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Sample records for gating memory related

  1. Study of the relative performance of silicon and germanium nanoparticles embedded gate oxide in metal-oxide-semiconductor memory devices

    NASA Astrophysics Data System (ADS)

    Chakraborty, G.; Sengupta, A.; Requejo, F. G.; Sarkar, C. K.

    2011-03-01

    In the present work, we have investigated a comparative performance of the silicon (Si) and germanium (Ge) nanoparticles embedded SiO2 floating gate MOS memory devices. In such devices for low applied fields, the tunneling current is dominated by the direct tunneling mechanism, whereas for higher electric fields, the Fowler-Nordheim tunneling mechanism dominates. As the device dimensions get smaller, problem arises in the conventional MOS memory devices due to the leakage through the thin tunnel oxide. This leakage can be reduced via charge trapping by embedding nanoparticles in the gate dielectric of such devices. Here one objective is to prevent the leakage due to the direct tunneling mechanism and the other objective is to reduce the write voltage, by lowering the onset voltage of the Fowler-Nordheim tunneling mechanism. Our simulations for the current voltage characteristics covered both the low and the high applied field regions. Simulations showed that both the Si and the Ge nanoparticles embedded gate dielectrics offer reduction of the leakage current and a significant lowering of the writing or programming onset voltage, compared to the pure SiO2 gate dielectric. In terms of the comparative performance, the Germanium nanoparticles embedded gate dielectric showed better results compared to the silicon nanoparticles embedded one. The results of the simulations are discussed in the light of recent experimental results.

  2. MEMORIAL WALK WITH MEMORIALS, TOWARD ENTRANCE GATE. VIEW TO WEST. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    MEMORIAL WALK WITH MEMORIALS, TOWARD ENTRANCE GATE. VIEW TO WEST. - Rock Island National Cemetery, Rock Island Arsenal, 0.25 mile north of southern tip of Rock Island, Rock Island, Rock Island County, IL

  3. Radiation Issues and Applications of Floating Gate Memories

    NASA Technical Reports Server (NTRS)

    Scheick, L. Z.; Nguyen, D. N.

    2000-01-01

    The radiation effects that affect various systems that comprise floating gate memories are presented. The wear-out degradation results of unirradiated flash memories are compared to irradiated flash memories. The procedure analyzes the failure to write and erase caused by wear-out and degradation of internal charge pump circuits. A method is described for characterizing the radiation effects of the floating gate itself. The rate dependence, stopping power dependence, SEU susceptibility and applications of floating gate in radiation environment are presented. The ramifications for dosimetry and cell failure are discussed as well as for the long term use aspects of non-volatile memories.

  4. Stacked-Gate FET's For Analog Memory Elements

    NASA Technical Reports Server (NTRS)

    Thakoor, Anilkumar P.; Moopenn, Alexander W.

    1991-01-01

    Three-terminal, double-stacked-gate field-effect transistor (FET), developed as analog memory element. Particularly suited for use as synapse with variable connection strength in electronic neural network. Provides programmable, nonvolatile resistive connection, somewhat in manner of porous-gate FET described in "Porous-Floating-Gate Field-Effect Transistor" (NPO-17532). Resembles commercial erasable programmable read-only memory (EPROM) device, except for thickness of layers of silicon dioxide electrically isolating gates. Either p-channel or n-channel device.

  5. Corticostriatal output gating during selection from working memory.

    PubMed

    Chatham, Christopher H; Frank, Michael J; Badre, David

    2014-02-19

    Convergent evidence suggests that corticostriatal interactions act as a gate to select the input to working memory (WM). However, not all information in WM is relevant for behavior simultaneously. For this reason, a second "output gate" might advantageously govern which contents of WM influence behavior. Here, we test whether frontostriatal circuits previously implicated in input gating also support output gating during selection from WM. fMRI of a hierarchical rule task with dissociable input and output gating demands demonstrated greater lateral prefrontal cortex (PFC) recruitment and frontostriatal connectivity during output gating. Moreover, PFC and striatum correlated with distinct behavioral profiles. Whereas PFC recruitment correlated with mean efficiency of selection from WM, striatal recruitment and frontostriatal interactions correlated with its reliability, as though such dynamics stochastically gate WM's output. These results support the output gating hypothesis, suggesting that contextual representations in PFC influence striatum to select which information in WM drives responding.

  6. GATE AND FLANKING FENCE AT ENTRANCE TO MEMORIAL WALK. VIEW ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    GATE AND FLANKING FENCE AT ENTRANCE TO MEMORIAL WALK. VIEW TO NORTHEAST. - Rock Island National Cemetery, Rock Island Arsenal, 0.25 mile north of southern tip of Rock Island, Rock Island, Rock Island County, IL

  7. GETTYSBURG ADDRESS TABLET BESIDE ENTRANCE GATE AT MEMORIAL WALK. VIEW ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    GETTYSBURG ADDRESS TABLET BESIDE ENTRANCE GATE AT MEMORIAL WALK. VIEW TO EAST. - Rock Island National Cemetery, Rock Island Arsenal, 0.25 mile north of southern tip of Rock Island, Rock Island, Rock Island County, IL

  8. DETAIL OF FENCE FLANKING GATE AT ENTRANCE TO MEMORIAL WALK. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    DETAIL OF FENCE FLANKING GATE AT ENTRANCE TO MEMORIAL WALK. VIEW TO NORTHEAST. - Rock Island National Cemetery, Rock Island Arsenal, 0.25 mile north of southern tip of Rock Island, Rock Island, Rock Island County, IL

  9. Improved Reading Gate For Vertical-Bloch-Line Memory

    NASA Technical Reports Server (NTRS)

    Wu, Jiin-Chuan; Stadler, Henry L.; Katti, Romney R.

    1994-01-01

    Improved design for reading gate of vertical-Bloch-line magnetic-bubble memory increases reliability of discrimination between binary ones and zeros. Magnetic bubbles that signify binary "1" and "0" produced by applying sufficiently large chopping currents to memory stripes. Bubbles then propagated differentially in bubble sorter. Method of discriminating between ones and zeros more reliable.

  10. Floating Gate Memory with Biomineralized Nanodots Embedded in High-k Gate Dielectric

    NASA Astrophysics Data System (ADS)

    Ohara, Kosuke; Yamashita, Ichiro; Yaegashi, Toshitake; Moniwa, Masahiro; Yoshimaru, Masaki; Uraoka, Yukiharu

    2009-09-01

    The memory properties of a nanodot-type floating gate memory with Co bio-nanodots (Co-BNDs) embedded in HfO2 were investigated. High-density and uniform Co-BNDs were adsorbed on the HfO2 tunnel oxide using ferritin. The fabricated metal oxide semiconductor (MOS) capacitor exhibited a capacitance-voltage (C-V) curve with large hysteresis. The memory window size was 30 times higher than that of the MOS capacitor with a SiO2 gate oxide. Not only a large memory window but also excellent charge retention and reliability characteristics were obtained for a MOS field-effect transistor (MOSFET). This research confirmed that the proposed memory is promising for use in next-generation memory devices.

  11. Graphene-graphene oxide floating gate transistor memory.

    PubMed

    Jang, Sukjae; Hwang, Euyheon; Lee, Jung Heon; Park, Ho Seok; Cho, Jeong Ho

    2015-01-21

    A novel transparent, flexible, graphene channel floating-gate transistor memory (FGTM) device is fabricated using a graphene oxide (GO) charge trapping layer on a plastic substrate. The GO layer, which bears ammonium groups (NH3+), is prepared at the interface between the crosslinked PVP (cPVP) tunneling dielectric and the Al2 O3 blocking dielectric layers. Important design rules are proposed for a high-performance graphene memory device: (i) precise doping of the graphene channel, and (ii) chemical functionalization of the GO charge trapping layer. How to control memory characteristics by graphene doping is systematically explained, and the optimal conditions for the best performance of the memory devices are found. Note that precise control over the doping of the graphene channel maximizes the conductance difference at a zero gate voltage, which reduces the device power consumption. The proposed optimization via graphene doping can be applied to any graphene channel transistor-type memory device. Additionally, the positively charged GO (GO-NH3+) interacts electrostatically with hydroxyl groups of both UV-treated Al2 O3 and PVP layers, which enhances the interfacial adhesion, and thus the mechanical stability of the device during bending. The resulting graphene-graphene oxide FGTMs exhibit excellent memory characteristics, including a large memory window (11.7 V), fast switching speed (1 μs), cyclic endurance (200 cycles), stable retention (10(5) s), and good mechanical stability (1000 cycles).

  12. Solution processed molecular floating gate for flexible flash memories

    PubMed Central

    Zhou, Ye; Han, Su-Ting; Yan, Yan; Huang, Long-Biao; Zhou, Li; Huang, Jing; Roy, V. A. L.

    2013-01-01

    Solution processed fullerene (C60) molecular floating gate layer has been employed in low voltage nonvolatile memory device on flexible substrates. We systematically studied the charge trapping mechanism of the fullerene floating gate for both p-type pentacene and n-type copper hexadecafluorophthalocyanine (F16CuPc) semiconductor in a transistor based flash memory architecture. The devices based on pentacene as semiconductor exhibited both hole and electron trapping ability, whereas devices with F16CuPc trapped electrons alone due to abundant electron density. All the devices exhibited large memory window, long charge retention time, good endurance property and excellent flexibility. The obtained results have great potential for application in large area flexible electronic devices. PMID:24172758

  13. Learning to use working memory: a reinforcement learning gating model of rule acquisition in rats

    PubMed Central

    Lloyd, Kevin; Becker, Nadine; Jones, Matthew W.; Bogacz, Rafal

    2012-01-01

    Learning to form appropriate, task-relevant working memory representations is a complex process central to cognition. Gating models frame working memory as a collection of past observations and use reinforcement learning (RL) to solve the problem of when to update these observations. Investigation of how gating models relate to brain and behavior remains, however, at an early stage. The current study sought to explore the ability of simple RL gating models to replicate rule learning behavior in rats. Rats were trained in a maze-based spatial learning task that required animals to make trial-by-trial choices contingent upon their previous experience. Using an abstract version of this task, we tested the ability of two gating algorithms, one based on the Actor-Critic and the other on the State-Action-Reward-State-Action (SARSA) algorithm, to generate behavior consistent with the rats'. Both models produced rule-acquisition behavior consistent with the experimental data, though only the SARSA gating model mirrored faster learning following rule reversal. We also found that both gating models learned multiple strategies in solving the initial task, a property which highlights the multi-agent nature of such models and which is of importance in considering the neural basis of individual differences in behavior. PMID:23115551

  14. DIFMOS - A floating-gate electrically erasable nonvolatile semiconductor memory technology. [Dual Injector Floating-gate MOS

    NASA Technical Reports Server (NTRS)

    Gosney, W. M.

    1977-01-01

    Electrically alterable read-only memories (EAROM's) or reprogrammable read-only memories (RPROM's) can be fabricated using a single-level metal-gate p-channel MOS technology with all conventional processing steps. Given the acronym DIFMOS for dual-injector floating-gate MOS, this technology utilizes the floating-gate technique for nonvolatile storage of data. Avalanche injection of hot electrons through gate oxide from a special injector diode in each bit is used to charge the floating gates. A second injector structure included in each bit permits discharge of the floating gate by avalanche injection of holes through gate oxide. The overall design of the DIFMOS bit is dictated by the physical considerations required for each of the avalanche injector types. The end result is a circuit technology which can provide fully decoded bit-erasable EAROM-type circuits using conventional manufacturing techniques.

  15. Adult forebrain NMDA receptors gate social motivation and social memory.

    PubMed

    Jacobs, Stephanie; Tsien, Joe Z

    2017-02-01

    Motivation to engage in social interaction is critical to ensure normal social behaviors, whereas dysregulation in social motivation can contribute to psychiatric diseases such as schizophrenia, autism, social anxiety disorders and post-traumatic stress disorder (PTSD). While dopamine is well known to regulate motivation, its downstream targets are poorly understood. Given the fact that the dopamine 1 (D1) receptors are often physically coupled with the NMDA receptors, we hypothesize that the NMDA receptor activity in the adult forebrain principal neurons are crucial not only for learning and memory, but also for the proper gating of social motivation. Here, we tested this hypothesis by examining sociability and social memory in inducible forebrain-specific NR1 knockout mice. These mice are ideal for exploring the role of the NR1 subunit in social behavior because the NR1 subunit can be selectively knocked out after the critical developmental period, in which NR1 is required for normal development. We found that the inducible deletion of the NMDA receptors prior to behavioral assays impaired, not only object and social recognition memory tests, but also resulted in profound deficits in social motivation. Mice with ablated NR1 subunits in the forebrain demonstrated significant decreases in sociability compared to their wild type counterparts. These results suggest that in addition to its crucial role in learning and memory, the NMDA receptors in the adult forebrain principal neurons gate social motivation, independent of neuronal development.

  16. Auto and hetero-associative memory using a 2-D optical logic gate

    NASA Technical Reports Server (NTRS)

    Chao, Tien-Hsin (Inventor)

    1992-01-01

    An optical system for auto-associative and hetero-associative recall utilizing Hamming distance as the similarity measure between a binary input image vector V(sup k) and a binary image vector V(sup m) in a first memory array using an optical Exclusive-OR gate for multiplication of each of a plurality of different binary image vectors in memory by the input image vector. After integrating the light of each product V(sup k) x V(sup m), a shortest Hamming distance detection electronics module determines which product has the lowest light intensity and emits a signal that activates a light emitting diode to illuminate a corresponding image vector in a second memory array for display. That corresponding image vector is identical to the memory image vector V(sup m) in the first memory array for auto-associative recall or related to it, such as by name, for hetero-associative recall.

  17. Single-ion dosemeter based on floating gate memories.

    PubMed

    Cellere, G; Paccagnella, A; Visconti, A; Bonanomi, M; McNulty, P J

    2006-01-01

    Floating Gate (FG) nonvolatile memories are based on a tiny polysilicon layer (the FG) which can be permanently charged with electrons or holes, thus changing the threshold voltage of a MOSFET. Every time a FG is hit by a high energy ion, it experiences a charge loss, depending on the ion linear energy transfer (LET) and on the transistor geometrical and electrical characteristics. This paper discusses the opportunities to use this devices as single an ion dosemeter with sub-micrometer spatial resolution and capable of distinguish the impinging ion LET.

  18. Memory effect in silicon time-gated single-photon avalanche diodes

    SciTech Connect

    Dalla Mora, A.; Contini, D. Di Sieno, L.; Tosi, A.; Boso, G.; Villa, F.; Pifferi, A.

    2015-03-21

    We present a comprehensive characterization of the memory effect arising in thin-junction silicon Single-Photon Avalanche Diodes (SPADs) when exposed to strong illumination. This partially unknown afterpulsing-like noise represents the main limiting factor when time-gated acquisitions are exploited to increase the measurement dynamic range of very fast (picosecond scale) and faint (single-photon) optical signals following a strong stray one. We report the dependences of this unwelcome signal-related noise on photon wavelength, detector temperature, and biasing conditions. Our results suggest that this so-called “memory effect” is generated in the deep regions of the detector, well below the depleted region, and its contribution on detector response is visible only when time-gated SPADs are exploited to reject a strong burst of photons.

  19. Memory operations in Au nanoparticle single-electron transistors with floating gate electrodes

    NASA Astrophysics Data System (ADS)

    Azuma, Yasuo; Sakamoto, Masanori; Teranishi, Toshiharu; Majima, Yutaka

    2016-11-01

    Floating gate memory operations are demonstrated in a single-electron transistor (SET) fabricated by a chemical assembly using the Au nanogap electrodes and the chemisorbed Au nanoparticles. By applying pulse voltages to the control gate, phase shifts were clearly and stably observed both in the Coulomb oscillations and in the Coulomb diamonds. Writing and erasing operations on the floating gate memory were reproducibly observed, and the charges on the floating gate electrodes were maintained for at least 12 h. By considering the capacitance of the floating gate electrode, the number of electrons in the floating gate electrode was estimated as 260. Owing to the stability of the fabricated SET, these writing and erasing operations on the floating gate memory can be applied to reconfigurable SET circuits fabricated by a chemically assembled technique.

  20. Extraction of the gate capacitance coupling coefficient in floating gate non-volatile memories: Statistical study of the effect of mismatching between floating gate memory and reference transistor in dummy cell extraction methods

    NASA Astrophysics Data System (ADS)

    Rafhay, Quentin; Beug, M. Florian; Duane, Russell

    2007-04-01

    This paper presents an experimental comparison of dummy cell extraction methods of the gate capacitance coupling coefficient for floating gate non-volatile memory structures from different geometries and technologies. These results show the significant influence of mismatching floating gate devices and reference transistors on the extraction of the gate capacitance coupling coefficient. In addition, it demonstrates the accuracy of the new bulk bias dummy cell extraction method and the importance of the β function, introduced recently in [Duane R, Beug F, Mathewson A. Novel capacitance coupling coefficient measurement methodology for floating gate non-volatile memory devices. IEEE Electr Dev Lett 2005;26(7):507-9], to determine matching pairs of floating gate memory and reference transistor.

  1. Floating-Gate Type Organic Memory with Organic Insulator Thin Film of Plasma Polymerized Methyl Methacrylate

    NASA Astrophysics Data System (ADS)

    Kim, Hee-sung; Lee, Boong-Joo; Kim, Gun-Su; Shin, Paik-Kyun

    2013-02-01

    To fabricate organic memory device by entirely dry process, plasma polymerized methyl methacrylate (ppMMA) thin films were prepared and they were used as both tunneling layer and gate insulator layer in a floating-gate type organic memory device. The ppMMA thin films were prepared with inductively coupled plasma (ICP) source combined with stabilized monomer vapor control. The ppMMA gate insulator thin film revealed dielectric constant of 3.75 and low leakage current of smaller than 10-9 A/cm. The floating-gate type organic memory device showed promising memory characteristics such as memory window value of 12 V and retention time of over 2 h, where 60 V of writing voltage and -30 V of erasing voltage were applied, respectively.

  2. Organic field-effect transistor nonvolatile memories utilizing sputtered C nanoparticles as nano-floating-gate

    SciTech Connect

    Liu, Jie; Liu, Chang-Hai; She, Xiao-Jian; Sun, Qi-Jun; Gao, Xu; Wang, Sui-Dong

    2014-10-20

    High-performance organic field-effect transistor nonvolatile memories have been achieved using sputtered C nanoparticles as the nano-floating-gate. The sputtered C nano-floating-gate is prepared with low-cost material and simple process, forming uniform and discrete charge trapping sites covered by a smooth and complete polystyrene layer. The devices show large memory window, excellent retention capability, and programming/reading/erasing/reading endurance. The sputtered C nano-floating-gate can effectively trap both holes and electrons, and it is demonstrated to be suitable for not only p-type but also n-type organic field-effect transistor nonvolatile memories.

