on activity-dependent changes in chromatin and temporal regulation of gene transcription on specific CREB/CRTC1 gene targets. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

  5. Interactions between Brainstem Noradrenergic Neurons and the Nucleus Accumbens Shell in Modulating Memory for Emotionally Arousing Events

    Kerfoot, Erin C.; Williams, Cedric L.

    2011-01-01

    The nucleus accumbens shell (NAC) receives axons containing dopamine-[beta]-hydroxylase that originate from brainstem neurons in the nucleus of the solitary tract (NTS). Recent findings show that memory enhancement produced by stimulating NTS neurons after learning may involve interactions with the NAC. However, it is unclear whether these…

  6. Intensity modulation in breast radiotherapy: Development of an innovative field-in-field technique at Institut Gustave-Roussy

    Heymann, S.; Bourhis, J.; Bourgier, C.; Verstraet, R.; Pichenot, C.; Vergne, E.; Lefkopoulos, D.; Husson, F.; Kafrouni, H.; Mahe, J.; Kandalaft, B.; Marsiglia, H.

    2011-01-01

    Purpose. - To assess the potential dosimetric gain of pre-segmentation modulated radiotherapy (OAPS, DosiSoft TM ) of breast, compared to routine 3D conformal radiotherapy. Patients and methods. - Twenty patients treated with conservative surgery for breast cancer (9 right and 11 left sided) with various breast volume (median 537 cm 3 ; range [100-1049 cm 3 ]) have been selected. For each patient, we have delineated a breast volume and a compensation volume (target volumes), as well as organs at risk (lungs and heart). Two treatment plans have been generated: one using the routine 3D conformal technique and the other with the pre-segmentation algorithm of DosiSoft TM (OAPS). The dose distribution were analyzed using the conformity index for target volumes, mean dose and V 30 Gy for the heart, and mean dose, V 20 Gy and V 30 Gy for lungs. Results. - Over the 20 patients, the conformity index increased from 0.897 with routine technique to 0.978 with OAPS (P TM ) is an original method of segmentation of breast. It is automatic, fast and easy, and is able to increase the conformity index, while sparing organ at risk. (authors)

  7. SU-F-T-446: Improving Craniospinal Irradiation Technique Using Volumetric Modulated Arc Therapy (VMAT) Planning and Its Dosimetric Verification

    Yang, X; Tejani, M; Jiang, X; Elder, E; Dhabaan, A [Emory University, Atlanta, GA (United States)

    2016-06-15

    Purpose: The purpose of this study is to investigate a volumetric modulated arc therapy (VMAT) treatment planning technique for supine craniospinal irradiation (CSI). Evaluate the suitability of VMAT for CSI with dosimetric measurements and compare it to 3D conformal planning using specific plan metrics such as dose conformity, homogeneity, and dose of organs at risk (OAR). Methods: Ten CSI patients treated with conventional 3D technique were re-planned with VMAT. The PTV was contoured to include the whole contents of the brain and spinal canal with a uniform margin of 5 mm. VMAT plans were generated with two partial arcs covering the brain, two partial arcs for the superior portion of the spinal cord and two partial arcs covering the remaining inferior portion of the spinal cord. Conformity index (CI), heterogeneity indexes (HI) and max and mean doses of OAR were compared to 3D plans. VMAT plans were delivered onto an anthropomorphic phantom loaded with Gafchromic films and OSLDs placed at specific positions to evaluate the plan dose at the junctions and as well as the plan dose distributions. Results: This VMAT technique was validated with a clinical study of 10 patients. The average CI was 1.03±0.02 for VMAT plans and 1.96±0.32 for conformal plans. And the average HI was 1.15±0.01 for VMAT plans and 1.51±0.21 for conformal plans. The mean and max doses to the all OARs for VMAT plans were significantly lower than conformal plans. The measured dose in phantom for VAMT plans was comparable to the calculated dose in Eclipse and the doses at junctions were verified. Conclusion: VMAT CSI was able to achieve better dose conformity and heterogeneity as well as significantly reducing the dose to Heart, esophagus and larynx. VMAT CSI appears to be a dosimterically advantageous, faster delivery, has better reproducibility CSI treatment.

  8. NUMA obliviousness through memory mapping

    M.M. Gawade (Mrunal); M.L. Kersten (Martin)

    2015-01-01

    htmlabstractWith the rise of multi-socket multi-core CPUs a lot of effort is being put into how to best exploit their abundant CPU power. In a shared memory setting the multi-socket CPUs are equipped with their own memory module, and access memory modules across sockets in a non-uniform

  9. NUMA obliviousness through memory mapping

    Gawade, M.; Kersten, M.; Pandis, I.; Kersten, M.

