Discrete Serotonin Systems Mediate Memory Enhancement and Escape Latencies after Unpredicted Aversive Experience in Drosophila Place Memory

PubMed Central

Sitaraman, Divya; Kramer, Elizabeth F.; Kahsai, Lily; Ostrowski, Daniela; Zars, Troy

2017-01-01

Feedback mechanisms in operant learning are critical for animals to increase reward or reduce punishment. However, not all conditions have a behavior that can readily resolve an event. Animals must then try out different behaviors to better their situation through outcome learning. This form of learning allows for novel solutions and with positive experience can lead to unexpected behavioral routines. Learned helplessness, as a type of outcome learning, manifests in part as increases in escape latency in the face of repeated unpredicted shocks. Little is known about the mechanisms of outcome learning. When fruit fly Drosophila melanogaster are exposed to unpredicted high temperatures in a place learning paradigm, flies both increase escape latencies and have a higher memory when given control of a place/temperature contingency. Here we describe discrete serotonin neuronal circuits that mediate aversive reinforcement, escape latencies, and memory levels after place learning in the presence and absence of unexpected aversive events. The results show that two features of learned helplessness depend on the same modulatory system as aversive reinforcement. Moreover, changes in aversive reinforcement and escape latency depend on local neural circuit modulation, while memory enhancement requires larger modulation of multiple behavioral control circuits. PMID:29321732

Determining the relationship between sleep architecture, seizure variables and memory in patients with focal epilepsy.

PubMed

Miller, Laurie A; Ricci, Monica; van Schalkwijk, Frank J; Mohamed, Armin; van der Werf, Ysbrand D

2016-06-01

Sleep has been shown to be important to memory. Both sleep and memory have been found to be abnormal in patients with epilepsy. In this study, we explored the effects that nocturnal epileptiform discharges and the presence of a hippocampal lesion have on sleep patterns and memory. Twenty-five patients with focal epilepsy who underwent a 24-hr ambulatory EEG also completed the Everyday Memory Questionnaire (EMQ). The EEG record was scored for length of time spent in the various sleep stages, time spent awake after sleep onset, and rapid eye movement (REM) latency. Of these sleep variables, only REM latency differed when the epilepsy patients were divided on the bases of either presence/absence of nocturnal discharges or presence/absence of a hippocampal lesion. In both cases, presence of the abnormality was associated with longer latency. Furthermore, longer REM latency was found to be a better predictor of EMQ score than either number of discharges or presence of a hippocampal lesion. Longer REM latency was associated with a smaller percentage of time spent in slow-wave sleep in the early part of the night and may serve as a particularly sensitive marker to disturbances in sleep architecture. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Precision Quantum Control and Error-Suppressing Quantum Firmware for Robust Quantum Computing

DTIC Science & Technology

2014-09-24

Biercuk, Lorenza Viola. Long-time Low - latency Quantum Memory by Dynamical Decoupling, arXiv:1206.6087v1 (06 2012) L. Viola, G. A. Paz-Silva . A...International Patent Application (PCT/AU2013/000649) D. Hayes, K. Khodjasteh L. Viola, M.J. Biercuk, “Long-time low - latency quantum memory by dynamical...Khodjasteh L. Viola, M.J. Biercuk, University of Sydney A28 Physics Road Sydney NS 2006 Long-time low - latency quantum membory by dynamical decoupling

Normal aging affects movement execution but not visual motion working memory and decision-making delay during cue-dependent memory-based smooth-pursuit.

PubMed

Fukushima, Kikuro; Barnes, Graham R; Ito, Norie; Olley, Peter M; Warabi, Tateo

2014-07-01

Aging affects virtually all functions including sensory/motor and cognitive activities. While retinal image motion is the primary input for smooth-pursuit, its efficiency/accuracy depends on cognitive processes. Elderly subjects exhibit gain decrease during initial and steady-state pursuit, but reports on latencies are conflicting. Using a cue-dependent memory-based smooth-pursuit task, we identified important extra-retinal mechanisms for initial pursuit in young adults including cue information priming and extra-retinal drive components (Ito et al. in Exp Brain Res 229:23-35, 2013). We examined aging effects on parameters for smooth-pursuit using the same tasks. Elderly subjects were tested during three task conditions as previously described: memory-based pursuit, simple ramp-pursuit just to follow motion of a single spot, and popping-out of the correct spot during memory-based pursuit to enhance retinal image motion. Simple ramp-pursuit was used as a task that did not require visual motion working memory. To clarify aging effects, we then compared the results with the previous young subject data. During memory-based pursuit, elderly subjects exhibited normal working memory of cue information. Most movement-parameters including pursuit latencies differed significantly between memory-based pursuit and simple ramp-pursuit and also between young and elderly subjects. Popping-out of the correct spot motion was ineffective for enhancing initial pursuit in elderly subjects. However, the latency difference between memory-based pursuit and simple ramp-pursuit in individual subjects, which includes decision-making delay in the memory task, was similar between the two groups. Our results suggest that smooth-pursuit latencies depend on task conditions and that, although the extra-retinal mechanisms were functional for initial pursuit in elderly subjects, they were less effective.

The effect of a novel pentadecapeptide BPC 157 on development of tolerance and physical dependence following repeated administration of diazepam.

PubMed

Jelovac, N; Sikiric, P; Rucman, R; Petek, M; Perovic, D; Marovic, A; Anic, T; Seiwerth, S; Mise, S; Pigac, B; Duplancie, B; Turkovic, B; Dodig, G; Prkacin, I; Stancic-Rokotov, D; Zoricic, I; Aralica, G; Sebecic, B; Ziger, T; Slobodnjak, Z

1999-09-30

A novel gastric pentadecapeptide BPC 157 with different beneficial activities and anticonvulsant effect interacting with GABAergic system could improve diazepam efficacy coadministered (10 microg/kg, 10 ng/kg i.p.) with diazepam (5.0 mg/kg i.p.) twice daily for 10 days, since diazepam chronic medication would otherwise predispose for diazepam- tolerance/withdrawal development (shorter latency to convulsion after convulsant). In diazepam chronically treated mice, it attenuated diazepam tolerance (provoked by later acute administration of diazepam together with convulsant) and postponed physical dependence/withdrawal effects (provoked by later administration of isoniazid). In tolerance assay, at 42 h after the end of conditioning regimen, shorter preconvulsive latencies than in healthy (non-diazepam conditioned) mice following isoniazid (800 mg/kg i.p.) (as hallmark of tolerance) were observed if diazepam (5.0 mg/kg i.p.) was again given acutely to mice previously conditioned with diazepam alone (use of picrotoxin 3.0 mg/kg i.p., as convulsant, with acute application of diazepam in previously diazepam conditioned mice did not lead to tolerance hallmark). This was completely avoided in diazepam+BPC 157 10 microg or diazepam+BPC 157 10 ng chronically treated animals. In physical dependence assay (isoniazid challenge assessed at 6, 14, 42 and 72 h after conditioning medication), when compared to diazepam non-conditioned healthy mice, in diazepam conditioned mice residual anticonvulsive activity was not present already at the earliest post-conditioning interval (i.e., not different latency to isoniazid-convulsions), whereas shorter preconvulsive latencies (as physical dependence/withdrawal hallmark) were noted in diazepam conditioned mice following isoniazid challenge at 42 h and at 72 h after end of conditioning treatment. In diazepam+BPC 157 10 microg- conditioned mice, a residual anticonvulsive activity (i.e., longer latency to isoniazid convulsion) was noted at 6 h post-conditioning, whereas shorter preconvulsive latencies appeared only at 72 h-post-conditioning period. In conclusion, taken together these data (lack of tolerance development (tolerance studies), prolonged residual anticonvulsive activity, and postponed physical dependence/withdrawal hallmark in diazepam+BPC 157 chronically treated mice) with common benzodiazepines tolerance/withdrawal knowledge, it could be speculated that BPC 157 acts favoring the natural homeostasis of the GABA receptor complex as well as enhancing the GABAergic transmission, and having a mechanism at least partly different from those involved in diazepam tolerance/withdrawal, it may be likely used in further therapy of diazepam tolerance and withdrawal.

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

Perumalla, Kalyan S.; Yoginath, Srikanth B.

Problems such as fault tolerance and scalable synchronization can be efficiently solved using reversibility of applications. Making applications reversible by relying on computation rather than on memory is ideal for large scale parallel computing, especially for the next generation of supercomputers in which memory is expensive in terms of latency, energy, and price. In this direction, a case study is presented here in reversing a computational core, namely, Basic Linear Algebra Subprograms, which is widely used in scientific applications. A new Reversible BLAS (RBLAS) library interface has been designed, and a prototype has been implemented with two modes: (1) amore » memory-mode in which reversibility is obtained by checkpointing to memory in forward and restoring from memory in reverse, and (2) a computational-mode in which nothing is saved in the forward, but restoration is done entirely via inverse computation in reverse. The article is focused on detailed performance benchmarking to evaluate the runtime dynamics and performance effects, comparing reversible computation with checkpointing on both traditional CPU platforms and recent GPU accelerator platforms. For BLAS Level-1 subprograms, data indicates over an order of magnitude better speed of reversible computation compared to checkpointing. For BLAS Level-2 and Level-3, a more complex tradeoff is observed between reversible computation and checkpointing, depending on computational and memory complexities of the subprograms.« less

Low latency and persistent data storage

DOEpatents

Fitch, Blake G; Franceschini, Michele M; Jagmohan, Ashish; Takken, Todd E

2014-02-18

Persistent data storage is provided by a method that includes receiving a low latency store command that includes write data. The write data is written to a first memory device that is implemented by a nonvolatile solid-state memory technology characterized by a first access speed. It is acknowledged that the write data has been successfully written to the first memory device. The write data is written to a second memory device that is implemented by a volatile memory technology. At least a portion of the data in the first memory device is written to a third memory device when a predetermined amount of data has been accumulated in the first memory device. The third memory device is implemented by a nonvolatile solid-state memory technology characterized by a second access speed that is slower than the first access speed.

Nimodipine-induced hypotension but not nitroglycerin-induced hypotension preserves long- and short-term memory in adult mice.

PubMed

Haile, Michael; Galoyan, Samuel; Li, Yong-Sheng; Cohen, Barry H; Quartermain, David; Blanck, Thomas; Bekker, Alex

2012-05-01

Acute hypotension may be implicated in cognitive dysfunction. L-type calcium channel blockers in the setting of hypoxia are protective of learning and memory. We tested the hypothesis that hypotension induced by nimodipine (NIMO) and nicardipine (NICA) would be protective of long- and short-term memory compared to hypotension induced by nitroglycerin (NTG). Forty Swiss-Webster mice (30 to 35 g, 6 to 8 weeks) were randomized into 4 groups for i.p. injection immediately after passive avoidance (PA) learning on day 0: (1) NTG (30 mg/kg); (2) NICA (40 mg/kg); (3) NIMO (40 mg/kg); and (4) saline. PA training latencies (seconds) were recorded for entry from a suspended platform into a Plexiglas tube where a shock (0.3 mA; 2-second duration) was automatically delivered. On day 2 latencies were recorded during a testing trial during which no shock was delivered. Latencies >900 seconds were assigned this value. Lower testing latency is indicative of an impairment of long-term associative memory. Forty-nine additional mice were randomized into similar groups for object recognition testing (ORT) and given i.p. injections on day 0. ORT measures short-term memory by exploiting the tendency of mice to prefer novel objects where a familiar object is present. On day 5 during training, 2 identical objects were placed in a circular arena and mice explored both for 15 minutes. A testing trial was conducted 1 hour later for 3 minutes after a novel object replaced a familiar one. Mice with intact memory spend about 65% of the time exploring the novel object. Mice with impaired memory devote equal time to each object. Recognition index (RI) is defined as the ratio of time spent exploring the novel object to time spent exploring both objects was the measure of memory. Mean arterial blood pressure (MAP), cerebral bloodflow, and body and brain oxygenation (PO(2)) studies were done in separate groups of mice to determine the dosages for matched degrees of hypotension and the physiological profile of each treatment. The median PA latencies for the different conditions were as follows: NTG (219.5 ± 93.5 second semi-interquartile range [SIQR]), NICA (372.5 ± 75.5 second SIQR), NIMO (540 ± 200 second SIQR) and saline (804 ± 257.5 second SIQR). Rank methods were used to analyze the PA latencies for significant differences. NTG latency was significantly shorter than NIMO latency (P = 0.012) and saline latency (P = 0.006), but not NICA latency (P = 0.126). ORT RI values showed a similar pattern. We found that NTG RI (47.2 ± 5.9% SEM) was different from NIMO RI (60.2 ± 4.6% SEM, P = 0.031) and different from saline RI (66.9 + 3.7% SEM, P = 0.006). Physiological experiments showed that MAP decreased to 45 to 50 mm Hg in all animals who became minimally responsive to external stimuli within 10 to 15 minutes of injection. Intergroup differences for MAP, body and brain oxygenation, and cerebral bloodflow were not statistically significant. Acute hypotension induced by NIMO was protective of 2 categories of memory formation relevant to the clinical posttreatment period. Both immediate long-term associative memory consolidation as measured by the PA learning paradigm and delayed short-term working memory function as measured by the ORT paradigm were significantly improved compared to matched levels of hypotension induced by NTG. These results indicate the utility of further investigation of l-type calcium channel blockers as a potential means of preserving cognition in the setting of hypotensive and low flow states.

Low latency and persistent data storage

DOEpatents

Fitch, Blake G; Franceschini, Michele M; Jagmohan, Ashish; Takken, Todd

2014-11-04

Persistent data storage is provided by a computer program product that includes computer program code configured for receiving a low latency store command that includes write data. The write data is written to a first memory device that is implemented by a nonvolatile solid-state memory technology characterized by a first access speed. It is acknowledged that the write data has been successfully written to the first memory device. The write data is written to a second memory device that is implemented by a volatile memory technology. At least a portion of the data in the first memory device is written to a third memory device when a predetermined amount of data has been accumulated in the first memory device. The third memory device is implemented by a nonvolatile solid-state memory technology characterized by a second access speed that is slower than the first access speed.

Emotional organization of autobiographical memory.

PubMed

Schulkind, Matthew D; Woldorf, Gillian M

2005-09-01

The emotional organization of autobiographical memory was examined by determining whether emotional cues would influence autobiographical retrieval in younger and older adults. Unfamiliar musical cues that represented orthogonal combinations of positive and negative valence and high and low arousal were used. Whereas cue valence influenced the valence of the retrieved memories, cue arousal did not affect arousal ratings. However, high-arousal cues were associated with reduced response latencies. A significant bias to report positive memories was observed, especially for the older adults, but neither the distribution of memories across the life span nor response latencies varied across memories differing in valence or arousal. These data indicate that emotional information can serve as effective cues for autobiographical memories and that autobiographical memories are organized in terms of emotional valence but not emotional arousal. Thus, current theories of autobiographical memory must be expanded to include emotional valence as a primary dimension of organization.

Effect of harmane, an endogenous β-carboline, on learning and memory in rats.

PubMed

Celikyurt, Ipek Komsuoglu; Utkan, Tijen; Gocmez, Semil Selcen; Hudson, Alan; Aricioglu, Feyza

2013-01-01

Our aim was to investigate the effects of acute harmane administration upon learning and memory performance of rats using the three-panel runway paradigm and passive avoidance test. Male rats received harmane (2.5, 5, and 7.5mg/kg, i.p.) or saline 30 min. before each session of experiments. In the three panel runway paradigm, harmane did not affect the number of errors and latency in reference memory. The effect of harmane on the errors of working memory was significantly higher following the doses of 5mg/kg and 7.5mg/kg. The latency was changed significantly at only 7.5mg/kg in comparison to control group. Animals were given pre-training injection of harmane in the passive avoidance test in order to determine the learning function. Harmane treatment decreased the retention latency significantly and dose dependently, which indicates an impairment in learning. In this study, harmane impaired working memory in three panel runway test and learning in passive avoidance test. As an endogenous bioactive molecule, harmane might have a critical role in the modulation of learning and memory functions. Copyright © 2012 Elsevier Inc. All rights reserved.

Towards reversible basic linear algebra subprograms: A performance study

DOE PAGES

Perumalla, Kalyan S.; Yoginath, Srikanth B.

2014-12-06

Problems such as fault tolerance and scalable synchronization can be efficiently solved using reversibility of applications. Making applications reversible by relying on computation rather than on memory is ideal for large scale parallel computing, especially for the next generation of supercomputers in which memory is expensive in terms of latency, energy, and price. In this direction, a case study is presented here in reversing a computational core, namely, Basic Linear Algebra Subprograms, which is widely used in scientific applications. A new Reversible BLAS (RBLAS) library interface has been designed, and a prototype has been implemented with two modes: (1) amore » memory-mode in which reversibility is obtained by checkpointing to memory in forward and restoring from memory in reverse, and (2) a computational-mode in which nothing is saved in the forward, but restoration is done entirely via inverse computation in reverse. The article is focused on detailed performance benchmarking to evaluate the runtime dynamics and performance effects, comparing reversible computation with checkpointing on both traditional CPU platforms and recent GPU accelerator platforms. For BLAS Level-1 subprograms, data indicates over an order of magnitude better speed of reversible computation compared to checkpointing. For BLAS Level-2 and Level-3, a more complex tradeoff is observed between reversible computation and checkpointing, depending on computational and memory complexities of the subprograms.« less

Electrophysiology of Memory-Updating Differs with Age

PubMed Central

Steiner, Genevieve Z.; Gonsalvez, Craig J.; De Blasio, Frances M.; Barry, Robert J.

2016-01-01

In oddball tasks, the P3 component of the event-related potential systematically varies with the time between target stimuli—the target-to-target interval (TTI). Longer TTIs result in larger P3 amplitudes and shorter latencies, and this pattern of results has been linked with working memory-updating processes. Given that working memory and the P3 have both been shown to diminish with age, the current study aimed to determine whether the linear relationship between P3 and TTI is compromised in healthy aging by comparing TTI effects on P3 amplitudes and latencies, and reaction time (RT), in young and older adults. Older adults were found to have an overall reduction in P3 amplitudes, longer latencies, an anterior shift in topography, a trend toward slower RTs, and a flatter linear relationship between P3 and TTI than young adults. Results suggest that the ability to maintain templates in working memory required for stimulus categorization decreases with age, and that as a result, neural compensatory mechanisms are employed. PMID:27378908

Electrophysiology of Memory-Updating Differs with Age.

PubMed

Steiner, Genevieve Z; Gonsalvez, Craig J; De Blasio, Frances M; Barry, Robert J

2016-01-01

In oddball tasks, the P3 component of the event-related potential systematically varies with the time between target stimuli-the target-to-target interval (TTI). Longer TTIs result in larger P3 amplitudes and shorter latencies, and this pattern of results has been linked with working memory-updating processes. Given that working memory and the P3 have both been shown to diminish with age, the current study aimed to determine whether the linear relationship between P3 and TTI is compromised in healthy aging by comparing TTI effects on P3 amplitudes and latencies, and reaction time (RT), in young and older adults. Older adults were found to have an overall reduction in P3 amplitudes, longer latencies, an anterior shift in topography, a trend toward slower RTs, and a flatter linear relationship between P3 and TTI than young adults. Results suggest that the ability to maintain templates in working memory required for stimulus categorization decreases with age, and that as a result, neural compensatory mechanisms are employed.

Working Memory Updating Latency Reflects the Cost of Switching between Maintenance and Updating Modes of Operation

ERIC Educational Resources Information Center

Kessler, Yoav; Oberauer, Klaus

2014-01-01

Updating and maintenance of information are 2 conflicting demands on working memory (WM). We examined the time required to update WM (updating latency) as a function of the sequence of updated and not-updated items within a list. Participants held a list of items in WM and updated a variable subset of them in each trial. Four experiments that vary…

Low latency messages on distributed memory multiprocessors

NASA Technical Reports Server (NTRS)

Rosing, Matthew; Saltz, Joel

1993-01-01

Many of the issues in developing an efficient interface for communication on distributed memory machines are described and a portable interface is proposed. Although the hardware component of message latency is less than one microsecond on many distributed memory machines, the software latency associated with sending and receiving typed messages is on the order of 50 microseconds. The reason for this imbalance is that the software interface does not match the hardware. By changing the interface to match the hardware more closely, applications with fine grained communication can be put on these machines. Based on several tests that were run on the iPSC/860, an interface that will better match current distributed memory machines is proposed. The model used in the proposed interface consists of a computation processor and a communication processor on each node. Communication between these processors and other nodes in the system is done through a buffered network. Information that is transmitted is either data or procedures to be executed on the remote processor. The dual processor system is better suited for efficiently handling asynchronous communications compared to a single processor system. The ability to send data or procedure is very flexible for minimizing message latency, based on the type of communication being performed. The test performed and the proposed interface are described.

Interval timing in genetically modified mice: a simple paradigm

PubMed Central

Balci, F.; Papachristos, E. B.; Gallistel, C. R.; Brunner, D.; Gibson, J.; Shumyatsky, G. P.

2009-01-01

We describe a behavioral screen for the quantitative study of interval timing and interval memory in mice. Mice learn to switch from a short-latency feeding station to a long-latency station when the short latency has passed without a feeding. The psychometric function is the cumulative distribution of switch latencies. Its median measures timing accuracy and its interquartile interval measures timing precision. Next, using this behavioral paradigm, we have examined mice with a gene knockout of the receptor for gastrin-releasing peptide that show enhanced (i.e. prolonged) freezing in fear conditioning. We have tested the hypothesis that the mutants freeze longer because they are more uncertain than wild types about when to expect the electric shock. The knockouts however show normal accuracy and precision in timing, so we have rejected this alternative hypothesis. Last, we conduct the pharmacological validation of our behavioral screen using D-amphetamine and methamphetamine. We suggest including the analysis of interval timing and temporal memory in tests of genetically modified mice for learning and memory and argue that our paradigm allows this to be done simply and efficiently. PMID:17696995

Interval timing in genetically modified mice: a simple paradigm.

PubMed

Balci, F; Papachristos, E B; Gallistel, C R; Brunner, D; Gibson, J; Shumyatsky, G P

2008-04-01

We describe a behavioral screen for the quantitative study of interval timing and interval memory in mice. Mice learn to switch from a short-latency feeding station to a long-latency station when the short latency has passed without a feeding. The psychometric function is the cumulative distribution of switch latencies. Its median measures timing accuracy and its interquartile interval measures timing precision. Next, using this behavioral paradigm, we have examined mice with a gene knockout of the receptor for gastrin-releasing peptide that show enhanced (i.e. prolonged) freezing in fear conditioning. We have tested the hypothesis that the mutants freeze longer because they are more uncertain than wild types about when to expect the electric shock. The knockouts however show normal accuracy and precision in timing, so we have rejected this alternative hypothesis. Last, we conduct the pharmacological validation of our behavioral screen using d-amphetamine and methamphetamine. We suggest including the analysis of interval timing and temporal memory in tests of genetically modified mice for learning and memory and argue that our paradigm allows this to be done simply and efficiently.

Armodafinil for treatment of excessive sleepiness associated with shift work disorder: a randomized controlled study.

PubMed

Czeisler, Charles A; Walsh, James K; Wesnes, Keith A; Arora, Sanjay; Roth, Thomas

2009-11-01

To assess the effect of armodafinil, 150 mg, on the physiologic propensity for sleep and cognitive performance during usual night shift hours in patients with excessive sleepiness associated with chronic (> or =3 months) shift work disorder (SWD) of moderate or greater severity. This 12-week, randomized controlled study was conducted at 42 sleep research facilities in North America from April 2 through December 23, 2004, and enrolled 254 permanent or rotating night shift workers with SWD. Entry criteria included excessive sleepiness during usual night shifts for 3 months or longer (corroborated by mean sleep latency of < or =6 minutes on a Multiple Sleep Latency Test), insomnia (sleep efficiency < or =87.5% during daytime sleep), and SWD that was judged clinically to be of moderate or greater severity. Patients received armodafinil, 150 mg, or placebo 30 to 60 minutes before each night shift. Physiologic sleep propensity during night shift hours, clinical impression of severity, patient-reported sleepiness, and cognitive function were assessed during laboratory night shifts at weeks 4, 8, and 12. Armodafinil significantly improved mean (SD) sleep latency from 2.3 (1.6) minutes at baseline to 5.3 (5.0) minutes at final visit, compared with a change from 2.4 (1.6) minutes to 2.8 (2.9) minutes in the placebo group (P<.001). Clinical condition ratings improved in more patients receiving armodafinil (79%) vs placebo (59%) (P=.001). As reported by patients' diaries, armodafinil significantly reduced sleepiness during laboratory nights (P<.001), night shifts at work (P<.001), and the commute home (P=.003). Armodafinil improved performance on standardized memory (P<.001) and attention (power, P=.001; continuity, P<.001) tests compared with placebo. Armodafinil was well tolerated and did not affect daytime sleep, as measured by polysomnography. In patients with excessive sleepiness associated with chronic SWD of moderate or greater severity, armodafinil significantly improved wakefulness during scheduled night work, raising mean nighttime sleep latency above the level considered to indicate severe sleepiness during the daytime. Armodafinil also significantly improved measures of overall clinical condition, long-term memory, and attention. clinicaltrials.gov Identifier: NCT00080288.

Drift in Neural Population Activity Causes Working Memory to Deteriorate Over Time.

PubMed

Schneegans, Sebastian; Bays, Paul M

2018-05-23

Short-term memories are thought to be maintained in the form of sustained spiking activity in neural populations. Decreases in recall precision observed with increasing number of memorized items can be accounted for by a limit on total spiking activity, resulting in fewer spikes contributing to the representation of each individual item. Longer retention intervals likewise reduce recall precision, but it is unknown what changes in population activity produce this effect. One possibility is that spiking activity becomes attenuated over time, such that the same mechanism accounts for both effects of set size and retention duration. Alternatively, reduced performance may be caused by drift in the encoded value over time, without a decrease in overall spiking activity. Human participants of either sex performed a variable-delay cued recall task with a saccadic response, providing a precise measure of recall latency. Based on a spike integration model of decision making, if the effects of set size and retention duration are both caused by decreased spiking activity, we would predict a fixed relationship between recall precision and response latency across conditions. In contrast, the drift hypothesis predicts no systematic changes in latency with increasing delays. Our results show both an increase in latency with set size, and a decrease in response precision with longer delays within each set size, but no systematic increase in latency for increasing delay durations. These results were quantitatively reproduced by a model based on a limited neural resource in which working memories drift rather than decay with time. SIGNIFICANCE STATEMENT Rapid deterioration over seconds is a defining feature of short-term memory, but what mechanism drives this degradation of internal representations? Here, we extend a successful population coding model of working memory by introducing possible mechanisms of delay effects. We show that a decay in neural signal over time predicts that the time required for memory retrieval will increase with delay, whereas a random drift in the stored value predicts no effect of delay on retrieval time. Testing these predictions in a multi-item memory task with an eye movement response, we identified drift as a key mechanism of memory decline. These results provide evidence for a dynamic spiking basis for working memory, in contrast to recent proposals of activity-silent storage. Copyright © 2018 Schneegans and Bays.

Challenges of Future High-End Computing

NASA Technical Reports Server (NTRS)

Bailey, David; Kutler, Paul (Technical Monitor)

1998-01-01

The next major milestone in high performance computing is a sustained rate of one Pflop/s (also written one petaflops, or 10(circumflex)15 floating-point operations per second). In addition to prodigiously high computational performance, such systems must of necessity feature very large main memories, as well as comparably high I/O bandwidth and huge mass storage facilities. The current consensus of scientists who have studied these issues is that "affordable" petaflops systems may be feasible by the year 2010, assuming that certain key technologies continue to progress at current rates. One important question is whether applications can be structured to perform efficiently on such systems, which are expected to incorporate many thousands of processors and deeply hierarchical memory systems. To answer these questions, advanced performance modeling techniques, including simulation of future architectures and applications, may be required. It may also be necessary to formulate "latency tolerant algorithms" and other completely new algorithmic approaches for certain applications. This talk will give an overview of these challenges.

Memory effects of Aronia melanocarpa fruit juice in a passive avoidance test in rats.

PubMed

Valcheva-Kuzmanova, Stefka V; Eftimov, Miroslav Tz; Tashev, Roman E; Belcheva, Iren P; Belcheva, Stiliana P

2014-01-01

To study the effect of Aronia melanocarpa fruit juice on memory in male Wistar rats. The juice was administered orally for 7, 14, 21 and 30 days at doses of 2.5 ml/kg, 5 ml/kg and 10 ml/kg. Memory was assessed in the one-way passive avoidance task (step through) which consisted of one training session and two retention tests (3 hours and 24 hours after training). The variables measured were the latency time to step into the dark compartment of the apparatus and the learning criterion (remaining in the illuminated compartment for at least 180 sec). Oral administration of Aronia melanocarpa fruit juice for 7 and 14 days resulted in a dose-dependent tendency to increase the latency time and the learning criterion compared to saline-treated controls but the effect failed to reach statistical significance. After 21 days of treatment, the juice dose-dependently prolonged the latency time at the retention tests, the effect being significant at doses of 5 ml/kg and 10 ml/kg. Applied for 30 days, the juice in all the tested doses increased significantly the latency time at the retention tests and the dose of 10 ml/kg significantly increased the percentage of rats reaching the learning criterion. These findings suggest that Aronia melanocarpa fruit juice could improve memory in rats. The effect is probably due to the polyphenolic ingredients of the juice which have been shown to be involved in learning and memory processes.

Age, memory type, and the phenomenology of autobiographical memory: findings from an Italian sample.

PubMed

Montebarocci, Ornella; Luchetti, Martina; Sutin, Angelina R

2014-01-01

The present research explored differences in phenomenology between two types of memories, a general self-defining memory and an earliest childhood memory. A sample of 76 Italian participants were selected and categorised into two age groups: 20-30 years and 31-40 years. The Memory Experiences Questionnaire (MEQ) was administered, taking note of latency and duration times of the narratives. Consistent with the literature, the self-defining memory differed significantly from the earliest childhood memory in terms of phenomenology, with the recency of the memory associated with more intense phenomenological experience. The self-defining memory took longer to retrieve and narrate than the earliest childhood memory. Meaningful differences also emerged between the two age groups: Participants in their 30s rated their self-defining memory as more vivid, coherent, and accessible than participants in their 20s. According to latency findings, these differences suggest an expanded period of identity consolidation for younger adults. Further applications of the MEQ should be carried out to replicate these results with other samples of young adults.

A steady state visually evoked potential investigation of memory and ageing.

PubMed

Macpherson, Helen; Pipingas, Andrew; Silberstein, Richard

2009-04-01

Old age is generally accompanied by a decline in memory performance. Specifically, neuroimaging and electrophysiological studies have revealed that there are age-related changes in the neural correlates of episodic and working memory. This study investigated age-associated changes in the steady state visually evoked potential (SSVEP) amplitude and latency associated with memory performance. Participants were 15 older (59-67 years) and 14 younger (20-30 years) adults who performed an object working memory (OWM) task and a contextual recognition memory (CRM) task, whilst the SSVEP was recorded from 64 electrode sites. Retention of a single object in the low demand OWM task was characterised by smaller frontal SSVEP amplitude and latency differences in older adults than in younger adults, indicative of an age-associated reduction in neural processes. Recognition of visual images in the more difficult CRM task was accompanied by larger, more sustained SSVEP amplitude and latency decreases over temporal parietal regions in older adults. In contrast, the more transient, frontally mediated pattern of activity demonstrated by younger adults suggests that younger and older adults utilize different neural resources to perform recognition judgements. The results provide support for compensatory processes in the aging brain; at lower task demands, older adults demonstrate reduced neural activity, whereas at greater task demands neural activity is increased.

Memory-dependent adjustment of vocal response latencies in a territorial songbird.

PubMed

Geberzahn, Nicole; Hultsch, Henrike; Todt, Dietmar

2013-06-01

Vocal interactions in songbirds can be used as a model system to investigate the interplay of intrinsic singing programmes (e.g. influences from vocal memories) and external variables (e.g. social factors). When characterizing vocal interactions between territorial rivals two aspects are important: (1) the timing of songs in relation to the conspecific's singing and (2) the use of a song pattern that matches the rival's song. Responses in both domains can be used to address a territorial rival. This study is the first to investigate the relation of the timing of vocal responses to (1) the vocal memory of a responding subject and (2) the selection of the song pattern that the subject uses as a response. To this end, we conducted interactive playback experiments with adult nightingales (Luscinia megarhynchos) that had been hand-reared and tutored in the laboratory. We analysed the subjects' vocal response latencies towards broadcast playback stimuli that they either had in their own vocal repertoire (songs shared with playback) or that they had not heard before (unknown songs). Likewise, we compared vocal response latencies between responses that matched the stimulus song and those that did not. Our findings showed that the latency of singing in response to the playback was shorter for shared versus unknown song stimuli when subjects overlapped the playback stimuli with their own song. Moreover birds tended to overlap faster when vocally matching the stimulus song rather than when replying with a non-matching song type. We conclude that memory of song patterns influenced response latencies and discuss possible mechanisms. Copyright © 2012 Elsevier Ltd. All rights reserved.

ERP evaluation of auditory sensory memory systems in adults with intellectual disability.

PubMed

Ikeda, Kazunari; Hashimoto, Souichi; Hayashi, Akiko; Kanno, Atsushi

2009-01-01

Auditory sensory memory stage can be functionally divided into two subsystems; transient-detector system and permanent feature-detector system (Naatanen, 1992). We assessed these systems in persons with intellectual disability by measuring event-related potentials (ERPs) N1 and mismatch negativity (MMN), which reflect the two auditory subsystems, respectively. Added to these, P3a (an ERP reflecting stage after sensory memory) was evaluated. Either synthesized vowels or simple tones were delivered during a passive oddball paradigm to adults with and without intellectual disability. ERPs were recorded from midline scalp sites (Fz, Cz, and Pz). Relative to control group, participants with the disability exhibited greater N1 latency and less MMN amplitude. The results for N1 amplitude and MMN latency were basically comparable between both groups. IQ scores in participants with the disability revealed no significant relation with N1 and MMN measures, whereas the IQ scores tended to increase significantly as P3a latency reduced. These outcomes suggest that persons with intellectual disability might own discrete malfunctions for the two detector systems in auditory sensory-memory stage. Moreover, the processes following sensory memory might be partly related to a determinant of mental development.

Local wavelet transform: a cost-efficient custom processor for space image compression

NASA Astrophysics Data System (ADS)

Masschelein, Bart; Bormans, Jan G.; Lafruit, Gauthier

2002-11-01

Thanks to its intrinsic scalability features, the wavelet transform has become increasingly popular as decorrelator in image compression applications. Throuhgput, memory requirements and complexity are important parameters when developing hardware image compression modules. An implementation of the classical, global wavelet transform requires large memory sizes and implies a large latency between the availability of the input image and the production of minimal data entities for entropy coding. Image tiling methods, as proposed by JPEG2000, reduce the memory sizes and the latency, but inevitably introduce image artefacts. The Local Wavelet Transform (LWT), presented in this paper, is a low-complexity wavelet transform architecture using a block-based processing that results in the same transformed images as those obtained by the global wavelet transform. The architecture minimizes the processing latency with a limited amount of memory. Moreover, as the LWT is an instruction-based custom processor, it can be programmed for specific tasks, such as push-broom processing of infinite-length satelite images. The features of the LWT makes it appropriate for use in space image compression, where high throughput, low memory sizes, low complexity, low power and push-broom processing are important requirements.

[Event-related potentials P₃₀₀ with memory function and psychopathology in first-episode paranoid schizophrenia].

PubMed

Liu, Wei-bo; Chen, Qiao-zhen; Yin, Hou-min; Zheng, Lei-lei; Yu, Shao-hua; Chen, Yi-ping; Li, Hui-chun

2011-11-01

To investigate the variability of event-related potentials P(300) and the relationship with memory function/psychopathology in patients with first-episode paranoid schizophrenia. Thirty patients with first-episode paranoid schizophrenia (patient group) and twenty health subjects (control group) were enrolled in the study. The auditory event-related potentials P₃₀₀ at the scalp electrodes Cz, Pz and Wechsler Memory Scale (WMS) were examined in both groups, Positive And Negative Syndrome Scale (PANSS) was evaluated in patient group. In comparison with control group, patients had longer latency of P₃₀₀ [(390.6 ± 47.6)ms at Cz and (393.3 ± 50.1)ms at Pz] (P<0.01), lower amplitude of P₃₀₀ [(7.7 ± 3.4) μV at Cz and (8.5 ± 3.9)μV at Pz] (P<0.05-0.01). The memory quotient (88.1 ± 10.0) scores and short-term memory, immediate memory in patient group were damaged significantly (P<0.05-0.01). In patient group, the latency of P300 was correlated positively with PANSS scores and negatively with WMS scores (P<0.05-0.01). First-episode paranoid schizophrenia has memory deficit, which can be evaluated comprehensively by P₃₀₀ and WMS. The longer latency of P₃₀₀ might be associated with the increased severity of first-episode paranoid schizophrenia.

Dopamine D1 receptors are responsible for stress-induced emotional memory deficit in mice.

PubMed

Wang, Yongfu; Wu, Jing; Zhu, Bi; Li, Chaocui; Cai, Jing-Xia

2012-03-01

It is established that stress impairs spatial learning and memory via the hypothalamus-pituitary-adrenal axis response. Dopamine D1 receptors were also shown to be responsible for a stress-induced deficit of working memory. However, whether stress affects the subsequent emotional learning and memory is not elucidated yet. Here, we employed the well-established one-trial step-through task to study the effect of an acute psychological stress (induced by tail hanging for 5, 10, or 20 min) on emotional learning and memory, and the possible mechanisms as well. We demonstrated that tail hanging induced an obvious stress response. Either an acute tail-hanging stress or a single dose of intraperitoneally injected dopamine D1 receptor antagonist (SCH23390) significantly decreased the step-through latency in the one-trial step-through task. However, SCH23390 prevented the acute tail-hanging stress-induced decrease in the step-through latency. In addition, the effects of tail-hanging stress and/or SCH23390 on the changes in step-through latency were not through non-memory factors such as nociceptive perception and motor function. Our data indicate that the hyperactivation of dopamine D1 receptors mediated the stress-induced deficit of emotional learning and memory. This study may have clinical significance given that psychological stress is considered to play a role in susceptibility to some mental diseases such as depression and post-traumatic stress disorder.

The inhibitory avoidance discrimination task to investigate accuracy of memory.

PubMed

Atucha, Erika; Roozendaal, Benno

2015-01-01

The present study was aimed at developing a new inhibitory avoidance task, based on training and/or testing rats in multiple contexts, to investigate accuracy of memory. In the first experiment, male Sprague-Dawley rats were given footshock in an inhibitory avoidance apparatus and, 48 h later, retention latencies of each rat were assessed in the training apparatus (Shock box) as well as in a novel, contextually modified, apparatus. Retention latencies in the Shock box were significantly longer than those in the Novel box, indicating accurate memory of the training context. When the noradrenergic stimulant yohimbine (0.3 mg/kg, sc) was administered after the training, 48-h retention latencies in the Shock box, but not Novel box, were increased, indicating that the noradrenergic activation enhanced memory of the training experience without reducing memory accuracy. In the second experiment, rats were trained on an inhibitory avoidance discrimination task: They were first trained in an inhibitory avoidance apparatus without footshock (Non-Shock box), followed 1 min later by footshock training in a contextually modified apparatus (Shock box). Forty-eight-hour retention latencies in the Shock and Non-Shock boxes did not differ from each other but were both significantly longer than those in a Novel box, indicating that rats remembered the two training contexts but did not have episodic-like memory of the association of footshock with the correct training context. When the interval between the two training episodes was increased to 2 min, rats showed accurate memory of the association of footshock with the training context. Yohimbine administered after the training also enhanced rats' ability to remember in which training context they had received actual footshock. These findings indicate that the inhibitory avoidance discrimination task is a novel variant of the well-established inhibitory avoidance task suitable to investigate accuracy of memory.

Evoked Potentials and Memory/Cognition Tests Validate Brain Atrophy as Measured by 3T MRI (NeuroQuant) in Cognitively Impaired Patients.

PubMed

Braverman, Eric R; Blum, Kenneth; Hussman, Karl L; Han, David; Dushaj, Kristina; Li, Mona; Marin, Gabriela; Badgaiyan, Rajendra D; Smayda, Richard; Gold, Mark S

2015-01-01

To our knowledge, this is the largest study evaluating relationships between 3T Magnetic Resonance Imaging (MRI) and P300 and memory/cognitive tests in the literature. The 3T MRI using NeuroQuant has an increased resolution 15 times that of 1.5T MRI. Utilizing NeuroQuant 3T MRI as a diagnostic tool in primary care, subjects (N=169; 19-90 years) displayed increased areas of anatomical atrophy: 34.62% hippocampal atrophy (N=54), 57.14% central atrophy (N=88), and 44.52% temporal atrophy (N=69). A majority of these patients exhibited overlap in measured areas of atrophy and were cognitively impaired. These results positively correlated with decreased P300 values and WMS-III (WMS-III) scores differentially across various brain loci. Delayed latency (p=0.0740) was marginally associated with temporal atrophy; reduced fractional anisotropy (FA) in frontal lobes correlated with aging, delayed P300 latency, and decreased visual and working memory (p=0.0115). Aging and delayed P300 latency correlated with lower FA. The correlation between working memory and reduced FA in frontal lobes is marginally significant (p=0.0787). In the centrum semiovale (CS), reduced FA correlated with visual memory (p=0.0622). Lower demyelination correlated with higher P300 amplitude (p=0.0002). Compared to males, females have higher demyelination (p=0.0064). Along these lines, the higher the P300 amplitude, the lower the bilateral atrophy (p=0.0165). Hippocampal atrophy correlated with increased auditory memory and gender, especially in males (p=0.0087). In considering temporal lobe atrophy correlations: delayed P300 latency and high temporal atrophy (p=0.0740); high auditory memory and low temporal atrophy (p=0.0417); and high working memory and low temporal atrophy (p=0.0166). Central atrophy correlated with aging and immediate memory (p=0.0294): the higher the immediate memory, the lower the central atrophy. Generally, the validation of brain atrophy by P300 and WMS-III could lead to cost-effective methods utilizable in primary care medicine following further confirmation.

Evoked Potentials and Memory/Cognition Tests Validate Brain Atrophy as Measured by 3T MRI (NeuroQuant) in Cognitively Impaired Patients

PubMed Central

Braverman, Eric R.; Blum, Kenneth; Hussman, Karl L.; Han, David; Dushaj, Kristina; Li, Mona; Marin, Gabriela; Badgaiyan, Rajendra D.; Smayda, Richard; Gold, Mark S.

2015-01-01

To our knowledge, this is the largest study evaluating relationships between 3T Magnetic Resonance Imaging (MRI) and P300 and memory/cognitive tests in the literature. The 3T MRI using NeuroQuant has an increased resolution 15 times that of 1.5T MRI. Utilizing NeuroQuant 3T MRI as a diagnostic tool in primary care, subjects (N=169; 19–90 years) displayed increased areas of anatomical atrophy: 34.62% hippocampal atrophy (N=54), 57.14% central atrophy (N=88), and 44.52% temporal atrophy (N=69). A majority of these patients exhibited overlap in measured areas of atrophy and were cognitively impaired. These results positively correlated with decreased P300 values and WMS-III (WMS-III) scores differentially across various brain loci. Delayed latency (p=0.0740) was marginally associated with temporal atrophy; reduced fractional anisotropy (FA) in frontal lobes correlated with aging, delayed P300 latency, and decreased visual and working memory (p=0.0115). Aging and delayed P300 latency correlated with lower FA. The correlation between working memory and reduced FA in frontal lobes is marginally significant (p=0.0787). In the centrum semiovale (CS), reduced FA correlated with visual memory (p=0.0622). Lower demyelination correlated with higher P300 amplitude (p=0.0002). Compared to males, females have higher demyelination (p=0.0064). Along these lines, the higher the P300 amplitude, the lower the bilateral atrophy (p=0.0165). Hippocampal atrophy correlated with increased auditory memory and gender, especially in males (p=0.0087). In considering temporal lobe atrophy correlations: delayed P300 latency and high temporal atrophy (p=0.0740); high auditory memory and low temporal atrophy (p=0.0417); and high working memory and low temporal atrophy (p=0.0166). Central atrophy correlated with aging and immediate memory (p=0.0294): the higher the immediate memory, the lower the central atrophy. Generally, the validation of brain atrophy by P300 and WMS-III could lead to cost-effective methods utilizable in primary care medicine following further confirmation. PMID:26244349

Optical interconnection network for parallel access to multi-rank memory in future computing systems.

PubMed

Wang, Kang; Gu, Huaxi; Yang, Yintang; Wang, Kun

2015-08-10

With the number of cores increasing, there is an emerging need for a high-bandwidth low-latency interconnection network, serving core-to-memory communication. In this paper, aiming at the goal of simultaneous access to multi-rank memory, we propose an optical interconnection network for core-to-memory communication. In the proposed network, the wavelength usage is delicately arranged so that cores can communicate with different ranks at the same time and broadcast for flow control can be achieved. A distributed memory controller architecture that works in a pipeline mode is also designed for efficient optical communication and transaction address processes. The scaling method and wavelength assignment for the proposed network are investigated. Compared with traditional electronic bus-based core-to-memory communication, the simulation results based on the PARSEC benchmark show that the bandwidth enhancement and latency reduction are apparent.

A Bandwidth-Optimized Multi-Core Architecture for Irregular Applications

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

Secchi, Simone; Tumeo, Antonino; Villa, Oreste

This paper presents an architecture template for next-generation high performance computing systems specifically targeted to irregular applications. We start our work by considering that future generation interconnection and memory bandwidth full-system numbers are expected to grow by a factor of 10. In order to keep up with such a communication capacity, while still resorting to fine-grained multithreading as the main way to tolerate unpredictable memory access latencies of irregular applications, we show how overall performance scaling can benefit from the multi-core paradigm. At the same time, we also show how such an architecture template must be coupled with specific techniquesmore » in order to optimize bandwidth utilization and achieve the maximum scalability. We propose a technique based on memory references aggregation, together with the related hardware implementation, as one of such optimization techniques. We explore the proposed architecture template by focusing on the Cray XMT architecture and, using a dedicated simulation infrastructure, validate the performance of our template with two typical irregular applications. Our experimental results prove the benefits provided by both the multi-core approach and the bandwidth optimization reference aggregation technique.« less

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

PubMed

Callahan-Flintoft, Chloe; Wyble, Brad

2017-11-01

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

The role of nitric oxide in the PKA inhibitor induced spatial memory deficits in rat: involvement of choline acetyltransferase.

PubMed

Najafi, Sheyda; Payandemehr, Borna; Tabrizian, Kaveh; Shariatpanahi, Marjan; Nassireslami, Ehsan; Azami, Kian; Mohammadi, Mojdeh; Asadi, Farideh; Roghani, Ali; Sharifzadeh, Mohammad

2013-08-15

Several lines of evidence show that cAMP-PKA signaling pathway plays critical role in memory functions and suggest nitric oxide as an important modulator in learning and memory. In this study, we assessed the effects of intra-hippocampal infusion of H-89, a selective PKAII inhibitor, and 1400 W, a selective inducible nitric oxide synthase (iNOS) inhibitor, on spatial memory in rats. By using the Morris water maze, spatial memory retention parameters were examined 48 h after the infusions through measuring escape latency, traveled distance, and swimming speed. The rats receiving intra-hippocampal infusions of 1400 W (100 µM/side) showed a significant reduction (*P<0.05) in escape latency and traveled distance in comparison with the control saline group. In contrast, a significant increase (**P<0.01) in escape latency and traveled distance was observed after infusion of 10 µM H-89. Moreover, among combination groups, co-administration of 1400 W (400 µM/side) with 10 µM/side of H-89 caused a significant reduction (*P<0.05) in escape latency and traveled distance in comparison with the H-89 group. Also, we evaluated the molecular effects of 1400 W on the expression of choline acetyltransferase (ChAT), a cholinergic marker, in the CA1 region of the hippocampus and medial septal area (MSA). Immunohistochemical analysis of post-training bilateral intra-hippocampal infusion of 1400 W revealed a significant increase in ChAT immunoreactivity levels in both the CA1 and the MSA regions. Overall, the results suggest that 1400 W has protective effect against H89-induced spatial memory impairment. Moreover, the observed memory improvements caused by 1400 W infusions, might be due to interaction of iNOS with the cholinergic system. © 2013 Elsevier B.V. All rights reserved.

Evaluation of the anaesthetic properties and tolerance of 1:100,000 articaine versus 1:100,000 lidocaine. A comparative study in surgery of the lower third molar

PubMed Central

Barona-Dorado, Cristina; Martín-Arés, María; Cortés-Bretón-Brinkman, Jorge; Martínez-González, José M.

2012-01-01

Objectives: To evaluate the anaesthetic properties and tolerance of articaine versus lidocaine at equal vasoconstrictor concentration. Study Design: A total of 96 male and female patients who underwent surgical treatment of the lower third molar participated. Patients were randomly assigned to articaine hydrochloride with epinephrine 1:100,000 and lidocaine hydrochloride with epinephrine 1:100,000. The variables analysed were latency period, duration of anaesthetic effect, tolerance and adverse reactions. Results: Both the latency period and the duration of anaesthetic effect were greater for articaine, although the differences were not statistically significant. Latency: mean difference of 2.70 ± 2.12 minutes (95%CI of -1.51 minutes - 6.92 minutes). Duration: mean difference of -33 minutes 5 seconds ± 31 minutes (95% CI -1 hour 35 minutes - 29 minutes). There were 4 adverse events that did not require the patients to be withdrawn from the study. Conclusions: The anaesthetics in this study have very similar properties for use in surgery and have demonstrated a good safety and tolerability profile Key words: Articaine, lidocaine, vasoconstrictor, adverse reactions. PMID:22143691

Transcriptomic Analysis Implicates the p53 Signaling Pathway in the Establishment of HIV-1 Latency in Central Memory CD4 T Cells in an In Vitro Model

PubMed Central

White, Cory H.; Moesker, Bastiaan; Beliakova-Bethell, Nadejda; Martins, Laura J.; Richman, Douglas D.; Planelles, Vicente; Woelk, Christopher H.

2016-01-01

The search for an HIV-1 cure has been greatly hindered by the presence of a viral reservoir that persists despite antiretroviral therapy (ART). Studies of HIV-1 latency in vivo are also complicated by the low proportion of latently infected cells in HIV-1 infected individuals. A number of models of HIV-1 latency have been developed to examine the signaling pathways and viral determinants of latency and reactivation. A primary cell model of HIV-1 latency, which incorporates the generation of primary central memory CD4 T cells (TCM), full-length virus infection (HIVNL4-3) and ART to suppress virus replication, was used to investigate the establishment of HIV latency using RNA-Seq. Initially, an investigation of host and viral gene expression in the resting and activated states of this model indicated that the resting condition was reflective of a latent state. Then, a comparison of the host transcriptome between the uninfected and latently infected conditions of this model identified 826 differentially expressed genes, many of which were related to p53 signaling. Inhibition of the transcriptional activity of p53 by pifithrin-α during HIV-1 infection reduced the ability of HIV-1 to be reactivated from its latent state by an unknown mechanism. In conclusion, this model may be used to screen latency reversing agents utilized in shock and kill approaches to cure HIV, to search for cellular markers of latency, and to understand the mechanisms by which HIV-1 establishes latency. PMID:27898737

Transcriptomic Analysis Implicates the p53 Signaling Pathway in the Establishment of HIV-1 Latency in Central Memory CD4 T Cells in an In Vitro Model.

PubMed

White, Cory H; Moesker, Bastiaan; Beliakova-Bethell, Nadejda; Martins, Laura J; Spina, Celsa A; Margolis, David M; Richman, Douglas D; Planelles, Vicente; Bosque, Alberto; Woelk, Christopher H

2016-11-01

The search for an HIV-1 cure has been greatly hindered by the presence of a viral reservoir that persists despite antiretroviral therapy (ART). Studies of HIV-1 latency in vivo are also complicated by the low proportion of latently infected cells in HIV-1 infected individuals. A number of models of HIV-1 latency have been developed to examine the signaling pathways and viral determinants of latency and reactivation. A primary cell model of HIV-1 latency, which incorporates the generation of primary central memory CD4 T cells (TCM), full-length virus infection (HIVNL4-3) and ART to suppress virus replication, was used to investigate the establishment of HIV latency using RNA-Seq. Initially, an investigation of host and viral gene expression in the resting and activated states of this model indicated that the resting condition was reflective of a latent state. Then, a comparison of the host transcriptome between the uninfected and latently infected conditions of this model identified 826 differentially expressed genes, many of which were related to p53 signaling. Inhibition of the transcriptional activity of p53 by pifithrin-α during HIV-1 infection reduced the ability of HIV-1 to be reactivated from its latent state by an unknown mechanism. In conclusion, this model may be used to screen latency reversing agents utilized in shock and kill approaches to cure HIV, to search for cellular markers of latency, and to understand the mechanisms by which HIV-1 establishes latency.

Effects of the histamine H₃ receptor antagonist ABT-239 on cognition and nicotine-induced memory enhancement in mice.

PubMed

Kruk, Marta; Miszkiel, Joanna; McCreary, Andrew C; Przegaliński, Edmund; Filip, Małgorzata; Biała, Grażyna

2012-01-01

The strong correlation between central histaminergic and cholinergic pathways on cognitive processes has been reported extensively. However, the role of histamine H(3) receptor mechanisms interacting with nicotinic mechanisms has not previously been extensively investigated. The current study was conducted to determine the interactions of nicotinic and histamine H(3) receptor systems with regard to learning and memory function using a modified elevated plus-maze test in mice. In this test, the latency for mice to move from the open arm to the enclosed arm (i.e., transfer latency) was used as an index of memory. We tested whether ABT-239 (4-(2-{2-[(2R)-2-methylpyrrolidinyl]ethyl}-benzofuran-5-yl), an H(3) receptor antagonist/inverse agonist, had influence on two different stages of memory, i.e., memory acquisition and consolidation (administered prior to or immediately after the first trial, respectively) and whether ABT-239 influenced nicotine-induced memory enhancement. Our results revealed that the acute administration of nicotine (0.035 and 0.175 mg/kg), but not of ABT-239 (0.1-3 mg/kg) reduced transfer latency in the acquisition and consolidation phases. In combination studies, concomitant administration of either ABT-239 (1 and 3 mg/kg) and nicotine (0.035 mg/kg), or ABT-239 (0.1 mg/kg) and nicotine (0.0175 mg/kg) further increased nicotine-induced improvement in both memory acquisition and consolidation. The present data confirm an important role for H(3) receptors in regulating nicotine-induced mnemonic effects since inhibition of H(3) receptors augmented nicotine-induced memory enhancement in mice.

Perception, memory and aesthetics of indeterminate art.

PubMed

Ishai, Alumit; Fairhall, Scott L; Pepperell, Robert

2007-07-12

Indeterminate art, in which familiar objects are only suggestive, invokes a perceptual conundrum as apparently detailed and vivid images resist identification. We hypothesized that compared with paintings that depict meaningful content, object recognition in indeterminate images would be delayed, and tested whether aesthetic affect depends on meaningful content. Subjects performed object recognition and judgment of aesthetic affect tasks. Response latencies were significantly longer for indeterminate images and subjects perceived recognizable objects in 24% of these paintings. Although the aesthetic affect rating of all paintings was similar, judgement latencies for the indeterminate paintings were significantly longer. A surprise memory test revealed that more representational than indeterminate paintings were remembered and that affective strength increased the probability of subsequent recall. Our results suggest that perception and memory of art depend on semantic aspects, whereas, aesthetic affect depends on formal visual features. The longer latencies associated with indeterminate paintings reflect the underlying cognitive processes that mediate object resolution. Indeterminate art works therefore comprise a rich set of stimuli with which the neural correlates of visual perception can be investigated.

Lexical access and evoked traveling alpha waves

PubMed Central

Zauner, Andrea; Gruber, Walter; Himmelstoß, Nicole Alexandra; Lechinger, Julia; Klimesch, Wolfgang

2014-01-01

Retrieval from semantic memory is usually considered within a time window around 300–600 ms. Here we suggest that lexical access already occurs at around 100 ms. This interpretation is based on the finding that semantically rich and frequent words exhibit a significantly shorter topographical latency difference between the site with the shortest P1 latency (leading site) and that with the longest P1 latency (trailing site). This latency difference can be described in terms of an evoked traveling alpha wave as was already shown in earlier studies. PMID:24486978

Investigation of neuropsychopharmacological effects of a polyherbal formulation on the learning and memory process in rats.

PubMed

Shah, Js; Goyal, Rk

2011-04-01

To investigate the neuropsychopharmacological effect of a polyherbal formulation (PHF) on the learning and memory processes in rats. PHF contains Withania somnifera (Ashwagandha), Nardostachys jatamansi (Jatamansi), Rauwolfia serpentina (Sarpagandha), Evolvulus alsinoides (Shankhpushpi), Asparagus racemosus (Shatavari), Emblica officinalis (Amalki), Mucuna pruriens (Kauch bij extract), Hyoscyamus niger (Khurasani Ajmo), Mineral resin (Shilajit), Pearl (Mukta Shukhti Pishti), and coral calcium (Praval pishti). Its effect (500 mg / kg, p.o.) on the learning and memory processes was tested. The activity of PHF on memory acquisition and retention was studied using passive avoidance learning and elevated plus maze model (EPM) in rats. The animals treated with PHF showed a significant decrease in transfer latency as compared to the control group in EPM. PHF also produced significant improvement in passive avoidance acquisition and memory retrieval, as compared to the controls and reduced the latency to reach the shock free zone (SFZ) after 24 hours. The PHF produces significant improvement in passive avoidance acquisition and memory retrieval in rats, which needs further investigation.

Reducing the PAPR in FBMC-OQAM systems with low-latency trellis-based SLM technique

NASA Astrophysics Data System (ADS)

Bulusu, S. S. Krishna Chaitanya; Shaiek, Hmaied; Roviras, Daniel

2016-12-01

Filter-bank multi-carrier (FBMC) modulations, and more specifically FBMC-offset quadrature amplitude modulation (OQAM), are seen as an interesting alternative to orthogonal frequency division multiplexing (OFDM) for the 5th generation radio access technology. In this paper, we investigate the problem of peak-to-average power ratio (PAPR) reduction for FBMC-OQAM signals. Recently, it has been shown that FBMC-OQAM with trellis-based selected mapping (TSLM) scheme not only is superior to any scheme based on symbol-by-symbol approach but also outperforms that of the OFDM with classical SLM scheme. This paper is an extension of that work, where we analyze the TSLM in terms of computational complexity, required hardware memory, and latency issues. We have proposed an improvement to the TSLM, which requires very less hardware memory, compared to the originally proposed TSLM, and also have low latency. Additionally, the impact of the time duration of partial PAPR on the performance of TSLM is studied, and its lower bound has been identified by proposing a suitable time duration. Also, a thorough and fair comparison of performance has been done with an existing trellis-based scheme proposed in literature. The simulation results show that the proposed low-latency TSLM yields better PAPR reduction performance with relatively less hardware memory requirements.

Scaling Irregular Applications through Data Aggregation and Software Multithreading

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

Morari, Alessandro; Tumeo, Antonino; Chavarría-Miranda, Daniel

Bioinformatics, data analytics, semantic databases, knowledge discovery are emerging high performance application areas that exploit dynamic, linked data structures such as graphs, unbalanced trees or unstructured grids. These data structures usually are very large, requiring significantly more memory than available on single shared memory systems. Additionally, these data structures are difficult to partition on distributed memory systems. They also present poor spatial and temporal locality, thus generating unpredictable memory and network accesses. The Partitioned Global Address Space (PGAS) programming model seems suitable for these applications, because it allows using a shared memory abstraction across distributed-memory clusters. However, current PGAS languagesmore » and libraries are built to target regular remote data accesses and block transfers. Furthermore, they usually rely on the Single Program Multiple Data (SPMD) parallel control model, which is not well suited to the fine grained, dynamic and unbalanced parallelism of irregular applications. In this paper we present {\\bf GMT} (Global Memory and Threading library), a custom runtime library that enables efficient execution of irregular applications on commodity clusters. GMT integrates a PGAS data substrate with simple fork/join parallelism and provides automatic load balancing on a per node basis. It implements multi-level aggregation and lightweight multithreading to maximize memory and network bandwidth with fine-grained data accesses and tolerate long data access latencies. A key innovation in the GMT runtime is its thread specialization (workers, helpers and communication threads) that realize the overall functionality. We compare our approach with other PGAS models, such as UPC running using GASNet, and hand-optimized MPI code on a set of typical large-scale irregular applications, demonstrating speedups of an order of magnitude.« less

Effects of the antidepressant drug moclobemide on learning and memory in rats.

PubMed

Getova, D; Dimitrova, D; Roukounakis, I

2003-12-01

Moclobemide is a well known drug with antidepressant action. The aim of this study was to investigate the effects of moclobemide on learning and memory processes in Sprague Dawley rats. Over a 5-day period, learning sessions with 30 trials per day and memory retention tests were performed. The conditioned responses (avoidances), the unconditioned responses (escapes) and the intertrial crossings were observed. An active avoidance test was carried out using a shuttle box. Two passive avoidance tests were used: step-through (using a light chamber) and step-down (using a platform). In the step-through passive avoidance test, the learning and retention sessions consisted of three trials each and the latency of reaction times (the rat remaining in the light chamber for more than 180 sec) was used as criterion. In the step-down passive avoidance test, learning and retention sessions consisted of two trials and the latency of reaction times (the rat remaining on the platform for 60 sec) was used as criterion. In the active avoidance tests, moclobemide dose-dependently increased the number of avoidances during learning sessions and maintained this number in memory retention tests. Moclobemide did not alter the number of escapes, but did increase motor activity. In the passive avoidance tests, moclobemide also increased the latency of reaction times in learning and short memory retrieval tests. These findings suggest that moclobemide improves learning and memory processes in active and passive avoidance tests and has a cognition-enhancing effect. (c) 2003 Prous Science

Stream Processors

NASA Astrophysics Data System (ADS)

Erez, Mattan; Dally, William J.

Stream processors, like other multi core architectures partition their functional units and storage into multiple processing elements. In contrast to typical architectures, which contain symmetric general-purpose cores and a cache hierarchy, stream processors have a significantly leaner design. Stream processors are specifically designed for the stream execution model, in which applications have large amounts of explicit parallel computation, structured and predictable control, and memory accesses that can be performed at a coarse granularity. Applications in the streaming model are expressed in a gather-compute-scatter form, yielding programs with explicit control over transferring data to and from on-chip memory. Relying on these characteristics, which are common to many media processing and scientific computing applications, stream architectures redefine the boundary between software and hardware responsibilities with software bearing much of the complexity required to manage concurrency, locality, and latency tolerance. Thus, stream processors have minimal control consisting of fetching medium- and coarse-grained instructions and executing them directly on the many ALUs. Moreover, the on-chip storage hierarchy of stream processors is under explicit software control, as is all communication, eliminating the need for complex reactive hardware mechanisms.

[Cortical potentials evoked to response to a signal to make a memory-guided saccade].

PubMed

Slavutskaia, M V; Moiseeva, V V; Shul'govskiĭ, V V

2010-01-01

The difference in parameters of visually guided and memory-guided saccades was shown. Increase in the memory-guided saccade latency as compared to that of the visually guided saccades may indicate the deceleration of saccadic programming on the basis of information extraction from the memory. The comparison of parameters and topography of evoked components N1 and P1 of the evoked potential on the signal to make a memory- or visually guided saccade suggests that the early stage of the saccade programming associated with the space information processing is performed predominantly with top-down attention mechanism before the memory-guided saccade and bottom-up mechanism before the visually guided saccade. The findings show that the increase in the latency of the memory-guided saccades is connected with decision making at the central stage of the saccade programming. We proposed that wave N2, which develops in the middle of the latent period of the memory-guided saccades, is correlated with this process. Topography and spatial dynamics of components N1, P1 and N2 testify that the memory-guided saccade programming is controlled by the frontal mediothalamic system of selective attention and left-hemispheric brain mechanisms of motor attention.

Rapid recovery from transient faults in the fault-tolerant processor with fault-tolerant shared memory

NASA Technical Reports Server (NTRS)

Harper, Richard E.; Butler, Bryan P.

1990-01-01

The Draper fault-tolerant processor with fault-tolerant shared memory (FTP/FTSM), which is designed to allow application tasks to continue execution during the memory alignment process, is described. Processor performance is not affected by memory alignment. In addition, the FTP/FTSM incorporates a hardware scrubber device to perform the memory alignment quickly during unused memory access cycles. The FTP/FTSM architecture is described, followed by an estimate of the time required for channel reintegration.

Interference resolution in major depression.

PubMed

Joormann, Jutta; Nee, Derek Evan; Berman, Marc G; Jonides, John; Gotlib, Ian H

2010-03-01

In two experiments, we investigated individual differences in the ability to resolve interference in participants diagnosed with major depressive disorder (MDD). Participants were administered the "Ignore/Suppress" task, a short-term memory task composed of two steps. In Step 1 ("ignore"), participants were instructed to memorize a set of stimuli while ignoring simultaneously presented irrelevant material. In Step 2 ("suppress"), participants were instructed to forget a subset of the previously memorized material. The ability to resolve interference was indexed by response latencies on two recognition tasks in which participants decided whether a probe was a member of the target set. In Step 1, we compared response latencies to probes from the to-be-ignored list with response latencies to nonrecently presented items. In Step 2, we compared response latencies to probes from the to-be-suppressed list with response latencies to nonrecently presented items. The results indicate that, compared with control participants, depressed participants exhibited increased interference in the "suppress" but not in the "ignore" step of the task, when the stimuli were negative words. No group differences were obtained when we presented letters instead of emotional words. These findings indicate that depression is associated with difficulty in removing irrelevant negative material from short-term memory.

The Orexin Antagonist SB-649868 Promotes and Maintains Sleep in Men with Primary Insomnia

PubMed Central

Bettica, Paolo; Squassante, Lisa; Zamuner, Stefano; Nucci, Gianluca; Danker-Hopfe, Heidi; Ratti, Emiliangelo

2012-01-01

Study Objectives: To assess the acute effects of SB-649868 in male subjects with Primary Insomnia with regard to (1) objective and subjective sleep parameters, (2) safety and tolerability, (3) next-day residual effects. Design: Multicenter, randomized, double-blind, placebo-controlled crossover study using a complete set of Williams orthogonal Latin Squares Setting: 9 sleep centers in Germany Patients: 52 male subjects with a diagnosis of primary insomnia (difficulty in sleep initiation and maintenance) confirmed by polysomnography Interventions: SB-649868 (10, 30, 60 mg) and placebo administered after dinner 90 minutes before bedtime Measurements and Results: Sleep effects assessed by polysomnography during 2 consecutive nights and by sleep questionnaires completed by subjects after each night at the sleep laboratory. Safety and tolerability were assessed by adverse events collection, electrocardiogram (ECG), vital signs, laboratory tests. Next-day residual effects were assessed by Digit Symbol Substitution Test, and modified Verbal Learning Memory Test administered at “lights on” after night 2. SB-649868 significantly reduced latency to persistent sleep, wake after sleep onset (WASO), and increased total sleep time (TST) compared to placebo. A dose-dependent effect was observed. A dose-dependent increase in absolute and percent REM sleep and reduction in REM sleep latency was observed mainly at the 60-mg dose. SB-649868 was well tolerated with inconsistent next day residual effects. SB-649868 sleep effects were correlated with SB-649868 circulating levels. Conclusion: The data demonstrate the sleep-promoting properties of the orexin antagonist SB-649868 in male patients with insomnia. Clinical Trials Information: This study was registered on ClinicalTrials.gov with the following identifier: NCT00426816. URL: http://www.clinicaltrial.gov/ct2/show/NCT00426816?term=649868&rank=5. Citation: Bettica P; Squassante L; Zamuner S; Nucci G; Danker-Hopfe H; Ratti E. The orexin antagonist SB-649868 promotes and maintains sleep in men with primary insomnia. SLEEP 2012;35(8):1097-1104. PMID:22851805

Synergistic Effects of Human Milk Nutrients in the Support of Infant Recognition Memory: An Observational Study

PubMed Central

Cheatham, Carol L.; Sheppard, Kelly Will

2015-01-01

The aim was to explore the relation of human milk lutein; choline; and docosahexaenoic acid (DHA) with recognition memory abilities of six-month-olds. Milk samples obtained three to four months postpartum were analyzed for fatty acids, lutein, and choline. At six months, participants were invited to an electrophysiology session. Recognition memory was tested with a 70–30 oddball paradigm in a high-density 128-lead event-related potential (ERP) paradigm. Complete data were available for 55 participants. Data were averaged at six groupings (Frontal Right; Frontal Central; Frontal Left; Central; Midline; and Parietal) for latency to peak, peak amplitude, and mean amplitude. Difference scores were calculated as familiar minus novel. Final regression models revealed the lutein X free choline interaction was significant for the difference in latency scores at frontal and central areas (p < 0.05 and p < 0.001; respectively). Higher choline levels with higher lutein levels were related to better recognition memory. The DHA X free choline interaction was also significant for the difference in latency scores at frontal, central, and midline areas (p < 0.01; p < 0.001; p < 0.05 respectively). Higher choline with higher DHA was related to better recognition memory. Interactions between human milk nutrients appear important in predicting infant cognition, and there may be a benefit to specific nutrient combinations. PMID:26540073

Synergistic Effects of Human Milk Nutrients in the Support of Infant Recognition Memory: An Observational Study.

PubMed

Cheatham, Carol L; Sheppard, Kelly Will

2015-11-03

The aim was to explore the relation of human milk lutein; choline; and docosahexaenoic acid (DHA) with recognition memory abilities of six-month-olds. Milk samples obtained three to four months postpartum were analyzed for fatty acids, lutein, and choline. At six months, participants were invited to an electrophysiology session. Recognition memory was tested with a 70-30 oddball paradigm in a high-density 128-lead event-related potential (ERP) paradigm. Complete data were available for 55 participants. Data were averaged at six groupings (Frontal Right; Frontal Central; Frontal Left; Central; Midline; and Parietal) for latency to peak, peak amplitude, and mean amplitude. Difference scores were calculated as familiar minus novel. Final regression models revealed the lutein X free choline interaction was significant for the difference in latency scores at frontal and central areas (p < 0.05 and p < 0.001; respectively). Higher choline levels with higher lutein levels were related to better recognition memory. The DHA X free choline interaction was also significant for the difference in latency scores at frontal, central, and midline areas (p < 0.01; p < 0.001; p < 0.05 respectively). Higher choline with higher DHA was related to better recognition memory. Interactions between human milk nutrients appear important in predicting infant cognition, and there may be a benefit to specific nutrient combinations.

Programming with non-heap memory in the real time specification for Java

NASA Technical Reports Server (NTRS)

Bollella, G.; Canham, T.; Carson, V.; Champlin, V.; Dvorak, D.; Giovannoni, B.; Indictor, M.; Meyer, K.; Reinholtz, A.; Murray, K.

2003-01-01

The Real-Time Specification for Java (RTSJ) provides facilities for deterministic, real-time execution in a language that is otherwise subject to variable latencies in memory allocation and garbage collection.

Method and apparatus for faulty memory utilization

DOEpatents

Cher, Chen-Yong; Andrade Costa, Carlos H.; Park, Yoonho; Rosenburg, Bryan S.; Ryu, Kyung D.

2016-04-19

A method for faulty memory utilization in a memory system includes: obtaining information regarding memory health status of at least one memory page in the memory system; determining an error tolerance of the memory page when the information regarding memory health status indicates that a failure is predicted to occur in an area of the memory system affecting the memory page; initiating a migration of data stored in the memory page when it is determined that the data stored in the memory page is non-error-tolerant; notifying at least one application regarding a predicted operating system failure and/or a predicted application failure when it is determined that data stored in the memory page is non-error-tolerant and cannot be migrated; and notifying at least one application regarding the memory failure predicted to occur when it is determined that data stored in the memory page is error-tolerant.

Lexical access and evoked traveling alpha waves.

PubMed

Zauner, Andrea; Gruber, Walter; Himmelstoß, Nicole Alexandra; Lechinger, Julia; Klimesch, Wolfgang

2014-05-01

Retrieval from semantic memory is usually considered within a time window around 300-600ms. Here we suggest that lexical access already occurs at around 100ms. This interpretation is based on the finding that semantically rich and frequent words exhibit a significantly shorter topographical latency difference between the site with the shortest P1 latency (leading site) and that with the longest P1 latency (trailing site). This latency difference can be described in terms of an evoked traveling alpha wave as was already shown in earlier studies. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

MK-801 and memantine act differently on short-term memory tested with different time-intervals in the Morris water maze test.

PubMed

Duda, Weronika; Wesierska, Malgorzata; Ostaszewski, Pawel; Vales, Karel; Nekovarova, Tereza; Stuchlik, Ales

2016-09-15

N-methyl-d-aspartate receptors (NMDARs) play a crucial role in spatial memory formation. In neuropharmacological studies their functioning strongly depends on testing conditions and the dosage of NMDAR antagonists. The aim of this study was to assess the immediate effects of NMDAR block by (+)MK-801 or memantine on short-term allothetic memory. Memory was tested in a working memory version of the Morris water maze test. In our version of the test, rats underwent one day of training with 8 trials, and then three experimental days when rats were injected intraperitoneally with low- 5 (MeL), high - 20 (MeH) mg/kg memantine, 0.1mg/kg MK-801 or 1ml/kg saline (SAL) 30min before testing, for three consecutive days. On each experimental day there was just one acquisition and one test trial, with an inter-trial interval of 5 or 15min. During training the hidden platform was relocated after each trial and during the experiment after each day. The follow-up effect was assessed on day 9. Intact rats improved their spatial memory across the one training day. With a 5min interval MeH rats had longer latency then all rats during retrieval. With a 15min interval the MeH rats presented worse working memory measured as retrieval minus acquisition trial for path than SAL and MeL and for latency than MeL rats. MK-801 rats had longer latency than SAL during retrieval. Thus, the high dose of memantine, contrary to low dose of MK-801 disrupts short-term memory independent on the time interval between acquisition and retrieval. This shows that short-term memory tested in a working memory version of water maze is sensitive to several parameters: i.e., NMDA receptor antagonist type, dosage and the time interval between learning and testing. Copyright © 2016. Published by Elsevier B.V.

Design of a universal logic block for fault-tolerant realization of any logic operation in trapped-ion quantum circuits

NASA Astrophysics Data System (ADS)

Goudarzi, H.; Dousti, M. J.; Shafaei, A.; Pedram, M.

2014-05-01

This paper presents a physical mapping tool for quantum circuits, which generates the optimal universal logic block (ULB) that can, on average, perform any logical fault-tolerant (FT) quantum operations with the minimum latency. The operation scheduling, placement, and qubit routing problems tackled by the quantum physical mapper are highly dependent on one another. More precisely, the scheduling solution affects the quality of the achievable placement solution due to resource pressures that may be created as a result of operation scheduling, whereas the operation placement and qubit routing solutions influence the scheduling solution due to resulting distances between predecessor and current operations, which in turn determines routing latencies. The proposed flow for the quantum physical mapper captures these dependencies by applying (1) a loose scheduling step, which transforms an initial quantum data flow graph into one that explicitly captures the no-cloning theorem of the quantum computing and then performs instruction scheduling based on a modified force-directed scheduling approach to minimize the resource contention and quantum circuit latency, (2) a placement step, which uses timing-driven instruction placement to minimize the approximate routing latencies while making iterative calls to the aforesaid force-directed scheduler to correct scheduling levels of quantum operations as needed, and (3) a routing step that finds dynamic values of routing latencies for the qubits. In addition to the quantum physical mapper, an approach is presented to determine the single best ULB size for a target quantum circuit by examining the latency of different FT quantum operations mapped onto different ULB sizes and using information about the occurrence frequency of operations on critical paths of the target quantum algorithm to weigh these latencies. Experimental results show an average latency reduction of about 40 % compared to previous work.