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

    NASA Astrophysics Data System (ADS)

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

    2013-10-01

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

  4. Nonvolatile ``AND,'' ``OR,'' and ``NOT'' Boolean logic gates based on phase-change memory

    NASA Astrophysics Data System (ADS)

    Li, Y.; Zhong, Y. P.; Deng, Y. F.; Zhou, Y. X.; Xu, L.; Miao, X. S.

    2013-12-01

    Electronic devices or circuits that can implement both logic and memory functions are regarded as the building blocks for future massive parallel computing beyond von Neumann architecture. Here we proposed phase-change memory (PCM)-based nonvolatile logic gates capable of AND, OR, and NOT Boolean logic operations verified in SPICE simulations and circuit experiments. The logic operations are parallel computing and results can be stored directly in the states of the logic gates, facilitating the combination of computing and memory in the same circuit. These results are encouraging for ultralow-power and high-speed nonvolatile logic circuit design based on novel memory devices.

  5. Effect of tunneling layers on the performances of floating-gate based organic thin-film transistor nonvolatile memories

    SciTech Connect

    Wang, Wei Han, Jinhua; Ying, Jun; Xiang, Lanyi; Xie, Wenfa

    2014-09-22

    Two types of floating-gate based organic thin-film transistor nonvolatile memories (FG-OTFT-NVMs) were demonstrated, with poly(methyl methacrylate co glycidyl methacrylate) (P(MMA-GMA)) and tetratetracontane (TTC) as the tunneling layer, respectively. Their device performances were measured and compared. In the memory with a P(MMA-GMA) tunneling layer, typical unipolar hole transport was obtained with a relatively small mobility of 0.16 cm{sup 2}/V s. The unidirectional shift of turn-on voltage (V{sub on}) due to only holes trapped/detrapped in/from the floating gate resulted in a small memory window of 12.5 V at programming/erasing voltages (V{sub P}/V{sub E}) of ±100 V and a nonzero reading voltage. Benefited from the well-ordered molecule orientation and the trap-free surface of TTC layer, a considerably high hole mobility of 1.7 cm{sup 2}/V s and a visible feature of electrons accumulated in channel and trapped in floating-gate were achieved in the memory with a TTC tunneling layer. High hole mobility resulted in a high on current and a large memory on/off ratio of 600 at the V{sub P}/V{sub E} of ±100 V. Both holes and electrons were injected into floating-gate and overwritten each other, which resulted in a bidirectional V{sub on} shift. As a result, an enlarged memory window of 28.6 V at the V{sub P}/V{sub E} of ±100 V and a zero reading voltage were achieved. Based on our results, a strategy is proposed to optimize FG-OTFT-NVMs by choosing a right tunneling layer to improve the majority carrier mobility and realize ambipolar carriers injecting and trapping in the floating-gate.

  6. Effects of abnormal cell-to-cell interference on p-type floating gate and control gate NAND flash memory

    NASA Astrophysics Data System (ADS)

    Kim, Yong Jun; Kang, Jun Geun; Lee, Byungin; Cho, Gyu-Seog; Park, Sung-Kye; Choi, Woo Young

    2014-01-01

    Abnormal cell-to-cell interference occurring in NAND flash memory has been investigated. In the case of extremely downscaled NAND flash memory, cell-to-cell interference increases abnormally. The abnormal cell-to-cell interference has been observed in a p-type floating gate (FG)/control gate (CG) cells for the first time. It has been found that the depletion region variation leads to the abnormal cell-to-cell interference. The depletion region variation of FG and CG is determined by state of neighbor cells. The depletion region variation affects CG-to-FG coupling capacitance and threshold voltage variation (ΔVT). Finally, it is observed that there is a symmetrical relationship between n- and p-type FG/CG NAND flash memory in terms of cell-to-cell interference.

  7. Ambipolar nonvolatile memory based on a quantum-dot transistor with a nanoscale floating gate

    NASA Astrophysics Data System (ADS)

    Che, Yongli; Zhang, Yating; Cao, Xiaolong; Song, Xiaoxian; Cao, Mingxuan; Dai, Haitao; Yang, Junbo; Zhang, Guizhong; Yao, Jianquan

    2016-07-01

    Using only solution processing methods, we developed ambipolar quantum-dot (QD) transistor floating-gate memory (FGM) that uses Au nanoparticles as a floating gate. Because of the bipolarity of the active channel of PbSe QDs, the memory could easily trap holes or electrons in the floating gate by programming/erasing (P/E) operations, which could shift the threshold voltage both up and down. As a result, the memory exhibited good programmable memory characteristics: a large memory window (ΔVth ˜ 15 V) and a long retention time (>105 s). The magnitude of ΔVth depended on both P/E voltages and the bias voltage (VDS): ΔVth was a cubic function to VP/E and linearly depended on VDS. Therefore, this FGM based on a QD transistor is a promising alternative to its inorganic counterparts owing to its advantages of bipolarity, high mobility, low cost, and large-area production.

  8. Quantum Dot Channel (QDC) Field Effect Transistors (FETs) and Floating Gate Nonvolatile Memory Cells

    NASA Astrophysics Data System (ADS)

    Kondo, J.; Lingalugari, M.; Chan, P.-Y.; Heller, E.; Jain, F.

    2015-09-01

    This paper presents silicon quantum dot channel (QDC) field effect transistors (FETs) and floating gate nonvolatile memory structures. The QDC-FET operation is explained by carrier transport in narrow mini-energy bands which are manifested in an array of SiO x -cladded silicon quantum dot layers. For nonvolatile memory structures, simulations of electron charge densities in the floating quantum dot layers are presented. Experimental threshold voltage shift in I D- V G characteristics is presented after the `Write' cycle. The QDC-FETs and nonvolatile memory due to improved threshold voltage variations by incorporating the lattice-matched II-VI layer as the gate insulator.

  9. Molecular floating-gate organic nonvolatile memory with a fully solution processed core architecture

    NASA Astrophysics Data System (ADS)

    Wu, Chao; Wang, Wei; Song, Junfeng

    2016-11-01

    In this paper, we demonstrated a floating-gate organic thin film transistor based nonvolatile memory, in which the core architecture was processed by a sequential three-step solution spin-coating method. The molecular semiconductor 6,13-bis(triisopropylsilylethynyl)pentacene (TIPS-Pen) distributing in the matrix of polymer poly(styrene) (PS), acting as the floating-gate and tunneling layer, respectively, was processed by one-step spin-coating from their blending solution. The effect of the proportion of TIPS-Pen in the matrix of PS on the memory performances of devices was researched. As a result, a good nonvolatile memory was achieved, with a memory window larger than 25 V, stable memory endurance property over 500 cycles and retention time longer than 5000 s with a high memory ratio larger than 102, at an optimal proportion of TIPS-Pen in the matrix of PS.

  10. Al2O3 nanocrystals embedded in amorphous Lu2O3 high-k gate dielectric for floating gate memory application

    NASA Astrophysics Data System (ADS)

    Yuan, C. L.; Chan, M. Y.; Lee, P. S.; Darmawan, P.; Setiawan, Y.

    2007-04-01

    The integration of nanoparticles has high potential in technological applications and opens up possibilities of the development of new devices. Compared to the conventional floating gate memory, a structure containing nanocrystals embedded in dielectrics shows high potential to produce a memory with high endurance, low operating voltage, fast write-erase speeds and better immunity to soft errors [S. Tiwari, F. Rana, H. Hanafi et al. 1996 Appl.Phys. Lett. 68, 1377]. A significant improvement on data retention [J. J. Lee, X. Wang et al. 2003 Proceedings of the VLSI Technol. Symposium, p33] can be observed when discrete nanodots are used instead of continuous floating gate as charge storage nodes because local defect related leakage can be reduced efficiently. Furthermore, using a high-k dielectric in place of the conventional SiO2 based dielectric, nanodots flash memory is able to achieve significantly improved programming efficiency and data retention [A. Thean and J. -P. Leburton, 2002 IEEE Potentials 21, 35; D. W. Kim, T. Kim and S. K. Banerjee, 2003 IEEE Trans. Electron Devices 50, 1823]. We have recently successfully developed a method to produce nanodots embedded in high-k gate dielectrics [C. L. Yuan, P. Darmawan, Y. Setiawan and P. S. Lee, 2006 Electrochemical and Solid-State Letters 9, F53; C. L. Yuan, P. Darmawan, Y. Setiawan and P. S. Lee, 2006 Europhys. Lett. 74, 177]. In this paper, we fabricated the memory structure of Al2O3 nanocrystals embedded in amorphous Lu2O3 high k dielectric using pulsed laser ablation. The mean size and density of the Al2O3 nanocrystals are estimated to be about 5 nm and 7x1011 cm-2, respectively. Good electrical performances in terms of large memory window and good data retention were observed. Our preparation method is simple, fast and economical.

  11. Hybrid Flexible Resistive Random Access Memory-Gated Transistor for Novel Nonvolatile Data Storage.

    PubMed

    Han, Su-Ting; Zhou, Ye; Chen, Bo; Wang, Chundong; Zhou, Li; Yan, Yan; Zhuang, Jiaqing; Sun, Qijun; Zhang, Hua; Roy, V A L

    2016-01-20

    Here, a single-device demonstration of novel hybrid architecture is reported to achieve programmable transistor nodes which have analogies to flash memory by incorporating a resistive switching random access memory (RRAM) device as a resistive switch gate for field effect transistor (FET) on a flexible substrate. A high performance flexible RRAM with a three-layered structure is fabricated by utilizing solution-processed MoS2 nanosheets sandwiched between poly(methyl methacrylate) polymer layers. Gate coupling with the pentacene-based transistor can be controlled by the RRAM memory state to produce a nonprogrammed state (inactive) and a programmed state (active) with a well-defined memory window. Compared to the reference flash memory device based on the MoS2 floating gate, the hybrid device presents robust access speed and retention ability. Furthermore, the hybrid RRAM-gated FET is used to build an integrated logic circuit and a wide logic window in inverter logic is achieved. The controllable, well-defined memory window, long retention time, and fast access speed of this novel hybrid device may open up new possibilities of realizing fully functional nonvolatile memory for high-performance flexible electronics.

  12. Nonvolatile Transistor Memory with Self-Assembled Semiconducting Polymer Nanodomain Floating Gates.

    PubMed

    Wang, Wei; Kim, Kang Lib; Cho, Suk Man; Lee, Ju Han; Park, Cheolmin

    2016-12-14

    Organic field effect transistor based nonvolatile memory (OFET-NVM) with semiconducting nanofloating gates offers additional benefits over OFET-NVMs with conventional metallic floating gates due to the facile controllability of charge storage based on the energetic structure of the floating gate. In particular, an all-in-one tunneling and floating-gate layer in which the semiconducting polymer nanodomains are self-assembled in the dielectric tunneling layer is promising. In this study, we utilize crystals of a p-type semiconducting polymer in which the crystalline lamellae of the polymer are spontaneously developed and embedded in the tunneling matrix as the nanofloating gate. The widths and lengths of the polymer nanodomains are approximately 20 nm and a few hundred nanometers, respectively. An OFET-NVM containing the crystalline nanofloating gates exhibits memory performance with a large memory window of 10 V, programming/erasing switching endurance for over 500 cycles, and a long retention time of 5000 s. Moreover, the device performance is improved by comixing with an n-type semiconductor; thus, the solution-processed p- and n-type double floating gates capable of storing both holes and electrons allow for the multilevel operation of our OFET-NVM. Four highly reliable levels (two bits per cell) of charge trapping and detrapping are achieved using this OFET-NVM by accurately choosing the programming/erasing voltages.

  13. The Role of Anterior Nuclei of the Thalamus: A Subcortical Gate in Memory Processing: An Intracerebral Recording Study

    PubMed Central

    Štillová, Klára; Jurák, Pavel; Chládek, Jan; Chrastina, Jan; Halámek, Josef; Bočková, Martina; Goldemundová, Sabina; Říha, Ivo; Rektor, Ivan

    2015-01-01

    Objective To study the involvement of the anterior nuclei of the thalamus (ANT) as compared to the involvement of the hippocampus in the processes of encoding and recognition during visual and verbal memory tasks. Methods We studied intracerebral recordings in patients with pharmacoresistent epilepsy who underwent deep brain stimulation (DBS) of the ANT with depth electrodes implanted bilaterally in the ANT and compared the results with epilepsy surgery candidates with depth electrodes implanted bilaterally in the hippocampus. We recorded the event-related potentials (ERPs) elicited by the visual and verbal memory encoding and recognition tasks. Results P300-like potentials were recorded in the hippocampus by visual and verbal memory encoding and recognition tasks and in the ANT by the visual encoding and visual and verbal recognition tasks. No significant ERPs were recorded during the verbal encoding task in the ANT. In the visual and verbal recognition tasks, the P300-like potentials in the ANT preceded the P300-like potentials in the hippocampus. Conclusions The ANT is a structure in the memory pathway that processes memory information before the hippocampus. We suggest that the ANT has a specific role in memory processes, especially memory recognition, and that memory disturbance should be considered in patients with ANT-DBS and in patients with ANT lesions. ANT is well positioned to serve as a subcortical gate for memory processing in cortical structures. PMID:26529407

  14. Direct probing of electron and hole trapping into nano-floating-gate in organic field-effect transistor nonvolatile memories

    SciTech Connect

    Cui, Ze-Qun; Wang, Shun; Chen, Jian-Mei; Gao, Xu; Dong, Bin E-mail: chilf@suda.edu.cn Chi, Li-Feng E-mail: chilf@suda.edu.cn Wang, Sui-Dong E-mail: chilf@suda.edu.cn

    2015-03-23

    Electron and hole trapping into the nano-floating-gate of a pentacene-based organic field-effect transistor nonvolatile memory is directly probed by Kelvin probe force microscopy. The probing is straightforward and non-destructive. The measured surface potential change can quantitatively profile the charge trapping, and the surface characterization results are in good accord with the corresponding device behavior. Both electrons and holes can be trapped into the nano-floating-gate, with a preference of electron trapping than hole trapping. The trapped charge quantity has an approximately linear relation with the programming/erasing gate bias, indicating that the charge trapping in the device is a field-controlled process.

  15. Auto- and hetero-associative memory using a 2-D optical logic gate

    NASA Technical Reports Server (NTRS)

    Chao, Tien-Hsin

    1989-01-01

    An optical associative memory system suitable for both auto- and hetero-associative recall is demonstrated. This system utilizes Hamming distance as the similarity measure between a binary input and a memory image with the aid of a two-dimensional optical EXCLUSIVE OR (XOR) gate and a parallel electronics comparator module. Based on the Hamming distance measurement, this optical associative memory performs a nearest neighbor search and the result is displayed in the output plane in real-time. This optical associative memory is fast and noniterative and produces no output spurious states as compared with that of the Hopfield neural network model.

  16. Gate Oxide Reliability Characterization of Tungsten Polymetal Gate with Low-Contact-Resistive WSix/WN Diffusion Barrier in Memory Devices

    NASA Astrophysics Data System (ADS)

    Sung, Min Gyu; Lim, Kwan-Yong; Cho, Heung-Jae; Lee, Seung Ryong; Jang, Se-Aug; Kim, Yong Soo; Kim, Tae-Yoon; Yang, Hong-Seon; Ku, Ja-Chun; Kim, Jin Woong

    2007-11-01

    Gate oxide reliability characteristics using different diffusion barrier metals for a tungsten polycrystalline silicon (poly-Si) gate stack were investigated in detail. The insertion of a thin WSix layer in a tungsten poly gate stack could effectively relieve the mechanical stress of a gate hardmask nitride film during a post thermal process, which contributes to better gate oxide reliability and the stress-immunity of the transistor. This insertion could also prevent the formation of a Si-N inter-dielectric layer, which could lower the contact resistance between poly and tungsten effectively. A W/WN/WSix/poly gate stack could be a promising candidate for a future W poly gate that shows reliable high-speed characteristics in dynamic random access memory applications.

  17. Evidence for a role of GABA- and glutamate-gated chloride channels in olfactory memory.

    PubMed

    Boumghar, Katia; Couret-Fauvel, Thomas; Garcia, Mikael; Armengaud, Catherine

    2012-11-01

    In the honeybee, we investigated the role of transmissions mediated by GABA-gated chloride channels and glutamate-gated chloride channels (GluCls) of the mushroom bodies (MBs) on olfactory learning using a single-trial olfactory conditioning paradigm. The GABAergic antagonist picrotoxin (PTX) or the GluCl antagonist L-trans-pyrrolidine-2,4-dicarboxylic acid (L-trans-PDC) was injected alone or in combination into the α-lobes of MBs. PTX impaired early long-term olfactory memory when injected before conditioning or before testing. L-trans-PDC alone induced no significant effect on learning and memory but induced a less specific response to the conditioned odor. When injected before PTX, L-trans-PDC was able to modulate PTX effects. These results emphasize the role of MB GABA-gated chloride channels in consolidation processes and strongly support that GluCls are involved in the perception of the conditioned stimulus.

  18. Hydrogen annealing of silicon gate-nitride-oxide-silicon nonvolatile memory devices

    NASA Astrophysics Data System (ADS)

    Topich, James A.; Turi, Raymond A.

    1982-10-01

    A hydrogen annealing study of silicon gate-nitride-oxide-silicon (SNOS) nonvolatile memory devices showed that the important parameter in determining the optimum hydrogen annealing temperature for maximum charge retention is the previous thermal history of the memory devices. If a memory device's charge retention is not degraded by high-temperature processing, then the hydrogen anneal should be at the silicon nitride deposition temperature. If a device is degraded by high-temperature processing, then the hydrogen anneal should be at the degradation temperature.