    2015-01-01

    With the rise of multi-socket multi-core CPUs a lot of effort is being put into how to best exploit their abundant CPU power. In a shared memory setting the multi-socket CPUs are equipped with their own memory module, and access memory modules across sockets in a non-uniform access pattern (NUMA).

  10. Fabrication and evaluation of pH-modulated solid dispersion for telmisartan by spray-drying technique.

    Marasini, Nirmal; Tran, Tuan Hiep; Poudel, Bijay Kumar; Cho, Hyuk Jun; Choi, Young Keun; Chi, Sang-Cheol; Choi, Han-Gon; Yong, Chul Soon; Kim, Jong Oh

    2013-01-30

    The present study was undertaken to overcome the problems associated with solubility, dissolution and oral bioavailability of a poorly water-soluble ionizable drug, telmisartan (TMS). For these purposes, a solubility test was carried to select the appropriate formulation composition from various carriers and alkalizers. Solid dispersions (SDs) of TMS were prepared at different drug-to-carrier ratios by the spray-drying technique, and were characterized by dissolution and aqueous solubility studies. The optimum formulation was investigated by dissolution studies at different pH and water media and its solid state characterisations were performed by scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and X-ray diffraction (XRD) studies. In solubility and dissolution tests, all TMS-loaded pH-modulated SDs (pH(M)-SDs) exhibited marked improvement in the dissolution behavior when compared with crystalline TMS powder. The optimum formulation of pH(M)-SD consisted of TMS/PVP (polyvinylpyrrolidone) K30/Na(2)CO(3) at a weight ratio of 2/0.5/3 and showed significant improvement in the aqueous solubility and dissolution rate by approximately 40,000- and 3-fold, respectively, compared to TMS powder. Solid-state characterization revealed the changed in crystallinity of TMS into amorphous state. Furthermore, area under the drug concentration time-curve (AUC) of TMS from the pH(M)-SD increased by 13.4- and 2.1-fold, compared with TMS powder and commercial product, respectively. According to these observations, taken together with dissolution and pharmacokinetic behaviors, pH-modulated SD in the presence of an alkalizer for a poorly water-soluble ionizable drug, TMS, appeared to be efficacious for enhancing its bioavailability. Copyright © 2012 Elsevier B.V. All rights reserved.

  11. 75 FR 14467 - In the Matter of: Certain Dynamic Random Access Memory Semiconductors and Products Containing...

    2010-03-25

    ... Access Memory Semiconductors and Products Containing Same, Including Memory Modules; Notice of... semiconductors and products containing same, including memory modules, by reason of infringement of certain... importation of certain dynamic random access memory semiconductors or products containing the same, including...

  12. Comparison radiation dose of Z-axis automatic tube current modulation technique with fixed tube current multi-detector row CT scanning of lower extremity venography

    Yoo, Beong Gyu; Kweon, Dae Cheol; Lee, Jong Seok; Jang, Keun Jo; Jeon, Sang Hwan; Kim, Yong Soo

    2007-01-01

    Z-axis automatic tube current modulation technique automatically adjusts tube current based on size of body region scanned. The purpose of the current study was to compare noise, and radiation dose of Multi-Detector row CT (MDCT) of lower extremity performed with Z-axis modulation technique of automatic tube current modulation with manual selection fixed tube current. Fifty consecutive underwent MDCT venography of lower extremity with use of a MDCT scanner fixed tube current and Z-axis automatic tube current modulation technique (10, 11 and 12 HU noise index, 70∼450 mA). Scanning parameters included 120 kVp, 0.5 second gantry rotation time, 1.35:1 beam pitch, and 1 mm reconstructed section thickness. For each subject, images obtained with Z-axis modulation were compared with previous images obtained with fixed tube current (200, 250, 300 mA) and with other parameters identical. Images were compared for noise at five levels: iliac, femoral, popliteal, tibial, and peroneal vein of lower extremity. Tube current and gantry rotation time used for acquisitions at these levels were recorded. All CT examinations of study and control groups were diagnostically acceptable, though objective noise was significantly more with Z-axis automatic tube current modulation. Compared with fixed tube current, Z-axis modulation resulted in reduction of CTDIvol (range, -6.5%∼-35.6%) and DLP (range,-0.2%∼-20.2%). Compared with manually selected fixed tube current, Z-axis automatic tube current modulation resulted in reduced radiation dose at MDCT of lower extremity venography

  13. Internal filament modulation in low-dielectric gap design for built-in selector-less resistive switching memory application

    Chen, Ying-Chen; Lin, Chih-Yang; Huang, Hui-Chun; Kim, Sungjun; Fowler, Burt; Chang, Yao-Feng; Wu, Xiaohan; Xu, Gaobo; Chang, Ting-Chang; Lee, Jack C.