Arousal Enhanced Memory Retention Is Eliminated Following Temporal Lobe Resection

ERIC Educational Resources Information Center

Ahs, Fredrik; Kumlien, Eva; Fredrikson, Mats

2010-01-01

The amygdala, situated in the anterior medial temporal lobe (MTL), is involved in the emotional enhancement of memory. The present study evaluated whether anterior MTL-resections attenuated arousal induced memory enhancement for pictures. Also, the effect of MTL-resections on response latencies at retrieval was assessed. Thirty-one patients with…

Cache write generate for parallel image processing on shared memory architectures.

PubMed

Wittenbrink, C M; Somani, A K; Chen, C H

1996-01-01

We investigate cache write generate, our cache mode invention. We demonstrate that for parallel image processing applications, the new mode improves main memory bandwidth, CPU efficiency, cache hits, and cache latency. We use register level simulations validated by the UW-Proteus system. Many memory, cache, and processor configurations are evaluated.

Investigation of Neuropsychopharmacological Effects of a Polyherbal Formulation on the Learning and Memory Process in Rats

PubMed Central

Shah, JS; Goyal, RK

2011-01-01

Objective: To investigate the neuropsychopharmacological effect of a polyherbal formulation (PHF) on the learning and memory processes in rats. Materials and Methods: PHF contains Withania somnifera (Ashwagandha), Nardostachys jatamansi (Jatamansi), Rauwolfia serpentina (Sarpagandha), Evolvulus alsinoides (Shankhpushpi), Asparagus racemosus (Shatavari), Emblica officinalis (Amalki), Mucuna pruriens (Kauch bij extract), Hyoscyamus niger (Khurasani Ajmo), Mineral resin (Shilajit), Pearl (Mukta Shukhti Pishti), and coral calcium (Praval pishti). Its effect (500 mg / kg, p.o.) on the learning and memory processes was tested. The activity of PHF on memory acquisition and retention was studied using passive avoidance learning and elevated plus maze model (EPM) in rats. Results: The animals treated with PHF showed a significant decrease in transfer latency as compared to the control group in EPM. PHF also produced significant improvement in passive avoidance acquisition and memory retrieval, as compared to the controls and reduced the latency to reach the shock free zone (SFZ) after 24 hours. Conclusion: The PHF produces significant improvement in passive avoidance acquisition and memory retrieval in rats, which needs further investigation. PMID:21731356

Sequential behavior and its inherent tolerance to memory faults.

NASA Technical Reports Server (NTRS)

Meyer, J. F.

1972-01-01

Representation of a memory fault of a sequential machine M by a function mu on the states of M and the result of the fault by an appropriately determined machine M(mu). Given some sequential behavior B, its inherent tolerance to memory faults can then be measured in terms of the minimum memory redundancy required to realize B with a state-assigned machine having fault tolerance type tau and fault tolerance level t. A behavior having maximum inherent tolerance is exhibited, and it is shown that behaviors of the same size can have different inherent tolerance.

Variation in working memory capacity, fluid intelligence, and episodic recall: a latent variable examination of differences in the dynamics of free recall.

PubMed

Unsworth, Nash

2009-09-01

A latent variable analysis was conducted to examine the nature of individual differences in the dynamics of free recall and cognitive abilities. Participants performed multiple measures of free recall, working memory capacity (WMC), and fluid intelligence (gF). For each free recall task, recall accuracy, recall latency, and number of intrusion errors were determined, and latent factors were derived for each. It was found that recall accuracy was negatively related to both recall latency and number of intrusions, and recall latency and number of intrusions were positively related. Furthermore, latent WMC and gF factors were positively related to recall accuracy, but negatively related to recall latency and number of intrusions. Finally, a cluster analysis revealed that subgroups of participants with deficits in focusing the search had deficits in recovering degraded representations or deficits in monitoring the products of retrieval. The results are consistent with the idea that variation in the dynamics of free recall, WMC, and gF are primarily due to differences in search set size, but differences in recovery and monitoring are also important.

Working memory effects of gap-predictions in normal adults: an event-related potentials study.

PubMed

Hestvik, Arild; Bradley, Evan; Bradley, Catherine

2012-12-01

The current study examined the relationship between verbal memory span and the latency with which a filler-gap dependency is constructed. A previous behavioral study found that low span listeners did not exhibit antecedent reactivation at gap sites in relative clauses, in comparison to high verbal memory span subjects (Roberts et al. in J Psycholinguist Res 36(2):175-188, 2007), which suggests that low span subjects are delayed at gap filling. This possibility was examined in the current study. Using an event-related potentials paradigm, it was found that low span subjects have an onset latency delay of about 200 ms in brain responses to violations of syntactic expectancies after the gap site, thus providing a time course measure of the delay hypothesized by previous literature.

Low latency memory access and synchronization

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

Blumrich, Matthias A.; Chen, Dong; Coteus, Paul W.

A low latency memory system access is provided in association with a weakly-ordered multiprocessor system. Each processor in the multiprocessor shares resources, and each shared resource has an associated lock within a locking device that provides support for synchronization between the multiple processors in the multiprocessor and the orderly sharing of the resources. A processor only has permission to access a resource when it owns the lock associated with that resource, and an attempt by a processor to own a lock requires only a single load operation, rather than a traditional atomic load followed by store, such that the processormore » only performs a read operation and the hardware locking device performs a subsequent write operation rather than the processor. A simple prefetching for non-contiguous data structures is also disclosed. A memory line is redefined so that in addition to the normal physical memory data, every line includes a pointer that is large enough to point to any other line in the memory, wherein the pointers to determine which memory line to prefetch rather than some other predictive algorithm. This enables hardware to effectively prefetch memory access patterns that are non-contiguous, but repetitive.« less

Low latency memory access and synchronization

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

Blumrich, Matthias A.; Chen, Dong; Coteus, Paul W.

A low latency memory system access is provided in association with a weakly-ordered multiprocessor system. Bach processor in the multiprocessor shares resources, and each shared resource has an associated lock within a locking device that provides support for synchronization between the multiple processors in the multiprocessor and the orderly sharing of the resources. A processor only has permission to access a resource when it owns the lock associated with that resource, and an attempt by a processor to own a lock requires only a single load operation, rather than a traditional atomic load followed by store, such that the processormore » only performs a read operation and the hardware locking device performs a subsequent write operation rather than the processor. A simple prefetching for non-contiguous data structures is also disclosed. A memory line is redefined so that in addition to the normal physical memory data, every line includes a pointer that is large enough to point to any other line in the memory, wherein the pointers to determine which memory line to prefetch rather than some other predictive algorithm. This enables hardware to effectively prefetch memory access patterns that are non-contiguous, but repetitive.« less

Posttraining intraamygdala infusions of oxotremorine and propranolol modulate storage of memory for reductions in reward magnitude.

PubMed

Salinas, J A; Introini-Collison, I B; Dalmaz, C; McGaugh, J L

1997-07-01

These experiments examined the effects of posttraining intraamygdala administration of the muscarinic agonist, oxotremorine, and the beta-noradrenergic antagonist, propranolol, on memory for reduction in reward magnitude. Male Sprague-Dawley rats (175-200 g) implanted with bilateral intraamygdala cannulae were food deprived (maintained at 80% of body weight) and trained to run a straight alley (six trials/day) for either ten 45-mg food pellets (high reward) or one 45-mg food pellet (low reward) for 10 days. In Experiment One, the animals in the high-reward group were than shifted to a one-pellet reward and immediately given intraamygdala infusions (0.5 microliter/side) of either oxotremorine (10 ng) or phosphate buffer. Shifted training continued for 4 more days and no further injections were given. Shifted animals given the buffer solution displayed an increase in runway latencies but returned to preshift latencies by the fifth day of shifted training. In contrast, animals given oxotremorine exhibited increased latencies through the fifth day. In Experiment Two, rats were trained as in Experiment. One but immediately following the shift received intraamygdala infusions of oxotremorine (10 ng), propranolol (0.3 microgram), both, or phosphate buffer. Shifted vehicle-injected rats returned to preshift performance by the fifth day of shifted training. Shifted propranolol rats returned to preshift latencies by the third day of shifted training. In contrast, the shifted oxotremorine and the shifted oxotremorine/propranolol rats displayed longer latencies than unshifted controls through 5 days of shifted training. The findings indicate that the muscarinic cholinergic and beta-noradrenergic systems within the amygdala interact in regulating memory and support the view that noradrenergic influences are mediated through cholinergic activation.

Non-volatile main memory management methods based on a file system.

PubMed

Oikawa, Shuichi

2014-01-01

There are upcoming non-volatile (NV) memory technologies that provide byte addressability and high performance. PCM, MRAM, and STT-RAM are such examples. Such NV memory can be used as storage because of its data persistency without power supply while it can be used as main memory because of its high performance that matches up with DRAM. There are a number of researches that investigated its uses for main memory and storage. They were, however, conducted independently. This paper presents the methods that enables the integration of the main memory and file system management for NV memory. Such integration makes NV memory simultaneously utilized as both main memory and storage. The presented methods use a file system as their basis for the NV memory management. We implemented the proposed methods in the Linux kernel, and performed the evaluation on the QEMU system emulator. The evaluation results show that 1) the proposed methods can perform comparably to the existing DRAM memory allocator and significantly better than the page swapping, 2) their performance is affected by the internal data structures of a file system, and 3) the data structures appropriate for traditional hard disk drives do not always work effectively for byte addressable NV memory. We also performed the evaluation of the effects caused by the longer access latency of NV memory by cycle-accurate full-system simulation. The results show that the effect on page allocation cost is limited if the increase of latency is moderate.

Increased degradation of ATP is driven by memory regulatory T cells in kidney transplantation tolerance.

PubMed

Durand, Maxim; Dubois, Florian; Dejou, Cécile; Durand, Eugénie; Danger, Richard; Chesneau, Mélanie; Brosseau, Carole; Guerif, Pierrick; Soulillou, Jean-Paul; Degauque, Nicolas; Eliaou, Jean-François; Giral, Magali; Bonnefoy, Nathalie; Brouard, Sophie

2018-05-01

Regulatory T cells were recently proposed as the central actor in operational tolerance after renal transplantation. Tolerant patients harbor increased FoxP3hi memory Treg frequency and increased demethylation in the Foxp3 Treg-specific demethylated region when compared to stable kidney recipients and exhibit greater memory Treg suppressive capacities and higher expression of the ectonucleotidase CD39. However, in this particular and unique situation the mechanisms of action of Tregs were not identified. Thus, we analyzed the ability of memory Tregs to degrade extracellular ATP in tolerant patients, healthy volunteers, and patients with stable graft function under immunosuppression and determined the role of immunosuppressive drugs on this process. The conserved proportion of memory Tregs leads to the establishment of a pro-tolerogenic balance in operationally tolerant patients. Memory Tregs in tolerant patients display normal capacity to degrade extracellular ATP/ADP. In contrast, memory Tregs from patients with stable graft function do not have this ability. Finally, in vitro, immunosuppressive drugs may favor the lower proportion of memory Tregs in stable patients, but they have no effect on CD39-dependent ATP degradation and do not explain memory Treg lack of extracellular ATP/ADP degradation ability. Thus, intrinsic active regulatory mechanisms may act long after immunosuppressive drug arrest in operationally tolerant patients and may contribute to kidney allograft tolerance via the maintenance of CD39 Treg function. Copyright © 2018 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.

A Gammaherpesvirus Bcl-2 Ortholog Blocks B Cell Receptor-Mediated Apoptosis and Promotes the Survival of Developing B Cells In Vivo

PubMed Central

Coleman, Carrie B.; McGraw, Jennifer E.; Feldman, Emily R.; Roth, Alexa N.; Keyes, Lisa R.; Grau, Katrina R.; Cochran, Stephanie L.; Waldschmidt, Thomas J.; Liang, Chengyu; Forrest, J. Craig; Tibbetts, Scott A.

2014-01-01

Gammaherpesviruses such as Epstein-Barr virus (EBV) and Kaposi's sarcoma-associated herpesvirus (KSHV, HHV-8) establish lifelong latency in their hosts and are associated with the development of several types of malignancies, including a subset of B cell lymphomas. These viruses are thought to co-opt the process of B cell differentiation to latently infect a fraction of circulating memory B cells, resulting in the establishment of a stable latency setpoint. However, little is known about how this infected memory B cell compartment is maintained throughout the life of the host. We have previously demonstrated that immature and transitional B cells are long-term latency reservoirs for murine gammaherpesvirus 68 (MHV68), suggesting that infection of developing B cells contributes to the maintenance of lifelong latency. During hematopoiesis, immature and transitional B cells are subject to B cell receptor (BCR)-mediated negative selection, which results in the clonal deletion of autoreactive B cells. Interestingly, numerous gammaherpesviruses encode homologs of the anti-apoptotic protein Bcl-2, suggesting that virus inhibition of apoptosis could subvert clonal deletion. To test this, we quantified latency establishment in mice inoculated with MHV68 vBcl-2 mutants. vBcl-2 mutant viruses displayed a marked decrease in the frequency of immature and transitional B cells harboring viral genome, but this attenuation could be rescued by increased host Bcl-2 expression. Conversely, vBcl-2 mutant virus latency in early B cells and mature B cells, which are not targets of negative selection, was remarkably similar to wild-type virus. Finally, in vivo depletion of developing B cells during chronic infection resulted in decreased mature B cell latency, demonstrating a key role for developing B cells in the maintenance of lifelong latency. Collectively, these findings support a model in which gammaherpesvirus latency in circulating mature B cells is sustained in part through the recurrent infection and vBcl-2-mediated survival of developing B cells. PMID:24516386

7-Nitroindazole, a neuronal nitric oxide synthase inhibitor, impairs passive-avoidance and elevated plus-maze memory performance in rats.

PubMed

Yildiz Akar, Furuzan; Ulak, Guner; Tanyeri, Pelin; Erden, Faruk; Utkan, Tijen; Gacar, Nejat

2007-10-01

The role of nitric oxide (NO) on cognitive performance in a modified elevated plus-maze (mEPM) and passive-avoidance (PA) task was investigated by using the NO synthase (NOS) inhibitor 7-nitroindazole (7-NI) and an NO precursor l-arginine. The interaction between the activation of N-methyl-d-aspartate (NMDA) receptors and NO synthesis on memory retention was also studied. 7-NI, l-arginine or MK-801, a non-competitive NMDA receptor antagonist were injected intraperitoneally (i.p) to male Wistar rats 30 min before the first training session of the PA test or 30 min before on the first day testing (acquisition session) of mEPM task. Transfer latency, the time rat took to move from the open arm to the enclosed arm, was used as an index of learning and memory in a mEPM test. The retention session was performed 24 h after the acquisition one. In the PA task, the retention test was carried out 24 h after training and reduction of retention latency was used to evaluate the acquisition of learning and memory. Blood glucose level and locomotor activity of the rats was also evaluated. 7-NI (10, 20, 25, 50 mg/kg) and MK-801 (0.15 mg/kg) significantly prolonged the transfer latency on retention session in a mEPM test and shortened step-through latency in PA test. 7-NI-induced impairment in memory and learning was partly reversed by l-arginine (200 mg/kg), a competitive substrate for NOS. However subeffective doses of 7-NI (5 mg/kg) and MK-801 (0.075 mg/kg) given in combination significantly impaired plus-maze and PA performances in rats. Thus NMDA receptor mediated NO pathways may be implicated in the PA and mEPM behaviours in rats. Since 7-NI does not affect blood pressure and did not alter blood glucose level and locomotor activity in conscious rats, 7-NI-induced impairment of memory is not due to either hypertension, changes in blood glucose level or effects on locomotor activity.

Cost aware cache replacement policy in shared last-level cache for hybrid memory based fog computing

NASA Astrophysics Data System (ADS)

Jia, Gangyong; Han, Guangjie; Wang, Hao; Wang, Feng

2018-04-01

Fog computing requires a large main memory capacity to decrease latency and increase the Quality of Service (QoS). However, dynamic random access memory (DRAM), the commonly used random access memory, cannot be included into a fog computing system due to its high consumption of power. In recent years, non-volatile memories (NVM) such as Phase-Change Memory (PCM) and Spin-transfer torque RAM (STT-RAM) with their low power consumption have emerged to replace DRAM. Moreover, the currently proposed hybrid main memory, consisting of both DRAM and NVM, have shown promising advantages in terms of scalability and power consumption. However, the drawbacks of NVM, such as long read/write latency give rise to potential problems leading to asymmetric cache misses in the hybrid main memory. Current last level cache (LLC) policies are based on the unified miss cost, and result in poor performance in LLC and add to the cost of using NVM. In order to minimize the cache miss cost in the hybrid main memory, we propose a cost aware cache replacement policy (CACRP) that reduces the number of cache misses from NVM and improves the cache performance for a hybrid memory system. Experimental results show that our CACRP behaves better in LLC performance, improving performance up to 43.6% (15.5% on average) compared to LRU.

CHARACTER OF THE CHANGES IN FEAR MOTIVATED DECLARATIVE MEMORY IN THE HIGH IMMOBILIZATION "DEPRESSIVE" RATS.

PubMed

Nachkebia, N; Shavgulidze, M; Babilodze, M; Chkhartishvili, E; Rogava, N

2016-10-01

Present study investigated possible differences in the learning and memory of declarative memory task in rats selected according to the differences in immobilization response that is in high immobilization "depressive" and low immobilization "non-depressive" rats. Understanding the character of learning and memory disturbances in basal conditions of animal models of depression is still very topical for more intimate definition of the pathophysiology of major depressive disorder and appropriate searching the ways of its correction. Experiments were carried out on the adult white wild rats (with the weight 200-250 g, n=20). Selection of rats according to the level of immobilization was made by means of forced swim test. Learning and memory disturbances were studied using passive avoidance test that is fear motivated one trial declarative memory task. It was shown by us that 100% of low immobilization "non-depressive" rats remember painful stimulation and therefore they are not enter in the dark compartment during whole period of observation during testing session. Behavior of high immobilization "depressive" rats is not similar in passive avoidance camera; 50% of "depressive" rats, with long escape latency during training session (92±10 sec), remember painful stimulation during testing session and therefore they are not enter in the dark compartment during whole observation period. The remaining 50%, that are not differ significantly from the low immobility "non-depressive" rats by the latency of escape (5±1 sec) during training session, are not able to remember painful stimulation during testing session and therefore they enter in the dark compartment with shortest escape latency (6±1 sec). In conclusion, high immobility "depressive" rats perform passive avoidance declarative memory task at the chance level that is a direct indicator for the serious disturbances of declarative memory mechanisms in "depressive" rats selected in forced swim test according to the level of immobility.

p-Coumaric acid enhances long-term potentiation and recovers scopolamine-induced learning and memory impairments.

PubMed

Kim, Hyun-Bum; Lee, Seok; Hwang, Eun-Sang; Maeng, Sungho; Park, Ji-Ho

2017-10-21

Due to the improvement of medical level, life expectancy increased. But the increased incidence of cognitive disorders is an emerging social problem. Current drugs for dementia treatment can only delay the progress rather than cure. p-Coumaric acid is a phenylpropanoic acid derived from aromatic amino acids and known as a precursor for flavonoids such as resveratrol and naringenin. It was shown to reduce oxidative stress, inhibit genotoxicity and exert neuroprotection. Based on these findings, we evaluated whether p-coumaric acid can protect scopolamine induced learning and memory impairment by measuring LTP in organotypic hippocampal slice and cognitive behaviors in rats. p-Coumaric acid dose-dependently increased the total activity of fEPSP after high frequency stimulation and attenuated scopolamine-induced blockade of fEPSP in the hippocampal CA1 area. In addition, while scopolamine shortened the step-through latency in the passive avoidance test and prolonged the latency as well as reduced the latency in the target quadrant in the Morris water maze test, co-treatment of p-coumaric acid improved avoidance memory and long-term retention of spatial memory in behavioral tests. Since p-coumaric acid improved electrophysiological and cognitive functional deterioration by scopolamine, it may have regulatory effects on central cholinergic synapses and is expected to improve cognitive problems caused by abnormality of the cholinergic nervous system. Copyright © 2017 Elsevier Inc. All rights reserved.

Evaluation of Bacopa monniera for its synergistic activity with rivastigmine in reversing aluminum-induced memory loss and learning deficit in rats.

PubMed

Thippeswamy, Agadi Hiremath; Rafiq, Mohamed; Viswantha, Gollapalle Lakshminarayana Shastry; Kavya, Kethaganahalli J; Anturlikar, Suryakanth D; Patki, Pralhad S

2013-08-01

The objective of this study was to evaluate the synergistic activity of Bacopa monniera with Rivastigmine against aluminum-chloride (AlCl3)-induced cognitive impairment in rats. Adult male Wistar rats were divided into ten groups (n = 10) and subjected to their assigned treatments for 42 days. On the 20(th) day of the respective drug treatments, all the animals were trained in the Morris water maze (retention latency) and the elevated plus maze (transfer latency). After the initial training, the retention latency (RL) and the transfer latency (TL) were evaluated on the 21(st) and the 42(nd) days of the study. Chronic administration of AlCl3 caused significant memory impairment associated with increased RL in the Morris water maze task and increased TL in the elevated plus maze test. Interestingly, animals treated with oral administration of B. monniera (100 and 200 mg/kg), Rivastigmine (5 mg/kg) or a combination of B. monniera (100 mg/kg) with Rivastigmine (5 mg/kg) showed significant protection against AlCl3-induced memory impairment compared to animal treated with AlCl3per se. Additionally, the neuroprotective effect of B. monniera (100 and 200 mg/kg) was significantly improved when supplemented with Rivastigmine (5 mg/kg). These findings suggest that treatment with a combination of B. monniera with Rivastigmine may be highly beneficial compared to their per-se treatment. Copyright © 2013. Published by Elsevier B.V.

Effects of diphenhydramine on human eye movements.

PubMed

Hopfenbeck, J R; Cowley, D S; Radant, A; Greenblatt, D J; Roy-Byrne, P P

1995-04-01

Peak saccadic eye movement velocity (SEV) and average smooth pursuit gain (SP) are reduced in a dose-dependent manner by diazepam and provide reliable, quantitative measures of benzodiazepine agonist effects. To evaluate the specificity of these eye movement effects for agents acting at the central GABA-benzodiazepine receptor complex and the role of sedation in benzodiazepine effects, we studied eye movement effects of diphenhydramine, a sedating drug which does not act at the GABA-benzodiazepine receptor complex. Ten healthy males, aged 19-28 years, with no history of axis I psychiatric disorders or substance abuse, received 50 mg/70 kg intravenous diphenhydramine or a similar volume of saline on separate days 1 week apart. SEV, saccade latency and accuracy, SP, self-rated sedation, and short-term memory were assessed at baseline and at 5, 15, 30, 45, 60, 90 and 120 min after drug administration. Compared with placebo, diphenhydramine produced significant SEV slowing, and increases in saccade latency and self-rated sedation. There was no significant effect of diphenhydramine on smooth pursuit gain, saccade accuracy, or short-term memory. These results suggest that, like diazepam, diphenhydramine causes sedation, SEV slowing, and an increase in saccade latency. Since the degree of diphenhydramine-induced sedation was not correlated with changes in SEV or saccade latency, slowing of saccadic eye movements is unlikely to be attributable to sedation alone. Unlike diazepam, diphenhydramine does not impair smooth pursuit gain, saccadic accuracy, or memory. Different neurotransmitter systems may influence the neural pathways involved in SEV and smooth pursuit again.

DEPEND: A simulation-based environment for system level dependability analysis

NASA Technical Reports Server (NTRS)

Goswami, Kumar; Iyer, Ravishankar K.

1992-01-01

The design and evaluation of highly reliable computer systems is a complex issue. Designers mostly develop such systems based on prior knowledge and experience and occasionally from analytical evaluations of simplified designs. A simulation-based environment called DEPEND which is especially geared for the design and evaluation of fault-tolerant architectures is presented. DEPEND is unique in that it exploits the properties of object-oriented programming to provide a flexible framework with which a user can rapidly model and evaluate various fault-tolerant systems. The key features of the DEPEND environment are described, and its capabilities are illustrated with a detailed analysis of a real design. In particular, DEPEND is used to simulate the Unix based Tandem Integrity fault-tolerance and evaluate how well it handles near-coincident errors caused by correlated and latent faults. Issues such as memory scrubbing, re-integration policies, and workload dependent repair times which affect how the system handles near-coincident errors are also evaluated. Issues such as the method used by DEPEND to simulate error latency and the time acceleration technique that provides enormous simulation speed up are also discussed. Unlike any other simulation-based dependability studies, the use of these approaches and the accuracy of the simulation model are validated by comparing the results of the simulations, with measurements obtained from fault injection experiments conducted on a production Tandem Integrity machine.

Working Memory Effects of Gap-Predictions in Normal Adults: An Event-Related Potentials Study

ERIC Educational Resources Information Center

Hestvik, Arild; Bradley, Evan; Bradley, Catherine

2012-01-01

The current study examined the relationship between verbal memory span and the latency with which a filler-gap dependency is constructed. A previous behavioral study found that low span listeners did not exhibit antecedent reactivation at gap sites in relative clauses, in comparison to high verbal memory span subjects (Roberts et al. in "J…

Focusing the search: proactive and retroactive interference and the dynamics of free recall.

PubMed

Unsworth, Nash; Brewer, Gene A; Spillers, Gregory J

2013-11-01

Targeting information in long-term memory is an important cognitive ability, but one that is not well understood. In this study, 4 experiments were conducted to examine the influence of proactive and retroactive interference on memory targeting. Participants were given either 1 or 2 lists and asked to recall List 1, List 2, or in some cases both lists. Multiple dependent measures were explored including the proportion of items recalled, number of intrusions output, and recall latency to arbitrate between 4 extant accounts of memory targeting. In general, recalling either List 1 or List 2 resulted in lower probability of recall, recall of more intrusions, and longer recall latencies compared to when recalling a list alone, suggesting both proactive and retroactive interference. These results suggest that long-term memory targeting is guided by noisy temporal-contextual cues (unless other salient cues are present) that activate both relevant and irrelevant memoranda that are then subjected to a postretrieval monitoring process. PsycINFO Database Record (c) 2013 APA, all rights reserved.

Biflorin Ameliorates Memory Impairments Induced by Cholinergic Blockade in Mice

PubMed Central

Jeon, Se Jin; Kim, Boseong; Ryu, Byeol; Kim, Eunji; Lee, Sunhee; Jang, Dae Sik; Ryu, Jong Hoon

2017-01-01

To examine the effect of biflorin, a component of Syzygium aromaticum, on memory deficit, we introduced a scopolamine-induced cognitive deficit mouse model. A single administration of biflorin increased latency time in the passive avoidance task, ameliorated alternation behavior in the Y-maze, and increased exploration time in the Morris water maze task, indicating the improvement of cognitive behaviors against cholinergic dysfunction. The biflorin-induced reverse of latency in the scopolamine-treated group was attenuated by MK-801, an NMDA receptor antagonist. Biflorin also enhanced cognitive function in a naïve mouse model. To understand the mechanism of biflorin for memory amelioration, we performed Western blot. Biflorin increased the activation of protein kinase C-ζ and its downstream signaling molecules in the hippocampus. These results suggest that biflorin ameliorates drug-induced memory impairment by modulation of protein kinase C-ζ signaling in mice, implying that biflorin could function as a possible therapeutic agent for the treatment of cognitive problems. PMID:27829270

Visual working memory is more tolerant than visual long-term memory.

PubMed

Schurgin, Mark W; Flombaum, Jonathan I

2018-05-07

Human visual memory is tolerant, meaning that it supports object recognition despite variability across encounters at the image level. Tolerant object recognition remains one capacity in which artificial intelligence trails humans. Typically, tolerance is described as a property of human visual long-term memory (VLTM). In contrast, visual working memory (VWM) is not usually ascribed a role in tolerant recognition, with tests of that system usually demanding discriminatory power-identifying changes, not sameness. There are good reasons to expect that VLTM is more tolerant; functionally, recognition over the long-term must accommodate the fact that objects will not be viewed under identical conditions; and practically, the passive and massive nature of VLTM may impose relatively permissive criteria for thinking that two inputs are the same. But empirically, tolerance has never been compared across working and long-term visual memory. We therefore developed a novel paradigm for equating encoding and test across different memory types. In each experiment trial, participants saw two objects, memory for one tested immediately (VWM) and later for the other (VLTM). VWM performance was better than VLTM and remained robust despite the introduction of image and object variability. In contrast, VLTM performance suffered linearly as more variability was introduced into test stimuli. Additional experiments excluded interference effects as causes for the observed differences. These results suggest the possibility of a previously unidentified role for VWM in the acquisition of tolerant representations for object recognition. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

A Novel Persistence Associated EBV miRNA Expression Profile Is Disrupted in Neoplasia

PubMed Central

Qiu, Jin; Cosmopoulos, Katherine; Pegtel, Michiel; Hopmans, Erik; Murray, Paul; Middeldorp, Jaap; Shapiro, Michael; Thorley-Lawson, David A.

2011-01-01

We have performed the first extensive profiling of Epstein-Barr virus (EBV) miRNAs on in vivo derived normal and neoplastic infected tissues. We describe a unique pattern of viral miRNA expression by normal infected cells in vivo expressing restricted viral latency programs (germinal center: Latency II and memory B: Latency I/0). This includes the complete absence of 15 of the 34 miRNAs profiled. These consist of 12 BART miRNAs (including approximately half of Cluster 2) and 3 of the 4 BHRF1 miRNAs. All but 2 of these absent miRNAs become expressed during EBV driven growth (Latency III). Furthermore, EBV driven growth is accompanied by a 5–10 fold down regulation in the level of the BART miRNAs expressed in germinal center and memory B cells. Therefore, Latency III also expresses a unique pattern of viral miRNAs. We refer to the miRNAs that are specifically expressed in EBV driven growth as the Latency III associated miRNAs. In EBV associated tumors that employ Latency I or II (Burkitt's lymphoma, Hodgkin's disease, nasopharyngeal carcinoma and gastric carcinoma), the Latency III associated BART but not BHRF1 miRNAs are up regulated. Thus BART miRNA expression is deregulated in the EBV associated tumors. This is the first demonstration that Latency III specific genes (the Latency III associated BARTs) can be expressed in these tumors. The EBV associated tumors demonstrate very similar patterns of miRNA expression yet were readily distinguished when the expression data were analyzed either by heat-map/clustering or principal component analysis. Systematic analysis revealed that the information distinguishing the tumor types was redundant and distributed across all the miRNAs. This resembles “secret sharing” algorithms where information can be distributed among a large number of recipients in such a way that any combination of a small number of recipients is able to understand the message. Biologically, this may be a consequence of functional redundancy between the miRNAs. PMID:21901094

Measurement-based analysis of error latency. [in computer operating system

NASA Technical Reports Server (NTRS)

Chillarege, Ram; Iyer, Ravishankar K.

1987-01-01

This paper demonstrates a practical methodology for the study of error latency under a real workload. The method is illustrated with sampled data on the physical memory activity, gathered by hardware instrumentation on a VAX 11/780 during the normal workload cycle of the installation. These data are used to simulate fault occurrence and to reconstruct the error discovery process in the system. The technique provides a means to study the system under different workloads and for multiple days. An approach to determine the percentage of undiscovered errors is also developed and a verification of the entire methodology is performed. This study finds that the mean error latency, in the memory containing the operating system, varies by a factor of 10 to 1 (in hours) between the low and high workloads. It is found that of all errors occurring within a day, 70 percent are detected in the same day, 82 percent within the following day, and 91 percent within the third day. The increase in failure rate due to latency is not so much a function of remaining errors but is dependent on whether or not there is a latent error.

HyspIRI Low Latency Concept and Benchmarks

NASA Technical Reports Server (NTRS)

Mandl, Dan

2010-01-01

Topics include HyspIRI low latency data ops concept, HyspIRI data flow, ongoing efforts, experiment with Web Coverage Processing Service (WCPS) approach to injecting new algorithms into SensorWeb, low fidelity HyspIRI IPM testbed, compute cloud testbed, open cloud testbed environment, Global Lambda Integrated Facility (GLIF) and OCC collaboration with Starlight, delay tolerant network (DTN) protocol benchmarking, and EO-1 configuration for preliminary DTN prototype.

Time Frame Affects Vantage Point in Episodic and Semantic Autobiographical Memory: Evidence from Response Latencies

PubMed Central

Karylowski, Jerzy J.; Mrozinski, Blazej

2017-01-01

Previous research suggests that, with the passage of time, representations of self in episodic memory become less dependent on their initial (internal) vantage point and shift toward an external perspective that is normally characteristic of how other people are represented. The present experiment examined this phenomenon in both episodic and semantic autobiographical memory using latency of self-judgments as a measure of accessibility of the internal vs. the external perspective. Results confirmed that in the case of representations of the self retrieved from recent autobiographical memories, trait-judgments regarding unobservable self-aspects (internal perspective) were faster than trait judgments regarding observable self-aspects (external perspective). Yet, in the case of self-representations retrieved from memories of a more distant past, judgments regarding observable self-aspects were faster. Those results occurred for both self-representations retrieved from episodic memory and for representations retrieved from the semantic memory. In addition, regardless of the effect of time, greater accessibility of unobservable (vs. observable) self-aspects was associated with the episodic rather than semantic autobiographical memory. Those results were modified by neither declared trait’s self-descriptiveness (yes vs. no responses) nor by its desirability (highly desirable vs. moderately desirable traits). Implications for compatibility between how self and others are represented and for the role of self in social perception are discussed. PMID:28473793

Time Frame Affects Vantage Point in Episodic and Semantic Autobiographical Memory: Evidence from Response Latencies.

PubMed

Karylowski, Jerzy J; Mrozinski, Blazej

2017-01-01

Previous research suggests that, with the passage of time, representations of self in episodic memory become less dependent on their initial (internal) vantage point and shift toward an external perspective that is normally characteristic of how other people are represented. The present experiment examined this phenomenon in both episodic and semantic autobiographical memory using latency of self-judgments as a measure of accessibility of the internal vs. the external perspective. Results confirmed that in the case of representations of the self retrieved from recent autobiographical memories, trait-judgments regarding unobservable self-aspects (internal perspective) were faster than trait judgments regarding observable self-aspects (external perspective). Yet, in the case of self-representations retrieved from memories of a more distant past, judgments regarding observable self-aspects were faster. Those results occurred for both self-representations retrieved from episodic memory and for representations retrieved from the semantic memory. In addition, regardless of the effect of time, greater accessibility of unobservable (vs. observable) self-aspects was associated with the episodic rather than semantic autobiographical memory. Those results were modified by neither declared trait's self-descriptiveness ( yes vs. no responses) nor by its desirability (highly desirable vs. moderately desirable traits). Implications for compatibility between how self and others are represented and for the role of self in social perception are discussed.

Recall Latencies, Confidence, and Output Positions of True and False Memories: Implications for Recall and Metamemory Theories

ERIC Educational Resources Information Center

Jou, Jerwen

2008-01-01

Recall latency, recall accuracy rate, and recall confidence were examined in free recall as a function of recall output serial position using a modified Deese-Roediger-McDermott paradigm to test a strength-based theory against the dual-retrieval process theory of recall output sequence. The strength theory predicts the item output sequence to be…

Visual Evoked Potential to Assess Retinopathy in Gestational Diabetes Mellitus.

PubMed

Hari Kumar, K V S; Ahmad, F M H; Sood, Sandeep; Mansingh, Sudhir

2016-04-01

We evaluated for early retinopathy using the visual evoked potential (VEP) in patients with gestational diabetes mellitus (GDM) and type 2 diabetes mellitus during pregnancy. All patients with GDM and type 2 diabetes seen between June and October of 2014 were included in this cross-sectional, observational study. Patients with secondary diabetes, ocular or major illness were excluded from the study. VEP was recorded in both eyes to derive prominent positive peak latency (P100), amplitude and initial negative deflection (N75) latency. The data were compared with 10 gestational age-matched controls with normal glucose tolerance. Appropriate statistical methods were used for comparison among the 3 groups. The study participants (40 with GDM, 10 with type 2 diabetes, 10 with normal glucose tolerance) had a median (25th to 75th interquartile range) age of 26 (24.3, 30) years, a gestational age of 24.5 (21, 27) weeks and weights of 66.8 (63.4, 71.5) kg. The P100 latencies were comparable among the 3 groups (p=0.0577). However, patients with any diabetes (GDM and type 2 diabetes) had prolonged P100 latencies (p=0.0139) and low P100 amplitudes (p=0.0391) in comparison to controls. P100 latency showed a direct correlation with hyperglycemia (p=0.0118). Our data showed that VEP abnormalities are detectable even in the short-term hyperglycemia of GDM and type 2 diabetes. Copyright © 2016 Canadian Diabetes Association. Published by Elsevier Inc. All rights reserved.

Effect of Armodafinil on Cortical Activity and Working Memory in Patients with Residual Excessive Sleepiness Associated with CPAP-Treated OSA: A Multicenter fMRI Study

PubMed Central

Greve, Douglas N.; Duntley, Stephen P.; Larson-Prior, Linda; Krystal, Andrew D.; Diaz, Michele T.; Drummond, Sean P. A.; Thein, Stephen G.; Kushida, Clete A.; Yang, Ronghua; Thomas, Robert J.

2014-01-01

Study Objective: To assess the effect of armodafinil on task-related prefrontal cortex activation using functional magnetic resonance imaging (fMRI) in patients with obstructive sleep apnea (OSA) and excessive sleepiness despite continuous positive airway pressure (CPAP) therapy. Methods: This 2-week, multicenter, prospective, randomized, double-blind, placebo-controlled, parallel-group study was conducted at five neuroimaging sites and four collaborating clinical study centers in the United States. Patients were 40 right-handed or ambidextrous men and women aged between 18 and 60 years, with OSA and persistent sleepiness, as determined by multiple sleep latency and Epworth Sleepiness Scale scores, despite effective, stable use of CPAP. Treatment was randomized (1:1) to once-daily armodafinil 200 mg or placebo. The primary efficacy outcome was a change from baseline at week 2 in the volume of activation meeting the predefined threshold in the dorsolateral prefrontal cortex during a 2-back working memory task. The key secondary measure was the change in task response latency. Results: No significant differences were observed between treatment groups in the primary or key secondary outcomes. Armodafinil was generally well tolerated. The most common adverse events (occurring in more than one patient [5%]) were headache (19%), nasopharyngitis (14%), and diarrhea (10%). Conclusions: Armodafinil did not improve fMRI-measured functional brain activation in CPAP-treated patients with OSA and excessive sleepiness. Study Registration: Double-Blind, Placebo-Controlled, Functional Neuroimaging Study of Armodafinil (200 mg/Day) on Prefrontal Cortical Activation in Patients With Residual Excessive Sleepiness Associated With Obstructive Sleep Apnea/Hypopnea. ClinicalTrials.gov Identifier: NCT00711516. http://www.clinicaltrials.gov/ct2/show/study/NCT00711516 Citation: Greve DN; Duntley SP; Larson-Prior L; Krystal AD; Diaz MT; Drummond SP; Thein SG; Kushida CA; Yang R; Thomas RJ. Effect of armodafinil on cortical activity and working memory in patients with residual excessive sleepiness associated with CPAP-treated OSA: a multicenter fMRI study. J Clin Sleep Med 2014;10(2):143-153. PMID:24532997

Regulation and dysregulation of Epstein-Barr virus latency: implications for the development of autoimmune diseases.

PubMed

Niller, Hans Helmut; Wolf, Hans; Minarovits, Janos

2008-05-01

Epstein-Barr virus (EBV) is a human herpesvirus hiding in a latent form in memory B cells in the majority of the world population. Although, primary EBV infection is asymptomatic or causes a self-limiting disease, infectious mononucleosis, the virus is associated with a wide variety of neoplasms developing in immunosuppressed or immunodeficient individuals, but also in patients with an apparently intact immune system. In memory B cells, tumor cells, and lymphoblastoid cell lines (LCLs, transformed by EBV in vitro) the expression of the viral genes is highly restricted. There is no virus production (lytic viral replication associated with the expression of all viral genes) in tight latency. The expression of latent viral oncogenes and RNAs is under a strict epigenetic control via DNA methylation and histone modifications that results either in a complete silencing of the EBV genome in memory B cells, or in a cell-type dependent usage of latent promoters in tumor cells, germinal center B cells, and LCLs. Both the latent and lytic EBV proteins are potent immunogens and elicit vigorous B- and T-cell responses. In immunosuppressed and immunodeficient patients, or in individuals with a functional defect of EBV-specific T cells, lytic EBV replication is regularly activated and an increased viral load can be detected in the blood. Enhanced lytic replication results in new infection events and EBV-associated transformation events, and seems to be a risk factor both for malignant transformation and the development of autoimmune diseases. One may speculate that an increased load or altered presentation of a limited set of lytic or latent EBV proteins that cross-react with cellular antigens triggers and perpetuates the pathogenic processes that result in multiple sclerosis, systemic lupus erythematosus (SLE), and rheumatoid arthritis. In addition, in SLE patients EBV may cause defects of B-cell tolerance checkpoints because latent membrane protein 1, an EBV-encoded viral oncoprotein can induce BAFF, a B-cell activating factor that rescues self-reactive B cells and induces a lupus-like autoimmune disease in transgenic mice.

Future Development of Dense Ferroelectric Memories for Space Applications

NASA Technical Reports Server (NTRS)

Philpy, Stephen C.; Derbenwick, Gary F.

2001-01-01

The availability of high density, radiation tolerant, nonvolatile memories is critical for space applications. Ferroelectric memories, when fabricated with radiation hardened complementary metal oxide semiconductors (CMOS), can be manufactured and packaged to provide high density replacements for Flash memory, which is not radiation tolerant. Previous work showed ferroelectric memory cells to be resistant to single event upsets and proton irradiation, and ferroelectric storage capacitors to be resistant to neutron exposure. In addition to radiation hardness, the fast programming times, virtually unlimited endurance, and low voltage, low power operation make ferroelectric memories ideal for space missions. Previously, a commercial double level metal 64-kilobit ferroelectric memory was presented. Although the capabilities of radiation hardened wafer fabrication facilities lag behind those of the most modern commercial wafer fabrication facilities, several paths to achieving radiation tolerant, dense ferroelectric memories are emerging. Both short and long term solutions are presented in this paper. Although worldwide major semiconductor companies are introducing commercial ferroelectric memories, funding limitations must be overcome to proceed with the development of high density, radiation tolerant ferroelectric memories.

The evolving roles of memory immune cells in transplantation

PubMed Central

Chen, Wenhao; Ghobrial, Rafik M.; Li, Xian C.

2015-01-01

Memory cells are the products of immune responses but also exert significant impact on subsequent immunity and immune tolerance, thus placing them in a unique position in transplant research. Memory cells are heterogeneous, including not only memory T cells but also memory B cells and innate memory cells. Memory cells are a critical component of protective immunity against invading pathogens, especially in immunosuppressed patients, but they also mediate graft loss and tolerance resistance. Recent studies suggest that some memory cells unexpectedly act as regulatory cells, promoting rather than hindering transplant survival. This functional diversity makes therapeutic targeting of memory cells a challenging task in transplantation. In this article we highlight recent advances in our understanding of memory cells, focusing on diversity of memory cells and mechanisms involved in their induction and functions. We also provide a broad overview on the challenges and opportunities in targeting memory cells in the induction of transplant tolerance. PMID:26102615

Blackcomb: Hardware-Software Co-design for Non-Volatile Memory in Exascale Systems

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

Schreiber, Robert

Summary of technical results of Blackcomb Memory Devices We explored various different memory technologies (STTRAM, PCRAM, FeRAM, and ReRAM). The progress can be classified into three categories, below. Modeling and Tool Releases Various modeling tools have been developed over the last decade to help in the design of SRAM or DRAM-based memory hierarchies. To explore new design opportunities that NVM technologies can bring to the designers, we have developed similar high-level models for NVM, including PCRAMsim [Dong 2009], NVSim [Dong 2012], and NVMain [Poremba 2012]. NVSim is a circuit-level model for NVM performance, energy, and area estimation, which supports variousmore » NVM technologies, including STT-RAM, PCRAM, ReRAM, and legacy NAND Flash. NVSim is successfully validated against industrial NVM prototypes, and it is expected to help boost architecture-level NVM-related studies. On the other side, NVMain is a cycle accurate main memory simulator designed to simulate emerging nonvolatile memories at the architectural level. We have released these models as open source tools and provided contiguous support to them. We also proposed PS3-RAM, which is a fast, portable and scalable statistical STT-RAM reliability analysis model [Wen 2012]. Design Space Exploration and Optimization With the support of these models, we explore different device/circuit optimization techniques. For example, in [Niu 2012a] we studied the power reduction technique for the application of ECC scheme in ReRAM designs and proposed to use ECC code to relax the BER (Bit Error Rate) requirement of a single memory to improve the write energy consumption and latency for both 1T1R and cross-point ReRAM designs. In [Xu 2011], we proposed a methodology to design STT-RAM for different optimization goals such as read performance, write performance and write energy by leveraging the trade-off between write current and write time of MTJ. We also studied the tradeoffs in building a reliable crosspoint ReRAM array [Niu 2012b]. We have conducted an in depth analysis of the circuit and system level design implications of multi-layer cross-point Resistive RAM (MLCReRAM) from performance, power and reliability perspectives [Xu 2013]. The objective of this study is to understand the design trade-offs of this technology with respect to the MLC Phase Change Memory (MLCPCM).Our MLC ReRAM design at the circuit and system levels indicates that different resistance allocation schemes, programming strategies, peripheral designs, and material selections profoundly affect the area, latency, power, and reliability of MLC ReRAM. Based on this analysis, we conduct two case studies: first we compare MLC ReRAM design against MLC phase-change memory (PCM) and multi-layer cross-point ReRAM design, and point out why multi-level ReRAM is appealing; second we further explore the design space for MLC ReRAM. Architecture and Application We explored hybrid checkpointing using phase-change memory for future exascale systems [Dong 2011] and showed that the use of nonvolatile memory for local checkpointing significantly increases the number of faults covered by local checkpoints and reduces the probability of a global failure in the middle of a global checkpoint to less than 1%. We also proposed a technique called i2WAP to mitigate the write variations in NVM-based last-level cache for the improvement of the NVM lifetime [Wang 2013]. Our wear leveling technique attempts to work around the limitations of write endurance by arranging data access so that write operations can be distributed evenly across all the storage cells. During our intensive research on fault-tolerant NVM design, we found that ECC cannot effectively tolerate hard errors from limited write endurance and process imperfection. Therefore, we devised a novel Point and Discard (PAD) architecture in in [ 2012] as a hard-error-tolerant architecture for ReRAM-based Last Level Caches. PAD improves the lifetime of ReRAM caches by 1.6X-440X under different process variations without performance overhead in the system's early life. We have investigated the applicability of NVM for persistent memory design [Zhao 2013]. New byte addressable NVM enables fast persistent memory that allows in-memory persistent data objects to be updated with much higher throughput. Despite the significant improvement, the performance of these designs is only 50% of the native system with no persistence support, due to the logging or copy-on-write mechanisms used to update the persistent memory. A challenge in this approach is therefore how to efficiently enable atomic, consistent, and durable updates to ensure data persistence that survives application and/or system failures. We have designed a persistent memory system, called Klin, that can provide performance as close as that of the native system. The Klin design adopts a non-volatile cache and a non-volatile main memory for constructing a multi-versioned durable memory system, enabling atomic updates without logging or copy-on-write. Our evaluation shows that the proposed Kiln mechanism can achieve up to 2X of performance improvement to NVRAM-based persistent memory employing write-ahead logging. In addition, our design has numerous practical advantages: a simple and intuitive abstract interface, microarchitecture-level optimizations, fast recovery from failures, and no redundant writes to slow non-volatile storage media. The work was published in MICRO 2013 and received Best Paper Honorable Mentioned Award.« less

Learning and memory promoting effects of crude garlic extract.

PubMed

Mukherjee, Dhrubajyoti; Banerjee, Sugato

2013-12-01

Chronic administration of aged garlic extract has been shown to prevent memory impairment in mice. Acute and chronic (21 days) effects of marketed formulation of crude garlic extract (Lasuna) were evaluated on learning and memory in mice using step down latency (SDL) by passive avoidance response and transfer latency (TL) using elevated plus maze. Scopolamine (0.4 mg/kg, ip) was used to induce amnesia in mice and piracetam (200 mg/kg, ip) served as positive control. In the acute study, Lasuna (65 mg/kg, po) partially reversed the scopolamine-induced amnesia but failed to improve learning and memory in untreated animals. Chronic administration of Lasuna (40 mg/kg/day for 21 days) significantly improved learning both in control and scopolamine induced amnesic animals. Influence of Lasuna on central cholinergic activity and its antioxidant properties were also studied by estimating the cortical acetylcholinesterase (AchE) activity and reduced glutathione (GSH) levels respectively. Chronic administration of Lasuna inhibited AchE, while increasing GSH levels. Thus the results indicate that long-term administration of crude garlic extract may improve learning and memory in mice while the underlying mechanism of action may be attributed to the anti-AchE activity and anti-oxidant property of garlic.

The beneficial effects of olibanum on memory deficit induced by hypothyroidism in adult rats tested in Morris water maze.

PubMed

Hosseini, Mahmoud; Hadjzadeh, Mosa Al-Reza; Derakhshan, Mohammad; Havakhah, Shahrzad; Rassouli, Fatemeh Behnam; Rakhshandeh, Hassan; Saffarzadeh, Fatema

2010-03-01

Functional consequences of hypothyroidism include impaired learning and memory and inability to produce long-term potentiation (LTP) in hippocampus. Olibanum has been used for variety of therapeutic purposes. In traditional medicine, oilbanum is used to enhance learning and memory. In the present study the effect of olibanum on memory deficit in hypothyroid rats was investigated. Male wistar rats were divided into four groups and treated for 180 days. Group 1 received tap drinking water while in group 2, 0.03% methimazol was added to drinking water. Group 3 and 4 were treated with 0.03% methimazole as well as 100 and 500 mg/kg olibanum respectively. The animals were tested in Morris water maze. The swimming speed was significantly lower and the distance and time latency were higher in group 2 compared with group 1. In groups 3 and 4 the swimming speed was significantly higher while, the length of the swim path and time latency were significantly lower in comparison with group 2. It is concluded that methimazole-induced hypothyroidism impairs learning and memory in adult rats which could be prevented by using olibanum.

[Effect of lead and selenium on learning and memory ability in rats].

PubMed

Han, Xiaojie; Hu, Xiaoxia; Wei, Qing; Chen, Yilin; Yu, De'e; Hu, Qiansheng

2013-11-01

To study the effect of lead and (or) selenium on learning and memory ability in rats. SPF Wistar rats, after weaning, were divided into six groups, control group, Pb group (respectively Pb exposed), Se group (respectively Se added), Pb-Se group (added Se after Pb exposure), Se-Pb group (added Se before Pb exposure) and Pb + Se group (Pb and Se exposed simultaneously). After intervention for six weeks in rats, the spatial learning and memory of each group rats were measured by Morris water maze assay. Rats in Pb group had significantly longer latency, less site crossings, less percentage of time and distance spent in the target quadrant, and bigger first bearing compared with control group (P < 0.05). Rats in Pb and Se joint exposure groups had significantly shorter latency, more site crossings, less percentage of time and distance spent in the target quadrant, and smaller first bearing compared with Pb group (P < 0.05). There were no significant differences in the indexes of spatial learning and memory ability between the groups of lead and selenium joint exposure groups (P > 0.05). Lead damaged the ability of learning and memory in rats and organic selenium had protective effects on Pb-induced spatial learning and memory deficits in rats.

Depletion of CD8 Memory T Cells for Induction of Tolerance of a Previously Transplanted Kidney Allograft

PubMed Central

Koyama, I.; Nadazdin, O.; Boskovic, S.; Ochiai, T.; Smith, R. N.; Sykes, M.; Sogawa, H.; Murakami, T.; Strom, T. B.; Colvin, R. B.; Sachs, D. H.; Benichou, G.; Cosimi, A. B.; Kawai, T.

2013-01-01

Heterologous immunologic memory has been considered a potent barrier to tolerance induction in primates. Induction of such tolerance for a previously transplanted organ may be more difficult, because specific memory cells can be induced and activated by a transplanted organ. In the current study, we attempted to induce tolerance to a previously transplanted kidney allograft in nonhuman primates. The conditioning regimen consisted of low dose total body irradiation, thymic irradiation, antithymocyte globulin, and anti- CD154 antibody followed by a brief course of a calcineurin inhibitor. This regimen had been shown to induce mixed chimerism and allograft tolerance when kidney transplantation (KTx) and donor bone marrow transplantation (DBMT) were simultaneously performed. However, the same regimen failed to induce mixed chimerism when delayed DBMT was performed after KTx. We found that significant levels of memory T cells remained after conditioning, despite effective depletion of naïve T cells. By adding humanized anti-CD8 monoclonal antibody (cM-T807), CD8 memory T cells were effectively depleted and these recipients successfully achieved mixed chimerism and tolerance. The current studies provide ‘proof of principle’ that the mixed chimerism approach can induce renal allograft tolerance, even late after organ transplantation if memory T-cell function is adequately controlled. PMID:17286617

Measurement and analysis of workload effects on fault latency in real-time systems

NASA Technical Reports Server (NTRS)

Woodbury, Michael H.; Shin, Kang G.

1990-01-01

The authors demonstrate the need to address fault latency in highly reliable real-time control computer systems. It is noted that the effectiveness of all known recovery mechanisms is greatly reduced in the presence of multiple latent faults. The presence of multiple latent faults increases the possibility of multiple errors, which could result in coverage failure. The authors present experimental evidence indicating that the duration of fault latency is dependent on workload. A synthetic workload generator is used to vary the workload, and a hardware fault injector is applied to inject transient faults of varying durations. This method makes it possible to derive the distribution of fault latency duration. Experimental results obtained from the fault-tolerant multiprocessor at the NASA Airlab are presented and discussed.

Modeling Criterion Shifts and Target Checking in Prospective Memory Monitoring

ERIC Educational Resources Information Center

Horn, Sebastian S.; Bayen, Ute J.

2015-01-01

Event-based prospective memory (PM) involves remembering to perform intended actions after a delay. An important theoretical issue is whether and how people monitor the environment to execute an intended action when a target event occurs. Performing a PM task often increases the latencies in ongoing tasks. However, little is known about the…

P300 Latency and the Development of Memory Span.

ERIC Educational Resources Information Center

Howard, Lawrence

The way cognitive, event-related brain potentials (ERPs) can aid in further understanding of memory span change in children is discussed. ERPs are time-dependent changes in electrical activity of the brain (as recorded by scalp electrodes) following the presentation of a physical stimulus through auditory, visual, or somatosensory modalities. The…

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

Gebis, Joseph; Oliker, Leonid; Shalf, John

The disparity between microprocessor clock frequencies and memory latency is a primary reason why many demanding applications run well below peak achievable performance. Software controlled scratchpad memories, such as the Cell local store, attempt to ameliorate this discrepancy by enabling precise control over memory movement; however, scratchpad technology confronts the programmer and compiler with an unfamiliar and difficult programming model. In this work, we present the Virtual Vector Architecture (ViVA), which combines the memory semantics of vector computers with a software-controlled scratchpad memory in order to provide a more effective and practical approach to latency hiding. ViVA requires minimal changesmore » to the core design and could thus be easily integrated with conventional processor cores. To validate our approach, we implemented ViVA on the Mambo cycle-accurate full system simulator, which was carefully calibrated to match the performance on our underlying PowerPC Apple G5 architecture. Results show that ViVA is able to deliver significant performance benefits over scalar techniques for a variety of memory access patterns as well as two important memory-bound compact kernels, corner turn and sparse matrix-vector multiplication -- achieving 2x-13x improvement compared the scalar version. Overall, our preliminary ViVA exploration points to a promising approach for improving application performance on leading microprocessors with minimal design and complexity costs, in a power efficient manner.« less

Modeling and measurement of fault-tolerant multiprocessors

NASA Technical Reports Server (NTRS)

Shin, K. G.; Woodbury, M. H.; Lee, Y. H.

1985-01-01

The workload effects on computer performance are addressed first for a highly reliable unibus multiprocessor used in real-time control. As an approach to studing these effects, a modified Stochastic Petri Net (SPN) is used to describe the synchronous operation of the multiprocessor system. From this model the vital components affecting performance can be determined. However, because of the complexity in solving the modified SPN, a simpler model, i.e., a closed priority queuing network, is constructed that represents the same critical aspects. The use of this model for a specific application requires the partitioning of the workload into job classes. It is shown that the steady state solution of the queuing model directly produces useful results. The use of this model in evaluating an existing system, the Fault Tolerant Multiprocessor (FTMP) at the NASA AIRLAB, is outlined with some experimental results. Also addressed is the technique of measuring fault latency, an important microscopic system parameter. Most related works have assumed no or a negligible fault latency and then performed approximate analyses. To eliminate this deficiency, a new methodology for indirectly measuring fault latency is presented.

[Effect of leptin on long-term spatial memory of rats with white matter damage in developing brain].

PubMed

Feng, Er-Cui; Jiang, Li

2017-12-01

To investigate the neuroprotective effect of leptin by observing its effect on spatial memory of rats with white matter damage in developing brain. A total of 80 neonatal rats were randomly divided into 3 groups: sham-operation (n=27), model (n=27) and leptin intervention (n=27). The rats in the model and leptin intervention groups were used to prepare a model of white matter damage in developing brain, and the rats in the leptin intervention group were given leptin (100 μg/kg) diluted with normal saline immediately after modelling for 4 consecutive days. The survival rate of the rats was observed and the change in body weight was monitored. When the rats reached the age of 21 days, the Morris water maze test was used to evaluate spatial memory. There was no significant difference in the survival rate of rats between the three groups (P>0.05). Within 10 days after birth, the leptin intervention group had similar body weight as the sham-operation group and significantly lower body weight than the model group (P<0.05); more than 10 days after birth, the leptin intervention group had rapid growth with higher body weight than the model and sham-operation groups (P>0.05). The results of place navigation showed that from the second day of experiment, there was a significant difference in the latency period between the three groups (P<0.05); from the fourth day of experiment, the leptin intervention group had a similar latency period as the sham-operation and a significantly shorter latency period than the model group (P<0.05). The results of space search experiment showed that compared with the sham-operation group, the model group had a significant reduction in the number of platform crossings and a significantly longer latency period (P<0.05); compared with the model group, the leptin intervention group had a significantly increased number of platform crossings and a significantly shortened latency period (P<0.05), while there was no significant difference between the leptin intervention and sham-operation groups. Leptin can alleviate spatial memory impairment of rats with white matter damage in developing brain. It thus exerts a neuroprotective effect, and is worthy of further research.

Handling of Adolescent Rats Improves Learning and Memory and Decreases Anxiety

PubMed Central

Costa, Rafaela; Tamascia, Mariana L; Nogueira, Marie D; Casarini, Dulce E; Marcondes, Fernanda K

2012-01-01

Some environmental interventions can result in physiologic and behavioral changes in laboratory animals. In this context, the handling of adolescent or adult rodents has been reported to influence exploratory behavior and emotionality. Here we examined the effects of handling on memory and anxiety levels of adolescent rats. Male Sprague–Dawley rats (age, 60 d) were divided into a control group and a handled group, which were handled for 5 min daily, 5 d per week, for 6 wk. During handling bouts, the rat was removed from its cage, placed in the experimenter's lap or on the top of a table, and had its neck and back gently stroked by the experimenter's fingers. During week 6, each rat's anxiety level was evaluated in the elevated plus-maze (EPM) test. Learning and memory were evaluated 48 h later, by measuring escape latency in the elevated plus-maze test. Plasma corticosterone and catecholamine levels were measured also. Norepinephrine levels were lower in the handled rats compared with control animals, with no differences in epinephrine and corticosterone. As compared with the control rats, the handled rats showed increases in the percentage of time spent in the open arms of the test apparatus, percentage of entries into open arms, and number of visits to the end of the open arms and decreases in the latency of the first open arm entry. Escape latency was lower in the handled rats compared with control rats in both the first and second trials. The data obtained suggest that handling decreases anxiety levels and improves learning skills and memory in rats. PMID:23312082

Nucleus incertus inactivation impairs spatial learning and memory in rats.

PubMed

Nategh, Mohsen; Nikseresht, Sara; Khodagholi, Fariba; Motamedi, Fereshteh

2015-02-01

Nucleus incertus (NI) is a pontine nucleus which releases mainly GABA and relaxin-3 in rats. Its suggested functions include response to stress, arousal, and modulation of hippocampal theta rhythm. Since the role of NI in learning and memory has not been well characterized, therefore the involvement of this nucleus in spatial learning and memory and the aftermath hippocampal levels of c-fos and pCREB were evaluated. NI was targeted by implanting cannula in male rats. For reference memory, NI was inactivated by lidocaine (0.4 μl, 4%) at three stages of acquisition, consolidation and retrieval in Morris water maze paradigm. For working memory, NI was inactivated in acquisition and retrieval phases. Injection of lidocaine prior to the first training session of reference memory significantly increased the distance moved, suggesting that inactivation of NI delays acquisition in this spatial task. Inactivation also interfered with the retrieval phase of spatial reference memory, as the time in target quadrant for lidocaine group was less, and the escape latency was higher compared to the control group. However, no difference was observed in the consolidation phase. In the working memory task, with inter-trial intervals of 75 min, the escape latency was higher when NI was inactivated in the retrieval phase. In addition, c-fos and pCREB/CREB levels decreased in NI-inhibited rats. This study suggests that nucleus incertus might participate in acquisition of spatial reference, and retrieval of both spatial reference and working memory. Further studies should investigate possible roles of NI in the hippocampal plasticity. Copyright © 2014 Elsevier Inc. All rights reserved.

Vividness of visual imagery and incidental recall of verbal cues, when phenomenological availability reflects long-term memory accessibility.

PubMed

D'Angiulli, Amedeo; Runge, Matthew; Faulkner, Andrew; Zakizadeh, Jila; Chan, Aldrich; Morcos, Selvana

2013-01-01

The relationship between vivid visual mental images and unexpected recall (incidental recall) was replicated, refined, and extended. In Experiment 1, participants were asked to generate mental images from imagery-evoking verbal cues (controlled on several verbal properties) and then, on a trial-by-trial basis, rate the vividness of their images; 30 min later, participants were surprised with a task requiring free recall of the cues. Higher vividness ratings predicted better incidental recall of the cues than individual differences (whose effect was modest). Distributional analysis of image latencies through ex-Gaussian modeling showed an inverse relation between vividness and latency. However, recall was unrelated to image latency. The follow-up Experiment 2 showed that the processes underlying trial-by-trial vividness ratings are unrelated to the Vividness of Visual Imagery Questionnaire (VVIQ), as further supported by a meta-analysis of a randomly selected sample of relevant literature. The present findings suggest that vividness may act as an index of availability of long-term sensory traces, playing a non-epiphenomenal role in facilitating the access of those memories.

Vividness of Visual Imagery and Incidental Recall of Verbal Cues, When Phenomenological Availability Reflects Long-Term Memory Accessibility

PubMed Central

D’Angiulli, Amedeo; Runge, Matthew; Faulkner, Andrew; Zakizadeh, Jila; Chan, Aldrich; Morcos, Selvana

2013-01-01

The relationship between vivid visual mental images and unexpected recall (incidental recall) was replicated, refined, and extended. In Experiment 1, participants were asked to generate mental images from imagery-evoking verbal cues (controlled on several verbal properties) and then, on a trial-by-trial basis, rate the vividness of their images; 30 min later, participants were surprised with a task requiring free recall of the cues. Higher vividness ratings predicted better incidental recall of the cues than individual differences (whose effect was modest). Distributional analysis of image latencies through ex-Gaussian modeling showed an inverse relation between vividness and latency. However, recall was unrelated to image latency. The follow-up Experiment 2 showed that the processes underlying trial-by-trial vividness ratings are unrelated to the Vividness of Visual Imagery Questionnaire (VVIQ), as further supported by a meta-analysis of a randomly selected sample of relevant literature. The present findings suggest that vividness may act as an index of availability of long-term sensory traces, playing a non-epiphenomenal role in facilitating the access of those memories. PMID:23382719

Effect of feeding patterns on performance of a visuospatial memory task in the beagle dog: a novel cognitive-based protocol for assessing satiety.

PubMed

Chan, Joan W C; Araujo, Joseph A; Zicker, Steven C; Pun, Teresa W C; Milgram, Norton W

2005-03-01

The assessment of appetite suppressing effects, or satiating effects, of drugs or other treatments is typically based on the measurement of food consumption and body weight. The present study describes a novel cognitive-based protocol for assessing satiety in the dog based on response latency and performance accuracy on a canine test of spatial working memory, the three-component delayed-non-matching-to-position task (3cDNMP). We hypothesized that satiety, produced by providing food prior to testing, would reduce motivation to respond quickly and accurately on this food-reinforced task. Dogs were first over-trained on a variable-delay version of the 3cDNMP task. They were then pre-fed with either a single or a double portion of food prior to being tested on the same task. Pre-feeding slowed response latency, but had no effect on performance accuracy. A more pronounced increase in response latency was observed in young dogs than in old dogs when offered double portions of food. These results suggest, first, that spatial working memory capability is independent of motivation; second, that satiety is age sensitive; and third, that a cognitive protocol can provide a reliable method for evaluating the satiating effects of various foods and other compounds in the dog.

FPGA cluster for high-performance AO real-time control system

NASA Astrophysics Data System (ADS)

Geng, Deli; Goodsell, Stephen J.; Basden, Alastair G.; Dipper, Nigel A.; Myers, Richard M.; Saunter, Chris D.

2006-06-01

Whilst the high throughput and low latency requirements for the next generation AO real-time control systems have posed a significant challenge to von Neumann architecture processor systems, the Field Programmable Gate Array (FPGA) has emerged as a long term solution with high performance on throughput and excellent predictability on latency. Moreover, FPGA devices have highly capable programmable interfacing, which lead to more highly integrated system. Nevertheless, a single FPGA is still not enough: multiple FPGA devices need to be clustered to perform the required subaperture processing and the reconstruction computation. In an AO real-time control system, the memory bandwidth is often the bottleneck of the system, simply because a vast amount of supporting data, e.g. pixel calibration maps and the reconstruction matrix, need to be accessed within a short period. The cluster, as a general computing architecture, has excellent scalability in processing throughput, memory bandwidth, memory capacity, and communication bandwidth. Problems, such as task distribution, node communication, system verification, are discussed.

Neuroprotective and cognitive enhancing activity of the fermented Bozhougyiqi-Tang

PubMed Central

Weon, Jin Bae; Lee, Bohyoung; Yun, Bo-Ra; Lee, Jiwoo; Ma, Jin Y; Ma, Choong Je

2014-01-01

Background: Alzheimer's disease is a neurodegenerative disease related to memory impairments and neuronal cell death. Bozhougyiqi-Tang (BZYQT), a traditional herbal medicine, has been therapeutically used for the treatment of pulmonary tuberculosis. Objective: The aim of this study is to evaluated the neuroprotective effect of the fermented BZYQT and compared with unfermented BZYQT in HT22 cells by MTT assay and tested the beneficial effect on memory impairments induced by scopolamine (1 mg/kg, i.p.) using the passive avoidance and Morris water maze tests. Results: Compared with unfermented BZYQT, the neuroprotective effect of fermented BZYQT on glutamate induced neurotoxicity in HT22 cells increased at a concentration of 100 μg/mL. Fermented BZYQT increased the step-through latency of the passive avoidance response. Furthermore, in Morris water maze test for evaluation of spatial learning and memory, escape latency time was significantly reduced by fermented BZYQT. Conclusion: These results suggest that the fermentation process of BZYQT led to improve neuroprotective and cognitive enhancing effect. PMID:24991099

Is prospective memory enhanced by cue-action semantic relatedness and enactment at encoding?

PubMed

Pereira, Antonina; Ellis, Judi; Freeman, Jayne

2012-09-01

Benefits and costs on prospective memory performance, of enactment at encoding and a semantic association between a cue-action word pair, were investigated in two experiments. Findings revealed superior performance for both younger and older adults following enactment, in contrast to verbal encoding, and when cue-action semantic relatedness was high. Although younger adults outperformed older adults, age did not moderate benefits of cue-action relatedness or enactment. Findings from a second experiment revealed that the inclusion of an instruction to perform a prospective memory task led to increments in response latency to items from the ongoing activity in which that task was embedded, relative to latencies when the ongoing task only was performed. However, this task interference 'cost' did not differ as a function of either cue-action relatedness or enactment. We argue that the high number of cue-action pairs employed here influenced meta-cognitive consciousness, hence determining attention allocation, in all experimental conditions. Copyright © 2012 Elsevier Inc. All rights reserved.

Methods for compressible fluid simulation on GPUs using high-order finite differences

NASA Astrophysics Data System (ADS)

Pekkilä, Johannes; Väisälä, Miikka S.; Käpylä, Maarit J.; Käpylä, Petri J.; Anjum, Omer

2017-08-01

We focus on implementing and optimizing a sixth-order finite-difference solver for simulating compressible fluids on a GPU using third-order Runge-Kutta integration. Since graphics processing units perform well in data-parallel tasks, this makes them an attractive platform for fluid simulation. However, high-order stencil computation is memory-intensive with respect to both main memory and the caches of the GPU. We present two approaches for simulating compressible fluids using 55-point and 19-point stencils. We seek to reduce the requirements for memory bandwidth and cache size in our methods by using cache blocking and decomposing a latency-bound kernel into several bandwidth-bound kernels. Our fastest implementation is bandwidth-bound and integrates 343 million grid points per second on a Tesla K40t GPU, achieving a 3 . 6 × speedup over a comparable hydrodynamics solver benchmarked on two Intel Xeon E5-2690v3 processors. Our alternative GPU implementation is latency-bound and achieves the rate of 168 million updates per second.

Acute Effects of Ecstasy on Memory Are more Extensive than Chronic Effects.

PubMed

Shariati, Mohamad Bakhtiar Hesam; Sohrabi, Maryam; Shahidi, Siamak; Nikkhah, Ali; Mirzaei, Fatemeh; Medizadeh, Mehdi; Asl, Sara Soleimani

2014-01-01

Exposure to 3, 4- methylenedioxymethamphetamine (MDMA) could lead to serotonergic system toxicity in the brain. This system is responsible for learning and memory functions. Studies show that MDMA causes memory impairment dose-dependently and acutely. The present study was designed to evaluate the chronic and acute effects of MDMD on spatial memory and acquisition of passive avoidance. Adult male Wistar rats (200-250 g) were given single or multiple injections of MDMA (10 mg/kg, IP). Using passive avoidance and Morris Water Maze (MWM) tasks, learning and spatial memory functions were assessed. The data were analyzed by SPSS 16 software and one- way analysis of variance (ANOVA) test. Our results showed that there were significant differences in latency to enter the dark compartment (STL) between sham and MDMA- treated groups. Acute group significantly showed more STL in comparison with chronic group. Furthermore, MDMA groups spent more time in dark compartment (TDS) than the sham group. Administration of single dose of MDMA significantly caused an increase in TDS compared with the chronic group. In the MWM, MDMA treatment significantly increased the traveled distance and escaped latency compared to the sham group. Like to passive avoidance task, percentage of time spent in the target quadrant in MDMA- treated animals impaired in MWM compared with sham group. These data suggest that MDMA treatment impairs learning and memory functions that are more extensive in acute- treated rats.

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

PubMed Central

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

Anti-Alzheimer activity of isolated karanjin from Pongamia pinnata (L.) pierre and embelin from Embelia ribes Burm.f.

PubMed

Saini, Prachi; Lakshmayya, L; Bisht, Vinod Singh

2017-01-01

The aim of this study is to find out the anti-Alzheimer's activity of isolated karanjin and embelin. Karanjin isolated from Pongamia pinnata (L.) pierre and embelin from Embelia ribes Burm.f. and their purity was confirmed by ultraviolet spectrophotometric and Thin layer chromatography based study. Anti-Alzheimer's activity of isolated compounds were evaluated through elevated plus maze and Morris water maze model on Swiss albino mice. Diazepam (1 mg/kg body weight, intraperitoneally) was used for the induction of Alzheimer's like effects (amnesia) on Swiss albino mice and piracetam (200 mg/kg body weight, oral) used as a standard treatment. In EPM, embelin and karanjin decrease the transfer latency time in dose dependent manner and escape latency time in MWM method. A significant ( P < 0.01) reduction in amnesia with an anti-Alzheimer's effect found when results of isolated compounds were compared with standard and vehicle control. Diazepam (1 mg/kg) treated group showed significant increase in escape latency and transfer latency when compared with vehicle control; which indicates impairment in learning and memory. Both isolated compounds and standard significantly reversed the amnesia induced by diazepam and improved learning and memory of mice in dose and time dependent manner. This study supports the ethnobotanical use of these two plants in India for the management of nerve or brain related problems.

Epigenetic dysregulation of epstein-barr virus latency and development of autoimmune disease.

PubMed

Niller, Hans Helmut; Wolf, Hans; Ay, Eva; Minarovits, Janos

2011-01-01

Epstein-Barr virus (EBV) is ahumanherpesvirus thatpersists in the memory B-cells of the majority of the world population in a latent form. Primary EBV infection is asymptomatic or causes a self-limiting disease, infectious mononucleosis. Virus latency is associated with a wide variety of neoplasms whereof some occur in immune suppressed individuals. Virus production does not occur in strict latency. The expression of latent viral oncoproteins and nontranslated RNAs is under epigenetic control via DNA methylation and histone modifications that results either in a complete silencing of the EBV genome in memory B cells, or in a cell-type dependent usage of a couple of latency promoters in tumor cells, germinal center B cells and lymphoblastoid cells (LCL, transformed by EBV in vitro). Both, latent and lytic EBV proteins elicit a strong immune response. In immune suppressed and infectious mononucleosis patients, an increased viral load can be detected in the blood. Enhanced lytic replication may result in new infection- and transformation-events and thus is a risk factor both for malignant transformation and the development of autoimmune diseases. An increased viral load or a changed presentation of a subset of lytic or latent EBV proteins that cross-react with cellular antigens may trigger pathogenic processes through molecular mimicry that result in multiple sclerosis (MS), systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA).

Nimodipine prevents memory impairment caused by nitroglycerin-induced hypotension in adult mice.