  19. Graphene-ferroelectric metadevices for nonvolatile memory and reconfigurable logic-gate operations.

    PubMed

    Kim, Woo Young; Kim, Hyeon-Don; Kim, Teun-Teun; Park, Hyun-Sung; Lee, Kanghee; Choi, Hyun Joo; Lee, Seung Hoon; Son, Jaehyeon; Park, Namkyoo; Min, Bumki

    2016-01-27

    Memory metamaterials are artificial media that sustain transformed electromagnetic properties without persistent external stimuli. Previous memory metamaterials were realized with phase-change materials, such as vanadium dioxide or chalcogenide glasses, which exhibit memory behaviour with respect to electrically/optically induced thermal stimuli. However, they require a thermally isolated environment for longer retention or strong optical pump for phase-change. Here we demonstrate electrically programmable nonvolatile memory metadevices realised by the hybridization of graphene, a ferroelectric and meta-atoms/meta-molecules, and extend the concept further to establish reconfigurable logic-gate metadevices. For a memory metadevice having a single electrical input, amplitude, phase and even the polarization multi-states were clearly distinguishable with a retention time of over 10 years at room temperature. Furthermore, logic-gate functionalities were demonstrated with reconfigurable logic-gate metadevices having two electrical inputs, with each connected to separate ferroelectric layers that act as the multi-level controller for the doping level of the sandwiched graphene layer.

  20. Graphene-ferroelectric metadevices for nonvolatile memory and reconfigurable logic-gate operations

    NASA Astrophysics Data System (ADS)

    Kim, Woo Young; Kim, Hyeon-Don; Kim, Teun-Teun; Park, Hyun-Sung; Lee, Kanghee; Choi, Hyun Joo; Lee, Seung Hoon; Son, Jaehyeon; Park, Namkyoo; Min, Bumki

    2016-01-01

    Memory metamaterials are artificial media that sustain transformed electromagnetic properties without persistent external stimuli. Previous memory metamaterials were realized with phase-change materials, such as vanadium dioxide or chalcogenide glasses, which exhibit memory behaviour with respect to electrically/optically induced thermal stimuli. However, they require a thermally isolated environment for longer retention or strong optical pump for phase-change. Here we demonstrate electrically programmable nonvolatile memory metadevices realised by the hybridization of graphene, a ferroelectric and meta-atoms/meta-molecules, and extend the concept further to establish reconfigurable logic-gate metadevices. For a memory metadevice having a single electrical input, amplitude, phase and even the polarization multi-states were clearly distinguishable with a retention time of over 10 years at room temperature. Furthermore, logic-gate functionalities were demonstrated with reconfigurable logic-gate metadevices having two electrical inputs, with each connected to separate ferroelectric layers that act as the multi-level controller for the doping level of the sandwiched graphene layer.

  1. Graphene–ferroelectric metadevices for nonvolatile memory and reconfigurable logic-gate operations

    PubMed Central

    Kim, Woo Young; Kim, Hyeon-Don; Kim, Teun-Teun; Park, Hyun-Sung; Lee, Kanghee; Choi, Hyun Joo; Lee, Seung Hoon; Son, Jaehyeon; Park, Namkyoo; Min, Bumki

    2016-01-01

    Memory metamaterials are artificial media that sustain transformed electromagnetic properties without persistent external stimuli. Previous memory metamaterials were realized with phase-change materials, such as vanadium dioxide or chalcogenide glasses, which exhibit memory behaviour with respect to electrically/optically induced thermal stimuli. However, they require a thermally isolated environment for longer retention or strong optical pump for phase-change. Here we demonstrate electrically programmable nonvolatile memory metadevices realised by the hybridization of graphene, a ferroelectric and meta-atoms/meta-molecules, and extend the concept further to establish reconfigurable logic-gate metadevices. For a memory metadevice having a single electrical input, amplitude, phase and even the polarization multi-states were clearly distinguishable with a retention time of over 10 years at room temperature. Furthermore, logic-gate functionalities were demonstrated with reconfigurable logic-gate metadevices having two electrical inputs, with each connected to separate ferroelectric layers that act as the multi-level controller for the doping level of the sandwiched graphene layer. PMID:26813710

  2. Organic Memory Transistors Using Monolayer of Semiconductor Colloidal Nano-Dots as a Floating Gate

    NASA Astrophysics Data System (ADS)

    Kajimoto, Kaori; Matsui, Daisuke; Uno, Kazuyuki; Tanaka, Ichiro

    2013-05-01

    We fabricated pentacene-based memory field-effect transistors (FETs) in which a monolayer of semiconductor colloidal nano-dots (NDs) is embedded as a floating gate. After a sufficiently large writing voltage was applied on the control gate, the fabricated FETs showed a large positive threshold voltage (Vth) shift that was attributed to electrons trapped in embedded NDs. The Vth shift was measured as a function of the writing voltage, and it was shown that the minimum writing voltage for memory FETs with small NDs is significantly larger than that for FETs with large ones. This result supports the proposed model of the memory effect in which electrons that tunneled from nearby pentacene molecules are trapped in embedded NDs because the electron energy level in small NDs is higher than that in large ones.

  3. The nature of working memory gating in Parkinson's disease: A multi-domain signal detection examination.

    PubMed

    Uitvlugt, Mitchell G; Pleskac, Timothy J; Ravizza, Susan M

    2016-04-01

    Distractions are ubiquitous; our brains are inundated with task-irrelevant information. Thus, to remember successfully, one must actively maintain relevant information and prevent distraction from entering working memory. Researchers suggest the basal ganglia-prefrontal pathways are vital to this process by acting as a working memory gate. Using Parkinson's disease as a model of frontostriatal functioning and with signal detection analyses, the present study aims to better characterize the contribution of frontostriatal pathways of this gating process and to determine how it operates across multiple domains. To achieve this, Parkinson's disease patients and healthy controls completed verbal and spatial working memory tasks consisting of three conditions: low-load without distraction; low-load with distraction; and high-load without distraction. Patients were tested both ON and OFF dopaminergic medication, allowing for assessment of the contribution of dorsal and ventral frontostriatal pathways. The results demonstrate that when medication is withheld, Parkinson's patients have a response bias to answer "NO" across all conditions and domains, supporting our hypothesis that the basal ganglia-prefrontal pathways allow or prevent updates of working memory. Contrastingly, medication status affects d' in the distraction condition but not in the high- or low-load conditions. We attribute this to stimulus valuation processes that were impaired by dopaminergic medication overdosing the ventral pathway. These findings are both consistent with the hypothesis that the working memory gate filters spatial and verbal information before it enters into the working memory system, adding support for the gate being a domain-general mechanism of the central executive.

  4. High-performance black phosphorus top-gate ferroelectric transistor for nonvolatile memory applications

    NASA Astrophysics Data System (ADS)

    Lee, Young Tack; Hwang, Do Kyung; Choi, Won Kook

    2016-10-01

    Two-dimensional (2D) van der Waals (vdW) atomic crystals have been extensively studied and significant progress has been made. The newest 2D vdW material, called black phosphorus (BP), has attracted considerable attention due to its unique physical properties, such as its being a singlecomponent material like graphene, and its having a high mobility and direct band gap. Here, we report on a high-performance BP nanosheet based ferroelectric field effect transistor (FeFET) with a poly(vinylidenefluoride-trifluoroethylene) top-gate insulator for a nonvolatile memory application. The BP FeFETs show the highest linear hole mobility of 563 cm2/Vs and a clear memory window of more than 15 V. For more advanced nonvolatile memory circuit applications, two different types of resistive-load and complementary ferroelectric memory inverters were implemented, which showed distinct memory on/off switching characteristics.

  5. Controlling Working Memory Operations by Selective Gating: The Roles of Oscillations and Synchrony

    PubMed Central

    Dipoppa, Mario; Szwed, Marcin; Gutkin, Boris S.

    2016-01-01

    Working memory (WM) is a primary cognitive function that corresponds to the ability to update, stably maintain, and manipulate short-term memory (ST M) rapidly to perform ongoing cognitive tasks. A prevalent neural substrate of WM coding is persistent neural activity, the property of neurons to remain active after having been activated by a transient sensory stimulus. This persistent activity allows for online maintenance of memory as well as its active manipulation necessary for task performance. WM is tightly capacity limited. Therefore, selective gating of sensory and internally generated information is crucial for WM function. While the exact neural substrate of selective gating remains unclear, increasing evidence suggests that it might be controlled by modulating ongoing oscillatory brain activity. Here, we review experiments and models that linked selective gating, persistent activity, and brain oscillations, putting them in the more general mechanistic context of WM. We do so by defining several operations necessary for successful WM function and then discussing how such operations may be carried out by mechanisms suggested by computational models. We specifically show how oscillatory mechanisms may provide a rapid and flexible active gating mechanism for WM operations. PMID:28154616

  6. Microdose Induced Data Loss on Floating Gate Memories

    NASA Technical Reports Server (NTRS)

    Guertin, Steven M.; Nguyen, Duc M.; Patterson, Jeffrey D.

    2006-01-01

    Heavy ion irradiation of flash memories shows loss of stored data. The fluence dependence is indicative of microdose effects. Other qualitative factors identifying the effect as microdose are discussed. The data is presented, and compared to statistical results of a microdose target-based model.

  7. High Performance Transparent Transistor Memory Devices Using Nano-Floating Gate of Polymer/ZnO Nanocomposites

    PubMed Central

    Shih, Chien-Chung; Lee, Wen-Ya; Chiu, Yu-Cheng; Hsu, Han-Wen; Chang, Hsuan-Chun; Liu, Cheng-Liang; Chen, Wen-Chang

    2016-01-01

    Nano-floating gate memory devices (NFGM) using metal nanoparticles (NPs) covered with an insulating polymer have been considered as a promising electronic device for the next-generation nonvolatile organic memory applications NPs. However, the transparency of the device with metal NPs is restricted to 60~70% due to the light absorption in the visible region caused by the surface plasmon resonance effects of metal NPs. To address this issue, we demonstrate a novel NFGM using the blends of hole-trapping poly (9-(4-vinylphenyl) carbazole) (PVPK) and electron-trapping ZnO NPs as the charge storage element. The memory devices exhibited a remarkably programmable memory window up to 60 V during the program/erase operations, which was attributed to the trapping/detrapping of charge carriers in ZnO NPs/PVPK composite. Furthermore, the devices showed the long-term retention time (>105 s) and WRER test (>200 cycles), indicating excellent electrical reliability and stability. Additionally, the fabricated transistor memory devices exhibited a relatively high transparency of 90% at the wavelength of 500 nm based on the spray-coated PEDOT:PSS as electrode, suggesting high potential for transparent organic electronic memory devices. PMID:26831222

  8. Gating of memory encoding of time-delayed cross-frequency MEG networks revealed by graph filtration based on persistent homology.

    PubMed

    Hahm, Jarang; Lee, Hyekyoung; Park, Hyojin; Kang, Eunjoo; Kim, Yu Kyeong; Chung, Chun Kee; Kang, Hyejin; Lee, Dong Soo

    2017-02-07

    To explain gating of memory encoding, magnetoencephalography (MEG) was analyzed over multi-regional network of negative correlations between alpha band power during cue (cue-alpha) and gamma band power during item presentation (item-gamma) in Remember (R) and No-remember (NR) condition. Persistent homology with graph filtration on alpha-gamma correlation disclosed topological invariants to explain memory gating. Instruction compliance (R-hits minus NR-hits) was significantly related to negative coupling between the left superior occipital (cue-alpha) and the left dorsolateral superior frontal gyri (item-gamma) on permutation test, where the coupling was stronger in R than NR. In good memory performers (R-hits minus false alarm), the coupling was stronger in R than NR between the right posterior cingulate (cue-alpha) and the left fusiform gyri (item-gamma). Gating of memory encoding was dictated by inter-regional negative alpha-gamma coupling. Our graph filtration over MEG network revealed these inter-regional time-delayed cross-frequency connectivity serve gating of memory encoding.

  9. Gating of memory encoding of time-delayed cross-frequency MEG networks revealed by graph filtration based on persistent homology

    PubMed Central

    Hahm, Jarang; Lee, Hyekyoung; Park, Hyojin; Kang, Eunjoo; Kim, Yu Kyeong; Chung, Chun Kee; Kang, Hyejin; Lee, Dong Soo

    2017-01-01

    To explain gating of memory encoding, magnetoencephalography (MEG) was analyzed over multi-regional network of negative correlations between alpha band power during cue (cue-alpha) and gamma band power during item presentation (item-gamma) in Remember (R) and No-remember (NR) condition. Persistent homology with graph filtration on alpha-gamma correlation disclosed topological invariants to explain memory gating. Instruction compliance (R-hits minus NR-hits) was significantly related to negative coupling between the left superior occipital (cue-alpha) and the left dorsolateral superior frontal gyri (item-gamma) on permutation test, where the coupling was stronger in R than NR. In good memory performers (R-hits minus false alarm), the coupling was stronger in R than NR between the right posterior cingulate (cue-alpha) and the left fusiform gyri (item-gamma). Gating of memory encoding was dictated by inter-regional negative alpha-gamma coupling. Our graph filtration over MEG network revealed these inter-regional time-delayed cross-frequency connectivity serve gating of memory encoding. PMID:28169281

  10. Silicon dioxide embedded germanium nanocrystals grown using molecular beam epitaxy for floating gate memory devices.

    PubMed

    Das, S; Singha, R K; Das, K; Dhar, A; Ray, S K

    2009-09-01

    SiO2/Ge nanocrystals/SiO2 trilayer memory structure has been fabricated by oxidizing and subsequent annealing of self assembled SiGe nanoislands grown by molecular beam epitaxy. The optical and charge storage characteristics of trilayer structures have been studied through Raman spectroscopy and capacitance-voltage measurements, respectively. An anti-clockwise hysteresis in the C-V characteristics indicated the net electron trapping in the floating gate containing Ge nanocrystals. Frequency dependent measurements of device characteristics indicate that neither interface defects nor deep traps are dominant for the charging or discharging processes of nanocrystal floating gates.

  11. Non-volatile flash memory with discrete bionanodot floating gate assembled by protein template.

    PubMed

    Miura, Atsushi; Tsukamoto, Rikako; Yoshii, Shigeo; Yamashita, Ichiro; Uraoka, Yukiharu; Fuyuki, Takashi

    2008-06-25

    We demonstrated non-volatile flash memory fabrication by utilizing uniformly sized cobalt oxide (Co(3)O(4)) bionanodot (Co-BND) architecture assembled by a cage-shaped supramolecular protein template. A fabricated high-density Co-BND array was buried in a metal-oxide-semiconductor field-effect-transistor (MOSFET) structure to use as the charge storage node of a floating nanodot gate memory. We observed a clockwise hysteresis in the drain current-gate voltage characteristics of fabricated BND-embedded MOSFETs. Observed hysteresis obviously indicates a memory operation of Co-BND-embedded MOSFETs due to the charge confinement in the embedded BND and successful functioning of embedded BNDs as the charge storage nodes of the non-volatile flash memory. Fabricated Co-BND-embedded MOSFETs showed good memory properties such as wide memory windows, long charge retention and high tolerance to repeated write/erase operations. A new pathway for device fabrication by utilizing the versatile functionality of biomolecules is presented.

  12. Organic ferroelectric gate field-effect transistor memory using high-mobility rubrene thin film

    NASA Astrophysics Data System (ADS)

    Kanashima, Takeshi; Katsura, Yuu; Okuyama, Masanori

    2014-01-01

    An organic ferroelectric gate field-effect transistor (FET) memory has been fabricated using an organic semiconductor of rubrene thin film with a high mobility and a gate insulating layer of poly(vinylidene fluoride-tetrafluoroethylene) [P(VDF-TeFE)] thin film. A rubrene thin-film sheet was grown by physical vapor transport (PVT), and placed onto a spin-coated P(VDF-TeFE) thin-film layer, and Au source and drain electrodes were formed on this rubrene thin film. A hysteresis loop of the drain current-gate voltage (ID-VG) characteristic has been clearly observed in the ferroelectric gate FET, and is caused by the ferroelectricity. The maximum drain current is 1.5 × 10-6 A, which is about two orders of magnitude larger than that of the P(VDF-TeFE) gate FET using a pentacene thin film. Moreover, the mobility of this organic ferroelectric gate FET using rubrene thin film is 0.71 cm2 V-1 s-1, which is 35 times larger than that of the FET with pentacene thin film.

  13. Gate Annealing of Cycling Endurance and Interface States for Highly Reliable Flash Memory

    NASA Astrophysics Data System (ADS)

    Kim, Nam-Kyeong; Hong, Se-Hee; Shim, Sa-Yong; Park, Min-Hee; Hwang, Kyung-Pil; Lee, Min-Kyu; Lee, Ju-Yeab; Woo, Won-Sic; Noh, Keum-Hwan; Lee, Hee-Kee; Om, Jae-Chul; Lee, Seok-Kiu; Bae, Gi-Hyun

    2008-01-01

    We report on superior cycling endurance due to a low interface trap density, which accounts for the high gate annealing temperature in flash memory. The interface trap density was characterized using a charge pumping method (CPM). The cycling VTH shift in an erase state value of 1.35 V at 850 °C temperature of an annealing, as measured on a 90-nm-technology 1-Mbit cell array, selected randomly from 1 Gbit cells, drops to less than 0.9 V after annealing at 950 °C. These superior electrical properties resulted from a complete relaxation of silicon interface trap charges due to a plasma-induced attack during gate annealing at temperatures over 950 °C for a long time. Therefore, the key factor for highly reliable endurance with cycling is believed to be the interface trap control of the thermal annealing carried out after gate etching.

  14. Time-dependent molecular memory in single voltage-gated sodium channel.

    PubMed

    Nayak, Tapan K; Sikdar, S K

    2007-10-01

    Excitability in neurons is associated with firing of action potentials and requires the opening of voltage-gated sodium channels with membrane depolarization. Sustained membrane depolarization, as seen in pathophysiological conditions like epilepsy, can have profound implications on the biophysical properties of voltage-gated ion channels. Therefore, we sought to characterize the effect of sustained membrane depolarization on single voltage-gated Na+ channels. Single-channel activity was recorded in the cell-attached patch-clamp mode from the rNa(v)1.2 alpha channels expressed in CHO cells. Classical statistical analysis revealed complex nonlinear changes in channel dwell times and unitary conductance of single Na+ channels as a function of conditioning membrane depolarization. Signal processing tools like weighted wavelet Z (WWZ) and discrete Fourier transform analyses attributed a "pseudo-oscillatory" nature to the observed nonlinear variation in the kinetic parameters. Modeling studies using the hidden Markov model (HMM) illustrated significant changes in kinetic states and underlying state transition rate constants upon conditioning depolarization. Our results suggest that sustained membrane depolarization induces novel nonlinear properties in voltage-gated Na+ channels. Prolonged membrane depolarization also induced a "molecular memory" phenomenon, characterized by clusters of dwell time events and strong autocorrelation in the dwell time series similar to that reported recently for single enzyme molecules. The persistence of such molecular memory was found to be dependent on the duration of depolarization. Voltage-gated Na+ channel with the observed time-dependent nonlinear properties and the molecular memory phenomenon may determine the functional state of the channel and, in turn, the excitability of a neuron.