    2018-02-01

    Sneak path current is a severe hindrance for the application of high-density resistive random-access memory (RRAM) array designs. In this work, we demonstrate nonlinear (NL) resistive switching characteristics of a HfO x /SiO x -based stacking structure as a realization for selector-less RRAM devices. The NL characteristic was obtained and designed by optimizing the internal filament location with a low effective dielectric constant in the HfO x /SiO x structure. The stacking HfO x /SiO x -based RRAM device as the one-resistor-only memory cell is applicable without needing an additional selector device to solve the sneak path issue with a switching voltage of ~1 V, which is desirable for low-power operating in built-in nonlinearity crossbar array configurations.

  14. Early Auditory Evoked Potential Is Modulated by Selective Attention and Related to Individual Differences in Visual Working Memory Capacity

    Giuliano, Ryan J.; Karns, Christina M.; Neville, Helen J.; Hillyard, Steven A.

    2014-01-01

    A growing body of research suggests that the predictive power of working memory (WM) capacity for measures of intellectual aptitude is due to the ability to control attention and select relevant information. Crucially, attentional mechanisms implicated in controlling access to WM are assumed to be domain-general, yet reports of enhanced attentional abilities in individuals with larger WM capacities are primarily within the visual domain. Here, we directly test the link between WM capacity and...

  15. Guarana (Paullinia cupana) ameliorates memory impairment and modulates acetylcholinesterase activity in Poloxamer-407-induced hyperlipidemia in rat brain.

    Ruchel, Jader B; Braun, Josiane B S; Adefegha, Stephen A; Guedes Manzoni, Alessandra; Abdalla, Fátima H; de Oliveira, Juliana S; Trelles, Kelly; Signor, Cristiane; Lopes, Sônia T A; da Silva, Cássia B; Castilhos, Lívia G; Rubin, Maribel A; Leal, Daniela B R

    2017-01-01

    Hyperlipidemia is a risk factor for the development of cognitive dysfunction and atherosclerosis. Natural compounds have recently received special attention in relation to the treatment of disease due to their low cost and wide margin of safety. Thus, the aim of this study was to determine the possible preventive effect of guarana powder (Paullinia cupana) on memory impairment and acetylcholinesterase (AChE) activity in the brain structures of rats with Poloxamer-407-induced hyperlipidemia. Adult male Wistar rats were pretreated with guarana (12.5, 25 and 50mg/kg/day) and caffeine (0.2mg/kg/day) by gavage for a period of 30days. Simvastatin (0.04mg/kg) was administered as a comparative standard. Acute hyperlipidemia was induced with intraperitoneal injections of 500mg/kg of Poloxamer-407. Memory tests and evaluations of anxiety were performed. The cortex, cerebellum, hippocampus, hypothalamus and striatum were separated to assess acetylcholinesterase activity. Our results revealed that guarana powder was able to reduce the levels of TC and LDL-C in a manner similar to simvastatin. Guarana powder also partially reduced the liver damage caused by hyperlipidemia. Guarana was able to prevent changes in the activity of AChE and improve memory impairment due to hyperlipidemia. Guarana powder may therefore be a source of promising phytochemicals that can be used as adjuvant therapy in the management of hyperlipidemia and cognitive disorders. Copyright © 2016 Elsevier Inc. All rights reserved.

  16. SU-F-T-85: Energy Modulated Electron Postmastectomy Unreconstructed (PU) Chest Wall (CW) Irradiation Technique to Achieve Heart Sparing

    Hong, L; Ballangrud, A; Mechalakos, J [Memorial Sloan-Kettering Cancer Center, New York, NY (United States); McCormick, B [Memerial Sloan-Kettering Cancer Center, New York, NY (United States)