PubMed

Bekker, Alex; Haile, Michael; Li, Yong-Sheng; Galoyan, Samuel; Garcia, Edwardo; Quartermain, David; Kamer, Angela; Blanck, Thomas

2009-12-01

Hypotension and a resultant decrease in cerebral blood flow have been implicated in the development of cognitive dysfunction. We tested the hypothesis that nimodipine (NIMO) administered at the onset of nitroglycerin (NTG)-induced hypotension would preserve long-term associative memory. The passive avoidance (PA) paradigm was used to assess memory retention. For PA training, latencies (seconds) were recorded for entry from a suspended platform into a Plexiglas tube where a shock was automatically delivered. Latencies were recorded 48 h later for a testing trial. Ninety-six Swiss-Webster mice (30-35 g, 6-8 wk), were randomized into 6 groups 1) saline (control), 2) NTG immediately after learning, 3) NTG 3 h after learning, 4) NTG and NIMO, 5) vehicle, and 6) NIMO alone. The extent of hypotension and changes in brain tissue oxygenation (PbtO(2)) and in cerebral blood flow were studied in a separate group of animals. All groups exhibited similar training latencies (17.0 +/- 4.6 s). Mice subjected to hypotensive episodes showed a significant decrease in latency time (178 +/- 156 s) compared with those injected with saline, NTG + NIMO, or delayed NTG (580 +/- 81 s, 557 +/- 67 s, and 493 +/- 146 s, respectively). A Kruskal-Wallis 1-way analysis of variance indicated a significant difference among the 4 treatment groups (H = 15.34; P < 0.001). In a separate group of mice not subjected to behavioral studies, the same dose of NTG (n = 3) and NTG + NIMO (n = 3) caused mean arterial blood pressure to decrease from 85.9 +/- 3.8 mm Hg sem to 31.6 +/- 0.8 mm Hg sem and from 86.2 +/- 3.7 mm Hg sem to 32.6 +/- 0.2 mm Hg sem, respectively. Mean arterial blood pressure in mice treated with NIMO alone decreased from 88.1 +/- 3.8 mm Hg to 80.0 +/- 2.9 mm Hg. The intergroup difference was statistically significant (P < 0.05). PbtO(2) decreased from 51.7 +/- 4.5 mm Hg sem to 33.8 +/- 5.2 mm Hg sem in the NTG group and from 38.6 +/- 6.1 mm Hg sem to 25.4 +/- 2.0 mm Hg sem in the NTG + NIMO groups, respectively. There were no significant differences among groups. In a PA retention paradigm, the injection of NTG immediately after learning produced a significant impairment of long-term associative memory in mice, whereas delayed induced hypotension had no effect. NIMO attenuated the disruption in consolidation of long-term memory caused by NTG but did not improve latency in the absence of hypotension. The observed effect of NIMO may have been attributable to the preservation of calcium homeostasis during hypotension, because there were no differences in the PbtO(2) indices among groups.

Passive movement improves the learning and memory function of rats with cerebral infarction by inhibiting neuron cell apoptosis.

PubMed

Li, Man; Peng, Jun; Wang, Meng-Die; Song, Yan-Ling; Mei, Yuan-Wu; Fang, Yuan

2014-02-01

Passive movement has been found to improve evidently ischemic stroke patients' impaired capacity of learning and memory, but the optimal time window of initiating the therapy and the underlying mechanism are not fully understood. In this study, the effect of passive movement at different time windows on learning and memory of rats with cerebral infarction was detected. The results showed that the expression of caspase-3 and escape latency in the passive movement group were all considerably lower than those in the model group (P < 0.05), while the expression of Bcl-2 mRNA was significantly higher than those in the model group (P < 0.05). Moreover, we found that there were most significant changes of escape latency and expressions of Bcl-2 mRNA and caspase-3 when the therapy started at 24 h after focal cerebral infarction. These results suggest that passive movement is able to contribute to the recovery of learning and memory of rats with cerebral infarction, which is partially mediated by inhibiting neuron cell apoptosis, and the optimal therapeutic time is at 24 h after cerebral infarction.

Zinc deficiency with reduced mastication impairs spatial memory in young adult mice.

PubMed

Kida, Kumiko; Tsuji, Tadataka; Tanaka, Susumu; Kogo, Mikihiko

2015-12-01

Sufficient oral microelements such as zinc and fully chewing of foods are required to maintain cognitive function despite aging. No knowledge exists about the combination of factors such as zinc deficiency and reduced mastication on learning and memory. Here we show that tooth extraction only in 8-week-old mice did not change the density of glial fibrillary acidic protein-labeled astrocytes in the hippocampus or spatial memory parameters. However, tooth extraction followed by zinc deprivation strongly impaired spatial memory and led to an increase in astrocytic density in the hippocampal CA1 region. The impaired spatial performance in the zinc-deficient only (ZD) mice also coincided well with the increase in the astrocytic density in the hippocampal CA1 region. After switching both zinc-deficient groups to a normal diet with sufficient zinc, spatial memory recovered, and more time was spent in the quadrant with the goal in the probe test in the mice with tooth extraction followed by zinc deprivation (EZD) compared to the ZD mice. Interestingly, we found no differences in astrocytic density in the CA1 region among all groups at 22 weeks of age. Furthermore, the escape latency in a visible probe test at all times was longer in zinc-deficient groups than the others and demonstrated a negative correlation with body weight. No significant differences in escape latency were observed in the visible probe test among the ZD, EZD, and normal-fed control at 4 weeks (CT4w) groups in which body weight was standardized to that of the EZD group, or in the daily reduction in latency between the normal-fed control and CT4w groups. Our data showed that zinc-deficient feeding during a young age impairs spatial memory performance and leads to an increase in astrocytic density in the hippocampal CA1 region and that zinc-sufficient feeding is followed by recovery of the impaired spatial memory along with changes in astrocytic density. The combination of the two factors, zinc deficiency and reduced mastication, but not body weight, may inhibit recovery of impaired spatial learning. A zinc-sufficient diet is pivotal for maintaining spatial memory. Copyright © 2015 Elsevier Inc. All rights reserved.

Overgeneral autobiographical memory in patients with chronic pain.

PubMed

Liu, Xianhua; Liu, Yanling; Li, Li; Hu, Yiqiu; Wu, Siwei; Yao, Shuqiao

2014-03-01

Overgenerality and delay of the retrieval of autobiographical memory (AM) are well documented in a range of clinical conditions, particularly in patients with emotional disorder. The present study extended the investigation to chronic pain, attempting to identify whether the retrieval of AM in patients with chronic pain tends to be overgeneral or delayed. With an observational cross-sectional design, we evaluated the AM both in patients with chronic pain and healthy controls by Autobiographical Memory Test. Pain conditions were assessed using the pain diagnostic protocol, the short-form McGill Pain Questionnaire (SF-MPQ), and the Pain Self-Efficacy Questionnaire (PSEQ). Emotion was assessed using the Beck Depression Inventory-II (BDI-II) and the Beck Anxiety Inventory. Subjects included 176 outpatients with chronic pain lasting for at least 6 months and 170 healthy controls. 1) Compared with the healthy group, the chronic pain group had more overgeneral memories (OGMs) (F = 29.061, P < 0.01) and longer latency (F = 13.602, P < 0.01). 2) In the chronic pain group, the stepwise multiple regression models for variables predicting OGM were significant (P < 0.01). Specifically, the variance in OGM scores could be predicted by the BDI score (9.7%), pain chronicity (4.3%), PSEQ score (7.1%), and Affective Index (of SF-MPQ) score (2.7%). 3) In the chronic pain group, the stepwise multiple regression models for variables predicting latency were significant (P < 0.05). Specifically, the variance in latency could be predicted by age (3.1%), pain chronicity (2.7%), pain duration (4.3%), and PSEQ score (2.0%). The retrieval of AM in patients with chronic pain tends to be overgeneral and delayed, and the retrieval style of AM may be contributed to negative emotions and chronic pain conditions. Wiley Periodicals, Inc.

Exercise reduces diet-induced cognitive decline and increases hippocampal brain-derived neurotrophic factor in CA3 neurons

PubMed Central

Noble, Emily E.; Mavanji, Vijayakumar; Little, Morgan R.; Billington, Charles J.; Kotz, Catherine M.; Wang, ChuanFeng

2014-01-01

Background Previous studies have shown that a western diet impairs, whereas physical exercise enhances hippocampus-dependent learning and memory. Both diet and exercise influence expression of hippocampal brain-derived neurotrophic factor (BDNF), which is associated with improved cognition. We hypothesized that exercise reverses diet-induced cognitive decline while increasing hippocampal BDNF. Methods To test the effects of exercise on hippocampal-dependent memory, we compared cognitive scores of Sprague-Dawley rats exercised by voluntary running wheel (RW) access or forced treadmill (TM) to sedentary (Sed) animals. Memory was tested by two-way active avoidance test (TWAA), in which animals are exposed to a brief shock in a specific chamber area. When an animal avoids, escapes or has reduced latency to do either, this is considered a measure of memory. In a second experiment, rats were fed either a high-fat diet or control diet for 16 weeks, then randomly assigned to running wheel access or sedentary condition, and TWAA memory was tested once a week for seven weeks of exercise intervention. Results Both groups of exercised animals had improved memory as indicated by reduced latency to avoid and escape shock, and increased avoid and escape episodes (p<0.05). Exposure to a high-fat diet resulted in poor performance during both the acquisition and retrieval phases of the memory test as compared to controls. Exercise reversed high-fat diet-induced memory impairment, and increased brain-derived neurotrophic factor (BDNF) in neurons of the hippocampal CA3 region. Conclusions These data suggest that exercise improves memory retrieval, particularly with respect to avoiding aversive stimuli, and may be beneficial in protecting against diet induced cognitive decline, likely via elevated BDNF in neurons of the CA3 region. PMID:24755094

Exercise reduces diet-induced cognitive decline and increases hippocampal brain-derived neurotrophic factor in CA3 neurons.

PubMed

Noble, Emily E; Mavanji, Vijayakumar; Little, Morgan R; Billington, Charles J; Kotz, Catherine M; Wang, ChuanFeng

2014-10-01

Previous studies have shown that a western diet impairs, whereas physical exercise enhances hippocampus-dependent learning and memory. Both diet and exercise influence expression of hippocampal brain-derived neurotrophic factor (BDNF), which is associated with improved cognition. We hypothesized that exercise reverses diet-induced cognitive decline while increasing hippocampal BDNF. To test the effects of exercise on hippocampal-dependent memory, we compared cognitive scores of Sprague-Dawley rats exercised by voluntary running wheel (RW) access or forced treadmill (TM) to sedentary (Sed) animals. Memory was tested by two-way active avoidance test (TWAA), in which animals are exposed to a brief shock in a specific chamber area. When an animal avoids, escapes or has reduced latency to do either, this is considered a measure of memory. In a second experiment, rats were fed either a high-fat diet or control diet for 16 weeks, then randomly assigned to running wheel access or sedentary condition, and TWAA memory was tested once a week for 7 weeks of exercise intervention. Both groups of exercised animals had improved memory as indicated by reduced latency to avoid and escape shock, and increased avoid and escape episodes (p<0.05). Exposure to a high-fat diet resulted in poor performance during both the acquisition and retrieval phases of the memory test as compared to controls. Exercise reversed high-fat diet-induced memory impairment, and increased brain-derived neurotrophic factor (BDNF) in neurons of the hippocampal CA3 region. These data suggest that exercise improves memory retrieval, particularly with respect to avoiding aversive stimuli, and may be beneficial in protecting against diet induced cognitive decline, likely via elevated BDNF in neurons of the CA3 region. Published by Elsevier Inc.

Spatial and Working Memory Is Linked to Spine Density and Mushroom Spines

PubMed Central

Aher, Yogesh D.; Sase, Ajinkya; Gröger, Marion; Mokhtar, Maher; Höger, Harald; Lubec, Gert

2015-01-01

Background Changes in synaptic structure and efficacy including dendritic spine number and morphology have been shown to underlie neuronal activity and size. Moreover, the shapes of individual dendritic spines were proposed to correlate with their capacity for structural change. Spine numbers and morphology were reported to parallel memory formation in the rat using a water maze but, so far, there is no information on spine counts or shape in the radial arm maze (RAM), a frequently used paradigm for the evaluation of complex memory formation in the rodent. Methods 24 male Sprague-Dawley rats were divided into three groups, 8 were trained, 8 remained untrained in the RAM and 8 rats served as cage controls. Dendritic spine numbers and individual spine forms were counted in CA1, CA3 areas and dentate gyrus of hippocampus using a DIL dye method with subsequent quantification by the Neuronstudio software and the image J program. Results Working memory errors (WME) and latency in the RAM were decreased along the training period indicating that animals performed the task. Total spine density was significantly increased following training in the RAM as compared to untrained rats and cage controls. The number of mushroom spines was significantly increased in the trained as compared to untrained and cage controls. Negative significant correlations between spine density and WME were observed in CA1 basal dendrites and in CA3 apical and basal dendrites. In addition, there was a significant negative correlation between spine density and latency in CA3 basal dendrites. Conclusion The study shows that spine numbers are significantly increased in the trained group, an observation that may suggest the use of this method representing a morphological parameter for memory formation studies in the RAM. Herein, correlations between WME and latency in the RAM and spine density revealed a link between spine numbers and performance in the RAM. PMID:26469788

State orientation and memory load impair prospective memory performance in older compared to younger persons.

PubMed

Kaschel, Reiner; Kazén, Miguel; Kuhl, Julius

2017-07-01

A modified event-based paradigm of prospective memory was applied to investigate intention initiation in older and younger participants under high versus low memory load (subsequent episodic word recall vs. recognition). State versus action orientation, a personality dimension related to intention enactment, was also measured. State-oriented persons show a superiority effect for the storage of intentions in an explicit format but have a paradoxical deficit in their actual enactment. We predicted an interaction between aging, personality, and memory load, with longer intention-initiation latencies and higher omission rates for older state-oriented participants under high memory load. Results were consistent with predictions and are interpreted according to current personality and prospective memory models of aging.

Prolongation of latencies for passive avoidance responses in rats treated with aniracetam or piracetam.

PubMed

Yamada, K; Inoue, T; Tanaka, M; Furukawa, T

1985-04-01

Effects of aniracetam (1-anysoyl-2-pyrrolodone) and piracetam (1-acetamido-2-pyrrolidone) on passive avoidance behavior were studied in 2 and 18 months old rats using a step-down passive avoidance task. Repeated administration of aniracetam (30 and 50 mg/kg, IP X 5 days) or piracetam (100 mg/kg, IP X 5 days) significantly prolonged step-down latencies for a passive avoidance task in 2 months old rats. Administration of aniracetam (50 mg/kg, IP) or piracetam (100 mg/kg, IP), however, did not affect locomotor activity. This prolongation of latencies was also seen with oral administration of aniracetam (50 mg/kg X 5 days). Similar prolongation of latencies also occurred in 18 months old rat treated with aniracetam (50 mg/kg, IP X 5 days). The results imply that aniracetam may improve learning and/or memory in 2 and 18 months old rats.

On the Floating Point Performance of the i860 Microprocessor

NASA Technical Reports Server (NTRS)

Lee, King; Kutler, Paul (Technical Monitor)

1997-01-01

The i860 microprocessor is a pipelined processor that can deliver two double precision floating point results every clock. It is being used in the Touchstone project to develop a teraflop computer by the year 2000. With such high computational capabilities it was expected that memory bandwidth would limit performance on many kernels. Measured performance of three kernels showed performance is less than what memory bandwidth limitations would predict. This paper develops a model that explains the discrepancy in terms of memory latencies and points to some problems involved in moving data from memory to the arithmetic pipelines.

Relationship between early and late stages of information processing: an event-related potential study

PubMed Central

Portella, Claudio; Machado, Sergio; Arias-Carrión, Oscar; Sack, Alexander T.; Silva, Julio Guilherme; Orsini, Marco; Leite, Marco Antonio Araujo; Silva, Adriana Cardoso; Nardi, Antonio E.; Cagy, Mauricio; Piedade, Roberto; Ribeiro, Pedro

2012-01-01

The brain is capable of elaborating and executing different stages of information processing. However, exactly how these stages are processed in the brain remains largely unknown. This study aimed to analyze the possible correlation between early and late stages of information processing by assessing the latency to, and amplitude of, early and late event-related potential (ERP) components, including P200, N200, premotor potential (PMP) and P300, in healthy participants in the context of a visual oddball paradigm. We found a moderate positive correlation among the latency of P200 (electrode O2), N200 (electrode O2), PMP (electrode C3), P300 (electrode PZ) and the reaction time (RT). In addition, moderate negative correlation between the amplitude of P200 and the latencies of N200 (electrode O2), PMP (electrode C3), P300 (electrode PZ) was found. Therefore, we propose that if the secondary processing of visual input (P200 latency) occurs faster, the following will also happen sooner: discrimination and classification process of this input (N200 latency), motor response processing (PMP latency), reorganization of attention and working memory update (P300 latency), and RT. N200, PMP, and P300 latencies are also anticipated when higher activation level of occipital areas involved in the secondary processing of visual input rise (P200 amplitude). PMID:23355929

Performance and evaluation of real-time multicomputer control systems

NASA Technical Reports Server (NTRS)

Shin, K. G.

1985-01-01

Three experiments on fault tolerant multiprocessors (FTMP) were begun. They are: (1) measurement of fault latency in FTMP; (2) validation and analysis of FTMP synchronization protocols; and investigation of error propagation in FTMP.

Improved cache performance in Monte Carlo transport calculations using energy banding

NASA Astrophysics Data System (ADS)

Siegel, A.; Smith, K.; Felker, K.; Romano, P.; Forget, B.; Beckman, P.

2014-04-01

We present an energy banding algorithm for Monte Carlo (MC) neutral particle transport simulations which depend on large cross section lookup tables. In MC codes, read-only cross section data tables are accessed frequently, exhibit poor locality, and are typically too much large to fit in fast memory. Thus, performance is often limited by long latencies to RAM, or by off-node communication latencies when the data footprint is very large and must be decomposed on a distributed memory machine. The proposed energy banding algorithm allows maximal temporal reuse of data in band sizes that can flexibly accommodate different architectural features. The energy banding algorithm is general and has a number of benefits compared to the traditional approach. In the present analysis we explore its potential to achieve improvements in time-to-solution on modern cache-based architectures.

Individual differences in working memory capacity and search efficiency.

PubMed

Miller, Ashley L; Unsworth, Nash

2018-05-29

In two experiments, we examined how various learning conditions impact the relation between working memory capacity (WMC) and memory search abilities. Experiment 1 employed a delayed free recall task with semantically related words to induce the buildup of proactive interference (PI) and revealed that the buildup of PI differentially impacted recall accuracy and recall latency for low-WMC and high-WMC individuals. Namely, the buildup of PI impaired recall accuracy and slowed recall latency for low-WMC individuals to a greater extent than what was observed for high-WMC individuals. To provide a circumstance in which previously learned information remains relevant over the course of learning, Experiment 2 required participants to complete a multitrial delayed free recall task with unrelated words. Results revealed that with increased practice with the same word list, WMC-related differences were eventually eliminated in interresponse times (IRTs) and recall accuracy, but not recall latency. Thus, despite still accumulating larger search sets, low-WMC individuals searched LTM as efficiently as high-WMC individuals. Collectively, these results are consistent with the notion that under normal free recall conditions, low-WMC individuals search LTM less efficiently than do high-WMC individuals because of their reliance on noisy temporal-contextual cues at retrieval. However, it appears that under conditions in which previously learned items remain relevant at recall, this tendency to rely on vague self-generated retrieval cues can actually facilitate the ability to accurately and quickly recall information.

Original nootropic drug noopept prevents memory deficit in rats with muscarinic and nicotinic receptor blockade.

PubMed

Radionova, K S; Belnik, A P; Ostrovskaya, R U

2008-07-01

Antiamnesic activity of Noopept was studied on the original three-way model of conditioned passive avoidance response, which allows studying spatial component of memory. Cholinoceptor antagonists of both types (scopolamine and mecamylamine) decreased entry latency and reduced the probability for selection of the safe compartment. Noopept abolished the antiamnesic effect of cholinoceptor antagonists and improved spatial preference.

Soft-error tolerance and energy consumption evaluation of embedded computer with magnetic random access memory in practical systems using computer simulations

NASA Astrophysics Data System (ADS)

Nebashi, Ryusuke; Sakimura, Noboru; Sugibayashi, Tadahiko

2017-08-01

We evaluated the soft-error tolerance and energy consumption of an embedded computer with magnetic random access memory (MRAM) using two computer simulators. One is a central processing unit (CPU) simulator of a typical embedded computer system. We simulated the radiation-induced single-event-upset (SEU) probability in a spin-transfer-torque MRAM cell and also the failure rate of a typical embedded computer due to its main memory SEU error. The other is a delay tolerant network (DTN) system simulator. It simulates the power dissipation of wireless sensor network nodes of the system using a revised CPU simulator and a network simulator. We demonstrated that the SEU effect on the embedded computer with 1 Gbit MRAM-based working memory is less than 1 failure in time (FIT). We also demonstrated that the energy consumption of the DTN sensor node with MRAM-based working memory can be reduced to 1/11. These results indicate that MRAM-based working memory enhances the disaster tolerance of embedded computers.

Acute Effects of Ecstasy on Memory Are more Extensive than Chronic Effects

PubMed Central

Shariati, Mohamad Bakhtiar Hesam; Sohrabi, Maryam; Shahidi, Siamak; Nikkhah, Ali; Mirzaei, Fatemeh; Medizadeh, Mehdi; Asl, Sara Soleimani

2014-01-01

Introduction Exposure to 3, 4- methylenedioxymethamphetamine (MDMA) could lead to serotonergic system toxicity in the brain. This system is responsible for learning and memory functions. Studies show that MDMA causes memory impairment dose-dependently and acutely. The present study was designed to evaluate the chronic and acute effects of MDMD on spatial memory and acquisition of passive avoidance. Methods Adult male Wistar rats (200-250 g) were given single or multiple injections of MDMA (10 mg/kg, IP). Using passive avoidance and Morris Water Maze (MWM) tasks, learning and spatial memory functions were assessed. The data were analyzed by SPSS 16 software and one- way analysis of variance (ANOVA) test. Results Our results showed that there were significant differences in latency to enter the dark compartment (STL) between sham and MDMA- treated groups. Acute group significantly showed more STL in comparison with chronic group. Furthermore, MDMA groups spent more time in dark compartment (TDS) than the sham group. Administration of single dose of MDMA significantly caused an increase in TDS compared with the chronic group. In the MWM, MDMA treatment significantly increased the traveled distance and escaped latency compared to the sham group. Like to passive avoidance task, percentage of time spent in the target quadrant in MDMA- treated animals impaired in MWM compared with sham group. Discussion These data suggest that MDMA treatment impairs learning and memory functions that are more extensive in acute- treated rats. PMID:25337384

Intracerebroventricular administration of taurine impairs learning and memory in rats.

PubMed

Ito, Koichi; Arko, Matevž; Kawaguchi, Tomohiro; Kikusui, Takefumi; Kuwahara, Masayoshi; Tsubone, Hirokazu

2012-03-01

Taurine is a semi-essential amino acid widely distributed in the body and we take in it from a wide range of nutritive-tonic drinks to improve health. To date, we have elucidated that oral supplementation of taurine does not affect learning and memory in the rat. However, there are few studies concerning the direct effects of taurine in the brain at the behavior level. In this study, we intracerebroventricularly administered taurine to rats and aimed to elucidate the acute effects on learning and memory using the Morris water maze method. Escape latency, swim distance, and distance to zone, which is the integral of the distance between the rats and the platform for every 0.16 seconds, were adopted as parameters of the ability of learning and memory. We also tried to evaluate the effect of intraperitoneal taurine administration. Escape latency, swim distance, and distance to zone were significantly longer in the intracerebroventricularly taurine-administered rats than in the saline-administered rats. Mean swimming velocity was comparable between these two groups, although the physical performance was improved by taurine administration. Probe trials showed that the manner of the rats in finding the platform was comparable. In contrast, no significant differences were found between the intraperitoneally taurine-administered rats and the saline-administered rats. These results indicate that taurine administered directly into the brain ventricle suppresses and delays the ability of learning and memory in rats. In contrast, it is implied that taurine administered peripherally was not involved in learning and memory.

Current-driven domain wall motion based memory devices: Application to a ratchet ferromagnetic strip

NASA Astrophysics Data System (ADS)

Sánchez-Tejerina, Luis; Martínez, Eduardo; Raposo, Víctor; Alejos, Óscar

2018-04-01

Ratchet memories, where perpendicular magnetocristalline anisotropy is tailored so as to precisely control the magnetic transitions, has been recently proven to be a feasible device to store and manipulate data bits. For such devices, it has been shown that the current-driven regime of domain walls can improve their performances with respect to the field-driven one. However, the relaxing time required by the traveling domain walls constitutes a certain drawback if the former regime is considered, since it results in longer device latencies. In order to speed up the bit shifting procedure, it is demonstrated here that the application of a current of inverse polarity during the DW relaxing time may reduce such latencies. The reverse current must be sufficiently high as to drive the DW to the equilibrium position faster than the anisotropy slope itself, but with an amplitude sufficiently low as to avoid DW backward shifting. Alternatively, it is possible to use such a reverse current to increase the proper range of operation for a given relaxing time, i.e., the pair of values of the current amplitude and pulse time that ensures single DW jumps for a certain latency time.

Auditory Brainstem and Middle Latency Responses Measured Pre- and Posttreatment for Hyperacusic Hearing-Impaired Persons Successfully Treated to Improve Sound Tolerance and to Expand the Dynamic Range for Loudness: Case Evidence.

PubMed

Formby, Craig; Korczak, Peggy; Sherlock, LaGuinn P; Hawley, Monica L; Gold, Susan

2017-02-01

In this report of three cases, we consider electrophysiologic measures from three hyperacusic hearing-impaired individuals who, prior to treatment to expand their dynamic ranges for loudness, were problematic hearing aid candidates because of their diminished sound tolerance and reduced dynamic ranges. Two of these individuals were treated with structured counseling combined with low-level broadband sound therapy from bilateral sound generators and the third case received structured counseling in combination with a short-acting placebo sound therapy. Each individual was highly responsive to his or her assigned treatment as revealed by expansion of the dynamic range by at least 20 dB at one or more frequencies posttreatment. Of specific interest in this report are their latency and amplitude measures taken from tone burst-evoked auditory brainstem response (ABR) and cortically derived middle latency response (MLR) recordings, measured as a function of increasing loudness at 500 and 2,000 Hz pre- and posttreatment. The resulting ABR and MLR latency and amplitude measures for each case are considered here in terms of pre- and posttreatment predictions. The respective pre- and posttreatment predictions anticipated larger pretreatment response amplitudes and shorter pretreatment response latencies relative to typical normal control values and smaller normative-like posttreatment response amplitudes and longer posttreatment response latencies relative to the corresponding pretreatment values for each individual. From these results and predictions, we conjecture about the neural origins of the hyperacusis conditions (i.e., brainstem versus cortical) and the neuronal sites responsive to treatment. The only consistent finding in support of the pre- and posttreatment predictions and, thus, the strongest index of hyperacusis and positive treatment-related effects was measured for MLR latency responses for wave Pa at 2,000 Hz. Other response indices, including ABR wave V latency and wave V-V' amplitude and MLR wave Na-Pa amplitude for 500 and 2,000 Hz, appear either ambiguous across and/or within these individuals. Notwithstanding significant challenges for interpreting these findings, including associated confounding effects of their sensorineural hearing losses and differences in the presentation levels of the toneburst stimuli used to collect these measures for each individual, our limited analyses of three cases suggest measures of MLR wave Pa latency at 2,000 Hz (reflecting cortical contributions) may be a promising objective indicator of hyperacusis and dynamic range expansion treatment effects.

Transcriptional Reprogramming during Effector-to-Memory Transition Renders CD4+ T Cells Permissive for Latent HIV-1 Infection.

PubMed

Shan, Liang; Deng, Kai; Gao, Hongbo; Xing, Sifei; Capoferri, Adam A; Durand, Christine M; Rabi, S Alireza; Laird, Gregory M; Kim, Michelle; Hosmane, Nina N; Yang, Hung-Chih; Zhang, Hao; Margolick, Joseph B; Li, Linghua; Cai, Weiping; Ke, Ruian; Flavell, Richard A; Siliciano, Janet D; Siliciano, Robert F

2017-10-17

The latent reservoir for HIV-1 in resting memory CD4 + T cells is the major barrier to curing HIV-1 infection. Studies of HIV-1 latency have focused on regulation of viral gene expression in cells in which latent infection is established. However, it remains unclear how infection initially becomes latent. Here we described a unique set of properties of CD4 + T cells undergoing effector-to-memory transition including temporary upregulation of CCR5 expression and rapid downregulation of cellular gene transcription. These cells allowed completion of steps in the HIV-1 life cycle through integration but suppressed HIV-1 gene transcription, thus allowing the establishment of latency. CD4 + T cells in this stage were substantially more permissive for HIV-1 latent infection than other CD4 + T cells. Establishment of latent HIV-1 infection in CD4 + T could be inhibited by viral-specific CD8 + T cells, a result with implications for elimination of latent HIV-1 infection by T cell-based vaccines. Copyright © 2017. Published by Elsevier Inc.

Multi-Level Bitmap Indexes for Flash Memory Storage

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

Wu, Kesheng; Madduri, Kamesh; Canon, Shane

2010-07-23

Due to their low access latency, high read speed, and power-efficient operation, flash memory storage devices are rapidly emerging as an attractive alternative to traditional magnetic storage devices. However, tests show that the most efficient indexing methods are not able to take advantage of the flash memory storage devices. In this paper, we present a set of multi-level bitmap indexes that can effectively take advantage of flash storage devices. These indexing methods use coarsely binned indexes to answer queries approximately, and then use finely binned indexes to refine the answers. Our new methods read significantly lower volumes of data atmore » the expense of an increased disk access count, thus taking full advantage of the improved read speed and low access latency of flash devices. To demonstrate the advantage of these new indexes, we measure their performance on a number of storage systems using a standard data warehousing benchmark called the Set Query Benchmark. We observe that multi-level strategies on flash drives are up to 3 times faster than traditional indexing strategies on magnetic disk drives.« less

Feeding Vitamin C during Neonatal and Juvenile Growth Improves Learning and Memory of Rats.

PubMed

Hosseini, Mahmoud; Beheshti, Farimah; Sohrabi, Farzaneh; Vafaee, Farzaneh; Shafei, Mohammad Naser; Reza Sadeghnia, Hamid

2018-09-03

We investigated the effects of feeding vitamin C (Vit C) during neonatal and juvenile growth on learning and memory of rats. Rats after delivery were randomly divided into four groups and treated. Group 1, control group, received normal drinking water. Groups 2-4 received Vit C 10, 100, and 500 mg/kg, respectively, from the first day. After 8 weeks, 10 male offspring of each group were randomly selected and tested in the Morris water maze (MWM) and passive avoidance (PA) tests. Finally, the brains were removed for biochemical measurement. In MWM, 10-500 mg/kg Vit C reduced the latency and traveled distance and increased time spent in the target quadrant. In PA, 10 and 100 mg/kg of Vit C increased the latency; 10-500 mg/kg of Vit C decreased the malondialdehyde (MDA) in the brain tissues and increased thiol and catalase (CAT) activity compared to the control group. We showed that feeding rats Vit C during neonatal and juvenile growth has positive effects on learning and memory.

Z-Guggulsterone Improves the Scopolamine-Induced Memory Impairments Through Enhancement of the BDNF Signal in C57BL/6J Mice.

PubMed

Chen, Zhuo; Huang, Chao; Ding, Wenbin

2016-12-01

Memory impairment is a common symptom in patients with neurodegenerative disorders, and its suppression could be beneficial to improve the quality of life of those patients. Z-guggulsterone, a compound extracted from the resin of plant Commiphora whighitii, exhibits numerous pharmacological effects in clinical practice, such as treatment of inflammation, arthritis, obesity and lipid metabolism disorders. However, the role and possible mechanism of Z-guggulsterone on brain-associated memory impairments are largely unknown. This issue was addressed in the present study in a memory impairment model induced by scopolamine, a muscarinic acetylcholine receptor antagonist, using the passive avoidance, Y-maze and Morris water maze tests. Results showed that scopolamine significantly decreased the step-through latency and spontaneous alternation of C57BL/6J mice in passive avoidance and Y-maze test, whereas increased the mean escape latency and decreased the swimming time in target quadrant in Morris water maze test. Pretreatment of mice with Z-guggulsterone at doses of 30 and 60 mg/kg effectively reversed the scopolamine-induced memory impairments. Mechanistic studies revealed that Z-guggulsterone pretreatment reversed the scopolamine-induced increase in acetylcholinesterase (AchE) activity, as well as decreases in brain-derived neurotrophic factor (BDNF) protein expression and cAMP response element-binding protein (CREB), extracellular regulated kinase 1/2 (ERK1/2) and protein kinase B (Akt) phosphorylation levels in the hippocampus and cortex. Inhibition of the BDNF signal, however, blocked the memory-enhancing effect of Z-guggulsterone. Therefore, these findings demonstrate that Z-guggulsterone attenuates the scopolamine-induced memory impairments mainly through activation of the CREB-BDNF signaling pathway, thereby exhibiting memory-improving effects.

Acute restriction impairs memory in the elevated T-maze (ETM) and modifies serotonergic activity in the dorsolateral striatum.

PubMed

Cruz-Morales, Sara Eugenia; García-Saldívar, Norma Laura; González-López, María Reyes; Castillo-Roberto, Georgina; Monroy, Juana; Domínguez, Roberto

2008-12-16

Serotonin (5-HT) is involved in behaviors such as sleep, eating, memory, in mental disorders like anxiety and depression and plays an important role in the modulation of stress. On the other hand, exposure to stress influence learning as well as declarative and non-declarative memory. These effects are dependent on the type of stressor, their magnitude, and the type of memory. The striatum has been associated with non-declarative procedural memory, while the information about stress effects on procedural memory and their relation with striatal serotonin is scarce. The objective of this study was to evaluate the effects of stress on the modifications of the striatal serotonergic system. In Experiment 1, the effects of either 60 min of restraint (R) or exposure to the elevated T-maze (ETM) was assessed. Exposure to ETM decreased 5-HT concentration and to R increased 5-HT activity ([metabolite]/[neurotransmitter]). In Experiment 2, we evaluated the effects of restraint on ETM trained immediately, 24 or 48 h after restraint. No effects were detected in acquisition or escape latencies, while retention latencies were lower in all groups compared with the non-restrained group, although significant effects were detected immediately and 24h after restraint. The memory impairment seems to be associated with changes in striatal serotonergic system, given that 5-HT concentration increased, while serotonergic activity decreased. The differences in the activity of 5-HT detected in each experiment could be explained by the effects of different stressors on the serotonergic neurons ability to synthesize the neurotransmitter. Thus, we suggest that exposure to stress impairs procedural memory and that striatal serotonin modulates this effect.

Anti-Alzheimer activity of isolated karanjin from Pongamia pinnata (L.) pierre and embelin from Embelia ribes Burm.f.

PubMed Central

Saini, Prachi; Lakshmayya, L.; Bisht, Vinod Singh

2017-01-01

Aim: The aim of this study is to find out the anti-Alzheimer’s activity of isolated karanjin and embelin. Materials and Methods: Karanjin isolated from Pongamia pinnata (L.) pierre and embelin from Embelia ribes Burm.f. and their purity was confirmed by ultraviolet spectrophotometric and Thin layer chromatography based study. Anti-Alzheimer’s activity of isolated compounds were evaluated through elevated plus maze and Morris water maze model on Swiss albino mice. Diazepam (1 mg/kg body weight, intraperitoneally) was used for the induction of Alzheimer’s like effects (amnesia) on Swiss albino mice and piracetam (200 mg/kg body weight, oral) used as a standard treatment. Results: In EPM, embelin and karanjin decrease the transfer latency time in dose dependent manner and escape latency time in MWM method. A significant (P < 0.01) reduction in amnesia with an anti-Alzheimer’s effect found when results of isolated compounds were compared with standard and vehicle control. Diazepam (1 mg/kg) treated group showed significant increase in escape latency and transfer latency when compared with vehicle control; which indicates impairment in learning and memory. Conclusion: Both isolated compounds and standard significantly reversed the amnesia induced by diazepam and improved learning and memory of mice in dose and time dependent manner. This study supports the ethnobotanical use of these two plants in India for the management of nerve or brain related problems. PMID:29861598

A primary cell model of HIV-1 latency that uses activation through the T cell receptor and return to quiescence to establish latent infection

PubMed Central

Kim, Michelle; Hosmane, Nina N.; Bullen, C. Korin; Capoferri, Adam; Yang, Hung-Chih; Siliciano, Janet D.; Siliciano, Robert F.

2015-01-01

A mechanistic understanding of HIV-1 latency depends upon a model system that recapitulates the in vivo condition of latently infected, resting CD4+ T lymphocytes. Latency appears to be established after activated CD4+ T cells, the principal targets of HIV-1 infection, become productively infected and survive long enough to return to a resting memory state in which viral expression is inhibited by changes in the cellular environment. This protocol describes an ex vivo primary cell system that is generated under conditions that reflect the in vivo establishment of latency. Creation of these latency model cells takes 12 weeks and, once established, the cells can be maintained and used for several months. The resulting cell population contains both uninfected and latently infected cells. This primary cell model can be used to perform drug screens, study CTL responses to HIV-1, compare viral alleles, or to expand the ex vivo lifespan of cells from HIV-1 infected individuals for extended study. PMID:25375990

The origin of children's implanted false memories: memory traces or compliance?

PubMed

Otgaar, Henry; Verschuere, Bruno; Meijer, Ewout H; van Oorsouw, Kim

2012-03-01

A longstanding question in false memory research is whether children's implanted false memories represent actual memory traces or merely result from compliance. The current study examined this question using a response latency based deception task. Forty-five 8-year-old children received narratives about a true (first day at school) and false event (hot air balloon ride). Across two interviews, 58/32% of the participants developed a partial/full false memory. Interestingly, these children also showed higher false recall on an unrelated DRM paradigm compared to children without a false memory. The crucial finding, however, was that the results of the deception task revealed that children with partial and full false memories were faster to confirm than to deny statements relating to the false event. This indicates that children's implanted false memories reflect actual memory traces, and are unlikely to be explained by mere compliance. Copyright © 2012 Elsevier B.V. All rights reserved.

Federal Plan for High-End Computing. Report of the High-End Computing Revitalization Task Force (HECRTF)

DTIC Science & Technology

2004-07-01

steadily for the past fifteen years, while memory latency and bandwidth have improved much more slowly. For example, Intel processor clock rates38 have... processor and memory performance) all greatly restrict the ability to achieve high levels of performance for science, engineering, and national...sub-nuclear distances. Guide experiments to identify transition from quantum chromodynamics to quark -gluon plasma. Accelerator Physics Accurate

Incidental threat during visuospatial working memory in adolescent anxiety: an emotional memory-guided saccade task.

PubMed

Mueller, Sven C; Shechner, Tomer; Rosen, Dana; Nelson, Eric E; Pine, Daniel S; Ernst, Monique

2015-04-01

Pediatric anxiety disorders are among the most common psychiatric mental illnesses in children and adolescents, and are associated with abnormal cognitive control in emotional, particularly threat, contexts. In a series of studies using eye movement saccade tasks, we reported anxiety-related alterations in the interplay of inhibitory control with incentives, or with emotional distractors. The present study extends these findings to working memory (WM), and queries the interaction of spatial WM with emotional stimuli in pediatric clinical anxiety. Participants were 33 children/adolescents diagnosed with an anxiety disorder, and 22 age-matched healthy comparison youths. Participants completed a novel eye movement task, an affective variant of the memory-guided saccade task. This task assessed the influence of incidental threat on spatial WM processes during high and low cognitive load. Healthy but not anxious children/adolescents showed slowed saccade latencies during incidental threat in low-load but not high-load WM conditions. No other group effects emerged on saccade latency or accuracy. The current data suggest a differential pattern of how emotion interacts with cognitive control in healthy youth relative to anxious youth. These findings extend data from inhibitory processes, reported previously, to spatial WM in pediatric anxiety. © 2015 Wiley Periodicals, Inc.

Memory Network For Distributed Data Processors

NASA Technical Reports Server (NTRS)

Bolen, David; Jensen, Dean; Millard, ED; Robinson, Dave; Scanlon, George

1992-01-01

Universal Memory Network (UMN) is modular, digital data-communication system enabling computers with differing bus architectures to share 32-bit-wide data between locations up to 3 km apart with less than one millisecond of latency. Makes it possible to design sophisticated real-time and near-real-time data-processing systems without data-transfer "bottlenecks". This enterprise network permits transmission of volume of data equivalent to an encyclopedia each second. Facilities benefiting from Universal Memory Network include telemetry stations, simulation facilities, power-plants, and large laboratories or any facility sharing very large volumes of data. Main hub of UMN is reflection center including smaller hubs called Shared Memory Interfaces.

Long-latency auditory evoked potentials with verbal and nonverbal stimuli.

PubMed

Oppitz, Sheila Jacques; Didoné, Dayane Domeneghini; Silva, Débora Durigon da; Gois, Marjana; Folgearini, Jordana; Ferreira, Geise Corrêa; Garcia, Michele Vargas

2015-01-01

Long-latency auditory evoked potentials represent the cortical activity related to attention, memory, and auditory discrimination skills. Acoustic signal processing occurs differently between verbal and nonverbal stimuli, influencing the latency and amplitude patterns. To describe the latencies of the cortical potentials P1, N1, P2, N2, and P3, as well as P3 amplitude, with different speech stimuli and tone bursts, and to classify them in the presence and absence of these data. A total of 30 subjects with normal hearing were assessed, aged 18-32 years old, matched by gender. Nonverbal stimuli were used (tone burst; 1000Hz - frequent and 4000Hz - rare); and verbal (/ba/ - frequent; /ga/, /da/, and /di/ - rare). Considering the component N2 for tone burst, the lowest latency found was 217.45ms for the BA/DI stimulus; the highest latency found was 256.5ms. For the P3 component, the shortest latency with tone burst stimuli was 298.7 with BA/GA stimuli, the highest, was 340ms. For the P3 amplitude, there was no statistically significant difference among the different stimuli. For latencies of components P1, N1, P2, N2, P3, there were no statistical differences among them, regardless of the stimuli used. There was a difference in the latency of potentials N2 and P3 among the stimuli employed but no difference was observed for the P3 amplitude. Copyright © 2015 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

The Association between Obesity and Cognitive Function in Otherwise Healthy Premenopausal Arab Women.

PubMed

Farooq, Abdulaziz; Gibson, Ann-Marie; J Reilly, John; Gaoua, Nadia

2018-01-01

To examine the association between obesity and cognitive function in healthy premenopausal women. From a cohort of 220 women, 98 were randomly selected that provided complete data. Body composition was examined by dual-energy X-ray scan. All participants completed the Cambridge Neuropsychological Test Automated Battery (CANTAB) to assess cognitive performance in three domains: attention, memory, and planning executive function. The Reaction Time (RTI) test was used to assess motor and mental response speeds; the Stockings of Cambridge (SOC) test was used to assess planning executive function. For memory assessment, the Delayed Match to Sample (DMS), Pattern Recognition Memory (PRM), and Spatial Span (SSP) tests were used to assess forced choice recognition memory, visual pattern recognition memory, and working memory capacity, respectively. 36 (36.7%) were morbidly obese, 22 (22.4%) obese, and 23 (23.5%) overweight. Performance on RTI and SOC planning ability were not associated with body mass index (BMI). DMS mean time to correct response, when stimulus is visible or immediately hidden (0 ms delay), was higher by 785 ± 302 ms (milliseconds) ( p =0.011) and 587 ± 259 ms ( p =0.026) in morbidly obese women compared to normal weight women. Memory span length was significantly lower in overweight (5.5 ± 1.3, p =0.008) and obese women (5.6 ± 1.6, p =0.007) compared to normal weight (6.7 ± 0.9). DEXA-assessed body fat (%) showed similar associations as BMI, and latency to correct response on DMS and PRM was positively correlated with percentage of body fat, but not with VO 2 max. In otherwise healthy premenopausal women, obesity did not impact accuracy on cognitive tasks related to attention, memory, or planning executive function, but morbid obesity was associated with higher latency to correct response on memory-specific tasks and lower memory span length.

Anxiety sensitivity, body vigilance and fear of pain.

PubMed

Esteve, M Rosa; Camacho, Laura

2008-06-01

The aim of the present study was to investigate the role of anxiety sensitivity (AS) as a factor relevant to pain and pain persistence. Two studies were conducted to examine the relationship between AS, body vigilance and the experience of pain in non-clinical samples. Study 1 investigated the relationship between AS and body vigilance that was operationalized by the detection latency for innocuous electrical stimuli; trait anxiety and neuroticism were also included as covariates. Results indicated that the high AS group (N=69) presented shorter detection latency than the low AS group (N=70); neuroticism and trait anxiety did not have significant effects on detection latency. Using another sample, Study 2 investigated the relationship between AS, body vigilance, pain tolerance, catastrophizing, and self-reported distress and pain during a cold pressor task. Neuroticism, trait anxiety and fear of pain were included as covariates. Results showed significant differences between high- (N=66) and low- (N=69) AS groups in body vigilance, catastrophizing and tolerance. The covariates neuroticism, trait anxiety and fear of pain did not have any significant effects. No significant differences were found in pain and distress ratings. Results from both studies support the importance of AS in body vigilance and the experience of pain. The theoretical, preventive and clinical implications of these findings are discussed.

Parallel and distributed computation for fault-tolerant object recognition

NASA Technical Reports Server (NTRS)

Wechsler, Harry

1988-01-01

The distributed associative memory (DAM) model is suggested for distributed and fault-tolerant computation as it relates to object recognition tasks. The fault-tolerance is with respect to geometrical distortions (scale and rotation), noisy inputs, occulsion/overlap, and memory faults. An experimental system was developed for fault-tolerant structure recognition which shows the feasibility of such an approach. The approach is futher extended to the problem of multisensory data integration and applied successfully to the recognition of colored polyhedral objects.

Genistein improves 3-NPA-induced memory impairment in ovariectomized rats: impact of its antioxidant, anti-inflammatory and acetylcholinesterase modulatory properties.

PubMed

Menze, Esther T; Esmat, Ahmed; Tadros, Mariane G; Abdel-Naim, Ashraf B; Khalifa, Amani E

2015-01-01

Huntington's disease (HD) is a progressive neurodegenerative disorder. The pre-motor symptomatic stages of the disease are commonly characterized by cognitive problems including memory loss. 3-Nitropropionic acid (3-NPA) is a mitochondrial toxin that produces selective lesions in the brain similar to that of HD and was proven to cause memory impairment in rodents. Phytoestrogens have well-established neuroprotective and memory enhancing effects with fewer side effects in comparison to estrogens. This study investigated the potential neuroprotective and memory enhancing effect of genistein (5, 10 and 20 mg/kg), a phytoestrogen, in ovariectomized rats challenged with 3-NPA (20 mg/kg). These potential effects were compared to those of 17β-estradiol (2.5 mg/kg). Systemic administration of 3-NPA for 4 consecutive days impaired locomotor activity, decreased retention latencies in the passive avoidance task, decreased striatal, cortical and hippocampal ATP levels, increased oxidative stress, acetylcholinesterase (AChE) activity, cycloxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) expressions. Pretreatment with genistein and 17β-estradiol attenuated locomotor hypoactivity, increased retention latencies in the passive avoidance task, increased ATP levels, improved the oxidative stress profile, attenuated the increase in AChE activity and decreased the expression of COX-2 and iNOS. Overall, the higher genistein dose (20 mg/kg) was the most effective. In conclusion, this study suggests neuroprotective and memory enhancing effects for genistein in a rat model of HD. These effects might be attributed to its antioxidant, anti-inflammatory and cholinesterase inhibitory activities.

Cue generation and memory construction in direct and generative autobiographical memory retrieval.

PubMed

Harris, Celia B; O'Connor, Akira R; Sutton, John

2015-05-01

Theories of autobiographical memory emphasise effortful, generative search processes in memory retrieval. However recent research suggests that memories are often retrieved directly, without effortful search. We investigated whether direct and generative retrieval differed in the characteristics of memories recalled, or only in terms of retrieval latency. Participants recalled autobiographical memories in response to cue words. For each memory, they reported whether it was retrieved directly or generatively, rated its visuo-spatial perspective, and judged its accompanying recollective experience. Our results indicated that direct retrieval was commonly reported and was faster than generative retrieval, replicating recent findings. The characteristics of directly retrieved memories differed from generatively retrieved memories: directly retrieved memories had higher field perspective ratings and lower observer perspective ratings. However, retrieval mode did not influence recollective experience. We discuss our findings in terms of cue generation and content construction, and the implication for reconstructive models of autobiographical memory. Copyright © 2015 Elsevier Inc. All rights reserved.

Theoretical implications of quantitative properties of interval timing and probability estimation in mouse and rat.

PubMed

Kheifets, Aaron; Freestone, David; Gallistel, C R

2017-07-01

In three experiments with mice ( Mus musculus ) and rats (Rattus norvigicus), we used a switch paradigm to measure quantitative properties of the interval-timing mechanism. We found that: 1) Rodents adjusted the precision of their timed switches in response to changes in the interval between the short and long feed latencies (the temporal goalposts). 2) The variability in the timing of the switch response was reduced or unchanged in the face of large trial-to-trial random variability in the short and long feed latencies. 3) The adjustment in the distribution of switch latencies in response to changes in the relative frequency of short and long trials was sensitive to the asymmetry in the Kullback-Leibler divergence. The three results suggest that durations are represented with adjustable precision, that they are timed by multiple timers, and that there is a trial-by-trial (episodic) record of feed latencies in memory. © 2017 Society for the Experimental Analysis of Behavior.

Alcohol Attenuates Load-related Activation During a Working Memory Task: Relation to Level of Response to Alcohol

PubMed Central

Paulus, Martin P.; Tapert, Susan F.; Pulido, Carmen; Schuckit, Marc A.

2008-01-01

Background A low level of response to alcohol is a major risk factor for the development of alcohol dependence, but neural correlates of this marker are unclear. Method Ten healthy volunteers were classified by median split on level of response to alcohol and underwent 2 sessions of functional magnetic resonance imaging following ingestion of a moderate dose of alcohol and a placebo. The blood oxygen level–dependent activation to an event-related visual working memory test was examined. Results The subjects exhibited longer response latencies and more errors as a function of increasing working memory load and showed a load-dependent increase in activation in dorsolateral prefrontal cortex, posterior parietal cortex, and visual cortex. Alcohol did not affect performance (errors or response latency), but attenuated the working memory load–dependent activation in the dorsolateral prefrontal cortex. During the placebo condition, individuals with a low level of response to alcohol showed greater activation in dorsolateral prefrontal cortex and posterior parietal cortex than those with a high level of response to alcohol. During the alcohol condition, groups showed similar attenuation of load-dependent brain activation in these regions. Conclusion Low-level responders relative to high-level responders exhibited an increased working memory load–dependent activation in dorsolateral prefrontal cortex and posterior parietal cortex when not exposed to alcohol. This increase in brain response was attenuated in low-level responders after ingesting a moderate dose of alcohol. PMID:16899039

Maternal administration of melatonin prevents spatial learning and memory deficits induced by developmental ethanol and lead co-exposure.

PubMed

Soleimani, Elham; Goudarzi, Iran; Abrari, Kataneh; Lashkarbolouki, Taghi

2017-05-01

Melatonin is a radical scavenger with the ability to remove reactive oxidant species. There is report that co-exposure to lead and ethanol during developmental stages induces learning and memory deficits and oxidative stress. Here, we studied the effect of melatonin, with strong antioxidant properties, on memory deficits induced by lead and ethanol co-exposure and oxidative stress in hippocampus. Pregnant rats in lead and ethanol co-exposure group received lead acetate of 0.2% in distilled drinking water and ethanol (4g/kg) by oral gavages once daily from the 5th day of gestation until weaning. Rats received 10mg/kg melatonin by oral gavages. On postnatal days (PD) 30, rats trained with six trials per day for 6 consecutive days in the water maze. On day 37, a probe test was done and oxidative stress markers in the hippocampus were evaluated. Results demonstrated lead and ethanol co-exposed rats exhibited higher escape latency during training trials and reduced time spent in target quadrant, higher escape location latency in probe trial test and had significantly higher malondialdehyde (MDA) levels, significantly lower superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) activities in the hippocampus. Melatonin treatment could improve memory deficits, antioxidants activity and reduced MDA levels in the hippocampus. We conclude, co-exposure to lead and ethanol impair memory and melatonin can prevent from it by oxidative stress modulation. Copyright © 2017 Elsevier Inc. All rights reserved.

Enhanced zinc consumption causes memory deficits and increased brain levels of zinc

USGS Publications Warehouse

Flinn, J.M.; Hunter, D.; Linkous, D.H.; Lanzirotti, A.; Smith, L.N.; Brightwell, J.; Jones, B.F.

2005-01-01

Zinc deficiency has been shown to impair cognitive functioning, but little work has been done on the effects of elevated zinc. This research examined the effect on memory of raising Sprague-Dawley rats on enhanced levels of zinc (10 ppm ZnCO3; 0.153 mM) in the drinking water for periods of 3 or 9 months, both pre- and postnatally. Controls were raised on lab water. Memory was tested in a series of Morris Water Maze (MWM) experiments, and zinc-treated rats were found to have impairments in both reference and working memory. They were significantly slower to find a stationary platform and showed greater thigmotaxicity, a measure of anxiety. On a working memory task, where the platform was moved each day, zinc-treated animals had longer latencies over both trials and days, swam further from the platform, and showed greater thigmotaxicity. On trials using an Atlantis platform, which remained in one place but was lowered on probe trials, the zinc-treated animals had significantly fewer platform crossings, spent less time in the target quadrant, and did not swim as close to the platform position. They had significantly greater latency on nonprobe trials. Microprobe synchrotron X-ray fluorescence (??SXRF) confirmed that brain zinc levels were increased by adding ZnCO 3 to the drinking water. These data show that long-term dietary administration of zinc can lead to impairments in cognitive function. ?? 2004 Elsevier Inc. All rights reserved.

The effects of vitamin C on hypothyroidism-associated learning and memory impairment in juvenile rats.

PubMed

Beheshti, Farimah; Karimi, Sareh; Vafaee, Farzaneh; Shafei, Mohammad Naser; Sadeghnia, Hamid Reza; Hadjzadeh, Mosa Al Reza; Hosseini, Mahmoud

2017-06-01

In this study the effects of Vitamin C (Vit C) on hypothyroidism-associated learning and memory impairment in juvenile rats was investigated. The pregnant rats were kept in separate cages. After delivery, they were randomly divided into six groups and treated: (1) Control; (2) Propylthiouracil (PTU) which 0.005% PTU in their drinking; (3-5) Propylthiouracil- Vit C groups; besides PTU, dams in these groups received 10, 100 and 500 mg/kg Vit C respectively, (6) one group as a positive control; the intact rats received an effective dose, 100 mg/kg Vit. C. After delivery, the pups were continued to receive the experimental treatments in their drinking water up to 56th day of their life. Ten male offspring of each group were randomly selected and tested in the Morris water maze (MWM) and passive avoidance (PA) which were started at 63th day (one week after stopping of the treatments). Brains were then removed for biochemical measurements. PTU increased time latency and traveled distance during 5 days in MWM while, reduced the spent time in target quadrant in MWM and step-trough latency (STL) in PA. PTU decreased thiol content, superoxide dismutase (SOD) and catalase (CAT) activities in the brain while, increased molondialdehyde (MDA). In MWM test, 10, 100 and 500 mg/kg Vit C reduced time latency and traveled distance without affecting the traveling speed during 5 days. All doses of Vit C increased the spent time in target quadrant in probe trail of MWM and also increased STL in PA test. Vit C increased thiol, SOD and CAT in the brain tissues while, reduced MDA. Results of present study confirmed the beneficial effects of Vit C on learning and memory. It also demonstrated that Vit C has protective effects on hypothyroidism-associated learning and memory impairment in juvenile rats which might be elucidated by the antioxidative effects.

Anti-proliferative therapy for HIV cure: a compound interest approach.

PubMed

Reeves, Daniel B; Duke, Elizabeth R; Hughes, Sean M; Prlic, Martin; Hladik, Florian; Schiffer, Joshua T

2017-06-21

In the era of antiretroviral therapy (ART), HIV-1 infection is no longer tantamount to early death. Yet the benefits of treatment are available only to those who can access, afford, and tolerate taking daily pills. True cure is challenged by HIV latency, the ability of chromosomally integrated virus to persist within memory CD4 + T cells in a non-replicative state and activate when ART is discontinued. Using a mathematical model of HIV dynamics, we demonstrate that treatment strategies offering modest but continual enhancement of reservoir clearance rates result in faster cure than abrupt, one-time reductions in reservoir size. We frame this concept in terms of compounding interest: small changes in interest rate drastically improve returns over time. On ART, latent cell proliferation rates are orders of magnitude larger than activation and new infection rates. Contingent on subtypes of cells that may make up the reservoir and their respective proliferation rates, our model predicts that coupling clinically available, anti-proliferative therapies with ART could result in functional cure within 2-10 years rather than several decades on ART alone.

The solution of large multi-dimensional Poisson problems

NASA Technical Reports Server (NTRS)

Stone, H. S.

1974-01-01

The Buneman algorithm for solving Poisson problems can be adapted to solve large Poisson problems on computers with a rotating drum memory so that the computation is done with very little time lost due to rotational latency of the drum.

Beneficial effects of Urtica dioica on scopolamine-induced memory impairment in rats: protection against acetylcholinesterase activity and neuronal oxidative damage.

PubMed

Ghasemi, Simagol; Moradzadeh, Malihe; Hosseini, Mahmoud; Beheshti, Farimah; Sadeghnia, Hamid Reza

2018-05-10

This study was conducted to investigate protective effects of Urtica dioica extract on acetylcholinesterase (AChE) activity and the oxidative damage of brain tissues in scopolamine-induced memory impairment model. The rats were treated with (1) saline (control), (2) scopolamine, and (3-5) the plant extract (20, 50, or 100 mg/kg) before scopolamine. The traveled distance and the latency to find the platform in Morris water maze (MWM) by scopolamine-treated group were longer while the time spent in target quadrant was shorter than those of the control. Scopolamine decreased the latency to enter the dark in passive avoidance test. Besides, it also increased AChE activity and malondialdehyde (MDA) concentration in the hippocampal and cortical tissues while decreased thiols content and superoxide dismutase (SOD) and catalase (CAT) activities in the brain (p < 0.01-p <0.001). Treatment by the extract reversed all the effects of scopolamine (p < 0.05-p <0.001). According to the results of present study, the beneficial effects of U. dioica on memory can be attributed to its protective effects on oxidative damage of brain tissue and AChE activity.

Low latency, high bandwidth data communications between compute nodes in a parallel computer

DOEpatents

Archer, Charles J.; Blocksome, Michael A.; Ratterman, Joseph D.; Smith, Brian E.

2010-11-02

Methods, parallel computers, and computer program products are disclosed for low latency, high bandwidth data communications between compute nodes in a parallel computer. Embodiments include receiving, by an origin direct memory access (`DMA`) engine of an origin compute node, data for transfer to a target compute node; sending, by the origin DMA engine of the origin compute node to a target DMA engine on the target compute node, a request to send (`RTS`) message; transferring, by the origin DMA engine, a predetermined portion of the data to the target compute node using memory FIFO operation; determining, by the origin DMA engine whether an acknowledgement of the RTS message has been received from the target DMA engine; if the an acknowledgement of the RTS message has not been received, transferring, by the origin DMA engine, another predetermined portion of the data to the target compute node using a memory FIFO operation; and if the acknowledgement of the RTS message has been received by the origin DMA engine, transferring, by the origin DMA engine, any remaining portion of the data to the target compute node using a direct put operation.

The contribution of the androgen receptor (AR) in human spatial learning and memory: A study in women with complete androgen insensitivity syndrome (CAIS).

PubMed

Mueller, S C; Verwilst, T; Van Branteghem, A; T'Sjoen, G; Cools, M

2016-02-01

Few studies have examined the impact of androgen insensitivity on human spatial learning and memory. In the present study, we tested 11 women with complete androgen insensitivity syndrome (CAIS), a rare genetic disorder characterized by complete absence of AR activity, and compared their performance against 20 comparison males and 19 comparison females on a virtual analog of the Morris Water Maze task. The results replicated a main sex effect showing that men relative to women were faster in finding the hidden platform and had reduced heading error. Furthermore, findings indicated that mean performance of women with CAIS was between control women and control men, though the differences were not statistically significant. Effect size estimates (and corresponding confidence intervals) of spatial learning trials showed little difference between women with CAIS and control women but CAIS women differed from men, but not women, on two variables, latency to find the platform and first-move latency. No differences between groups were present during visible platform trials or the probe trial, a measure of spatial memory. Moreover, groups also did not differ on estimates of IQ and variability of performance. The findings are discussed in relation to androgen insensitivity in human spatial learning and memory. Copyright © 2015 Elsevier Inc. All rights reserved.

Preliminary evidence that abscisic acid improves spatial memory in rats.

PubMed

Qi, Cong-Cong; Ge, Jin-Fang; Zhou, Jiang-Ning

2015-02-01

Abscisic acid (ABA) is a crucial phytohormone that exists in a wide range of animals, including humans, and has multiple bioactivities. As direct derivatives of carotenoids, ABA and retinoic acid (RA) share similar molecular structures, and RA has been reported to improve spatial memory in rodents. To explore the potential effects of ABA on spatial learning and memory in rodents, 20mg/kg ABA was administered to young rats for 6weeks, and its effects on behaviour performance were evaluated through a series of behavioural tests. ABA pharmacokinetic analysis revealed that the exogenous ABA was distributed widely in the rat brain, characterised by rapid absorption and slow elimination. The behavioural tests showed that ABA increased both the duration spent in the target quadrant and the frequency it was entered in the probe test of the Morris water maze (MWM) and decreased the latency to locate the target quadrant. Moreover, ABA decreased the latency to enter the novel arm in the Y-maze test, accompanied by increases in the total entries and distance travelled in the three arms. However, there were no significant differences between the ABA-treated and control rats in the open field test and elevated plus-maze test. These results preliminarily indicate that ABA improves spatial memory in MWM and exploratory activity in Y-maze in young rats. Copyright © 2014 Elsevier Inc. All rights reserved.

High-performance parallel processors based on star-coupled wavelength division multiplexing optical interconnects

DOEpatents

Deri, Robert J.; DeGroot, Anthony J.; Haigh, Ronald E.

2002-01-01

As the performance of individual elements within parallel processing systems increases, increased communication capability between distributed processor and memory elements is required. There is great interest in using fiber optics to improve interconnect communication beyond that attainable using electronic technology. Several groups have considered WDM, star-coupled optical interconnects. The invention uses a fiber optic transceiver to provide low latency, high bandwidth channels for such interconnects using a robust multimode fiber technology. Instruction-level simulation is used to quantify the bandwidth, latency, and concurrency required for such interconnects to scale to 256 nodes, each operating at 1 GFLOPS performance. Performance scales have been shown to .apprxeq.100 GFLOPS for scientific application kernels using a small number of wavelengths (8 to 32), only one wavelength received per node, and achievable optoelectronic bandwidth and latency.

Characterization of the faulted behavior of digital computers and fault tolerant systems

NASA Technical Reports Server (NTRS)

Bavuso, Salvatore J.; Miner, Paul S.

1989-01-01

A development status evaluation is presented for efforts conducted at NASA-Langley since 1977, toward the characterization of the latent fault in digital fault-tolerant systems. Attention is given to the practical, high speed, generalized gate-level logic system simulator developed, as well as to the validation methodology used for the simulator, on the basis of faultable software and hardware simulations employing a prototype MIL-STD-1750A processor. After validation, latency tests will be performed.

Effect of manipulated state aggression on pain tolerance.

PubMed

Stephens, Richard; Allsop, Claire

2012-08-01

Swearing produces a pain lessening (hypoalgesic) effect for many people; an emotional response may be the underlying mechanism. In this paper, the role of manipulated state aggression on pain tolerance and pain perception is assessed. In a repeated-measures design, pain outcomes were assessed in participants asked to play for 10 minutes a first-person shooter video game vs a golf video game. Sex differences were explored. After playing the first-person shooter video game, aggressive cognitions, aggressive affect, heart rate, and cold pressor latency were increased, and pain perception was decreased. These data indicate that people become more pain tolerant with raised state aggression and support our theory that raised pain tolerance from swearing occurs via an emotional response.

Egocentric and nonegocentric coding in memory for spatial layout: Evidence from scene recognition

PubMed Central

2005-01-01

Much contemporary research has suggested that memories for spatial layout are stored with a preferred orientation. The present paper examines whether spatial memories are also stored with a preferred viewpoint position. Participants viewed images of an arrangement of objects taken from a single viewpoint, and were subsequently tested on their ability to recognize the arrangement from novel viewpoints that had been translated in either the lateral or depth dimension. Lateral and forward displacements of the viewpoint resulted in increasing response latencies and errors. Backward displacement showed no such effect, nor did lateral translation that resulted in a centered “canonical” view of the arrangement. These results further constrain the specificity of spatial memory, while also providing some evidence that nonegocentric spatial information is coded in memory. PMID:16933759

Chronic cyanidin-3-glucoside administration improves short-term spatial recognition memory but not passive avoidance learning and memory in streptozotocin-diabetic rats.

PubMed

Nasri, Sima; Roghani, Mehrdad; Baluchnejadmojarad, Tourandokht; Balvardi, Mahboubeh; Rabani, Tahereh

2012-08-01

This research study was conducted to evaluate the efficacy of chronic cyanidin-3-glucoside (C3G) on alleviation of learning and memory deficits in diabetic rats as a result of the observed antidiabetic and antioxidant activity of C3G. Male Wistar rats were divided into control, diabetic, C3G-treated-control and -diabetic groups. The C3G was administered i.p. at a dose of 10 mg/kg on alternate days for eight weeks. For evaluation of learning and memory, initial latency (IL) and step-through latency (STL) were determined at the end of study using passive avoidance test. Meanwhile, spatial recognition memory was assessed as alternation in the Y-maze task. Oxidative stress markers in brain tissue were also measured. It was found that the alternation score of the diabetic rats was lower than that of control (p < 0.01) and C3G-treated diabetic rats showed a higher alternation score as compared to diabetic group (p < 0.05). Diabetic rats also developed a significant impairment in retention and recall in passive avoidance test (p < 0.01) and C3G treatment of diabetic rats did not produce any significant improvement. Meanwhile, increased level of malondialdehyde (MDA) in diabetic rats was significantly reduced following C3G treatment (p < 0.05). Taken together, chronic C3G could improve short-term spatial recognition memory disturbance in the Y-maze test but not retention and recall capability in passive avoidance test in STZ-diabetic rats. Copyright © 2012 John Wiley & Sons, Ltd.

Beneficial effects of garlic on learning and memory deficits and brain tissue damages induced by lead exposure during juvenile rat growth is comparable to the effect of ascorbic acid.

PubMed

Ghasemi, Simagol; Hosseini, Mahmoud; Feizpour, Azadeh; Alipour, Fatemeh; Sadeghi, Akram; Vafaee, Farzaneh; Mohammadpour, Toktam; Soukhtanloo, Mohammad; Ebrahimzadeh Bideskan, Alireza; Beheshti, Farimah

2017-04-01

The neuroprotective effects of both garlic and ascorbic acid (AA) have been documented. In this study the effects of garlic and ascorbic acid on memory deficits and brain tissue oxidative damages induced by lead exposure was investigated. The juvenile rats were divided and treated: (1) Control, (2) Lead (lead acetate in drinking water, 8 weeks), (3) Lead - Ascorbic Acid (Lead-AA), (4)  Lead - Garlic (100 mg/kg, daily, gavage) (Lead-Gar). In Morris water maze (MWM), the escape latency and traveled path in the Lead group were significantly higher while, the time spent in the target quadrant (Q1) was lower than Control. Both Lead-Gar and Lead-AA groups spent more times in Q1than to lead group. There were no significant differences in swimming speed between the groups. In passive avoidance (PA) test, the time latency for entering the dark compartment by Lead group was lower than Control. Treatment of the animals by AA and garlic significantly increased the time latency. In Lead group, the total thiol concentration in brain tissues was significantly lower while, MDA was higher than Control. Treatment by both garlic and AA increased total thiol concentrations and decreased MDA. Both garlic and AA decreased the lead content of brain tissues. It is suggested that treatment with garlic attenuates the learning and memory impairments due to lead exposure during juvenile rat growth which is comparable to AA. The possible mechanism may be due to its protective effects against brain tissues oxidative damage as well the lowering effects of brain lead content.

NAND FLASH Radiation Tolerant Intelligent Memory Stack (RTIMS FLASH)

NASA Astrophysics Data System (ADS)

Sellier, Charles; Wang, Pierre

2014-08-01

The NAND Flash Radiation Tolerant and Intelligent Memory Stack (RTIMS FLASH) is a User's Friendly, Plug-and- Play and Radiation Protected high density NAND Flash Memory. It provides a very high density, radiation hardened by design and non-volatile memory module suitable for all space applications such as commercial or scientific geo-stationary missions, earth observation, navigation, manned space vehicles and deep space scientific exploration. The Intelligent Memory Module embeds a very high density of non-volatile NAND Flash memory and one Intelligent Flash Memory Controller (FMC). The FMC provides the module with a full protection against the radiation effects such as SEL, SEFI and SEU. It's also granting the module with bad block immunity as well as high level service functions that will benefit to the user's applications.

Post-manufacturing, 17-times acceptable raw bit error rate enhancement, dynamic codeword transition ECC scheme for highly reliable solid-state drives, SSDs

NASA Astrophysics Data System (ADS)

Tanakamaru, Shuhei; Fukuda, Mayumi; Higuchi, Kazuhide; Esumi, Atsushi; Ito, Mitsuyoshi; Li, Kai; Takeuchi, Ken

2011-04-01

A dynamic codeword transition ECC scheme is proposed for highly reliable solid-state drives, SSDs. By monitoring the error number or the write/erase cycles, the ECC codeword dynamically increases from 512 Byte (+parity) to 1 KByte, 2 KByte, 4 KByte…32 KByte. The proposed ECC with a larger codeword decreases the failure rate after ECC. As a result, the acceptable raw bit error rate, BER, before ECC is enhanced. Assuming a NAND Flash memory which requires 8-bit correction in 512 Byte codeword ECC, a 17-times higher acceptable raw BER than the conventional fixed 512 Byte codeword ECC is realized for the mobile phone application without an interleaving. For the MP3 player, digital-still camera and high-speed memory card applications with a dual channel interleaving, 15-times higher acceptable raw BER is achieved. Finally, for the SSD application with 8 channel interleaving, 13-times higher acceptable raw BER is realized. Because the ratio of the user data to the parity bits is the same in each ECC codeword, no additional memory area is required. Note that the reliability of SSD is improved after the manufacturing without cost penalty. Compared with the conventional ECC with the fixed large 32 KByte codeword, the proposed scheme achieves a lower power consumption by introducing the "best-effort" type operation. In the proposed scheme, during the most of the lifetime of SSD, a weak ECC with a shorter codeword such as 512 Byte (+parity), 1 KByte and 2 KByte is used and 98% lower power consumption is realized. At the life-end of SSD, a strong ECC with a 32 KByte codeword is used and the highly reliable operation is achieved. The random read performance is also discussed. The random read performance is estimated by the latency. The latency is below 1.5 ms for ECC codeword up to 32 KByte. This latency is below the average latency of 15,000 rpm HDD, 2 ms.

Relation between language, audio-vocal psycholinguistic abilities and P300 in children having specific language impairment.

PubMed

Shaheen, Elham Ahmed; Shohdy, Sahar Saad; Abd Al Raouf, Mahmoud; Mohamed El Abd, Shereen; Abd Elhamid, Asmss

2011-09-01

Specific language impairment is a relatively common developmental condition in which a child fails to develop language at the typical rate despite normal general intellectual abilities, adequate exposure to language, and in the absence of hearing impairments, or neurological or psychiatric disorders. There is much controversy about the extent to which the auditory processing deficits are important in the genesis specific language impairment. The objective of this paper is to assess the higher cortical functions in children with specific language impairment, through assessing neurophysiological changes in order to correlate the results with the clinical picture of the patients to choose the proper rehabilitation training program. This study was carried out on 40 children diagnosed to have specific language impairment and 20 normal children as a control group. All children were subjected to the assessment protocol applied in Kasr El-Aini hospital. They were also subjected to a language test (receptive, expressive and total language items), the audio-vocal items of Illinois test of psycholinguistic (auditory reception, auditory association, verbal expression, grammatical closure, auditory sequential memory and sound blending) as well as audiological assessment that included peripheral audiological and P300 amplitude and latency assessment. The results revealed a highly significant difference in P300 amplitude and latency between specific language impairment group and control group. There is also strong correlations between P300 latency and the grammatical closure, auditory sequential memory and sound blending, while significant correlation between the P300 amplitude and auditory association and verbal expression. Children with specific language impairment, in spite of the normal peripheral hearing, have evidence of cognitive and central auditory processing defects as evidenced by P300 auditory event related potential in the form of prolonged latency which indicate a slow rate of processing and defective memory as evidenced by small amplitude. These findings affect cognitive and language development in specific language impairment children and should be considered during planning the intervention program. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Effects of a dragonfly (Anax i.) homeopathic remedy on learning, memory and cell morphology in mice.

PubMed

Mutlu, Oguz; Ulak, Guner; Kokturk, Sibel; Komsuoglu Celikyurt, Ipek; Tanyeri, Pelin; Akar, Furuzan; Erden, Faruk

2016-02-01

Homeopathy is a form of alternative medicine in which uses highly diluted preparations that are believed to cause healthy people to exhibit symptoms similar to those exhibited by patients. The aim of this study was to investigate the effects of dragonfly (Anax imperator, Anax i.) on learning and memory in naive mice using the Morris water maze (MWM) test; moreover, the effects of dragonfly on MK-801-induced cognitive dysfunction were evaluated. Male balb-c mice were treated with dragonfly (30C and 200C) or MK-801 (0.2 mg/kg) alone or concurrently (n = 10). Dragonfly (D) and MK-801 were administered subchronically for 6 days intraperitoneally 60 min and 30 min, respectively, before the daily performance of the MWM test. This study revealed that in the familiarization session and first session of the MWM test, Anax i. D30 significantly decreased escape latency compared to the control group, although MK-801, D30 and D200 significantly increased escape latency at the end of five acquisition sessions. Anax i. combined with dizocilpine maleate (MK-801) also significantly decreased escape latency in the familiarization session and first session of the MWM test, although this combination increased escape latency compared to the MK-801 alone group at the end of the test. Time spent in escape platform's quadrant in the probe trial significantly decreased while mean distance to platform significantly increased in MK-801, D30 and D200 groups. In the MWM test, Anax i. combined with MK-801 significantly decreased speed of the animals compared to the MK-801 alone group. General cell morphology was disturbed in the MK-801 group while D30 and D200 seemed to improve cell damage in the MK-801 group. These results suggest that the homeopathic Anax i. can impair learning acquisition and reference memory, and it has beneficial effects on disturbed cell morphology. Copyright © 2015 The Faculty of Homeopathy. Published by Elsevier Ltd. All rights reserved.

Innate immune memory in the brain shapes neurological disease hallmarks.