  15. Physical implication of transition voltage in organic nano-floating-gate nonvolatile memories

    NASA Astrophysics Data System (ADS)

    Wang, Shun; Gao, Xu; Zhong, Ya-Nan; Zhang, Zhong-Da; Xu, Jian-Long; Wang, Sui-Dong

    2016-07-01

    High-performance pentacene-based organic field-effect transistor nonvolatile memories, using polystyrene as a tunneling dielectric and Au nanoparticles as a nano-floating-gate, show parallelogram-like transfer characteristics with a featured transition point. The transition voltage at the transition point corresponds to a threshold electric field in the tunneling dielectric, over which stored electrons in the nano-floating-gate will start to leak out. The transition voltage can be modulated depending on the bias configuration and device structure. For p-type active layers, optimized transition voltage should be on the negative side of but close to the reading voltage, which can simultaneously achieve a high ON/OFF ratio and good memory retention.

  16. Investigation of High-k Dielectrics and Metal Gate Electrodes for Non-volatile Memory Applications

    NASA Astrophysics Data System (ADS)

    Jayanti, Srikant

    Due to the increasing demand of non-volatile flash memories in the portable electronics, the device structures need to be scaled down drastically. However, the scalability of traditional floating gate structures beyond 20 nm NAND flash technology node is uncertain. In this regard, the use of metal gates and high-k dielectrics as the gate and interpoly dielectrics respectively, seem to be promising substitutes in order to continue the flash scaling beyond 20nm. Furthermore, research of novel memory structures to overcome the scaling challenges need to be explored. Through this work, the use of high-k dielectrics as IPDs in a memory structure has been studied. For this purpose, IPD process optimization and barrier engineering were explored to determine and improve the memory performance. Specifically, the concept of high-k / low-k barrier engineering was studied in corroboration with simulations. In addition, a novel memory structure comprising a continuous metal floating gate was investigated in combination with high-k blocking oxides. Integration of thin metal FGs and high-k dielectrics into a dual floating gate memory structure to result in both volatile and non-volatile modes of operation has been demonstrated, for plausible application in future unified memory architectures. The electrical characterization was performed on simple MIS/MIM and memory capacitors, fabricated through CMOS compatible processes. Various analytical characterization techniques were done to gain more insight into the material behavior of the layers in the device structure. In the first part of this study, interfacial engineering was investigated by exploring La2O3 as SiO2 scavenging layer. Through the silicate formation, the consumption of low-k SiO2 was controlled and resulted in a significant improvement in dielectric leakage. The performance improvement was also gauged through memory capacitors. In the second part of the study, a novel memory structure consisting of continuous metal FG

  17. Reliability study of retention and memory gate integrity in a 1K MNOS RAM

    SciTech Connect

    Nasby, R.D.; Miller, W.M.; White, R.L.

    1986-01-01

    The reliability of a 1K MNOS RAM with regards to retention and nitride gate integrity has been demonstrated. Over 400 devices were screened and life tested to demonstrate 0.999 reliability during device life. The device was a 1K MNOS memory used in a RAM application with an erase/write cycle of 32 microseconds and a life specification of 1E7 cycles.

  18. Single layer of Ge quantum dots in HfO2 for floating gate memory capacitors.

    PubMed

    Lepadatu, A M; Palade, C; Slav, A; Maraloiu, A V; Lazanu, S; Stoica, T; Logofatu, C; Teodorescu, V S; Ciurea, M L

    2017-04-28

    High performance trilayer memory capacitors with a floating gate of a single layer of Ge quantum dots (QDs) in HfO2 were fabricated using magnetron sputtering followed by rapid thermal annealing (RTA). The layer sequence of the capacitors is gate HfO 2/floating gate of single layer of Ge QDs in HfO 2/tunnel HfO 2/p-Si wafers. Both Ge and HfO2 are nanostructured by RTA at moderate temperatures of 600-700 °C. By nanostructuring at 600 °C, the formation of a single layer of well separated Ge QDs with diameters of 2-3 nm at a density of 4-5 × 10(15) m(-2) is achieved in the floating gate (intermediate layer). The Ge QDs inside the intermediate layer are arranged in a single layer and are separated from each other by HfO2 nanocrystals (NCs) about 8 nm in diameter with a tetragonal/orthorhombic structure. The Ge QDs in the single layer are located at the crossing of the HfO2 NCs boundaries. In the intermediate layer, besides Ge QDs, a part of the Ge atoms is segregated by RTA at the HfO2 NCs boundaries, while another part of the Ge atoms is present inside the HfO2 lattice stabilizing the tetragonal/orthorhombic structure. The fabricated capacitors show a memory window of 3.8 ± 0.5 V and a capacitance-time characteristic with 14% capacitance decay in the first 3000-4000 s followed by a very slow capacitance decrease extrapolated to 50% after 10 years. This high performance is mainly due to the floating gate of a single layer of well separated Ge QDs in HfO2, distanced from the Si substrate by the tunnel oxide layer with a precise thickness.

  19. Comparison of floating gate neural network memory cells in standard VLSI CMOS technology.

    PubMed

    Durfee, D A; Shoucair, F S

    1992-01-01

    Several floating gate MOSFET structures, for potential use as analog memory elements in neural networks, have been fabricated in a standard 2 mum double-polysilicon CMOS process. Their physical and programming characteristics are compared with each other and with similar structures reported in the literature. None of the circuits under consideration require special fabrication techniques. The criteria used to determine the structure most suitable for neural network memory applications include the symmetry of charging and discharging characteristics, programming voltage magnitudes, the area required, and the effectiveness of geometric field enhancement techniques. This work provides a layout for an analog neural network memory based on previously unexplored criteria and results. The authors have found that the best designs (a) use the poly1 to poly2 oxide for injection; (b) need not utilize ;field enhancement' techniques; (c) use poly1 to diffusion oxide for a coupling capacitor; and (d) size capacitor ratios to provide a wide range of possible programming voltages.

  20. Gate contact resistive random access memory in nano scaled FinFET logic technologies

    NASA Astrophysics Data System (ADS)

    Hsu, Meng-Yin; Shih, Yi-Hong; Chih, Yue-Der; Lin, Chrong Jung; King, Ya-Chin

    2017-04-01

    A full logic-compatible embedded gate contact resistive random access memory (GC-RRAM) cell in the CMOS FinFET logic process without extra mask or processing steps has been successfully demonstrated for high-density and low-cost logic nonvolatile memory (NVM) applications. This novel GC-RRAM cell is composed of a transition metal oxide from the gate contact plug and interlayer dielectric (ILD) in the middle, and a gate contact and an n-type epitaxial drain terminal as the top and bottom electrodes, respectively. It features low-voltage operation and reset current, compact cell size, and a stable read window. As a promising embedded NVM solution, the compact one transistor and one resistor (1T1R) cell is highly scalable as the technology node progresses. Excellent data retention and cycling capability have also been demonstrated by the reliability testing results. These superior characteristics make GC-RRAM one of a few viable candidates for logic NVM for future FinFET circuits.

  1. Stretchable carbon nanotube charge-trap floating-gate memory and logic devices for wearable electronics.

    PubMed

    Son, Donghee; Koo, Ja Hoon; Song, Jun-Kyul; Kim, Jaemin; Lee, Mincheol; Shim, Hyung Joon; Park, Minjoon; Lee, Minbaek; Kim, Ji Hoon; Kim, Dae-Hyeong

    2015-05-26

    Electronics for wearable applications require soft, flexible, and stretchable materials and designs to overcome the mechanical mismatch between the human body and devices. A key requirement for such wearable electronics is reliable operation with high performance and robustness during various deformations induced by motions. Here, we present materials and device design strategies for the core elements of wearable electronics, such as transistors, charge-trap floating-gate memory units, and various logic gates, with stretchable form factors. The use of semiconducting carbon nanotube networks designed for integration with charge traps and ultrathin dielectric layers meets the performance requirements as well as reliability, proven by detailed material and electrical characterizations using statistics. Serpentine interconnections and neutral mechanical plane layouts further enhance the deformability required for skin-based systems. Repetitive stretching tests and studies in mechanics corroborate the validity of the current approaches.

  2. Relating Hippocampus to Relational Memory Processing across Domains and Delays

    PubMed Central

    Monti, Jim M.; Cooke, Gillian E.; Watson, Patrick D.; Voss, Michelle W.; Kramer, Arthur F.; Cohen, Neal J.

    2015-01-01

    The hippocampus has been implicated in a diverse set of cognitive domains and paradigms, including cognitive mapping, long-term memory, and relational memory, at long or short study–test intervals. Despite the diversity of these areas, their association with the hippocampus may rely on an underlying commonality of relational memory processing shared among them. Most studies assess hippocampal memory within just one of these domains, making it difficult to know whether these paradigms all assess a similar underlying cognitive construct tied to the hippocampus. Here we directly tested the commonality among disparate tasks linked to the hippocampus by using PCA on performance from a battery of 12 cognitive tasks that included two traditional, long-delay neuropsychological tests of memory and two laboratory tests of relational memory (one of spatial and one of visual object associations) that imposed only short delays between study and test. Also included were different tests of memory, executive function, and processing speed. Structural MRI scans from a subset of participants were used to quantify the volume of the hippocampus and other subcortical regions. Results revealed that the 12 tasks clustered into four components; critically, the two neuropsychological tasks of long-term verbal memory and the two laboratory tests of relational memory loaded onto one component. Moreover, bilateral hippocampal volume was strongly tied to performance on this component. Taken together, these data emphasize the important contribution the hippocampus makes to relational memory processing across a broad range of tasks that span multiple domains. PMID:25203273

  3. Relating hippocampus to relational memory processing across domains and delays.

    PubMed

    Monti, Jim M; Cooke, Gillian E; Watson, Patrick D; Voss, Michelle W; Kramer, Arthur F; Cohen, Neal J

    2015-02-01

    The hippocampus has been implicated in a diverse set of cognitive domains and paradigms, including cognitive mapping, long-term memory, and relational memory, at long or short study-test intervals. Despite the diversity of these areas, their association with the hippocampus may rely on an underlying commonality of relational memory processing shared among them. Most studies assess hippocampal memory within just one of these domains, making it difficult to know whether these paradigms all assess a similar underlying cognitive construct tied to the hippocampus. Here we directly tested the commonality among disparate tasks linked to the hippocampus by using PCA on performance from a battery of 12 cognitive tasks that included two traditional, long-delay neuropsychological tests of memory and two laboratory tests of relational memory (one of spatial and one of visual object associations) that imposed only short delays between study and test. Also included were different tests of memory, executive function, and processing speed. Structural MRI scans from a subset of participants were used to quantify the volume of the hippocampus and other subcortical regions. Results revealed that the 12 tasks clustered into four components; critically, the two neuropsychological tasks of long-term verbal memory and the two laboratory tests of relational memory loaded onto one component. Moreover, bilateral hippocampal volume was strongly tied to performance on this component. Taken together, these data emphasize the important contribution the hippocampus makes to relational memory processing across a broad range of tasks that span multiple domains.

  4. Stable charge storing in two-dimensional MoS2 nanoflake floating gates for multilevel organic flash memory

    NASA Astrophysics Data System (ADS)

    Kang, Minji; Kim, Yeong-A.; Yun, Jin-Mun; Khim, Dongyoon; Kim, Jihong; Noh, Yong-Young; Baeg, Kang-Jun; Kim, Dong-Yu

    2014-10-01

    In this study, we investigated chemically exfoliated two-dimensional (2-D) nanoflakes of molybdenum disulfide (MoS2) as charge-storing elements for use in organic multilevel memory devices (of the printed/flexible non-volatile type) based on organic field-effect transistors (OFETs) containing poly(3-hexylthiophene) (P3HT). The metallic MoS2 nanoflakes were exfoliated in 2-methoxyethanol by the lithium intercalation method and were deposited as nano-floating gates between polystyrene and poly(methyl methacrylate), used as bilayered gate dielectrics, by a simple spin-coating and low temperature (<150 °C) process. In the developed OFET memory devices, electrons could be trapped/detrapped in the MoS2 nano-floating gates by modulating the charge carrier density in the active channel through gate bias control. Optimal memory characteristics were achieved by controlling the thickness and concentration of few-layered MoS2 nanoflakes, and the best device showed reliable non-volatile memory properties: a sufficient memory window of ~23 V, programming-reading-erasing cycling endurance of >102 times, and most importantly, quasi-permanent charge-storing characteristics, i.e., a very long retention time (longer than the technological requirement of commercial memory devices (>10 years)). In addition, we successfully developed multilevel memory cells (2 bits per cell) by controlling the gate bias magnitude.In this study, we investigated chemically exfoliated two-dimensional (2-D) nanoflakes of molybdenum disulfide (MoS2) as charge-storing elements for use in organic multilevel memory devices (of the printed/flexible non-volatile type) based on organic field-effect transistors (OFETs) containing poly(3-hexylthiophene) (P3HT). The metallic MoS2 nanoflakes were exfoliated in 2-methoxyethanol by the lithium intercalation method and were deposited as nano-floating gates between polystyrene and poly(methyl methacrylate), used as bilayered gate dielectrics, by a simple spin-coating and

  5. Organic Nano-Floating-Gate Memory with Polymer:[6,6]-Phenyl-C61 Butyric Acid Methyl Ester Composite Films

    NASA Astrophysics Data System (ADS)

    Kang-Jun Baeg,; Dongyoon Khim,; Dong-Yu Kim,; Soon-Won Jung,; Jae Bon Koo,; Yong-Young Noh,

    2010-05-01

    Here, we report on a pentacene-based, nonvolatile transistor memory device with poly(4-vinyl phenol) (PVP):[6,6]-phenyl-C61 butyric acid methyl ester (PCBM) nano-composite films as the charge storage site. Incorporation of PCBM molecules into PVP dielectric materials as charge storage sites for electrons resulted in a reversible shift in the threshold voltage (VTh) and reliable memory characteristics. The characteristics of the pentacene memory device were as follows: a relatively high field-effect mobility (μFET) (0.2-0.3 cm2 V-1 s-1) with a large memory window (ca. 20 V), a high on/off ratio (˜104) during writing and erasing with application of an operating gate voltage of 60 V for a short duration time (˜1 ms), and a retention time of about 40 h.

  6. Organic Nano-Floating-Gate Memory with Polymer:[6,6]-Phenyl-C61 Butyric Acid Methyl Ester Composite Films

    NASA Astrophysics Data System (ADS)

    Baeg, Kang-Jun; Khim, Dongyoon; Kim, Dong-Yu; Jung, Soon-Won; Bon Koo, Jae; Noh, Yong-Young

    2010-05-01

    Here, we report on a pentacene-based, nonvolatile transistor memory device with poly(4-vinyl phenol) (PVP):[6,6]-phenyl-C61 butyric acid methyl ester (PCBM) nano-composite films as the charge storage site. Incorporation of PCBM molecules into PVP dielectric materials as charge storage sites for electrons resulted in a reversible shift in the threshold voltage (VTh) and reliable memory characteristics. The characteristics of the pentacene memory device were as follows: a relatively high field-effect mobility (µFET) (0.2-0.3 cm2 V-1 s-1) with a large memory window (ca. 20 V), a high on/off ratio (˜104) during writing and erasing with application of an operating gate voltage of 60 V for a short duration time (˜1 ms), and a retention time of about 40 h.

  7. Quantum memory and phase gate in Optical cavities based on EIT

    NASA Astrophysics Data System (ADS)

    Borges, Halyne; Villas-Bôas, Celso

    In this work we investigate theoretically the implementation of an optical quantum memory in a system composed by a single atom, trapped in a high finesse optical cavity. In order to analyse the feasibility of implementing a quantum memory in the atom-cavity system based on the EIT phenomenon, we investigated in detail which parameter configuration the memory efficiency is optimized considering the two different setups. Our results shows that for a asymmetric one-sided cavity, which is the experimental setup commonly used to observe the EIT effect, the memory efficiency value saturates at about 8 . 5 % . Meanwhile, for an one-sided cavity, we observe for a sufficiently high value of the coupling constant g, the efficiency has its maximum value increased considerably, close to 100 % . However, this experimental setup is not suitable to observe cavity-EIT in the transmission spectrum, being necessary another kind of experiment, such as measurements phase difference field that leaves the cavity induced by the control field. Considering this configuration we also showed the implementation of a quantum phase gate based on the same nonlinear effect, where the pulse probe can experience a phase shift on the order of π, due to the presence or absence of a control pulse. Supported by FAPESP (Proc. 2014/12740-1) and INCT-IQ.

  8. Event-related Potential Signatures of Relational Memory

    PubMed Central

    Hannula, Deborah E.; Federmeier, Kara D.; Cohen, Neal J.

    2009-01-01

    Various lines of evidence suggest that memory for the relations among arbitrarily paired items acquired prior to testing can influence early processing of a probe stimulus. The event-related potential experiment reported here was designed to explore how early in time memory for a previously established face-scene relationship begins to influence processing of faces, under sequential presentation conditions in which a preview of the scene can promote expectancies about the to-be-presented face. Prior to the current work, the earliest component documented to be sensitive to memory for the relations among arbitrarily paired items was the late positive complex (LPC), but here relational memory effects were evident as early as 270-350 msec after face onset. The latency of these relational memory effects suggests that they may be the precursor to similar effects observed in eye movement behavior. As expected, LPC amplitude was also affected by memory for face-scene relationships, and N400 amplitude reflected some combination of memory for items and memory for the relations among items. PMID:17069477

  9. Spatial Relational Memory Requires Hippocampal Adult Neurogenesis

    PubMed Central

    Koehl, Muriel; Ichas, François; De Giorgi, Francesca; Costet, Pierre; Abrous, Djoher Nora; Piazza, Pier Vincenzo

    2008-01-01

    The dentate gyrus of the hippocampus is one of the few regions of the mammalian brain where new neurons are generated throughout adulthood. This adult neurogenesis has been proposed as a novel mechanism that mediates spatial memory. However, data showing a causal relationship between neurogenesis and spatial memory are controversial. Here, we developed an inducible transgenic strategy allowing specific ablation of adult-born hippocampal neurons. This resulted in an impairment of spatial relational memory, which supports a capacity for flexible, inferential memory expression. In contrast, less complex forms of spatial knowledge were unaltered. These findings demonstrate that adult-born neurons are necessary for complex forms of hippocampus-mediated learning. PMID:18509506

  10. Novel process for widening memory window of sub-200 nm ferroelectric-gate field-effect transistor by ferroelectric coating the gate-stack sidewall

    NASA Astrophysics Data System (ADS)

    Van Hai, Le; Takahashi, Mitsue; Zhang, Wei; Sakai, Shigeki

    2015-01-01

    Ferroelectric-gate field-effect transistors (FeFETs) with metallurgical-gate lengths of 140 nm, 160 nm and 190 nm were successfully fabricated using a novel fabrication process. The gate stacks of the FeFETs were Pt/Sr0.8Ca0.2Bi2Ta2O9(SCBT)/HfO2/Si. Key to the process was covering the as-etched gate-stack sidewalls with SCBT precursor films and annealing altogether. The FeFETs which underwent the novel process showed larger memory windows than those without the process by about 0.5 V at scanned gate-voltages of 1 ± 5 V. Endurances of the FeFETs made by the novel process were measured up to 109 cycles with good separations of the on- and off-states. The endurance pulses were 1 ± 5 V with 2 μs period. Good data-retentions of them were also demonstrated which were measured for at least 6.5 days.