    2016-06-15

    Purpose: For left-sided PU patients requiring CW and nodal irradiation, sometimes partial wide tangents (PWT) are not feasible due to abnormal chest wall contour or heart position close to the anterior chest wall or unusual wide excision scar. We developed an energy modulated electron chest wall irradiation technique that will achieve heart sparing. Methods: Ten left-sided PU patients were selected for this dosimetry study. If PWT were used, the amount of the ipsilateral lung would be ranged 3.4 to 4.4 cm, and the amount of heart would be ranged 1.3 to 3.8 cm. We used electron paired fields that matched on the skin to achieve dose conformity to the chest wall. The enface electron fields were designed at extended SSD from a single isocenter and gantry angle with different energy beams using different cutout. Lower energy was used in the central chest wall part and higher energy was used in the periphery of the chest wall. Bolus was used for the electron fields to ensure adequate skin dose coverage. The electron fields were matched to the photon supra-clavicle field in the superior region. Daily field junctions were used to feather the match lines between all the fields. Target volumes and normal tissues were drawn according to institutional protocols. Prescription dose was 2Gy per fraction for a total 50Gy. Dose calculations were done with Eclipse EMC-11031 for Electron and AAA-11031 for photons. Results: Six patients were planned using 6/9MeV, three using 9/12MeV and one 6/12MeV. Target volumes achieved adequate coverage. For heart, V30Gy, V20Gy and Mean Dose were 0.6%±0.6%, 2.7%±1.7%, and 3.0Gy±0.8Gy respectively. For ipsilateral lung, V50Gy, V20Gy, V10Gy and V5Gy were 0.9%±1.1%, 34.3%±5.1%, 51.6%±6.3% and 64.1%±7.5% respectively. Conclusion: For left-sided PU patients with unusual anatomy, energy modulated electron CW irradiation technique can achieve heart sparing with acceptable lung dose.

  17. Period1 gates the circadian modulation of memory-relevant signaling in mouse hippocampus by regulating the nuclear shuttling of the CREB kinase pP90RSK

    Rawashdeh, Oliver; Jilg, Antje; Maronde, Erik

    2016-01-01

    , the presence of PER1 in hippocampal neurons is a prerequisite for the time-of-day-dependent phosphorylation of CREB, as it regulates the shuttling of pP90RSK into the nucleus. Representative immunofluorescence images show a temporal difference in phosphorylated cAMP response element-binding protein (p...... activation. Taken together, the PER1-dependent modulation of cytoplasmic-to-nuclear signaling in the murine hippocampus provides a molecular explanation for how the circadian system potentially shapes a temporal framework for daytime-dependent memory performance, and adds a novel facet to the versatility......CREB; green color) levels in all regions of the dorsal hippocampus between a wild-type C3H mouse (WT; left) and a Period1-knockout (Per1−/−; right) mouse. Images were taken 2 h after lights on, thus, when fluctuating levels of pCREB peak in WT mouse hippocampus. Insets show a representative hippocampal neuron...

  18. Dosimetric study of volumetric arc modulation with RapidArc and intensity-modulated radiotherapy in patients with cervical cancer and comparison with 3-dimensional conformal technique for definitive radiotherapy in patients with cervical cancer

    Guy, Jean-Baptiste [Department of Radiation Oncology, Institut de Cancérologie de la Loire Lucien Neuwirth, Saint-Priest en Jarez (France); Falk, Alexander T. [Department of Radiation Oncology, Centre Antoine Lacassagne, Nice (France); Auberdiac, Pierre [Department of Radiation Oncology, Clinique Claude Bernard, Albi (France); Cartier, Lysian; Vallard, Alexis [Department of Radiation Oncology, Institut de Cancérologie de la Loire Lucien Neuwirth, Saint-Priest en Jarez (France); Ollier, Edouard [Department of Pharmacology-Toxicology, Centre Hospitalier Universitaire de Saint-Etienne, Saint-Priest en Jarez (France); Trone, Jane-Chloé; Khodri, Moustapha [Department of Radiation Oncology, Institut de Cancérologie de la Loire Lucien Neuwirth, Saint-Priest en Jarez (France); Chargari, Cyrus [Department of Radiation Oncology, Hôpital d’instruction de Armées du Val-de-Grâce, Paris (France); Magné, Nicolas, E-mail: nicolas.magne@icloire.fr [Department of Radiation Oncology, Institut de Cancérologie de la Loire Lucien Neuwirth, Saint-Priest en Jarez (France)

    2016-04-01

    Introduction: For patients with cervical cancer, intensity-modulated radiation therapy (IMRT) improves target coverage and allows dose escalation while reducing the radiation dose to organs at risk (OARs). In this study, we compared dosimetric parameters among 3-dimensional conformal radiotherapy (3D-CRT), “step-and-shoot” IMRT, and volumetric intensity-modulated arc radiotherapy (VMAT) in a series of patients with cervical cancer receiving definitive radiotherapy. Computed tomography (CT) scans of 10 patients with histologically proven cervical cancer treated with definitive radiation therapy (RT) from December 2008 to March 2010 at our department were selected for this study. The gross tumor volume (GTV) and clinical target volume (CTV) were delineated following the guidelines of the Gyn IMRT consortium that included cervix, uterus, parametrial tissues, and the pelvic nodes including presacral. The median age was 57 years (range: 30 to 85 years). All 10 patients had squamous cell carcinoma with Federation of Gynecology and Obstetrics (FIGO) stage IB-IIIB. All patients were treated by VMAT. OAR doses were significantly reduced for plans with intensity-modulated technique compared with 3D-CRT except for the dose to the vagina. Between the 2 intensity-modulated techniques, significant difference was observed for the mean dose to the small intestine, to the benefit of VMAT (p < 0.001). There was no improvement in terms of OARs sparing for VMAT although there was a tendency for a slightly decreased average dose to the rectum: − 0.65 Gy but not significant (p = 0.07). The intensity modulation techniques have many advantages in terms of quality indexes, and particularly OAR sparing, compared with 3D-CRT. Following the ongoing technologic developments in modern radiotherapy, it is essential to evaluate the intensity-modulated techniques on prospective studies of a larger scale.