PubMed

Wendeln, Ann-Christin; Degenhardt, Karoline; Kaurani, Lalit; Gertig, Michael; Ulas, Thomas; Jain, Gaurav; Wagner, Jessica; Häsler, Lisa M; Wild, Katleen; Skodras, Angelos; Blank, Thomas; Staszewski, Ori; Datta, Moumita; Centeno, Tonatiuh Pena; Capece, Vincenzo; Islam, Md Rezaul; Kerimoglu, Cemil; Staufenbiel, Matthias; Schultze, Joachim L; Beyer, Marc; Prinz, Marco; Jucker, Mathias; Fischer, André; Neher, Jonas J

2018-04-01

Innate immune memory is a vital mechanism of myeloid cell plasticity that occurs in response to environmental stimuli and alters subsequent immune responses. Two types of immunological imprinting can be distinguished-training and tolerance. These are epigenetically mediated and enhance or suppress subsequent inflammation, respectively. Whether immune memory occurs in tissue-resident macrophages in vivo and how it may affect pathology remains largely unknown. Here we demonstrate that peripherally applied inflammatory stimuli induce acute immune training and tolerance in the brain and lead to differential epigenetic reprogramming of brain-resident macrophages (microglia) that persists for at least six months. Strikingly, in a mouse model of Alzheimer's pathology, immune training exacerbates cerebral β-amyloidosis and immune tolerance alleviates it; similarly, peripheral immune stimulation modifies pathological features after stroke. Our results identify immune memory in the brain as an important modifier of neuropathology.

Effects of Methyl Jasmonate on Acute Stress Responses in Mice Subjected to Forced Swim and Anoxic Tests

PubMed Central

Aluko, Oritoke M.; Umukoro, Solomon; Annafi, Olajide S.; Adewole, Folashade A.; Omorogbe, Osarume

2015-01-01

Methyl jasmonate (MJ) is an anti-stress hormone released by plants in response to external stressors and aids adaptation to stress. In this study, we evaluated the anti-stress activity of MJ using the forced swim endurance test (FSET) and anoxic tolerance test in mice. Male Swiss mice were given MJ (25–100 mg/kg, i.p) 30 min before the FSET and anoxic test were carried out. The first occurrence of immobility, duration of immobility, time spent in active swimming, and latency to exhaustion were assessed in the FSET. The onset to anoxic convulsion was measured in the anoxic tolerance test. MJ significantly (p < 0.05) delayed the first occurrence of immobility and shortened the period of immobility, which indicates anti-stress property. MJ also increased the time spent in active swimming and prolonged the latency to exhaustion, which further suggests anti-stress activity. In addition, it also exhibited anti-stress property as evidenced by prolonged latency to first appearance of anoxic convulsions. The results of this study suggest that MJ demonstrated anti-stress activity and may be useful as an energizer in times of body weakness or exhaustion. Although more studies are necessary before concluding on how MJ exerts its anti-stress activity, the present data suggest an action similar to adaptogens in boosting energy and resilience in the face of stress. PMID:26839844

Working memory and planning during sentence production.

PubMed

Martin, Randi C; Yan, Hao; Schnur, Tatiana T

2014-10-01

Speakers retrieve conceptual, syntactic and lexical information in advance of articulation during sentence production. What type of working memory (WM) store is used to hold the planned information before speaking? To address this question, we measured onset latencies when subjects produced sentences that began with either a complex or a simple initial noun phrase, while holding semantic, phonological or spatial information in WM. Although we found that subjects had longer onset latencies for sentences beginning with a complex noun phrase, showing a phrasal scope of planning, the magnitude of this complexity effect was not affected by any type of WM load. However, subjects made more syntactic errors (but not lexical errors) for sentences beginning with a complex noun phrase, suggesting that advance planning for these phrases occurs at a syntactic rather than lexical-semantic level, which may account for the lack of effect with various types of WM load in the current study. Copyright © 2014 Elsevier B.V. All rights reserved.

Evaluation of nootropic potential of Ocimum sanctum Linn. in mice.

PubMed

Joshi, Hanumanthachar; Parle, Milind

2006-02-01

Dementia is one of the age related mental problems and a characteristic symptom of various neurodegenerative disorders including Alzheimer's disease. Certain drugs like diazepam, barbiturates and alcohol disrupt learning and memory in animals and man. However, a new class of drugs known as nootropic agents is now used in situations where there is organic disorder in learning abilities. The present work was undertaken to assess the potential of O. sanctum extract as a nootropic and anti-amnesic agent in mice. Aqueous extract of dried whole plant of O. sanctum ameliorated the amnesic effect of scopolamine (0.4 mg/kg), diazepam (1 mg/kg) and aging induced memory deficits in mice. Elevated plus maze and passive avoidance paradigm served as the exteroceptive behavioral models. O. sanctum extract decreased transfer latency and increased step down latency, when compared to control (piracetam treated), scopolamine and aged groups of mice significantly. O. sanctum preparations could of beneficial in the treatment of cognitive disorders such as dementia and Alzheimer's disease.

Decreased sexual motivation and heightened anxiety in male Long-Evans rats are correlated with the memory for a traumatic event.

PubMed

Hawley, Wayne R; Grissom, Elin M; Belkin, Mark N; James, Thomas F; Dohanich, Gary P

2013-05-01

Individuals suffering from posttraumatic stress disorder (PTSD) frequently report disturbances in sexual functioning in addition to alterations in their affective behaviors. Notably, maladaptive cognitions and dysfunctional behaviors are perpetuated by the emergence of the intrusive thoughts that characterize the disorder. In rats, reminders of a traumatic event designed to simulate intrusive thoughts are associated with impairments in affective, social, and sexual behaviors. The current study examined the relationship between the memory for a traumatic event and changes in sexual and affective behaviors in male Long-Evans rats (N = 36). The trauma featured a combination stressor consisting of simultaneous exposure to a footshock and the odor of soiled cat litter. Memory for the trauma was reactivated by re-exposures to the context of the trauma in the absence of stressors and confirmed by assessing the percentage of time spent freezing. Following the second and final reminder, traumatized males exhibited reduced sexual motivation and increased anxiety, signified by longer latencies to achieve their first mount on a post-stress test of sexual behavior, and longer latencies to begin feeding in a novel environment, respectively. Correlational analyses revealed that decreased sexual motivation and heightened anxiety were predicted by the memory for the trauma as indicated by the time spent freezing during the re-exposures. The findings from the current study have implications for understanding the relationship between stress and sexual functioning and indicate that the impairments in sexual behavior that often occur in individuals with PTSD may be impacted by their memory for the trauma.

48. Associations Between Electrophysiological Measures of Selective Attention and Neurocognitive Measures of Working Memory and Attention in Antipsychotic-Naive, First-Episode Schizophrenia Patients

PubMed Central

Kruiper, Caitlyn; Fagerlund, Birgitte; Nielsen, Mette Ø.; Düring, Signe; Jensen, Maria H.; Ebdrup, Bjørn H.; Glenthøj, Birte Y.; Oranje, Bob

2017-01-01

Abstract Background: Deficits in attention and working memory are already present in early stages of schizophrenia. The P3a and b event related brain potentials (ERPs) are believed to underlie processes of attention and working memory, but, only limited research has been performed on the associations between these psychophysiological and cognitive deficits, particularly in the early stages of schizophrenia. We aimed to investigate associations between P3a and P3b amplitudes and measures of attention and working memory in a large cohort of antipsychotic-naive, first-episode schizophrenia patients (AN-FES) and age and sex-matched healthy controls (HC). Methods: Eighty-three AN-FES patients and 108 HC, matched for age and gender, were assessed for their P3a and b amplitude and latency with the selective attention paradigm from the Copenhagen Psychophysiological Test Battery (CPTB). In addition, the Spatial Working Memory (SWM) and Rapid Visual Information Processing test (RVP) from the Cambridge Neuropsychological Test Automated Battery (CANTAB) were used to assess working memory and attention. Outcome measure for the SWM was Strategy, wherein a low score represents a more effective strategy. For the RVP, we used the A’ measure as outcome. This measure represents how well the participant is able to detect target sequences. Results: P3a and P3b amplitudes were significantly reduced in our AN-FES patients compared to HC. In addition, the P3a peak latency was earlier in the AN-FES patients than in HC, while P3b latency did not differ between the groups. Furthermore, AN-FES patients scored significantly lower on the SWM task and the RVP compared to HC. A positive association was found between RVP and P3b in our total group. However, this effect disappeared when split into the two subgroups. In contrast, SWM was positively associated with P3b in HC, while this effect was neither present in AN-FES nor in the total group. Conclusion: Our results provide evidence for P3a and P3b amplitude reductions as well as neurocognitive deficits in AN-FES patients compared to age and gender matched HC. This supports previous data that electrophysiological and neurocognitive deficits already exist in early stages of schizophrenia, and are not due to use of antipsychotics. Our data support significant yet rather weak associations between P3b amplitude and both working memory and attention, although the association between working memory and P3b was only found in HC and not in AN-FES.

Continuous recognition of spatial and nonspatial stimuli in hippocampal-lesioned rats.

PubMed

Jackson-Smith, P; Kesner, R P; Chiba, A A

1993-03-01

The present experiments compared the performance of hippocampal-lesioned rats to control rats on a spatial continuous recognition task and an analogous nonspatial task with similar processing demands. Daily sessions for Experiment 1 involved sequential presentation of individual arms on a 12-arm radial maze. Each arm contained a Froot Loop reinforcement the first time it was presented, and latency to traverse the arm was measured. A subset of the arms were repeated, but did not contain reinforcement. Repeated arms were presented with lags ranging from 0 to 6 (0 to 6 different arm presentations occurred between the first and the repeated presentation). Difference scores were computed by subtracting the latency on first presentations from the latency on repeated presentations, and these scores were high in all rats prior to surgery, with a decreasing function across lag. There were no differences in performance following cortical control or sham surgery. However, there was a total deficit in performance following large electrolytic lesions of the hippocampus. The second experiment employed the same continuous recognition memory procedure, but used three-dimensional visual objects (toys, junk items, etc., in various shapes, sizes, and textures) as stimuli on a flat runway. As in Experiment 1, the stimuli were presented successively and latency to run to and move the object was measured. Objects were repeated with lags ranging from 0 to 4. Performance on this task following surgery did not differ from performance prior to surgery for either the control group or the hippocampal lesion group. These results provide support for Kesner's attribute model of hippocampal function in that the hippocampus is assumed to mediate data-based memory for spatial locations, but not three-dimensional visual objects.

Auditory event-related potentials in subcortical vascular cognitive impairment and in Alzheimer's disease.

PubMed

Muscoso, E G; Costanzo, E; Daniele, O; Maugeri, D; Natale, E; Caravaglios, G

2006-11-01

Few studies exist on ERPs and patients with subcortical vascular cognitive impairment (SVCI). This latter is a quite homogeneous subtype of vascular dementia whose cognitive profile is quite different from that of Alzheimer disease (AD). The present study aims at comparing the ERPs profile both in patients with SVCI and in patients with AD. ERPs and psychometric tests were collected from 39 healthy elderly controls, 51 patients with SVCI and 43 patients with AD. Subjects mentally count high pitched target tones that were randomly intermixed with low pitched frequent tones. We measured ERPs latencies (N1, P2, N2 and P3), and interpeak latencies (N1-P3, N1-P2, N1-N2). Grand averaged potentials in SVCI showed a significant increase of P3 latency. AD patients showed a prolongation of N1, P2, N2, P3 latencies. As far as interpeak latencies are concerned, SVCI patients showed a significant prolongation of N1-P3, AD patients had a significant increase of N1-N2, and N1-P3 intervals. When all patients were considered as a single group, correlation of neuropsychological tests scores showed a significant negative relationship between P300 latency and, respectively, Mini Mental Status Examination, auditive and visual span forward. In both groups, ERPs latency sensitivity, was low, whilst specificity values were quite high. Our finding suggest that these two dementing diseases have different electrophysiologic features that may be related to their specific underlying pathogenetic mechanism; in particular, we hypothesise that, differently from AD, P300 latency prolongation characterizes the early stage of SVCI. So, this ERPs approach could be helpful to detect early alterations of the attentional/working-memory functions in patients with subcortical ischaemic vascular disease.

SUMC fault tolerant computer system

NASA Technical Reports Server (NTRS)

1980-01-01

The results of the trade studies are presented. These trades cover: establishing the basic configuration, establishing the CPU/memory configuration, establishing an approach to crosstrapping interfaces, defining the requirements of the redundancy management unit (RMU), establishing a spare plane switching strategy for the fault-tolerant memory (FTM), and identifying the most cost effective way of extending the memory addressing capability beyond the 64 K-bytes (K=1024) of SUMC-II B. The results of the design are compiled in Contract End Item (CEI) Specification for the NASA Standard Spacecraft Computer II (NSSC-II), IBM 7934507. The implementation of the FTM and memory address expansion.

Late effects of radiation on the lumbar spinal cord of guinea pigs: Re-treatment tolerance

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

Mason, K.A.; Withers, H.R.; Chiang, Chi-Shiun

Using a guinea pig model of lumbar myelopathy, various factors affecting the tolerance of spinal cord to irradiation were assessed: (a) extent of initial injury; (b) time interval between priming and test doses; and (c) animal age at the time of initial radiation treatment. A 3 cm section of lumbar spinal cord of guinea pigs was irradiated with fractionated doses of 4.5 Gy gamma rays given as 9 fractions per week. Guinea pigs were primed with 9 x 4.5 Gy in 7 days which is 60% of the ED[sub 50] for a continuous course of treatment. After 28 or 40more » weeks, animal were retreated with 6-14 fractions of 4.5 Gy. Animals were observed for 2 years following the priming dose and both the incidence and latency of myelopathy recorded. Young adult guinea pigs (8 wk old) showed both a decreased radiation tolerance and latency compared to old individuals (40 wk old). At 28 or 40 wk after 9 x 4.5 Gy, only about 8% of the initial injury was remembered in young adult guinea pigs. The amount of residual injury was dependent on the initial damage as a proportion of the tolerance dose. The spinal cord shows a greater capacity for long-term recovery than generally appreciated and re-treatment doses clinically prescribed may be lower than necessary. 8 refs., 3 figs., 2 tabs.« less

Saccade latency reveals episodic representation of object color.

PubMed

Gordon, Robert D

2014-08-01

While previous studies suggest that identity, but not color, plays a role in episodic object representation, such studies have typically used tasks in which only identity is relevant, raising the possibility that the results reflect task demands, rather than the general principles that underlie object representation. In the present study, participants viewed a preview display containing one (Experiments 1 and 2) or two (Experiment 3) letters, then viewed a target display containing a single letter, in either the same or a different location. Participants executed an immediate saccade to fixate the target; saccade latency served as the dependent variable. In all experiments, saccade latencies were longer to fixate a target appearing in its previewed location, consistent with a bias to attend to new objects rather than to objects for which episodic representations are being maintained in visual working memory. The results of Experiment 3 further demonstrate, however, that changing target color eliminates these latency differences. The results suggest that color and identity are part of episodic representation even when not task relevant and that examining biases in saccade execution may be a useful approach to studying episodic representation.

Controlled replication: reduce the capacity occupied by redundant replicas in tiled chip multiprocessors

NASA Astrophysics Data System (ADS)

Li, Hao; Xie, Lunguo

2013-03-01

The design of cache system for Chip Multiprocessor (CMP) face many challenges because future CMPs will have more cores and greater on-chip cache capacity. There are two base design schemes about L2 cache: private scheme in which each L2 slice is treated as a private L2 cache and shared scheme in which all L2 slices are treated as a large L2 cache shared by all cores. Private caches provide the lowest hit latency but reduce the total effective cache capacity. A shared L2 cache increases the effective cache capacity but has long hit latencies when data is on a remote tile. This paper present a new Controlled Replication (CR) policy to reduce the capacities occupied by redundant shared replicas. the new CR policy increases the effective capacity than victim replication scheme and has lower hit latency than shared scheme. We evaluate the various schemes using full-system simulation of parallel applications. Results show that CR reduces the average memory access latency of shared scheme by an average of 13%, providing better overall performance than victim replication and shared schemes.

In-memory interconnect protocol configuration registers

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

Cheng, Kevin Y.; Roberts, David A.

Systems, apparatuses, and methods for moving the interconnect protocol configuration registers into the main memory space of a node. The region of memory used for storing the interconnect protocol configuration registers may also be made cacheable to reduce the latency of accesses to the interconnect protocol configuration registers. Interconnect protocol configuration registers which are used during a startup routine may be prefetched into the host's cache to make the startup routine more efficient. The interconnect protocol configuration registers for various interconnect protocols may include one or more of device capability tables, memory-side statistics (e.g., to support two-level memory data mappingmore » decisions), advanced memory and interconnect features such as repair resources and routing tables, prefetching hints, error correcting code (ECC) bits, lists of device capabilities, set and store base address, capability, device ID, status, configuration, capabilities, and other settings.« less

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

Bender, Michael A.; Berry, Jonathan W.; Hammond, Simon D.

A challenge in computer architecture is that processors often cannot be fed data from DRAM as fast as CPUs can consume it. Therefore, many applications are memory-bandwidth bound. With this motivation and the realization that traditional architectures (with all DRAM reachable only via bus) are insufficient to feed groups of modern processing units, vendors have introduced a variety of non-DDR 3D memory technologies (Hybrid Memory Cube (HMC),Wide I/O 2, High Bandwidth Memory (HBM)). These offer higher bandwidth and lower power by stacking DRAM chips on the processor or nearby on a silicon interposer. We will call these solutions “near-memory,” andmore » if user-addressable, “scratchpad.” High-performance systems on the market now offer two levels of main memory: near-memory on package and traditional DRAM further away. In the near term we expect the latencies near-memory and DRAM to be similar. Here, it is natural to think of near-memory as another module on the DRAM level of the memory hierarchy. Vendors are expected to offer modes in which the near memory is used as cache, but we believe that this will be inefficient.« less

High-speed noise-free optical quantum memory

NASA Astrophysics Data System (ADS)

Kaczmarek, K. T.; Ledingham, P. M.; Brecht, B.; Thomas, S. E.; Thekkadath, G. S.; Lazo-Arjona, O.; Munns, J. H. D.; Poem, E.; Feizpour, A.; Saunders, D. J.; Nunn, J.; Walmsley, I. A.

2018-04-01

Optical quantum memories are devices that store and recall quantum light and are vital to the realization of future photonic quantum networks. To date, much effort has been put into improving storage times and efficiencies of such devices to enable long-distance communications. However, less attention has been devoted to building quantum memories which add zero noise to the output. Even small additional noise can render the memory classical by destroying the fragile quantum signatures of the stored light. Therefore, noise performance is a critical parameter for all quantum memories. Here we introduce an intrinsically noise-free quantum memory protocol based on two-photon off-resonant cascaded absorption (ORCA). We demonstrate successful storage of GHz-bandwidth heralded single photons in a warm atomic vapor with no added noise, confirmed by the unaltered photon-number statistics upon recall. Our ORCA memory meets the stringent noise requirements for quantum memories while combining high-speed and room-temperature operation with technical simplicity, and therefore is immediately applicable to low-latency quantum networks.

Affective picture processing: An integrative review of ERP findings

PubMed Central

Olofsson, Jonas K.; Nordin, Steven; Sequeira, Henrique; Polich, John

2008-01-01

The review summarizes and integrates findings from 40 years of event-related potential (ERP) studies using pictures that differ in valence (unpleasant-to-pleasant) and arousal (low-to-high) and that are used to elicit emotional processing. Affective stimulus factors primarily modulate ERP component amplitude, with little change in peak latency observed. Arousal effects are consistently obtained, and generally occur at longer latencies. Valence effects are inconsistently reported at several latency ranges, including very early components. Some affective ERP modulations vary with recording methodology, stimulus factors, as well as task-relevance and emotional state. Affective ERPs have been linked theoretically to attention orientation for unpleasant pictures at earlier components (< 300 ms). Enhanced stimulus processing has been associated with memory encoding for arousing pictures of assumed intrinsic motivational relevance, with task-induced differences contributing to emotional reactivity at later components (> 300 ms). Theoretical issues, stimulus factors, task demands, and individual differences are discussed. PMID:18164800

Adult onset-hypothyroidism increases response latency and long-term potentiation (LTP) in rat hippocampus

EPA Science Inventory

Thyroid hormones (TH) influence central nervous system (CNS) function during both development and in adulthood. The hippocampus is critical for some types of learning and memory and is particularly sensitive to thyroid hormone deficiency. Hypothyroidism in adulthood has been ass...

Factors influencing the response latencies of subnormal children in naming pictures.

PubMed

Elliott, C

1978-08-01

The times taken to name 56 drawings of objects on five separate occasions were analysed for 21 ESN(M) and 21 ESN(S) children, matched for picture-naming vocabulary. The ESN(S) group not only had a higher mean response latency but also showed greater inter- and intra-subject variance. Nine objects were selected whose names have a Thorndike-Lorge language frequency of 50 words per million or greater, and nine others were selected with a frequency of less than 50 words per million. Each object was drawn in two ways, one giving a two-dimensional outline with the addition of important detail, the other drawing also incorporating cues indicating the depth of the object. An analysis of variance of the children's latencies in naming the selected 36 pictures of 18 objects over five trials indicated that the method of drawing had no effect upon naming latencies. Pictures with high-frequency names were named faster than those with lower frequency names, the ESN(S) group showing a greater rate of increase in naming latency for the lower frequency words than the ESN(M) children. Results were discussed in terms of the Oldfield and Lachman models of lexical memory storage and of the search processes required for the retrieval of names.

Effect of ethanolic extract of Carpolobia lutea G. Don (polygalaceae) root on learning and memory in CD1 mice.

PubMed

Ajiwhen, I O; Bisong, S A

2013-12-20

Carpolobia lutea, commonly called cattle stick or poor man's candle, is used by traditional herbalists in eastern Nigeria to treat 'madness'. It has a reported analgesic and anti-nociceptive effect. The effect of its ethanolic root extract on learning and memory was investigated. Thirty mice were divided into three groups of ten each. One group of mice served as the control and was given normal saline (p.o.) while the other two groups were given acute low dose (1500mg/kg, p.o.) and high dose (2500mg/kg, p.o.) (LD50 3338.83mg/kg). The effect of the extract on cognitive memory was investigated using the Novel Object recognition task (NORT) while the effect on visuospatial learning and memory was studied using the Morris Water maze (MWM). The results obtained in the NORT show that the index of habituation was significantly lower following acute treatment with a low dose of C. lutea extract compared to control. However, the index of habituation did not differ following treatment with a high dose of C. lutea compared to control but it was higher compared to the low dose. Following treatment with a low dose of the extract, the index of discrimination was significantly higher compared to control. The index of discrimination in the high dose treatment group did not differ from control, but it was lower compared to the low dose treatment. This indicated that there was improved cognitive memory only in the low dose treatment group. In the MWM there was no significant difference in swim latency during Acquisition and Reversal training. There also was no significant difference in quadrant duration during probe trial. The swim latency during the visible platform test showed that all mice used had good visual acuity. Therefore, the ethanolic extract of C. lutea root enhanced cognitive memory. However it did not affect visuospatial learning and memory.

Zinc Chloride and Lead Acetate-Induced Passive Avoidance Memory Retention Deficits Reversed by Nicotine and Bucladesine in Mice.

PubMed

Tabrizian, Kaveh; Yazdani, Abdolmajid; Baheri, Behnam; Payandemehr, Borna; Sanati, Mehdi; Hashemzaei, Mahmoud; Miri, Abdolhossein; Zandkarimi, Majid; Belaran, Maryam; Fanoudi, Sahar; Sharifzadeh, Mohammad

2016-01-01

It is very important to investigate the neurotoxic effects of metals on learning and memory processes. In this study, we tried to investigate the effects and time course properties of oral administration of zinc chloride (25, 50, and 75 mg/kg, for 2 weeks), lead acetate (250, 750, 1,500, and 2,500 ppm for 4, 6 and 8 weeks), and their possible mechanisms on a model of memory function. For this matter, we examined the intra-peritoneal injections of nicotine (0.25, 0.5, 1, and 1.5 mg/kg) and bucladesine (50, 100, 300, and 600 nM/mouse) for 4 days alone and in combination with mentioned metals in the step-through passive avoidance task. Control animals received saline, drinking water, saline, and DMSO (dimethyl sulfoxide)/deionized water (1:9), respectively. At the end of each part of studies, animals were trained for 1 day in step-through task. The avoidance memory retention alterations were evaluated 24 and 48 h later in singular and combinational studies. Zinc chloride (75 mg/kg) oral gavage for 2 weeks decreased latency times compared to control animals. Also, lead acetate (750 ppm oral administrations for 8 weeks) caused significant lead blood levels and induced avoidance memory retention impairments. Four-days intra-peritoneal injection of nicotine (1 mg/kg) increased latency time compared to control animals. Finally, findings of this research showed that treatment with intra-peritoneal injections of nicotine (1 mg/kg) and/or bucladesine (600 nM/mouse) reversed zinc chloride- and lead acetate-induced avoidance memory retention impairments. Taken together, these results showed the probable role of cholinergic system and protein kinase A pathways in zinc chloride- and lead acetate-induced avoidance memory alterations.

Differentiation of perceptual and semantic subsequent memory effects using an orthographic paradigm.

PubMed

Kuo, Michael C C; Liu, Karen P Y; Ting, Kin Hung; Chan, Chetwyn C H

2012-11-27

This study aimed to differentiate perceptual and semantic encoding processes using subsequent memory effects (SMEs) elicited by the recognition of orthographs of single Chinese characters. Participants studied a series of Chinese characters perceptually (by inspecting orthographic components) or semantically (by determining the object making sounds), and then made studied or unstudied judgments during the recognition phase. Recognition performance in terms of d-prime measure in the semantic condition was higher, though not significant, than that of the perceptual condition. The between perceptual-semantic condition differences in SMEs at P550 and late positive component latencies (700-1000ms) were not significant in the frontal area. An additional analysis identified larger SME in the semantic condition during 600-1000ms in the frontal pole regions. These results indicate that coordination and incorporation of orthographic information into mental representation is essential to both task conditions. The differentiation was also revealed in earlier SMEs (perceptual>semantic) at N3 (240-360ms) latency, which is a novel finding. The left-distributed N3 was interpreted as more efficient processing of meaning with semantically learned characters. Frontal pole SMEs indicated strategic processing by executive functions, which would further enhance memory. Copyright © 2012 Elsevier B.V. All rights reserved.

Neurocognitive effects of multivitamin supplementation on the steady state visually evoked potential (SSVEP) measure of brain activity in elderly women.

PubMed

Macpherson, Helen; Silberstein, Richard; Pipingas, Andrew

2012-10-10

Growing evidence suggests that dietary supplementation with selected micronutrients and nutraceuticals may have the potential to improve cognition in older adults. Fewer studies have investigated the effects of these substances on brain activity. This study was a randomised, double-blind, placebo-controlled trial, conducted to explore the effects of 16 weeks supplementation with a combined multivitamin, mineral and herbal formula on the steady state visually evoked potential (SSVEP) measure of brain electrical activity. Participants were elderly women aged between 64 and 79 years, with subjective memory complaints. Baseline and post-treatment SSVEP data was obtained for 22 participants in the multivitamin group and 19 in the placebo group. A spatial working memory delayed response task (DRT) was performed during the recording of the SSVEP. The results revealed that when compared to placebo, multivitamin supplementation delayed SSVEP latency during retrieval, interpreted as an increase in inhibitory neural processes. Behavioural performance on the DRT was not improved by the multivitamin, however improved performance accuracy was associated with increased midline central SSVEP latency. There were no multivitamin-related effects on SSVEP amplitude. These findings indicate that in the elderly, multivitamin supplementation may enhance neural efficiency during memory retrieval. Copyright © 2012 Elsevier Inc. All rights reserved.

Requirement of NF-kappa B Activation in Different Mice Brain Areas during Long-Term Memory Consolidation in Two Contextual One-Trial Tasks with Opposing Valences

PubMed Central

Salles, Angeles; Krawczyk, Maria del C.; Blake, Mariano; Romano, Arturo; Boccia, Mariano M.; Freudenthal, Ramiro

2017-01-01

NF-kappa B is a transcription factor whose activation has been shown to be necessary for long-term memory consolidation in several species. NF-kappa B is activated and translocates to the nucleus of cells in a specific temporal window during consolidation. Our work focuses on a one trial learning tasks associated to the inhibitory avoidance (IA) setting. Mice were trained either receiving or not a footshock when entering a dark compartment (aversive vs. appetitive learning). Regardless of training condition (appetitive or aversive), latencies to step-through during testing were significantly different to those measured during training. Additionally, these testing latencies were also different from those of a control group that only received a shock unrelated to context. Moreover, nuclear NF-kappa B DNA-binding activity was augmented in the aversive and the appetitive tasks when compared with control and naïve animals. NF-kappa B inhibition by Sulfasalazine injected either in the Hippocampus, Amygdala or Nucleus accumbens immediately after training was able to impair retention in both training versions. Our results suggest that NF-kappa B is a critical molecular step, in different brain areas on memory consolidation. This was the case for both the IA task and also the modified version of the same task where the footshock was omitted during training. This work aims to further investigate how appetitive and aversive memories are consolidated. PMID:28439227

Fault tolerant onboard packet switch architecture for communication satellites: Shared memory per beam approach

NASA Technical Reports Server (NTRS)

Shalkhauser, Mary JO; Quintana, Jorge A.; Soni, Nitin J.

1994-01-01

The NASA Lewis Research Center is developing a multichannel communication signal processing satellite (MCSPS) system which will provide low data rate, direct to user, commercial communications services. The focus of current space segment developments is a flexible, high-throughput, fault tolerant onboard information switching processor. This information switching processor (ISP) is a destination-directed packet switch which performs both space and time switching to route user information among numerous user ground terminals. Through both industry study contracts and in-house investigations, several packet switching architectures were examined. A contention-free approach, the shared memory per beam architecture, was selected for implementation. The shared memory per beam architecture, fault tolerance insertion, implementation, and demonstration plans are described.

Redundant single event upset supression system

DOEpatents

Hoff, James R.

2006-04-04

CMOS transistors are configured to operate as either a redundant, SEU-tolerant, positive-logic, cross-coupled Nor Gate SR-flip flop or a redundant, SEU-tolerant, negative-logic, cross-coupled Nand Gate SR-flip flop. The register can operate as a memory, and further as a memory that can overcome the effects of radiation. As an SR-flip flop, the invention can be altered into any known type of latch or flip-flop by the application of external logic, thereby extending radiation tolerance to devices previously incapable of radiation tolerance. Numerous registers can be logically connected and replicated thereby being electronically configured to operate as a redundant circuit.

Reorganization in Semantic Memory: An Interpretation of the Facilitation Effect

ERIC Educational Resources Information Center

Hopf-Weichel, Rosemarie

1977-01-01

A model is proposed in which information processing is accompanied by dynamic processes, including the reorganization of items into active patterns and their subsequent displacement. Research using category names and instances showed that reaction times decreased with each successive repetition under one condition, but longer latencies were…

Molecular control of HIV-1 postintegration latency: implications for the development of new therapeutic strategies

PubMed Central

2009-01-01

The persistence of HIV-1 latent reservoirs represents a major barrier to virus eradication in infected patients under HAART since interruption of the treatment inevitably leads to a rebound of plasma viremia. Latency establishes early after infection notably (but not only) in resting memory CD4+ T cells and involves numerous host and viral trans-acting proteins, as well as processes such as transcriptional interference, RNA silencing, epigenetic modifications and chromatin organization. In order to eliminate latent reservoirs, new strategies are envisaged and consist of reactivating HIV-1 transcription in latently-infected cells, while maintaining HAART in order to prevent de novo infection. The difficulty lies in the fact that a single residual latently-infected cell can in theory rekindle the infection. Here, we review our current understanding of the molecular mechanisms involved in the establishment and maintenance of HIV-1 latency and in the transcriptional reactivation from latency. We highlight the potential of new therapeutic strategies based on this understanding of latency. Combinations of various compounds used simultaneously allow for the targeting of transcriptional repression at multiple levels and can facilitate the escape from latency and the clearance of viral reservoirs. We describe the current advantages and limitations of immune T-cell activators, inducers of the NF-κB signaling pathway, and inhibitors of deacetylases and histone- and DNA- methyltransferases, used alone or in combinations. While a solution will not be achieved by tomorrow, the battle against HIV-1 latent reservoirs is well- underway. PMID:19961595

Interval dosing with the HDAC inhibitor vorinostat effectively reverses HIV latency

PubMed Central

Archin, Nancie M.; Kirchherr, Jennifer L.; Sung, Julia A.M.; Clutton, Genevieve; Sholtis, Katherine; Xu, Yinyan; Allard, Brigitte; Stuelke, Erin; Kashuba, Angela D.; Kuruc, Joann D.; Gay, Cynthia L.; Goonetilleke, Nilu

2017-01-01

BACKGROUND. The histone deacetylase (HDAC) inhibitor vorinostat (VOR) can increase HIV RNA expression in vivo within resting CD4+ T cells of aviremic HIV+ individuals. However, while studies of VOR or other HDAC inhibitors have reported reversal of latency, none has demonstrated clearance of latent infection. We sought to identify the optimal dosing of VOR for effective serial reversal of HIV latency. METHODS. In a study of 16 HIV-infected, aviremic individuals, we measured resting CD4+ T cell–associated HIV RNA ex vivo and in vivo following a single exposure to VOR, and then in vivo after a pair of doses separated by 48 or 72 hours, and finally following a series of 10 doses given at 72-hour intervals. RESULTS. Serial VOR exposures separated by 72 hours most often resulted in an increase in cell-associated HIV RNA within circulating resting CD4+ T cells. VOR was well tolerated by all participants. However, despite serial reversal of latency over 1 month of VOR dosing, we did not observe a measurable decrease (>0.3 log10) in the frequency of latent infection within resting CD4+ T cells. CONCLUSIONS. These findings outline parameters for the experimental use of VOR to clear latent infection. Latency reversal can be achieved by VOR safely and repeatedly, but effective depletion of persistent HIV infection will require additional advances. In addition to improvements in latency reversal, these advances may include the sustained induction of potent antiviral immune responses capable of recognizing and clearing the rare cells in which HIV latency has been reversed. TRIAL REGISTRATION. Clinicaltrials.gov NCT01319383. FUNDING. NIH grants U01 AI095052, AI50410, and P30 CA016086 and National Center for Advancing Translational Sciences grant KL2 TR001109. PMID:28714868

How memory mechanisms are a key component in the guidance of our eye movements: evidence from the global effect.

PubMed

Silvis, J D; Van der Stigchel, S

2014-04-01

Investigating eye movements has been a promising approach to uncover the role of visual working memory in early attentional processes. Prior research has already demonstrated that eye movements in search tasks are more easily drawn toward stimuli that show similarities to working memory content, as compared with neutral stimuli. Previous saccade tasks, however, have always required a selection process, thereby automatically recruiting working memory. The present study was an attempt to confirm the role of working memory in oculomotor selection in an unbiased saccade task that rendered memory mechanisms irrelevant. Participants executed a saccade in a display with two elements, without any instruction to aim for one particular element. The results show that when two objects appear simultaneously, a working memory match attracts the first saccade more profoundly than do mismatch objects, an effect that was present throughout the saccade latency distribution. These findings demonstrate that memory plays a fundamental biasing role in the earliest competitive processes in the selection of visual objects, even when working memory is not recruited during selection.

Protection against brain tissues oxidative damage as a possible mechanism for the beneficial effects of Rosa damascena hydroalcoholic extract on scopolamine induced memory impairment in rats.

PubMed

Mohammadpour, Toktam; Hosseini, Mahmoud; Naderi, Asieh; Karami, Reza; Sadeghnia, Hamid Reza; Soukhtanloo, Mohammad; Vafaee, Farzaneh

2015-10-01

Hypnotic, analgesic, anticonvulsant, and antioxidant effects of Rosa damascena have been reported. This study, investigated the effect of R. damascena hydroalcoholic extract on memory performance in a scopolamine-induced memory impairment model. The rats were divided into control group received just saline; scopolamine group was treated by saline for 2 weeks, but was injected by scopolamine 30 minutes before each trial in Morris water maze test; treatment groups (scopolamine + extract 50; Sco + Ext 50) and (scopolamine + extract 250; Sco + Ext 250) were daily treated by 50 and 250 mg/kg of R. damascena extract (2 weeks) and were finally injected by scopolamine before each trial in Morris water maze. The brains were removed for biochemical measurements. Time latency and path length in the scopolamine group were higher than control (P < 0.01 to <0.001). Both treatment groups showed shorter traveled distance and time latency compared with scopolamine group (P < 0.05 to <0.001). Time spent in target quadrant by scopolamine group was lower than control (P < 0.05), while Sco + Ext 250 group spent longer time in target quadrant than scopolamine group (P < 0.05). Malondialdehyde concentrations in hippocampal and cortical tissues of scopolamine group were higher, while thiol concentrations were lower than control ones (P < 0.001). Treatment by both doses of the extract decreased the malondialdehyde concentration, while increased the thiol concentration (P < 0.05 to <0.001). The results of this study showed that the hydroalcoholic extract of R. damascena prevents scopolamine-induced memory deficits. This finding suggests that memory improvement may be in part due to the antioxidant effects.

Hippocampal Aromatization Modulates Spatial Memory and Characteristics of the Synaptic Membrane in the Male Zebra Finch

PubMed Central

Makeyeva, Yekaterina V.; Paitel, Elizabeth R.; Pedersen, Alyssa L.; Hon, Angel T.; Gunderson, Jordan A.; Saldanha, Colin J.

2017-01-01

The estrogen-synthesizing enzyme aromatase is abundant at the synapse in the zebra finch hippocampus (HP), and its inhibition impairs spatial memory function. To more fully test the role of local estradiol (E2) synthesis in memory, the HP of adult male zebra finches was exposed to either control pellets or those containing the aromatase inhibitor 1,4,6-androstatriene-3,17-dione (ATD), ATD and E2, ATD and the G protein-coupled estrogen receptor (GPER) agonist G1, or the antagonist G15 alone. Birds were tested for spatial memory acquisition and performance, and HP levels of the postsynaptic protein PSD95 were measured. ATD-treated birds took longer to reach criterion than control birds, whereas acquisition in ATD+E2 and ATD+G1 birds was indistinguishable from control and ATD treatments. Interestingly, all G15 birds failed to acquire the task. Following a retention interval, ATD birds took the longest to reach the (formerly) baited cup and made the most mistakes. ATD+E2 animals displayed the lowest retention latencies and made fewer mistakes than ATD-treated birds, and ATD+G1 birds did not significantly differ from controls in retention latencies. The amount of PSD95 in the HP was lowest in ATD-treated animals compared with birds with silicone-only–implanted craniotomies, ATD+E2, and ATD+G1 birds, who did not differ in this expression. Thus, spatial memory acquisition and performance appear aromatase and E2 dependent, an effect more reliably revealed after consolidation and/or recall compared to acquisition. E2 may exert this effect via GPERs, resulting in an increase in PSD95 levels that may modify receptor activity or intracellular signaling pathways to increase synaptic strength. PMID:28324066

Crocin improved amyloid beta induced long-term potentiation and memory deficits in the hippocampal CA1 neurons in freely moving rats.

PubMed

Hadipour, Mohammadmehdi; Kaka, Gholamreza; Bahrami, Farideh; Meftahi, Gholam Hossein; Pirzad Jahromi, Gila; Mohammadi, Alireza; Sahraei, Hedayat

2018-05-01

Extracellular beta-amyloid (Aβ) accumulation and deposition is the main factor, which causes synaptic loss and eventually cells death in Alzheimer's disease (AD). Memory loss and long-term potentiation (LTP) dysfunction in the hippocampus are involved in the AD. The involvement of crocin, as the main and active constituent of saffron extract in learning and memory processes, has been proposed. Here we investigated the probable therapeutic effect of crocin on memory, LTP, and neuronal apoptosis using in vivo Aβ models of the AD. The Aβ peptide (1-42) was bilaterally administered into the frontal-cortex using stereotaxic apparatus. Five hours after surgery, rats were given intraperitoneal crocin (30 mg/kg) daily, which repeated for 12 days. Barnes maze results showed that administration of crocin significantly improves spatial memory indicators such as latency time to achieving the target hole and the number of errors when compared to Aβ-group. Passive avoidance test revealed that crocin significantly increased the step-through-latency compared to Aβ-treated alone. These learning deficits in Aβ-treated animals correlated with a reduction of LTP in hippocampal CA1 synapses in freely moving rats, which crocin improved population spike amplitude and mean field excitatory postsynaptic potentials (fEPSP) slope reduction induced by Aβ. Neuronal apoptosis was detected by TUNEL assay and the expression levels of c-Fos proteins were examined by Western blotting. Crocin significantly reduced the number of TUNEL-positive cells in the CA1 region and decreased c-Fos in the hippocampus compared to Aβ-group. In vivo Aβ treatment altered significantly the electrophysiological properties of CA1 neurons and crocin further confirmed a neuroprotective action against Aβ toxicity. © 2018 Wiley Periodicals, Inc.

Changes in oxidative metabolism and memory and learning in an cerebral hypoperfusion model in rats.

PubMed

Castaño Guerrero, Y; González Fraguela, M E; Fernández Verdecia, I; Horruitiner Gutiérrez, I; Piedras Carpio, S

2013-01-01

Chronic hypoperfusion in rats produces memory and learning impairments due to permanent occlusion of commun carotid arteries (POCCA). Molecular mechanisms leading to behavioural disorders have been poorly studied. For this reason, the aim of the present study was to characterise oxidative metabolism disorders and their implications in memory and learning impairments. Superoxide dismutase (SOD) and catalase (CAT) activities were determined in cortex, hippocampus and striatum homogenates at 24 hours and at 22 days after the lesion. Haematoxylin-eosin staining and glial fibrillary acidic protein (GFAP) immunoreactivity were performed on coronal sections. Behavioural impairments were explored using the Morris water maze (MWM). Escape latencies were determined in all behavioural studies. The lesion induced a significant increase (P<.01) in CAT activity in the cortex at 24 hours, while SOD activity was significantly higher (P<.01) in the cortex and hippocampus at 22 days. An intense vacuolization was observed in the cortex and striatum as a result of the lesion. A neuronal loss in the striatum and hippocampus was observed. The glial reaction increased in the cortex and striatum. Visual alterations were observed in the lesion group with the lowest evolution time (P<.001). Escape latencies, corresponding to MWM schemes for long-term and short-term memory evaluation increased significantly (P<.05) in both groups of lesioned animals. It was concluded that changes in SOD and CAT activities indicate a possible implication of oxidative imbalance in the pathology associated with chronic cerebral hypoperfusion. In addition, the POCCA model in rats is useful for understanding mechanisms by which cerebral hypoperfusion produces memory and learning impairments. Copyright © 2011 Sociedad Española de Neurología. Published by Elsevier Espana. All rights reserved.

Memory deficits associated with khat (Catha edulis) use in rodents.

PubMed

Kimani, S T; Patel, N B; Kioy, P G

2016-02-01

Khat products and chewing practices are common in East Africa, Middle East for centuries with concomitant socio-economic and public health repercussions. We assessed memory deficits associated with khat use in rodents. Young male CBA mice, 5-7 weeks old (n = 20), weighing 25-35 g were used. Mice were treated with either 40, 120 or 360 mg/kg body weight (bw) methanolic khat extract, or 0.5 ml saline for 10 days. Spatial acquisition, reversal and reference memory were assessed using modified Morris Water maze (MMWM). Mice treated with 40 mg/kg khat extract had longer (t4 = 4.12 p = 0.015) and t4 = 2.28 p = 0.065) escape latency on first and second day during reversal relative to the baseline. Under 120 mg/kg khat dose, the escape latency was shorter (t4 = -2.49 p = 0.05) vs (t3 = -2.5 p = 0.05) on third and fourth day. Further, treatment with 360 mg/kg khat extract resulted in significantly longer time (49.13, 33.5, 40.2 and 35.75) vs. (23.5 s), compared to baseline. Mice treated with khat or control preferred the target quadrant post acquisition while differential pattern was seen during reversal phase. Mice treated with 40 or 120 mg/kg khat showed significant preference for target quadrant. Substantial time (19.9) was spent in the old target compared to the new (16.9 s) by animals treated with highest dose however, the difference was not significant. There is a biological plausibility that chronic khat use may induce memory deficits and impair cognitive flexibility. The differential patterns of memory deficits may reflect the differences in dose effect as well as time dependent impairment.

Hippocampal Aromatization Modulates Spatial Memory and Characteristics of the Synaptic Membrane in the Male Zebra Finch.

PubMed

Bailey, David J; Makeyeva, Yekaterina V; Paitel, Elizabeth R; Pedersen, Alyssa L; Hon, Angel T; Gunderson, Jordan A; Saldanha, Colin J

2017-04-01

The estrogen-synthesizing enzyme aromatase is abundant at the synapse in the zebra finch hippocampus (HP), and its inhibition impairs spatial memory function. To more fully test the role of local estradiol (E2) synthesis in memory, the HP of adult male zebra finches was exposed to either control pellets or those containing the aromatase inhibitor 1,4,6-androstatriene-3,17-dione (ATD), ATD and E2, ATD and the G protein-coupled estrogen receptor (GPER) agonist G1, or the antagonist G15 alone. Birds were tested for spatial memory acquisition and performance, and HP levels of the postsynaptic protein PSD95 were measured. ATD-treated birds took longer to reach criterion than control birds, whereas acquisition in ATD+E2 and ATD+G1 birds was indistinguishable from control and ATD treatments. Interestingly, all G15 birds failed to acquire the task. Following a retention interval, ATD birds took the longest to reach the (formerly) baited cup and made the most mistakes. ATD+E2 animals displayed the lowest retention latencies and made fewer mistakes than ATD-treated birds, and ATD+G1 birds did not significantly differ from controls in retention latencies. The amount of PSD95 in the HP was lowest in ATD-treated animals compared with birds with silicone-only-implanted craniotomies, ATD+E2, and ATD+G1 birds, who did not differ in this expression. Thus, spatial memory acquisition and performance appear aromatase and E2 dependent, an effect more reliably revealed after consolidation and/or recall compared to acquisition. E2 may exert this effect via GPERs, resulting in an increase in PSD95 levels that may modify receptor activity or intracellular signaling pathways to increase synaptic strength. Copyright © 2017 Endocrine Society.

Two-level main memory co-design: Multi-threaded algorithmic primitives, analysis, and simulation

DOE PAGES

Bender, Michael A.; Berry, Jonathan W.; Hammond, Simon D.; ...

2017-01-03

A challenge in computer architecture is that processors often cannot be fed data from DRAM as fast as CPUs can consume it. Therefore, many applications are memory-bandwidth bound. With this motivation and the realization that traditional architectures (with all DRAM reachable only via bus) are insufficient to feed groups of modern processing units, vendors have introduced a variety of non-DDR 3D memory technologies (Hybrid Memory Cube (HMC),Wide I/O 2, High Bandwidth Memory (HBM)). These offer higher bandwidth and lower power by stacking DRAM chips on the processor or nearby on a silicon interposer. We will call these solutions “near-memory,” andmore » if user-addressable, “scratchpad.” High-performance systems on the market now offer two levels of main memory: near-memory on package and traditional DRAM further away. In the near term we expect the latencies near-memory and DRAM to be similar. Here, it is natural to think of near-memory as another module on the DRAM level of the memory hierarchy. Vendors are expected to offer modes in which the near memory is used as cache, but we believe that this will be inefficient.« less

Memory Retrieval Has a Dynamic Influence on the Maintenance Mechanisms That Are Sensitive to ζ-Inhibitory Peptide (ZIP).

PubMed

Levitan, David; Fortis-Santiago, Yaihara; Figueroa, Joshua A; Reid, Emily E; Yoshida, Takashi; Barry, Nicholas C; Russo, Abigail; Katz, Donald B

2016-10-12

In neuroscientists' attempts to understand the long-term storage of memory, topics of particular importance and interest are the cellular and system mechanisms of maintenance (e.g., those sensitive to ζ-inhibitory peptide, ZIP) and those induced by memory retrieval (i.e., reconsolidation). Much is known about each of these processes in isolation, but less is known concerning how they interact. It is known that ZIP sensitivity and memory retrieval share at least some molecular targets (e.g., recycling α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid, AMPA, receptors to the plasma membrane); conversely, the fact that sensitivity to ZIP emerges only after consolidation ends suggests that consolidation (and by extension reconsolidation) and maintenance might be mutually exclusive processes, the onset of one canceling the other. Here, we use conditioned taste aversion (CTA) in rats, a cortically dependent learning paradigm, to test this hypothesis. First, we demonstrate that ZIP infusions into gustatory cortex begin interfering with CTA memory 43-45 h after memory acquisition-after consolidation ends. Next, we show that a retrieval trial administered after this time point interrupts the ability of ZIP to induce amnesia and that ZIP's ability to induce amnesia is reengaged only 45 h after retrieval. This pattern of results suggests that memory retrieval and ZIP-sensitive maintenance mechanisms are mutually exclusive and that the progression from one to the other are similar after acquisition and retrieval. They also reveal concrete differences between ZIP-sensitive mechanisms induced by acquisition and retrieval: the latency with which ZIP-sensitive mechanisms are expressed differ for the two processes. Memory retrieval and the molecular mechanisms that are sensitive to ζ-inhibitory peptide (ZIP) are the few manipulations that have been shown to effect memory maintenance. Although much is known about their effect on maintenance separately, it is unknown how they interact. Here, we describe a model for the interaction between memory retrieval and ZIP-sensitive mechanisms, showing that retrieval trials briefly (i.e., for 45 h) interrupt these mechanisms. ZIP sensitivity emerges across a similar time window after memory acquisition and retrieval; the maintenance mechanisms that follow acquisition and retrieval differ, however, in the latency with which the impact of ZIP is expressed. Copyright © 2016 the authors 0270-6474/16/3610654-09$15.00/0.

Efficient and flexible memory architecture to alleviate data and context bandwidth bottlenecks of coarse-grained reconfigurable arrays

NASA Astrophysics Data System (ADS)

Yang, Chen; Liu, LeiBo; Yin, ShouYi; Wei, ShaoJun

2014-12-01

The computational capability of a coarse-grained reconfigurable array (CGRA) can be significantly restrained due to data and context memory bandwidth bottlenecks. Traditionally, two methods have been used to resolve this problem. One method loads the context into the CGRA at run time. This method occupies very small on-chip memory but induces very large latency, which leads to low computational efficiency. The other method adopts a multi-context structure. This method loads the context into the on-chip context memory at the boot phase. Broadcasting the pointer of a set of contexts changes the hardware configuration on a cycle-by-cycle basis. The size of the context memory induces a large area overhead in multi-context structures, which results in major restrictions on application complexity. This paper proposes a Predictable Context Cache (PCC) architecture to address the above context issues by buffering the context inside a CGRA. In this architecture, context is dynamically transferred into the CGRA. Utilizing a PCC significantly reduces the on-chip context memory and the complexity of the applications running on the CGRA is no longer restricted by the size of the on-chip context memory. Data preloading is the most frequently used approach to hide input data latency and speed up the data transmission process for the data bandwidth issue. Rather than fundamentally reducing the amount of input data, the transferred data and computations are processed in parallel. However, the data preloading method cannot work efficiently because data transmission becomes the critical path as the reconfigurable array scale increases. This paper also presents a Hierarchical Data Memory (HDM) architecture as a solution to the efficiency problem. In this architecture, high internal bandwidth is provided to buffer both reused input data and intermediate data. The HDM architecture relieves the external memory from the data transfer burden so that the performance is significantly improved. As a result of using PCC and HDM, experiments running mainstream video decoding programs achieved performance improvements of 13.57%-19.48% when there was a reasonable memory size. Therefore, 1080p@35.7fps for H.264 high profile video decoding can be achieved on PCC and HDM architecture when utilizing a 200 MHz working frequency. Further, the size of the on-chip context memory no longer restricted complex applications, which were efficiently executed on the PCC and HDM architecture.

REPEATED INHALATION OF TOLUENE BY RATS PERFORMING A SIGNAL DETECTION TASK LEADS TO BEHVIORAL TOLERANCE ON SOME PERFORMANCE MEASURES.

EPA Science Inventory

Previous work showed that trichloroethylene (TCE) impairs sustained attention as evidenced by a reduction in accuracy and elevation of response latencies in rats trained to perform a visual signal detection task (SDT). This work also showed that these effects abate during repeat...

AADL and Model-based Engineering

DTIC Science & Technology

2014-10-20

and MBE Feiler, Oct 20, 2014 © 2014 Carnegie Mellon University We Rely on Software for Safe Aircraft Operation Embedded software systems ...D eveloper Compute Platform Runtime Architecture Application Software Embedded SW System Engineer Data Stream Characteristics Latency...confusion Hardware Engineer Why do system level failures still occur despite fault tolerance techniques being deployed in systems ? Embedded software

Fault Tolerant Frequent Pattern Mining

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

Shohdy, Sameh; Vishnu, Abhinav; Agrawal, Gagan

FP-Growth algorithm is a Frequent Pattern Mining (FPM) algorithm that has been extensively used to study correlations and patterns in large scale datasets. While several researchers have designed distributed memory FP-Growth algorithms, it is pivotal to consider fault tolerant FP-Growth, which can address the increasing fault rates in large scale systems. In this work, we propose a novel parallel, algorithm-level fault-tolerant FP-Growth algorithm. We leverage algorithmic properties and MPI advanced features to guarantee an O(1) space complexity, achieved by using the dataset memory space itself for checkpointing. We also propose a recovery algorithm that can use in-memory and disk-based checkpointing,more » though in many cases the recovery can be completed without any disk access, and incurring no memory overhead for checkpointing. We evaluate our FT algorithm on a large scale InfiniBand cluster with several large datasets using up to 2K cores. Our evaluation demonstrates excellent efficiency for checkpointing and recovery in comparison to the disk-based approach. We have also observed 20x average speed-up in comparison to Spark, establishing that a well designed algorithm can easily outperform a solution based on a general fault-tolerant programming model.« less

On-chip phase-change photonic memory and computing

NASA Astrophysics Data System (ADS)

Cheng, Zengguang; Ríos, Carlos; Youngblood, Nathan; Wright, C. David; Pernice, Wolfram H. P.; Bhaskaran, Harish

2017-08-01

The use of photonics in computing is a hot topic of interest, driven by the need for ever-increasing speed along with reduced power consumption. In existing computing architectures, photonic data storage would dramatically improve the performance by reducing latencies associated with electrical memories. At the same time, the rise of `big data' and `deep learning' is driving the quest for non-von Neumann and brain-inspired computing paradigms. To succeed in both aspects, we have demonstrated non-volatile multi-level photonic memory avoiding the von Neumann bottleneck in the existing computing paradigm and a photonic synapse resembling the biological synapses for brain-inspired computing using phase-change materials (Ge2Sb2Te5).

A fault-tolerant information processing concept for space vehicles.

NASA Technical Reports Server (NTRS)

Hopkins, A. L., Jr.

1971-01-01

A distributed fault-tolerant information processing system is proposed, comprising a central multiprocessor, dedicated local processors, and multiplexed input-output buses connecting them together. The processors in the multiprocessor are duplicated for error detection, which is felt to be less expensive than using coded redundancy of comparable effectiveness. Error recovery is made possible by a triplicated scratchpad memory in each processor. The main multiprocessor memory uses replicated memory for error detection and correction. Local processors use any of three conventional redundancy techniques: voting, duplex pairs with backup, and duplex pairs in independent subsystems.

A Massively Parallel Code for Polarization Calculations

NASA Astrophysics Data System (ADS)

Akiyama, Shizuka; Höflich, Peter

2001-03-01

We present an implementation of our Monte-Carlo radiation transport method for rapidly expanding, NLTE atmospheres for massively parallel computers which utilizes both the distributed and shared memory models. This allows us to take full advantage of the fast communication and low latency inherent to nodes with multiple CPUs, and to stretch the limits of scalability with the number of nodes compared to a version which is based on the shared memory model. Test calculations on a local 20-node Beowulf cluster with dual CPUs showed an improved scalability by about 40%.

Cache-based error recovery for shared memory multiprocessor systems

NASA Technical Reports Server (NTRS)

Wu, Kun-Lung; Fuchs, W. Kent; Patel, Janak H.

1989-01-01

A multiprocessor cache-based checkpointing and recovery scheme for of recovering from transient processor errors in a shared-memory multiprocessor with private caches is presented. New implementation techniques that use checkpoint identifiers and recovery stacks to reduce performance degradation in processor utilization during normal execution are examined. This cache-based checkpointing technique prevents rollback propagation, provides for rapid recovery, and can be integrated into standard cache coherence protocols. An analytical model is used to estimate the relative performance of the scheme during normal execution. Extensions that take error latency into account are presented.

Simulation of the High Performance Time to Digital Converter for the ATLAS Muon Spectrometer trigger upgrade

NASA Astrophysics Data System (ADS)

Meng, X. T.; Levin, D. S.; Chapman, J. W.; Zhou, B.

2016-09-01

The ATLAS Muon Spectrometer endcap thin-Resistive Plate Chamber trigger project compliments the New Small Wheel endcap Phase-1 upgrade for higher luminosity LHC operation. These new trigger chambers, located in a high rate region of ATLAS, will improve overall trigger acceptance and reduce the fake muon trigger incidence. These chambers must generate a low level muon trigger to be delivered to a remote high level processor within a stringent latency requirement of 43 bunch crossings (1075 ns). To help meet this requirement the High Performance Time to Digital Converter (HPTDC), a multi-channel ASIC designed by CERN Microelectronics group, has been proposed for the digitization of the fast front end detector signals. This paper investigates the HPTDC performance in the context of the overall muon trigger latency, employing detailed behavioral Verilog simulations in which the latency in triggerless mode is measured for a range of configurations and under realistic hit rate conditions. The simulation results show that various HPTDC operational configurations, including leading edge and pair measurement modes can provide high efficiency (>98%) to capture and digitize hits within a time interval satisfying the Phase-1 latency tolerance.

Post-training reversible disconnection of the ventral hippocampal-basolateral amygdaloid circuits impairs consolidation of inhibitory avoidance memory in rats.

PubMed

Wang, Gong-Wu; Liu, Jian; Wang, Xiao-Qin

2017-11-01

The ventral hippocampus (VH) and the basolateral amygdala (BLA) are both crucial in inhibitory avoidance (IA) memory. However, the exact role of the VH-BLA circuit in IA memory consolidation is unclear. This study investigated the effect of post-training reversible disconnection of the VH-BLA circuit in IA memory consolidation. Male Wistar rats with implanted guide cannulae were trained with a one-trial IA task, then received immediate intracerebral injections of muscimol or saline, and were tested 24 h later. Muscimol injection into the bilateral BLA, or the unilateral VH and contralateral BLA, but not the unilateral VH and ipsilateral BLA, significantly decreased the retention latencies (versus saline treatment). The results suggest that the VH-BLA circuit could be an important circuit to modulate consolidation of IA memory in rats. © 2017 Wang et al.; Published by Cold Spring Harbor Laboratory Press.

Efficacy and tolerability of ramelteon in a double-blind, placebo-controlled, crossover study in Japanese patients with chronic primary insomnia.

PubMed

Kohsaka, Masako; Kanemura, Takashi; Taniguchi, Mitsutaka; Kuwahara, Hiroo; Mikami, Akira; Kamikawa, Kunihisa; Uno, Hideki; Ogawa, Atsushi; Murasaki, Mitsukuni; Sugita, Yoshiro

2011-10-01

The aim of this study was to evaluate the efficacy and safety of ramelteon 4, 8, 16 or 32 mg and placebo in Japanese patients with chronic insomnia using a randomized, double-blind, five-period crossover design. A total of 65 Japanese patients with chronic primary insomnia received ramelteon or placebo for two nights each in sleep laboratories. Changes in sleep parameters were assessed objectively by polysomnography and subjectively by postsleep questionnaires. Safety and tolerability was evaluated by assessment of the occurrence of adverse events, next-day residual effects and laboratory and ECG investigations. Ramelteon 8 and 32 mg significantly shortened the mean latency to persistent sleep in comparison with placebo, and there was a statistically significant trend for linear dose-response for this sleep parameter. Overall changes in sleep architecture were modest (<3% changes vs placebo), with increases in stage 1 and decreases in stage 3/4. Ramelteon was well tolerated, the most common adverse effect being somnolence, which was similar to placebo at doses up to 8 mg, but increased with higher doses. Next-day residual effects occurred no more frequently with ramelteon at any dose than with placebo. When compared with sleep latency data from a similarly-designed US study, there was no evidence of any ethnic differences in the efficacy of ramelteon between Japanese and US patients. Overall, ramelteon 8 mg showed the most favorable balance between sleep-promoting effects and tolerability. The unique efficacy profile of ramelteon, promoting sleep initiation without affecting other sleep parameters, may be due to its circadian shifting effect.

Ionizing radiation as preconditioning against transient cerebral ischemia in rats.

PubMed

Kokošová, Natália; Danielisová, Viera; Smajda, Beňadik; Burda, Jozef

2014-01-01

Induction of ischemic tolerance (IT), the ability of an organism to survive an otherwise lethal ischemia, is the most effective known approach to preventing postischemic damage. IT can be induced by exposing animals to a broad range of stimuli. In this study we tried to induce IT of brain neurons using ionizing radiation (IR). A preconditioning (pre-C) dose of 10, 20, 30 or 50 Gy of gamma rays was used 2 days before an 8 min ischemia in adult male rats. Ischemia alone caused the degeneration of almost one half of neurons in CA1 region of hippocampus. However, a significant decrease of the number of degenerating neurons was observed after higher doses of radiation (30 and 50 Gy). Moreover, ischemia significantly impaired the spatial memory of rats as tested in Morris's water maze. In rats with a 50 Gy pre-C dose, the latency times were reduced to values close to the control level. Our study is the first to reveal that IR applied in sufficient doses can induce IT and thus allow pyramidal CA1 neurons to survive ischemia. In addition, we show that the beneficial effect of IR pre-C is proportional to the radiation dose.

Digital Plasma Control System for Alcator C-Mod

NASA Astrophysics Data System (ADS)

Ferrara, M.; Wolfe, S.; Stillerman, J.; Fredian, T.; Hutchinson, I.

2004-11-01

A digital plasma control system (DPCS) has been designed to replace the present C-Mod system, which is based on hybrid analog-digital computer. The initial implementation of DPCS comprises two 64 channel, 16 bit, low-latency cPCI digitizers, each with 16 analog outputs, controlled by a rack-mounted single-processor Linux server, which also serves as the compute engine. A prototype system employing three older 32 channel digitizers was tested during the 2003-04 campaign. The hybrid's linear PID feedback system was emulated by IDL code executing a synchronous loop, using the same target waveforms and control parameters. Reliable real-time operation was accomplished under a standard Linux OS (RH9) by locking memory and disabling interrupts during the plasma pulse. The DPCS-computed outputs agreed to within a few percent with those produced by the hybrid system, except for discrepancies due to offsets and non-ideal behavior of the hybrid circuitry. The system operated reliably, with no sample loss, at more than twice the 10kHz design specification, providing extra time for implementing more advanced control algorithms. The code is fault-tolerant and produces consistent output waveforms even with 10% sample loss.

Scientific Application Requirements for Leadership Computing at the Exascale

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

Ahern, Sean; Alam, Sadaf R; Fahey, Mark R

2007-12-01

The Department of Energy s Leadership Computing Facility, located at Oak Ridge National Laboratory s National Center for Computational Sciences, recently polled scientific teams that had large allocations at the center in 2007, asking them to identify computational science requirements for future exascale systems (capable of an exaflop, or 1018 floating point operations per second). These requirements are necessarily speculative, since an exascale system will not be realized until the 2015 2020 timeframe, and are expressed where possible relative to a recent petascale requirements analysis of similar science applications [1]. Our initial findings, which beg further data collection, validation, andmore » analysis, did in fact align with many of our expectations and existing petascale requirements, yet they also contained some surprises, complete with new challenges and opportunities. First and foremost, the breadth and depth of science prospects and benefits on an exascale computing system are striking. Without a doubt, they justify a large investment, even with its inherent risks. The possibilities for return on investment (by any measure) are too large to let us ignore this opportunity. The software opportunities and challenges are enormous. In fact, as one notable computational scientist put it, the scale of questions being asked at the exascale is tremendous and the hardware has gotten way ahead of the software. We are in grave danger of failing because of a software crisis unless concerted investments and coordinating activities are undertaken to reduce and close this hardwaresoftware gap over the next decade. Key to success will be a rigorous requirement for natural mapping of algorithms to hardware in a way that complements (rather than competes with) compilers and runtime systems. The level of abstraction must be raised, and more attention must be paid to functionalities and capabilities that incorporate intent into data structures, are aware of memory hierarchy, possess fault tolerance, exploit asynchronism, and are power-consumption aware. On the other hand, we must also provide application scientists with the ability to develop software without having to become experts in the computer science components. Numerical algorithms are scattered broadly across science domains, with no one particular algorithm being ubiquitous and no one algorithm going unused. Structured grids and dense linear algebra continue to dominate, but other algorithm categories will become more common. A significant increase is projected for Monte Carlo algorithms, unstructured grids, sparse linear algebra, and particle methods, and a relative decrease foreseen in fast Fourier transforms. These projections reflect the expectation of much higher architecture concurrency and the resulting need for very high scalability. The new algorithm categories that application scientists expect to be increasingly important in the next decade include adaptive mesh refinement, implicit nonlinear systems, data assimilation, agent-based methods, parameter continuation, and optimization. The attributes of leadership computing systems expected to increase most in priority over the next decade are (in order of importance) interconnect bandwidth, memory bandwidth, mean time to interrupt, memory latency, and interconnect latency. The attributes expected to decrease most in relative priority are disk latency, archival storage capacity, disk bandwidth, wide area network bandwidth, and local storage capacity. These choices by application developers reflect the expected needs of applications or the expected reality of available hardware. One interpretation is that the increasing priorities reflect the desire to increase computational efficiency to take advantage of increasing peak flops [floating point operations per second], while the decreasing priorities reflect the expectation that computational efficiency will not increase. Per-core requirements appear to be relatively static, while aggregate requirements will grow with the system. This projection is consistent with a relatively small increase in performance per core with a dramatic increase in the number of cores. Leadership system software must face and overcome issues that will undoubtedly be exacerbated at the exascale. The operating system (OS) must be as unobtrusive as possible and possess more stability, reliability, and fault tolerance during application execution. As applications will be more likely at the exascale to experience loss of resources during an execution, the OS must mitigate such a loss with a range of responses. New fault tolerance paradigms must be developed and integrated into applications. Just as application input and output must not be an afterthought in hardware design, job management, too, must not be an afterthought in system software design. Efficient scheduling of those resources will be a major obstacle faced by leadership computing centers at the exas...« less

Virus-Specific Immune Memory at Peripheral Sites of Herpes Simplex Virus Type 2 (HSV-2) Infection in Guinea Pigs

PubMed Central

Xia, Jingya; Veselenak, Ronald L.; Gorder, Summer R.; Bourne, Nigel; Milligan, Gregg N.

2014-01-01

Despite its importance in modulating HSV-2 pathogenesis, the nature of tissue-resident immune memory to HSV-2 is not completely understood. We used genital HSV-2 infection of guinea pigs to assess the type and location of HSV-specific memory cells at peripheral sites of HSV-2 infection. HSV-specific antibody-secreting cells were readily detected in the spleen, bone marrow, vagina/cervix, lumbosacral sensory ganglia, and spinal cord of previously-infected animals. Memory B cells were detected primarily in the spleen and to a lesser extent in bone marrow but not in the genital tract or neural tissues suggesting that the HSV-specific antibody-secreting cells present at peripheral sites of HSV-2 infection represented persisting populations of plasma cells. The antibody produced by these cells isolated from neural tissues of infected animals was functionally relevant and included antibodies specific for HSV-2 glycoproteins and HSV-2 neutralizing antibodies. A vigorous IFN-γ-secreting T cell response developed in the spleen as well as the sites of HSV-2 infection in the genital tract, lumbosacral ganglia and spinal cord following acute HSV-2 infection. Additionally, populations of HSV-specific tissue-resident memory T cells were maintained at these sites and were readily detected up to 150 days post HSV-2 infection. Unlike the persisting plasma cells, HSV-specific memory T cells were also detected in uterine tissue and cervicothoracic region of the spinal cord and at low levels in the cervicothoracic ganglia. Both HSV-specific CD4+ and CD8+ resident memory cell subsets were maintained long-term in the genital tract and sensory ganglia/spinal cord following HSV-2 infection. Together these data demonstrate the long-term maintenance of both humoral and cellular arms of the adaptive immune response at the sites of HSV-2 latency and virus shedding and highlight the utility of the guinea pig infection model to investigate tissue-resident memory in the setting of HSV-2 latency and spontaneous reactivation. PMID:25485971

Specialised use of working memory by Portia africana, a spider-eating salticid.

PubMed

Cross, Fiona R; Jackson, Robert R

2014-03-01

Using expectancy-violation methods, we investigated the role of working memory in the predatory strategy of Portia africana, a salticid spider from Kenya that preys by preference on other spiders. One of this predator's tactics is to launch opportunistic leaping attacks on to other spiders in their webs. Focussing on this particular tactic, our experiments began with a test spider on a ramp facing a lure (dead prey spider mounted on a cork disc) that could be reached by leaping. After the test spider faced the lure for 30 s, we blocked the test spider's view of the lure by lowering an opaque shutter before the spider leapt. When the shutter was raised 90 s later, either the same lure came into view again (control) or a different lure came into view (experimental: different prey type in same orientation or same prey type in different orientation). We recorded attack frequency (number of test spiders that leapt at the lure) and attack latency (time elapsing between shutter being raised and spiders initiating a leap). Attack latencies in control trials were not significantly different from attack latencies in experimental trials, regardless of whether it was prey type or prey orientation that changed in the experimental trials. However, compared with test spiders in the no-change control trials, significantly fewer test spiders leapt when prey type changed. There was no significant effect on attack frequency when prey orientation changed. These findings suggest that this predator represents prey type independently of prey orientation.

Cognitive enhancing effect of angiotensin-converting enzyme inhibitors and angiotensin receptor blockers on learning and memory

PubMed Central

Nade, V. S.; Kawale, L. A.; Valte, K. D.; Shendye, N. V.

2015-01-01

Objective: The present study was designed to investigate cognitive enhancing property of angiotensin-converting enzymes inhibitors (ACEI) and angiotensin receptor blockers (ARBs) in rats. Materials and Methods: The elevated plus maze (EPM), passive avoidance test (PAT), and water maze test (WMT) were used to assess cognitive enhancing activity in young and aged rats. Ramipril (10 mg/kg, p.o.), perindopril (10 mg/kg, i.p), losartan (20 mg/kg, i.p), and valsartan (20 mg/kg, p.o) were administered to assess their effect on learning and memory. Scopolamine (1 mg/kg, i.p) was used to impair cognitive function. Piracetam (200 mg/kg, i.p) was used as reference drug. Results: All the treatments significantly attenuated amnesia induced by aging and scopolamine. In EPM, aged and scopolamine-treated rats showed an increase in transfer latency (TL) whereas, ACEI and ARBs showed a significant decrease in TL. Treatment with ACEI and ARBs significantly increased step down latencies and decreased latency to reach the platform in target quadrant in young, aged and scopolamine-treated animals in PAT and WMT, respectively. The treatments inhibited acetylcholinesterase (AChE) enzyme in the brain. Similarly, all the treatments attenuated scopolamine-induced lipid peroxidation and normalize antioxidant enzymes. Conclusion: The results suggest that the cognitive enhancing effect of ACEI and ARBs may be due to inhibition of AChE or by regulation of antioxidant system or increase in formation of angiotensin IV. PMID:26069362

Implementation of Tree and Butterfly Barriers with Optimistic Time Management Algorithms for Discrete Event Simulation

NASA Astrophysics Data System (ADS)

Rizvi, Syed S.; Shah, Dipali; Riasat, Aasia

The Time Wrap algorithm [3] offers a run time recovery mechanism that deals with the causality errors. These run time recovery mechanisms consists of rollback, anti-message, and Global Virtual Time (GVT) techniques. For rollback, there is a need to compute GVT which is used in discrete-event simulation to reclaim the memory, commit the output, detect the termination, and handle the errors. However, the computation of GVT requires dealing with transient message problem and the simultaneous reporting problem. These problems can be dealt in an efficient manner by the Samadi's algorithm [8] which works fine in the presence of causality errors. However, the performance of both Time Wrap and Samadi's algorithms depends on the latency involve in GVT computation. Both algorithms give poor latency for large simulation systems especially in the presence of causality errors. To improve the latency and reduce the processor ideal time, we implement tree and butterflies barriers with the optimistic algorithm. Our analysis shows that the use of synchronous barriers such as tree and butterfly with the optimistic algorithm not only minimizes the GVT latency but also minimizes the processor idle time.

An Investigation of Memory Latency Reduction Using an Address Prediction Buffer

DTIC Science & Technology

1992-12-01

McGraw-Hill Inc.. London, England, 1991. [GAJSKI87] Gajski , D.D. et al, Computer Architecture, IEEE Computer Society Press, Washington, D.C., 1987...California, (vol 19 no 3), 1991. [NOWICK92] Nowicki, G ., "Design and Implementation of a Read Prediction Buffer", Master’s Thesis, Naval Postgraduate School

Social cues at encoding affect memory in 4-month-old infants.

PubMed

Kopp, Franziska; Lindenberger, Ulman

2012-01-01

Available evidence suggests that infants use adults' social cues for learning by the second half of the first year of life. However, little is known about the short-term or long-term effects of joint attention interactions on learning and memory in younger infants. In the present study, 4-month-old infants were familiarized with visually presented objects in either of two conditions that differed in the degree of joint attention (high vs. low). Brain activity in response to familiar and novel objects was assessed immediately after the familiarization phase (immediate recognition), and following a 1-week delay (delayed recognition). The latency of the Nc component differentiated between recognition of old versus new objects. Pb amplitude and latency were affected by joint attention in delayed recognition. Moreover, the frequency of infant gaze to the experimenter during familiarization differed between the two experimental groups and modulated the Pb response. Results show that joint attention affects the mechanisms of long-term retention in 4-month-old infants. We conclude that joint attention helps children at this young age to recognize the relevance of learned items.

MLP: A Parallel Programming Alternative to MPI for New Shared Memory Parallel Systems

NASA Technical Reports Server (NTRS)

Taft, James R.

1999-01-01

Recent developments at the NASA AMES Research Center's NAS Division have demonstrated that the new generation of NUMA based Symmetric Multi-Processing systems (SMPs), such as the Silicon Graphics Origin 2000, can successfully execute legacy vector oriented CFD production codes at sustained rates far exceeding processing rates possible on dedicated 16 CPU Cray C90 systems. This high level of performance is achieved via shared memory based Multi-Level Parallelism (MLP). This programming approach, developed at NAS and outlined below, is distinct from the message passing paradigm of MPI. It offers parallelism at both the fine and coarse grained level, with communication latencies that are approximately 50-100 times lower than typical MPI implementations on the same platform. Such latency reductions offer the promise of performance scaling to very large CPU counts. The method draws on, but is also distinct from, the newly defined OpenMP specification, which uses compiler directives to support a limited subset of multi-level parallel operations. The NAS MLP method is general, and applicable to a large class of NASA CFD codes.

Fast, multi-channel real-time processing of signals with microsecond latency using graphics processing units.