  11. A semi-floating gate transistor for low-voltage ultrafast memory and sensing operation.

    PubMed

    Wang, Peng-Fei; Lin, Xi; Liu, Lei; Sun, Qing-Qing; Zhou, Peng; Liu, Xiao-Yong; Liu, Wei; Gong, Yi; Zhang, David Wei

    2013-08-09

    As the semiconductor devices of integrated circuits approach the physical limitations of scaling, alternative transistor and memory designs are needed to achieve improvements in speed, density, and power consumption. We report on a transistor that uses an embedded tunneling field-effect transistor for charging and discharging the semi-floating gate. This transistor operates at low voltages (≤2.0 volts), with a large threshold voltage window of 3.1 volts, and can achieve ultra-high-speed writing operations (on time scales of ~1 nanosecond). A linear dependence of drain current on light intensity was observed when the transistor was exposed to light, so possible applications include image sensing with high density and performance.

  12. The floating-gate non-volatile semiconductor memory--from invention to the digital age.

    PubMed

    Sze, S M

    2012-10-01

    In the past 45 years (from 1967 to 2012), the non-volatile semiconductor memory (NVSM) has emerged from a floating-gate concept to the prime technology driver of the largest industry in the world-the electronics industry. In this paper, we briefly review the historical development of NVSM and project its future trends to the year 2020. In addition, we consider NVSM's wide-range of applications from the digital cellular phone to tablet computer to digital television. As the device dimension is scaled down to the deca-nanometer regime, we expect that many innovations will be made to meet the scaling challenges, and NVSM-inspired technology will continue to enrich and improve our lives for decades to come.

  13. Transparent photostable ZnO nonvolatile memory transistor with ferroelectric polymer and sputter-deposited oxide gate

    NASA Astrophysics Data System (ADS)

    Park, C. H.; Im, Seongil; Yun, Jungheum; Lee, Gun Hwan; Lee, Byoung H.; Sung, Myung M.

    2009-11-01

    We report on the fabrication of transparent top-gate ZnO nonvolatile memory thin-film transistors (NVM-TFTs) with 200 nm thick poly(vinylidene fluoride/trifluoroethylene) ferroelectric layer; semitransparent 10 nm thin AgOx and transparent 130 nm thick indium-zinc oxide (IZO) were deposited on the ferroelectric polymer as gate electrode by rf sputtering. Our semitransparent NVM-TFT with AgOx gate operates under low voltage write-erase (WR-ER) pulse of ±20 V, but shows some degradation in retention property. In contrast, our transparent IZO-gated device displays very good retention properties but requires anomalously higher pulse of ±70 V for WR and ER states. Both devices stably operated under visible illuminations.

  14. Transparent photostable ZnO nonvolatile memory transistor with ferroelectric polymer and sputter-deposited oxide gate

    SciTech Connect

    Park, C. H.; Im, Seongil; Yun, Jungheum; Lee, Gun Hwan; Lee, Byoung H.; Sung, Myung M.

    2009-11-30

    We report on the fabrication of transparent top-gate ZnO nonvolatile memory thin-film transistors (NVM-TFTs) with 200 nm thick poly(vinylidene fluoride/trifluoroethylene) ferroelectric layer; semitransparent 10 nm thin AgO{sub x} and transparent 130 nm thick indium-zinc oxide (IZO) were deposited on the ferroelectric polymer as gate electrode by rf sputtering. Our semitransparent NVM-TFT with AgO{sub x} gate operates under low voltage write-erase (WR-ER) pulse of {+-}20 V, but shows some degradation in retention property. In contrast, our transparent IZO-gated device displays very good retention properties but requires anomalously higher pulse of {+-}70 V for WR and ER states. Both devices stably operated under visible illuminations.

  15. Multi-layer high- κ interpoly dielectric for floating gate flash memory devices

    NASA Astrophysics Data System (ADS)

    Zhang, Lu; He, Wei; Chan, Daniel S. H.; Cho, Byung Jin

    2008-04-01

    We present a systematic simulation and experimental study of tunneling leakage current of the interpoly dielectric (IPD) layer in a floating gate (FG) type flash memory. IPD layers with different structural and material combinations such as HfLaO and 4% Tb-doped HfO 2 were studied. It is shown that compared with a conventional Al 2O 3-HfO 2-Al 2O 3 high-low-high barrier structure, the HfO 2-Al 2O 3-HfO 2 multilayer IPD stack with a low-high-low barrier structure has a lower leakage current due to the longer effective electron tunneling distance. Results also show that multilayer IPD structure has advantage of better thermal stability compared to the single layer IPD. Further work with simulations and experiments results suggest that the presence of a thin interfacial layer between polysilicon FG and IPD can increase the magnitude of leakage current by two or three orders. Nitridation of polysilicon floating gate reduced the leakage current by around two orders of magnitude at a constant equivalent oxide thickness. This is due to the elimination of the interfacial layer between polysilicon and high- κ IPD.

  16. Fabrication of arrayed Si nanowire-based nano-floating gate memory devices on flexible plastics.

    PubMed

    Yoon, Changjoon; Jeon, Youngin; Yun, Junggwon; Kim, Sangsig

    2012-01-01

    Arrayed Si nanowire (NW)-based nano-floating gate memory (NFGM) devices with Pt nanoparticles (NPs) embedded in Al2O3 gate layers are successfully constructed on flexible plastics by top-down approaches. Ten arrayed Si NW-based NFGM devices are positioned on the first level. Cross-linked poly-4-vinylphenol (PVP) layers are spin-coated on them as isolation layers between the first and second level, and another ten devices are stacked on the cross-linked PVP isolation layers. The electrical characteristics of the representative Si NW-based NFGM devices on the first and second levels exhibit threshold voltage shifts, indicating the trapping and detrapping of electrons in their NPs nodes. They have an average threshold voltage shift of 2.5 V with good retention times of more than 5 x 10(4) s. Moreover, most of the devices successfully retain their electrical characteristics after about one thousand bending cycles. These well-arrayed and stacked Si NW-based NFGM devices demonstrate the potential of nanowire-based devices for large-scale integration.

  17. Two-terminal floating-gate memory with van der Waals heterostructures for ultrahigh on/off ratio

    PubMed Central

    Vu, Quoc An; Shin, Yong Seon; Kim, Young Rae; Nguyen, Van Luan; Kang, Won Tae; Kim, Hyun; Luong, Dinh Hoa; Lee, Il Min; Lee, Kiyoung; Ko, Dong-Su; Heo, Jinseong; Park, Seongjun; Lee, Young Hee; Yu, Woo Jong

    2016-01-01

    Concepts of non-volatile memory to replace conventional flash memory have suffered from low material reliability and high off-state current, and the use of a thick, rigid blocking oxide layer in flash memory further restricts vertical scale-up. Here, we report a two-terminal floating gate memory, tunnelling random access memory fabricated by a monolayer MoS2/h-BN/monolayer graphene vertical stack. Our device uses a two-terminal electrode for current flow in the MoS2 channel and simultaneously for charging and discharging the graphene floating gate through the h-BN tunnelling barrier. By effective charge tunnelling through crystalline h-BN layer and storing charges in graphene layer, our memory device demonstrates an ultimately low off-state current of 10−14 A, leading to ultrahigh on/off ratio over 109, about ∼103 times higher than other two-terminal memories. Furthermore, the absence of thick, rigid blocking oxides enables high stretchability (>19%) which is useful for soft electronics. PMID:27586841

  18. Two-terminal floating-gate memory with van der Waals heterostructures for ultrahigh on/off ratio.

    PubMed

    Vu, Quoc An; Shin, Yong Seon; Kim, Young Rae; Nguyen, Van Luan; Kang, Won Tae; Kim, Hyun; Luong, Dinh Hoa; Lee, Il Min; Lee, Kiyoung; Ko, Dong-Su; Heo, Jinseong; Park, Seongjun; Lee, Young Hee; Yu, Woo Jong

    2016-09-02

    Concepts of non-volatile memory to replace conventional flash memory have suffered from low material reliability and high off-state current, and the use of a thick, rigid blocking oxide layer in flash memory further restricts vertical scale-up. Here, we report a two-terminal floating gate memory, tunnelling random access memory fabricated by a monolayer MoS2/h-BN/monolayer graphene vertical stack. Our device uses a two-terminal electrode for current flow in the MoS2 channel and simultaneously for charging and discharging the graphene floating gate through the h-BN tunnelling barrier. By effective charge tunnelling through crystalline h-BN layer and storing charges in graphene layer, our memory device demonstrates an ultimately low off-state current of 10(-14) A, leading to ultrahigh on/off ratio over 10(9), about ∼10(3) times higher than other two-terminal memories. Furthermore, the absence of thick, rigid blocking oxides enables high stretchability (>19%) which is useful for soft electronics.

  19. Two-terminal floating-gate memory with van der Waals heterostructures for ultrahigh on/off ratio

    NASA Astrophysics Data System (ADS)

    Vu, Quoc An; Shin, Yong Seon; Kim, Young Rae; Nguyen, Van Luan; Kang, Won Tae; Kim, Hyun; Luong, Dinh Hoa; Lee, Il Min; Lee, Kiyoung; Ko, Dong-Su; Heo, Jinseong; Park, Seongjun; Lee, Young Hee; Yu, Woo Jong

    2016-09-01

    Concepts of non-volatile memory to replace conventional flash memory have suffered from low material reliability and high off-state current, and the use of a thick, rigid blocking oxide layer in flash memory further restricts vertical scale-up. Here, we report a two-terminal floating gate memory, tunnelling random access memory fabricated by a monolayer MoS2/h-BN/monolayer graphene vertical stack. Our device uses a two-terminal electrode for current flow in the MoS2 channel and simultaneously for charging and discharging the graphene floating gate through the h-BN tunnelling barrier. By effective charge tunnelling through crystalline h-BN layer and storing charges in graphene layer, our memory device demonstrates an ultimately low off-state current of 10-14 A, leading to ultrahigh on/off ratio over 109, about ~103 times higher than other two-terminal memories. Furthermore, the absence of thick, rigid blocking oxides enables high stretchability (>19%) which is useful for soft electronics.

  20. Serotonergic Mechanisms in Addiction-Related Memories

    PubMed Central

    Nic Dhonnchadha, Bríd Á; Cunningham, Kathryn A.

    2008-01-01

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

  1. Dynamic memory of a single voltage-gated potassium ion channel: A stochastic nonequilibrium thermodynamic analysis

    NASA Astrophysics Data System (ADS)

    Banerjee, Kinshuk

    2015-05-01

    In this work, we have studied the stochastic response of a single voltage-gated potassium ion channel to a periodic external voltage that keeps the system out-of-equilibrium. The system exhibits memory, resulting from time-dependent driving, that is reflected in terms of dynamic hysteresis in the current-voltage characteristics. The hysteresis loop area has a maximum at some intermediate voltage frequency and disappears in the limits of low and high frequencies. However, the (average) dissipation at long-time limit increases and finally goes to saturation with rising frequency. This raises the question: how diminishing hysteresis can be associated with growing dissipation? To answer this, we have studied the nonequilibrium thermodynamics of the system and analyzed different thermodynamic functions which also exhibit hysteresis. Interestingly, by applying a temporal symmetry analysis in the high-frequency limit, we have analytically shown that hysteresis in some of the periodic responses of the system does not vanish. On the contrary, the rates of free energy and internal energy change of the system as well as the rate of dissipative work done on the system show growing hysteresis with frequency. Hence, although the current-voltage hysteresis disappears in the high-frequency limit, the memory of the ion channel is manifested through its specific nonequilibrium thermodynamic responses.

  2. Dynamic memory of a single voltage-gated potassium ion channel: A stochastic nonequilibrium thermodynamic analysis

    SciTech Connect

    Banerjee, Kinshuk

    2015-05-14

    In this work, we have studied the stochastic response of a single voltage-gated potassium ion channel to a periodic external voltage that keeps the system out-of-equilibrium. The system exhibits memory, resulting from time-dependent driving, that is reflected in terms of dynamic hysteresis in the current-voltage characteristics. The hysteresis loop area has a maximum at some intermediate voltage frequency and disappears in the limits of low and high frequencies. However, the (average) dissipation at long-time limit increases and finally goes to saturation with rising frequency. This raises the question: how diminishing hysteresis can be associated with growing dissipation? To answer this, we have studied the nonequilibrium thermodynamics of the system and analyzed different thermodynamic functions which also exhibit hysteresis. Interestingly, by applying a temporal symmetry analysis in the high-frequency limit, we have analytically shown that hysteresis in some of the periodic responses of the system does not vanish. On the contrary, the rates of free energy and internal energy change of the system as well as the rate of dissipative work done on the system show growing hysteresis with frequency. Hence, although the current-voltage hysteresis disappears in the high-frequency limit, the memory of the ion channel is manifested through its specific nonequilibrium thermodynamic responses.

  3. Investigation of charge trapping mechanism for nanocrystal-based organic nonvolatile floating gate memory devices by band structure analysis

    NASA Astrophysics Data System (ADS)

    Lee, Dong-Hoon; Lim, Ki-Tae; Park, Eung-Kyu; Shin, Ha-Chul; Kim, Chung Soo; Park, Kee-Chan; Ahn, Joung-Real; Bang, Jin Ho; Kim, Yong-Sang

    2016-05-01

    This paper investigates the charge trapping mechanism and electrical performance of CdSe nanocrystals, such as nanoparticles and nanowires in organic floating gate memory devices. Despite of same chemical component, each nanocrystals show different electrical performances with distinct trapping mechanism. CdSe nanoparticles trap holes in the memory device; on the contrary, nanowires trap electrons. This phenomenon is mainly due to the difference of energy band structures between nanoparticles and nanowires, measured by the ultraviolet photoelectron spectroscopy. Also, we investigated the memory performance with C- V characteristics, charging and discharging phenomena, and retention time. The nanoparticle based hole trapping memory device has large memory window while the nanowire based electron trapping memory shows a narrow memory window. In spite of narrow memory window, the nanowire based memory device shows better retention performance of about 55% of the charge even after 104 sec of charging. The contrasting performance of nanoparticle and nanowire is attributed to the difference in their energy band and the morphology of thin layer in the device. [Figure not available: see fulltext.

  4. FOREWORD: Shape Memory and Related Technologies

    NASA Astrophysics Data System (ADS)

    Liu, Yong

    2005-10-01

    The International Symposium on Shape Memory and Related Technologies (SMART2004) successfully took place in Singapore from November 24 to 26, 2004. SMART2004 aimed to provide a forum for presenting and discussing recent developments in the processing, characterization, application and performance prediction of shape memory materials, particularly shape memory alloys and magnetic shape memory materials. In recent years, we have seen a surge in the research and application of shape memory materials. This is due on the one hand to the successful applications of shape memory alloys (SMAs), particularly NiTi (nitinol), in medical practices and, on the other hand, to the discovery of magnetic shape memory (MSM) materials (or, ferromagnetic shape memory alloys, FSMAs). In recent years, applications of SMAs in various engineering practices have flourished owing to the unique combination of novel properties including high power density related to shape recovery, superelasticity with tunable hysteresis, high damping capacity combined with good fatigue resistance, excellent wear resistance due to unconventional deformation mechanisms (stress-induced phase transformation and martensite reorientation), and excellent biocompatibility and anticorrosion resistance, etc. In~the case of MSMs (or FSMAs), their giant shape change in a relatively low magnetic field has great potential to supplement the traditional actuation mechanisms and to have a great impact on the world of modern technology. Common mechanisms existing in both types of materials, namely thermoelastic phase transformation, martensite domain switching and their controlling factors, are of particular interest to the scientific community. Despite some successful applications, some fundamental issues remain unsatisfactorily understood. This conference hoped to link the fundamental research to engineering practices, and to further identify remaining problems in order to further promote the applications of shape memory

  5. Source-Bias Dependent Charge Accumulation in P+-Poly Gate SOI Dynamic Random Access Memory Cell Transistors

    NASA Astrophysics Data System (ADS)

    Sim, Jai-hoon; Kim, Kinam

    1998-03-01

    In this paper, we report the dynamic data retention problems caused by the transient leakage current in a cell transistor during the bit-line pull down operation in p+-poly gate fully depleted silicon-on-insulator (FD-SOI) dynamic random access memories (DRAMs) due to the source-induced charge accumulation (SICA) effect in the silicon thin film. Due to the inherent floating body effect in the FD-SOI transistor, charge accumulation in the silicon thin film becomes inevitable when the gate-to-source voltage (VGS) is smaller than the flat-band voltage (VFB). In order to eliminate the transient leakage current problem in p+-poly gate FD-SOI cell transistor, the ground-precharged bit-line (GPB) sensing method is introduced.

  6. Differential multiple-time-programmable memory cells by laterally coupled floating metal gate fin field-effect transistors

    NASA Astrophysics Data System (ADS)

    Hsu, Chia-Ling; Liao, Chu-Feng; Chien, Wei Yu; Chih, Yue-Der; Lin, Chrong Jung; King, Ya-Chin

    2017-04-01

    In this paper, we present a new differential multiple-time-programmable (MTP) memory cell with a novel slot contact coupling structure in the fin field-effect transistor (FinFET) CMOS process. This MTP cell contains a pair of floating metal gates to store differential data on a single cell. Through differential read operations, the cells are less susceptible to read error caused by cell-to-cell variations. In a nano-scaled FinFET process, the gate dielectric layer becomes too thin to retain charge in the floating gates for long periods of time. Differential cell design further extends the data lifetime, even with the serious charge-loss problem, and reduces the overall intellectual property (IP) area.