  19. Repeated Neck Restraint Stress Bidirectionally Modulates Excitatory Transmission in the Dentate Gyrus and Performance in a Hippocampus-dependent Memory Task.

    Spyrka, Jadwiga; Hess, Grzegorz

    2018-05-21

    The consequences of stress depend on characteristics of the stressor, including the duration of exposure, severity, and predictability. Exposure of mice to repeated neck restraint has been shown to bidirectionally modulate the potential for long-term potentiation (LTP) in the dentate gyrus (DG) in a manner dependent on the number of restraint repetitions, but the influence of repeated brief neck restraint on electrophysiology of single DG neurons has not yet been investigated. Here, we aimed at finding the effects of 1, 3, 7, 14, or 21 daily neck restraint sessions lasting 10 min on electrophysiological characteristics of DG granule cells as well as excitatory and inhibitory synaptic inputs to these neurons. While the excitability of DG granule cells and inhibitory synaptic transmission were unchanged, neck restraint decreased the frequency of spontaneous excitatory currents after three repetitions but enhanced it after 14 and 21 repetitions. The consequences of repeated neck restraint on hippocampus-dependent memory were investigated using the object location test (OLT). Neck restraint stress impaired cognitive performance in the OLT after three repetitions but improved it after 14 and 21 repetitions. Mice subjected to three neck restraint sessions displayed an increase in the measures of depressive and anxiety-like behaviors, however, prolongation of the exposure to neck restraint resulted in a gradual decline in the intensity of these measures. These data indicate that stress imposed by an increasing number of repeated neck restraint episodes bidirectionally modulates both excitatory synaptic transmission in the DG and cognitive performance in the object location memory task. Copyright © 2018 IBRO. Published by Elsevier Ltd. All rights reserved.

  20. Tangential Volumetric Modulated Radiotherapy - A New Technique for Large Scalp Lesions with a Case Study in Lentigo Maligna

    E. Daniel Santos

    2015-06-01

    Full Text Available Introduction: Dose homogeneity within and dose conformity to the target volume can be a challenge to achieve when treating large area scalp lesions. Traditionally High Dose Rate (HDR brachytherapy (BT scalp moulds have been considered the ultimate conformal therapy. We have developed a new technique, Tangential Volumetric Modulated Arc Therapy (TVMAT that treats with the beam tangential to the surface of the scalp. In the TVMAT plan the collimating jaws protect dose-sensitive tissue in close proximity to the planning target volume (PTV. Not all the PTV is within the beam aperture as defined by the jaws during all the beam-on time. We report the successful treatment of one patient. Methods: A patient with biopsy proven extensive lentigo maligna on the scalp was simulated and three plans were created; one using a HDR brachytherapy surface mould, another using a conventional VMAT technique and a third using our new TVMAT technique. The patient was prescribed 55 Gy in 25 fractions. Plans were optimised so that PTV V100% = 100%. Plans were compared using Dose-Value Histogram (DVH analysis, and homogeneity and conformity indices. Results: BT, VMAT and TVMAT PTV median coverage was 105.51%, 103.46% and 103.62%, with homogeneity index of 0.33, 0.07 and 0.07 and the conformity index of 0.30, 0.69 and 0.83 respectively. The median dose to the left hippocampus was 11.8 Gy, 9.0 Gy and 0.6 Gy and the median dose to the right hippocampus was 12.6 Gy, 9.4 Gy and 0.7 Gy for the BT, VMAT and TVMAT respectively. Overall TVMAT delivered the least doses to the surrounding organs, BT delivered the highest. Conclusions: TVMAT was superior to VMAT which was in turn superior to BT in PTV coverage, conformity and homogeneity and delivery of dose to the surrounding organs at risk. The patient was successfully treated to full dose with TVMAT. TVMAT was verified as being the best amongst the three techniques in a second patient.