PubMed

Rath, N; Kato, S; Levesque, J P; Mauel, M E; Navratil, G A; Peng, Q

2014-04-01

Fast, digital signal processing (DSP) has many applications. Typical hardware options for performing DSP are field-programmable gate arrays (FPGAs), application-specific integrated DSP chips, or general purpose personal computer systems. This paper presents a novel DSP platform that has been developed for feedback control on the HBT-EP tokamak device. The system runs all signal processing exclusively on a Graphics Processing Unit (GPU) to achieve real-time performance with latencies below 8 μs. Signals are transferred into and out of the GPU using PCI Express peer-to-peer direct-memory-access transfers without involvement of the central processing unit or host memory. Tests were performed on the feedback control system of the HBT-EP tokamak using forty 16-bit floating point inputs and outputs each and a sampling rate of up to 250 kHz. Signals were digitized by a D-TACQ ACQ196 module, processing done on an NVIDIA GTX 580 GPU programmed in CUDA, and analog output was generated by D-TACQ AO32CPCI modules.

Radiation Tolerant Intelligent Memory Stack (RTIMS)

NASA Technical Reports Server (NTRS)

Ng, Tak-kwong; Herath, Jeffrey A.

2006-01-01

The Radiation Tolerant Intelligent Memory Stack (RTIMS), suitable for both geostationary and low earth orbit missions, has been developed. The memory module is fully functional and undergoing environmental and radiation characterization. A self-contained flight-like module is expected to be completed in 2006. RTIMS provides reconfigurable circuitry and 2 gigabits of error corrected or 1 gigabit of triple redundant digital memory in a small package. RTIMS utilizes circuit stacking of heterogeneous components and radiation shielding technologies. A reprogrammable field programmable gate array (FPGA), six synchronous dynamic random access memories, linear regulator, and the radiation mitigation circuitries are stacked into a module of 42.7mm x 42.7mm x 13.00mm. Triple module redundancy, current limiting, configuration scrubbing, and single event function interrupt detection are employed to mitigate radiation effects. The mitigation techniques significantly simplify system design. RTIMS is well suited for deployment in real-time data processing, reconfigurable computing, and memory intensive applications.

The MHV68 M2 protein drives IL-10 dependent B cell proliferation and differentiation.

PubMed

Siegel, Andrea M; Herskowitz, Jeremy H; Speck, Samuel H

2008-04-04

Murine gammaherpesvirus 68 (MHV68) establishes long-term latency in memory B cells similar to the human gammaherpesvirus Epstein Barr Virus (EBV). EBV encodes an interleukin-10 (IL-10) homolog and modulates cellular IL-10 expression; however, the role of IL-10 in the establishment and/or maintenance of chronic EBV infection remains unclear. Notably, MHV68 does not encode an IL-10 homolog, but virus infection has been shown to result in elevated serum IL-10 levels in wild-type mice, and IL-10 deficiency results in decreased establishment of virus latency. Here we show that a unique MHV68 latency-associated gene product, the M2 protein, is required for the elevated serum IL-10 levels observed at 2 weeks post-infection. Furthermore, M2 protein expression in primary murine B cells drives high level IL-10 expression along with increased secretion of IL-2, IL-6, and MIP-1alpha. M2 expression was also shown to significantly augment LPS driven survival and proliferation of primary murine B cells. The latter was dependent on IL-10 expression as demonstrated by the failure of IL10-/- B cells to proliferate in response to M2 protein expression and rescue of M2-associated proliferation by addition of recombinant murine IL-10. M2 protein expression in primary B cells also led to upregulated surface expression of the high affinity IL-2 receptor (CD25) and the activation marker GL7, along with down-regulated surface expression of B220, MHC II, and sIgD. The cells retained CD19 and sIgG expression, suggesting differentiation to a pre-plasma memory B cell phenotype. These observations are consistent with previous analyses of M2-null MHV68 mutants that have suggested a role for the M2 protein in expansion and differentiation of MHV68 latently infected B cells-perhaps facilitating the establishment of virus latency in memory B cells. Thus, while the M2 protein is unique to MHV68, analysis of M2 function has revealed an important role for IL-10 in MHV68 pathogenesis-identifying a strategy that appears to be conserved between at least EBV and MHV68.

Tolerance induction of IgG+ memory B cells by T cell-independent type II antigens.

PubMed

Haniuda, Kei; Nojima, Takuya; Ohyama, Kyosuke; Kitamura, Daisuke

2011-05-15

Memory B cells generated during a T cell-dependent immune response rapidly respond to a secondary immunization by producing abundant IgG Abs that bind cognate Ag with high affinity. It is currently unclear whether this heightened recall response by memory B cells is due to augmented IgG-BCR signaling, which has only been demonstrated in the context of naive transgenic B cells. To address this question, we examined whether memory B cells can respond in vivo to Ags that stimulate only through BCR, namely T cell-independent type II (TI-II) Ags. In this study, we show that the TI-II Ag (4-hydroxy-3-nitrophenyl) acetyl (NP)-Ficoll cannot elicit the recall response in mice first immunized with the T cell-dependent Ag NP-chicken γ-globulin. Moreover, the NP-Ficoll challenge in vivo as well as in vitro significantly inhibits a subsequent recall response to NP-chicken γ-globulin in a B cell-intrinsic manner. This NP-Ficoll-mediated tolerance is caused by the preferential elimination of IgG(+) memory B cells binding to NP with high affinity. These data indicate that BCR cross-linking with a TI-II Ag does not activate IgG(+) memory B cells, but rather tolerizes them, identifying a terminal checkpoint of memory B cell differentiation that may prevent autoimmunity.

[Tuberculosis: steady dynamics between past and present to imagine the future].

PubMed

Cabello C, Felipe

2011-07-01

Progress in understanding the biological processes that allow Mycobacterium tuberculosis to be a successful parasite have accelerated in the last twenty years. This progress has been stimulated by the return of tuberculosis (TB) as an important disease in industrialized countries, by its increase in emergent nations in the tail of population increases and poverty and by the spread of multiple drug resistant (MDR) and extensively drug resistant (XDR) M. tuberculosis as a result of treatment failures. Progress on M. tuberculosis biology has also been fueled by advances in microbiology and molecular biology, including molecular genetics, genomics, proteomics and in vitro and in vivo models of infection. The study of latency or dormancy, a phenomenon central to understanding the persistence of M. tuberculosis and the development of TB in individuals, its spread in human populations and the emergence of antibiotic-resistant/tolerant organisms, has been preferred targets for investigators in this area. In this manner, factors that trigger M. tuberculosis latency (e. g, hypoxia, nutrient starvation, NO exposure) have been characterized and the metabolic shifts to host lipid utilization, tolerance to antimicrobials and resistance to host immune mechanisms involved in latency have been determined. Similarly, genetic changes and the resulting antimicrobial mechanisms mediating the MDR and XDR states have been characterized and potential new vaccines that avoid reactivation from latency and infection are being developed. Despite this progress, and given the fact that effective anti tuberculosis therapy was developed and first introduced clinically at the end of the 1940s, there are now more cases of latent and active TB worldwide than ever before. This reinforces the concept of TB as a bacterial disease with strong social and economical! determinants which are presently stimulating increased transmission in many human groups, undermining diagnostics, treatment and prevention. It suggests that in a scenario of global economical crisis the struggle against TB will be weakened, unless efforts are included to alleviate poverty, decrease economic inequality, improve public health and allow democracy and political organization.

Pharmacological validation of in-silico guided novel nootropic potential of Achyranthes aspera L.

PubMed

Gawande, Dinesh Yugraj; Goel, Rajesh Kumar

2015-12-04

Achyranthes aspera (A. aspera) has been used as a brain tonic in folk medicine. Although, ethnic use of medicinal plant has been basis for drug discovery from medicinal plants, but the available in-silico tools can be useful to find novel pharmacological uses of medicinal plants beyond their ethnic use. To validate in-silico prediction for novel nootropic effect of A. aspera by employing battery of tests in mice. Phytoconstituents of A. aspera reported in Dictionary of Natural Product were subjected to in-silico prediction using PASS and Pharmaexpert. The nootropic activity predicted for A. aspera was assessed using radial arm maze, passive shock avoidance and novel object recognition tests in mice. After behavioral evaluation animals were decapitated and their brains were collected and stored for estimation of glutamate levels and acetylcholinesterase activity. In-silico activity spectrum for majority of A. aspera phytoconstituents exhibited excellent prediction score for nootropic activity of this plant. A. aspera extract treatment significantly improved the learning and memory as evident by decreased working memory errors, reference memory errors and latency time in radial arm maze, step through latency in passive shock avoidance and increased recognition index in novel object recognition were observed, moreover significantly enhanced glutamate levels and reduced acetylcholinesterase activity in hippocampus and cortex were observed as compared to the saline treated group. In-silico and in-vivo results suggest that A. aspera plant may improve the learning and memory by modulating the brain glutamatergic and cholinergic neurotransmission. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Barnes maze testing strategies with small and large rodent models.

PubMed

Rosenfeld, Cheryl S; Ferguson, Sherry A

2014-02-26

Spatial learning and memory of laboratory rodents is often assessed via navigational ability in mazes, most popular of which are the water and dry-land (Barnes) mazes. Improved performance over sessions or trials is thought to reflect learning and memory of the escape cage/platform location. Considered less stressful than water mazes, the Barnes maze is a relatively simple design of a circular platform top with several holes equally spaced around the perimeter edge. All but one of the holes are false-bottomed or blind-ending, while one leads to an escape cage. Mildly aversive stimuli (e.g. bright overhead lights) provide motivation to locate the escape cage. Latency to locate the escape cage can be measured during the session; however, additional endpoints typically require video recording. From those video recordings, use of automated tracking software can generate a variety of endpoints that are similar to those produced in water mazes (e.g. distance traveled, velocity/speed, time spent in the correct quadrant, time spent moving/resting, and confirmation of latency). Type of search strategy (i.e. random, serial, or direct) can be categorized as well. Barnes maze construction and testing methodologies can differ for small rodents, such as mice, and large rodents, such as rats. For example, while extra-maze cues are effective for rats, smaller wild rodents may require intra-maze cues with a visual barrier around the maze. Appropriate stimuli must be identified which motivate the rodent to locate the escape cage. Both Barnes and water mazes can be time consuming as 4-7 test trials are typically required to detect improved learning and memory performance (e.g. shorter latencies or path lengths to locate the escape platform or cage) and/or differences between experimental groups. Even so, the Barnes maze is a widely employed behavioral assessment measuring spatial navigational abilities and their potential disruption by genetic, neurobehavioral manipulations, or drug/ toxicant exposure.

Messier: A Detailed NVM-Based DIMM Model for the SST Simulation Framework.

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

Awad, Amro; Voskuilen, Gwendolyn Renae; Rodrigues, Arun F.

2017-02-01

DRAM technology is the main building block of main memory, however, DRAM scaling is becoming very challenging. The main issues for DRAM scaling are the increasing error rates with each new generation, the geometric and physical constraints of scaling the capacitor part of the DRAM cells, and the high power consumption caused by the continuous need for refreshing cell values. At the same time, emerging Non- Volatile Memory (NVM) technologies, such as Phase-Change Memory (PCM), are emerging as promising replacements for DRAM. NVMs, when compared to current technologies e.g., NAND-based ash, have latencies comparable to DRAM. Additionally, NVMs are non-volatile,more » which eliminates the need for refresh power and enables persistent memory applications. Finally, NVMs have promising densities and the potential for multi-level cell (MLC) storage.« less

Protective role of Delphinium denudatum (Jadwar) against morphine induced tolerance and dependence in mice.

PubMed

Zafar, S; Ahmad, M A; Siddiqui, T A

2001-11-01

Chronic treatment with Delphinium denudatum (Dd) (Jadwar) (family: Ranunculaceae, 200-1600 mg/kg) suppressed morphine withdrawal jumps in a dose-dependent manner, a sign of the development of dependence to opiate as assessed by naloxone (2 mg/kg) precipitation withdrawal on day 10 of testing in mice. Repeated administration of Dd (200-1600 mg/kg) for 9 days attenuated the development of tolerance to the analgesic effect of morphine (10 mg/kg), also produces significant change in tail-flick latency from the saline pretreated group in a dose-dependent manner.

ACUTE AND REPEATED INHALATION OF TOLUENE BY RATS PERFORMING A SIGNAL DETECTION TASK LEADS TO BEHAVIORAL TOLERANCE ON SOME PERFORMANCE MEASURES.

EPA Science Inventory

Previous work showed that trichloroethylene (TCE) impairs accuracy and latency in a signal detection task (SDT) in rats, and that these effects abate during repeated exposures if rats inhale TCE during SDT testing. The present experiment compared the effects of acute and repeated...

The contribution of encoding and retrieval processes to proactive interference.

PubMed

Kliegl, Oliver; Pastötter, Bernhard; Bäuml, Karl-Heinz T

2015-11-01

Proactive interference (PI) refers to the finding that memory for recently studied (target) material can be impaired by the prior study of other (nontarget) material. Previous accounts of PI differed in whether they attributed PI to impaired retrieval or impaired encoding. Here, we suggest an integrated encoding-retrieval account, which assigns a role for each of the 2 types of processes in buildup of PI. Employing a typical PI task, we examined (a) the role of encoding processes in PI by recording scalp EEG during study of nontarget and target lists, and (b) the role of retrieval processes in PI by measuring recall totals and response latencies in target list recall. In addition, we measured subjects' working memory capacity (WMC). Behaviorally, the PI effect arose in both recall totals and response latencies, indicating PI at the sampling and the recovery stage of recall. Neurally, we found an increase in electrophysiological activities in the theta frequency band (5-8 Hz) from nontarget to target list encoding, indicating an increase in memory load during target list encoding. The results demonstrate that impaired retrieval and impaired encoding can contribute to PI. They also show that WMC affects PI. For both encoding and retrieval processes, PI was reduced in high-WMC subjects, suggesting that these subjects are able to separate target from nontarget information and create stronger focus on the target material. (c) 2015 APA, all rights reserved).

Alterations in fear response and spatial memory in pre- and post-natal zinc supplemented rats: remediation by copper.

PubMed

Railey, Angela M; Micheli, Teresa L; Wanschura, Patricia B; Flinn, Jane M

2010-05-11

The role of zinc in the nervous system is receiving increased attention. At a time when dietary fortification and supplementation have increased the amount of zinc being consumed, little work has been done on the effects of enhanced zinc on behavior. Both zinc and copper are essential trace minerals that are acquired from the diet; under normal conditions the body protects against zinc overload, but at excessive dosages, copper deficiency has been seen. In order to examine the effect of enhanced metal administration on learning and memory, Sprague Dawley rats were given water supplemented with 10ppm Zn, 10ppm Zn+0.25ppm Cu, or normal lab water, during pre- and post-natal development. Fear conditioning tests at 4months showed significantly higher freezing rates during contextual retention and extinction and cued extinction for rats drinking water supplemented with zinc, suggesting increased anxiety compared to controls raised on lab water. During the MWM task at 9months, zinc-enhanced rats had significantly longer latencies to reach the platform compared to controls. The addition of copper to the zinc supplemented water brought freezing and latency levels closer to that of controls. These data demonstrate the importance of maintaining appropriate intake of both metals simultaneously, and show that long-term supplementation with zinc may cause alterations in memory. Copyright 2010 Elsevier Inc. All rights reserved.

The involvement of medial septum 5-HT1 and 5-HT2 receptors on ACPA-induced memory consolidation deficit: possible role of TRPC3, TRPC6 and TRPV2.

PubMed

Najar, Farzaneh; Nasehi, Mohammad; Haeri-Rohani, Seyed-Ali; Zarrindast, Mohammad-Reza

2015-11-01

The present study evaluates the roles of serotonergic receptors of the medial septum on amnesia induced by arachidonylcyclopropylamide (ACPA; as selective cannabinoid CB1 receptor agonist) in adult male Wistar rats. Cannulae were implanted in the medial septum of the brain of the rats. The animals were trained in a passive avoidance learning apparatus, and were tested 24 hours after training for step-through latency. Results indicated that post-training medial septum administration of CP94253 (5-HT1B/1D receptor agonist) and cinancerine (as 5-HT2 receptor antagonist) reduced the step-through latency showing an amnesic response, while GR127935 (5-HT1B/1D receptor antagonist) and αm5htm (as 5-HT2A/2B/2D receptor agonist) did not alter memory consolidation by themselves. On continuing the test, the results showed that CP94253 increased and GR127935 did not alter ACPA (0.02 µg/rat)-induced memory impairment, respectively. Other data indicated that αm5htm induced a modulatory effect, while cinancerine restored ACPA-induced amnesia. Using SKF-96365 (inhibitor of transient receptor potential TRPC3/6 and TRPV2 channels) demonstrated that TRPC3, TRPC3 and TRPV2 channels have a significant role, according to our results. © The Author(s) 2015.

Electronic Sleep Stage Classifiers: A Survey and VLSI Design Methodology.

PubMed

Kassiri, Hossein; Chemparathy, Aditi; Salam, M Tariqus; Boyce, Richard; Adamantidis, Antoine; Genov, Roman

2017-02-01

First, existing sleep stage classifier sensors and algorithms are reviewed and compared in terms of classification accuracy, level of automation, implementation complexity, invasiveness, and targeted application. Next, the implementation of a miniature microsystem for low-latency automatic sleep stage classification in rodents is presented. The classification algorithm uses one EMG (electromyogram) and two EEG (electroencephalogram) signals as inputs in order to detect REM (rapid eye movement) sleep, and is optimized for low complexity and low power consumption. It is implemented in an on-board low-power FPGA connected to a multi-channel neural recording IC, to achieve low-latency (order of 1 ms or less) classification. Off-line experimental results using pre-recorded signals from nine mice show REM detection sensitivity and specificity of 81.69% and 93.86%, respectively, with the maximum latency of 39 [Formula: see text]. The device is designed to be used in a non-disruptive closed-loop REM sleep suppression microsystem, for future studies of the effects of REM sleep deprivation on memory consolidation.

Conditioned allophony in speech perception: an ERP study.

PubMed

Miglietta, Sandra; Grimaldi, Mirko; Calabrese, Andrea

2013-09-01

A Mismatch Negativity (MMN) study was performed to investigate whether pre-attentive vowel perception is influenced by phonological status. We compared the MMN response to the acoustic distinction between the allophonic variation [ε-e] and phonemic contrast [e-i] present in a Southern-Italian variety (Tricase dialect). Clear MMNs were elicited for both the phonemic and allophonic conditions. Interestingly, a shorter latency was observed for the phonemic pair, but no significant amplitude difference was observed between the two conditions. Together, these results suggest that for isolated vowels, the phonological status of a vowel category is reflected in the latency of the MMN peak. The earlier latency of the phonemic condition argues for an easier parsing and encoding of phonemic contrasts in memory representations. Thus, neural computations mapping auditory inputs into higher perceptual representations seem 'sensitive' to the contrastive/non-contrastive status of the sounds as determined by the listeners' knowledge of the own phonological system. Copyright © 2013 Elsevier Inc. All rights reserved.

Implementation Of The Configurable Fault Tolerant System Experiment On NPSAT 1

DTIC Science & Technology

2016-03-01

REPORT TYPE AND DATES COVERED Master’s thesis 4. TITLE AND SUBTITLE IMPLEMENTATION OF THE CONFIGURABLE FAULT TOLERANT SYSTEM EXPERIMENT ON NPSAT...open-source microprocessor without interlocked pipeline stages (MIPS) based processor softcore, a cached memory structure capable of accessing double...data rate type three and secure digital card memories, an interface to the main satellite bus, and XILINX’s soft error mitigation softcore. The

Cooperative Data Sharing: Simple Support for Clusters of SMP Nodes

NASA Technical Reports Server (NTRS)

DiNucci, David C.; Balley, David H. (Technical Monitor)

1997-01-01

Libraries like PVM and MPI send typed messages to allow for heterogeneous cluster computing. Lower-level libraries, such as GAM, provide more efficient access to communication by removing the need to copy messages between the interface and user space in some cases. still lower-level interfaces, such as UNET, get right down to the hardware level to provide maximum performance. However, these are all still interfaces for passing messages from one process to another, and have limited utility in a shared-memory environment, due primarily to the fact that message passing is just another term for copying. This drawback is made more pertinent by today's hybrid architectures (e.g. clusters of SMPs), where it is difficult to know beforehand whether two communicating processes will share memory. As a result, even portable language tools (like HPF compilers) must either map all interprocess communication, into message passing with the accompanying performance degradation in shared memory environments, or they must check each communication at run-time and implement the shared-memory case separately for efficiency. Cooperative Data Sharing (CDS) is a single user-level API which abstracts all communication between processes into the sharing and access coordination of memory regions, in a model which might be described as "distributed shared messages" or "large-grain distributed shared memory". As a result, the user programs to a simple latency-tolerant abstract communication specification which can be mapped efficiently to either a shared-memory or message-passing based run-time system, depending upon the available architecture. Unlike some distributed shared memory interfaces, the user still has complete control over the assignment of data to processors, the forwarding of data to its next likely destination, and the queuing of data until it is needed, so even the relatively high latency present in clusters can be accomodated. CDS does not require special use of an MMU, which can add overhead to some DSM systems, and does not require an SPMD programming model. unlike some message-passing interfaces, CDS allows the user to implement efficient demand-driven applications where processes must "fight" over data, and does not perform copying if processes share memory and do not attempt concurrent writes. CDS also supports heterogeneous computing, dynamic process creation, handlers, and a very simple thread-arbitration mechanism. Additional support for array subsections is currently being considered. The CDS1 API, which forms the kernel of CDS, is built primarily upon only 2 communication primitives, one process initiation primitive, and some data translation (and marshalling) routines, memory allocation routines, and priority control routines. The entire current collection of 28 routines provides enough functionality to implement most (or all) of MPI 1 and 2, which has a much larger interface consisting of hundreds of routines. still, the API is small enough to consider integrating into standard os interfaces for handling inter-process communication in a network-independent way. This approach would also help to solve many of the problems plaguing other higher-level standards such as MPI and PVM which must, in some cases, "play OS" to adequately address progress and process control issues. The CDS2 API, a higher level of interface roughly equivalent in functionality to MPI and to be built entirely upon CDS1, is still being designed. It is intended to add support for the equivalent of communicators, reduction and other collective operations, process topologies, additional support for process creation, and some automatic memory management. CDS2 will not exactly match MPI, because the copy-free semantics of communication from CDS1 will be supported. CDS2 application programs will be free to carefully also use CDS1. CDS1 has been implemented on networks of workstations running unmodified Unix-based operating systems, using UDP/IP and vendor-supplied high- performance locks. Although its inter-node performance is currently unimpressive due to rudimentary implementation technique, it even now outperforms highly-optimized MPI implementation on intra-node communication due to its support for non-copy communication. The similarity of the CDS1 architecture to that of other projects such as UNET and TRAP suggests that the inter-node performance can be increased significantly to surpass MPI or PVM, and it may be possible to migrate some of its functionality to communication controllers.

The role of spatial selective attention in working memory for locations: evidence from event-related potentials.

PubMed

Awh, E; Anllo-Vento, L; Hillyard, S A

2000-09-01

We investigated the hypothesis that the covert focusing of spatial attention mediates the on-line maintenance of location information in spatial working memory. During the delay period of a spatial working-memory task, behaviorally irrelevant probe stimuli were flashed at both memorized and nonmemorized locations. Multichannel recordings of event-related potentials (ERPs) were used to assess visual processing of the probes at the different locations. Consistent with the hypothesis of attention-based rehearsal, early ERP components were enlarged in response to probes that appeared at memorized locations. These visual modulations were similar in latency and topography to those observed after explicit manipulations of spatial selective attention in a parallel experimental condition that employed an identical stimulus display.

Event-related potentials elicited during working memory are altered in mild cognitive impairment.

PubMed

López Zunini, Rocío A; Knoefel, Frank; Lord, Courtney; Dzuali, Fiatsogbe; Breau, Michael; Sweet, Lisa; Goubran, Rafik; Taler, Vanessa

2016-11-01

Persons with Mild Cognitive Impairment (MCI) can experience deficits in working memory. In the present study, we investigated working memory in persons with MCI and cognitively healthy older adults using event-related potentials (ERPs). Participants performed an n-back working memory task with baseline (0-back), low load (1-back), and high load (2-back) working memory conditions. MCI participants' performance was less accurate than that of healthy older adults in both the 1-back and 2-back conditions, and reaction times were longer in MCI than control participants in the 0-back, 1-back and 2-back conditions. ERP analyses revealed delayed P200 and N200 latencies and smaller P300 amplitudes in MCI relative to control participants in the 0-back, 1-back and 2-back conditions. Deterioration in working memory performance concomitant with marked electrophysiological alterations suggests that persons with MCI exhibit deficits in several cognitive processes that include early attention, stimulus discrimination and classification, and updating and manipulation of information held in working memory. Copyright © 2016 Elsevier B.V. All rights reserved.

[Autobiographical memory of depressed patients].

PubMed

Yao, Shuqiao; Liu, Xianhua; Zhao, Weifeng; Yang, Wenhui; Tan, Furong

2010-07-01

To explore the autobiographical memory characteristics in depressed patients and their influence factors. Autobiographical memory, emotion and cognitive executive function of 60 depressed patients and 60 healthy controls were assessed with autobiographical memory test (AMT), Hamilton depression scale (HAMD), Beck depression inventory (BDI), Beck anxiety inventory (BAI), hospital anxiety and depression scale (HAD), arrow-task stroop test (ATST), Wisconsin card sorting test (WCST), Backward masking test (BMT) and continuous performance test (CPT). The specific memory of the depressed group was significantly less than that of the control group, and was negatively related with the negative emotion score, the time of anterograde and retrograde reading of ATST, and the time difference of ATST. The overgeneral memory increased and the latency to response of ATST was significantly longer than that of the control group. The two factors were positively related with the negative emotion score, the time of anterograde and retrograde reading of ATST, and the time difference of ATST. The autobiographical memory of the depressed patients is overgeneralized and retarded. These characteristics are related with negative emotion and impairment of cognitive executive function.

The role of emotional engagement and mood valence in retrieval fluency of mood incongruent autobiographical memory

PubMed Central

Greenberg, Jonathan; Meiran, Nachshon

2014-01-01

Background: Retrieval of opposite mood autobiographical memories serves emotion regulation, yet the factors influencing this ability are poorly understood. Methods: Three studies examined the effect of mood valence (sad vs. happy) and degree of emotional engagement on fluency of mood incongruent retrieval by manipulating emotional engagement and examining the effect of emotional film clips on the Fluency of Autobiographical Memory task. Results: Following both sad and happy film clips, participants who received emotionally engaging instructions exhibited a greater recall latency of the first opposite mood memory, and had generated less such memories than those receiving emotionally disengaging instructions (Studies 1 and 2). A happy mood induction resulted in recollection of fewer mood incongruent memories compared to a sad mood induction. Providing emotionally engaging instructions was found to specifically hinder mood incongruent retrieval, without impairing mood congruent retrieval (Study 3). Conclusion: High emotional engagement seems to impair the retrieval of mood incongruent memories. Being in a happy mood may also partially impair such retrieval. Implications regarding emotional regulation are discussed. PMID:24570671

Integrated analysis of error detection and recovery

NASA Technical Reports Server (NTRS)

Shin, K. G.; Lee, Y. H.

1985-01-01

An integrated modeling and analysis of error detection and recovery is presented. When fault latency and/or error latency exist, the system may suffer from multiple faults or error propagations which seriously deteriorate the fault-tolerant capability. Several detection models that enable analysis of the effect of detection mechanisms on the subsequent error handling operations and the overall system reliability were developed. Following detection of the faulty unit and reconfiguration of the system, the contaminated processes or tasks have to be recovered. The strategies of error recovery employed depend on the detection mechanisms and the available redundancy. Several recovery methods including the rollback recovery are considered. The recovery overhead is evaluated as an index of the capabilities of the detection and reconfiguration mechanisms.

Investigating Trauma in Narrating World War I: A Psychoanalytical Reading of Pat Barker's "Regeneration"

ERIC Educational Resources Information Center

Sadjadi, Bakhtiar; Esmkhani, Farnaz

2016-01-01

The present paper seeks to critically read Pat Barker's "Regeneration" in terms of Cathy Caruth's psychoanalytic study of trauma. This analysis attempts to trace the concepts of latency, post-traumatic stress disorders, traumatic memory, and trauma in Barker's novel in order to explore how trauma and history are interrelated in the…

Gypenosides ameliorate memory deficits in MPTP-lesioned mouse model of Parkinson's disease treated with L-DOPA.

PubMed

Zhao, Ting Ting; Kim, Kyung Sook; Shin, Keon Sung; Park, Hyun Jin; Kim, Hyun Jeong; Lee, Kyung Eun; Lee, Myung Koo

2017-09-06

Previous studies have revealed that gypenosides (GPS) improve the symptoms of anxiety disorders in a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-lesioned rat model of Parkinson's disease (PD). The present study aimed to investigate the effects of GPS on memory deficits in an MPTP-lesioned mouse model of PD treated with L-3,4-dihydroxyphenylalanine (L-DOPA). MPTP (30 mg/kg/day, 5 days)-lesioned mice were treated with GPS (50 mg/kg) and/or L-DOPA (10 and 25 mg/kg) for 21 days. After the final treatments, behavioral changes were assessed in all mice using passive avoidance and elevated plus-maze tests. We then evaluated the biochemical influences of GPS treatment on levels of tyrosine hydroxylase (TH), dopamine, N-methyl-D-aspartate (NMDA) receptors, extracellular signal-regulated kinase (ERK1/2), and cyclic AMP-response element binding protein (CREB) phosphorylation. MPTP-lesioned mice exhibited deficits associated with habit learning and spatial memory, which were further aggravated by treatment with L-DOPA (25 mg/kg). However, treatment with GPS (50 mg/kg) ameliorated memory deficits. Treatment with GPS (50 mg/kg) also improved L-DOPA (25 mg/kg)-treated MPTP lesion-induced decreases in retention latency on the passive avoidance test, as well as levels of TH-immunopositive cells and dopamine in the substantia nigra and striatum. GPS treatment also attenuated increases in retention transfer latency on the elevated plus-maze test and in NMDA receptor expression, as well as decreases in the phosphorylation of ERK1/2 and CREB in the hippocampus. Treatment with L-DOPA (10 mg/kg) also ameliorated deficits in habit learning and spatial memory in MPTP-lesioned mice, and this effect was further enhanced by treatment with GPS (50 mg/kg). GPS ameliorate deficits in habit learning and spatial memory by modulating the dopaminergic neuronal and N-methyl-D-aspartate receptor-mediated signaling systems in MPTP-lesioned mice treated with L-DOPA. GPS may serve as an adjuvant therapeutic agent for memory deficits in patients with PD receiving L-DOPA.

Braid read-only memory

NASA Technical Reports Server (NTRS)

Mckenna, J. F.

1973-01-01

Transformer-type memory is fault-tolerant array of independent read-only memory units. Information pattern in each unit is written by weaving wires through array of linear (nonswitching) transformers. Presence or absence of a bit is determined by whether a given wire threads or bypasses given transformer.

Gender Dimorphism in Aspartame-Induced Impairment of Spatial Cognition and Insulin Sensitivity

PubMed Central

Collison, Kate S.; Makhoul, Nadine J.; Zaidi, Marya Z.; Saleh, Soad M.; Andres, Bernard; Inglis, Angela; Al-Rabiah, Rana; Al-Mohanna, Futwan A.

2012-01-01

Previous studies have linked aspartame consumption to impaired retention of learned behavior in rodents. Prenatal exposure to aspartame has also been shown to impair odor-associative learning in guinea pigs; and recently, aspartame-fed hyperlipidemic zebrafish exhibited weight gain, hyperglycemia and acute swimming defects. We therefore investigated the effects of chronic lifetime exposure to aspartame, commencing in utero, on changes in blood glucose parameters, spatial learning and memory in C57BL/6J mice. Morris Water Maze (MWM) testing was used to assess learning and memory, and a random-fed insulin tolerance test was performed to assess glucose homeostasis. Pearson correlation analysis was used to investigate the associations between body characteristics and MWM performance outcome variables. At 17 weeks of age, male aspartame-fed mice exhibited weight gain, elevated fasting glucose levels and decreased insulin sensitivity compared to controls (P<0.05). Females were less affected, but had significantly raised fasting glucose levels. During spatial learning trials in the MWM (acquisition training), the escape latencies of male aspartame-fed mice were consistently higher than controls, indicative of learning impairment. Thigmotactic behavior and time spent floating directionless was increased in aspartame mice, who also spent less time searching in the target quadrant of the maze (P<0.05). Spatial learning of female aspartame-fed mice was not significantly different from controls. Reference memory during a probe test was affected in both genders, with the aspartame-fed mice spending significantly less time searching for the former location of the platform. Interestingly, the extent of visceral fat deposition correlated positively with non-spatial search strategies such as floating and thigmotaxis, and negatively with time spent in the target quadrant and swimming across the location of the escape platform. These data suggest that lifetime exposure to aspartame, commencing in utero, may affect spatial cognition and glucose homeostasis in C57BL/6J mice, particularly in males. PMID:22509243

Gender dimorphism in aspartame-induced impairment of spatial cognition and insulin sensitivity.

PubMed

Collison, Kate S; Makhoul, Nadine J; Zaidi, Marya Z; Saleh, Soad M; Andres, Bernard; Inglis, Angela; Al-Rabiah, Rana; Al-Mohanna, Futwan A

2012-01-01

Previous studies have linked aspartame consumption to impaired retention of learned behavior in rodents. Prenatal exposure to aspartame has also been shown to impair odor-associative learning in guinea pigs; and recently, aspartame-fed hyperlipidemic zebrafish exhibited weight gain, hyperglycemia and acute swimming defects. We therefore investigated the effects of chronic lifetime exposure to aspartame, commencing in utero, on changes in blood glucose parameters, spatial learning and memory in C57BL/6J mice. Morris Water Maze (MWM) testing was used to assess learning and memory, and a random-fed insulin tolerance test was performed to assess glucose homeostasis. Pearson correlation analysis was used to investigate the associations between body characteristics and MWM performance outcome variables. At 17 weeks of age, male aspartame-fed mice exhibited weight gain, elevated fasting glucose levels and decreased insulin sensitivity compared to controls (P<0.05). Females were less affected, but had significantly raised fasting glucose levels. During spatial learning trials in the MWM (acquisition training), the escape latencies of male aspartame-fed mice were consistently higher than controls, indicative of learning impairment. Thigmotactic behavior and time spent floating directionless was increased in aspartame mice, who also spent less time searching in the target quadrant of the maze (P<0.05). Spatial learning of female aspartame-fed mice was not significantly different from controls. Reference memory during a probe test was affected in both genders, with the aspartame-fed mice spending significantly less time searching for the former location of the platform. Interestingly, the extent of visceral fat deposition correlated positively with non-spatial search strategies such as floating and thigmotaxis, and negatively with time spent in the target quadrant and swimming across the location of the escape platform. These data suggest that lifetime exposure to aspartame, commencing in utero, may affect spatial cognition and glucose homeostasis in C57BL/6J mice, particularly in males.

Search strategy selection in the Morris water maze indicates allocentric map formation during learning that underpins spatial memory formation.

PubMed

Rogers, Jake; Churilov, Leonid; Hannan, Anthony J; Renoir, Thibault

2017-03-01

Using a Matlab classification algorithm, we demonstrate that a highly salient distal cue array is required for significantly increased likelihoods of spatial search strategy selection during Morris water maze spatial learning. We hypothesized that increased spatial search strategy selection during spatial learning would be the key measure demonstrating the formation of an allocentric map to the escape location. Spatial memory, as indicated by quadrant preference for the area of the pool formally containing the hidden platform, was assessed as the main measure that this allocentric map had formed during spatial learning. Our C57BL/6J wild-type (WT) mice exhibit quadrant preference in the highly salient cue paradigm but not the low, corresponding with a 120% increase in the odds of a spatial search strategy selection during learning. In contrast, quadrant preference remains absent in serotonin 1A receptor (5-HT 1A R) knockout (KO) mice, who exhibit impaired search strategy selection during spatial learning. Additionally, we also aimed to assess the impact of the quality of the distal cue array on the spatial learning curves of both latency to platform and path length using mixed-effect regression models and found no significant associations or interactions. In contrast, we demonstrated that the spatial learning curve for search strategy selection was absent during training in the low saliency paradigm. Therefore, we propose that allocentric search strategy selection during spatial learning is the learning parameter in mice that robustly indicates the formation of a cognitive map for the escape goal location. These results also suggest that both latency to platform and path length spatial learning curves do not discriminate between allocentric and egocentric spatial learning and do not reliably predict spatial memory formation. We also show that spatial memory, as indicated by the absolute time in the quadrant formerly containing the hidden platform alone (without reference to the other areas of the pool), was not sensitive to cue saliency or impaired in 5-HT 1A R KO mice. Importantly, in the absence of a search strategy analysis, this suggests that to establish that the Morris water maze has worked (i.e. control mice have formed an allocentric map to the escape goal location), a measure of quadrant preference needs to be reported to establish spatial memory formation. This has implications for studies that claim hippocampal functioning is impaired using latency to platform or path length differences within the existing Morris water maze literature. Copyright © 2016 Elsevier Inc. All rights reserved.

Melatonin for Sleep in Children with Autism: A Controlled Trial Examining Dose, Tolerability, and Outcomes

PubMed Central

Malow, Beth A.; Adkins, Karen W.; McGrew, Susan G.; Wang, Lily; Goldman, Suzanne E.; Fawkes, Diane; Burnette, Courtney

2011-01-01

Supplemental melatonin has shown promise in treating sleep onset insomnia in children with autism spectrum disorders (ASD). Twenty-four children, free of psychotropic medications, completed an open-label dose-escalation study to assess dose-response, tolerability, safety, feasibility of collecting actigraphy data, and ability of outcome measures to detect change during a 14-week intervention. Supplemental melatonin improved sleep latency, as measured by actigraphy, in most children at 1 or 3 mg dosages. It was effective in week 1 of treatment, maintained effects over several months, was well tolerated and safe, and showed improvement in sleep, behavior, and parenting stress. Our findings contribute to the growing literature on supplemental melatonin for insomnia in ASD and inform planning for a large randomized trial in this population. PMID:22160300

Melatonin for sleep in children with autism: a controlled trial examining dose, tolerability, and outcomes.

PubMed

Malow, Beth; Adkins, Karen W; McGrew, Susan G; Wang, Lily; Goldman, Suzanne E; Fawkes, Diane; Burnette, Courtney

2012-08-01

Supplemental melatonin has shown promise in treating sleep onset insomnia in children with autism spectrum disorders (ASD). Twenty-four children, free of psychotropic medications, completed an open-label dose-escalation study to assess dose-response, tolerability, safety, feasibility of collecting actigraphy data, and ability of outcome measures to detect change during a 14-week intervention. Supplemental melatonin improved sleep latency, as measured by actigraphy, in most children at 1 or 3 mg dosages. It was effective in week 1 of treatment, maintained effects over several months, was well tolerated and safe, and showed improvement in sleep, behavior, and parenting stress. Our findings contribute to the growing literature on supplemental melatonin for insomnia in ASD and inform planning for a large randomized trial in this population.

Method of data communications with reduced latency

DOEpatents

Blocksome, Michael A; Parker, Jeffrey J

2013-11-05

Data communications with reduced latency, including: writing, by a producer, a descriptor and message data into at least two descriptor slots of a descriptor buffer, the descriptor buffer comprising allocated computer memory segmented into descriptor slots, each descriptor slot having a fixed size, the descriptor buffer having a header pointer that identifies a next descriptor slot to be processed by a DMA controller, the descriptor buffer having a tail pointer that identifies a descriptor slot for entry of a next descriptor in the descriptor buffer; recording, by the producer, in the descriptor a value signifying that message data has been written into descriptor slots; and setting, by the producer, in dependence upon the recorded value, a tail pointer to point to a next open descriptor slot.

Real time algorithms for sharp wave ripple detection.

PubMed

Sethi, Ankit; Kemere, Caleb

2014-01-01

Neural activity during sharp wave ripples (SWR), short bursts of co-ordinated oscillatory activity in the CA1 region of the rodent hippocampus, is implicated in a variety of memory functions from consolidation to recall. Detection of these events in an algorithmic framework, has thus far relied on simple thresholding techniques with heuristically derived parameters. This study is an investigation into testing and improving the current methods for detection of SWR events in neural recordings. We propose and profile methods to reduce latency in ripple detection. Proposed algorithms are tested on simulated ripple data. The findings show that simple realtime algorithms can improve upon existing power thresholding methods and can detect ripple activity with latencies in the range of 10-20 ms.

Fault-tolerant computer study. [logic designs for building block circuits

NASA Technical Reports Server (NTRS)

Rennels, D. A.; Avizienis, A. A.; Ercegovac, M. D.

1981-01-01

A set of building block circuits is described which can be used with commercially available microprocessors and memories to implement fault tolerant distributed computer systems. Each building block circuit is intended for VLSI implementation as a single chip. Several building blocks and associated processor and memory chips form a self checking computer module with self contained input output and interfaces to redundant communications buses. Fault tolerance is achieved by connecting self checking computer modules into a redundant network in which backup buses and computer modules are provided to circumvent failures. The requirements and design methodology which led to the definition of the building block circuits are discussed.

An Incremental Life-cycle Assurance Strategy for Critical System Certification

DTIC Science & Technology

2014-11-04

for Safe Aircraft Operation Embedded software systems introduce a new class of problems not addressed by traditional system modeling & analysis...Platform Runtime Architecture Application Software Embedded SW System Engineer Data Stream Characteristics Latency jitter affects control behavior...do system level failures still occur despite fault tolerance techniques being deployed in systems ? Embedded software system as major source of

Integrated Environment for Development and Assurance

DTIC Science & Technology

2015-01-26

Jan 26, 2015 © 2015 Carnegie Mellon University We Rely on Software for Safe Aircraft Operation Embedded software systems introduce a new class of...eveloper Compute Platform Runtime Architecture Application Software Embedded SW System Engineer Data Stream Characteristics Latency jitter affects...Why do system level failures still occur despite fault tolerance techniques being deployed in systems ? Embedded software system as major source of

Indiplon in the management of insomnia

PubMed Central

Lemon, Michael D; Strain, Joe D; Hegg, Annie M; Farver, Debra K

2009-01-01

Indiplon is a novel pyrazolopyrimidine, nonbenzodiazepine γ-aminobutyric acid (GABA) agonist studied for the treatment of insomnia. This article reviews the chemistry, pharmacology, clinical pharmacokinetics, drug interactions, clinical trials, safety, tolerability, contraindications, use in special populations, and dosing of indiplon. OVID, International Pharmaceutical Abstracts (IPA), and PubMed databases were searched (1966 to February 2009) for the keywords indiplon, NBI-34060, and insomnia. References of key articles were also reviewed to identify additional publications. Only English language articles were selected for review. Indiplon has been shown to have high affinity and selectivity for the GABAα1 receptor subunit associated with sedation. In clinical studies, indiplon has demonstrated efficacy in improving latency to sleep onset, latency to persistent sleep, total sleep time, wake time after sleep onset, number of awakenings after sleep onset, and overall sleep quality when compared to placebo. Indiplon has a favorable safety profile with limited rebound insomnia and no tolerance. Neurocrine Biosciences, Incorporated received an Approvable Letter from the United States Food and Drug Administration in December 2007 for the indiplon IR 5 mg and 10 mg capsules based on meeting three additional requirements. At the time of this writing, indiplon remains unapproved. PMID:19920929

Indiplon in the management of insomnia.

PubMed

Lemon, Michael D; Strain, Joe D; Hegg, Annie M; Farver, Debra K

2009-09-21

Indiplon is a novel pyrazolopyrimidine, nonbenzodiazepine gamma-aminobutyric acid (GABA) agonist studied for the treatment of insomnia. This article reviews the chemistry, pharmacology, clinical pharmacokinetics, drug interactions, clinical trials, safety, tolerability, contraindications, use in special populations, and dosing of indiplon. OVID, International Pharmaceutical Abstracts (IPA), and PubMed databases were searched (1966 to February 2009) for the keywords indiplon, NBI-34060, and insomnia. References of key articles were also reviewed to identify additional publications. Only English language articles were selected for review. Indiplon has been shown to have high affinity and selectivity for the GABAalpha(1) receptor subunit associated with sedation. In clinical studies, indiplon has demonstrated efficacy in improving latency to sleep onset, latency to persistent sleep, total sleep time, wake time after sleep onset, number of awakenings after sleep onset, and overall sleep quality when compared to placebo. Indiplon has a favorable safety profile with limited rebound insomnia and no tolerance. Neurocrine Biosciences, Incorporated received an Approvable Letter from the United States Food and Drug Administration in December 2007 for the indiplon IR 5 mg and 10 mg capsules based on meeting three additional requirements. At the time of this writing, indiplon remains unapproved.

Fault-Tolerant and Elastic Streaming MapReduce with Decentralized Coordination

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

Kumbhare, Alok; Frincu, Marc; Simmhan, Yogesh

2015-06-29

The MapReduce programming model, due to its simplicity and scalability, has become an essential tool for processing large data volumes in distributed environments. Recent Stream Processing Systems (SPS) extend this model to provide low-latency analysis of high-velocity continuous data streams. However, integrating MapReduce with streaming poses challenges: first, the runtime variations in data characteristics such as data-rates and key-distribution cause resource overload, that inturn leads to fluctuations in the Quality of the Service (QoS); and second, the stateful reducers, whose state depends on the complete tuple history, necessitates efficient fault-recovery mechanisms to maintain the desired QoS in the presence ofmore » resource failures. We propose an integrated streaming MapReduce architecture leveraging the concept of consistent hashing to support runtime elasticity along with locality-aware data and state replication to provide efficient load-balancing with low-overhead fault-tolerance and parallel fault-recovery from multiple simultaneous failures. Our evaluation on a private cloud shows up to 2:8 improvement in peak throughput compared to Apache Storm SPS, and a low recovery latency of 700 -1500 ms from multiple failures.« less

Interleukin-21 regulates expression of key Epstein-Barr virus oncoproteins, EBNA2 and LMP1, in infected human B cells

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

Konforte, Danijela; Department of Immunology, University of Toronto, Toronto, M5S 1A8; Simard, Nathalie

Epstein-Barr virus (EBV) persists for the life of the host by accessing the long-lived memory B cell pool. It has been proposed that EBV uses different combinations of viral proteins, known as latency types, to drive infected B cells to make the transition from resting B cells to memory cells. This process is normally antigen-driven. A major unresolved question is what factors coordinate expression of EBV latency proteins. We have recently described novel type III latency EBV{sup +} B cell lines (OCI-BCLs) that were induced to differentiate into late plasmablasts/early plasma cells in culture with interleukin-21 (IL-21), mimicking normal Bmore » cell development. The objective of this study was to determine whether IL-21-mediated signals also regulate the expression of key EBV latent proteins during this window of development. Here we show that IL-21-reduced gene and protein expression of growth-transforming EBV nuclear antigen 2 (EBNA2) in OCI-BCLs. By contrast, the expression of CD40-like, latent membrane protein 1 (LMP1) strongly increased in these cells suggesting an EBNA2-independent mode of regulation. Same results were also observed in Burkitt's lymphoma line Jijoye and B95-8 transformed lymphoblastoid cell lines. The effect of IL-21 on EBNA2 and LMP1 expression was attenuated by a pharmacological JAK inhibitor indicating involvement of JAK/STAT signalling in this process. Our study also shows that IL-21 induced transcription of ebna1 from the viral Q promoter (Qp)« less

Dynamic visual noise reduces confidence in short-term memory for visual information.

PubMed

Kemps, Eva; Andrade, Jackie

2012-05-01

Previous research has shown effects of the visual interference technique, dynamic visual noise (DVN), on visual imagery, but not on visual short-term memory, unless retention of precise visual detail is required. This study tested the prediction that DVN does also affect retention of gross visual information, specifically by reducing confidence. Participants performed a matrix pattern memory task with three retention interval interference conditions (DVN, static visual noise and no interference control) that varied from trial to trial. At recall, participants indicated whether or not they were sure of their responses. As in previous research, DVN did not impair recall accuracy or latency on the task, but it did reduce recall confidence relative to static visual noise and no interference. We conclude that DVN does distort visual representations in short-term memory, but standard coarse-grained recall measures are insensitive to these distortions.

Properties of the internal clock.

PubMed

Church, R M

1984-01-01

Evidence has been cited for the following properties of the parts of the psychological process used for timing intervals: The pacemaker has a mean rate that can be varied by drugs, diet, and stress. The switch has a latency to operate and it can be operated in various modes, such as run, stop, and reset. The accumulator times up, in absolute, arithmetic units. Working memory can be reset on command or, after lesions have been created in the fimbria fornix, when there is a gap in a signal. The transformation from the accumulator to reference memory is done with a multiplicative constant that is affected by drugs, lesions, and individual differences. The comparator uses a ratio between the value in the accumulator (or working memory) and reference memory. Finally, there must be multiple switch-accumulator modules to handle simultaneous temporal processing; and the psychological timing process may be used on some occasions and not on others.

Radiation-Tolerant Intelligent Memory Stack - RTIMS

NASA Technical Reports Server (NTRS)

Ng, Tak-kwong; Herath, Jeffrey A.

2011-01-01

This innovation provides reconfigurable circuitry and 2-Gb of error-corrected or 1-Gb of triple-redundant digital memory in a small package. RTIMS uses circuit stacking of heterogeneous components and radiation shielding technologies. A reprogrammable field-programmable gate array (FPGA), six synchronous dynamic random access memories, linear regulator, and the radiation mitigation circuits are stacked into a module of 42.7 42.7 13 mm. Triple module redundancy, current limiting, configuration scrubbing, and single- event function interrupt detection are employed to mitigate radiation effects. The novel self-scrubbing and single event functional interrupt (SEFI) detection allows a relatively soft FPGA to become radiation tolerant without external scrubbing and monitoring hardware

Effects of aging and involuntary capture of attention on event-related potentials associated with the processing of and the response to a target stimulus

PubMed Central

Cid-Fernández, Susana; Lindín, Mónica; Díaz, Fernando

2014-01-01

The main aim of the present study was to assess whether aging modulates the effects of involuntary capture of attention by novel stimuli on performance, and on event-related potentials (ERPs) associated with target processing (N2b and P3b) and subsequent response processes (stimulus-locked Lateralized Readiness Potential -sLRP- and response-locked Lateralized Readiness Potential -rLRP-). An auditory-visual distraction-attention task was performed by 77 healthy participants, divided into three age groups (Young: 21–29, Middle-aged: 51–64, Old: 65–84 years old). Participants were asked to attend to visual stimuli and to ignore auditory stimuli. Aging was associated with slowed reaction times, target stimulus processing in working memory (WM, longer N2b and P3b latencies) and selection and preparation of the motor response (longer sLRP and earlier rLRP onset latencies). In the novel relative to the standard condition we observed, in the three age groups: (1) a distraction effect, reflected in a slowing of reaction times, of stimuli categorization in WM (longer P3b latency), and of motor response selection (longer sLRP onset latency); (2) a facilitation effect on response preparation (later rLRP onset latency), and (3) an increase in arousal (larger amplitudes of all ERPs evaluated, except for N2b amplitude in the Old group). A distraction effect on the stimulus evaluation processes (longer N2b latency) were also observed, but only in middle-aged and old participants, indicating that the attentional capture slows the stimulus evaluation in WM from early ages (from 50 years onwards, without differences between middle-age and older adults), but not in young adults. PMID:25294999

Detection of herpes simplex virus type 2 (HSV-2) -specific cell-mediated immune responses in guinea pigs during latent HSV-2 genital infection.

PubMed

Perry, Clarice L; Banasik, Brianne N; Gorder, Summer R; Xia, Jingya; Auclair, Sarah; Bourne, Nigel; Milligan, Gregg N

2016-12-01

Genital infections with herpes simplex virus type 2 (HSV-2) are a source of considerable morbidity and are a health concern for newborns exposed to virus during vaginal delivery. Additionally, HSV-2 infection diminishes the integrity of the vaginal epithelium resulting in increased susceptibility of individuals to infection with other sexually transmitted pathogens. Understanding immune protection against HSV-2 primary infection and immune modulation of virus shedding events following reactivation of the virus from latency is important for the development of effective prophylactic and therapeutic vaccines. Although the murine model of HSV-2 infection is useful for understanding immunity following immunization, it is limited by the lack of spontaneous reactivation of HSV-2 from latency. Genital infection of guinea pigs with HSV-2 accurately models the disease of humans including the spontaneous reactivation of HSV-2 from latency and provides a unique opportunity to examine virus-host interactions during latency. Although the guinea pig represents an accurate model of many human infections, relatively few reagents are available to study the immunological response to infection. To analyze the cell-mediated immune response of guinea pigs at extended periods of time after establishment of HSV-2 latency, we have modified flow-cytometry based proliferation assays and IFN-γ ELISPOT assays to detect and quantify HSV-specific cell-mediated responses during latent infection of guinea pigs. Here we demonstrate that a combination of proliferation and ELISPOT assays can be used to quantify and characterize effecter function of virus-specific immune memory responses during HSV-latency. Copyright © 2016 Elsevier B.V. All rights reserved.

Results from On-Orbit Testing of the Fram Memory Test Experiment on the Fastsat Micro-Satellite

NASA Technical Reports Server (NTRS)

MacLeod, Todd C.; Sims, W. Herb; Varnavas, Kosta A.; Ho, Fat D.

2011-01-01

NASA is planning on going beyond Low Earth orbit with manned exploration missions. The radiation environment for most Low Earth orbit missions is harsher than at the Earth's surface but much less harsh than deep space. Development of new electronics is needed to meet the requirements of high performance, radiation tolerance, and reliability. The need for both Volatile and Non-volatile memory has been identified. Emerging Non-volatile memory technologies (FRAM, C-RAM,M-RAM, R-RAM, Radiation Tolerant FLASH, SONOS, etc.) need to be investigated for use in Space missions. An opportunity arose to fly a small memory experiment on a high inclination satellite (FASTSAT). An off-the-shelf 512K Ramtron FRAM was chosen to be tested in the experiment.

History of concussion impacts electrophysiological correlates of working memory.

PubMed

Hudac, Caitlin M; Cortesa, Cathryn S; Ledwidge, Patrick S; Molfese, Dennis L

2017-10-10

Sports-related concussions occur in approximately 21% of college athletes with implications for long-term cognitive impairments in working memory. Working memory involves the capacity to maintain short-term information and integrate with higher-order cognitive processing for planning and behavior execution, critical skills for optimal cognitive and athletic performance. This study quantified working memory impairments in 36 American football college athletes (18-23years old) using event-related potentials (ERPs). Despite performing similarly in a standard 2-back working memory task, athletes with history of concussion exhibited larger P1 and P3 amplitudes compared to Controls. Concussion History group latencies were slower for the P1 and faster for the N2. Source estimation analyses indicated that previously concussed athletes engaged different brain regions compared to athletes with no concussion history. These findings suggest that ERPs may be a sensitive and objective measure to detect long-term cognitive consequences of concussion. Copyright © 2017 Elsevier B.V. All rights reserved.

GPU-Accelerated Forward and Back-Projections with Spatially Varying Kernels for 3D DIRECT TOF PET Reconstruction.

PubMed

Ha, S; Matej, S; Ispiryan, M; Mueller, K

2013-02-01

We describe a GPU-accelerated framework that efficiently models spatially (shift) variant system response kernels and performs forward- and back-projection operations with these kernels for the DIRECT (Direct Image Reconstruction for TOF) iterative reconstruction approach. Inherent challenges arise from the poor memory cache performance at non-axis aligned TOF directions. Focusing on the GPU memory access patterns, we utilize different kinds of GPU memory according to these patterns in order to maximize the memory cache performance. We also exploit the GPU instruction-level parallelism to efficiently hide long latencies from the memory operations. Our experiments indicate that our GPU implementation of the projection operators has slightly faster or approximately comparable time performance than FFT-based approaches using state-of-the-art FFTW routines. However, most importantly, our GPU framework can also efficiently handle any generic system response kernels, such as spatially symmetric and shift-variant as well as spatially asymmetric and shift-variant, both of which an FFT-based approach cannot cope with.

GPU-Accelerated Forward and Back-Projections With Spatially Varying Kernels for 3D DIRECT TOF PET Reconstruction

NASA Astrophysics Data System (ADS)

Ha, S.; Matej, S.; Ispiryan, M.; Mueller, K.

2013-02-01

We describe a GPU-accelerated framework that efficiently models spatially (shift) variant system response kernels and performs forward- and back-projection operations with these kernels for the DIRECT (Direct Image Reconstruction for TOF) iterative reconstruction approach. Inherent challenges arise from the poor memory cache performance at non-axis aligned TOF directions. Focusing on the GPU memory access patterns, we utilize different kinds of GPU memory according to these patterns in order to maximize the memory cache performance. We also exploit the GPU instruction-level parallelism to efficiently hide long latencies from the memory operations. Our experiments indicate that our GPU implementation of the projection operators has slightly faster or approximately comparable time performance than FFT-based approaches using state-of-the-art FFTW routines. However, most importantly, our GPU framework can also efficiently handle any generic system response kernels, such as spatially symmetric and shift-variant as well as spatially asymmetric and shift-variant, both of which an FFT-based approach cannot cope with.

Intrathecal Huperzine A Increases Thermal Escape Latency and Decreases Flinching Behavior in the Formalin Test in Rats

PubMed Central

Park, Paula; Schachter, Steven; Yaksh, Tony

2010-01-01

Huperzine A (HupA) is an alkaloid isolated from the Chinese club moss Huperzia serrata and has been used for improving memory, cognitive and behavioral function in patients with Alzheimer's disease in China. It has NMDA antagonist and anticholinesterase activity and has shown anticonvulsant and antinociceptive effects in preliminary studies when administered intraperitoneally to mice. To better characterize the antinociceptive effects of HupA at the spinal level, Holtzman rats were implanted with intrathecal catheters to measure thermal escape latency using Hargreaves thermal escape testing system and flinching behavior using the formalin test. Intrathecal (IT) administration of HupA showed a dose-dependent increase in thermal escape latency with an ED50 of 0.57 μg. Atropine reversed the increase in thermal escape latency produced by 10 μg HupA, indicating an antinociceptive mechanism through muscarinic cholinergic receptors. The formalin test showed that HupA decreased flinching behavior in a dose-dependent manner. Atropine also reversed the decrease in flinching behavior caused by 10 μg HupA. A dose-dependent increase of side effects including scratching, biting, and chewing tails was observed, although antinociceptive effects were observed in doses that did not produce any adverse effects. PMID:20026382

Intrathecal huperzine A increases thermal escape latency and decreases flinching behavior in the formalin test in rats.

PubMed

Park, Paula; Schachter, Steven; Yaksh, Tony

2010-02-05

Huperzine A (HupA) is an alkaloid isolated from the Chinese club moss Huperzia serrata and has been used for improving memory, cognitive and behavioral function in patients with Alzheimer's disease in China. It has NMDA antagonist and anticholinesterase activity and has shown anticonvulsant and antinociceptive effects in preliminary studies when administered intraperitoneally to mice. To better characterize the antinociceptive effects of HupA at the spinal level, Holtzman rats were implanted with intrathecal catheters to measure thermal escape latency using Hargreaves thermal escape testing system and flinching behavior using the formalin test. Intrathecal (IT) administration of HupA showed a dose-dependent increase in thermal escape latency with an ED50 of 0.57 microg. Atropine reversed the increase in thermal escape latency produced by 10 microg HupA, indicating an antinociceptive mechanism through muscarinic cholinergic receptors. The formalin test showed that HupA decreased flinching behavior in a dose-dependent manner. Atropine also reversed the decrease in flinching behavior caused by 10 microg HupA. A dose-dependent increase of side effects including scratching, biting, and chewing tails was observed, although antinociceptive effects were observed in doses that did not produce any adverse effects. (c) 2009 Elsevier Ireland Ltd. All rights reserved.

Music training and working memory: an ERP study.

PubMed

George, Elyse M; Coch, Donna

2011-04-01

While previous research has suggested that music training is associated with improvements in various cognitive and linguistic skills, the mechanisms mediating or underlying these associations are mostly unknown. Here, we addressed the hypothesis that previous music training is related to improved working memory. Using event-related potentials (ERPs) and a standardized test of working memory, we investigated both neural and behavioral aspects of working memory in college-aged, non-professional musicians and non-musicians. Behaviorally, musicians outperformed non-musicians on standardized subtests of visual, phonological, and executive memory. ERPs were recorded in standard auditory and visual oddball paradigms (participants responded to infrequent deviant stimuli embedded in lists of standard stimuli). Electrophysiologically, musicians demonstrated faster updating of working memory (shorter latency P300s) in both the auditory and visual domains and musicians allocated more neural resources to auditory stimuli (larger amplitude P300), showing increased sensitivity to the auditory standard/deviant difference and less effortful updating of auditory working memory. These findings demonstrate that long-term music training is related to improvements in working memory, in both the auditory and visual domains and in terms of both behavioral and ERP measures. Copyright © 2011 Elsevier Ltd. All rights reserved.

A New Local Bipolar Autoassociative Memory Based on External Inputs of Discrete Recurrent Neural Networks With Time Delay.

PubMed

Zhou, Caigen; Zeng, Xiaoqin; Luo, Chaomin; Zhang, Huaguang

In this paper, local bipolar auto-associative memories are presented based on discrete recurrent neural networks with a class of gain type activation function. The weight parameters of neural networks are acquired by a set of inequalities without the learning procedure. The global exponential stability criteria are established to ensure the accuracy of the restored patterns by considering time delays and external inputs. The proposed methodology is capable of effectively overcoming spurious memory patterns and achieving memory capacity. The effectiveness, robustness, and fault-tolerant capability are validated by simulated experiments.In this paper, local bipolar auto-associative memories are presented based on discrete recurrent neural networks with a class of gain type activation function. The weight parameters of neural networks are acquired by a set of inequalities without the learning procedure. The global exponential stability criteria are established to ensure the accuracy of the restored patterns by considering time delays and external inputs. The proposed methodology is capable of effectively overcoming spurious memory patterns and achieving memory capacity. The effectiveness, robustness, and fault-tolerant capability are validated by simulated experiments.

Effects of levothyroxine on learning and memory deficits in a rat model of Alzheimer's disease: the role of BDNF and oxidative stress.

PubMed

Bavarsad, Kowsar; Hadjzadeh, Mousa-Al-Reza; Hosseini, Mahmoud; Pakdel, Roghayeh; Beheshti, Farimah; Bafadam, Soleyman; Ashaari, Zeinab

2018-06-21

The effect of levothyroxine (L-T4) on the learning and memory impairment induced by streptozotocin (STZ) and brain tissue oxidative damage in rats was evaluated. An animal model of the Alzheimer's disease (AD) was established by intracerebroventricular injection of STZ (3 mg/kg) in male Wistar rats (250 ± 50 g). After that, the rats were treated for 3 weeks with L-T4 (10, 100 μg/kg) or normal saline. Passive avoidance (PA) learning and spatial memory were evaluated using shuttle box and Morris water maze (MWM), respectively. Finally, the rats were euthanized, their blood samples were collected for further thyroxine assessment and their brains were removed after decapitation in order to measure the oxidative stress parameters and brain-derived neurotrophic factor (BDNF). In the MWM, latency (s) increased in the AD rats compared with the normal control group while it decreased in the 10 μg/kg L-T4 injected AD rats compared with the AD group. In the PA, the latency for entering the dark compartment was lower in the AD group than in the normal control group and it decreased in the 10 μg/kg L-T4 injected AD rats. The low dose of L-T4 (10 μg/kg) reduced malondialdehyde concentration but increased thiols concentration, superoxide dismutase, catalase activities and BDNF level in hippocampal tissues of the AD rats. Injection of L-T4 (10 μg/kg) alleviated memory deficits and also improved factors of oxidative stress and BDNF level in the STZ-induced AD rats.

Pharmacodynamic and pharmacokinetic effects of MK-0343, a GABA(A) alpha2,3 subtype selective agonist, compared to lorazepam and placebo in healthy male volunteers.

PubMed

de Haas, S L; de Visser, S J; van der Post, J P; Schoemaker, R C; van Dyck, K; Murphy, M G; de Smet, M; Vessey, L K; Ramakrishnan, R; Xue, L; Cohen, A F; van Gerven, J M A

2008-01-01

The use of non-selective gamma-aminobutyric acid (GABA) enhancers, such as benzodiazepines in the treatment of anxiety disorders is still widespread but hampered by unfavourable side effects. some of these may be associated with binding properties to certain subtypes of the GABA(A) receptor that are unnecessary for therapeutic effects. MK-0343 was designed to be a less sedating anxiolytic, based on reduced efficacy at the alpha1 subtype and significant efficacy at alpha2 and alpha3 subtypes of the GABA(A) receptor. This paper is a double-blind, four-way cross-over (n = 12) study to investigate the effects of MK-0343 (0.25 and 0.75 mg) in comparison to placebo and an anxiolytic dose (2 mg) of the non-selective agonist lorazepam. Effects were measured by eye movements, body sway, Visual Analogue scales (VAS) and memory tests. Lorazepam impaired saccadic peak velocity (SPV), VAs alertness scores, postural stability and memory and increased saccadic latency and inaccuracy. MK-0343 0.75 mg was equipotent with lorazepam as indicated by SPV (-42.4 deg/s), saccadic latency (0.02 s) and VAS alertness scores (1.50 ln mm), while effects on memory and postural stability were smaller. MK-0343 0.25 mg only affected postural stability to a similar extent as MK-0343 0.75 mg. The effect profile of MK-0343 0.75 mg is different from the full agonist lorazepam, which could reflect the selective actions of this compound. Although less effect on VAS alertness was expected, diminished effects on memory and postural stability were present. Clinical studies in anxiety patients should show whether this dose of MK-0343 is therapeutically effective with a different side-effect profile.

Retrieval of bilingual autobiographical memories: effects of cue language and cue imageability.

PubMed

Mortensen, Linda; Berntsen, Dorthe; Bohn, Ocke-Schwen

2015-01-01

An important issue in theories of bilingual autobiographical memory is whether linguistically encoded memories are represented in language-specific stores or in a common language-independent store. Previous research has found that autobiographical memory retrieval is facilitated when the language of the cue is the same as the language of encoding, consistent with language-specific memory stores. The present study examined whether this language congruency effect is influenced by cue imageability. Danish-English bilinguals retrieved autobiographical memories in response to Danish and English high- or low-imageability cues. Retrieval latencies were shorter to Danish than English cues and shorter to high- than low-imageability cues. Importantly, the cue language effect was stronger for low-than high-imageability cues. To examine the relationship between cue language and the language of internal retrieval, participants identified the language in which the memories were internally retrieved. More memories were retrieved when the cue language was the same as the internal language than when the cue was in the other language, and more memories were identified as being internally retrieved in Danish than English, regardless of the cue language. These results provide further evidence for language congruency effects in bilingual memory and suggest that this effect is influenced by cue imageability.

How Is the Serial Order of a Visual Sequence Represented? Insights from Transposition Latencies

ERIC Educational Resources Information Center

Hurlstone, Mark J.; Hitch, Graham J.

2018-01-01

A central goal of research on short-term memory (STM) over the past 2 decades has been to identify the mechanisms that underpin the representation of serial order, and to establish whether these mechanisms are the same across different modalities and domains (e.g., verbal, visual, spatial). A fruitful approach to addressing this question has…

Lack of Set Size Effects in Spatial Updating: Evidence for Offline Updating

ERIC Educational Resources Information Center

Hodgson, Eric; Waller, David

2006-01-01

Four experiments required participants to keep track of the locations of (i.e., update) 1, 2, 3, 4, 6, 8, 10, or 15 target objects after rotating. Across all conditions, updating was unaffected by set size. Although some traditional set size effects (i.e., a linear increase of latency with memory load) were observed under some conditions, these…

Age-Related Changes in Antisaccade Task Performance: Inhibitory Control or Working-Memory Engagement?

ERIC Educational Resources Information Center

Eenshuistra, R.M.; Ridderinkhof, K.R.; Molen, M.W.v.d.

2004-01-01

In antisaccade tasks, subjects are required to generate a saccade in the direction opposite to the location of a sudden-onset target stimulus. Compared to young adults, older adults tend to make more reflex-like eye movements towards the target, and/or show longer saccadic onset latencies on correct direct antisaccades. To better understand the…

L1 track trigger for the CMS HL-LHC upgrade using AM chips and FPGAs

NASA Astrophysics Data System (ADS)

Fedi, Giacomo

2017-08-01

The increase of luminosity at the HL-LHC will require the introduction of tracker information in CMS's Level-1 trigger system to maintain an acceptable trigger rate when selecting interesting events, despite the order of magnitude increase in minimum bias interactions. To meet the latency requirements, dedicated hardware has to be used. This paper presents the results of tests of a prototype system (pattern recognition ezzanine) as core of pattern recognition and track fitting for the CMS experiment, combining the power of both associative memory custom ASICs and modern Field Programmable Gate Array (FPGA) devices. The mezzanine uses the latest available associative memory devices (AM06) and the most modern Xilinx Ultrascale FPGAs. The results of the test for a complete tower comprising about 0.5 million patterns is presented, using as simulated input events traversing the upgraded CMS detector. The paper shows the performance of the pattern matching, track finding and track fitting, along with the latency and processing time needed. The pT resolution over pT of the muons measured using the reconstruction algorithm is at the order of 1% in the range 3-100 GeV/c.

Conceptual design and feasibility evaluation model of a 10 to the 8th power bit oligatomic mass memory. Volume 1: Conceptual design

NASA Technical Reports Server (NTRS)

Recksiedler, A. L.; Lutes, C. L.

1972-01-01

The oligatomic (mirror) thin film memory technology is a suitable candidate for general purpose spaceborne applications in the post-1975 time frame. Capacities of around 10 to the 8th power bits can be reliably implemented with systems designed around a 335 million bit module. The recommended mode was determined following an investigation of implementation sizes ranging from an 8,000,000 to 100,000,000 bits per module. Cost, power, weight, volume, reliability, maintainability and speed were investigated. The memory includes random access, NDRO, SEC-DED, nonvolatility, and dual interface characteristics. The applications most suitable for the technology are those involving a large capacity with high speed (no latency), nonvolatility, and random accessing.

Huperzine A attenuates cognitive deficits and hippocampal neuronal damage after transient global ischemia in gerbils.

PubMed

Zhou, J; Zhang, H Y; Tang, X C

2001-11-09

The protective effects of huperzine A on transient global ischemia in gerbils were investigated. Five min of global ischemia in gerbils results in working memory impairments shown by increased escape latency in a water maze and reduced time spent in the target quadrant. These signs of dysfunction are accompanied by delayed degeneration of pyramidal hippocampal CA1 neurons and by decrease in acetylcholinesterase activity in the hippocampus. Subchronic oral administration of huperzine A (0.1 mg/kg, twice per day for 14 days) after ischemia significantly reduced the memory impairment, reduced neuronal degeneration in the CA1 region, and partially restored hippocampal choline acetyltransferase activity. The ability of huperzine A to attenuate memory deficits and neuronal damage after ischemia might be beneficial in cerebrovascular type dementia.

DESTINY

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

2015-03-10

DESTINY is a comprehensive tool for modeling 3D and 2D cache designs using SRAM,embedded DRAM (eDRAM), spin transfer torque RAM (STT-RAM), resistive RAM (ReRAM), and phase change RAM (PCN). In its purpose, it is similar to CACTI, CACTI-3DD or NVSim. DESTINY is very useful for performing design-space exploration across several dimensions, such as optimizing for a target (e.g. latency, area or energy-delay product) for agiven memory technology, choosing the suitable memory technology or fabrication method (i.e. 2D v/s 3D) for a given optimization target, etc. DESTINY has been validated against several cache prototypes. DESTINY is expected to boost studies ofmore » next-generation memory architectures used in systems ranging from mobile devices to extreme-scale supercomputers.« less

Bisphenol-A rapidly enhanced passive avoidance memory and phosphorylation of NMDA receptor subunits in hippocampus of young rats

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

Xu Xiaohong, E-mail: xuxh63@zjnu.cn; Li Tao; Luo Qingqing

Bisphenol-A (BPA), an endocrine disruptor, is found to influence development of brain and behaviors in rodents. The previous study indicated that perinatal exposure to BPA impaired learning-memory and inhibited N-methyl-D-aspartate receptor (NMDAR) subunits expressions in hippocampus during the postnatal development in rats; and in cultured hippocampal neurons, BPA rapidly promotes dynamic changes in dendritic morphology through estrogen receptor-mediated pathway by concomitant phosphorylation of NMDAR subunit NR2B. In the present study, we examined the rapid effect of BPA on passive avoidance memory and NMDAR in the developing hippocampus of Sprague-Dawley rats at the age of postnatal day 18. The results showedmore » that BPA or estradiol benzoate (EB) rapidly extended the latency to step down from the platform 1 h after footshock and increased the phosphorylation levels of NR1, NR2B, and mitogen-activated extracellular signal-regulated kinase (ERK) in hippocampus within 1 h. While 24 h after BPA or EB treatment, the improved memory and the increased phosphorylation levels of NR1, NR2B, ERK disappeared. Furthermore, pre-treatment with an estrogen receptors (ERs) antagonist, ICI182,780, or an ERK-activating kinase inhibitor, U0126, significantly attenuated EB- or BPA-induced phosphorylations of NR1, NR2B, and ERK within 1 h. These data suggest that BPA rapidly enhanced short-term passive avoidance memory in the developing rats. A non-genomic effect via ERs may mediate the modulation of the phosphorylation of NMDAR subunits NR1 and NR2B through ERK signaling pathway. - Highlights: > BPA rapidly extended the latency to step down from platform 1 h after footshock. > BPA rapidly increased pNR1, pNR2B, and pERK in hippocampus within 1 h. > ERs antagonist or MEK inhibitor attenuated BPA-induced pNR1, pNR2B, and pERK.« less

Administration of nicotinic receptor antagonists during the period of memory consolidation affects passive avoidance learning and modulates synaptic efficiency in the CA1 region in vivo.

PubMed

Dobryakova, Y V; Gurskaya, O Ya; Markevich, V A

2015-01-22

We examined whether a non-selective antagonist of nAChRs mecamylamine and selective antagonists of α4β2-containing nAChRs dihydro-β-erythroidine (DHβE) and α7-containing nAChRs methyllycaconitine (MLA) affect learning performance and synaptic efficiency in the CA1 area of the hippocampus of freely moving rats during the memory consolidation period. Adult male Wistar rats received mecamylamine (0.5 mg/kg), DHβE (1 mg/kg), MLA (2 mg/kg) or saline immediately after training in a passive avoidance task. Memory retention was examined 24 h after the training. The changes in the latency of the first entry into a dark compartment of a test chamber were chosen as a criterion of learning. The ability of nAChRs antagonists to induce changes in the basal level of focal potentials (fEPSP, field excitatory postsynaptic potential) was estimated before training (baseline), 90 min after the training (consolidation period) and 24 h after the training (retention period). We found that in untrained rats mecamylamine, DHβE and MLA diminished the amplitude of fEPSP within the first 90 min after the injection; similar effect was observed in DHβE- and MLA-treated trained animals. These suppressive effects of DHβE and MLA were associated with memory loss. In contrast, mecamylamine, when applied to trained animals, tended to increase latency to enter the dark chamber and did not influence fEPSP during first 90 min after injection. Thus, the nAChRs antagonists with different selectivity induced different changes in fEPSP and behavior which suggests that nAChRs with different subunit composition are diversely involved in memory consolidation. Copyright © 2014 IBRO. Published by Elsevier Ltd. All rights reserved.

Effect of food azo dye tartrazine on learning and memory functions in mice and rats, and the possible mechanisms involved.