  7. Performance and reliability of HfAlO x-based interpoly dielectrics for floating-gate Flash memory

    NASA Astrophysics Data System (ADS)

    Govoreanu, B.; Wellekens, D.; Haspeslagh, L.; Brunco, D. P.; De Vos, J.; Aguado, D. Ruiz; Blomme, P.; van der Zanden, K.; Van Houdt, J.

    2008-04-01

    This paper discusses the performance and reliability of aggressively scaled HfAlO x-based interpoly dielectric stacks in combination with high-workfunction metal gates for sub-45 nm non-volatile memory technologies. It is shown that a less than 5 nm EOT IPD stack can provide a large program/erase (P/E) window, while operating at moderate voltages and has very good retention, with an extrapolated 10-year retention window of about 3 V at 150 °C. The impact of the process sequence and metal gate material is discussed. The viability of the material is considered in view of the demands of various Flash memory technologies and direction for further improvements are discussed.

  8. Numerical model of a single nanocrystal devoted to the study of disordered nanocrystal floating gates of new flash memories

    NASA Astrophysics Data System (ADS)

    Leroy, Yann; Armeanu, Dumitru; Cordan, Anne-Sophie

    2011-05-01

    The improvement of our model concerning a single nanocrystal that belongs to a nanocrystal floating gate of a flash memory is presented. In order to extend the gate voltage range applicability of the model, the 3D continuum of states of either metallic or semiconducting electrodes is discretized into 2D subbands. Such an approach gives precise information about the mechanisms behind the charging or release processes of the nanocrystal. Then, the self-energy and screening effects of an electron within the nanocrystal are evaluated and introduced in the model. This enables a better determination of the operating point of the nanocrystal memory. The impact of those improvements on the charging or release time of the nanocrystal is discussed.

  9. A nonvolatile memory device made of a ferroelectric polymer gate nanodot and a single-walled carbon nanotube.

    PubMed

    Son, Jong Yeog; Ryu, Sangwoo; Park, Yoon-Cheol; Lim, Yun-Tak; Shin, Yun-Sok; Shin, Young-Han; Jang, Hyun Myung

    2010-12-28

    We demonstrate a field-effect nonvolatile memory device made of a ferroelectric copolymer gate nanodot and a single-walled carbon nanotube (SW-CNT). A position-controlled dip-pen nanolithography was performed to deposit a poly(vinylidene fluoride-ran-trifluoroethylene) (PVDF-TrFE) nanodot onto the SW-CNT channel with both a source and drain for field-effect transistor (FET) function. PVDF-TrFE was chosen as a gate dielectric nanodot in order to efficiently exploit its bipolar chemical nature. A piezoelectric force microscopy study confirmed the canonical ferroelectric responses of the PVDF-TrFE nanodot fabricated at the center of the SW-CNT channel. The two distinct ferroelectric polarization states with the stable current retention and fatigue-resistant characteristics make the present PVDF-TrFE-based FET suitable for nonvolatile memory applications.

  10. Nonvolatile “AND,” “OR,” and “NOT” Boolean logic gates based on phase-change memory

    SciTech Connect

    Li, Y.; Zhong, Y. P.; Deng, Y. F.; Zhou, Y. X.; Xu, L.; Miao, X. S.

    2013-12-21

    Electronic devices or circuits that can implement both logic and memory functions are regarded as the building blocks for future massive parallel computing beyond von Neumann architecture. Here we proposed phase-change memory (PCM)-based nonvolatile logic gates capable of AND, OR, and NOT Boolean logic operations verified in SPICE simulations and circuit experiments. The logic operations are parallel computing and results can be stored directly in the states of the logic gates, facilitating the combination of computing and memory in the same circuit. These results are encouraging for ultralow-power and high-speed nonvolatile logic circuit design based on novel memory devices.

  11. Additive-Driven Assembly of Block Copolymer-Nanoparticle Hybrid Materials for Solution Processable Floating Gate Memory

    NASA Astrophysics Data System (ADS)

    Wei, Qingshuo; Lin, Ying; Anderson, Eric; Briseno, Alejandro; Gido, Samuel; Watkins, James

    2012-02-01

    The preparation of well-ordered hybrid materials at nanoscale is not only fundamentally interesting but also of significant importance for the development of next generation functional devices. In this study, we present a simple approach for the preparation of well-ordered polymer/NP composites through the concept of additive-driven assembly, and its application for the fabrication of floating gate organic FET memory devices. The addition of gold NPs that selectively hydrogen bond with pyridine in poly(styrene-b-2-vinyl pyridine) is shown to induce an ordered structure. This enables the fabrication of well-ordered hybrid materials with lamellar domains at Au NP loadings of more than 40 wt%. The fabrication of floating gate memory devices was demonstrated by the ordered Au NPs / block copolymer hybrid film as a charge trapping layer, which is sandwiched between a SiO2 dielectric layer and a poly(3-hexylthiophene) semiconductor layer. This approach enables us to fabricate well-ordered charge storage layers by solution processing and to achieve facile control of the memory windows by changing the density of gold NPs. The devices show high carrier mobility (> 0.1 cm^2/Vs), controllable memory windows (0˜50V), high on/off ratio (>10^5) between memory states and long retention times (>10^4 s). This approach is potentially suitable for roll-to-roll printing techniques to make flexible, large area and high density devices.

  12. Hippocampal amnesia impairs all manner of relational memory.

    PubMed

    Konkel, Alex; Warren, David E; Duff, Melissa C; Tranel, Daniel N; Cohen, Neal J

    2008-01-01

    Relational memory theory holds that the hippocampus supports, and amnesia following hippocampal damage impairs, memory for all manner of relations. Unfortunately, many studies of hippocampal-dependent memory have either examined only a single type of relational memory or conflated multiple kinds of relations. The experiments reported here employed a procedure in which each of several kinds of relational memory (spatial, associative, and sequential) could be tested separately using the same materials. In Experiment 1, performance of amnesic patients with medial temporal lobe (MTL) damage was assessed on memory for the three types of relations as well as for items. Compared to the performance of matched comparison participants, amnesic patients were impaired on all three relational tasks. But for those patients whose MTL damage was limited to the hippocampus, performance was relatively preserved on item memory as compared to relational memory, although still lower than that of comparison participants. In Experiment 2, study exposure was reduced for comparison participants, matching their item memory to the amnesic patients in Experiment 1. Relational memory performance of comparison subjects was well above amnesic patient levels, showing the disproportionate dependence of all three relational memory performances on the integrity of the hippocampus. Correlational analyses of the various task performances of comparison participants and of college-age participants showed that our measures of item memory were not influenced significantly by memory for associations among the items.

  13. The voltage-gated potassium channels and their relatives.

    PubMed

    Yellen, Gary

    2002-09-05

    The voltage-gated potassium channels are the prototypical members of a family of membrane signalling proteins. These protein-based machines have pores that pass millions of ions per second across the membrane with astonishing selectivity, and their gates snap open and shut in milliseconds as they sense changes in voltage or ligand concentration. The architectural modules and functional components of these sophisticated signalling molecules are becoming clear, but some important links remain to be elucidated.

  14. Control of Turing patterns and their usage as sensors, memory arrays, and logic gates

    NASA Astrophysics Data System (ADS)

    Muzika, František; Schreiber, Igor

    2013-10-01

    We study a model system of three diffusively coupled reaction cells arranged in a linear array that display Turing patterns with special focus on the case of equal coupling strength for all components. As a suitable model reaction we consider a two-variable core model of glycolysis. Using numerical continuation and bifurcation techniques we analyze the dependence of the system's steady states on varying rate coefficient of the recycling step while the coupling coefficients of the inhibitor and activator are fixed and set at the ratios 100:1, 1:1, and 4:5. We show that stable Turing patterns occur at all three ratios but, as expected, spontaneous transition from the spatially uniform steady state to the spatially nonuniform Turing patterns occurs only in the first case. The other two cases possess multiple Turing patterns, which are stabilized by secondary bifurcations and coexist with stable uniform periodic oscillations. For the 1:1 ratio we examine modular spatiotemporal perturbations, which allow for controllable switching between the uniform oscillations and various Turing patterns. Such modular perturbations are then used to construct chemical computing devices utilizing the multiple Turing patterns. By classifying various responses we propose: (a) a single-input resettable sensor capable of reading certain value of concentration, (b) two-input and three-input memory arrays capable of storing logic information, (c) three-input, three-output logic gates performing combinations of logical functions OR, XOR, AND, and NAND.

  15. Memory styles and related abilities in presentation of self.

    PubMed

    Sehulster, J R

    1995-01-01

    The notion of a person's memory style (elaborated in Sehulster, 1988) was investigated as it relates to the presentation of self. A memory style is defined as a combination of a subject's (perceived) ability in verbal memory, auto- biographical memory, and prospective memory, as measured by the Memory Scale (Sehulster, 1981b). In addition to filling out the Memory Scale, 325 subjects completed a 72-item questionnaire that tapped descriptions of abilities and experiences. The range of abilities and experiences was drawn loosely from Gardner's (1985) notion of multiple intelligences. Distinct patterns of self-report were observed for different memory styles. For instance, a love of listening to music was associated with the memory style that is high in both verbal and autobiographical memory but low in prospective memory; a love for numbers and mathematics was associated with the memory style that is high in both verbal and prospective memory but low in autobiographical memory. The results suggest broad individual differences in information processing. Gender differences are discussed in relation to memory styles.

  16. Highly compact and accurate circuit-level macro modeling of gate-all-around charge-trap flash memory

    NASA Astrophysics Data System (ADS)

    Kim, Seunghyun; Lee, Sang-Ho; Kim, Young-Goan; Cho, Seongjae; Park, Byung-Gook

    2017-01-01

    In this paper, a highly reliable circuit model of gate-all-around (GAA) charge-trap flash (CTF) memory cell is proposed, considering the transient behaviors for describing the program operations with improved accuracy. Although several compact models have been reported in the previous literature, time-dependent behaviors have not been precisely reflected and the failures tend to get worse as the operation time elapses. Furthermore, the developed SPICE models in this work have been verified by the measurement results of the fabricated flash memory cells having silicon-oxide-nitride-oxide-silicon (SONOS). This more realistic model would be beneficial in designing the system architectures and setting up the operation schemes for the leading three-dimensional (3D) stack CTF memory.

  17. Development of relational memory processes in monkeys.

    PubMed

    Alvarado, Maria C; Malkova, Ludise; Bachevalier, Jocelyne

    2016-12-01

    The present study tested whether relational memory processes, as measured by the transverse patterning problem, are late-developing in nonhuman primates as they are in humans. Eighteen macaques ranging from 3 to 36 months of age, were trained to solve a set of visual discriminations that formed the transverse patterning problem. Subjects were trained at 3, 4-6, 12, 15-24 or 36 months of age to solve three discriminations as follows: 1) A+ vs. B-; 2) B+ vs. C-; 3) C+ vs. A. When trained concurrently, subjects must adopt a relational strategy to perform accurately on all three problems. All 36 month old monkeys reached the criterion of 90% correct, but only one 24-month-old and one 15-month-old did, initially. Three-month-old infants performed at chance on all problems. Six and 12-month-olds performed at 75-80% correct but used a 'linear' or elemental solution (e.g. A>B>C), which only yields correct performance on two problems. Retraining the younger subjects at 12, 24 or 36 months yielded a quantitative improvement on speed of learning, and a qualitative improvement in 24-36 month old monkeys for learning strategy. The results suggest that nonspatial relational memory develops late in macaques (as in humans), maturing between 15 and 24 months of age.

  18. Simulation of quantum dot floating gate MOSFET memory performance using various high-k material as tunnel oxide

    NASA Astrophysics Data System (ADS)

    Aji, Adha Sukma; Darma, Yudi

    2012-06-01

    In this paper, performance of quantum dot floating gate MOSFET memory is simulated by replacing the SiO2 tunnel oxide with high-Κ material. There are three high-k material simulated in this paper, HfO2, ZrO2, and Y2O3. As we know that high-Κ material is used nowadays to reduce leakage current, so this paper demonstrates the application of high-Κ material to reduce leakage current in non-volatile memory quantum dot based floating gate MOSFET. Simulation results of this paper show the leakage current can be suppressed by using high-Κ material as tunnel oxide up to 10 times. Furthermore, this paper also shows that the memory performance can be properly sustained. The writing and erasing time are depend on tunneling current probability which calculated using transfer matrix method. The writing time and erasing time for HfO2 and ZrO2 are 150 nanosecond and 15 nanosecond.

  19. Characteristics of AgInSbTe-SiO2 nanocomposite thin film applied to nonvolatile floating gate memory devices.

    PubMed

    Chiang, Kuo-Chang; Hsieh, Tsung-Eong

    2010-10-22

    Nanocomposite thin films containing AgInSbTe (AIST) particles embedded in an SiO(2) matrix was prepared by sputtering deposition and its feasibility for nonvolatile floating gate memory (NFGM) was investigated. The sample subjected to a 400 °C annealing exhibited a distinct hysteresis memory window (ΔV(FB)) shift = 6.6 V and charge density = 5.2 × 10(12) cm(-2) after ± 8 V gate voltage sweep. Electrical measurement revealed the current transport is via the Schottky emission in low applied field and the space-charge-limited conduction mechanism in high applied field in the samples, regardless of their thermal history. Transmission electron microscopy and x-ray photoelectron spectroscopy indicated that the metallic Sb(2)Te nanocrystals (NCs) with diameters about 5-7 nm dispersed in a nanocomposite layer may serve as the discrete charge-storage traps for nonvolatile memory. Analytical results illustrate the utilization of an AIST-SiO(2) nanocomposite layer as the core structure of NFGM devices is able to simplify the device structure and fabrication process.

  20. Fabrication and Characterization of NOR-Type Tri-Gate Flash Memory with Improved Inter-Poly Dielectric Layer by Rapid Thermal Oxidation

    NASA Astrophysics Data System (ADS)

    Kamei, Takahiro; Liu, Yongxun; Matsukawa, Takashi; Endo, Kazuhiko; O'uchi, Shinichi; Tsukada, Junichi; Yamauchi, Hiromi; Ishikawa, Yuki; Hayashida, Tetsuro; Sakamoto, Kunihiro; Ogura, Atsushi; Masahara, Meishoku

    2012-06-01

    Floating-gate (FG)-type tri-gate flash memories with an improved inter-poly dielectric (IPD) layer have been successfully fabricated by introducing a newly developed rapid thermal oxidation (RTO) process, and their NOR-mode operation including threshold voltage (Vt) variations before and after one program/erase (P/E) cycle have been systematically investigated. It was experimentally confirmed that the gate breakdown voltage (BVg) is greatly increased from 12 to 19 V by introducing the RTO process thanks to the high quality and thin thermal silicon dioxide (SiO2) formation on the FG surface and etched edge regions, which effectively blocks the leakage pass of the IPD layer. A source-drain (SD) breakdown voltage (BVDS) as high as 4.5 V was obtained even when the gate length (Lg) was as small as 117 nm. It was also experimentally confirmed that the memory window increases with increasing gate voltage (Vg) in NOR-mode programming thanks to the increased efficiency of channel hot electron (CHE) injection. The developed tri-gate flash memory with improved IPD layer is useful for the further scaling of NOR-type flash memory.

  1. Cognitive mechanisms associated with auditory sensory gating.

    PubMed

    Jones, L A; Hills, P J; Dick, K M; Jones, S P; Bright, P

    2016-02-01

    Sensory gating is a neurophysiological measure of inhibition that is characterised by a reduction in the P50 event-related potential to a repeated identical stimulus. The objective of this work was to determine the cognitive mechanisms that relate to the neurological phenomenon of auditory sensory gating. Sixty participants underwent a battery of 10 cognitive tasks, including qualitatively different measures of attentional inhibition, working memory, and fluid intelligence. Participants additionally completed a paired-stimulus paradigm as a measure of auditory sensory gating. A correlational analysis revealed that several tasks correlated significantly with sensory gating. However once fluid intelligence and working memory were accounted for, only a measure of latent inhibition and accuracy scores on the continuous performance task showed significant sensitivity to sensory gating. We conclude that sensory gating reflects the identification of goal-irrelevant information at the encoding (input) stage and the subsequent ability to selectively attend to goal-relevant information based on that previous identification.

  2. Cognitive mechanisms associated with auditory sensory gating

    PubMed Central

    Jones, L.A.; Hills, P.J.; Dick, K.M.; Jones, S.P.; Bright, P.

    2016-01-01

    Sensory gating is a neurophysiological measure of inhibition that is characterised by a reduction in the P50 event-related potential to a repeated identical stimulus. The objective of this work was to determine the cognitive mechanisms that relate to the neurological phenomenon of auditory sensory gating. Sixty participants underwent a battery of 10 cognitive tasks, including qualitatively different measures of attentional inhibition, working memory, and fluid intelligence. Participants additionally completed a paired-stimulus paradigm as a measure of auditory sensory gating. A correlational analysis revealed that several tasks correlated significantly with sensory gating. However once fluid intelligence and working memory were accounted for, only a measure of latent inhibition and accuracy scores on the continuous performance task showed significant sensitivity to sensory gating. We conclude that sensory gating reflects the identification of goal-irrelevant information at the encoding (input) stage and the subsequent ability to selectively attend to goal-relevant information based on that previous identification. PMID:26716891

  3. Fabrication and characterization of non-volatile transistor memory based on polypeptide as gate dielectric

    NASA Astrophysics Data System (ADS)

    Liang, Lijuan; Li, LianFang; Wei, Xianfu; Huang, Beiqing; Wei, Yen

    2017-01-01

    The organic thin film transistor (OTFT) fabricated with the polypeptide as a dielectric layer shows memory function. In order to investigate the effect of polypeptide structure on the performance of non-volatile transistor memory, the Fourier-transform IR (FT- IR) and Circular Dichiroism (CD) spectral of PMLG film has been applied, respectively. In conclusion, the memory transistor device fabricated with polypeptide as the ferroelectric exhibit promising behavior such as a large memory window, and the dipole moment of the amide group was considered as the main source of the memory function.

  4. Sparse distributed memory and related models

    NASA Technical Reports Server (NTRS)

    Kanerva, Pentti

    1992-01-01

    Described here is sparse distributed memory (SDM) as a neural-net associative memory. It is characterized by two weight matrices and by a large internal dimension - the number of hidden units is much larger than the number of input or output units. The first matrix, A, is fixed and possibly random, and the second matrix, C, is modifiable. The SDM is compared and contrasted to (1) computer memory, (2) correlation-matrix memory, (3) feet-forward artificial neural network, (4) cortex of the cerebellum, (5) Marr and Albus models of the cerebellum, and (6) Albus' cerebellar model arithmetic computer (CMAC). Several variations of the basic SDM design are discussed: the selected-coordinate and hyperplane designs of Jaeckel, the pseudorandom associative neural memory of Hassoun, and SDM with real-valued input variables by Prager and Fallside. SDM research conducted mainly at the Research Institute for Advanced Computer Science (RIACS) in 1986-1991 is highlighted.

  5. The organisation of spatial and temporal relations in memory.

    PubMed

    Rondina, Renante; Curtiss, Kaitlin; Meltzer, Jed A; Barense, Morgan D; Ryan, Jennifer D

    2017-04-01

    Episodic memories are comprised of details of "where" and "when"; spatial and temporal relations, respectively. However, evidence from behavioural, neuropsychological, and neuroimaging studies has provided mixed interpretations about how memories for spatial and temporal relations are organised-they may be hierarchical, fully interactive, or independent. In the current study, we examined the interaction of memory for spatial and temporal relations. Using explicit reports and eye-tracking, we assessed younger and older adults' memory for spatial and temporal relations of objects that were presented singly across time in unique spatial locations. Explicit change detection of spatial relations was affected by a change in temporal relations, but explicit change detection of temporal relations was not affected by a change in spatial relations. Younger and older adults showed eye movement evidence of incidental memory for temporal relations, but only younger adults showed eye movement evidence of incidental memory for spatial relations. Together, these findings point towards a hierarchical organisation of relational memory. The implications of these findings are discussed in the context of the neural mechanisms that may support such a hierarchical organisation of memory.

  6. Relations between the functions of autobiographical memory and psychological wellbeing.

    PubMed

    Waters, Theodore E A

    2014-01-01

    Researchers have proposed that autobiographical memory serves three basic functions in everyday life: self-definition, social connection, and directing behaviour (e.g., Bluck, Alea, Habermas, & Rubin, 2005). However, no research has examined relations between the functions of autobiographical memory and healthy functioning (i.e., psychological wellbeing). The present research examined the relations between the self, social, and directive functions of autobiographical memory and three factors of psychological wellbeing in single and recurring autobiographical memories. A total of 103 undergraduate students were recruited and provided ratings of each function for four autobiographical memories (two single, two recurring events). Results found that individuals who use their autobiographical memories to serve self, social, and directive functions reported higher levels of Purpose and Communion and Positive Relationships, and that these relations differ slightly by event type.

  7. Comparative study of CNT, silicon nanowire and fullerene embedded multilayer high-k gate dielectric MOS memory devices

    NASA Astrophysics Data System (ADS)

    Sengupta, Amretashis; Sarkar, Chandan Kumar; Requejo, Felix G.

    2011-10-01

    Here, we present a comparative theoretical study on stacked (multilayer) gate dielectric MOS memory devices, having a metallic/semiconducting carbon nanotube (CNT), silicon nanowire (Si NW) and fullerene (C60) embedded nitride layer acting as a floating gate. Two types of devices, one with HfO2-SiO2 stack (stack-1) and the other with La2O3-SiO2 stack (stack-2) as the tunnel oxide were compared. We evaluated the effective barrier height, the dielectric constant and the effective electron mobility in the composite gate dielectric with the Maxwell-Garnett effective medium theory. Thereafter applying the WKB approximation, we simulated the Fowler-Nordheim (F-N) tunnelling/writing current and the direct tunnelling/leakage current in these devices. We evaluated the I-V characteristics, the charge decay and also the impact of CNT/Si NW aspect ratio and the volume fraction on the effective barrier height and the write voltage, respectively. We also simulated the write time, retention time and the erase time of these MOS devices. Based on the simulation results, it was concluded that the metallic CNT embedded stack-1 device offered the best performance in terms of higher F-N tunnelling current, lower direct tunnelling current and lesser write voltage and write time compared with the other devices. In case of direct tunnelling leakage and retention time it was found that the met CNT embedded stack-2 device showed better characteristics. For erasing, however, the C60 embedded stack-1 device showed the smallest erase time. When compared with earlier reports, it was seen that CNT, C60 and Si NW embedded devices all performed better than nanocrystalline Si embedded MOS non-volatile memories.

  8. Non-Alzheimer's disease-related memory impairment and dementia.

    PubMed

    Arlt, Sönke

    2013-12-01

    Although Alzheimer's disease (AD) is a common cause of memory impairment and dementia in the elderly disturbed memory function is a widespread subjective and/or objective symptom in a variety of medical conditions. The early detection and correct distinction of AD from non-AD memory impairment is critically important to detect possibly treatable and reversible underlying causes. In the context of clinical research, it is crucial to correctly distinguish between AD or non-AD memory impairment in order to build homogenous study populations for the assessment of new therapeutic possibilities. The distinction of AD from non-AD memory impairment may be difficult, especially in mildly affected patients, due to an overlap of clinical symptoms and biomarker alterations between AD and certain non-AD conditions. This review aims to describe recent aspects of the differential diagnosis of AD and non-AD related memory impairment and how these may be considered in the presence of memory deficits.

  9. Performance and retention characteristics of nanocrystalline Si floating gate memory with an Al2O3 tunnel layer fabricated by plasma-enhanced atomic layer deposition

    NASA Astrophysics Data System (ADS)

    Ma, Zhongyuan; Wang, Wen; Yang, Huafeng; Jiang, Xiaofan; Yu, Jie; Qin, Hua; Xu, Ling; Chen, Kunji; Huang, Xinfan; Li, Wei; Xu, Jun; Feng, Duan

    2016-02-01

    The down-scaling of nanocrystal Si (nc-Si) floating gate memory must overcome the challenge of leakage current induced by the conventional ultra-thin tunnel layer. We demonstrate that an improved memory performance based on the Al/SiNx/nc-Si/Al2O3/Si structure can be achieved by adopting the Al2O3 tunnel layer fabricated by plasma-enhanced atomic layer deposition. A larger memory window of 7.9 V and better retention characteristics of 4.7 V after 105 s can be obtained compared with the devices containing a conventional SiO2 tunnel layer of equivalent thickness. The capacitance-voltage characteristic reveals that the Al2O3 tunnel layer has a smaller electron barrier height, which ensures that more electrons are injected into the nc-Si dots through the Al2O3/Si interface. The analysis of the conductance-voltage and high-resolution cross-section transmission microscopy reveals that the smaller nc-Si dots dominate in the charge injection in the nc-Si floating gate MOS device with an Al2O3 tunnel layer. With an increase of the nc-Si size, both nc-Si and the interface contribute to the charge storage capacity and retention. The introduction of the Al2O3 tunnel layer in nc-Si floating gate memory provides a method to achieve an improved performance of nc-Si floating gate memory.

  10. Course of Relational and Non-Relational Recognition Memory across the Adult Lifespan

    ERIC Educational Resources Information Center

    Soei, Eleonore; Daum, Irene

    2008-01-01

    Human recognition memory shows a decline during normal ageing, which is thought to be related to age-associated dysfunctions of mediotemporal lobe structures. Whether the hippocampus is critical for human general relational memory or for spatial relational memory only is still disputed. The human perirhinal cortex is thought to be critically…

  11. Voltage-gated sodium channels: biophysics, pharmacology, and related channelopathies.

    PubMed

    Savio-Galimberti, Eleonora; Gollob, Michael H; Darbar, Dawood

    2012-01-01

    Voltage-gated sodium channels (VGSC) are multi-molecular protein complexes expressed in both excitable and non-excitable cells. They are primarily formed by a pore-forming multi-spanning integral membrane glycoprotein (α-subunit) that can be associated with one or more regulatory β-subunits. The latter are single-span integral membrane proteins that modulate the sodium current (I(Na)) and can also function as cell adhesion molecules. In vitro some of the cell-adhesive functions of the β-subunits may play important physiological roles independently of the α-subunits. Other endogenous regulatory proteins named "channel partners" or "channel interacting proteins" (ChiPs) like caveolin-3 and calmodulin/calmodulin kinase II (CaMKII) can also interact and modulate the expression and/or function of VGSC. In addition to their physiological roles in cell excitability and cell adhesion, VGSC are the site of action of toxins (like tetrodotoxin and saxitoxin), and pharmacologic agents (like antiarrhythmic drugs, local anesthetics, antiepileptic drugs, and newly developed analgesics). Mutations in genes that encode α- and/or β-subunits as well as the ChiPs can affect the structure and biophysical properties of VGSC, leading to the development of diseases termed sodium "channelopathies".  This review will outline the structure, function, and biophysical properties of VGSC as well as their pharmacology and associated channelopathies and highlight some of the recent advances in this field.

  12. Two-dimensional molybdenum disulphide nanosheet-covered metal nanoparticle array as a floating gate in multi-functional flash memories

    NASA Astrophysics Data System (ADS)

    Han, Su-Ting; Zhou, Ye; Chen, Bo; Zhou, Li; Yan, Yan; Zhang, Hua; Roy, V. A. L.

    2015-10-01

    Semiconducting two-dimensional materials appear to be excellent candidates for non-volatile memory applications. However, the limited controllability of charge trapping behaviors and the lack of multi-bit storage studies in two-dimensional based memory devices require further improvement for realistic applications. Here, we report a flash memory consisting of metal NPs-molybdenum disulphide (MoS2) as a floating gate by introducing a metal nanoparticle (NP) (Ag, Au, Pt) monolayer underneath the MoS2 nanosheets. Controlled charge trapping and long data retention have been achieved in a metal (Ag, Au, Pt) NPs-MoS2 floating gate flash memory. This controlled charge trapping is hypothesized to be attributed to band bending and a built-in electric field ξbi between the interface of the metal NPs and MoS2. The metal NPs-MoS2 floating gate flash memories were further proven to be multi-bit memory storage devices possessing a 3-bit storage capability and a good retention capability up to 104 s. We anticipate that these findings would provide scientific insight for the development of novel memory devices utilizing an atomically thin two-dimensional lattice structure.Semiconducting two-dimensional materials appear to be excellent candidates for non-volatile memory applications. However, the limited controllability of charge trapping behaviors and the lack of multi-bit storage studies in two-dimensional based memory devices require further improvement for realistic applications. Here, we report a flash memory consisting of metal NPs-molybdenum disulphide (MoS2) as a floating gate by introducing a metal nanoparticle (NP) (Ag, Au, Pt) monolayer underneath the MoS2 nanosheets. Controlled charge trapping and long data retention have been achieved in a metal (Ag, Au, Pt) NPs-MoS2 floating gate flash memory. This controlled charge trapping is hypothesized to be attributed to band bending and a built-in electric field ξbi between the interface of the metal NPs and MoS2. The metal

  13. A 2-bit/Cell Gate-All-Around Flash Memory of Self-Assembled Silicon Nanocrystals

    NASA Astrophysics Data System (ADS)

    Chen, Hung-Bin; Chang, Chun-Yen; Hung, Min-Feng; Tang, Zih-Yun; Cheng, Ya-Chi; Wu, Yung-Chun

    2013-02-01

    This work presents gate-all-around (GAA) polycrystalline silicon (poly-Si) nanowires (NWs) channel poly-Si/SiO2/Si3N4/SiO2/poly-Si (SONOS) nonvolatile memory (NVM) with a self-assembled Si nanocrystal (Si-NC) embedded charge trapping (CT) layer. Fabrication of the Si-NCs is simple and compatible with the current flash process. The 2-bit operations based on channel hot electrons injection for programming and channel hot holes injection for erasing are clearly achieved by the localized discrete trap. In the programming and erasing characteristics studies, the GAA structure can effectively reduce operation voltage and shorten pulse time. One-bit programming or erasing does not affect the other bit. In the high-temperature retention characteristics studies, the cell embedded with Si-NCs shows excellent electrons confinement vertically and laterally. With respect to endurance characteristics, the memory window does not undergo closure after 104 program/erase (P/E) cycle stress. The 2-bit operation for GAA Si-NCs NVM provides scalability, reliability and flexibility in three-dimensional (3D) high-density flash memory applications.

  14. Distributed Learning Enhances Relational Memory Consolidation

    ERIC Educational Resources Information Center

    Litman, Leib; Davachi, Lila

    2008-01-01

    It has long been known that distributed learning (DL) provides a mnemonic advantage over massed learning (ML). However, the underlying mechanisms that drive this robust mnemonic effect remain largely unknown. In two experiments, we show that DL across a 24 hr interval does not enhance immediate memory performance but instead slows the rate of…

  15. Floating-gated memory based on carbon nanotube field-effect transistors with Si floating dots

    NASA Astrophysics Data System (ADS)

    Seike, Kohei; Fujii, Yusuke; Ohno, Yasuhide; Maehashi, Kenzo; Inoue, Koichi; Matsumoto, Kazuhiko

    2014-01-01

    We have fabricated a carbon nanotube field-effect transistor (CNTFET)-based nonvolatile memory device with Si floating dots. The electrical characteristics of this memory device were compared with those of devices with a HfO2 charge storage layer or Au floating dots. For a sweep width of 6 V, the memory window of the devices with the Si floating dots increased twofold as compared with that of the devices with the HfO2 layer. Moreover, the retention characteristics revealed that, for the device with the Au floating dots, the off-state had almost the same current as the on-state at the 400th s. However, the devices with the Si floating dots had longer-retention characteristics. The results indicate that CNTFET-based devices with Si floating dots are promising candidates for low-power consumption nonvolatile memory devices.

  16. Investigation of impact of post-metallization annealing on reliability of 65 nm NOR floating-gate flash memories

    NASA Astrophysics Data System (ADS)

    Chiu, Shengfen; Xu, Yue; Ji, Xiaoli; Yan, Feng

    2016-12-01

    This paper investigates the impact of post-metallization annealing (PMA) in pure nitrogen ambient on the reliability of 65 nm NOR-type floating-gate flash memory devices. The experimental results show that, with PMA process, the cycling performance of flash cells, especially for the erasing speed is obviously degraded compared to that without PMA. It is found that the bulk oxide traps and tunnel oxide/Si interface traps are significantly increased with PMA treatment. The water/moisture residues left in the interlayer dielectric layers diffuse to tunnel oxide during PMA process is considered to be responsible for these traps generation, which further enhances the degradation of erase performance. Skipping PMA treatment is proposed to suppress the water diffusion effect on erase performance degradation of flash cells.

  17. Memory-related brain lateralisation in birds and humans.

    PubMed

    Moorman, Sanne; Nicol, Alister U

    2015-03-01

    Visual imprinting in chicks and song learning in songbirds are prominent model systems for the study of the neural mechanisms of memory. In both systems, neural lateralisation has been found to be involved in memory formation. Although many processes in the human brain are lateralised--spatial memory and musical processing involves mostly right hemisphere dominance, whilst language is mostly left hemisphere dominant--it is unclear what the function of lateralisation is. It might enhance brain capacity, make processing more efficient, or prevent occurrence of conflicting signals. In both avian paradigms we find memory-related lateralisation. We will discuss avian lateralisation findings and propose that birds provide a strong model for studying neural mechanisms of memory-related lateralisation.

  18. Sleep-related memory consolidation in primary insomnia.

    PubMed

    Nissen, Christoph; Kloepfer, Corinna; Feige, Bernd; Piosczyk, Hannah; Spiegelhalder, Kai; Voderholzer, Ulrich; Riemann, Dieter

    2011-03-01

    It has been suggested that healthy sleep facilitates the consolidation of newly acquired memories and underlying brain plasticity. The authors tested the hypothesis that patients with primary insomnia (PI) would show deficits in sleep-related memory consolidation compared to good sleeper controls (GSC). The study used a four-group parallel design (n=86) to investigate the effects of 12 h of night-time, including polysomnographically monitored sleep ('sleep condition' in PI and GSC), versus 12 h of daytime wakefulness ('wake condition' in PI and GSC) on procedural (mirror tracing task) and declarative memory consolidation (visual and verbal learning task). Demographic characteristics and memory encoding did not differ between the groups at baseline. Polysomnography revealed a significantly disturbed sleep profile in PI compared to GSC in the sleep condition. Night-time periods including sleep in GSC were associated with (i) a significantly enhanced procedural and declarative verbal memory consolidation compared to equal periods of daytime wakefulness in GSC and (ii) a significantly enhanced procedural memory consolidation compared to equal periods of daytime wakefulness and night-time sleep in PI. Across retention intervals of daytime wakefulness, no differences between the experimental groups were observed. This pattern of results suggests that healthy sleep fosters the consolidation of new memories, and that this process is impaired for procedural memories in patients with PI. Future work is needed to investigate the impact of treatment on improving sleep and memory.

  19. Formation of holographic memory for optically reconfigurable gate array by angle-multiplexing recording of multi-circuit information in liquid crystal composites

    NASA Astrophysics Data System (ADS)

    Ogiwara, Akifumi; Maekawa, Hikaru; Watanabe, Minoru; Moriwaki, Retsu

    2014-02-01

    A holographic polymer-dispersed liquid crystal (HPDLC) memory to record multi-context information for an optically reconfigurable gate array is formed by the angle-multiplexing recording using a successive laser exposure in liquid crystal (LC) composites. The laser illumination system is constructed using the half mirror and photomask written by the different configuration contexts placed on the motorized stages under the control of a personal computer. The fabricated holographic memory implements a precise reconstruction of configuration contexts corresponding to the various logical circuits such as OR circuit and NOR circuit by the laser illumination at different incident angle in the HPDLC memory.

  20. The ontogeny of relational memory and pattern separation.

    PubMed

    Ngo, Chi T; Newcombe, Nora S; Olson, Ingrid R

    2017-03-02

    Episodic memory relies on memory for the relations among multiple elements of an event and the ability to discriminate among similar elements of episodes. The latter phenomenon, termed pattern separation, has been studied mainly in young and older adults with relatively little research on children. Building on prior work with young children, we created an engaging computer-administered relational memory task assessing what-where relations. We also modified the Mnemonic Similarity Task used to assess pattern discrimination in young and older adults for use with preschool children. Results showed that 4-year-olds performed significantly worse than 6-year-olds and adults on both tasks, whereas 6-year-olds and adults performed comparably, even though there were no ceiling effects. However, performance on the two tasks did not correlate, suggesting that two distinct mnemonic processes with different developmental trajectories may contribute to age-related changes in episodic memory.