PubMed

Gao, Yonglin; Li, Chunmei; Shen, Jingyu; Yin, Huaxian; An, Xiulin; Jin, Haizhu

2011-08-01

Tartrazine is an artificial azo dye commonly used in human food and pharmaceutical products. The present study was conducted to evaluate the toxic effect of tartrazine on the learning and memory functions in mice and rats. Animals were administered different doses of tartrazine for a period of 30 d and were evaluated by open-field test, step-through test, and Morris water maze test, respectively. Furthermore, the biomarkers of the oxidative stress and pathohistology were also measured to explore the possible mechanisms involved. The results indicated that tartrazine extract significantly enhanced active behavioral response to the open field, increased the escape latency in Morris water maze test and decreased the retention latency in step-through tests. The decline in the activities of catalase, glutathione peroxidase (GSH-Px), and superoxide dismutase (SOD) as well as a rise in the level of malonaldehyde (MDA) were observed in the brain of tartrazine-treated rats, and these changes were associated with the brain from oxidative damage. The dose levels of tartrazine in the present study produced a few adverse effects in learning and memory functions in animals. The mechanisms might be attributed to promoting lipid peroxidation products and reactive oxygen species, inhibiting endogenous antioxidant defense enzymes and the brain tissue damage. Tartrazine is an artificial azo dye commonly used in human food and pharmaceutical products. Since the last assessment carried out by the Joint FAO/WHO Expert Committee on Food Additives in 1964, many new studies have been conducted. However, there is a little information about the effects on learning and memory performance. The present study was conducted to evaluate the toxic effect of tartrazine on the learning and memory functions in animals and its possible mechanism involved. Based on our results, we believe that more extensive assessment of food additives in current use is warranted. © 2011 Institute of Food Technologists®

The reduced serum free triiodothyronine and increased dorsal hippocampal SNAP-25 and Munc18-1 had existed in middle-aged CD-1 mice with mild spatial cognitive impairment.

PubMed

Cao, Lei; Jiang, Wei; Wang, Fang; Yang, Qi-Gang; Wang, Chao; Chen, Yong-Ping; Chen, Gui-Hai

2013-12-02

Changes of synaptic proteins in highlighted brain regions and decreased serum thyroid hormones (THs) have been implied in age-related learning and memory decline. Previously, we showed significant pairwise correlations among markedly impaired spatial learning and memory ability, decreased serum free triiodothyronine (FT3) and increased hippocampal SNAP-25 and Munc18-1 in old Kunming mice. However, whether these changes and the correlations occur in middle-age mice remains unclear. Since this age is one of the best stages to study age-related cognitive decline, we explored the spatial learning and memory ability, serum THs, cerebral SNAP-25 and Munc18-1 levels and their relationships of middle-aged mice in this study. The learning and memory abilities of 35 CD-1 mice (19 mice aged 6 months and 16 mice aged 12 months) were measured with a radial six-arm water maze (RAWM). The SNAP-25 and Munc18-1 levels were semi-quantified by Western blotting and the serum THs were detected by radioimmunoassay. The results showed the middle-aged mice had decreased serum FT3, increased dorsal hippocampal (DH) SNAP-25 and Munc18-1, and many or long number of errors and latency in both learning and memory phases of the RAWM. The Pearson's correlation test showed that the DH SANP-25 and Munc18-1 levels were positively correlated with the number of errors and latency in learning phases of the RAWM. Meanwhile, the DH SANP-25 and Munc18-1 levels negatively correlated with the serum FT3 level. These results suggested that reduced FT3 with increased DH SNAP-25 and Munc18-1 levels might be involved in the spatial learning ability decline in the middle-aged mice. © 2013 Elsevier B.V. All rights reserved.

Differentiation of Forebrain and Hippocampal Dopamine 1-Class Receptors, D1R and D5R, in Spatial Learning and Memory

PubMed Central

Sariñana, Joshua; Tonegawa, Susumu

2017-01-01

Activation of prefrontal cortical (PFC), striatal, and hippocampal dopamine 1-class receptors (D1R and D5R) is necessary for normal spatial information processing. Yet the precise role of the D1R versus the D5R in the aforementioned structures, and their specific contribution to the water-maze spatial learning task remains unknown. D1R- and D5R- specific in situ hybridization probes showed that forebrain restricted D1R and D5R KO mice (F-D1R/D5R KO) displayed D1R mRNA deletion in the medial (m)PFC, dorsal and ventral striatum, and the dentate gyrus (DG) of the hippocampus. D5R mRNA deletion was limited to the mPFC, the CA1 and DG hippocampal subregions. F-D1R/D5R KO mice were given water-maze training and displayed subtle spatial latency differences between genotypes and spatial memory deficits during both regular and reversal training. To differentiate forebrain D1R from D5R activation, forebrain restricted D1R KO (F-D1R KO) and D5R KO (F-D5R KO) mice were trained on the water-maze task. F-D1R KO animals exhibited escape latency deficits throughout regular and reversal training as well as spatial memory deficits during reversal training. F-D1R KO mice also showed perseverative behavior during the reversal spatial memory probe test. In contrast, F-D5R KO animals did not present observable deficits on the water-maze task. Because F-D1R KO mice showed water-maze deficits we tested the necessity of hippocampal D1R activation for spatial learning and memory. We trained DG restricted D1R KO (DG-D1R KO) mice on the water-maze task. DG-D1R KO mice did not present detectable spatial memory deficit, but did show subtle deficits during specific days of training. Our data provides evidence that forebrain D5R activation plays a unique role in spatial learning and memory in conjunction with D1R activation. Moreover, these data suggest that mPFC and striatal, but not DG D1R activation are essential for spatial learning and memory. PMID:26174222

The effects of vitamin E on brain derived neurotrophic factor, tissues oxidative damage and learning and memory of juvenile hypothyroid rats.

PubMed

Baghcheghi, Yousef; Beheshti, Farimah; Shafei, Mohammad Naser; Salmani, Hossein; Sadeghnia, Hamid Reza; Soukhtanloo, Mohammad; Anaeigoudari, Akbar; Hosseini, Mahmoud

2018-06-01

The effects of vitamin E (Vit E) on brain derived neurotrophic factor (BDNF) and brain tissues oxidative damage as well as on learning and memory impairments in juvenile hypothyroid rats were examined. The rats were grouped as: (1) Control; (2) Propylthiouracil (PTU); (3) PTU-Vit E and (4) Vit E. PTU was added to their drinking water (0.05%) during 6 weeks. Vit E (20 mg/kg) was daily injected (IP). Morris water maze (MWM) and passive avoidance (PA) were carried out. The animals were deeply anesthetized and the brain tissues were removed for biochemical measurements. PTU increased the escape latency and traveled path in MWM (P < 0.001). It also shortened the latency to enter the dark compartment of PA as well as the time spent in the target quadrant in probe trial of MWM (P < 0.01-P < 0.001). All the effects of PTU were reversed by Vit E (P < 0.01-P < 0.001). PTU administration attenuated thiol and BDNF content as well as the activities of superoxide dismutase (SOD) and catalase (CAT) in the brain tissues while increased molondialdehyde (MDA). Moreover, Vit E improved BDNF, thiol, SOD and CAT while diminished MDA. The results of the present study showed that Vit E improved BDNF and prevented from brain tissues oxidative damage as well as learning and memory impairments in juvenile hypothyroid rats.

Cognitive effects of methylphenidate and levodopa in healthy volunteers.

PubMed

Linssen, A M W; Sambeth, A; Vuurman, E F P M; Riedel, W J

2014-02-01

Our previous study showed enhanced declarative memory consolidation after acute methylphenidate (MPH) administration. The primary aim of the current study was to investigate the duration of this effect. Secondary, the dopaminergic contribution of MPH effects, the electrophysiological correlates of declarative memory, and the specificity of memory enhancing effects of MPH to declarative memory were assessed. Effects of 40 mg of MPH on memory performance were compared to 100mg of levodopa (LEV) in a placebo-controlled crossover study with 30 healthy volunteers. Memory performance testing included a word learning test, the Sternberg memory scanning task, a paired associates learning task, and a spatial working memory task. During the word learning test, event-related brain potentials (ERPs) were measured. MPH failed to enhance retention of words at a 30 min delay, but it improved 24 h delayed memory recall relative to PLA and LEV. Furthermore, during encoding, the P3b and P600 ERP latencies were prolonged and the P600 amplitude was larger after LEV compared to PLA and MPH. MPH speeded response times on the Sternberg Memory Scanning task and improved performance on the Paired Associates Learning task, relative to LEV, but not PLA. Performance on the Spatial working memory task was not affected by the treatments. These findings suggest that MPH and LEV might have opposite effects on memory. © 2013 Published by Elsevier B.V. and ECNP.

Performance of defect-tolerant set-associative cache memories

NASA Technical Reports Server (NTRS)

Frenzel, J. F.

1991-01-01

The increased use of on-chip cache memories has led researchers to investigate their performance in the presence of manufacturing defects. Several techniques for yield improvement are discussed and results are presented which indicate that set-associativity may be used to provide defect tolerance as well as improve the cache performance. Tradeoffs between several cache organizations and replacement strategies are investigated and it is shown that token-based replacement may be a suitable alternative to the widely-used LRU strategy.

[Semantic interference and pathological anxiety: experimental approach in generalized anxiety].

PubMed

Azaïs, F; Granger, B; Debray, Q

1994-01-01

Patients with D.S.M. III-R generalized anxiety disorder and normal controls performed a computerized Stroop color naming-task in which they named colors of threat-related, positive and neutral words. Compared to controls, generalized anxious patients revealed a longer response latency for threat-related words, without correlation with anxious measures on Spielberger State-Trait Anxiety Inventory. In normal control group, response delay to emotional words was correlated to anxious score on STAI-Trait. There was no difference between the two groups in a recognition memory task. The results suggest existence of different semantic interference in categorical and normal anxiety, without implication of explicit memory.

Efficient implementation of a 3-dimensional ADI method on the iPSC/860

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

Van der Wijngaart, R.F.

1993-12-31

A comparison is made between several domain decomposition strategies for the solution of three-dimensional partial differential equations on a MIMD distributed memory parallel computer. The grids used are structured, and the numerical algorithm is ADI. Important implementation issues regarding load balancing, storage requirements, network latency, and overlap of computations and communications are discussed. Results of the solution of the three-dimensional heat equation on the Intel iPSC/860 are presented for the three most viable methods. It is found that the Bruno-Cappello decomposition delivers optimal computational speed through an almost complete elimination of processor idle time, while providing good memory efficiency.

Livermore Big Artificial Neural Network Toolkit

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

Essen, Brian Van; Jacobs, Sam; Kim, Hyojin

2016-07-01

LBANN is a toolkit that is designed to train artificial neural networks efficiently on high performance computing architectures. It is optimized to take advantages of key High Performance Computing features to accelerate neural network training. Specifically it is optimized for low-latency, high bandwidth interconnects, node-local NVRAM, node-local GPU accelerators, and high bandwidth parallel file systems. It is built on top of the open source Elemental distributed-memory dense and spars-direct linear algebra and optimization library that is released under the BSD license. The algorithms contained within LBANN are drawn from the academic literature and implemented to work within a distributed-memory framework.

The Tat Inhibitor Didehydro-Cortistatin A Prevents HIV-1 Reactivation from Latency

PubMed Central

Mousseau, Guillaume; Kessing, Cari F.; Fromentin, Rémi; Trautmann, Lydie; Chomont, Nicolas

2015-01-01

ABSTRACT Antiretroviral therapy (ART) inhibits HIV-1 replication, but the virus persists in latently infected resting memory CD4+ T cells susceptible to viral reactivation. The virus-encoded early gene product Tat activates transcription of the viral genome and promotes exponential viral production. Here we show that the Tat inhibitor didehydro-cortistatin A (dCA), unlike other antiretrovirals, reduces residual levels of viral transcription in several models of HIV latency, breaks the Tat-mediated transcriptional feedback loop, and establishes a nearly permanent state of latency, which greatly diminishes the capacity for virus reactivation. Importantly, treatment with dCA induces inactivation of viral transcription even after its removal, suggesting that the HIV promoter is epigenetically repressed. Critically, dCA inhibits viral reactivation upon CD3/CD28 or prostratin stimulation of latently infected CD4+ T cells from HIV-infected subjects receiving suppressive ART. Our results suggest that inclusion of a Tat inhibitor in current ART regimens may contribute to a functional HIV-1 cure by reducing low-level viremia and preventing viral reactivation from latent reservoirs. PMID:26152583

Study of cognitive functions in newly diagnosed cases of subclinical and clinical hypothyroidism.

PubMed

Sharma, Kirti; Behera, Joshil Kumar; Sood, Sushma; Rajput, Rajesh; Satpal; Praveen, Prashant

2014-01-01

Hypothyroidism is associated with significant neurocognitive deficits because hypothyroidism prevents the brain from adequately sustaining the energy consuming processes needed for neurotransmission, memory, and other higher brain functions. Hence, the study was done to assess the cognitive functions of newly diagnosed subclinical and clinical hypothyroid patients by evoked response potential P300. 75 patients each of newly diagnosed subclinical and clinical hypothyroid patients attending endocrinology clinic and 75 healthy age and sex matched euthyroid controls were considered for the study. P300 was recorded with Record Medicare System Polyrite, Chandigarh using auditory "oddball paradigm". The data was analyzed using ANOVA followed by post Tukey's test. Newly diagnosed clinical hypothyroid patients showed a significant increase in P300 latency compared to control (P < 0.05) and subclinical cases (P < 0.01) while there was no significant difference between the P300 latency of subclinical cases and control group. Also, there was no significant difference in P300 amplitude among the three groups. P300 latency in case of newly diagnosed hypothyroid clinical cases is significantly increased compared to newly diagnosed subclinical cases and control.

Taxing Working Memory during Retrieval of Emotional Memories Does Not Reduce Memory Accessibility When Cued with Reminders

PubMed Central

van Schie, Kevin; Engelhard, Iris M.; van den Hout, Marcel A.

2015-01-01

Earlier studies have shown that when individuals recall an emotional memory while simultaneously doing a demanding dual-task [e.g., playing Tetris, mental arithmetic, making eye movements (EM)], this reduces self-reported vividness and emotionality of the memory. These effects have been found up to 1 week later, but have largely been confined to self-report ratings. This study examined whether this dual-tasking intervention reduces memory performance (i.e., accessibility of emotional memories). Undergraduates (N = 60) studied word-image pairs and rated the retrieved image on vividness and emotionality when cued with the word. Then they viewed the cues and recalled the images with or without making EM. Finally, they re-rated the images on vividness and emotionality. Additionally, fragments from images from all conditions were presented and participants identified which fragment was paired earlier with which cue. Findings showed no effect of the dual-task manipulation on self-reported ratings and latency responses. Several possible explanations for the lack of effects are discussed, but the cued recall procedure in our experiment seems to explain the absence of effects best. The study demonstrates boundaries to the effects of the “dual-tasking” procedure. PMID:25729370

The effect of zinc supplementation of lactating rats on short-term and long-term memory of their male offspring.

PubMed

Karami, Mohammad; Ehsanivostacolaee, Simin; Moazedi, Ali Ahmad; Nosrati, Anahita

2013-01-01

In this study the effect of zinc chloride (ZnCl2) administration on the short-term and long-term memory of rats were assessed. We enrolled six groups of adult female and control group of eight Wistar rats in each group. One group was control group with free access to food and water, and five groups drunk zinc chloride in different doses (20, 30, 50, 70 and 100 mg/kg/day) in drinking water for two weeks during lactation .One month after birth, a shuttle box used to short- term and long-term memory and the latency in entering the dark chamber as well. This experiment showed that maternal 70 mg/kg dietary zinc during lactation influenced the working memory of rats' offspring in all groups. Rats received 100 mg/kg/day zinc during lactation so they had significant impairment in working memory (short-term) of their offspring (P<0.05). There was no significant difference in reference (long-term) memory of all groups. Drug consumption below70 mg/kg/day zinc chloride during lactation had no effect. While enhanced 100 mg/ kg/ day zinc in lactating rats could cause short-term memory impairment.

A critical role for STAT3 transcription factor signaling in the development and maintenance of human T cell memory.

PubMed

Siegel, Andrea M; Heimall, Jennifer; Freeman, Alexandra F; Hsu, Amy P; Brittain, Erica; Brenchley, Jason M; Douek, Daniel C; Fahle, Gary H; Cohen, Jeffrey I; Holland, Steven M; Milner, Joshua D

2011-11-23

STAT3 transcription factor signaling in specific T helper cell differentiation has been well described, although the broader roles for STAT3 in lymphocyte memory are less clear. Patients with autosomal-dominant hyper-IgE syndrome (AD-HIES) carry dominant-negative STAT3 mutations and are susceptible to a variety of bacterial and fungal infections. We found that AD-HIES patients have a cell-intrinsic defect in the number of central memory CD4(+) and CD8(+) T cells compared to healthy controls. Naive T cells from AD-HIES patients had lower expression of memory-related transcription factors BCL6 and SOCS3, a primary proliferation defect, and they failed to acquire central memory-like surface phenotypes in vitro. AD-HIES patients showed a decreased ability to control varicella zoster virus (VZV) and Epstein-Barr virus (EBV) latency, and T cell memory to both of these viruses was compromised. These data point to a specific role for STAT3 in human central memory T cell formation and in control of certain chronic viruses. Copyright © 2011 Elsevier Inc. All rights reserved.

Radiation Effects of Commercial Resistive Random Access Memories

NASA Technical Reports Server (NTRS)

Chen, Dakai; LaBel, Kenneth A.; Berg, Melanie; Wilcox, Edward; Kim, Hak; Phan, Anthony; Figueiredo, Marco; Buchner, Stephen; Khachatrian, Ani; Roche, Nicolas

2014-01-01

We present results for the single-event effect response of commercial production-level resistive random access memories. We found that the resistive memory arrays are immune to heavy ion-induced upsets. However, the devices were susceptible to single-event functional interrupts, due to upsets from the control circuits. The intrinsic radiation tolerant nature of resistive memory makes the technology an attractive consideration for future space applications.

Using Video Game Telemetry Data to Research Motor Chunking, Action Latencies, and Complex Cognitive-Motor Skill Learning.

PubMed

Thompson, Joseph J; McColeman, C M; Stepanova, Ekaterina R; Blair, Mark R

2017-04-01

Many theories of complex cognitive-motor skill learning are built on the notion that basic cognitive processes group actions into easy-to-perform sequences. The present work examines predictions derived from laboratory-based studies of motor chunking and motor preparation using data collected from the real-time strategy video game StarCraft 2. We examined 996,163 action sequences in the telemetry data of 3,317 players across seven levels of skill. As predicted, the latency to the first action (thought to be the beginning of a chunked sequence) is delayed relative to the other actions in the group. Other predictions, inspired by the memory drum theory of Henry and Rogers, received only weak support. Copyright © 2017 Cognitive Science Society, Inc.

Intraindividual variability in cognitive performance in older adults: comparison of adults with mild dementia, adults with arthritis, and healthy adults.

PubMed

Hultsch, D F; MacDonald, S W; Hunter, M A; Levy-Bencheton, J; Strauss, E

2000-10-01

Intraindividual variability in latency and accuracy of cognitive performance across both trials and occasions was examined in 3 groups of older adults: healthy adults, adults with arthritis, and adults diagnosed with mild dementia. Participants completed 2 reaction-time and 2 episodic-memory tasks on 4 occasions. Results indicated that intraindividual variability in latency was greater in individuals diagnosed with mild dementia than in adults who were neurologically intact, regardless of their health status. Individual differences in variability were stable over time and across cognitive domains. Intraindividual variability was also related to level of performance and was uniquely predictive of neurological status, independent of level of performance. Results suggest that intraindividual variability may be a behavioral indicator of compromised neurological mechanisms.

The minimal unit of phonological encoding: prosodic or lexical word.

PubMed

Wheeldon, Linda R; Lahiri, Aditi

2002-09-01

Wheeldon and Lahiri (Journal of Memory and Language 37 (1997) 356) used a prepared speech production task (Sternberg, S., Monsell, S., Knoll, R. L., & Wright, C. E. (1978). The latency and duration of rapid movement sequences: comparisons of speech and typewriting. In G. E. Stelmach (Ed.), Information processing in motor control and learning (pp. 117-152). New York: Academic Press; Sternberg, S., Wright, C. E., Knoll, R. L., & Monsell, S. (1980). Motor programs in rapid speech: additional evidence. In R. A. Cole (Ed.), The perception and production of fluent speech (pp. 507-534). Hillsdale, NJ: Erlbaum) to demonstrate that the latency to articulate a sentence is a function of the number of phonological words it comprises. Latencies for the sentence [Ik zoek het] [water] 'I seek the water' were shorter than latencies for sentences like [Ik zoek] [vers] [water] 'I seek fresh water'. We extend this research by examining the prepared production of utterances containing phonological words that are less than a lexical word in length. Dutch compounds (e.g. ooglid 'eyelid') form a single morphosyntactic word and a phonological word, which in turn includes two phonological words. We compare their prepared production latencies to those syntactic phrases consisting of an adjective and a noun (e.g. oud lid 'old member') which comprise two morphosyntactic and two phonological words, and to morphologically simple words (e.g. orgel 'organ') which comprise one morphosyntactic and one phonological word. Our findings demonstrate that the effect is limited to phrasal level phonological words, suggesting that production models need to make a distinction between lexical and phrasal phonology.

Antibody response against Betaferon® in immune tolerant mice: involvement of marginal zone B-cells and CD4+ T-cells and apparent lack of immunological memory.

PubMed

Sauerborn, Melody; van Beers, Miranda M C; Jiskoot, Wim; Kijanka, Grzegorz M; Boon, Louis; Schellekens, Huub; Brinks, Vera

2013-01-01

The immunological processes underlying immunogenicity of recombinant human therapeutics are poorly understood. Using an immune tolerant mouse model we previously demonstrated that aggregates are a major trigger of the antidrug antibody (ADA) response against recombinant human interferon beta (rhIFNβ) products including Betaferon®, and that immunological memory seems to be lacking after a rechallenge with non-aggregated rhIFNβ. The apparent absence of immunological memory indicates a CD4+ T-cell independent (Tind) immune response underlying ADA formation against Betaferon®. This hypothesis was tested. Using the immune tolerant mouse model we first validated that rechallenge with highly aggregated rhIFNβ (Betaferon®) does not lead to a subsequent fast increase in ADA titers, suggesting a lack of immunological memory. Next we assessed whether Betaferon® could act as Tind antigen by inactivation of marginal zone (MZ) B-cells during treatment. MZ B-cells are major effector cells involved in a Tind immune response. In a following experiment we depleted the mice from CD4+ T-cells to test their involvement in the ADA response against Betaferon®. Inactivation of MZ B-cells at the start of Betaferon® treatment drastically lowered ADA levels, suggesting a Tind immune response. However, persistent depletion of CD4+ T-cells before and during Betaferon® treatment abolished the ADA response in almost all mice. The immune response against rhIFNβ in immune tolerant mice is neither a T-cell independent nor a classical T-cell dependent immune response. Further studies are needed to confirm absence of immunological memory (cells).

Self-adaptive Fault-Tolerance of HLA-Based Simulations in the Grid Environment

NASA Astrophysics Data System (ADS)

Huang, Jijie; Chai, Xudong; Zhang, Lin; Li, Bo Hu

The objects of a HLA-based simulation can access model services to update their attributes. However, the grid server may be overloaded and refuse the model service to handle objects accesses. Because these objects have been accessed this model service during last simulation loop and their medium state are stored in this server, this may terminate the simulation. A fault-tolerance mechanism must be introduced into simulations. But the traditional fault-tolerance methods cannot meet the above needs because the transmission latency between a federate and the RTI in grid environment varies from several hundred milliseconds to several seconds. By adding model service URLs to the OMT and expanding the HLA services and model services with some interfaces, this paper proposes a self-adaptive fault-tolerance mechanism of simulations according to the characteristics of federates accessing model services. Benchmark experiments indicate that the expanded HLA/RTI can make simulations self-adaptively run in the grid environment.

Study and response time for the visual recognition of 'similarity' and identity

NASA Technical Reports Server (NTRS)

Derks, P. L.; Bauer, T. M.

1974-01-01

Four subjects compared successively presented pairs of line patterns for a match between any lines in the pattern (similarity) and for a match between all lines (identity). The encoding or study times for pattern recognition from immediate memory and the latency in responses to comparison stimuli were examined. Qualitative differences within and between subjects were most evident in study times.

Low-Latency and Energy-Efficient Data Preservation Mechanism in Low-Duty-Cycle Sensor Networks.

PubMed

Jiang, Chan; Li, Tao-Shen; Liang, Jun-Bin; Wu, Heng

2017-05-06

Similar to traditional wireless sensor networks (WSN), the nodes only have limited memory and energy in low-duty-cycle sensor networks (LDC-WSN). However, different from WSN, the nodes in LDC-WSN often sleep most of their time to preserve their energies. The sleeping feature causes serious data transmission delay. However, each source node that has sensed data needs to quickly disseminate its data to other nodes in the network for redundant storage. Otherwise, data would be lost due to its source node possibly being destroyed by outer forces in a harsh environment. The quick dissemination requirement produces a contradiction with the sleeping delay in the network. How to quickly disseminate all the source data to all the nodes with limited memory in the network for effective preservation is a challenging issue. In this paper, a low-latency and energy-efficient data preservation mechanism in LDC-WSN is proposed. The mechanism is totally distributed. The data can be disseminated to the network with low latency by using a revised probabilistic broadcasting mechanism, and then stored by the nodes with LT (Luby Transform) codes, which are a famous rateless erasure code. After the process of data dissemination and storage completes, some nodes may die due to being destroyed by outer forces. If a mobile sink enters the network at any time and from any place to collect the data, it can recover all of the source data by visiting a small portion of survived nodes in the network. Theoretical analyses and simulation results show that our mechanism outperforms existing mechanisms in the performances of data dissemination delay and energy efficiency.

Lexical selection in the semantically blocked cyclic naming task: the role of cognitive control and learning

PubMed Central

Crowther, Jason E.; Martin, Randi C.

2014-01-01

Studies of semantic interference in language production have provided evidence for a role of cognitive control mechanisms in regulating the activation of semantic competitors during naming. The present study investigated the relationship between individual differences in cognitive control abilities, for both younger and older adults, and the degree of semantic interference in a blocked cyclic naming task. We predicted that individuals with lower working memory capacity (as measured by word span), lesser ability to inhibit distracting responses (as measured by Stroop interference), and a lesser ability to resolve proactive interference (as measured by a recent negatives task) would show a greater increase in semantic interference in naming, with effects being larger for older adults. Instead, measures of cognitive control were found to relate to specific indices of semantic interference in the naming task, rather than overall degree of semantic interference, and few interactions with age were found, with younger and older adults performing similarly. The increase in naming latencies across naming trials within a cycle was negatively correlated with word span for both related and unrelated conditions, suggesting a strategy of narrowing response alternatives based upon memory for the set of item names. Evidence for a role of inhibition in response selection was obtained, as Stroop interference correlated positively with the change in naming latencies across cycles for the related, but not unrelated, condition. In contrast, recent negatives interference correlated negatively with the change in naming latencies across unrelated cycles, suggesting that individual differences in this tap the degree of strengthening of links in a lexical network based upon prior exposure. Results are discussed in terms of current models of lexical selection and consequences for word retrieval in more naturalistic production. PMID:24478675

Functionally Selective Signaling for Morphine and Fentanyl Antinociception and Tolerance Mediated by the Rat Periaqueductal Gray

PubMed Central

Morgan, Michael M.; Reid, Rachel A.; Saville, Kimber A.

2014-01-01

Functionally selective signaling appears to contribute to the variability in mechanisms that underlie tolerance to the antinociceptive effects of opioids. The present study tested this hypothesis by examining the contribution of G protein-coupled receptor kinase (GRK)/Protein kinase C (PKC) and C-Jun N-terminal kinase (JNK) activation on both the expression and development of tolerance to morphine and fentanyl microinjected into the ventrolateral periaqueductal gray of the rat. Microinjection of morphine or fentanyl into the periaqueductal gray produced a dose-dependent increase in hot plate latency. Microinjection of the non-specific GRK/PKC inhibitor Ro 32-0432 into the periaqueductal gray to block mu-opioid receptor phosphorylation enhanced the antinociceptive effect of morphine but had no effect on fentanyl antinociception. Microinjection of the JNK inhibitor SP600125 had no effect on morphine or fentanyl antinociception, but blocked the expression of tolerance to repeated morphine microinjections. In contrast, a microinjection of Ro 32-0432 blocked the expression of fentanyl, but not morphine tolerance. Repeated microinjections of Ro 32-0432 blocked the development of morphine tolerance and inhibited fentanyl antinociception whether rats were tolerant or not. Repeated microinjections of SP600125 into the periaqueductal gray blocked the development of tolerance to both morphine and fentanyl microinjections. These data demonstrate that the signaling molecules that contribute to tolerance vary depending on the opioid and methodology used to assess tolerance (expression vs. development of tolerance). This signaling difference is especially clear for the expression of tolerance in which JNK contributes to morphine tolerance and GRK/PKC contributes to fentanyl tolerance. PMID:25503060

Plasma membrane ordering agent pluronic F-68 (PF-68) reduces neurotransmitter uptake and release and produces learning and memory deficits in rats

NASA Technical Reports Server (NTRS)

Clarke, M. S.; Prendergast, M. A.; Terry, A. V. Jr

1999-01-01

A substantial body of evidence indicates that aged-related changes in the fluidity and lipid composition of the plasma membrane contribute to cellular dysfunction in humans and other mammalian species. In the CNS, reductions in neuronal plasma membrane order (PMO) (i.e., increased plasma membrane fluidity) have been attributed to age as well as the presence of the beta-amyloid peptide-25-35, known to play an important role in the neuropathology of Alzheimer's disease (AD). These PMO increases may influence neurotransmitter synthesis, receptor binding, and second messenger systems as well as signal transduction pathways. The effects of neuronal PMO on learning and memory processes have not been adequately investigated, however. Based on the hypothesis that an increase in PMO may alter a number of aspects of synaptic transmission, we investigated several neurochemical and behavioral effects of the membrane ordering agent, PF-68. In cell culture, PF-68 (nmoles/mg SDS extractable protein) reduced [3H]norepinephrine (NE) uptake into differentiated PC-12 cells as well as reduced nicotine stimulated [3H]NE release. The compound (800-2400 microg/kg, i.p., resulting in nmoles/mg SDS extractable protein in the brain) decreased step-through latencies and increased the frequencies of crossing into the unsafe side of the chamber in inhibitory avoidance training. In the Morris water maze, PF-68 increased the latencies and swim distances required to locate a hidden platform and reduced the time spent and distance swam in the previous target quadrant during transfer (probe) trials. PF-68 did not impair performance of a well-learned working memory task, the rat delayed stimulus discrimination task (DSDT), however. Studies with 14C-labeled PF-68 indicated that significant (pmoles/mg wet tissue) levels of the compound entered the brain from peripheral (i.p.) injection. No PF-68 related changes were observed in swim speeds or in visual acuity tests in water maze experiments, rotorod performance, or in tests of general locomotor activity. Furthermore, latencies to select a lever in the DSDT were not affected. These results suggest that PF-68 induced deficits in learning and memory without confounding peripheral motor, sensory, or motivational effects at the tested doses. Furthermore, none of the doses induced a conditioned taste aversion to a novel 0.1% saccharin solution indicating a lack of nausea or gastrointestinal malaise induced by the compound. The data indicate that increases in neuronal plasma membrane order may have significant effects on neurotransmitter function as well as learning and memory processes. Furthermore, compounds such as PF-68 may also offer novel tools for studying the role of neuronal PMO in mnemonic processes and changes in PMO resulting from age-related disorders such as AD.

Evidence for a differential contribution of early perceptual and late cognitive processes during encoding to episodic memory impairment in schizophrenia.

PubMed

Green, Amity E; Fitzgerald, Paul B; Johnston, Patrick J; Nathan, Pradeep J; Kulkarni, Jayashri; Croft, Rodney J

2017-08-01

Schizophrenia is characterised by significant episodic memory impairment that is thought to be related to problems with encoding, however the neuro-functional mechanisms underlying these deficits are not well understood. The present study used a subsequent recognition memory paradigm and event-related potentials (ERPs) to investigate temporal aspects of episodic memory encoding deficits in schizophrenia. Electroencephalographic data was recorded in 24 patients and 19 healthy controls whilst participants categorised single words as pleasant/unpleasant. ERPs were generated to subsequently recognised versus unrecognised words on the basis of a forced-choice recognition memory task. Subsequent memory effects were examined with the late positive component (LPP). Group differences in N1, P2, N400 and LPP were examined for words correctly recognised. Patients performed more poorly than controls on the recognition task. During encoding patients had significantly reduced N400 and LPP amplitudes than controls. LPP amplitude correlated with task performance however amplitudes did not differ between patients and controls as a function of subsequent memory. No significant differences in N1 or P2 amplitude or latency were observed. The present results indicate that early sensory processes are intact and dysfunctional higher order cognitive processes during encoding are contributing to episodic memory impairments in schizophrenia.

Complexity Optimization and High-Throughput Low-Latency Hardware Implementation of a Multi-Electrode Spike-Sorting Algorithm

PubMed Central

Dragas, Jelena; Jäckel, David; Hierlemann, Andreas; Franke, Felix

2017-01-01

Reliable real-time low-latency spike sorting with large data throughput is essential for studies of neural network dynamics and for brain-machine interfaces (BMIs), in which the stimulation of neural networks is based on the networks' most recent activity. However, the majority of existing multi-electrode spike-sorting algorithms are unsuited for processing high quantities of simultaneously recorded data. Recording from large neuronal networks using large high-density electrode sets (thousands of electrodes) imposes high demands on the data-processing hardware regarding computational complexity and data transmission bandwidth; this, in turn, entails demanding requirements in terms of chip area, memory resources and processing latency. This paper presents computational complexity optimization techniques, which facilitate the use of spike-sorting algorithms in large multi-electrode-based recording systems. The techniques are then applied to a previously published algorithm, on its own, unsuited for large electrode set recordings. Further, a real-time low-latency high-performance VLSI hardware architecture of the modified algorithm is presented, featuring a folded structure capable of processing the activity of hundreds of neurons simultaneously. The hardware is reconfigurable “on-the-fly” and adaptable to the nonstationarities of neuronal recordings. By transmitting exclusively spike time stamps and/or spike waveforms, its real-time processing offers the possibility of data bandwidth and data storage reduction. PMID:25415989

Complexity optimization and high-throughput low-latency hardware implementation of a multi-electrode spike-sorting algorithm.

PubMed

Dragas, Jelena; Jackel, David; Hierlemann, Andreas; Franke, Felix

2015-03-01

Reliable real-time low-latency spike sorting with large data throughput is essential for studies of neural network dynamics and for brain-machine interfaces (BMIs), in which the stimulation of neural networks is based on the networks' most recent activity. However, the majority of existing multi-electrode spike-sorting algorithms are unsuited for processing high quantities of simultaneously recorded data. Recording from large neuronal networks using large high-density electrode sets (thousands of electrodes) imposes high demands on the data-processing hardware regarding computational complexity and data transmission bandwidth; this, in turn, entails demanding requirements in terms of chip area, memory resources and processing latency. This paper presents computational complexity optimization techniques, which facilitate the use of spike-sorting algorithms in large multi-electrode-based recording systems. The techniques are then applied to a previously published algorithm, on its own, unsuited for large electrode set recordings. Further, a real-time low-latency high-performance VLSI hardware architecture of the modified algorithm is presented, featuring a folded structure capable of processing the activity of hundreds of neurons simultaneously. The hardware is reconfigurable “on-the-fly” and adaptable to the nonstationarities of neuronal recordings. By transmitting exclusively spike time stamps and/or spike waveforms, its real-time processing offers the possibility of data bandwidth and data storage reduction.

The Asymmetrical Effects of Divided Attention on Encoding and Retrieval Processes: A Different View Based on an Interference with the Episodic Register

PubMed Central

Guez, Jonathan; Naveh-Benjamin, Moshe

2013-01-01

In this study, we evaluate the conceptualization of encoding and retrieval processes established in previous studies that used a divided attention (DA) paradigm. These studies indicated that there were considerable detrimental effects of DA at encoding on later memory performance, but only minimal effects, if any, on divided attention at retrieval. We suggest that this asymmetry in the effects of DA on memory can be due, at least partially, to a confound between the memory phase (encoding and retrieval) and the memory requirements of the task (memory “for” encoded information versus memory “at” test). To control for this confound, we tested memory for encoded information and for retrieved information by introducing a second test that assessed memory for the retrieved information from the first test. We report the results of four experiments that use measures of memory performance, retrieval latency, and performance on the concurrent task, all of which consistently show that DA at retrieval strongly disrupts later memory for the retrieved episode, similarly to the effects of DA at encoding. We suggest that these symmetrical disruptive effects of DA at encoding and retrieval on later retrieval reflect a disruption of an episodic buffer (EB) or episodic register component (ER), rather than a failure of encoding or retrieval operations per se. PMID:24040249

The asymmetrical effects of divided attention on encoding and retrieval processes: a different view based on an interference with the episodic register.

PubMed

Guez, Jonathan; Naveh-Benjamin, Moshe

2013-01-01

In this study, we evaluate the conceptualization of encoding and retrieval processes established in previous studies that used a divided attention (DA) paradigm. These studies indicated that there were considerable detrimental effects of DA at encoding on later memory performance, but only minimal effects, if any, on divided attention at retrieval. We suggest that this asymmetry in the effects of DA on memory can be due, at least partially, to a confound between the memory phase (encoding and retrieval) and the memory requirements of the task (memory "for" encoded information versus memory "at" test). To control for this confound, we tested memory for encoded information and for retrieved information by introducing a second test that assessed memory for the retrieved information from the first test. We report the results of four experiments that use measures of memory performance, retrieval latency, and performance on the concurrent task, all of which consistently show that DA at retrieval strongly disrupts later memory for the retrieved episode, similarly to the effects of DA at encoding. We suggest that these symmetrical disruptive effects of DA at encoding and retrieval on later retrieval reflect a disruption of an episodic buffer (EB) or episodic register component (ER), rather than a failure of encoding or retrieval operations per se.

Endogenous Memory CD8 T Cells Directly Mediate Cardiac Allograft Rejection

PubMed Central

Su, C. A.; Iida, S.; Abe, T.; Fairchild, R. L.

2014-01-01

Differences in levels of environmentally induced memory T cells that cross-react with donor MHC molecules are postulated to account for the efficacy of allograft tolerance inducing strategies in rodents versus their failure in nonhuman primates and human transplant patients. Strategies to study the impact of donor-reactive memory T cells on allografts in rodents have relied on the pre-transplant induction of memory T cells cross-reactive with donor allogeneic MHC molecules through recipient viral infection, priming directly with donor antigen, or adoptive transfer of donor-antigen primed memory T cells. Each approach accelerates allograft rejection and confers resistance to tolerance induction, but also biases the T cell repertoire to strong donor-reactivity. The ability of endogenous memory T cells within unprimed mice to directly reject an allograft is unknown. Here we show a direct association between increased duration of cold ischemic allograft storage and numbers and enhanced functions of early graft infiltrating endogenous CD8 memory T cells. These T cells directly mediate rejection of allografts subjected to prolonged ischemia and this rejection is resistant to costimulatory blockade. These findings recapitulate the clinically significant impact of endogenous memory T cells with donor reactivity in a mouse transplant model in the absence of prior recipient priming. PMID:24502272

Power Aware Distributed Systems

DTIC Science & Technology

2004-01-01

detection or threshold functions to trigger the main CPU. The main processor can sleep and either wakeup on a schedule or by a positive threshold event...the RTOS must determine if wake-up latency can be tolerated (or, if it could be hidden by pre- wakeup ). The prediction accuracy for scheduling ...and processor shutdown/ wakeup . This analysis can be used to accurately analyze the schedulability of non-concrete periodic task sets, scheduled using

Long-term contextual memory in infant rats as evidenced by an ethanol conditioned tolerance procedure.

PubMed

Castelló, Stefanía; Molina, Juan Carlos; Arias, Carlos

2017-08-14

Conditioned tolerance can be conceptualized as a particular case of Pavlovian conditioning in which contextual cues play the role of the conditioned stimulus. Although the evidence is contradictory, it is frequently assumed that long-term contextual conditioning in pre-weanling rats is weak or even absent. This hypothesis comes from and is sustained mainly by behavioral studies that explored different contextual effects in 16-18day-old rats using a fear-conditioning paradigm, but their conclusions are stated in terms of an immature (hippocampal-dependent) declarative memory system. The main goal of the present manuscript was based on a recent antecedent from our laboratory, to analyze whether context-dependent tolerance induced by ethanol during the pre-weanling period persists over time. Results showed that the context was able to modulate ethanol-induced tolerance in 2- and 3-week-old rats. Interestingly, contextual conditioned tolerance was stronger (in terms of persistence) during the third than during the second postnatal week. When subjects were tested 8days after training, when the context presumably lost its influence over tolerance, the opposite effect emerged (sensitization). These results are important for the ethanol literature, adding new evidence of long-term retention of ethanol effects acquired during infancy, whilst also showing striking ontogenetic differences in the sensitivity to ethanol between the 2nd and 3rd postnatal weeks. Importantly, contextual information modulates the expression of these ethanol effects even eight days after training, a result that is particularly relevant to the discussion of the ontogeny of contextual memory. Copyright © 2017 Elsevier B.V. All rights reserved.

Low-Dose Cannabinoid Type 2 Receptor Agonist Attenuates Tolerance to Repeated Morphine Administration via Regulating μ-Opioid Receptor Expression in Walker 256 Tumor-Bearing Rats.

PubMed

Zhang, Mingyue; Wang, Kun; Ma, Min; Tian, Songyu; Wei, Na; Wang, Guonian

2016-04-01

Morphine is widely used in patients with moderate and severe cancer pain, whereas the development of drug tolerance remains a major problem associated with opioid use. Previous studies have shown that cannabinoid type 2 (CB2) receptor agonists induce morphine analgesia, attenuate morphine tolerance in normal and neuropathic pain animals, induce transcription of the μ-opioid receptor (MOR) gene in Jurkat T cells, and increase morphine analgesia in cancer pain animals. However, no studies of the effects of CB2 receptor agonists on morphine tolerance in cancer pain have been performed. Therefore, we investigated the effect of repeated intrathecal (IT) injection of the low-dose CB2 receptor agonist AM1241 on the development of morphine tolerance in walker 256 tumor-bearing rats. We also tested the influence of the CB2 receptor agonist AM1241 on MOR protein and messenger ribonucleic acid (mRNA) expression in the rat spinal cord and dorsal root ganglia (DRG). Walker 256 cells were implanted into the plantar region of each rat's right hindpaw. Tumor-bearing rats received IT injection of the CB2 receptor agonist AM1241 or antagonist AM630 with or without morphine subcutaneously twice daily for 8 days. Rats receiving drug vehicle only served as the control group. Mechanical paw withdrawal threshold and thermal paw withdrawal latency were assessed by a von Frey test and hot plate test 30 minutes after drug administration every day. MOR protein and mRNA expression in the spinal cord and DRG were detected after the last day (day 8) of drug administration via Western blot and real-time reverse transcription polymerase chain reaction. The data were analyzed via analysis of variance followed by Student t test with Bonferroni correction for multiple comparisons. Repeated morphine treatments reduced the mechanical withdrawal threshold and thermal latency. Coadministration of a nonanalgetic dose of the CB2 receptor agonist AM1241 with morphine significantly inhibited the development of morphine tolerance and increased the MOR protein expression in the spinal cord and DRG and mRNA expression in the spinal cord in tumor-bearing rats. Our findings indicate that IT injection of a nonanalgetic dose of a CB2 receptor agonist increased the analgesia effect and alleviated tolerance to morphine in tumor-bearing rats, potentially by regulating MOR expression in the spinal cord and DRG. This receptor may be a new target for prevention of the development of opioid tolerance in cancer pain.

Latency Hiding in Dynamic Partitioning and Load Balancing of Grid Computing Applications

NASA Technical Reports Server (NTRS)

Das, Sajal K.; Harvey, Daniel J.; Biswas, Rupak

2001-01-01

The Information Power Grid (IPG) concept developed by NASA is aimed to provide a metacomputing platform for large-scale distributed computations, by hiding the intricacies of highly heterogeneous environment and yet maintaining adequate security. In this paper, we propose a latency-tolerant partitioning scheme that dynamically balances processor workloads on the.IPG, and minimizes data movement and runtime communication. By simulating an unsteady adaptive mesh application on a wide area network, we study the performance of our load balancer under the Globus environment. The number of IPG nodes, the number of processors per node, and the interconnected speeds are parameterized to derive conditions under which the IPG would be suitable for parallel distributed processing of such applications. Experimental results demonstrate that effective solution are achieved when the IPG nodes are connected by a high-speed asynchronous interconnection network.

Performance analysis of three-dimensional-triple-level cell and two-dimensional-multi-level cell NAND flash hybrid solid-state drives

NASA Astrophysics Data System (ADS)

Sakaki, Yukiya; Yamada, Tomoaki; Matsui, Chihiro; Yamaga, Yusuke; Takeuchi, Ken

2018-04-01

In order to improve performance of solid-state drives (SSDs), hybrid SSDs have been proposed. Hybrid SSDs consist of more than two types of NAND flash memories or NAND flash memories and storage-class memories (SCMs). However, the cost of hybrid SSDs adopting SCMs is more expensive than that of NAND flash only SSDs because of the high bit cost of SCMs. This paper proposes unique hybrid SSDs with two-dimensional (2D) horizontal multi-level cell (MLC)/three-dimensional (3D) vertical triple-level cell (TLC) NAND flash memories to achieve higher cost-performance. The 2D-MLC/3D-TLC hybrid SSD achieves up to 31% higher performance than the conventional 2D-MLC/2D-TLC hybrid SSD. The factors of different performance between the proposed hybrid SSD and the conventional hybrid SSD are analyzed by changing its block size, read/write/erase latencies, and write unit of 3D-TLC NAND flash memory, by means of a transaction-level modeling simulator.

JuxtaView - A tool for interactive visualization of large imagery on scalable tiled displays

USGS Publications Warehouse

Krishnaprasad, N.K.; Vishwanath, V.; Venkataraman, S.; Rao, A.G.; Renambot, L.; Leigh, J.; Johnson, A.E.; Davis, B.

2004-01-01

JuxtaView is a cluster-based application for viewing ultra-high-resolution images on scalable tiled displays. We present in JuxtaView, a new parallel computing and distributed memory approach for out-of-core montage visualization, using LambdaRAM, a software-based network-level cache system. The ultimate goal of JuxtaView is to enable a user to interactively roam through potentially terabytes of distributed, spatially referenced image data such as those from electron microscopes, satellites and aerial photographs. In working towards this goal, we describe our first prototype implemented over a local area network, where the image is distributed using LambdaRAM, on the memory of all nodes of a PC cluster driving a tiled display wall. Aggressive pre-fetching schemes employed by LambdaRAM help to reduce latency involved in remote memory access. We compare LambdaRAM with a more traditional memory-mapped file approach for out-of-core visualization. ?? 2004 IEEE.

High Performance Data Transfer for Distributed Data Intensive Sciences

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

Fang, Chin; Cottrell, R 'Les' A.; Hanushevsky, Andrew B.

We report on the development of ZX software providing high performance data transfer and encryption. The design scales in: computation power, network interfaces, and IOPS while carefully balancing the available resources. Two U.S. patent-pending algorithms help tackle data sets containing lots of small files and very large files, and provide insensitivity to network latency. It has a cluster-oriented architecture, using peer-to-peer technologies to ease deployment, operation, usage, and resource discovery. Its unique optimizations enable effective use of flash memory. Using a pair of existing data transfer nodes at SLAC and NERSC, we compared its performance to that of bbcp andmore » GridFTP and determined that they were comparable. With a proof of concept created using two four-node clusters with multiple distributed multi-core CPUs, network interfaces and flash memory, we achieved 155Gbps memory-to-memory over a 2x100Gbps link aggregated channel and 70Gbps file-to-file with encryption over a 5000 mile 100Gbps link.« less

Analysis on applicable error-correcting code strength of storage class memory and NAND flash in hybrid storage

NASA Astrophysics Data System (ADS)

Matsui, Chihiro; Kinoshita, Reika; Takeuchi, Ken

2018-04-01

A hybrid of storage class memory (SCM) and NAND flash is a promising technology for high performance storage. Error correction is inevitable on SCM and NAND flash because their bit error rate (BER) increases with write/erase (W/E) cycles, data retention, and program/read disturb. In addition, scaling and multi-level cell technologies increase BER. However, error-correcting code (ECC) degrades storage performance because of extra memory reading and encoding/decoding time. Therefore, applicable ECC strength of SCM and NAND flash is evaluated independently by fixing ECC strength of one memory in the hybrid storage. As a result, weak BCH ECC with small correctable bit is recommended for the hybrid storage with large SCM capacity because SCM is accessed frequently. In contrast, strong and long-latency LDPC ECC can be applied to NAND flash in the hybrid storage with large SCM capacity because large-capacity SCM improves the storage performance.

Method for prefetching non-contiguous data structures

DOEpatents

Blumrich, Matthias A [Ridgefield, CT; Chen, Dong [Croton On Hudson, NY; Coteus, Paul W [Yorktown Heights, NY; Gara, Alan G [Mount Kisco, NY; Giampapa, Mark E [Irvington, NY; Heidelberger, Philip [Cortlandt Manor, NY; Hoenicke, Dirk [Ossining, NY; Ohmacht, Martin [Brewster, NY; Steinmacher-Burow, Burkhard D [Mount Kisco, NY; Takken, Todd E [Mount Kisco, NY; Vranas, Pavlos M [Bedford Hills, NY

2009-05-05

A low latency memory system access is provided in association with a weakly-ordered multiprocessor system. Each processor in the multiprocessor shares resources, and each shared resource has an associated lock within a locking device that provides support for synchronization between the multiple processors in the multiprocessor and the orderly sharing of the resources. A processor only has permission to access a resource when it owns the lock associated with that resource, and an attempt by a processor to own a lock requires only a single load operation, rather than a traditional atomic load followed by store, such that the processor only performs a read operation and the hardware locking device performs a subsequent write operation rather than the processor. A simple perfecting for non-contiguous data structures is also disclosed. A memory line is redefined so that in addition to the normal physical memory data, every line includes a pointer that is large enough to point to any other line in the memory, wherein the pointers to determine which memory line to prefect rather than some other predictive algorithm. This enables hardware to effectively prefect memory access patterns that are non-contiguous, but repetitive.

Tolerance to Non-Opioid Analgesics is Opioid Sensitive in the Nucleus Raphe Magnus.

PubMed

Tsagareli, Merab G; Nozadze, Ivliane; Tsiklauri, Nana; Gurtskaia, Gulnaz

2011-01-01

Repeated injection of opioid analgesics can lead to a progressive loss of effect. This phenomenon is known as tolerance. Several lines of investigations have shown that systemic, intraperitoneal administration or the microinjection of non-opioid analgesics, non-steroidal anti-inflammatory drugs (NSAIDs) into the midbrain periaqueductal gray matter induces antinociception with some effects of tolerance. Our recent study has revealed that microinjection of three drugs analgin, ketorolac, and xefocam into the central nucleus of amygdala produce tolerance to them and cross-tolerance to morphine. Here we report that repeated administrations of these NSAIDs into the nucleus raphe magnus (NRM) in the following 4 days result in progressively less antinociception compare to the saline control, i.e., tolerance develops to these drugs in male rats. Special control experiments showed that post-treatment with the μ-opioid antagonist naloxone into the NRM significantly decreased antinociceptive effects of NSAIDs on the first day of testing in the tail-flick (TF) reflex and hot plate (HP) latency tests. On the second day, naloxone generally had trend effects in both TF and HP tests and impeded the development of tolerance to the antinociceptive effect of non-opioid analgesics. These findings strongly support the suggestion of endogenous opioid involvement in NSAIDs antinociception and tolerance in the descending pain-control system. Moreover, repeated injections of NSAIDs progressively lead to tolerance to them, cross-tolerance to morphine, and the risk of a withdrawal syndrome. Therefore, these results are important for human medicine too.

Multi-petascale highly efficient parallel supercomputer

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

Asaad, Sameh; Bellofatto, Ralph E.; Blocksome, Michael A.

A Multi-Petascale Highly Efficient Parallel Supercomputer of 100 petaflop-scale includes node architectures based upon System-On-a-Chip technology, where each processing node comprises a single Application Specific Integrated Circuit (ASIC). The ASIC nodes are interconnected by a five dimensional torus network that optimally maximize the throughput of packet communications between nodes and minimize latency. The network implements collective network and a global asynchronous network that provides global barrier and notification functions. Integrated in the node design include a list-based prefetcher. The memory system implements transaction memory, thread level speculation, and multiversioning cache that improves soft error rate at the same time andmore » supports DMA functionality allowing for parallel processing message-passing.« less

A 300MHz Embedded Flash Memory with Pipeline Architecture and Offset-Free Sense Amplifiers for Dual-Core Automotive Microcontrollers

NASA Astrophysics Data System (ADS)

Kajiyama, Shinya; Fujito, Masamichi; Kasai, Hideo; Mizuno, Makoto; Yamaguchi, Takanori; Shinagawa, Yutaka

A novel 300MHz embedded flash memory for dual-core microcontrollers with a shared ROM architecture is proposed. One of its features is a three-stage pipeline read operation, which enables reduced access pitch and therefore reduces performance penalty due to conflict of shared ROM accesses. Another feature is a highly sensitive sense amplifier that achieves efficient pipeline operation with two-cycle latency one-cycle pitch as a result of a shortened sense time of 0.63ns. The combination of the pipeline architecture and proposed sense amplifiers significantly reduces access-conflict penalties with shared ROM and enhances performance of 32-bit RISC dual-core microcontrollers by 30%.

Error recovery in shared memory multiprocessors using private caches

NASA Technical Reports Server (NTRS)

Wu, Kun-Lung; Fuchs, W. Kent; Patel, Janak H.

1990-01-01

The problem of recovering from processor transient faults in shared memory multiprocesses systems is examined. A user-transparent checkpointing and recovery scheme using private caches is presented. Processes can recover from errors due to faulty processors by restarting from the checkpointed computation state. Implementation techniques using checkpoint identifiers and recovery stacks are examined as a means of reducing performance degradation in processor utilization during normal execution. This cache-based checkpointing technique prevents rollback propagation, provides rapid recovery, and can be integrated into standard cache coherence protocols. An analytical model is used to estimate the relative performance of the scheme during normal execution. Extensions to take error latency into account are presented.

Age-related effects on perceptual and semantic encoding in memory.

PubMed

Kuo, M C C; Liu, K P Y; Ting, K H; Chan, C C H

2014-03-07

This study examined the age-related subsequent memory effect (SME) in perceptual and semantic encoding using event-related potentials (ERPs). Seventeen younger adults and 17 older adults studied a series of Chinese characters either perceptually (by inspecting orthographic components) or semantically (by determining whether the depicted object makes sounds). The two tasks had similar levels of difficulty. The participants made studied or unstudied judgments during the recognition phase. Younger adults performed better in both conditions, with significant SMEs detected in the time windows of P2, N3, P550, and late positive component (LPC). In the older group, SMEs were observed in the P2 and N3 latencies in both conditions but were only detected in the P550 in the semantic condition. Between-group analyses showed larger frontal and central SMEs in the younger sample in the LPC latency regardless of encoding type. Aging effect appears to be stronger on influencing perceptual than semantic encoding processes. The effects seem to be associated with a decline in updating and maintaining representations during perceptual encoding. The age-related decline in the encoding function may be due in part to changes in frontal lobe function. Copyright © 2013 IBRO. Published by Elsevier Ltd. All rights reserved.

Phosphodiesterase type 1 inhibition improves learning in rats exposed to alcohol during the third trimester equivalent of human gestation

PubMed Central

Filgueiras, Claudio C.; Krahe, Thomas E.; Medina, Alexandre E.

2010-01-01

Deficits in learning and memory have been extensively observed in animal models of fetal alcohol spectrum disorders (FASD). Here we use the Morris Maze to test whether Vinpocetine, a Phosphodiesterase type 1 inhibitor, restores learning performance in rats exposed to alcohol during the third trimester equivalent of human gestation. Long Evans rats received ethanol (5 g/Kg ip) or saline on alternate days from postnatal day (P) 4 to P10. Two weeks later (P25), the latency to find a hidden platform was evaluated (2 trials per day spaced at 40-min inter-trial intervals) during 4 consecutive days. Vinpocetine treatment started on the first day of behavioral testing: animals received vinpocetine (20 mg/kg ip) or vehicle solution every other day until the end of behavioral procedures. Early alcohol exposure significantly affected the performance to find the hidden platform. The average latency of ethanol exposed animals was significantly higher than that observed for the control group. Treatment of alcohol-exposed animals with vinpocetine restored their performance to control levels. Our results show that inhibition of PDE1 improves learning and memory deficits in rats early exposed to alcohol and provide evidence for the potential therapeutic use of vinpocetine in FASD. PMID:20219634

REM sleep behavior disorder and narcoleptic features in anti-Ma2-associated encephalitis.

PubMed

Compta, Yaroslau; Iranzo, Alex; Santamaría, Joan; Casamitjana, Roser; Graus, Francesc

2007-06-01

A 69-year-old man with anti-Ma2 paraneoplastic encephalitis presented with subacute onset of severe hypersomnia, memory loss, parkinsonism, and gaze palsy. A brain magnetic resonance imaging study showed bilateral damage in the dorsolateral midbrain, amygdala, and paramedian thalami. Videopolysomnography disclosed rapid eye movement (REM) sleep behavior disorder, and a Multiple Sleep Latency Test showed a mean sleep latency of 7 minutes and 4 sleep-onset REM periods. The level of hypocretin-1 in the cerebrospinal fluid was low (49 pg/mL). This observation illustrates that REM sleep behavior disorder and narcoleptic features are 2 REM-sleep abnormalities that (1) may share the same autoimmune-mediated origin affecting the brainstem, limbic, and diencephalic structures and (2) may occur in the setting of the paraneoplastic anti-Ma2-associated encephalitis.

Differential Effects of Alcohol on Memory Performance in Adolescent Men and Women with a Binge Drinking History.

PubMed

Vinader-Caerols, Concepción; Talk, Andrew; Montañés, Adriana; Duque, Aránzazu; Monleón, Santiago

2017-09-01

Binge drinking (BD) is characterized by intermittent consumption of large quantities of alcohol in short periods. This pattern of drinking is prevalent among adolescents, and has been associated with undermined learning and memory ability. This study investigates the relationships between a history of BD and the effects of acute exposure to alcohol on learning and memory performance in adolescent men and women. A high, acute dose of alcohol or control refreshment was administered to a sample of 172 adolescent undergraduate students, some of which had a history of BD and others of which had refrained from alcohol consumption. Subsequently, immediate visual memory (IVM) and working memory (WM) was measured according to the Wechsler Memory Scale in females and males with different BAC (Experiment 1) and similar BAC (Experiment 2). In both experiments, IVM was reduced after acute alcohol consumption and there was no significant main effect of Drinking Pattern. Furthermore, an effect of cognitive alcohol tolerance on IVM was observed in women but not in men. WM was not affected by alcohol, but a gender difference was evident in that performance was superior in men than in women. In adolescents, IVM is more sensitive than WM to impairment by alcohol, and women are more vulnerable to the neurotoxic effects of alcohol than men, since the cognitive tolerance effect of alcohol on IVM develops in BD women but not in BD men. These findings emphasize the need to investigate the neurotoxic effects of alcohol in adolescent women. In adolescents, immediate visual memory (IVM) is more sensitive than working memory to impairment by alcohol, and women are more vulnerable to the neurotoxic effects of alcohol than men, because the cognitive tolerance effect of alcohol on IVM develops in binge drinking (BD) women but not in BD men. © The Author 2017. Medical Council on Alcohol and Oxford University Press. All rights reserved.

FPGA-Based, Self-Checking, Fault-Tolerant Computers

NASA Technical Reports Server (NTRS)

Some, Raphael; Rennels, David

2004-01-01

A proposed computer architecture would exploit the capabilities of commercially available field-programmable gate arrays (FPGAs) to enable computers to detect and recover from bit errors. The main purpose of the proposed architecture is to enable fault-tolerant computing in the presence of single-event upsets (SEUs). [An SEU is a spurious bit flip (also called a soft error) caused by a single impact of ionizing radiation.] The architecture would also enable recovery from some soft errors caused by electrical transients and, to some extent, from intermittent and permanent (hard) errors caused by aging of electronic components. A typical FPGA of the current generation contains one or more complete processor cores, memories, and highspeed serial input/output (I/O) channels, making it possible to shrink a board-level processor node to a single integrated-circuit chip. Custom, highly efficient microcontrollers, general-purpose computers, custom I/O processors, and signal processors can be rapidly and efficiently implemented by use of FPGAs. Unfortunately, FPGAs are susceptible to SEUs. Prior efforts to mitigate the effects of SEUs have yielded solutions that degrade performance of the system and require support from external hardware and software. In comparison with other fault-tolerant- computing architectures (e.g., triple modular redundancy), the proposed architecture could be implemented with less circuitry and lower power demand. Moreover, the fault-tolerant computing functions would require only minimal support from circuitry outside the central processing units (CPUs) of computers, would not require any software support, and would be largely transparent to software and to other computer hardware. There would be two types of modules: a self-checking processor module and a memory system (see figure). The self-checking processor module would be implemented on a single FPGA and would be capable of detecting its own internal errors. It would contain two CPUs executing identical programs in lock step, with comparison of their outputs to detect errors. It would also contain various cache local memory circuits, communication circuits, and configurable special-purpose processors that would use self-checking checkers. (The basic principle of the self-checking checker method is to utilize logic circuitry that generates error signals whenever there is an error in either the checker or the circuit being checked.) The memory system would comprise a main memory and a hardware-controlled check-pointing system (CPS) based on a buffer memory denoted the recovery cache. The main memory would contain random-access memory (RAM) chips and FPGAs that would, in addition to everything else, implement double-error-detecting and single-error-correcting memory functions to enable recovery from single-bit errors.

Inhibition of Histone Deacetylases (HDACs) and mTOR Signaling: Novel Strategies Toward the Treatment of Prostate Cancer

DTIC Science & Technology

2011-04-01

castrate resistant pros- tate cancer that initially undergoes a latency period (possibly quiescent low proliferating tumors as docu- mented in the...our results demonstrate that low dose concurrent panobinostat/everolimus combination therapy is well tolerated and results in greater anti-tumor...and dose dependent manner, where as Myc-CaP cell lines were resistant to the cytotoxic effects of everolimus. Treatment with low dose (non

A set-associative, fault-tolerant cache design

NASA Technical Reports Server (NTRS)

Lamet, Dan; Frenzel, James F.

1992-01-01

The design of a defect-tolerant control circuit for a set-associative cache memory is presented. The circuit maintains the stack ordering necessary for implementing the Least Recently Used (LRU) replacement algorithm. A discussion of programming techniques for bypassing defective blocks is included.

Activating representations in permanent memory: different benefits for pictures and words.

PubMed

Seifert, L S

1997-09-01

Previous research has suggested that pictures have privileged access to semantic memory (W. R. Glaser, 1992), but J. Theios and P. C. Amrhein (1989b) argued that prior studies inappropriately used large pictures and small words. In Experiment 1, participants categorized pictures reliably faster than words, even when both types of items were of optimal perceptual size. In Experiment 2, a poststimulus flashmask and judgments about internal features did not eliminate picture superiority, indicating that it was not due to differences in early visual processing or analysis of visible features. In Experiment 3, when participants made judgments about whether items were related, latencies were reliably faster for categorically related pictures than for words, but there was no picture advantage for noncategorically associated items. Results indicate that pictures have privileged access to semantic memory for categories, but that neither pictures nor words seem to have privileged access to noncategorical associations.

Divided attention in younger and older adults: effects of strategy and relatedness on memory performance and secondary task costs.

PubMed

Naveh-Benjamin, Moshe; Craik, Fergus I M; Guez, Jonathan; Kreuger, Sharyn

2005-05-01

Divided attention at encoding leads to a significant decline in memory performance, whereas divided attention during retrieval has relatively little effect; nevertheless, retrieval carries significant secondary task costs, especially for older adults. The authors further investigated the effects of divided attention in younger and older adults by using a cued-recall task and by measuring retrieval accuracy, retrieval latency, and the temporal distribution of attentional costs at encoding and retrieval. An age-related memory deficit was reduced by pair relatedness, whereas strategy instructions benefited both age groups equally. Attentional costs were greater for retrieval than for encoding, especially for older adults. These findings are interpreted in light of notions of an age-related associative deficit (M. Naveh-Benjamin, 2000) and age-related differences in the use of self-initiated activities and environmental support (F. I. M. Craik, 1983, 1986).

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

PubMed

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

2012-01-09

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

Fusion PIC code performance analysis on the Cori KNL system

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

Koskela, Tuomas S.; Deslippe, Jack; Friesen, Brian

We study the attainable performance of Particle-In-Cell codes on the Cori KNL system by analyzing a miniature particle push application based on the fusion PIC code XGC1. We start from the most basic building blocks of a PIC code and build up the complexity to identify the kernels that cost the most in performance and focus optimization efforts there. Particle push kernels operate at high AI and are not likely to be memory bandwidth or even cache bandwidth bound on KNL. Therefore, we see only minor benefits from the high bandwidth memory available on KNL, and achieving good vectorization ismore » shown to be the most beneficial optimization path with theoretical yield of up to 8x speedup on KNL. In practice we are able to obtain up to a 4x gain from vectorization due to limitations set by the data layout and memory latency.« less

Recognition errors suggest fast familiarity and slow recollection in rhesus monkeys

PubMed Central

Basile, Benjamin M.; Hampton, Robert R.

2013-01-01

One influential model of recognition posits two underlying memory processes: recollection, which is detailed but relatively slow, and familiarity, which is quick but lacks detail. Most of the evidence for this dual-process model in nonhumans has come from analyses of receiver operating characteristic (ROC) curves in rats, but whether ROC analyses can demonstrate dual processes has been repeatedly challenged. Here, we present independent converging evidence for the dual-process model from analyses of recognition errors made by rhesus monkeys. Recognition choices were made in three different ways depending on processing duration. Short-latency errors were disproportionately false alarms to familiar lures, suggesting control by familiarity. Medium-latency responses were less likely to be false alarms and were more accurate, suggesting onset of a recollective process that could correctly reject familiar lures. Long-latency responses were guesses. A response deadline increased false alarms, suggesting that limiting processing time weakened the contribution of recollection and strengthened the contribution of familiarity. Together, these findings suggest fast familiarity and slow recollection in monkeys, that monkeys use a “recollect to reject” strategy to countermand false familiarity, and that primate recognition performance is well-characterized by a dual-process model consisting of recollection and familiarity. PMID:23864646

Developmental treatment with difluoromethylornithine has few effects on behavior or body weight in Sprague-Dawley rats.

PubMed

Ferguson, Sherry A; Cada, Amy M

2004-01-01

Developmental difluoromethylornithine (DFMO) treatment reduces cerebellar weight [Neuroscience 17 (1986) 399, Neurotoxicol. Teratol. 22 (2000) 415, Behav. Brain Res. 126 (2001) 135], but the functional alterations resulting from this have been little investigated. Here, Sprague-Dawley rats were subcutaneously injected with 500 mg/kg DFMO on postnatal days (PNDs) 5-12 and a comprehensive set of behavioral assessments measured early developmental behaviors (righting reflex, negative geotaxis), motor coordination, acoustic startle, short- and long-term activity, social behaviors, anxiety, and spatial learning and memory. DFMO treatment appeared to cause a decreased latency to perform the negative geotaxis behavior on PNDs 8-10 and increased latency to hang by the forelimbs on PNDs 12-14. Our previous study did not indicate similar effects, but age at testing differed between the two studies. DFMO treatment caused a decreased latency to maximum acoustic startle response in both the acoustic startle paradigm and in the pulse-alone trials of the prepulse inhibition test. This DFMO treatment paradigm induced a 10% decrease in adult cerebellar weight [Behav. Brain Res. 126 (2001) 135], but the results here imply that such developmental stunting has few functional alterations.

32-Bit-Wide Memory Tolerates Failures

NASA Technical Reports Server (NTRS)

Buskirk, Glenn A.

1990-01-01

Electronic memory system of 32-bit words corrects bit errors caused by some common type of failures - even failure of entire 4-bit-wide random-access-memory (RAM) chip. Detects failure of two such chips, so user warned that ouput of memory may contain errors. Includes eight 4-bit-wide DRAM's configured so each bit of each DRAM assigned to different one of four parallel 8-bit words. Each DRAM contributes only 1 bit to each 8-bit word.

[Effect of electroacupuncture intervention on learning-memory ability and injured hippocampal neurons in depression rats].

PubMed

Bao, Wu-Ye; Jiao, Shuang; Lu, Jun; Tu, Ya; Song, Ying-Zhou; Wu, Qian; A, Ying-Ge

2014-04-01

To observe the effect of electroacupuncture (EA) stimulation of "Baihui" (GV 20)-"Yintang" (EX-HN 3) on changes of learning-memory ability and hippocampal neuron structure in chronic stress-stimulation induced depression rats. Forty-eight SD rats were randomly divided into normal, model, EA and medication (Fluoxetine) groups, with 12 rats in each group. The depression model was established by chronic unpredictable mild stress stimulation (swimming in 4 degrees C water, fasting, water deprivation, reversed day and night, etc). Treatment was applied to "Baihui" (GV 20) and "Yintang" (EX-HN 3) for 20 min, once every day for 21 days. For rats of the medication group, Fluoxetine (3.3 mg/kg) was given by gavage (p.o.), once daily for 21 days. The learning-memory ability was detected by Morris water maze tests. The pathological and ultrastructural changes of the hippocampal tissue and neurons were assessed by H.E. staining, light microscope and transmission electron microscopy, respectively. Compared to the normal group, the rats' body weight on day 14 and day 21 after modeling was significantly decreased in the model group (P < 0.01), the escape latency and total swimming distance in the 4 quadrants on day 10 and 21 were significantly increased in the model group (P < 0.01). In comparison with the model group, the body weight on day 14 and 21 were significantly increased (P < 0.05), and the escape latency and total swimming distance levels were significantly decreased in the EA group (P < 0.01), suggesting an improvement of learning-memory ability. Observations of light microscope and transmission electron microscope showed that modeling induced pathological changes such as reduction in hippocampal cell layers, vague and broken cellular membrane, and ultrastructural changes of hippocampal neurons including swelling and reduction of mitochondria and mitochondrial crests were relived after EA and Fluoxetine treatment. EA intervention can improve the learning-memory ability and relieving impairment of hippocampal neurons in depression rats, which may be one of its mechanisms underlying bettering depression.

[Effects of quercetin on the learning and memory ability of neonatal rats with hypoxic-ischemic brain damage].

PubMed

Huang, Jing-Jing; Liu, Xuan; Wang, Xing-Qi; Yang, Li-Hua; Qi, Da-Shi; Yao, Rui-Qin

2012-06-01

To study the effects of quercetin, a flavonoid, on the learning and memory ability of 3-day-old neonatal rats with hypoxic-ischemic brain white matter damage (WMD). Sixty 3-day-old Sprague-Dawley rats were randomly divided into four groups: control, WMD model,and quercetin treatment groups (20 and 40 mg/kg). There were 15 rats in each group. Rats in the WMD model and the two quercetin treatment groups were subjected to right common carotid artery ligation followed by 2 hrs of exposure to 8% O2 to induce periventricular white matter injury. After the operation quercetin was administered daily in the two quercetin treatment groups for 6 weeks. Six weeks later, Morris water maze and open-field tests were carried out to test memory and learning ability as well as behavior and cognition. From the second day of training, escape latency in the Morris water maze test was more prolonged in the WMD model group than in the control group (P<0.01). The escape latency in the two quercetin treatment groups was shortened significantly compared with the WMD model group (P<0.05). The WMD model group crossed the original platform fewer times compared with the control and quercetin treatment groups (P<0.05). The open-field test indicated that the number of rearings increased and time spent in the centre was extended in the WMD model group compared with the control group. Compared with the WMD model group, the number of rearings was significantly reduced (P<0.05) and time spent in the centre was significantly shortened in the quercetin treatment groups (P<0.05). Quercetin treatment can improve memory and learning ability as well as cognitive ability in neonates with WMD, suggesting that quercetin protects against WMD resulting from hypoxia-ischemia.

A case-matched study of neurophysiological correlates to attention/working memory in people with somatic hypervigilance.

PubMed

Berryman, Carolyn; Wise, Vikki; Stanton, Tasha R; McFarlane, Alexander; Moseley, G Lorimer

2017-02-01

Somatic hypervigilance describes a clinical presentation in which people report more, and more intense, bodily sensations than is usual. Most explanations of somatic hypervigilance implicate altered information processing, but strong empirical data are lacking. Attention and working memory are critical for information processing, and we aimed to evaluate brain activity during attention/working memory tasks in people with and without somatic hypervigilance. Data from 173 people with somatic hypervigilance and 173 controls matched for age, gender, handedness, and years of education were analyzed. Event-related potential (ERP) data, extracted from the continuous electroencephalograph recordings obtained during performance of the Auditory Oddball task, and the Two In A Row (TIAR) task, for N1, P2, N2, and P3, were used in the analysis. Between-group differences for P3 amplitude and N2 amplitude and latency were assessed with two-tailed independent t tests. Between-group differences for N1 and P2 amplitude and latency were assessed using mixed, repeated measures analyses of variance (ANOVAs) with group and Group × Site factors. Linear regression analysis investigated the relationship between anxiety and depression and any outcomes of significance. People with somatic hypervigilance showed smaller P3 amplitudes-Auditory Oddball task: t(285) = 2.32, 95% confidence interval, CI [3.48, 4.47], p = .026, d = 0.27; Two-In-A-Row (TIAR) task: t(334) = 2.23, 95% CI [2.20; 3.95], p = .021, d = 0.24-than case-matched controls. N2 amplitude was also smaller in people with somatic hypervigilance-TIAR task: t(318) = 2.58, 95% CI [0.33, 2.47], p = .010, d = 0.29-than in case-matched controls. Neither depression nor anxiety was significantly associated with any outcome. People with somatic hypervigilance demonstrated an event-related potential response to attention/working memory tasks that is consistent with altered information processing.

Effect on intensity of treadmill running on learning, memory and expressions of cell cycle-related proteins in rats with cerebral ischemia.

PubMed

Zhao, Ya-Ning; Li, Jian-Min; Chen, Chang-Xiang; Li, Shu-Xing; Xue, Cheng-Jing

2017-06-20

We discussed the intensity of treadmill running on learning, memory and expression of cell cycle-related proteins in rats with cerebral ischemia. Eighty healthy male SD rats were randomly divided into normal group, model group, intensity I group and intensity II group, with 20 rats in each group. The four-vessel occlusion method of Pulsinelli (4-VO) was used to induce global cerebral ischemia. Brain neuronal morphology was observed by hematoxylin-eosin (HE) staining at 3h, 6h, 24h and 48h after modeling, respectively. Hippocampal expressions of cyclin A and cyclin E were detected by immunohistochemistry. At 48h after modeling, the learning and memory performance of rats was tested by water maze experiment. Compared with the normal group, the other three groups had a significant reduction in surviving neurons, prolonging of escape latency and decreased number of passes over the former position of the platform (P<0.05). The number of surviving neurons and the number of passes over the former position of the platform were obviously lower in the model group than in intensity I group (P<0.05), but significantly higher compared with intensity II group (P<0.05). Escape latency of the model group was obviously prolonged as compared with intensity I group (P<0.05), but much shorter than that of intensity II group (P<0.05). Compared with the normal group, the expressions of cyclin A and cyclin E were significantly upregulated at different time points after modeling (P<0.05). The expression of the model group was higher than that of intensity I group, but lower than that of intensity II group (P<0.05). Moderate intensity of treadmill running can help protect brain neurons and improve learning and memory performance of rats with global cerebral ischemia. But high intensity of treadmill running has a negative impact, possibly through the regulation of cell cycle-related proteins in ischemia/reperfusion injury.

Cannabigerol is a novel, well-tolerated appetite stimulant in pre-satiated rats.

PubMed

Brierley, Daniel I; Samuels, James; Duncan, Marnie; Whalley, Benjamin J; Williams, Claire M

2016-10-01

The appetite-stimulating properties of cannabis are well documented and have been predominantly attributed to the hyperphagic activity of the psychoactive phytocannabinoid, ∆(9)-tetrahydrocannabinol (∆(9)-THC). However, we have previously shown that a cannabis extract devoid of ∆(9)-THC still stimulates appetite, indicating that other phytocannabinoids also elicit hyperphagia. One possible candidate is the non-psychoactive phytocannabinoid cannabigerol (CBG), which has affinity for several molecular targets with known involvement in the regulation of feeding behaviour. The objective of the study was to assess the effects of CBG on food intake and feeding pattern microstructure. Male Lister hooded rats were administered CBG (30-120 mg/kg, per ora (p.o.)) or placebo and assessed in open field, static beam and grip strength tests to determine a neuromotor tolerability profile for this cannabinoid. Subsequently, CBG (at 30-240 mg/kg, p.o.) or placebo was administered to a further group of pre-satiated rats, and hourly intake and meal pattern data were recorded over 2 h. CBG produced no adverse effects on any parameter in the neuromotor tolerability test battery. In the feeding assay, 120-240 mg/kg CBG more than doubled total food intake and increased the number of meals consumed, and at 240 mg/kg reduced latency to feed. However, the sizes or durations of individual meals were not significantly increased. Here, we demonstrate for the first time that CBG elicits hyperphagia, by reducing latency to feed and increasing meal frequency, without producing negative neuromotor side effects. Investigation of the therapeutic potential of CBG for conditions such as cachexia and other disorders of eating and body weight regulation is thus warranted.

Fault tolerant computing: A preamble for assuring viability of large computer systems

NASA Technical Reports Server (NTRS)

Lim, R. S.

1977-01-01

The need for fault-tolerant computing is addressed from the viewpoints of (1) why it is needed, (2) how to apply it in the current state of technology, and (3) what it means in the context of the Phoenix computer system and other related systems. To this end, the value of concurrent error detection and correction is described. User protection, program retry, and repair are among the factors considered. The technology of algebraic codes to protect memory systems and arithmetic codes to protect memory systems and arithmetic codes to protect arithmetic operations is discussed.

Direct non-productive HIV-1 infection in a T-cell line is driven by cellular activation state and NFκB

PubMed Central

2014-01-01

Background Molecular latency allows HIV-1 to persist in resting memory CD4+ T-cells as transcriptionally silent provirus integrated into host chromosomal DNA. Multiple transcriptional regulatory mechanisms for HIV-1 latency have been described in the context of progressive epigenetic silencing and maintenance. However, our understanding of the determinants critical for the establishment of latency in newly infected cells is limited. Results In this study, we used a recently described, doubly fluorescent HIV-1 latency model to dissect the role of proviral integration sites and cellular activation state on direct non-productive infections at the single cell level. Proviral integration site mapping of infected Jurkat T-cells revealed that productively and non-productively infected cells are indistinguishable in terms of genomic landmarks, surrounding epigenetic landscapes, and proviral orientation relative to host genes. However, direct non-productive infections were inversely correlated with both cellular activation state and NFκB activity. Furthermore, modulating NFκB with either small molecules or by conditional overexpression of NFκB subunits was sufficient to alter the propensity of HIV-1 to directly enter a non-productive latent state in newly infected cells. Importantly, this modulatory effect was limited to a short time window post-infection. Conclusions Taken together, our data suggest that cellular activation state and NFκB activity during the time of infection, but not the site of proviral integration, are important regulators of direct HIV-1 non-productive infections. PMID:24502247

JPEG XS, a new standard for visually lossless low-latency lightweight image compression

NASA Astrophysics Data System (ADS)

Descampe, Antonin; Keinert, Joachim; Richter, Thomas; Fößel, Siegfried; Rouvroy, Gaël.

2017-09-01

JPEG XS is an upcoming standard from the JPEG Committee (formally known as ISO/IEC SC29 WG1). It aims to provide an interoperable visually lossless low-latency lightweight codec for a wide range of applications including mezzanine compression in broadcast and Pro-AV markets. This requires optimal support of a wide range of implementation technologies such as FPGAs, CPUs and GPUs. Targeted use cases are professional video links, IP transport, Ethernet transport, real-time video storage, video memory buffers, and omnidirectional video capture and rendering. In addition to the evaluation of the visual transparency of the selected technologies, a detailed analysis of the hardware and software complexity as well as the latency has been done to make sure that the new codec meets the requirements of the above-mentioned use cases. In particular, the end-to-end latency has been constrained to a maximum of 32 lines. Concerning the hardware complexity, neither encoder nor decoder should require more than 50% of an FPGA similar to Xilinx Artix 7 or 25% of an FPGA similar to Altera Cyclon 5. This process resulted in a coding scheme made of an optional color transform, a wavelet transform, the entropy coding of the highest magnitude level of groups of coefficients, and the raw inclusion of the truncated wavelet coefficients. This paper presents the details and status of the standardization process, a technical description of the future standard, and the latest performance evaluation results.

A 1-Gigabit Memory System on a multi-Chip Module for Space Applications

NASA Technical Reports Server (NTRS)

Louie, Marianne E.; Topliffe, Douglas A.; Alkalai, Leon

1996-01-01

Current spaceborne applications desire compact, low weight, and high capacity data storage systems along with the additional requirement of radiation tolerance. This paper discusses a memory system on a multi-chip module (MCM) that is designed for space applications.

Objective but not subjective sleep predicts memory in community-dwelling older adults.

PubMed

Cavuoto, Marina G; Ong, Ben; Pike, Kerryn E; Nicholas, Christian L; Bei, Bei; Kinsella, Glynda J

2016-08-01

Research on the relationship between habitual sleep patterns and memory performance in older adults is limited. No previous study has used objective and subjective memory measures in a large, older-aged sample to examine the association between sleep and various domains of memory. The aim of this study was to examine the association between objective and subjective measures of sleep with memory performance in older adults, controlling for the effects of potential confounds. One-hundred and seventy-three community-dwelling older adults aged 65-89 years in Victoria, Australia completed the study. Objective sleep quality and length were ascertained using the Actiwatch 2 Mini-Mitter, while subjective sleep was measured using the Pittsburgh Sleep Quality Index. Memory was indexed by tests of retrospective memory (Hopkins Verbal Learning Test - Revised), working memory (n-back, 2-back accuracy) and prospective memory (a habitual button pressing task). Compared with normative data, overall performance on retrospective memory function was within the average range. Hierarchical regression was used to determine whether objective or subjective measures of sleep predicted memory performances after controlling for demographics, health and mood. After controlling for confounds, actigraphic sleep indices (greater wake after sleep onset, longer sleep-onset latency and longer total sleep time) predicted poorer retrospective (∆R(2)  = 0.05, P = 0.016) and working memory (∆R(2)  = 0.05, P = 0.047). In contrast, subjective sleep indices did not significantly predict memory performances. In community-based older adults, objectively-measured, habitual sleep indices predict poorer memory performances. It will be important to follow the sample longitudinally to determine trajectories of change over time. © 2016 European Sleep Research Society.

Dynamic storage in resource-scarce browsing multimedia applications

NASA Astrophysics Data System (ADS)

Elenbaas, Herman; Dimitrova, Nevenka

1998-10-01

In the convergence of information and entertainment there is a conflict between the consumer's expectation of fast access to high quality multimedia content through narrow bandwidth channels versus the size of this content. During the retrieval and information presentation of a multimedia application there are two problems that have to be solved: the limited bandwidth during transmission of the retrieved multimedia content and the limited memory for temporary caching. In this paper we propose an approach for latency optimization in information browsing applications. We proposed a method for flattening hierarchically linked documents in a manner convenient for network transport over slow channels to minimize browsing latency. Flattening of the hierarchy involves linearization, compression and bundling of the document nodes. After the transfer, the compressed hierarchy is stored on a local device where it can be partly unbundled to fit the caching limits at the local site while giving the user availability to the content.

A model that integrates eye velocity commands to keep track of smooth eye displacements.

PubMed

Blohm, Gunnar; Optican, Lance M; Lefèvre, Philippe

2006-08-01

Past results have reported conflicting findings on the oculomotor system's ability to keep track of smooth eye movements in darkness. Whereas some results indicate that saccades cannot compensate for smooth eye displacements, others report that memory-guided saccades during smooth pursuit are spatially correct. Recently, it was shown that the amount of time before the saccade made a difference: short-latency saccades were retinotopically coded, whereas long-latency saccades were spatially coded. Here, we propose a model of the saccadic system that can explain the available experimental data. The novel part of this model consists of a delayed integration of efferent smooth eye velocity commands. Two alternative physiologically realistic neural mechanisms for this integration stage are proposed. Model simulations accurately reproduced prior findings. Thus, this model reconciles the earlier contradictory reports from the literature about compensation for smooth eye movements before saccades because it involves a slow integration process.

Agreement processing and attraction errors in aging: evidence from subject-verb agreement in German.

PubMed

Reifegerste, Jana; Hauer, Franziska; Felser, Claudia

2017-11-01

Effects of aging on lexical processing are well attested, but the picture is less clear for grammatical processing. Where age differences emerge, these are usually ascribed to working-memory (WM) decline. Previous studies on the influence of WM on agreement computation have yielded inconclusive results, and work on aging and subject-verb agreement processing is lacking. In two experiments (Experiment 1: timed grammaticality judgment, Experiment 2: self-paced reading + WM test), we investigated older (OA) and younger (YA) adults' susceptibility to agreement attraction errors. We found longer reading latencies and judgment reaction times (RTs) for OAs. Further, OAs, particularly those with low WM scores, were more accepting of sentences with attraction errors than YAs. OAs showed longer reading latencies for ungrammatical sentences, again modulated by WM, than YAs. Our results indicate that OAs have greater difficulty blocking intervening nouns from interfering with the computation of agreement dependencies. WM can modulate this effect.

Impact of adolescent alcohol use across the lifespan: Long-lasting tolerance to high-dose alcohol coupled with potentiated spatial memory impairments to moderate-dose alcohol.

PubMed

Matthews, Douglas B; Novier, Adelle; Diaz-Granados, Jaime L; Van Skike, Candice E; Ornelas, Laura; Mittleman, G

2017-06-01

Understanding how alcohol exposure during adolescence affects aging is a critical but understudied area. In the present study, male rats were exposed to either alcohol or saline during adolescence, then tested every 4 months following either an ethanol or saline challenge; animals were tested until postnatal day (PD) 532. It was found that long-lasting tolerance to high-dose ethanol exists through the test period, as measured by loss of righting reflex, while tolerance to lower doses of ethanol is not found. In addition, alcohol exposure during adolescence facilitated spatial memory impairments to acute ethanol challenges later in life. The current work demonstrates that exposure to ethanol during adolescent development can produce long-lasting detrimental impairments. Copyright © 2017 Elsevier Inc. All rights reserved.

Enhanced polychronization in a spiking network with metaplasticity.

PubMed

Guise, Mira; Knott, Alistair; Benuskova, Lubica

2015-01-01

Computational models of metaplasticity have usually focused on the modeling of single synapses (Shouval et al., 2002). In this paper we study the effect of metaplasticity on network behavior. Our guiding assumption is that the primary purpose of metaplasticity is to regulate synaptic plasticity, by increasing it when input is low and decreasing it when input is high. For our experiments we adopt a model of metaplasticity that demonstrably has this effect for a single synapse; our primary interest is in how metaplasticity thus defined affects network-level phenomena. We focus on a network-level phenomenon called polychronicity, that has a potential role in representation and memory. A network with polychronicity has the ability to produce non-synchronous but precisely timed sequences of neural firing events that can arise from strongly connected groups of neurons called polychronous neural groups (Izhikevich et al., 2004). Polychronous groups (PNGs) develop readily when spiking networks are exposed to repeated spatio-temporal stimuli under the influence of spike-timing-dependent plasticity (STDP), but are sensitive to changes in synaptic weight distribution. We use a technique we have recently developed called Response Fingerprinting to show that PNGs formed in the presence of metaplasticity are significantly larger than those with no metaplasticity. A potential mechanism for this enhancement is proposed that links an inherent property of integrator type neurons called spike latency to an increase in the tolerance of PNG neurons to jitter in their inputs.

PASS assisted prediction and pharmacological evaluation of novel nicotinic analogs for nootropic activity in mice.

PubMed

Khurana, Navneet; Ishar, Mohan Pal Singh; Gajbhiye, Asmita; Goel, Rajesh Kumar

2011-07-15

The aim of present study is to predict the probable nootropic activity of novel nicotine analogues with the help of computer program, PASS (prediction of activity spectra for substances) and evaluate the same. Two compounds from differently substituted pyridines were selected for synthesis and evaluation of nootropic activity based on their high probable activity (Pa) value predicted by PASS computer program. Evaluation of nootropic activity of compounds after acute and chronic treatment was done with transfer latency (TL) and step down latency (SDL) methods which showed significant nootropic activity. The effect on scopolamine induced amnesia was also observed along with their acetylcholine esterase inhibitory activity which also showed positive results which strengthened their efficacy as nootropic agents through involvement of cholinergic system. This nootropic effect was similar to the effect of nicotine and donepezil used as standard drugs. Muscle coordination and locomotor activity along with their addiction liability, safety and tolerability studies were also evaluated. These studies showed that these compounds are well tolerable and safe over a wide range of doses tested along with the absence of withdrawal effect which is present in nicotine due to its addiction liability. The study showed that these compounds are true nicotine analogs with desirable efficacy and safety profile for their use as effective nootropic agents. Copyright © 2011 Elsevier B.V. All rights reserved.

Implicit memory for novel figure-ground displays includes a history of cross-border competition.

PubMed

Peterson, Mary A; Lampignano, Daniel W

2003-08-01

When configural cues specify that a figure lies on opposite sides of a repeated border in prime andprobe shapes, probe latencies are longer than when prime and probe borders are unrelated. Do such results reflect negative priming for the shape of the prime ground or cross-border competition from figure memory? The present study tested these alternatives by adding partial closure as a competing cue and reducing the similarity between the prime ground and the shape of the probe. Results supported the cross-border competition interpretation. Additional findings were that partial closure is a configural cue and that response effects can emerge from the potential shape on the ground side of a border. One prior experience was sufficient for these effects.

Are event-related potentials to dynamic facial expressions of emotion related to individual differences in the accuracy of processing facial expressions and identity?

PubMed

Recio, Guillermo; Wilhelm, Oliver; Sommer, Werner; Hildebrandt, Andrea

2017-04-01

Despite a wealth of knowledge about the neural mechanisms behind emotional facial expression processing, little is known about how they relate to individual differences in social cognition abilities. We studied individual differences in the event-related potentials (ERPs) elicited by dynamic facial expressions. First, we assessed the latent structure of the ERPs, reflecting structural face processing in the N170, and the allocation of processing resources and reflexive attention to emotionally salient stimuli, in the early posterior negativity (EPN) and the late positive complex (LPC). Then we estimated brain-behavior relationships between the ERP factors and behavioral indicators of facial identity and emotion-processing abilities. Structural models revealed that the participants who formed faster structural representations of neutral faces (i.e., shorter N170 latencies) performed better at face perception (r = -.51) and memory (r = -.42). The N170 amplitude was not related to individual differences in face cognition or emotion processing. The latent EPN factor correlated with emotion perception (r = .47) and memory (r = .32), and also with face perception abilities (r = .41). Interestingly, the latent factor representing the difference in EPN amplitudes between the two neutral control conditions (chewing and blinking movements) also correlated with emotion perception (r = .51), highlighting the importance of tracking facial changes in the perception of emotional facial expressions. The LPC factor for negative expressions correlated with the memory for emotional facial expressions. The links revealed between the latency and strength of activations of brain systems and individual differences in processing socio-emotional information provide new insights into the brain mechanisms involved in social communication.

Effects of developmental exposure to bisphenol A on spatial navigational learning and memory in rats: A CLARITY-BPA study.

PubMed

Johnson, Sarah A; Javurek, Angela B; Painter, Michele S; Ellersieck, Mark R; Welsh, Thomas H; Camacho, Luísa; Lewis, Sherry M; Vanlandingham, Michelle M; Ferguson, Sherry A; Rosenfeld, Cheryl S

2016-04-01

Bisphenol A (BPA) is a ubiquitous industrial chemical used in the production of a wide variety of items. Previous studies suggest BPA exposure may result in neuro-disruptive effects; however, data are inconsistent across animal and human studies. As part of the Consortium Linking Academic and Regulatory Insights on BPA Toxicity (CLARITY-BPA), we sought to determine whether female and male rats developmentally exposed to BPA demonstrated later spatial navigational learning and memory deficits. Pregnant NCTR Sprague-Dawley rats were orally dosed from gestational day 6 to parturition, and offspring were directly orally dosed until weaning (postnatal day 21). Treatment groups included a vehicle control, three BPA doses (2.5μg/kg body weight (bw)/day-[2.5], 25μg/kg bw/day-[25], and 2500μg/kg bw/day-[2500]) and a 0.5μg/kg/day ethinyl estradiol (EE)-reference estrogen dose. At adulthood, 1/sex/litter was tested for seven days in the Barnes maze. The 2500 BPA group sniffed more incorrect holes on day 7 than those in the control, 2.5 BPA, and EE groups. The 2500 BPA females were less likely than control females to locate the escape box in the allotted time (p value=0.04). Although 2.5 BPA females exhibited a prolonged latency, the effect did not reach significance (p value=0.06), whereas 2.5 BPA males showed improved latency compared to control males (p value=0.04), although the significance of this result is uncertain. No differences in serum testosterone concentration were detected in any male or female treatment groups. Current findings suggest developmental exposure of rats to BPA may disrupt aspects of spatial navigational learning and memory. Copyright © 2015 Elsevier Inc. All rights reserved.

Increased risk of developing schizophrenia in animals exposed to cigarette smoke during the gestational period.

PubMed

Zugno, Alexandra I; Oliveira, Mariana B; Mastella, Gustavo A; Heylmann, Alexandra S A; Canever, Lara; Pacheco, Felipe D; Damazio, Louyse S; Citadin, Sullivan A; de Lucca, Luiz Antonio; Simões, Lutiana Roque; Malgarin, Fernanda; Budni, Josiane; Barichello, Tatiana; Schuck, Patricia F; Quevedo, João

2017-04-03

Cigarette smoking during the prenatal period has been investigated as a causative factor of obstetric abnormalities, which lead to cognitive and behavioural changes associated with schizophrenia. The aim of this study was to investigate behaviour and AChE activity in brain structures in adult rats exposed to cigarette smoke during the prenatal period. Pregnant rats were divided into non-PCSE (non-prenatal cigarette smoke exposure) and PCSE (prenatal cigarette smoke exposure) groups. On post-natal day 60, the rats received saline or ketamine for 7days and were subjected to behavioural tasks. In the locomotor activity task, the non-PCSE+ketamine and PCSE+ketamine groups exhibited increased locomotor activity compared with the saline group. In the social interaction task, the non-PCSE+ketamine and PCSE+ketamine groups exhibited an increased latency compared with the control groups. However, the PCSE+ketamine group exhibited a decreased latency compared with the non-PCSE+ketamine group, which indicates that the cigarette exposure appeared to decrease, the social deficits generated by ketamine. In the inhibitory avoidance task, the non-PCSE+ketamine, PCSE, and PCSE+ketamine groups exhibited impairments in working memory, short-term memory, and long-term memory. In the pre-pulse inhibition (PPI) test, cigarette smoke associated with ketamine resulted in impaired PPI in 3 pre-pulse (PP) intensity groups compared with the control groups. In the biochemical analysis, the AChE activity in brain structures increased in the ketamine groups; however, the PCSE+ketamine group exhibited an exacerbated effect in all brain structures. The present study indicates that exposure to cigarette smoke during the prenatal period may affect behaviour and cerebral cholinergic structures during adulthood. Copyright © 2017 Elsevier Inc. All rights reserved.

Effects of Developmental Exposure to Bisphenol A on Spatial Navigational Learning and Memory in Rats: A CLARITY-BPA Study

PubMed Central

Johnson, Sarah A.; Javurek, Angela B.; Painter, Michele S.; Ellersieck, Mark R.; Welsh, Thomas H.; Camacho, Luísa; Lewis, Sherry M.; Vanlandingham, Michelle M.; Ferguson, Sherry A.; Rosenfeld, Cheryl S.

2015-01-01

Bisphenol A (BPA) is a ubiquitous industrial chemical used in the production of a wide variety of items. Previous studies suggest BPA exposure may result in neuro-disruptive effects; however, data are inconsistent across animal and human studies. As part of the Consortium Linking Academic and Regulatory Insights on BPA Toxicity (CLARITY-BPA), we sought to determine whether female and male rats developmentally exposed to BPA demonstrated later spatial navigational learning and memory deficits. Pregnant NCTR Sprague-Dawley rats were orally dosed from gestational day 6 to parturition, and offspring were directly orally dosed until weaning (postnatal day 21). Treatment groups included a vehicle control, three BPA doses (2.5 μg/kg/day-[2.5], 25 μg/kg/day-[25], and 2500 μg/kg/day-[2500]) and a 0.5 μg/kg/day ethinyl estradiol (EE)-reference estrogen dose. At adulthood, 1/sex/litter was tested for seven days in the Barnes maze. The 2500 BPA group sniffed more incorrect holes on day 7 than those in the control, 2.5 BPA, and EE groups. The 2500 BPA females were less likely than control females to locate the escape box in the allotted time (P value= 0.04). Although 2.5 BPA females exhibited a prolonged latency, the effect did not reach significance (P value = 0.06), whereas 2.5 BPA males showed improved latency compared to control males (P value = 0.04), although the significance of this result is uncertain. No differences in serum testosterone concentration were detected in any male or female treatment groups. Current findings suggest developmental exposure of rats to BPA may disrupt aspects of spatial navigational learning and memory. PMID:26436835

Repeated stressor exposure enhances contextual fear memory in a beta-adrenergic receptor-dependent process and increases impulsivity in a non-beta receptor-dependent fashion.

PubMed

Camp, Robert M; Johnson, John D

2015-10-15

Memory formation is promoted by stress via the release of norepinephrine and stimulation of beta-adrenergic receptors (β-ARs). Previous data demonstrate that repeated stressor exposure increases norepinephrine turnover and β-AR signaling within the amygdala, which led to the hypothesis that some stress-induced behavioral changes are likely due to facilitated associative learning. To test this, Fischer rats were exposed to chronic mild stress for four days. On day 5, subjects (including non-stressed controls) were injected with the beta-blocker propranolol or vehicle prior to conditioning in an operant box (animals receive two mild foot shocks) or passive avoidance apparatus (animals received a foot shock upon entry into the dark chamber). Twenty-four hours later, subjects were returned to the operant box for measurement of freezing or returned to the passive avoidance apparatus for measurement of latency to enter the dark chamber. Subjects were also tested in an open field to assess context-independent anxiety-like behavior. Animals exposed to chronic stress showed significantly more freezing behavior in the operant box than did controls, and this exaggerated freezing was blocked by propranolol during the conditioning trial. There was no effect of stress on behavior in the open field. Unexpectedly, retention latency was significantly reduced in subjects exposed to chronic stress. These results indicate that chronic exposure to stress results in complex behavioral changes. While repeated stress appears to enhance the formation of fearful memories, it also results in behavioral responses that resemble impulsive behaviors that result in poor decision-making. Copyright © 2015 Elsevier Inc. All rights reserved.

Flammulina velutipes polysaccharides improve scopolamine-induced learning and memory impairment in mice by modulating gut microbiota composition.

PubMed

Su, Anxiang; Yang, Wenjian; Zhao, Liyan; Pei, Fei; Yuan, Biao; Zhong, Lei; Ma, Gaoxing; Hu, Qiuhui

2018-03-01

Flammulina velutipes polysaccharides (FVP) have been proved to be effective in improving learning and memory impairment in mice. However, their underlying mechanism remains unclear. The aim of this study was to investigate the relationship between memory improvement and gut microbiota regulation of FVP. The results showed a significant decrease in the relative abundances of Clostridia and Bacilli but a significant increase in Bacteroidia, Erysipelotrichia and Actinobacteria in the FVP-treated group versus the control group. Fecal microbiota transplantation of mice with 'FVP microbiota' derived from FVP-fed mice resulted in improved learning and memory function compared to colonization with 'common microbiota' derived from control individuals. FVP and 'FVP microbiota' significantly increased the numbers of platform crossings and the swimming distance of mice in the probe test and decreased the escape latency and total swimming distance of mice in the hidden platform test. Moreover, FVP and 'FVP microbiota' regulated cytokines, such as IL-1β, TNF-α, IL-6 and IL-10, suggesting a mechanism involving the suppression of neuroinflammation. This study indicated that the regulation of the gut microbiome may have a causal role in improving scopolamine-induced impairment of learning and memory.

Cognitive load during route selection increases reliance on spatial heuristics.

PubMed

Brunyé, Tad T; Martis, Shaina B; Taylor, Holly A

2018-05-01

Planning routes from maps involves perceiving the symbolic environment, identifying alternate routes and applying explicit strategies and implicit heuristics to select an option. Two implicit heuristics have received considerable attention, the southern route preference and initial segment strategy. This study tested a prediction from decision-making theory that increasing cognitive load during route planning will increase reliance on these heuristics. In two experiments, participants planned routes while under conditions of minimal (0-back) or high (2-back) working memory load. In Experiment 1, we examined how memory load impacts the southern route heuristic. In Experiment 2, we examined how memory load impacts the initial segment heuristic. Results replicated earlier results demonstrating a southern route preference (Experiment 1) and initial segment strategy (Experiment 2) and further demonstrated that evidence for heuristic reliance is more likely under conditions of concurrent working memory load. Furthermore, the extent to which participants maintained efficient route selection latencies in the 2-back condition predicted the magnitude of this effect. Together, results demonstrate that working memory load increases the application of heuristics during spatial decision making, particularly when participants attempt to maintain quick decisions while managing concurrent task demands.

The impairment of learning and memory and synaptic loss in mouse after chronic nitrite exposure.

PubMed

Chen, Yongfang; Cui, Zhanjun; Wang, Lai; Liu, Hongliang; Fan, Wenjuan; Deng, Jinbo; Deng, Jiexin

2016-12-01

The objective of this study is to understand the impairment of learning and memory in mouse after chronic nitrite exposure. The animal model of nitrite exposure in mouse was created with the daily intubation of nitrite in adult healthy male mice for 3 months. Furthermore, the mouse's learning and memory abilities were tested with Morris water maze, and the expression of Synaptophysin and γ-Synuclein was visualized with immunocytochemistry and Western blot. Our results showed that nitrite exposure significantly prolonged the escape latency period (ELP) and decreased the values of the frequency across platform (FAP) as well as the accumulative time in target quadrant (ATITQ) compared to control, in dose-dependent manner. In addition, after nitrite exposure, synaptophysin (SYN) positive buttons in the visual cortex was reduced, in contrast the increase of γ-synuclein positive cells. The results above were supported by Western blot as well. We conclude that nitrite exposure could lead to a decline in mice's learning and memory. The overexpression of γ-synuclein contributed to the synaptic loss, which is most likely the cause of learning and memory impairment. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 1720-1730, 2016. © 2015 Wiley Periodicals, Inc.

CUDA Optimization Strategies for Compute- and Memory-Bound Neuroimaging Algorithms

PubMed Central

Lee, Daren; Dinov, Ivo; Dong, Bin; Gutman, Boris; Yanovsky, Igor; Toga, Arthur W.

2011-01-01

As neuroimaging algorithms and technology continue to grow faster than CPU performance in complexity and image resolution, data-parallel computing methods will be increasingly important. The high performance, data-parallel architecture of modern graphical processing units (GPUs) can reduce computational times by orders of magnitude. However, its massively threaded architecture introduces challenges when GPU resources are exceeded. This paper presents optimization strategies for compute- and memory-bound algorithms for the CUDA architecture. For compute-bound algorithms, the registers are reduced through variable reuse via shared memory and the data throughput is increased through heavier thread workloads and maximizing the thread configuration for a single thread block per multiprocessor. For memory-bound algorithms, fitting the data into the fast but limited GPU resources is achieved through reorganizing the data into self-contained structures and employing a multi-pass approach. Memory latencies are reduced by selecting memory resources whose cache performance are optimized for the algorithm's access patterns. We demonstrate the strategies on two computationally expensive algorithms and achieve optimized GPU implementations that perform up to 6× faster than unoptimized ones. Compared to CPU implementations, we achieve peak GPU speedups of 129× for the 3D unbiased nonlinear image registration technique and 93× for the non-local means surface denoising algorithm. PMID:21159404

Extract from Fructus cannabis activating calcineurin improved learning and memory in mice with chemical drug-induced dysmnesia.

PubMed

Luo, Jing; Yin, Jiang-Hua; Wu, He-Zhen; Wei, Qun

2003-11-01

To investigate the effects of extract from Fructus cannabis (EFC) that can activate calcineurin on learning and memory impairment induced by chemical drugs in mice. Bovine brain calcineurin and calmodulin were isolated from frozen tissues. The activity of calcineurin was assayed using p-nitrophenyl phosphate (PNPP) as the substrate. Step-down type passive avoidance test and water maze were used together to determine the effects of EFC on learning and memory dysfunction. EFC activated calcineurin activity at a concentration range of 0.01-100 g/L. The maximal value of EFC on calcineurin activity (35 %+/-5 %) appeared at a concentration of 10 g/L. The chemical drugs such as scopolamine, sodium nitrite, and 45 % ethanol, and sodium pentobarbital induced learning and memory dysfunction. EFC administration (0.2, 0.4, and 0.8 g/kg, igx7 d) prolonged the latency and decreased the number of errors in the step-down test. EFC, given for 7 d, enhanced the spatial resolution of amnesic mice in water maze test. EFC overcome amnesia of three stages of memory process at the dose of 0.2 g/kg. EFC with an activation role of calcineurin can improve the impaired learning and memory induced by chemical drugs in mice.

The effect of the steroid sulfatase inhibitor (p-O-sulfamoyl)-tetradecanoyl tyramine (DU-14) on learning and memory in rats with selective lesion of septal-hippocampal cholinergic tract.

PubMed

Babalola, P A; Fitz, N F; Gibbs, R B; Flaherty, P T; Li, P-K; Johnson, D A

2012-10-01

Dehydroepiandrosterone sulfate (DHEAS), is an excitatory neurosteroid synthesized within the CNS that modulates brain function. Effects associated with augmented DHEAS include learning and memory enhancement. Inhibitors of the steroid sulfatase enzyme increase brain DHEAS levels and can also facilitate learning and memory. This study investigated the effect of steroid sulfatase inhibition on learning and memory in rats with selective cholinergic lesion of the septo-hippocampal tract using passive avoidance and delayed matching to position T-maze (DMP) paradigms. The selective cholinergic immunotoxin 192 IgG-saporin (SAP) was infused into the medial septum of animals and then tested using a step-through passive avoidance paradigm or DMP paradigm. Peripheral administration of the steroid sulfatase inhibitor, DU-14, increased step-through latency following footshock in rats with SAP lesion compared to both vehicle treated control and lesioned animals (p<0.05). However, in the DMP task, steroid sulfatase inhibition impaired acquisition in lesioned rats while having no effect on intact animals. These results suggest that steroid sulfatase inhibition facilitates memory associated with contextual fear, but impairs acquisition of spatial memory tasks in rats with selective lesion of the septo-hippocampal tract. Copyright © 2012 Elsevier Inc. All rights reserved.

CUDA optimization strategies for compute- and memory-bound neuroimaging algorithms.

PubMed

Lee, Daren; Dinov, Ivo; Dong, Bin; Gutman, Boris; Yanovsky, Igor; Toga, Arthur W

2012-06-01

As neuroimaging algorithms and technology continue to grow faster than CPU performance in complexity and image resolution, data-parallel computing methods will be increasingly important. The high performance, data-parallel architecture of modern graphical processing units (GPUs) can reduce computational times by orders of magnitude. However, its massively threaded architecture introduces challenges when GPU resources are exceeded. This paper presents optimization strategies for compute- and memory-bound algorithms for the CUDA architecture. For compute-bound algorithms, the registers are reduced through variable reuse via shared memory and the data throughput is increased through heavier thread workloads and maximizing the thread configuration for a single thread block per multiprocessor. For memory-bound algorithms, fitting the data into the fast but limited GPU resources is achieved through reorganizing the data into self-contained structures and employing a multi-pass approach. Memory latencies are reduced by selecting memory resources whose cache performance are optimized for the algorithm's access patterns. We demonstrate the strategies on two computationally expensive algorithms and achieve optimized GPU implementations that perform up to 6× faster than unoptimized ones. Compared to CPU implementations, we achieve peak GPU speedups of 129× for the 3D unbiased nonlinear image registration technique and 93× for the non-local means surface denoising algorithm. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

Sex differences in tool use acquisition in bonobos (Pan paniscus).

PubMed

Boose, Klaree J; White, Frances J; Meinelt, Audra

2013-09-01

All the great ape species are known tool users in both the wild and captivity, although there is great variation in ability and behavioral repertoire. Differences in tool use acquisition between chimpanzees and gorillas have been attributed to differing levels of social tolerance as a result of differences in social structure. Chimpanzees also show sex differences in acquisition and both chimpanzees and bonobos demonstrate a female bias in tool use behaviors. Studies of acquisition are limited in the wild and between species comparisons are complicated in captivity by contexts that often do not reflect natural conditions. Here we investigated tool use acquisition in a captive group of naïve bonobos by simulating naturalistic conditions. We constructed an artificial termite mound fashioned after those that occur in the wild and tested individuals within a social group context. We found sex differences in latencies to attempt and to succeed where females attempted to fish, were successful more quickly, and fished more frequently than males. We compared our results to those reported for chimpanzees and gorillas. Males across all three species did not differ in latency to attempt or to succeed. In contrast, bonobo and chimpanzee females succeeded more quickly than did female gorillas. Female bonobos and female chimpanzees did not differ in either latency to attempt or to succeed. We tested the social tolerance hypothesis by investigating the relationship between tool behaviors and number of neighbors present. We also compared these results to those reported for chimpanzees and gorillas and found that bonobos had the fewest numbers of neighbors present. The results of this study do not support the association between number of neighbors and tool behavior reported for chimpanzees. However, bonobos demonstrated a similar sex difference in tool use acquisition, supporting the hypothesis of a female bias in tool use in Pan. © 2013 Wiley Periodicals, Inc.

Post-encoding control of working memory enhances processing of relevant information in rhesus monkeys (Macaca mulatta).

PubMed

Brady, Ryan J; Hampton, Robert R

2018-06-01

Working memory is a system by which a limited amount of information can be kept available for processing after the cessation of sensory input. Because working memory resources are limited, it is adaptive to focus processing on the most relevant information. We used a retro-cue paradigm to determine the extent to which monkey working memory possesses control mechanisms that focus processing on the most relevant representations. Monkeys saw a sample array of images, and shortly after the array disappeared, they were visually cued to a location that had been occupied by one of the sample images. The cue indicated which image should be remembered for the upcoming recognition test. By determining whether the monkeys were more accurate and quicker to respond to cued images compared to un-cued images, we tested the hypothesis that monkey working memory focuses processing on relevant information. We found a memory benefit for the cued image in terms of accuracy and retrieval speed with a memory load of two images. With a memory load of three images, we found a benefit in retrieval speed but only after shortening the onset latency of the retro-cue. Our results demonstrate previously unknown flexibility in the cognitive control of memory in monkeys, suggesting that control mechanisms in working memory likely evolved in a common ancestor of humans and monkeys more than 32 million years ago. Future work should be aimed at understanding the interaction between memory load and the ability to control memory resources, and the role of working memory control in generating differences in cognitive capacity among primates. Copyright © 2018 Elsevier B.V. All rights reserved.

Effect of Royal Jelly on spatial learning and memory in rat model of streptozotocin-induced sporadic Alzheimer's disease

PubMed Central

Zamani, Zohre; Reisi, Parham; Alaei, Hojjatallah; Pilehvarian, Ali Asghar

2012-01-01

Background: It has been recently demonstrated that Royal jelly (RJ) has a beneficial role on neural functions. Alzheimer's disease (AD) is associated with impairments of learning and memory. Therefore, the present study was designed to examine the effect of RJ on spatial learning and memory in rats after intracerebroventricular injection of streptozotocin (icv-STZ). Materials and Methods: Rats were infused bilaterally with an icv injection of STZ, while sham rats received vehicle only. The rats were feed with RJ-contained food (3% w/w) (lyophilized RJ mixed with powdered regular food) or regular food for 10 days. Then spatial learning and memory was tested in the rats by Morris water maze test. Results: Results showed that in icv-STZ group latency and path length were increased as compared to sham group, also icv-STZ rats less remembered the target quadrant that previously the platform was located; however, these were protected significantly in STZ group that received RJ-containing food. Conclusions: Our findings support the potential neuroprotective role of RJ and its helpful effects in AD. PMID:23210085

Associations between a neurophysiological marker of central cholinergic activity and cognitive functions in young and older adults

PubMed Central

2012-01-01

Background The deterioration of the central cholinergic system in aging is hypothesized to underlie declines in several cognitive domains, including memory and executive functions. However, there is surprisingly little direct evidence regarding acetylcholine’s specific role(s) in normal human cognitive aging. Methods We used short-latency afferent inhibition (SAI) with transcranial magnetic stimulation (TMS) as a putative marker of cholinergic activity in vivo in young (n = 24) and older adults (n = 31). Results We found a significant age difference in SAI, concordant with other evidence of cholinergic decline in normal aging. We also found clear age differences on several of the memory and one of the executive function measures. Individual differences in SAI levels predicted memory but not executive functions. Conclusion Individual differences in SAI levels were better predictors of memory than executive functions. We discuss cases in which the relations between SAI and cognition might be even stronger, and refer to other age-related biological changes that may interact with cholinergic activity in cognitive aging. PMID:22537877

The Comparison of Visual Working Memory Representations with Perceptual Inputs

PubMed Central

Hyun, Joo-seok; Woodman, Geoffrey F.; Vogel, Edward K.; Hollingworth, Andrew

2008-01-01

The human visual system can notice differences between memories of previous visual inputs and perceptions of new visual inputs, but the comparison process that detects these differences has not been well characterized. This study tests the hypothesis that differences between the memory of a stimulus array and the perception of a new array are detected in a manner that is analogous to the detection of simple features in visual search tasks. That is, just as the presence of a task-relevant feature in visual search can be detected in parallel, triggering a rapid shift of attention to the object containing the feature, the presence of a memory-percept difference along a task-relevant dimension can be detected in parallel, triggering a rapid shift of attention to the changed object. Supporting evidence was obtained in a series of experiments that examined manual reaction times, saccadic reaction times, and event-related potential latencies. However, these experiments also demonstrated that a slow, limited-capacity process must occur before the observer can make a manual change-detection response. PMID:19653755

Altered brain serotonergic neurotransmission following caffeine withdrawal produces behavioral deficits in rats.

PubMed

Khaliq, Saima; Haider, Saida; Naqvi, Faizan; Perveen, Tahira; Saleem, Sadia; Haleem, Darakhshan Jabeen

2012-01-01

Caffeine administration has been shown to enhance performance and memory in rodents and humans while its withdrawal on the other hand produces neurobehavioral deficits which are thought to be mediated by alterations in monoamines neurotransmission. A role of decreased brain 5-HT (5-hydroxytryptamine, serotonin) levels has been implicated in impaired cognitive performance and depression. Memory functions of rats were assessed by Water Maze (WM) and immobility time by Forced Swim Test (FST). The results of this study showed that repeated caffeine administration for 6 days at 30 mg/kg dose significantly increases brain 5-HT (p<0.05) and 5-HIAA (p<0.05) levels and its withdrawal significantly (p<0.05) decreased brain 5-HT levels. A significant decrease in latency time was exhibited by rats in the WM repeatedly injected with caffeine. Withdrawal of caffeine however produced memory deficits and significantly increases the immobility time of rats in FST. The results of this study are linked with caffeine induced alterations in serotonergic neurotransmission and its role in memory and depression.

Low latency counter event indication

DOEpatents

Gara, Alan G [Mount Kisco, NY; Salapura, Valentina [Chappaqua, NY

2008-09-16

A hybrid counter array device for counting events with interrupt indication includes a first counter portion comprising N counter devices, each for counting signals representing event occurrences and providing a first count value representing lower order bits. An overflow bit device associated with each respective counter device is additionally set in response to an overflow condition. The hybrid counter array includes a second counter portion comprising a memory array device having N addressable memory locations in correspondence with the N counter devices, each addressable memory location for storing a second count value representing higher order bits. An operatively coupled control device monitors each associated overflow bit device and initiates incrementing a second count value stored at a corresponding memory location in response to a respective overflow bit being set. The incremented second count value is compared to an interrupt threshold value stored in a threshold register, and, when the second counter value is equal to the interrupt threshold value, a corresponding "interrupt arm" bit is set to enable a fast interrupt indication. On a subsequent roll-over of the lower bits of that counter, the interrupt will be fired.

Low latency counter event indication

DOEpatents

Gara, Alan G.; Salapura, Valentina

2010-08-24

A hybrid counter array device for counting events with interrupt indication includes a first counter portion comprising N counter devices, each for counting signals representing event occurrences and providing a first count value representing lower order bits. An overflow bit device associated with each respective counter device is additionally set in response to an overflow condition. The hybrid counter array includes a second counter portion comprising a memory array device having N addressable memory locations in correspondence with the N counter devices, each addressable memory location for storing a second count value representing higher order bits. An operatively coupled control device monitors each associated overflow bit device and initiates incrementing a second count value stored at a corresponding memory location in response to a respective overflow bit being set. The incremented second count value is compared to an interrupt threshold value stored in a threshold register, and, when the second counter value is equal to the interrupt threshold value, a corresponding "interrupt arm" bit is set to enable a fast interrupt indication. On a subsequent roll-over of the lower bits of that counter, the interrupt will be fired.

The effect of Vitamin E on learning and memory deficits in intrahippocampal kainate-induced temporal lobe epilepsy in rats.

PubMed

Kiasalari, Zahra; Khalili, Mohsen; Shafiee, Samaneh; Roghani, Mehrdad

2016-01-01

Since temporal lobe epilepsy (TLE) is associated with learning and memory impairment, we investigated the beneficial effect of Vitamin E on the impaired learning and memory in the intrahippocampal kainate model of TLE in rats. Rats were divided into sham, Vitamin E-treated sham, kainate, and Vitamin E-treated kainate. Intrahippocampal kainate was used for induction of epilepsy. Vitamin E was injected intraperitoneal (i.p.) at a dose of 200 mg/kg/day started 1 week before surgery until 1 h presurgery. Initial and step-through latencies in the passive avoidance test and alternation behavior percentage in Y-maze were finally determined in addition to measurement of some oxidative stress markers. Kainate injection caused a higher severity and rate of seizures and deteriorated learning and memory performance in passive avoidance paradigm and spontaneous alternation as an index of spatial recognition memory in Y-maze task. Intrahippocampal kainate also led to the elevation of malondialdehyde (MDA) and nitrite and reduced activity of superoxide dismutase (SOD). Vitamin E pretreatment significantly attenuated severity and incidence rate of seizures, significantly improved retrieval and recall in passive avoidance, did not ameliorate spatial memory deficit in Y-maze, and lowered MDA and enhanced SOD activity. Vitamin E improves passive avoidance learning and memory and part of its beneficial effect is due to its potential to mitigate hippocampal oxidative stress.

Study on fault-tolerant processors for advanced launch system

NASA Technical Reports Server (NTRS)

Shin, Kang G.; Liu, Jyh-Charn

1990-01-01

Issues related to the reliability of a redundant system with large main memory are addressed. The Fault-Tolerant Processor (FTP) for the Advanced Launch System (ALS) is used as a basis for the presentation. When the system is free of latent faults, the probability of system crash due to multiple channel faults is shown to be insignificant even when voting on the outputs of computing channels is infrequent. Using channel error maskers (CEMs) is shown to improve reliability more effectively than increasing redundancy or the number of channels for applications with long mission times. Even without using a voter, most memory errors can be immediately corrected by those CEMs implemented with conventional coding techniques. In addition to their ability to enhance system reliability, CEMs (with a very low hardware overhead) can be used to dramatically reduce not only the need of memory realignment, but also the time required to realign channel memories in case, albeit rare, such a need arises. Using CEMs, two different schemes were developed to solve the memory realignment problem. In both schemes, most errors are corrected by CEMs, and the remaining errors are masked by a voter.

Modeling criterion shifts and target checking in prospective memory monitoring.

PubMed

Horn, Sebastian S; Bayen, Ute J

2015-01-01

Event-based prospective memory (PM) involves remembering to perform intended actions after a delay. An important theoretical issue is whether and how people monitor the environment to execute an intended action when a target event occurs. Performing a PM task often increases the latencies in ongoing tasks. However, little is known about the reasons for this cost effect. This study uses diffusion model analysis to decompose monitoring processes in the PM paradigm. Across 4 experiments, performing a PM task increased latencies in an ongoing lexical decision task. A large portion of this effect was explained by consistent increases in boundary separation; additional increases in nondecision time emerged in a nonfocal PM task and explained variance in PM performance (Experiment 1), likely reflecting a target-checking strategy before and after the ongoing decision (Experiment 2). However, we found that possible target-checking strategies may depend on task characteristics. That is, instructional emphasis on the importance of ongoing decisions (Experiment 3) or the use of focal targets (Experiment 4) eliminated the contribution of nondecision time to the cost of PM, but left participants in a mode of increased cautiousness. The modeling thus sheds new light on the cost effect seen in many PM studies and suggests that people approach ongoing activities more cautiously when they need to remember an intended action. PsycINFO Database Record (c) 2015 APA, all rights reserved.

Neurotoxicity of neem commercial formulation (Azadirachta indica A. Juss) in adult zebrafish (Danio rerio).

PubMed

Bernardi, M M; Dias, S G; Barbosa, V E

2013-11-01

The neurotoxic effects of a commercial formulation of Azadirachta indica A. Juss, also called neem or nim, in adult zebrafish were determined using behavioral models. General activity, anxiety-like effects, and learning and memory in a passive avoidance task were assessed after exposure to 20 or 40 μl/L neem. The results showed that 20 μl/L neem reduced the number of runs. Both neem concentrations increased the number of climbs to the water surface, and 40 μl/L increased the number of tremors. In the anxiety test, the 20 μl/L dose increased the number of entries in the light side compared with controls, but the latency to enter the dark side and the freezing behavior in this side did not changed. In relation to controls, the 40 μl/L neem reduced the latency to enter in the light side, did not change the number of entries in this side and increased freezing behavior in the light side. In the passive avoidance test, pre-training and pre-test neem exposure to 40 μl/L decreased the response to the learning task. Thus, no impairment was observed in this behavioral test. We conclude that neem reduced general activity and increased anxiety-like behavior but did not affect learning and memory. Copyright © 2013 Elsevier B.V. All rights reserved.

Combined oral supplementation of chromium picolinate, docosahexaenoic acid, and boron enhances neuroprotection in rats fed a high-fat diet

PubMed

Orhan, Cemal; Şahin, Nurhan; Tuzcu, Zeynep; Komorowski, James R.; Şahin, Kazım

2017-11-13

Background/aim: A novel complex of a nutritional supplement (CDB) contains chromium picolinate (CrPic), phosphatidylserine (PS), docosahexaenoic acid (DHA), and boron (B). The present study aimed to investigate the effects of CDB on the metabolic profile and memory acquisition in rats fed a high-fat diet (HFD). Materials and methods: Male Wistar rats were divided into six groups and received either a regular diet or HFD supplemented with or without different levels of CDB (0, 11, or 22 mg/kg BW). Results: Rats fed the HFD had greater glucose, insulin, lipid profile, and serum malondialdehyde concentrations, but lower serotonin and tryptophan in the serum and brain and lower Cr concentrations in serum, kidney, brain, and liver (P < 0.0001). CDB complex supplementation reversed all the effects, and the reversal effect was more pronounced with HFD for some parameters. Latency was less (P < 0.05) but probe was greater (P < 0.0001) for rats fed a regular diet. Increasing CDB complex levels in the diets resulted in a linear decrease in latency (P < 0.0002) but a linear increase in probe (P < 0.0002). Conclusion: Findings of the present work indicate that the CDB complex could be considered as an alternative treatment for preventing certain metabolic diseases and improving neurological functions, such as learning and memory.

Estradiol treatment in preadolescent females enhances adolescent spatial memory and differentially modulates hippocampal region-specific phosphorylated ERK labeling.

PubMed

Wartman, Brianne C; Keeley, Robin J; Holahan, Matthew R

2012-10-24

Estrogen levels in rats are positively correlated with enhanced memory function and hippocampal dendritic spine density. There is much less work on the long-term effects of estradiol manipulation in preadolescent rats. The present work examined how injections of estradiol during postnatal days 19-22 (p19-22; preadolescence) affected water maze performance and hippocampal phosphorylated ERK labeling. To investigate this, half of the estradiol- and vehicle-treated female rats were trained on a water maze task 24h after the end of estradiol treatment (p23-27) while the other half was not trained. All female rats were tested on the water maze from p40 to p44 (adolescence) and hippocampal pERK1/2 labeling was assessed as a putative marker of neuronal plasticity. During adolescence, preadolescent-trained groups showed lower latencies than groups without preadolescent training. Retention data revealed lower latencies in both estradiol groups, whether preadolescent trained or not. Immunohistochemical detection of hippocampal pERK1/2 revealed elevations in granule cell labeling associated with the preadolescent trained groups and reductions in CA1 labeling associated with estradiol treatment. These results show a latent beneficial effect of preadolescent estradiol treatment on adolescent spatial performance and suggest an organizational effect of prepubescent exogenously applied estradiol. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

The spatial learning and memory performance in methamphetamine–sensitized and withdrawn rats

PubMed Central

Bigdeli, Imanollah; Asia, Masomeh Nikfarjam- Haft; Miladi-Gorji, Hossein; Fadaei, Atefeh

2015-01-01

Objective(s): There is controversial evidence about the effect of methamphetamine (METH) on spatial memory. We tested the time- dependent effects of METH on spatial short-term (working) and long-term (reference) memory in METH –sensitized and withdrawn rats in the Morris water maze. Materials and Methods: Rats were sensitized to METH (2 mg/kg, daily/5 days, SC). Rats were trained in water maze (4 trials/day/for 5 days). Probe test was performed 24 hr after training. Two days after probe test, working memory training (2 trials/day/for 5 days) was conducted. Acquisition–retention interval was 75 min. The treatment was continued per day 30 and 120 min before the test. Two groups of METH –sensitized rats were trained in reference memory after a longer period of withdrawal (30 days). Results: Sensitized rats exhibited significantly longer escape latencies on the training, spent significantly less time in the target zone (all, P<0.05), and their working memory impaired 30 min after injection. While, METH has no effect on the spatial learning process 120 min after injection, and rats spent significantly less time in the target zone (P<0.05), as well it has no effect on working memory. Also, impairment of reference memory persisted after prolonged abstinence. Conclusion: Our findings indicated that METH impaired spatial learning and memory 30 min after injection, but spared spatial learning, either acquisition or retention of spatial working, but partially impaired retention of spatial reference memory following 120 min after injection in sensitized rats, which persisted even after prolonged abstinence. PMID:25945235

The impact of micronutrient supplementation in alcohol-exposed pregnancies on information processing skills in Ukrainian infants.

PubMed

Kable, J A; Coles, C D; Keen, C L; Uriu-Adams, J Y; Jones, K L; Yevtushok, L; Kulikovsky, Y; Wertelecki, W; Pedersen, T L; Chambers, C D

2015-11-01

The potential of micronutrients to ameliorate the impact of prenatal alcohol exposure (PAE) was explored in a clinical trial conducted in Ukraine. Cardiac orienting responses (ORs) during a habituation/dishabituation learning paradigm were obtained from 6 to 12 month-olds to assess neurophysiological encoding and memory. Women who differed in prenatal alcohol use were recruited during pregnancy and assigned to a group (No study-provided supplements, multivitamin/mineral supplement, or multivitamin/mineral supplement plus choline supplement). Heart rate was collected for 30 s prior to stimulus onset and 12 s post-stimulus onset. Difference values (∆HR) for the first 3 trials of each condition were aggregated for analysis. Gestational blood samples were collected to assess maternal nutritional status and changes as a function of the intervention. Choline supplementation resulted in a greater ∆HR on the visual habituation trials for all infants and for the infants with no PAE on the dishabituation trials. The latency of the response was reduced in both conditions for all infants whose mothers received choline supplementation. Change in gestational choline level was positively related to ∆HR during habituation trials and levels of one choline metabolite, dimethylglycine (DMG), predicted ∆HR during habituation trials and latency of responses. A trend was found between DMG and ∆HR on the dishabituation trials and latency of the response. Supplementation did not affect ORs to auditory stimuli. Choline supplementation when administered together with routinely recommended multivitamin/mineral prenatal supplements during pregnancy may provide a beneficial impact to basic learning mechanisms involved in encoding and memory of environmental events in alcohol-exposed pregnancies as well as non- or low alcohol-exposed pregnancies. Changes in maternal nutrient status suggested that one mechanism by which choline supplementation may positively impact brain development is through prevention of fetal alcohol-related depletion of DMG, a metabolic nutrient that can protect against overproduction of glycine, during critical periods of neurogenesis. Copyright © 2015 Elsevier Inc. All rights reserved.

Protein kinase G confers survival advantage to Mycobacterium tuberculosis during latency-like conditions.

PubMed

Khan, Mehak Zahoor; Bhaskar, Ashima; Upadhyay, Sandeep; Kumari, Pooja; Rajmani, Raju S; Jain, Preeti; Singh, Amit; Kumar, Dhiraj; Bhavesh, Neel Sarovar; Nandicoori, Vinay Kumar

2017-09-29

Protein kinase G (PknG), a thioredoxin-fold-containing eukaryotic-like serine/threonine protein kinase, is a virulence factor in Mycobacterium tuberculosis , required for inhibition of phagolysosomal fusion. Here, we unraveled novel functional facets of PknG during latency-like conditions. We found that PknG mediates persistence under stressful conditions like hypoxia and abets drug tolerance. PknG mutant displayed minimal growth in nutrient-limited conditions, suggesting its role in modulating cellular metabolism. Intracellular metabolic profiling revealed that PknG is necessary for efficient metabolic adaptation during hypoxia. Notably, the PknG mutant exhibited a reductive shift in mycothiol redox potential and compromised stress response. Exposure to antibiotics and hypoxic environment resulted in higher oxidative shift in mycothiol redox potential of PknG mutant compared with the wild type. Persistence during latency-like conditions required kinase activity and thioredoxin motifs of PknG and is mediated through phosphorylation of a central metabolic regulator GarA. Finally, using a guinea pig model of infection, we assessed the in vivo role of PknG in manifestation of disease pathology and established a role for PknG in the formation of stable granuloma, hallmark structures of latent tuberculosis. Taken together, PknG-mediated GarA phosphorylation is important for maintenance of both mycobacterial physiology and redox poise, an axis that is dispensable for survival under normoxic conditions but is critical for non-replicating persistence of mycobacteria. In conclusion, we propose that PknG probably acts as a modulator of latency-associated signals. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

Transcranial magnetic stimulation in the semi-quantitative, pre-operative assessment of patients undergoing spinal deformity surgery.

PubMed

Glasby, Michael A; Tsirikos, Athanasios I; Henderson, Lindsay; Horsburgh, Gillian; Jordan, Brian; Michaelson, Ciara; Adams, Christopher I; Garrido, Enrique

2017-08-01

To compare measurements of motor evoked potential latency stimulated either magnetically (mMEP) or electrically (eMEP) and central motor conduction time (CMCT) made pre-operatively in conscious patients using transcranial and intra-operatively using electrical cortical stimulation before and after successful instrumentation for the treatment of adolescent idiopathic scoliosis. A group initially of 51 patients with adolescent idiopathic scoliosis aged 12-19 years was evaluated pre-operatively in the outpatients' department with transcranial magnetic stimulation. The neurophysiological data were then compared statistically with intra-operative responses elicited by transcranial electrical stimulation both before and after successful surgical intervention. MEPs were measured as the cortically evoked compound action potentials of Abductor hallucis. Minimum F-waves were measured using conventional nerve conduction methods and the lower motor neuron conduction time was calculated and this was subtracted from MEP latency to give CMCT. Pre-operative testing was well tolerated in our paediatric/adolescent patients. No neurological injury occurred in any patient in this series. There was no significant difference in the values of mMEP and eMEP latencies seen pre-operatively in conscious patients and intra-operatively in patients under anaesthetic. The calculated quantities mCMCT and eCMCT showed the same statistical correlations as the quantities mMEP and eMEP latency. The congruency of mMEP and eMEP and of mCMCT and eCMCT suggests that these measurements may be used comparatively and semi-quantitatively for the comparison of pre-, intra-, and post-operative spinal cord function in spinal deformity surgery.

Physical principles and current status of emerging non-volatile solid state memories

NASA Astrophysics Data System (ADS)

Wang, L.; Yang, C.-H.; Wen, J.

2015-07-01

Today the influence of non-volatile solid-state memories on persons' lives has become more prominent because of their non-volatility, low data latency, and high robustness. As a pioneering technology that is representative of non-volatile solidstate memories, flash memory has recently seen widespread application in many areas ranging from electronic appliances, such as cell phones and digital cameras, to external storage devices such as universal serial bus (USB) memory. Moreover, owing to its large storage capacity, it is expected that in the near future, flash memory will replace hard-disk drives as a dominant technology in the mass storage market, especially because of recently emerging solid-state drives. However, the rapid growth of the global digital data has led to the need for flash memories to have larger storage capacity, thus requiring a further downscaling of the cell size. Such a miniaturization is expected to be extremely difficult because of the well-known scaling limit of flash memories. It is therefore necessary to either explore innovative technologies that can extend the areal density of flash memories beyond the scaling limits, or to vigorously develop alternative non-volatile solid-state memories including ferroelectric random-access memory, magnetoresistive random-access memory, phase-change random-access memory, and resistive random-access memory. In this paper, we review the physical principles of flash memories and their technical challenges that affect our ability to enhance the storage capacity. We then present a detailed discussion of novel technologies that can extend the storage density of flash memories beyond the commonly accepted limits. In each case, we subsequently discuss the physical principles of these new types of non-volatile solid-state memories as well as their respective merits and weakness when utilized for data storage applications. Finally, we predict the future prospects for the aforementioned solid-state memories for the next generation of data-storage devices based on a comparison of their performance. [Figure not available: see fulltext.

Unforgeable Noise-Tolerant Quantum Tokens

NASA Astrophysics Data System (ADS)

Yao, Norman; Pastawski, Fernando; Jiang, Liang; Lukin, Mikhail; Cirac, Ignacio

2012-06-01

The realization of devices which harness the laws of quantum mechanics represents an exciting challenge at the interface of modern technology and fundamental science. An exemplary paragon of the power of such quantum primitives is the concept of ``quantum money.'' A dishonest holder of a quantum bank-note will invariably fail in any forging attempts; indeed, under assumptions of ideal measurements and decoherence-free memories such security is guaranteed by the no-cloning theorem. In any practical situation, however, noise, decoherence and operational imperfections abound. Thus, the development of secure ``quantum money''-type primitives capable of tolerating realistic infidelities is of both practical and fundamental importance. Here, we propose a novel class of such protocols and demonstrate their tolerance to noise; moreover, we prove their rigorous security by determining tight fidelity thresholds. Our proposed protocols require only the ability to prepare, store and measure single qubit quantum memories, making their experimental realization accessible with current technologies.

Fault Tolerant Characteristics of Artificial Neural Network Electronic Hardware

NASA Technical Reports Server (NTRS)

Zee, Frank

1995-01-01

The fault tolerant characteristics of analog-VLSI artificial neural network (with 32 neurons and 532 synapses) chips are studied by exposing them to high energy electrons, high energy protons, and gamma ionizing radiations under biased and unbiased conditions. The biased chips became nonfunctional after receiving a cumulative dose of less than 20 krads, while the unbiased chips only started to show degradation with a cumulative dose of over 100 krads. As the total radiation dose increased, all the components demonstrated graceful degradation. The analog sigmoidal function of the neuron became steeper (increase in gain), current leakage from the synapses progressively shifted the sigmoidal curve, and the digital memory of the synapses and the memory addressing circuits began to gradually fail. From these radiation experiments, we can learn how to modify certain designs of the neural network electronic hardware without using radiation-hardening techniques to increase its reliability and fault tolerance.

Nonvolatile Memory Technology for Space Applications

NASA Technical Reports Server (NTRS)

Oldham, Timothy R.; Irom, Farokh; Friendlich, Mark; Nguyen, Duc; Kim, Hak; Berg, Melanie; LaBel, Kenneth A.

2010-01-01

This slide presentation reviews several forms of nonvolatile memory for use in space applications. The intent is to: (1) Determine inherent radiation tolerance and sensitivities, (2) Identify challenges for future radiation hardening efforts, (3) Investigate new failure modes and effects, and technology modeling programs. Testing includes total dose, single event (proton, laser, heavy ion), and proton damage (where appropriate). Test vehicles are expected to be a variety of non-volatile memory devices as available including Flash (NAND and NOR), Charge Trap, Nanocrystal Flash, Magnetic Memory (MRAM), Phase Change--Chalcogenide, (CRAM), Ferroelectric (FRAM), CNT, and Resistive RAM.

Scalable printed electronics: an organic decoder addressing ferroelectric non-volatile memory.

PubMed

Ng, Tse Nga; Schwartz, David E; Lavery, Leah L; Whiting, Gregory L; Russo, Beverly; Krusor, Brent; Veres, Janos; Bröms, Per; Herlogsson, Lars; Alam, Naveed; Hagel, Olle; Nilsson, Jakob; Karlsson, Christer

2012-01-01

Scalable circuits of organic logic and memory are realized using all-additive printing processes. A 3-bit organic complementary decoder is fabricated and used to read and write non-volatile, rewritable ferroelectric memory. The decoder-memory array is patterned by inkjet and gravure printing on flexible plastics. Simulation models for the organic transistors are developed, enabling circuit designs tolerant of the variations in printed devices. We explain the key design rules in fabrication of complex printed circuits and elucidate the performance requirements of materials and devices for reliable organic digital logic.

Memory, Cognition and the Endogenous Evoked Potentials of the Brain: the Estimation of the Disturbance of Cognitive Functions and Capacity of Working Memory Without the Psychological Testing.

PubMed

Gnezditskiy, V V; Korepina, O S; Chatskaya, A V; Klochkova, O I

2017-01-01

Cognition, cognitive and memory impairments is widely discussed in the literature, especially in the psycho physiological and the neurologic. In essence, this literature is dedicated to the psycho physiological tests, different scales. However, instrument neurophysiologic methods not so widely are used for these purposes. This review is dedicated to the instrument methods of neurophysiology, in particular to the endogenous evoked potentials method Р 300 (by characteristic latency 300 ms), in the estimation of cognitive functions and memory, to their special features dependent on age and to special features to their changes with the pathology. Method cognitive EP - Р 300 is the response of the brain, recorded under the conditions of the identification of the significant distinguishing stimulus, it facilitates the inspection of cognitive functions and memory in the healthy persons and patients with different manifestation of cognitive impairments. In the review it is shown on the basis of literature and our own data, that working (operative) memory and the capacity of the working memory it can be evaluated with the aid of the indices Р 300 within the normal subject and with the pathology. Testing with the estimation of working memory according to latent period of the peak Р 300 can be carried out and when conducting psychological testing is not possible for any reasons. Together with these cognitive EP are used for evidence pharmacotherapy of many neurotropic drugs.

Verapamil enhances acute stress or glucocorticoid-induced deficits in retrieval of long-term memory in rats.

PubMed

Rashidy-Pour, Ali; Vafaei, Abbas Ali; Taherian, Abbas Ali; Miladi-Gorji, Hossein; Sadeghi, Hassan; Fathollahi, Yaghoub; Bandegi, Ahmad Reza

2009-10-12

This study was designed to investigate an interaction between acute restraint stress and corticosterone with verapamil, a blocker of L-type voltage-dependent calcium (VDC) channels on retrieval of long-term memory. Young adult male rats were trained in one trial inhibitory avoidance task (0.5 mA, 3 s footshock). On retention test given 48 h after training, the latency to re-enter dark compartment of the apparatus was recorded. In Experiment 1, verapamil pretreatment (5, 10, or 20 mg/kg) enhanced the impairing effects of acute stress (which was applied for 10 min in a Plexiglass tube 30 min before the retention test) on memory retrieval. The applied stress increased circulating corticosterone levels as assessed immediately after the retention test, indicating that stress-induced impairment of memory retrieval is mediated, in part, by increased plasma levels of glucocorticoids. Verapamil did not change this response. In Experiment 2, pretreatment of an intermediate dose of verapamil also enhanced corticosterone-induced impairment of memory retrieval. In Experiments 3 and 4, acute stress or corticosterone did not change motor activity with or without prior treatment of verapamil, suggesting that stress or glucocorticoid-induced impairment of memory retrieval is not due to any gross disturbances in motor performance of animals. These findings indicate that blockade of L-type VDC channels enhances stress or glucocorticoid-induced impairment of memory retrieval, and provide evidence for the existence of an interaction between glucocorticoids and L-type VDC channels on memory retrieval.

Skin conductance and memory fragmentation after exposure to an emotional film clip in depersonalization disorder.

PubMed

Giesbrecht, Timo; Merckelbach, Harald; van Oorsouw, Kim; Simeon, Daphne

2010-05-30

It is often assumed that when confronted with an emotional event, patients with DPD inhibit information processing. It is also thought that this fosters memory fragmentation. This hypothesis has not been tested in chronic depersonalization. The aim of this study was to investigate the temporal pattern of autonomic responding to emotional material in depersonalization disorder, along with concomitant deficits in subjective and objective memory formation (i.e., difficulties to form a coherent narrative consisting of an ordered sequence of events). Participants with depersonalization disorder (n=14) and healthy control participants (n=14) viewed an emotional video clip while their skin conductance (SC) levels were measured. Peritraumatic dissociation was measured before and after the clip, and memory performance was measured 35 min after viewing. Compared to controls, depersonalized participants exhibited a distinctly different temporal pattern of autonomic responding, characterized by an earlier peak and subsequent flattening of SCLs. Maximum SCLs did not differ between the two groups. Moreover, unlike the control group, depersonalized participants showed no SC recovery after clip offset. In terms of memory performance, patients exhibited objective memory fragmentation, which they also reported subjectively. However, they did not differ from controls in free recall performance. Apparently, emotional responding in DPD is characterized by a shortened latency to peak with subsequent flattening and is accompanied by memory fragmentation in the light of otherwise unremarkable memory functioning. Copyright 2010 Elsevier Ireland Ltd. All rights reserved.

Design and testing of the first 2D Prototype Vertically Integrated Pattern Recognition Associative Memory

NASA Astrophysics Data System (ADS)

Liu, T.; Deptuch, G.; Hoff, J.; Jindariani, S.; Joshi, S.; Olsen, J.; Tran, N.; Trimpl, M.

2015-02-01

An associative memory-based track finding approach has been proposed for a Level 1 tracking trigger to cope with increasing luminosities at the LHC. The associative memory uses a massively parallel architecture to tackle the intrinsically complex combinatorics of track finding algorithms, thus avoiding the typical power law dependence of execution time on occupancy and solving the pattern recognition in times roughly proportional to the number of hits. This is of crucial importance given the large occupancies typical of hadronic collisions. The design of an associative memory system capable of dealing with the complexity of HL-LHC collisions and with the short latency required by Level 1 triggering poses significant, as yet unsolved, technical challenges. For this reason, an aggressive R&D program has been launched at Fermilab to advance state of-the-art associative memory technology, the so called VIPRAM (Vertically Integrated Pattern Recognition Associative Memory) project. The VIPRAM leverages emerging 3D vertical integration technology to build faster and denser Associative Memory devices. The first step is to implement in conventional VLSI the associative memory building blocks that can be used in 3D stacking; in other words, the building blocks are laid out as if it is a 3D design. In this paper, we report on the first successful implementation of a 2D VIPRAM demonstrator chip (protoVIPRAM00). The results show that these building blocks are ready for 3D stacking.

Design and testing of the first 2D Prototype Vertically Integrated Pattern Recognition Associative Memory

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

Liu, T.; Deptuch, G.; Hoff, J.

An associative memory-based track finding approach has been proposed for a Level 1 tracking trigger to cope with increasing luminosities at the LHC. The associative memory uses a massively parallel architecture to tackle the intrinsically complex combinatorics of track finding algorithms, thus avoiding the typical power law dependence of execution time on occupancy and solving the pattern recognition in times roughly proportional to the number of hits. This is of crucial importance given the large occupancies typical of hadronic collisions. The design of an associative memory system capable of dealing with the complexity of HL-LHC collisions and with the shortmore » latency required by Level 1 triggering poses significant, as yet unsolved, technical challenges. For this reason, an aggressive R&D program has been launched at Fermilab to advance state of-the-art associative memory technology, the so called VIPRAM (Vertically Integrated Pattern Recognition Associative Memory) project. The VIPRAM leverages emerging 3D vertical integration technology to build faster and denser Associative Memory devices. The first step is to implement in conventional VLSI the associative memory building blocks that can be used in 3D stacking, in other words, the building blocks are laid out as if it is a 3D design. In this paper, we report on the first successful implementation of a 2D VIPRAM demonstrator chip (protoVIPRAM00). The results show that these building blocks are ready for 3D stacking.« less

Auditory evoked potentials in children and adolescents with Down syndrome.

PubMed

Gregory, Letícia; Rosa, Rafael F M; Zen, Paulo R G; Sleifer, Pricila

2018-01-01

Down syndrome, or trisomy 21, is the most common genetic alteration in humans. The syndrome presents with several features, including hearing loss and changes in the central nervous system, which may affect language development in children and lead to school difficulties. The present study aimed to investigate group differences in the central auditory system by long-latency auditory evoked potentials and cognitive potential. An assessment of 23 children and adolescents with Down syndrome was performed, and a control group composed of 43 children and adolescents without genetic and/or neurological changes was used for comparison. All children underwent evaluation with pure tone and vocal audiometry, acoustic immitance measures, long-latency auditory evoked potentials, and cognitive potential. Longer latencies of the waves were found in the Down syndrome group than the control group, without significant differences in amplitude, suggesting that individuals with Down syndrome have difficulty in discrimination and auditory memory. It is, therefore, important to stimulate and monitor these children in order to enable adequate development and improve their life quality. We also emphasize the importance of the application of auditory evoked potentials in clinical practice, in order to contribute to the early diagnosis of hearing alterations and the development of more research in this area. © 2017 Wiley Periodicals, Inc.

Attention in essential tremor: evidence from event-related potentials.

PubMed

Pauletti, C; Mannarelli, D; Locuratolo, N; Vanacore, N; De Lucia, M C; Mina, C; Fattapposta, F

2013-07-01

Clinically subtle executive dysfunctions have recently been described in essential tremor (ET), though the presence of attentional deficits is still unclear. We investigated the psychophysiological aspects of attention in ET, using event-related potentials (ERPs). Twenty-one non-demented patients with ET and 21 age- and sex-matched healthy controls underwent a psychophysiological evaluation. P300 components and the Contingent Negative Variation (CNV) were recorded. The latencies and amplitudes of the P3a and P3b subcomponents and CNV areas were evaluated. Possible correlations between clinical parameters and ERP data were investigated. P3a latency was significantly longer in the ET group (p < 0.05), while no differences emerged between patients and controls in P3b latency. No differences were observed between the two groups in the CNV parameters. ET patients display a difficulty in the response to novelty and in the recruitment of prefrontal attentive circuits, while the memory context-updating process appears to be spared. This selective cognitive dysfunction does not appear to interfere with the attentional set linked to the expectancy evaluated during a complex choice-reaction time task, which is preserved in ET. This multitask psychophysiological approach reveals the presence of a peculiar attentional deficit in patients with ET, thus expanding the clinical features of this disease.

Reconfigurable PCI Express cards for low-latency data transport in HEP experiments

NASA Astrophysics Data System (ADS)

Ammendola, R.; Biagioni, A.; Cretaro, P.; Frezza, O.; Lamanna, G.; Lo Cicero, F.; Lonardo, A.; Martinelli, M.; Paolucci, P. S.; Pastorelli, E.; Pontisso, L.; Simula, F.; Vicini, P.

2017-01-01

State-of-the-art technology supports the High Energy Physics community in addressing the problem of managing an overwhelming amount of experimental data. From the point of view of communication between the detectors' readout system and computing nodes, the critical issues are the following: latency, moving data in a deterministic and low amount of time; bandwidth, guaranteeing the maximum capability of the link and communication protocol adopted; endpoint consolidation, tight aggregation of channels on a single board. This contribution describes the status and performances of the NaNet project, whose goal is the design of a family of FPGA-based PCIe network interface cards. The efforts of the team are focused on implementing a low-latency, real-time data transport mechanism between the board network multi-channel system and CPU and GPU accelerators memories on the host. Several opportunities concerning technical solutions and scientific applications have been explored: NaNet-1 with a single GbE I/O interface, and NaNet-10, offering four 10GbE ports, for activities related to the GPU-based real-time trigger of NA62 experiment at CERN; NaNet ^3 , with four 2.5Gbit optical channels, developed for the KM3NeT-ITALIA underwater neutrino telescope.

Virtual Morris task responses in individuals in an abstinence phase from alcohol.

PubMed

Ceccanti, Mauro; Coriale, Giovanna; Hamilton, Derek A; Carito, Valentina; Coccurello, Roberto; Scalese, Bruna; Ciafrè, Stefania; Codazzo, Claudia; Messina, Marisa Patrizia; Chaldakov, George N; Fiore, Marco

2018-02-01

The present study was aimed at examining spatial learning and memory, in 33 men and 12 women with alcohol use disorder (AUD) undergoing ethanol detoxification, by using a virtual Morris task. As controls, we recruited 29 men and 10 women among episodic drinkers without a history of alcohol addiction or alcohol-related diseases. Elevated latency to the first movement in all trials was observed only in AUD persons; furthermore, control women had longer latencies compared with control men. Increased time spent to reach the hidden platform in the learning phase was found for women of both groups compared with men, in particular during trial 3. As predicted, AUD persons (more evident in men) spent less time in the target quadrant during the probe trial; however, AUD women had longer latencies to reach the platform in the visible condition during trials 6 and 7 that resulted in a greater distance moved. As for the probe trial, men of both groups showed increased virtual locomotion compared with the women of both groups. The present investigation confirms and extends previous studies showing (i) different gender responses in spatial learning tasks, (ii) some alterations due to alcohol addiction in virtual spatial learning, and (iii) differences between AUD men and AUD women in spatial-behaviour-related paradigms.

Influence of an immunodominant herpes simplex virus type 1 CD8+ T cell epitope on the target hierarchy and function of subdominant CD8+ T cells

PubMed Central

2017-01-01

Herpes simplex virus type 1 (HSV-1) latency in sensory ganglia such as trigeminal ganglia (TG) is associated with a persistent immune infiltrate that includes effector memory CD8+ T cells that can influence HSV-1 reactivation. In C57BL/6 mice, HSV-1 induces a highly skewed CD8+ T cell repertoire, in which half of CD8+ T cells (gB-CD8s) recognize a single epitope on glycoprotein B (gB498-505), while the remainder (non-gB-CD8s) recognize, in varying proportions, 19 subdominant epitopes on 12 viral proteins. The gB-CD8s remain functional in TG throughout latency, while non-gB-CD8s exhibit varying degrees of functional compromise. To understand how dominance hierarchies relate to CD8+ T cell function during latency, we characterized the TG-associated CD8+ T cells following corneal infection with a recombinant HSV-1 lacking the immunodominant gB498-505 epitope (S1L). S1L induced a numerically equivalent CD8+ T cell infiltrate in the TG that was HSV-specific, but lacked specificity for gB498-505. Instead, there was a general increase of non-gB-CD8s with specific subdominant epitopes arising to codominance. In a latent S1L infection, non-gB-CD8s in the TG showed a hierarchy targeting different epitopes at latency compared to at acute times, and these cells retained an increased functionality at latency. In a latent S1L infection, these non-gB-CD8s also display an equivalent ability to block HSV reactivation in ex vivo ganglionic cultures compared to TG infected with wild type HSV-1. These data indicate that loss of the immunodominant gB498-505 epitope alters the dominance hierarchy and reduces functional compromise of CD8+ T cells specific for subdominant HSV-1 epitopes during viral latency. PMID:29206240

Introducing the Event Related Fixed Interval Area (ERFIA) Multilevel Technique: a Method to Analyze the Complete Epoch of Event-Related Potentials at Single Trial Level

PubMed Central

Vossen, Catherine J.; Vossen, Helen G. M.; Marcus, Marco A. E.; van Os, Jim; Lousberg, Richel

2013-01-01

In analyzing time-locked event-related potentials (ERPs), many studies have focused on specific peaks and their differences between experimental conditions. In theory, each latency point after a stimulus contains potentially meaningful information, regardless of whether it is peak-related. Based on this assumption, we introduce a new concept which allows for flexible investigation of the whole epoch and does not primarily focus on peaks and their corresponding latencies. For each trial, the entire epoch is partitioned into event-related fixed-interval areas under the curve (ERFIAs). These ERFIAs, obtained at single trial level, act as dependent variables in a multilevel random regression analysis. The ERFIA multilevel method was tested in an existing ERP dataset of 85 healthy subjects, who underwent a rating paradigm of 150 painful and non-painful somatosensory electrical stimuli. We modeled the variability of each consecutive ERFIA with a set of predictor variables among which were stimulus intensity and stimulus number. Furthermore, we corrected for latency variations of the P2 (260 ms). With respect to known relationships between stimulus intensity, habituation, and pain-related somatosensory ERP, the ERFIA method generated highly comparable results to those of commonly used methods. Notably, effects on stimulus intensity and habituation were also observed in non-peak-related latency ranges. Further, cortical processing of actual stimulus intensity depended on the intensity of the previous stimulus, which may reflect pain-memory processing. In conclusion, the ERFIA multilevel method is a promising tool that can be used to study event-related cortical processing. PMID:24224018

A double-blind, placebo-controlled, ascending-dose, randomized study to evaluate the safety, tolerability and effects on cognition of AL-108 after 12 weeks of intranasal administration in subjects with mild cognitive impairment.

PubMed

Morimoto, Bruce H; Schmechel, Don; Hirman, Joe; Blackwell, Andrew; Keith, Julian; Gold, Michael

2013-01-01

AL-108-211 was a placebo-controlled, ascending-dose study that explored the safety, tolerability and efficacy of 12 weeks of treatment with AL-108 in subjects with amnestic mild cognitive impairment. A total of 144 subjects were randomized in a 2:1 drug:placebo ratio. Subjects were enrolled into the low-dose group or placebo and then to the high-dose group or placebo. Pooling of the placebo groups yielded 3 groups (approx. 48/group) whose baseline demographics and disease characteristics were well matched. AL-108 was generally safe and well tolerated. Analyses of efficacy data failed to detect a statistically significant difference between the treatment groups on the composite cognitive memory score. Analyses of the individual cognitive tasks identified signals of potential efficacy in 2 tests of memory and attention. These data suggest that AL-108 was generally safe, well tolerated and merits additional investigation as a treatment for Alzheimer's disease. Copyright © 2013 S. Karger AG, Basel.

Mini-Ckpts: Surviving OS Failures in Persistent Memory

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

Fiala, David; Mueller, Frank; Ferreira, Kurt Brian

Concern is growing in the high-performance computing (HPC) community on the reliability of future extreme-scale systems. Current efforts have focused on application fault-tolerance rather than the operating system (OS), despite the fact that recent studies have suggested that failures in OS memory are more likely. The OS is critical to a system's correct and efficient operation of the node and processes it governs -- and in HPC also for any other nodes a parallelized application runs on and communicates with: Any single node failure generally forces all processes of this application to terminate due to tight communication in HPC. Therefore,more » the OS itself must be capable of tolerating failures. In this work, we introduce mini-ckpts, a framework which enables application survival despite the occurrence of a fatal OS failure or crash. Mini-ckpts achieves this tolerance by ensuring that the critical data describing a process is preserved in persistent memory prior to the failure. Following the failure, the OS is rejuvenated via a warm reboot and the application continues execution effectively making the failure and restart transparent. The mini-ckpts rejuvenation and recovery process is measured to take between three to six seconds and has a failure-free overhead of between 3-5% for a number of key HPC workloads. In contrast to current fault-tolerance methods, this work ensures that the operating and runtime system can continue in the presence of faults. This is a much finer-grained and dynamic method of fault-tolerance than the current, coarse-grained, application-centric methods. Handling faults at this level has the potential to greatly reduce overheads and enables mitigation of additional fault scenarios.« less

High-throughput state-machine replication using software transactional memory.

PubMed

Zhao, Wenbing; Yang, William; Zhang, Honglei; Yang, Jack; Luo, Xiong; Zhu, Yueqin; Yang, Mary; Luo, Chaomin

2016-11-01

State-machine replication is a common way of constructing general purpose fault tolerance systems. To ensure replica consistency, requests must be executed sequentially according to some total order at all non-faulty replicas. Unfortunately, this could severely limit the system throughput. This issue has been partially addressed by identifying non-conflicting requests based on application semantics and executing these requests concurrently. However, identifying and tracking non-conflicting requests require intimate knowledge of application design and implementation, and a custom fault tolerance solution developed for one application cannot be easily adopted by other applications. Software transactional memory offers a new way of constructing concurrent programs. In this article, we present the mechanisms needed to retrofit existing concurrency control algorithms designed for software transactional memory for state-machine replication. The main benefit for using software transactional memory in state-machine replication is that general purpose concurrency control mechanisms can be designed without deep knowledge of application semantics. As such, new fault tolerance systems based on state-machine replications with excellent throughput can be easily designed and maintained. In this article, we introduce three different concurrency control mechanisms for state-machine replication using software transactional memory, namely, ordered strong strict two-phase locking, conventional timestamp-based multiversion concurrency control, and speculative timestamp-based multiversion concurrency control. Our experiments show that speculative timestamp-based multiversion concurrency control mechanism has the best performance in all types of workload, the conventional timestamp-based multiversion concurrency control offers the worst performance due to high abort rate in the presence of even moderate contention between transactions. The ordered strong strict two-phase locking mechanism offers the simplest solution with excellent performance in low contention workload, and fairly good performance in high contention workload.

Fasting glucose and glucose tolerance as potential predictors of neurocognitive function among nondiabetic older adults.

PubMed

Sims Wright, Regina; Levy, Shellie-Anne T; Katzel, Leslie I; Rosenberger, William F; Manukyan, Zorayr; Whitfield, Keith E; Waldstein, Shari R

2015-01-01

Significant evidence has demonstrated that Type 2 diabetes mellitus and related precursors are associated with diminished neurocognitive function and risk of dementia among older adults. However, very little research has examined relations of glucose regulation to neurocognitive function among older adults free of these conditions. The primary aim of this investigation was to examine associations among fasting glucose, glucose tolerance, and neurocognitive function among nondiabetic older adults. The secondary aim was to examine age, gender, and education as potential effect modifiers. The study employed a cross-sectional, correlational study design. Participants were 172 older adults with a mean age of 64.43 years (SD = 13.09). The sample was 58% male and 87% White. Participants completed an oral glucose tolerance test as part of a larger study. Trained psychometricians administered neuropsychological tests that assessed performance in the domains of response inhibition, nonverbal memory, verbal memory, attention and working memory, visuoconstructional abilities, visuospatial abilities, psychomotor speed and executive function, and motor speed and manual dexterity. Linear multiple regressions were run to test study aims. No significant main effects of fasting glucose and 2-hour glucose emerged for performance on any neurocognitive test; however, significant interactions were present. Higher fasting glucose was associated with poorer short-term verbal memory performance among men, but unexpectedly better response inhibition and long-term verbal memory performance for participants over age 70. Higher 2-hour glucose values were associated with reduced divided attention performance among participants with less than a high school education. Mixed findings suggest that glucose levels may be both beneficial and deleterious to neurocognition among nondiabetic older adults. Additional studies with healthy older adults are needed to confirm this unexpected pattern of associations; however, findings have implications for the importance of maintaining healthy glucose levels in older adulthood.

High-throughput state-machine replication using software transactional memory

PubMed Central

Yang, William; Zhang, Honglei; Yang, Jack; Luo, Xiong; Zhu, Yueqin; Yang, Mary; Luo, Chaomin

2017-01-01

State-machine replication is a common way of constructing general purpose fault tolerance systems. To ensure replica consistency, requests must be executed sequentially according to some total order at all non-faulty replicas. Unfortunately, this could severely limit the system throughput. This issue has been partially addressed by identifying non-conflicting requests based on application semantics and executing these requests concurrently. However, identifying and tracking non-conflicting requests require intimate knowledge of application design and implementation, and a custom fault tolerance solution developed for one application cannot be easily adopted by other applications. Software transactional memory offers a new way of constructing concurrent programs. In this article, we present the mechanisms needed to retrofit existing concurrency control algorithms designed for software transactional memory for state-machine replication. The main benefit for using software transactional memory in state-machine replication is that general purpose concurrency control mechanisms can be designed without deep knowledge of application semantics. As such, new fault tolerance systems based on state-machine replications with excellent throughput can be easily designed and maintained. In this article, we introduce three different concurrency control mechanisms for state-machine replication using software transactional memory, namely, ordered strong strict two-phase locking, conventional timestamp-based multiversion concurrency control, and speculative timestamp-based multiversion concurrency control. Our experiments show that speculative timestamp-based multiversion concurrency control mechanism has the best performance in all types of workload, the conventional timestamp-based multiversion concurrency control offers the worst performance due to high abort rate in the presence of even moderate contention between transactions. The ordered strong strict two-phase locking mechanism offers the simplest solution with excellent performance in low contention workload, and fairly good performance in high contention workload. PMID:29075049

Phosphoproteomics and Bioinformatics Analyses of Spinal Cord Proteins in Rats with Morphine Tolerance

PubMed Central

Liaw, Wen-Jinn; Tsao, Cheng-Ming; Huang, Go-Shine; Wu, Chin-Chen; Ho, Shung-Tai; Wang, Jhi-Joung; Tao, Yuan-Xiang; Shui, Hao-Ai

2014-01-01

Introduction Morphine is the most effective pain-relieving drug, but it can cause unwanted side effects. Direct neuraxial administration of morphine to spinal cord not only can provide effective, reliable pain relief but also can prevent the development of supraspinal side effects. However, repeated neuraxial administration of morphine may still lead to morphine tolerance. Methods To better understand the mechanism that causes morphine tolerance, we induced tolerance in rats at the spinal cord level by giving them twice-daily injections of morphine (20 µg/10 µL) for 4 days. We confirmed tolerance by measuring paw withdrawal latencies and maximal possible analgesic effect of morphine on day 5. We then carried out phosphoproteomic analysis to investigate the global phosphorylation of spinal proteins associated with morphine tolerance. Finally, pull-down assays were used to identify phosphorylated types and sites of 14-3-3 proteins, and bioinformatics was applied to predict biological networks impacted by the morphine-regulated proteins. Results Our proteomics data showed that repeated morphine treatment altered phosphorylation of 10 proteins in the spinal cord. Pull-down assays identified 2 serine/threonine phosphorylated sites in 14-3-3 proteins. Bioinformatics further revealed that morphine impacted on cytoskeletal reorganization, neuroplasticity, protein folding and modulation, signal transduction and biomolecular metabolism. Conclusions Repeated morphine administration may affect multiple biological networks by altering protein phosphorylation. These data may provide insight into the mechanism that underlies the development of morphine tolerance. PMID:24392096

Dynamic modulation of innate immunity programming and memory.

PubMed

Yuan, Ruoxi; Li, Liwu

2016-01-01

Recent progress harkens back to the old theme of immune memory, except this time in the area of innate immunity, to which traditional paradigm only prescribes a rudimentary first-line defense function with no memory. However, both in vitro and in vivo studies reveal that innate leukocytes may adopt distinct activation states such as priming, tolerance, and exhaustion, depending upon the history of prior challenges. The dynamic programming and potential memory of innate leukocytes may have far-reaching consequences in health and disease. This review aims to provide some salient features of innate programing and memory, patho-physiological consequences, underlying mechanisms, and current pressing issues.

FN400 potentials are functionally identical to N400 potentials and reflect semantic processing during recognition testing

PubMed Central

Voss, Joel L.; Federmeier, Kara D.

2010-01-01

The “F” in FN400 denotes a more frontal scalp distribution relative to the morphologically similar N400 component—a distinction consistent with the hypothesized distinct roles of FN400 in familiarity memory versus N400 in language. However, no direct comparisons have substantiated these assumed dissimilarities. To this end, we manipulated short-term semantic priming during a recognition test. Semantic priming effects on N400 were indistinguishable from memory effects at the same latency, and semantic priming strongly modulated the “FN400,” despite having no influence on familiarity memory. Thus, no evidence suggested either electrophysiological or functional differences between the N400 and FN400, and findings were contrary to the linking of the “FN400” to familiarity. Instead, it appears that semantic/conceptual priming (reflected in the N400) occurs during recognition tests, and is frequently (mis)labeled as FN400 and attributed to familiarity. PMID:20701709

Evidence for age-related changes to temporal attention and memory from the choice time production task

PubMed Central

Gooch, Cynthia M.; Stern, Yaakov; Rakitin, Brian C.

2009-01-01

The effect of aging on interval timing was examined using a choice time production task, which required participants to choose a key response based on the location of the stimulus, but to delay responding until after a learned time interval. Experiment 1 varied attentional demands of the response choice portion of the task by varying difficulty of stimulus-response mapping. Choice difficulty affected temporal accuracy equally in both age groups, but older participants’ response latencies were more variable under more difficult response choice conditions. Experiment 2 tested the contribution of long-term memory to differences in choice time production between age groups over 3 days of testing. Direction of errors in time production between the two age groups diverged over the 3 sessions, but variability did not differ. Results from each experiment separately show age-related changes to attention and memory in temporal processing using different measures and manipulations in the same task. PMID:19132578

A performance comparison of the IBM RS/6000 and the Astronautics ZS-1

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

Smith, W.M.; Abraham, S.G.; Davidson, E.S.

1991-01-01

Concurrent uniprocessor architectures, of which vector and superscalar are two examples, are designed to capitalize on fine-grain parallelism. The authors have developed a performance evaluation method for comparing and improving these architectures, and in this article they present the methodology and a detailed case study of two machines. The runtime of many programs is dominated by time spent in loop constructs - for example, Fortran Do-loops. Loops generally comprise two logical processes: The access process generates addresses for memory operations while the execute process operates on floating-point data. Memory access patterns typically can be generated independently of the data inmore » the execute process. This independence allows the access process to slip ahead, thereby hiding memory latency. The IBM 360/91 was designed in 1967 to achieve slip dynamically, at runtime. One CPU unit executes integer operations while another handles floating-point operations. Other machines, including the VAX 9000 and the IBM RS/6000, use a similar approach.« less

[Effects of chrysalis oil on learning, memory and oxidative stress in D-galactose-induced ageing model of mice].

PubMed

Chen, Weiping; Yang, Qiongjie; Wei, Xing

2013-11-01

To investigate the effects of chrysalis oil on learning, memory and oxidative stress in D-galactose-induced ageing model of mice. Mice were injected intraperitoneally with D-galactose daily and received chrysalis oil intragastrically simultaneously for 30 d. Then mice underwent space navigation test and spatial probe test, superoxide dismutase (SOD), glutathione peroxidase (GSH-PX) activity and malondialdehyde (MDA) contents in mouse brain were measured. Compared to model group, escape latency in mice treated with 6 ml/kg*d chrysalis oil was significantly shorter (P<0.05), crossing times in 12 ml/kg*d group and 6 ml/kg*d group treated with chrysalis oil were significantly increased (P<0.05). Chrysalis oil treatment (12ml/kg*d) significantly increased SOD and GSH-PX activity and reduced MDA contents in brain of D-galactose-induced aging mice. Chrysalis oil can improve the ability of learning and memory in D-galactose-induced aging mice, and inhibit peroxidation in brain tissue.

The N400 reveals how personal semantics is processed: Insights into the nature and organization of self-knowledge

PubMed Central

Federmeier, Kara D.

2017-01-01

There is growing recognition that some important forms of long-term memory are difficult to classify into one of the well-studied memory subtypes. One example is personal semantics. Like the episodes that are stored as part of one’s autobiography, personal semantics is linked to an individual, yet, like general semantic memory, it is detached from a specific encoding context. Access to general semantics elicits an electrophysiological response known as the N400, which has been characterized across three decades of research; surprisingly, this response has not been fully examined in the context of personal semantics. In this study, we assessed responses to congruent and incongruent statements about people’s own, personal preferences. We found that access to personal preferences elicited N400 responses, with congruency effects that were similar in latency and distribution to those for general semantic statements elicited from the same participants. These results suggest that the processing of personal and general semantics share important functional and neurobiological features. PMID:26825011

Non-binary LDPC-coded modulation for high-speed optical metro networks with backpropagation

NASA Astrophysics Data System (ADS)

Arabaci, Murat; Djordjevic, Ivan B.; Saunders, Ross; Marcoccia, Roberto M.

2010-01-01

To simultaneously mitigate the linear and nonlinear channel impairments in high-speed optical communications, we propose the use of non-binary low-density-parity-check-coded modulation in combination with a coarse backpropagation method. By employing backpropagation, we reduce the memory in the channel and in return obtain significant reductions in the complexity of the channel equalizer which is exponentially proportional to the channel memory. We then compensate for the remaining channel distortions using forward error correction based on non-binary LDPC codes. We propose non-binary-LDPC-coded modulation scheme because, compared to bit-interleaved binary-LDPC-coded modulation scheme employing turbo equalization, the proposed scheme lowers the computational complexity and latency of the overall system while providing impressively larger coding gains.

Merlin - Massively parallel heterogeneous computing

NASA Technical Reports Server (NTRS)

Wittie, Larry; Maples, Creve

1989-01-01

Hardware and software for Merlin, a new kind of massively parallel computing system, are described. Eight computers are linked as a 300-MIPS prototype to develop system software for a larger Merlin network with 16 to 64 nodes, totaling 600 to 3000 MIPS. These working prototypes help refine a mapped reflective memory technique that offers a new, very general way of linking many types of computer to form supercomputers. Processors share data selectively and rapidly on a word-by-word basis. Fast firmware virtual circuits are reconfigured to match topological needs of individual application programs. Merlin's low-latency memory-sharing interfaces solve many problems in the design of high-performance computing systems. The Merlin prototypes are intended to run parallel programs for scientific applications and to determine hardware and software needs for a future Teraflops Merlin network.

An electrophysiological investigation of memory encoding, depth of processing, and word frequency in humans.

PubMed

Guo, Chunyan; Zhu, Ying; Ding, Jinhong; Fan, Silu; Paller, Ken A

2004-02-12

Memory encoding can be studied by monitoring brain activity correlated with subsequent remembering. To understand brain potentials associated with encoding, we compared multiple factors known to affect encoding. Depth of processing was manipulated by requiring subjects to detect animal names (deep encoding) or boldface (shallow encoding) in a series of Chinese words. Recognition was more accurate with deep than shallow encoding, and for low- compared to high-frequency words. Potentials were generally more positive for subsequently recognized versus forgotten words; for deep compared to shallow processing; and, for remembered words only, for low- than for high-frequency words. Latency and topographic differences between these potentials suggested that several factors influence the effectiveness of encoding and can be distinguished using these methods, even with Chinese logographic symbols.

Dynamic interactions between visual working memory and saccade target selection

PubMed Central

Schneegans, Sebastian; Spencer, John P.; Schöner, Gregor; Hwang, Seongmin; Hollingworth, Andrew

2014-01-01

Recent psychophysical experiments have shown that working memory for visual surface features interacts with saccadic motor planning, even in tasks where the saccade target is unambiguously specified by spatial cues. Specifically, a match between a memorized color and the color of either the designated target or a distractor stimulus influences saccade target selection, saccade amplitudes, and latencies in a systematic fashion. To elucidate these effects, we present a dynamic neural field model in combination with new experimental data. The model captures the neural processes underlying visual perception, working memory, and saccade planning relevant to the psychophysical experiment. It consists of a low-level visual sensory representation that interacts with two separate pathways: a spatial pathway implementing spatial attention and saccade generation, and a surface feature pathway implementing color working memory and feature attention. Due to bidirectional coupling between visual working memory and feature attention in the model, the working memory content can indirectly exert an effect on perceptual processing in the low-level sensory representation. This in turn biases saccadic movement planning in the spatial pathway, allowing the model to quantitatively reproduce the observed interaction effects. The continuous coupling between representations in the model also implies that modulation should be bidirectional, and model simulations provide specific predictions for complementary effects of saccade target selection on visual working memory. These predictions were empirically confirmed in a new experiment: Memory for a sample color was biased toward the color of a task-irrelevant saccade target object, demonstrating the bidirectional coupling between visual working memory and perceptual processing. PMID:25228628

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

PubMed

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

2011-03-04

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

The Effects of Block Size on the Performance of Coherent Caches in Shared-Memory Multiprocessors

DTIC Science & Technology

1993-05-01

increase with the bandwidth and latency. For those applications with poor spatial locality, the best choice of cache line size is determined by the...observation was used in the design of two schemes: LimitLESS di- rectories and Tag caches. LimitLESS directories [15] were designed for the ALEWIFE...small packets may be used to avoid network congestion. The most important factor influencing the choice of cache line size for a multipro- cessor is the

Development of a Low-Latency, High Data Rate, Differential GPS Relative Positioning System for UAV Formation Flight Control

DTIC Science & Technology

2006-09-01

spiral development cycle involved transporting the software processes from a Windows XP / MATLAB environment to a Linux / C++ environment. This...tested on. Additionally, in the case of the GUMSTIX PC boards, the LINUX operating system is burned into the read-only memory. Lastly, both PC-104 and...both the real-time environment and the post-processed en - vironment. When the system operates in real-time mode, an output file is generated which

Interpreter composition issues in the formal verification of a processor-memory module

NASA Technical Reports Server (NTRS)

Fura, David A.; Cohen, Gerald C.

1994-01-01

This report describes interpreter composition techniques suitable for the formal specification and verification of a processor-memory module using the HOL theorem proving system. The processor-memory module is a multichip subsystem within a fault-tolerant embedded system under development within the Boeing Defense and Space Group. Modeling and verification methods were developed that permit provably secure composition at the transaction-level of specification, significantly reducing the complexity of the hierarchical verification of the system.

Ethanol Reversal of Tolerance to the Respiratory Depressant Effects of Morphine

PubMed Central

Hill, Rob; Lyndon, Abi; Withey, Sarah; Roberts, Joanne; Kershaw, Yvonne; MacLachlan, John; Lingford-Hughes, Anne; Kelly, Eamonn; Bailey, Chris; Hickman, Matthew; Henderson, Graeme

2016-01-01

Opioids are the most common drugs associated with unintentional drug overdose. Death results from respiratory depression. Prolonged use of opioids results in the development of tolerance but the degree of tolerance is thought to vary between different effects of the drugs. Many opioid addicts regularly consume alcohol (ethanol), and post-mortem analyses of opioid overdose deaths have revealed an inverse correlation between blood morphine and ethanol levels. In the present study, we determined whether ethanol reduced tolerance to the respiratory depressant effects of opioids. Mice were treated with opioids (morphine, methadone, or buprenorphine) for up to 6 days. Respiration was measured in freely moving animals breathing 5% CO2 in air in plethysmograph chambers. Antinociception (analgesia) was measured as the latency to remove the tail from a thermal stimulus. Opioid tolerance was assessed by measuring the response to a challenge dose of morphine (10 mg/kg i.p.). Tolerance developed to the respiratory depressant effect of morphine but at a slower rate than tolerance to its antinociceptive effect. A low dose of ethanol (0.3 mg/kg) alone did not depress respiration but in prolonged morphine-treated animals respiratory depression was observed when ethanol was co-administered with the morphine challenge. Ethanol did not alter the brain levels of morphine. In contrast, in methadone- or buprenorphine-treated animals no respiratory depression was observed when ethanol was co-administered along with the morphine challenge. As heroin is converted to morphine in man, selective reversal of morphine tolerance by ethanol may be a contributory factor in heroin overdose deaths. PMID:26171718

Implementation of an experimental fault-tolerant memory system

NASA Technical Reports Server (NTRS)

Carter, W. C.; Mccarthy, C. E.

1976-01-01

The experimental fault-tolerant memory system described in this paper has been designed to enable the modular addition of spares, to validate the theoretical fault-secure and self-testing properties of the translator/corrector, to provide a basis for experiments using the new testing and correction processes for recovery, and to determine the practicality of such systems. The hardware design and implementation are described, together with methods of fault insertion. The hardware/software interface, including a restricted single error correction/double error detection (SEC/DED) code, is specified. Procedures are carefully described which, (1) test for specified physical faults, (2) ensure that single error corrections are not miscorrections due to triple faults, and (3) enable recovery from double errors.

A distributed fault-tolerant signal processor /FTSP/

NASA Astrophysics Data System (ADS)

Bonneau, R. J.; Evett, R. C.; Young, M. J.

1980-01-01

A digital fault-tolerant signal processor (FTSP), an example of a self-repairing programmable system is analyzed. The design configuration is discussed in terms of fault tolerance, system-level fault detection, isolation and common memory. Special attention is given to the FDIR (fault detection isolation and reconfiguration) logic, noting that the reconfiguration decisions are based on configuration, summary status, end-around tests, and north marker/synchro data. Several mechanisms of fault detection are described which initiate reconfiguration at different levels. It is concluded that the reliability of a signal processor can be significantly enhanced by the use of fault-tolerant techniques.

Perinatal exposure to bisphenol-A impairs spatial memory through upregulation of neurexin1 and neuroligin3 expression in male mouse brain.

PubMed

Kumar, Dhiraj; Thakur, Mahendra Kumar

2014-01-01

Bisphenol-A (BPA), a well known endocrine disruptor, impairs learning and memory in rodents. However, the underlying molecular mechanism of BPA induced impairment in learning and memory is not well known. As synaptic plasticity is the cellular basis of memory, the present study investigated the effect of perinatal exposure to BPA on the expression of synaptic proteins neurexin1 (Nrxn1) and neuroligin3 (Nlgn3), dendritic spine density and spatial memory in postnatal male mice. The pregnant mice were orally administered BPA (50 µg/kgbw/d) from gestation day (GD) 7 to postnatal day (PND) 21 and sesame oil was used as a vehicle control. In Morris water maze (MWM) test, BPA extended the escape latency time to locate the hidden platform in 8 weeks male mice. RT-PCR and Immunoblotting results showed significant upregulation of Nrxn1 and Nlgn3 expression in both cerebral cortex and hippocampus of 3 and 8 weeks male mice. This was further substantiated by in-situ hybridization and immunofluorescence techniques. BPA also significantly increased the density of dendritic spines in both regions, as analyzed by rapid Golgi staining. Thus our data suggest that perinatal exposure to BPA impairs spatial memory through upregulation of expression of synaptic proteins Nrxn1 and Nlgn3 and increased dendritic spine density in cerebral cortex and hippocampus of postnatal male mice.

Perinatal Exposure to Bisphenol-A Impairs Spatial Memory through Upregulation of Neurexin1 and Neuroligin3 Expression in Male Mouse Brain

PubMed Central

Kumar, Dhiraj; Thakur, Mahendra Kumar

2014-01-01

Bisphenol-A (BPA), a well known endocrine disruptor, impairs learning and memory in rodents. However, the underlying molecular mechanism of BPA induced impairment in learning and memory is not well known. As synaptic plasticity is the cellular basis of memory, the present study investigated the effect of perinatal exposure to BPA on the expression of synaptic proteins neurexin1 (Nrxn1) and neuroligin3 (Nlgn3), dendritic spine density and spatial memory in postnatal male mice. The pregnant mice were orally administered BPA (50 µg/kgbw/d) from gestation day (GD) 7 to postnatal day (PND) 21 and sesame oil was used as a vehicle control. In Morris water maze (MWM) test, BPA extended the escape latency time to locate the hidden platform in 8 weeks male mice. RT-PCR and Immunoblotting results showed significant upregulation of Nrxn1 and Nlgn3 expression in both cerebral cortex and hippocampus of 3 and 8 weeks male mice. This was further substantiated by in-situ hybridization and immunofluorescence techniques. BPA also significantly increased the density of dendritic spines in both regions, as analyzed by rapid Golgi staining. Thus our data suggest that perinatal exposure to BPA impairs spatial memory through upregulation of expression of synaptic proteins Nrxn1 and Nlgn3 and increased dendritic spine density in cerebral cortex and hippocampus of postnatal male mice. PMID:25330104

Protective effects of cultured and fermented ginseng extracts against scopolamine-induced memory loss in a mouse model.

PubMed

Han, Song-Hee; Kim, Sung-June; Yun, Young Won; Nam, Sang Yoon; Lee, Hu-Jang; Lee, Beom-Jun

2018-03-01

This study was performed to investigate the effect of a concentrate of fermented wild ginseng root culture (HLJG0701) on memory improvement in the scopolamine (SPL)-induced memory-deficient mouse model. Eight-week-old male ICR mice were used to evaluate the protective effect of HLJG0701 against the SPL-induced memory loss animal model. The Morris water maze test, which measures hippocampus-dependent learning ability, and the Y-maze test, a short-term memory assessment test, were performed and related markers were analyzed. HLJG0701-treated groups displayed significantly reduced acetylcholinesterase activity and increased acetylcholine level compared with the SPL-administered group (SPL-G) ( P <0.05). In the Y-maze test, the spontaneous alternation in al HLJG0711-treated groups was significantly increased compared with that in SPL-G ( P <0.05). In the Morris water maze test, the escape latency and time spent in the target quadrant in all HLJG0701-treated groups were significantly decreased and increased, respectively, compared with those in SPL-G ( P <0.05). In addition, the brain-derived neurotrophic factor level in groups treated with HLJG0701 300 and 600 mg/kg body weight was significantly increased compared with that in SPL-G ( P <0.05). These results suggest that the HLJG0701 may protect against memory loss by inhibiting acetylcholinesterase activity and preventing acetylcholine deficiency.

Factors Predicting Smoking in a Laboratory-Based Smoking-Choice Task

PubMed Central

Bold, Krysten W.; Yoon, Haewon; Chapman, Gretchen B.; McCarthy, Danielle E.

2013-01-01

This study aimed to expand the current understanding of smoking maintenance mechanisms by examining how putative relapse risk factors relate to a single behavioral smoking choice using a novel laboratory smoking-choice task. After 12 hours of nicotine deprivation, participants were exposed to smoking cues and given the choice between smoking up to two cigarettes in a 15-minute window or waiting and receiving four cigarettes after a delay of 45 minutes. Greater nicotine dependence, higher impulsivity, and lower distress tolerance were hypothesized to predict earlier and more intensive smoking. Out of 35 participants (n=9 female), 26 chose to smoke with a median time to a first puff of 1.22 minutes (standard deviation=2.62 min, range=0.03–10.62 min). Survival analyses examined latency to first puff, and results indicated that greater pre-task craving and smoking more cigarettes per day were significantly related to smoking sooner in the task. Greater behavioral disinhibition predicted shorter smoking latency in the first two minutes of the task, but not at a delay of more than two minutes. Lower distress tolerance (reporting greater regulation efforts to alleviate distress) was related to more puffs smoked and greater nicotine dependence was related to more time spent smoking in the task. This novel laboratory smoking-choice paradigm may be a useful laboratory analog for the choices smokers make during cessation attempts and may help identify factors that influence smoking lapses. PMID:23421357

Methylation-regulated decommissioning of multimeric PP2A complexes

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

Wu, Cheng-Guo; Zheng, Aiping; Jiang, Li

2017-12-01

Dynamic assembly/disassembly of signaling complexes are crucial for cellular functions. Specialized latency and activation chaperones control the biogenesis of protein phosphatase 2A (PP2A) holoenzymes that contain a common scaffold and catalytic subunits and a variable regulatory subunit. Here we show that the butterfly-shaped TIPRL (TOR signaling pathway regulator) makes highly integrative multibranching contacts with the PP2A catalytic subunit, selective for the unmethylated tail and perturbing/inactivating the phosphatase active site. TIPRL also makes unusual wobble contacts with the scaffold subunit, allowing TIPRL, but not the overlapping regulatory subunits, to tolerate disease-associated PP2A mutations, resulting in reduced holoenzyme assembly and enhanced inactivationmore » of mutant PP2A. Strikingly, TIPRL and the latency chaperone, α4, coordinate to disassemble active holoenzymes into latent PP2A, strictly controlled by methylation. Our study reveals a mechanism for methylation-responsive inactivation and holoenzyme disassembly, illustrating the complexity of regulation/signaling, dynamic complex disassembly, and disease mutations in cancer and intellectual disability.« less

Pre-training Catechin gavage prevents memory impairment induced by intracerebroventricular streptozotocin in rats.

PubMed

Zamani, Marzieh; Rohampour, Kambiz; Zeraati, Maryam; Hosseinmardi, Narges; Kazemian, Mostafa M

2015-07-01

To evaluate the effects of Catechin (CAT) on memory acquisition and retrieval in the animal model of sporadic alzheimer`s disease (sAD) induced by intracerebroventricular (icv) injection of streptozotocin (STZ) in passive avoidance memory test. Thirty adult rats were divided into 5 experimental groups (n=6). Animals were treated by icv saline/STZ (3 mg/kg) injection at day one and 3 after cannulation. The STZ+CAT group received 40 mg/kg CAT by daily gavages for 10 days, after icv STZ treatment and before training. The step-through latency (STL) and time spent in the dark compartment (TDC) were evaluated to examine the memory acquisition and retrieval. All tests were performed in Qom University of Medical Sciences, Qom, Iran, from April to December 2013. The STZ treatment significantly decreased STL and increased the number of entries to the dark compartment on the training day. It also increased TDC, on day one and 7 after training. Pre-training gavage of CAT reversed the STL significantly (p=0.027). The CAT treatment also decreased the TDC in both early and late retrieval, in respect to STZ group. This data suggests that CAT as an antioxidant could improve both memory acquisition and retrieval in the animal model of sAD.

Intrahippocampal administration of an antibody against the HNK-1 carbohydrate impairs memory consolidation in an inhibitory learning task in mice.

PubMed

Strekalova, T; Wotjak, C T; Schachner, M

2001-06-01

Many cell adhesion molecules express the HNK-1 carbohydrate involved in formation and functioning of synapses. To assess its role in learning, we injected the monoclonal HNK-1 antibody or nonimmune IgG into the hippocampus of C57BL/6J mice 1 h after training in a step-down avoidance task. In animals treated with the HNK-1 antibody, latencies of step down in a recall session 48 h after injection did not change compared to training values and were significantly shorter versus IgG-treated controls, which acquired the task normally. Similar differences between the two treatments were also observed after a stronger training protocol in a step-down avoidance paradigm. The HNK-1 antibody was effective only when injected 1 h, but not 48 h after training, thus affecting memory consolidation but not memory recall itself. The HNK-1 antibody impaired memory also in tenascin-R knock-out mice, indicating that extracellular matrix molecule tenascin-R, one of the carriers of the HNK-1epitope in the hippocampus, does not mediate the function of the HNK-1 carbohydrate in this task. Our observations show that the HNK-1 carbohydrate is critically involved in memory consolidation in hippocampus-dependent learning in mammals. Copyright 2001 Academic Press.

Central ghrelin increases anxiety in the Open Field test and impairs retention memory in a passive avoidance task in neonatal chicks.

PubMed

Carvajal, Pedro; Carlini, Valeria P; Schiöth, Helgi B; de Barioglio, Susana R; Salvatierra, Nancy A

2009-05-01

Ghrelin (Grh) is an endogenous ligand for the growth hormone secretagogue receptor. Although Ghr stimulates feeding in rats, it inhibits feeding in neonatal chicks. However, little is known about other central behavioral effects of Ghr. Therefore, we investigated the Ghr effects, injected intracerebroventricularly, on anxiety and memory retention of neonatal chicks in an Open Field test and in a one-trial passive avoidance task, respectively. In the Open Field test, the administration of Ghr in a dose-dependent manner increased the latency to ambulate but decreased ambulation activity, indicating an anxiogenic effect. Furthermore, chicks trained on a passive avoidance task and injected with a dose of 30pmol of Ghr immediately after training showed an impairment of memory retention. However, there were no significant effects on the number of pecks during the pretraining, training, retention and discrimination. In addition, different doses of Ghr produced an inhibition in food intake at different times after injection. Our results indicate that Ghr induces anxiogenesis in chicks. Moreover, we have shown for the first time that Ghr can decrease memory retention in a non-mammalian species, suggesting that Ghr may play an important role in the processes of memory retention in birds.

The ampakine, Org 26576, bolsters early spatial reference learning and retrieval in the Morris water maze: a subchronic, dose-ranging study in rats.

PubMed

Hamlyn, Eugene; Brand, Linda; Shahid, Mohammed; Harvey, Brian H

2009-10-01

Ampakines have shown beneficial effects on cognition in selected animal models of learning. However, their ability to modify long-term spatial memory tasks has not been studied yet. This would lend credence to their possible value in treating disorders of cognition. We evaluated the actions of subchronic Org 26576 administration on spatial reference memory performance in the 5-day Morris water maze task in male Sprague-Dawley rats, at doses of 1, 3 and 10 mg/kg twice daily through intraperitoneal injection over 12 days. Org 26576 exerted a dose and time-dependent effect on spatial learning, with dosages of 3 and 10 mg/kg significantly enhancing acquisition on day 1. Globally, escape latency decreased significantly as the training days progressed in the saline and Org 26576-treated groups, indicating that significant and equal learning had taken place over the learning period. However, at the end of the learning period, all doses of Org 26576 significantly improved spatial memory storage/retrieval without confounding effects in the cued version of the task. Org 26576 offers early phase spatial memory benefits in rats, but particularly enhances search accuracy during reference memory retrieval. These results support its possible utility in treating disorders characterized by deficits in cognitive performance.

Combined methods of tolerance increasing for embedded SRAM

NASA Astrophysics Data System (ADS)

Shchigorev, L. A.; Shagurin, I. I.

2016-10-01

The abilities of combined use of different methods of fault tolerance increasing for SRAM such as error detection and correction codes, parity bits, and redundant elements are considered. Area penalties due to using combinations of these methods are investigated. Estimation is made for different configurations of 4K x 128 RAM memory block for 28 nm manufacturing process. Evaluation of the effectiveness of the proposed combinations is also reported. The results of these investigations can be useful for designing fault-tolerant “system on chips”.

Development and evaluation of a fault-tolerant multiprocessor (FTMP) computer. Volume 1: FTMP principles of operation

NASA Technical Reports Server (NTRS)

Smith, T. B., Jr.; Lala, J. H.

1983-01-01

The basic organization of the fault tolerant multiprocessor, (FTMP) is that of a general purpose homogeneous multiprocessor. Three processors operate on a shared system (memory and I/O) bus. Replication and tight synchronization of all elements and hardware voting is employed to detect and correct any single fault. Reconfiguration is then employed to repair a fault. Multiple faults may be tolerated as a sequence of single faults with repair between fault occurrences.

Loganin enhances long-term potentiation and recovers scopolamine-induced learning and memory impairments.

PubMed

Hwang, Eun-Sang; Kim, Hyun-Bum; Lee, Seok; Kim, Min-Ji; Lee, Sung-Ok; Han, Seung-Moo; Maeng, Sungho; Park, Ji-Ho

2017-03-15

Although the incidence rate of dementia is rapidly growing in the aged population, therapeutic and preventive reagents are still suboptimal. Various model systems are used for the development of such reagents in which scopolamine is one of the favorable pharmacological tools widely applied. Loganin is a major iridoid glycoside obtained from Corni fructus (Cornusofficinalis et Zucc) and demonstrated to have anti-inflammatory, anti-tumor and osteoporosis prevention effects. It has also been found to attenuate Aβ-induced inflammatory reactions and ameliorate memory deficits induced by scopolamine. However, there has been limited information available on how loganin affects learning and memory both electrophysiologically and behaviorally. To assess its effect on learning and memory, we investigated the influence of acute loganin administration on long-term potentiation (LTP) using organotypic cultured hippocampal tissues. In addition, we measured the effects of loganin on the behavior performance related to avoidance memory, short-term spatial navigation memory and long-term spatial learning and memory in the passive avoidance, Y-maze, and Morris water maze learning paradigms, respectively. Loganin dose-dependently increased the total activity of fEPSP after high frequency stimulation and attenuated scopolamine-induced blockade of fEPSP in the hippocampal CA1 area. In accordance with these findings, loganin behaviorally attenuated scopolamine-induced shortening of step-through latency in the passive avoidance test, reduced the percent alternation in the Y-maze, and increased memory retention in the Morris water maze test. These results indicate that loganin can effectively block cholinergic muscarinic receptor blockade -induced deterioration of LTP and memory related behavioral performance. Based on these findings, loganin may aid in the prevention and treatment of Alzheimer's disease and learning and memory-deficit disorders in the future. Copyright © 2017 Elsevier Inc. All rights reserved.

Scalable printed electronics: an organic decoder addressing ferroelectric non-volatile memory

PubMed Central

Ng, Tse Nga; Schwartz, David E.; Lavery, Leah L.; Whiting, Gregory L.; Russo, Beverly; Krusor, Brent; Veres, Janos; Bröms, Per; Herlogsson, Lars; Alam, Naveed; Hagel, Olle; Nilsson, Jakob; Karlsson, Christer

2012-01-01

Scalable circuits of organic logic and memory are realized using all-additive printing processes. A 3-bit organic complementary decoder is fabricated and used to read and write non-volatile, rewritable ferroelectric memory. The decoder-memory array is patterned by inkjet and gravure printing on flexible plastics. Simulation models for the organic transistors are developed, enabling circuit designs tolerant of the variations in printed devices. We explain the key design rules in fabrication of complex printed circuits and elucidate the performance requirements of materials and devices for reliable organic digital logic. PMID:22900143

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

PubMed

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.

The Effects of Feature-Based Priming and Visual Working Memory on Oculomotor Capture.

PubMed

Silvis, Jeroen D; Belopolsky, Artem V; Murris, Jozua W I; Donk, Mieke

2015-01-01

Recently, it has been demonstrated that objects held in working memory can influence rapid oculomotor selection. This has been taken as evidence that perceptual salience can be modified by active working memory representations. The goal of the present study was to examine whether these results could also be caused by feature-based priming. In two experiments, participants were asked to saccade to a target line segment of a certain orientation that was presented together with a to-be-ignored distractor. Both objects were given a task-irrelevant color that varied per trial. In a secondary task, a color had to be memorized, and that color could either match the color of the target, match the color of the distractor, or it did not match the color of any of the objects in the search task. The memory task was completed either after the search task (Experiment 1), or before it (Experiment 2). The results showed that in both experiments the memorized color biased oculomotor selection. Eye movements were more frequently drawn towards objects that matched the memorized color, irrespective of whether the memory task was completed after (Experiment 1) or before (Experiment 2) the search task. This bias was particularly prevalent in short-latency saccades. The results show that early oculomotor selection performance is not only affected by properties that are actively maintained in working memory but also by those previously memorized. Both working memory and feature priming can cause early biases in oculomotor selection.

The Effects of Feature-Based Priming and Visual Working Memory on Oculomotor Capture

PubMed Central

Silvis, Jeroen D.; Belopolsky, Artem V.; Murris, Jozua W. I.; Donk, Mieke

2015-01-01

Recently, it has been demonstrated that objects held in working memory can influence rapid oculomotor selection. This has been taken as evidence that perceptual salience can be modified by active working memory representations. The goal of the present study was to examine whether these results could also be caused by feature-based priming. In two experiments, participants were asked to saccade to a target line segment of a certain orientation that was presented together with a to-be-ignored distractor. Both objects were given a task-irrelevant color that varied per trial. In a secondary task, a color had to be memorized, and that color could either match the color of the target, match the color of the distractor, or it did not match the color of any of the objects in the search task. The memory task was completed either after the search task (Experiment 1), or before it (Experiment 2). The results showed that in both experiments the memorized color biased oculomotor selection. Eye movements were more frequently drawn towards objects that matched the memorized color, irrespective of whether the memory task was completed after (Experiment 1) or before (Experiment 2) the search task. This bias was particularly prevalent in short-latency saccades. The results show that early oculomotor selection performance is not only affected by properties that are actively maintained in working memory but also by those previously memorized. Both working memory and feature priming can cause early biases in oculomotor selection. PMID:26566137

Odor-enriched environment rescues long-term social memory, but does not improve olfaction in social isolated adult mice.

PubMed

Gusmão, Isabela D; Monteiro, Brisa M M; Cornélio, Guilherme O S; Fonseca, Cristina S; Moraes, Márcio F D; Pereira, Grace S

2012-03-17

Prolonged permanence of animals under social isolation (SI) arouses a variety of psychological symptoms like aggression, stress, anxiety and depression. However, short-term SI is commonly used to evaluate social memory. Interestingly, the social memory cannot be accessed with delays higher than 30min in SI mice. Our hypothesis is that SI with intermediate duration, like one week (1w), impairs the long-term storage of new social information (S-LTM), without affecting anxiety or other types of memories, because the SI compromises the olfactory function of the animal. Our results demonstrated that SI impaired S-LTM, without affecting other kinds of memory or anxiety. In addition, the SI increased the latency in the buried-food finding task, but did not affect the habituation or the discrimination of odors. Next, we postulated that if continuous input to the olfactory system is fundamental for the maintenance of the olfactory function and social memory persistence, isolated mice under odor-enriched environment (OEE) should behave like group-housed (GH) animals. In fact, the OEE prevented the S-LTM deficit imposed by the SI. However, OEE did not restore the SI mice olfaction to the GH mice level. Our results suggest that SI modulates olfaction and social memory persistence, probably, by independent mechanisms. We also showed for the first time that OEE rescued S-LTM in SI mice through a mechanism not necessarily involved with olfaction. Copyright © 2011 Elsevier B.V. All rights reserved.

A Cerebellar-model Associative Memory as a Generalized Random-access Memory

NASA Technical Reports Server (NTRS)

Kanerva, Pentti

1989-01-01

A versatile neural-net model is explained in terms familiar to computer scientists and engineers. It is called the sparse distributed memory, and it is a random-access memory for very long words (for patterns with thousands of bits). Its potential utility is the result of several factors: (1) a large pattern representing an object or a scene or a moment can encode a large amount of information about what it represents; (2) this information can serve as an address to the memory, and it can also serve as data; (3) the memory is noise tolerant--the information need not be exact; (4) the memory can be made arbitrarily large and hence an arbitrary amount of information can be stored in it; and (5) the architecture is inherently parallel, allowing large memories to be fast. Such memories can become important components of future computers.

Effects of Chinese herbal medicine Yinsiwei compound on spatial learning and memory ability and the ultrastructure of hippocampal neurons in a rat model of sporadic Alzheimer disease.

PubMed

Diwu, Yong-chang; Tian, Jin-zhou; Shi, Jing

2011-02-01

To study the effects of Chinese herbal medicine Yinsiwei compound (YSW) on spatial learning and memory ability in rats with sporadic Alzheimer disease (SAD) and the ultrastructural basis of the hippocampal neurons. A rat model of SAD was established by intracerebroventricular injection of streptozotocin. The rats were divided into six groups: sham-operation group, model group, donepezil control group, and YSW low, medium and high dose groups. Drug interventions were started on the 21st day after modeling and each treatment group was given the corresponding drugs by gavage for two months. Meanwhile, the model group and the sham-operation group were given the same volume of distilled water by gavage once a day for two months. The Morris water maze was adopted to test spatial learning and memory ability of the rats. The place navigation test and the spatial probe test were conducted. The escape latency, total swimming distance and swimming time in the target quadrant of the rats were recorded. Also, the hippocampus tissues of rats were taken out and the ultrastructure of hippocampus neurons were observed by an electron microscope. In the place navigation test, compared with the model group, the mean escape latency and the total swimming distance of the donepezil group and the YSW low, medium and high dose groups were significantly shortened (P<0.05 or P<0.01). In the space probe test, the swimming time of each treatment group in the target quadrant was significantly longer than that of the model group (P<0.05 or P<0.01). For most of the test period, the donepezil group had no significant change compared with the YSW low, medium and high dose groups, respectively. The ultrastructure of the hippocampus neurons under the electron microscope also confirmed the efficacy of the drug treatment. Chinese herbal medicine YSW compound can improve spatial learning and memory impairment of rats with SAD. The ultrastructural basis may be that it can protect the microtubule structures of hippocampal neurons and prevent nerve axons from being damaged.

Autonomous Congestion Control in Delay-Tolerant Networks

NASA Technical Reports Server (NTRS)

Burleigh, Scott C.; Jennings, Esther H.

2005-01-01

Congestion control is an important feature that directly affects network performance. Network congestion may cause loss of data or long delays. Although this problem has been studied extensively in the Internet, the solutions for Internet congestion control do not apply readily to challenged network environments such as Delay Tolerant Networks (DTN) where end-to-end connectivity may not exist continuously and latency can be high. In DTN, end-to-end rate control is not feasible. This calls for congestion control mechanisms where the decisions can be made autonomously with local information only. We use an economic pricing model and propose a rule-based congestion control mechanism where each router can autonomously decide on whether to accept a bundle (data) based on local information such as available storage and the value and risk of accepting the bundle (derived from historical statistics).

Recent advances in CMV tropism, latency, and diagnosis during aging.

PubMed

Leng, Sean X; Kamil, Jeremy; Purdy, John G; Lemmermann, Niels A; Reddehase, Matthias J; Goodrum, Felicia D

2017-06-01

Human cytomegalovirus (CMV) is one of the largest viruses known to cause human diseases. Chronic CMV infection, as defined by anti-CMV IgG serology, increases with age and is highly prevalent in older adults. It has complex biology with significant immunologic and health consequences. This article aims to summarize research findings presented at the 6th International Workshop on CMV and Immunosenescence that relate to advances in the areas of CMV tropism, latency, CMV manipulation of cell metabolism, and T cell memory inflation, as well as novel diagnostic evaluation and translational research of chronic CMV infection in older adults. Information summarized here represents the current state of knowledge in these important fields. Investigators have also identified a number of areas that deserve further and more in-depth investigation, including building more precise parallels between mouse CMV (mCMV) and human CMV (HCMV) research. It is hoped that this article will also stimulate engaging discussion on strategies and direction to advance the science to the next level.

REM Sleep Behavior Disorder and Narcoleptic Features in Anti–Ma2-associated Encephalitis

PubMed Central

Compta, Yaroslau; Iranzo, Alex; Santamaría, Joan; Casamitjana, Roser; Graus, Francesc

2007-01-01

A 69-year-old man with anti-Ma2 paraneoplastic encephalitis presented with subacute onset of severe hypersomnia, memory loss, parkinsonism, and gaze palsy. A brain magnetic resonance imaging study showed bilateral damage in the dorsolateral midbrain, amygdala, and paramedian thalami. Videopolysomnography disclosed rapid eye movement (REM) sleep behavior disorder, and a Multiple Sleep Latency Test showed a mean sleep latency of 7 minutes and 4 sleep-onset REM periods. The level of hypocretin-1 in the cerebrospinal fluid was low (49 pg/mL). This observation illustrates that REM sleep behavior disorder and narcoleptic features are 2 REM-sleep abnormalities that (1) may share the same autoimmune-mediated origin affecting the brainstem, limbic, and diencephalic structures and (2) may occur in the setting of the paraneoplastic anti–Ma2-associated encephalitis. Citation: Compta Y; Iranzo A; Santamaría J et al. REM Sleep Behavior Disorder and Narcoleptic Features in Anti–Ma2-associated Encephalitis. SLEEP 2007;30(6):767-769. PMID:17580598

Determinants of naming latencies, object comprehension times, and new norms for the Russian standardized set of the colorized version of the Snodgrass and Vanderwart pictures.

PubMed

Bonin, Patrick; Guillemard-Tsaparina, Diana; Méot, Alain

2013-09-01

We report object-naming and object recognition times collected from Russian native speakers for the colorized version of the Snodgrass and Vanderwart (Journal of Experimental Psychology: Human Learning and Memory 6:174-215, 1980) pictures (Rossion & Pourtois, Perception 33:217-236, 2004). New norms for image variability, body-object interaction [BOI], and subjective frequency collected in Russian, as well as new name agreement scores for the colorized pictures in French, are also reported. In both object-naming and object comprehension times, the name agreement, image agreement, and age-of-acquisition variables made significant independent contributions. Objective word frequency was reliable in object-naming latencies only. The variables of image variability, BOI, and subjective frequency were not significant in either object naming or object comprehension. Finally, imageability was reliable in both tasks. The new norms and object-naming and object recognition times are provided as supplemental materials.

RXIO: Design and implementation of high performance RDMA-capable GridFTP

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

Tian, Yuan; Yu, Weikuan; Vetter, Jeffrey S.

2011-12-21

For its low-latency, high bandwidth, and low CPU utilization, Remote Direct Memory Access (RDMA) has established itself as an effective data movement technology in many networking environments. However, the transport protocols of grid run-time systems, such as GridFTP in Globus, are not yet capable of utilizing RDMA. In this study, we examine the architecture of GridFTP for the feasibility of enabling RDMA. An RDMA-capable XIO (RXIO) framework is designed and implemented to extend its XIO system and match the characteristics of RDMA. Our experimental results demonstrate that RDMA can significantly improve the performance of GridFTP, reducing the latency by 32%more » and increasing the bandwidth by more than three times. In achieving such performance improvements, RDMA dramatically cuts down CPU utilization of GridFTP clients and servers. In conclusion, these results demonstrate that RXIO can effectively exploit the benefits of RDMA for GridFTP. It offers a good prototype to further leverage GridFTP on wide-area RDMA networks.« less

A smart checkpointing scheme for improving the reliability of clustering routing protocols.

PubMed

Min, Hong; Jung, Jinman; Kim, Bongjae; Cho, Yookun; Heo, Junyoung; Yi, Sangho; Hong, Jiman

2010-01-01

In wireless sensor networks, system architectures and applications are designed to consider both resource constraints and scalability, because such networks are composed of numerous sensor nodes with various sensors and actuators, small memories, low-power microprocessors, radio modules, and batteries. Clustering routing protocols based on data aggregation schemes aimed at minimizing packet numbers have been proposed to meet these requirements. In clustering routing protocols, the cluster head plays an important role. The cluster head collects data from its member nodes and aggregates the collected data. To improve reliability and reduce recovery latency, we propose a checkpointing scheme for the cluster head. In the proposed scheme, backup nodes monitor and checkpoint the current state of the cluster head periodically. We also derive the checkpointing interval that maximizes reliability while using the same amount of energy consumed by clustering routing protocols that operate without checkpointing. Experimental comparisons with existing non-checkpointing schemes show that our scheme reduces both energy consumption and recovery latency.

NaNet: a configurable NIC bridging the gap between HPC and real-time HEP GPU computing

NASA Astrophysics Data System (ADS)

Lonardo, A.; Ameli, F.; Ammendola, R.; Biagioni, A.; Cotta Ramusino, A.; Fiorini, M.; Frezza, O.; Lamanna, G.; Lo Cicero, F.; Martinelli, M.; Neri, I.; Paolucci, P. S.; Pastorelli, E.; Pontisso, L.; Rossetti, D.; Simeone, F.; Simula, F.; Sozzi, M.; Tosoratto, L.; Vicini, P.

2015-04-01

NaNet is a FPGA-based PCIe Network Interface Card (NIC) design with GPUDirect and Remote Direct Memory Access (RDMA) capabilities featuring a configurable and extensible set of network channels. The design currently supports both standard—Gbe (1000BASE-T) and 10GbE (10Base-R)—and custom—34 Gbps APElink and 2.5 Gbps deterministic latency KM3link—channels, but its modularity allows for straightforward inclusion of other link technologies. The GPUDirect feature combined with a transport layer offload module and a data stream processing stage makes NaNet a low-latency NIC suitable for real-time GPU processing. In this paper we describe the NaNet architecture and its performances, exhibiting two of its use cases: the GPU-based low-level trigger for the RICH detector in the NA62 experiment at CERN and the on-/off-shore data transport system for the KM3NeT-IT underwater neutrino telescope.

Graphical processors for HEP trigger systems

NASA Astrophysics Data System (ADS)

Ammendola, R.; Biagioni, A.; Chiozzi, S.; Cotta Ramusino, A.; Di Lorenzo, S.; Fantechi, R.; Fiorini, M.; Frezza, O.; Lamanna, G.; Lo Cicero, F.; Lonardo, A.; Martinelli, M.; Neri, I.; Paolucci, P. S.; Pastorelli, E.; Piandani, R.; Pontisso, L.; Rossetti, D.; Simula, F.; Sozzi, M.; Vicini, P.

2017-02-01

General-purpose computing on GPUs is emerging as a new paradigm in several fields of science, although so far applications have been tailored to employ GPUs as accelerators in offline computations. With the steady decrease of GPU latencies and the increase in link and memory throughputs, time is ripe for real-time applications using GPUs in high-energy physics data acquisition and trigger systems. We will discuss the use of online parallel computing on GPUs for synchronous low level trigger systems, focusing on tests performed on the trigger of the CERN NA62 experiment. Latencies of all components need analysing, networking being the most critical. To keep it under control, we envisioned NaNet, an FPGA-based PCIe Network Interface Card (NIC) enabling GPUDirect connection. Moreover, we discuss how specific trigger algorithms can be parallelised and thus benefit from a GPU implementation, in terms of increased execution speed. Such improvements are particularly relevant for the foreseen LHC luminosity upgrade where highly selective algorithms will be crucial to maintain sustainable trigger rates with very high pileup.

A Smart Checkpointing Scheme for Improving the Reliability of Clustering Routing Protocols

PubMed Central

Min, Hong; Jung, Jinman; Kim, Bongjae; Cho, Yookun; Heo, Junyoung; Yi, Sangho; Hong, Jiman

2010-01-01

In wireless sensor networks, system architectures and applications are designed to consider both resource constraints and scalability, because such networks are composed of numerous sensor nodes with various sensors and actuators, small memories, low-power microprocessors, radio modules, and batteries. Clustering routing protocols based on data aggregation schemes aimed at minimizing packet numbers have been proposed to meet these requirements. In clustering routing protocols, the cluster head plays an important role. The cluster head collects data from its member nodes and aggregates the collected data. To improve reliability and reduce recovery latency, we propose a checkpointing scheme for the cluster head. In the proposed scheme, backup nodes monitor and checkpoint the current state of the cluster head periodically. We also derive the checkpointing interval that maximizes reliability while using the same amount of energy consumed by clustering routing protocols that operate without checkpointing. Experimental comparisons with existing non-checkpointing schemes show that our scheme reduces both energy consumption and recovery latency. PMID:22163389

Sex effects on spatial learning but not on spatial memory retrieval in healthy young adults.

PubMed

Piber, Dominique; Nowacki, Jan; Mueller, Sven C; Wingenfeld, Katja; Otte, Christian

2018-01-15

Sex differences have been found in spatial learning and spatial memory, with several studies indicating that males outperform females. We tested in the virtual Morris Water Maze (vMWM) task, whether sex differences in spatial cognitive processes are attributable to differences in spatial learning or spatial memory retrieval in a large student sample. We tested 90 healthy students (45 women and 45 men) with a mean age of 23.5 years (SD=3.5). Spatial learning and spatial memory retrieval were measured by using the vMWM task, during which participants had to search a virtual pool for a hidden platform, facilitated by visual cues surrounding the pool. Several learning trials assessed spatial learning, while a separate probe trial assessed spatial memory retrieval. We found a significant sex effect during spatial learning, with males showing shorter latency and shorter path length, as compared to females (all p<0.001). Yet, there was no significant sex effect in spatial memory retrieval (p=0.615). Furthermore, post-hoc analyses revealed significant sex differences in spatial search strategies (p<0.05), but no difference in the number of platform crossings (p=0.375). Our results indicate that in healthy young adults, males show faster spatial learning in a virtual environment, as compared to females. Interestingly, we found no significant sex differences during spatial memory retrieval. Our study raises the question, whether men and women use different learning strategies, which nevertheless result in equal performances of spatial memory retrieval. Copyright © 2017 Elsevier B.V. All rights reserved.

Initial Performance Results on IBM POWER6

NASA Technical Reports Server (NTRS)

Saini, Subbash; Talcott, Dale; Jespersen, Dennis; Djomehri, Jahed; Jin, Haoqiang; Mehrotra, Piysuh

2008-01-01

The POWER5+ processor has a faster memory bus than that of the previous generation POWER5 processor (533 MHz vs. 400 MHz), but the measured per-core memory bandwidth of the latter is better than that of the former (5.7 GB/s vs. 4.3 GB/s). The reason for this is that in the POWER5+, the two cores on the chip share the L2 cache, L3 cache and memory bus. The memory controller is also on the chip and is shared by the two cores. This serializes the path to memory. For consistently good performance on a wide range of applications, the performance of the processor, the memory subsystem, and the interconnects (both latency and bandwidth) should be balanced. Recognizing this, IBM has designed the Power6 processor so as to avoid the bottlenecks due to the L2 cache, memory controller and buffer chips of the POWER5+. Unlike the POWER5+, each core in the POWER6 has its own L2 cache (4 MB - double that of the Power5+), memory controller and buffer chips. Each core in the POWER6 runs at 4.7 GHz instead of 1.9 GHz in POWER5+. In this paper, we evaluate the performance of a dual-core Power6 based IBM p6-570 system, and we compare its performance with that of a dual-core Power5+ based IBM p575+ system. In this evaluation, we have used the High- Performance Computing Challenge (HPCC) benchmarks, NAS Parallel Benchmarks (NPB), and four real-world applications--three from computational fluid dynamics and one from climate modeling.

The memory state heuristic: A formal model based on repeated recognition judgments.

PubMed

Castela, Marta; Erdfelder, Edgar

2017-02-01

The recognition heuristic (RH) theory predicts that, in comparative judgment tasks, if one object is recognized and the other is not, the recognized one is chosen. The memory-state heuristic (MSH) extends the RH by assuming that choices are not affected by recognition judgments per se, but by the memory states underlying these judgments (i.e., recognition certainty, uncertainty, or rejection certainty). Specifically, the larger the discrepancy between memory states, the larger the probability of choosing the object in the higher state. The typical RH paradigm does not allow estimation of the underlying memory states because it is unknown whether the objects were previously experienced or not. Therefore, we extended the paradigm by repeating the recognition task twice. In line with high threshold models of recognition, we assumed that inconsistent recognition judgments result from uncertainty whereas consistent judgments most likely result from memory certainty. In Experiment 1, we fitted 2 nested multinomial models to the data: an MSH model that formalizes the relation between memory states and binary choices explicitly and an approximate model that ignores the (unlikely) possibility of consistent guesses. Both models provided converging results. As predicted, reliance on recognition increased with the discrepancy in the underlying memory states. In Experiment 2, we replicated these results and found support for choice consistency predictions of the MSH. Additionally, recognition and choice latencies were in agreement with the MSH in both experiments. Finally, we validated critical parameters of our MSH model through a cross-validation method and a third experiment. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Fault tolerant function of dynamic refreshing holographic memory with shutter-less optical feedback circuit

NASA Astrophysics Data System (ADS)

Okamoto, Atsushi; Ito, Terumasa; Bunsen, Masatoshi; Takayama, Yoshihisa

2005-11-01

The optical system, consisting of two photorefractive memories and a shutter-less optical feedback circuit, will be demonstrated to function as data mirroring. This function is known to automatically detect the data dropout and restore data, using unimpaired data in another memory, in the event that part or all of the data in either of them were lost for some reason. This memory system also can cope with a damaged hologram, a result of reading beams, which is a disadvantage of rewritable photorefractive memory, to ensure non-destructive holographic reading. It can be achieved by using no electronic circuits or mechanical structures; our optical experimental method in particular obtains this basic action.

A Fault-Tolerant Radiation-Robust Mass Storage Concept for Highly Scaled Flash Memory

NASA Astrophysics Data System (ADS)

Fuchs, Cristian M.; Trinitis, Carsten; Appel, Nicolas; Langer, Martin

2015-09-01

Future spacemissions will require vast amounts of data to be stored and processed aboard spacecraft. While satisfying operational mission requirements, storage systems must guarantee data integrity and recover damaged data throughout the mission. NAND-flash memories have become popular for space-borne high performance mass memory scenarios, though future storage concepts will rely upon highly scaled flash or other memory technologies. With modern flash memory, single bit erasure coding and RAID based concepts are insufficient. Thus, a fully run-time configurable, high performance, dependable storage concept, requiring a minimal set of logic or software. The solution is based on composite erasure coding and can be adjusted for altered mission duration or changing environmental conditions.

Aqueous Extract of Black Maca (Lepidium meyenii) on Memory Impairment Induced by Ovariectomy in Mice

PubMed Central

Rubio, Julio; Qiong, Wang; Liu, Xinmin; Jiang, Zhen; Dang, Haixia; Chen, Shi-Lin; Gonzales, Gustavo F.

2011-01-01

The present study aims to test two different doses of aqueous extract of black maca on learning and memory in ovariectomized (OVX) mice and their relation with malonalehyde (MDA), acetylcholinesterase (Ache) and monoamine oxidase (MAO) brain levels. Female mice were divided into five groups: (i) naive (control), (ii) sham, (iii) OVX mice and OVX mice treated with (iv) 0.50 g kg−1 and (v) 2.00 g kg−1 black maca. Mice were orally treated with distilled water or black maca during 35 days starting 7 days after surgery. Memory and learning were assessed using the water Morris maze (from day 23–27) and the step-down avoidance test (days 34 and 35). At the end of each treatment, mice were sacrificed by decapitation and brains were dissected out for MDA, Ache and MAO determinations. Black maca (0.5 and 2.0 g/kg) increased step-down latency when compared to OVX control mice. Black maca decreased MDA and Ache levels in OVX mice; whereas, no differences were observed in MAO levels. Finally, black maca improved experimental memory impairment induced by ovariectomy, due in part, by its antioxidant and Ache inhibitory activities. PMID:18955369

Aqueous Extract of Black Maca (Lepidium meyenii) on Memory Impairment Induced by Ovariectomy in Mice.

PubMed

Rubio, Julio; Qiong, Wang; Liu, Xinmin; Jiang, Zhen; Dang, Haixia; Chen, Shi-Lin; Gonzales, Gustavo F

2011-01-01

The present study aims to test two different doses of aqueous extract of black maca on learning and memory in ovariectomized (OVX) mice and their relation with malonalehyde (MDA), acetylcholinesterase (Ache) and monoamine oxidase (MAO) brain levels. Female mice were divided into five groups: (i) naive (control), (ii) sham, (iii) OVX mice and OVX mice treated with (iv) 0.50 g kg(-1) and (v) 2.00 g kg(-1) black maca. Mice were orally treated with distilled water or black maca during 35 days starting 7 days after surgery. Memory and learning were assessed using the water Morris maze (from day 23-27) and the step-down avoidance test (days 34 and 35). At the end of each treatment, mice were sacrificed by decapitation and brains were dissected out for MDA, Ache and MAO determinations. Black maca (0.5 and 2.0 g/kg) increased step-down latency when compared to OVX control mice. Black maca decreased MDA and Ache levels in OVX mice; whereas, no differences were observed in MAO levels. Finally, black maca improved experimental memory impairment induced by ovariectomy, due in part, by its antioxidant and Ache inhibitory activities.

Memory Deficit Recovery after Chronic Vanadium Exposure in Mice

PubMed Central

Folarin, Oluwabusayo; Olopade, Funmilayo; Onwuka, Silas; Olopade, James

2016-01-01

Vanadium is a transitional metal with an ability to generate reactive oxygen species in the biological system. This work was designed to assess memory deficits in mice chronically exposed to vanadium. A total of 132 male BALB/c mice (4 weeks old) were used for the experiment and were divided into three major groups of vanadium treated, matched controls, and animals exposed to vanadium for three months and thereafter vanadium was withdrawn. Animals were tested using Morris water maze and forelimb grip test at 3, 6, 9, and 12 months of age. The results showed that animals across the groups showed no difference in learning but had significant loss in memory abilities after 3 months of vanadium exposure and this trend continued in all vanadium-exposed groups relative to the controls. Animals exposed to vanadium for three months recovered significantly only 9 months after vanadium withdrawal. There was no significant difference in latency to fall in the forelimb grip test between vanadium-exposed groups and the controls in all age groups. In conclusion, we have shown that chronic administration of vanadium in mice leads to memory deficit which is reversible but only after a long period of vanadium withdrawal. PMID:26962395

Memory Deficit Recovery after Chronic Vanadium Exposure in Mice.

PubMed

Folarin, Oluwabusayo; Olopade, Funmilayo; Onwuka, Silas; Olopade, James

2016-01-01

Vanadium is a transitional metal with an ability to generate reactive oxygen species in the biological system. This work was designed to assess memory deficits in mice chronically exposed to vanadium. A total of 132 male BALB/c mice (4 weeks old) were used for the experiment and were divided into three major groups of vanadium treated, matched controls, and animals exposed to vanadium for three months and thereafter vanadium was withdrawn. Animals were tested using Morris water maze and forelimb grip test at 3, 6, 9, and 12 months of age. The results showed that animals across the groups showed no difference in learning but had significant loss in memory abilities after 3 months of vanadium exposure and this trend continued in all vanadium-exposed groups relative to the controls. Animals exposed to vanadium for three months recovered significantly only 9 months after vanadium withdrawal. There was no significant difference in latency to fall in the forelimb grip test between vanadium-exposed groups and the controls in all age groups. In conclusion, we have shown that chronic administration of vanadium in mice leads to memory deficit which is reversible but only after a long period of vanadium withdrawal.

A Scalable Multicore Architecture With Heterogeneous Memory Structures for Dynamic Neuromorphic Asynchronous Processors (DYNAPs).

PubMed

Moradi, Saber; Qiao, Ning; Stefanini, Fabio; Indiveri, Giacomo

2018-02-01

Neuromorphic computing systems comprise networks of neurons that use asynchronous events for both computation and communication. This type of representation offers several advantages in terms of bandwidth and power consumption in neuromorphic electronic systems. However, managing the traffic of asynchronous events in large scale systems is a daunting task, both in terms of circuit complexity and memory requirements. Here, we present a novel routing methodology that employs both hierarchical and mesh routing strategies and combines heterogeneous memory structures for minimizing both memory requirements and latency, while maximizing programming flexibility to support a wide range of event-based neural network architectures, through parameter configuration. We validated the proposed scheme in a prototype multicore neuromorphic processor chip that employs hybrid analog/digital circuits for emulating synapse and neuron dynamics together with asynchronous digital circuits for managing the address-event traffic. We present a theoretical analysis of the proposed connectivity scheme, describe the methods and circuits used to implement such scheme, and characterize the prototype chip. Finally, we demonstrate the use of the neuromorphic processor with a convolutional neural network for the real-time classification of visual symbols being flashed to a dynamic vision sensor (DVS) at high speed.

Parecoxib mitigates spatial memory impairment induced by sevoflurane anesthesia in aged rats.

PubMed

Gong, M; Chen, G; Zhang, X M; Xu, L H; Wang, H M; Yan, M

2012-05-01

Inflammation in brain plays a critical role in the pathogenesis of cognitive impairment. Anti-inflammatory therapy may thus constitute a novel approach for associated cognitive dysfunction. The present study investigated the effects of parecoxib in the prevention of cognitive impairments induced by sevoflurane in aged rats. Sixty-six aged rats were divided randomly into three groups: control group (n = 22, sham anesthesia), sevoflurane group (n = 22, received 2% sevoflurane for 5 h) and parecoxib group (n = 22, received intraperitoneal injections of 10 mg/kg parecoxib and then exposed to 2% sevoflurane for 5 h). Spatial learning performance was tested by Morris water maze. The expression of cyclooxygenase-2 protein and ultrastructure of synapse in hippocampus were measured. Sevoflurane anesthesia impaired the spatial learning and memory in aged rats. Compared with sevoflurane group, parecoxib group showed shorter escape latency and more number of crossings over the previous platform area. Furthermore, parecoxib treatment also significantly prevented the synaptic changes induced by sevoflurane. Parecoxib mitigates spatial memory impairment induced by sevoflurane anesthesia in aged rats. The synaptic morphometry change may be one of the mechanisms involved in learning and memory deficit. © 2012 The Authors. Acta Anaesthesiologica Scandinavica © 2012 The Acta Anaesthesiologica Scandinavica Foundation.

Low-level neural auditory discrimination dysfunctions in specific language impairment-A review on mismatch negativity findings.

PubMed

Kujala, Teija; Leminen, Miika

2017-12-01

In specific language impairment (SLI), there is a delay in the child's oral language skills when compared with nonverbal cognitive abilities. The problems typically relate to phonological and morphological processing and word learning. This article reviews studies which have used mismatch negativity (MMN) in investigating low-level neural auditory dysfunctions in this disorder. With MMN, it is possible to tap the accuracy of neural sound discrimination and sensory memory functions. These studies have found smaller response amplitudes and longer latencies for speech and non-speech sound changes in children with SLI than in typically developing children, suggesting impaired and slow auditory discrimination in SLI. Furthermore, they suggest shortened sensory memory duration and vulnerability of the sensory memory to masking effects. Importantly, some studies reported associations between MMN parameters and language test measures. In addition, it was found that language intervention can influence the abnormal MMN in children with SLI, enhancing its amplitude. These results suggest that the MMN can shed light on the neural basis of various auditory and memory impairments in SLI, which are likely to influence speech perception. Copyright © 2017. Published by Elsevier Ltd.