  1. Analysis of Si-SiO2 Interface Using Charge Pumping Method with Various Capping Materials between Gate Stacks and Inter Layer Dielectric in NAND Flash Memory

    NASA Astrophysics Data System (ADS)

    Kim, Nam-Kyeong; Kim, Se-Jun; Park, Kyoung-Hwan; Choi, Eun-Seok; Lee, Min-Kyu; Kim, Hyeon-Soo; Noh, Keum-Hwan; Om, Jae-Chul; Lee, Hee-Kee; Bae, Gi-Hyun

    2006-09-01

    We report the dependence of Si-SiO2 interface trap density after Fowler-Nordheim (F/N) stress on various capping materials between gate stacks and an inter layer dielectric (ILD) in a NAND Flash memory cell. The interface trap density was characterized by charge pumping method (CPM). When the capping layer is an oxide, the Nit after F/N stress is approximately 2× 1011 cm-2, which is about 50% smaller than that with a nitride layer. We found that the oxide layer causes compressive stress whereas the nitride layer causes a relatively high tensile stress in the underlying substrate by measuring the warp change of the substrate. To correlate the interface state density and data retention characteristics, we measured Vt shift after high-temperature baking. When an oxide capping layer is used, the retention characteristics of memory devices are greatly improved compared to the nitride capping case. These results show a good correlation between the interface characteristics and mechanical stress behaviors.

  2. Hf-based high-k materials for Si nanocrystal floating gate memories

    PubMed Central

    2011-01-01

    Pure and Si-rich HfO2 layers fabricated by radio frequency sputtering were utilized as alternative tunnel oxide layers for high-k/Si-nanocrystals-SiO2/SiO2 memory structures. The effect of Si incorporation on the properties of Hf-based tunnel layer was investigated. The Si-rich SiO2 active layers were used as charge storage layers, and their properties were studied versus deposition conditions and annealing treatment. The capacitance-voltage measurements were performed to study the charge trapping characteristics of these structures. It was shown that with specific deposition conditions and annealing treatment, a large memory window of about 6.8 V is achievable at a sweeping voltage of ± 6 V, indicating the utility of these stack structures for low-operating-voltage nonvolatile memory devices. PMID:21711676

  3. Self-images and related autobiographical memories in schizophrenia.

    PubMed

    Bennouna-Greene, Mehdi; Berna, Fabrice; Conway, Martin A; Rathbone, Clare J; Vidailhet, Pierre; Danion, Jean-Marie

    2012-03-01

    Schizophrenia is a severe mental illness, which affects sense of identity. While the ability to have a coherent vision of the self (i.e., self-images) relies partly on its reciprocal relationships with autobiographical memories, little is known about how memories ground "self-images" in schizophrenia. Twenty-five patients with schizophrenia and 25 controls were asked to give six autobiographical memories related to four self-statements they considered essential for defining their identity. Results showed that patients' self-images were more passive than those of controls. Autobiographical memories underlying self-images were less thematically linked to these self-images in patients. We also found evidence of a weakened sense of self and a deficient organization of autobiographical memories grounding the self in schizophrenia. These abnormalities may account for the poor cohesiveness of the self in schizophrenia.

  4. Selective sexual orientation-related differences in object location memory.

    PubMed

    Hassan, Bano; Rahman, Qazi

    2007-06-01

    The present study examined sexual orientation-related differences in object location memory by using 3 object arrays (testing object exchange, object shift, and novel objects conditions) and 1 metric positional memory array. Heterosexual women and homosexual men significantly outperformed heterosexual men in all 3 object arrays. However, there were no group differences in metric positional memory. Heterosexual males expectedly outperformed the other groups in spatial perception (Judgment of Line Orientation; A. L. Benton, K. D. Hamsher, N. R. Varney, & O. Spreen, 1983). Regression modeling revealed that sexual orientation and spatial perception predicted object exchange performance, whereas recalled childhood gender nonconformity, a robust developmental marker of adult sexual orientation, predicted object shift and novel object performance alone. A measure ascribed to the actions of prenatal androgens, the 2nd to 4th finger length ratio, did not predict object location memory. These data may limit possible developmental pathways for sexual variation in selective forms of spatial memory.

  5. Floating gate memory with charge storage dots array formed by Dps protein modified with site-specific binding peptides

    NASA Astrophysics Data System (ADS)

    Kamitake, Hiroki; Uenuma, Mutsunori; Okamoto, Naofumi; Horita, Masahiro; Ishikawa, Yasuaki; Yamashita, Ichro; Uraoka, Yukiharu

    2015-05-01

    We report a nanodot (ND) floating gate memory (NFGM) with a high-density ND array formed by a biological nano process. We utilized two kinds of cage-shaped proteins displaying SiO2 binding peptide (minTBP-1) on their outer surfaces: ferritin and Dps, which accommodate cobalt oxide NDs in their cavities. The diameters of the cobalt NDs were regulated by the cavity sizes of the proteins. Because minTBP-1 is strongly adsorbed on the SiO2 surface, high-density cobalt oxide ND arrays were obtained by a simple spin coating process. The densities of cobalt oxide ND arrays based on ferritin and Dps were 6.8 × 1011 dots cm-2 and 1.2 × 1012 dots cm-2, respectively. After selective protein elimination and embedding in a metal-oxide-semiconductor (MOS) capacitor, the charge capacities of both ND arrays were evaluated by measuring their C-V characteristics. The MOS capacitor embedded with the Dps ND array showed a wider memory window than the device embedded with the ferritin ND array. Finally, we fabricated an NFGM with a high-density ND array based on Dps, and confirmed its competent writing/erasing characteristics and long retention time.

  6. Memory deficit in patients with schizophrenia and posttraumatic stress disorder: relational vs item-specific memory

    PubMed Central

    Jung, Wookyoung; Lee, Seung-Hwan

    2016-01-01

    It has been well established that patients with schizophrenia have impairments in cognitive functioning and also that patients who experienced traumatic events suffer from cognitive deficits. Of the cognitive deficits revealed in schizophrenia or posttraumatic stress disorder (PTSD) patients, the current article provides a brief review of deficit in episodic memory, which is highly predictive of patients’ quality of life and global functioning. In particular, we have focused on studies that compared relational and item-specific memory performance in schizophrenia and PTSD, because measures of relational and item-specific memory are considered the most promising constructs for immediate tangible development of clinical trial paradigm. The behavioral findings of schizophrenia are based on the tasks developed by the Cognitive Neuroscience Treatment Research to Improve Cognition in Schizophrenia (CNTRICS) initiative and the Cognitive Neuroscience Test Reliability and Clinical Applications for Schizophrenia (CNTRACS) Consortium. The findings we reviewed consistently showed that schizophrenia and PTSD are closely associated with more severe impairments in relational memory compared to item-specific memory. Candidate brain regions involved in relational memory impairment in schizophrenia and PTSD are also discussed. PMID:27274250

  7. Aerobic fitness predicts relational memory but not item memory performance in healthy young adults.

    PubMed

    Baym, Carol L; Khan, Naiman A; Pence, Ari; Raine, Lauren B; Hillman, Charles H; Cohen, Neal J

    2014-11-01

    Health factors such as an active lifestyle and aerobic fitness have long been linked to decreased risk of cardiovascular disease, stroke, and other adverse health outcomes. Only more recently have researchers begun to investigate the relationship between aerobic fitness and memory function. Based on recent findings in behavioral and cognitive neuroscience showing that the hippocampus might be especially sensitive to the effects of exercise and fitness, the current study assessed hippocampal-dependent relational memory and non-hippocampal-dependent item memory in young adults across a range of aerobic fitness levels. Aerobic fitness was assessed using a graded exercise test to measure oxygen consumption during maximal exercise (VO2max), and relational and item memory were assessed using behavioral and eye movement measures. Behavioral results indicated that aerobic fitness was positively correlated with relational memory performance but not item memory performance, suggesting that the beneficial effects of aerobic fitness selectively affect hippocampal function and not that of the surrounding medial temporal lobe cortex. Eye movement results further supported the specificity of this fitness effect to hippocampal function, in that aerobic fitness predicted disproportionate preferential viewing of previously studied relational associations but not of previously viewed items. Potential mechanisms underlying this pattern of results, including neurogenesis, are discussed.

  8. Taking electrons out of bioelectronics: bioprotonic memories and enzymatic logic gates (Presentation Recording)

    NASA Astrophysics Data System (ADS)

    Rolandi, Marco

    2015-10-01

    In living systems, protonic and ionic currents are the basis for all information processing. As such, artificial devices based on protonic and ionic currents offer an exciting opportunity for bioelectronics. Proton transport in nature is important for ATP oxidative phosphorylation, the HCVN1 voltage gated proton channel, light activated proton pumping in bacteriorhodopsin, and the proton conducting single water file of the antibiotic gramicidin. In these systems, protons move along hydrogen bond networks formed by water and the hydrated biomolecules (proton wires). We have previously demonstrated complementary H+- and OH-- FETs with acid and base doped biopolymer proton wires and PdHx proton conducting contacts. Here, I will discuss proton-conducting devices based oh highly conductive proton wires that emulate brain synapses, display memristive behaviour, and are connected to form shift registries. Furthermore, I will present the integration of these devices with enzymatic logic gates for integrated biotic-abiotic protonic information processing. Preliminary results on using these devices to affect biological function will be discussed.

  9. Aerobic fitness, hippocampal viscoelasticity, and relational memory performance.

    PubMed

    Schwarb, Hillary; Johnson, Curtis L; Daugherty, Ana M; Hillman, Charles H; Kramer, Arthur F; Cohen, Neal J; Barbey, Aron K

    2017-03-30

    The positive relationship between hippocampal structure, aerobic fitness, and memory performance is often observed among children and older adults; but evidence of this relationship among young adults, for whom the hippocampus is neither developing nor atrophying, is less consistent. Studies have typically relied on hippocampal volumetry (a gross proxy of tissue composition) to assess individual differences in hippocampal structure. While volume is not specific to microstructural tissue characteristics, microstructural differences in hippocampal integrity may exist even among healthy young adults when volumetric differences are not diagnostic of tissue health or cognitive function. Magnetic resonance elastography (MRE) is an emerging noninvasive imaging technique for measuring viscoelastic tissue properties and provides quantitative measures of tissue integrity. We have previously demonstrated that individual differences in hippocampal viscoelasticity are related to performance on a relational memory task; however, little is known about health correlates to this novel measure. In the current study, we investigated the relationship between hippocampal viscoelasticity and cardiovascular health, and their mutual effect on relational memory in a group of healthy young adults (N=51). We replicated our previous finding that hippocampal viscoelasticity correlates with relational memory performance. We extend this work by demonstrating that better aerobic fitness, as measured by VO2max, was associated with hippocampal viscoelasticity that mediated the benefits of fitness on memory function. Hippocampal volume, however, did not account for individual differences in memory. Therefore, these data suggest that hippocampal viscoelasticity may provide a more sensitive measure to microstructural tissue organization and its consequences to cognition among healthy young adults.

  10. Experimental realization of programmable quantum gate array for directly probing commutation relations of Pauli operators.

    PubMed

    Yao, Xing-Can; Fiurásek, Jaromír; Lu, He; Gao, Wei-Bo; Chen, Yu-Ao; Chen, Zeng-Bing; Pan, Jian-Wei

    2010-09-17

    We experimentally demonstrate an advanced linear-optical programmable quantum processor that combines two elementary single-qubit programmable quantum gates. We show that this scheme enables direct experimental probing of quantum commutation relations for Pauli operators acting on polarization states of single photons. Depending on a state of two-qubit program register, we can probe either commutation or anticommutation relations. Very good agreement between theory and experiment is observed, indicating high-quality performance of the implemented quantum processor.

  11. Uncertainty relations based on skew information with quantum memory

    NASA Astrophysics Data System (ADS)

    Ma, ZhiHao; Chen, ZhiHua; Fei, Shao-Ming

    2017-01-01

    We present a new uncertainty relation by defining a measure of uncertainty based on skew information. For bipartite systems, we establish uncertainty relations with the existence of a quantum memory. A general relation between quantum correlations and tight bounds of uncertainty has been presented.

  12. Channel shape and interpoly dielectric material effects on electrical characteristics of floating-gate-type three-dimensional fin channel flash memories

    NASA Astrophysics Data System (ADS)

    Liu, Yongxun; Nabatame, Toshihide; Nguyen, Num; Matsukawa, Takashi; Endo, Kazuhiko; O'uchi, Shinichi; Tsukada, Junichi; Yamauchi, Hiromi; Ishikawa, Yuki; Mizubayashi, Wataru; Morita, Yukinori; Migita, Shinji; Ota, Hiroyuki; Chikyow, Toyohiro; Masahara, Meishoku

    2015-04-01

    Floating-gate (FG)-type three-dimensional (3D) fin channel flash memories with triangular fin (TF) and rectangular fin (RF) channels and different interpoly dielectric (IPD) materials have been successfully fabricated using (100)- and (110)-oriented silicon-on-insulator (SOI) wafers and orientation-dependent wet etching. The electrical characteristics of the fabricated FG-type 3D fin channel flash memories including threshold voltage (Vt) variability, program/erase (P/E) speed, memory window, endurance, and data retention at room temperature and 85 °C have been comparatively investigated. A higher P/E speed, a larger memory window, and a lower-voltage operation are experimentally obtained in the TF channel flash memories with an Al2O3-nitride-oxide (ANO) IPD layer (TF-ANO) than in the RF channel ones with the same ANO IPD layer (RF-ANO) and the TF channel ones with an oxide-nitride-oxide (ONO) IPD layer (TF-ONO). The larger memory window and lower-voltage operation of TF-ANO flash memories are due to the high-k effect of the Al2O3 layer and the electric field enhancement at the sharp foot edges of the TF channels. It was also found that data retention for all fabricated FG-type 3D fin channel flash memories shows a weak dependence on temperature.

  13. Assessment of Motor Function, Sensory Motor Gating and Recognition Memory in a Novel BACHD Transgenic Rat Model for Huntington Disease

    PubMed Central

    Abada, Yah-se K.; Nguyen, Huu Phuc; Schreiber, Rudy; Ellenbroek, Bart

    2013-01-01

    Rationale Huntington disease (HD) is frequently first diagnosed by the appearance of motor symptoms; the diagnosis is subsequently confirmed by the presence of expanded CAG repeats (> 35) in the HUNTINGTIN (HTT) gene. A BACHD rat model for HD carrying the human full length mutated HTT with 97 CAG-CAA repeats has been established recently. Behavioral phenotyping of BACHD rats will help to determine the validity of this model and its potential use in preclinical drug discovery studies. Objectives The present study seeks to characterize the progressive emergence of motor, sensorimotor and cognitive deficits in BACHD rats. Materials and Methods Wild type and transgenic rats were tested from 1 till 12 months of age. Motor tests were selected to measure spontaneous locomotor activity (open field) and gait coordination. Sensorimotor gating was assessed in acoustic startle response paradigms and recognition memory was evaluated in an object recognition test. Results Transgenic rats showed hyperactivity at 1 month and hypoactivity starting at 4 months of age. Motor coordination imbalance in a Rotarod test was present at 2 months and gait abnormalities were seen in a Catwalk test at 12 months. Subtle sensorimotor changes were observed, whereas object recognition was unimpaired in BACHD rats up to 12 months of age. Conclusion The current BACHD rat model recapitulates certain symptoms from HD patients, especially the marked motor deficits. A subtle neuropsychological phenotype was found and further studies are needed to fully address the sensorimotor phenotype and the potential use of BACHD rats for drug discovery purposes. PMID:23874679

  14. Pupillary responses and memory-guided visual search reveal age-related and Alzheimer's-related memory decline.

    PubMed

    Dragan, Michelle C; Leonard, Timothy K; Lozano, Andres M; McAndrews, Mary Pat; Ng, Karen; Ryan, Jennifer D; Tang-Wai, David F; Wynn, Jordana S; Hoffman, Kari L

    2017-03-30

    Episodic memory - composed of memory for unique spatiotemporal experiences - is known to decline with aging, and even more severely in Alzheimer 's disease (AD). Memory for trial-unique objects in spatial scenes depends on the integrity of the hippocampus and interconnected structures that are among the first areas affected in AD. We reasoned that memory for objects-in-scenes would be impaired with aging, and that further impairments would be observed in AD. We asked younger adults, healthy older adults, older adults at-risk for developing cognitive impairments, and older adults with probable early AD to find changing items ('targets') within images of natural scenes, measuring repeated-trial changes in search efficiency and pupil diameter. Compared to younger adults, older adults took longer to detect target objects in repeated scenes, they required more fixations and those fixations were more dispersed. Whereas individuals with AD showed some benefit of memory in this task, they had substantially longer detection times, and more numerous, dispersed fixations on repeated scenes compared to age-matched older adults. Correspondingly, pupillary responses to novel and repeated scenes were diminished with aging and further in AD, and the memory-related changes were weaker with aging and absent in AD. Our results suggest that several nonverbal measures from memory-guided visual search tasks can index aging and Alzheimer's disease status, including pupillary dynamics. The task measurements are sensitive to the integrity of brain structures that are associated with Alzheimer's-related neurodegeneration, the task is well tolerated across a range of abilities, and thus, it may prove useful in early diagnostics and longitudinal tracking of memory decline.

  15. Glial dysfunction causes age-related memory impairment in Drosophila.

    PubMed

    Yamazaki, Daisuke; Horiuchi, Junjiro; Ueno, Kohei; Ueno, Taro; Saeki, Shinjiro; Matsuno, Motomi; Naganos, Shintaro; Miyashita, Tomoyuki; Hirano, Yukinori; Nishikawa, Hiroyuki; Taoka, Masato; Yamauchi, Yoshio; Isobe, Toshiaki; Honda, Yoshiko; Kodama, Tohru; Masuda, Tomoko; Saitoe, Minoru

    2014-11-19

    Several aging phenotypes, including age-related memory impairment (AMI), are thought to be caused by cumulative oxidative damage. In Drosophila, age-related impairments in 1 hr memory can be suppressed by reducing activity of protein kinase A (PKA). However, the mechanism for this effect has been unclear. Here we show that decreasing PKA suppresses AMI by reducing activity of pyruvate carboxylase (PC), a glial metabolic enzyme whose amounts increase upon aging. Increased PC activity causes AMI through a mechanism independent of oxidative damage. Instead, increased PC activity is associated with decreases in D-serine, a glia-derived neuromodulator that regulates NMDA receptor activity. D-serine feeding suppresses both AMI and memory impairment caused by glial overexpression of dPC, indicating that an oxidative stress-independent dysregulation of glial modulation of neuronal activity contributes to AMI in Drosophila.

  16. Nonvolatile Multilevel Memory and Boolean Logic Gates Based on a Single Ni /[Pb (Mg1 /3Nb2 /3)O3]0.7[PbTiO3]0.3/Ni Heterostructure

    NASA Astrophysics Data System (ADS)

    Shen, Jianxin; Shang, Dashan; Chai, Yisheng; Wang, Yue; Cong, Junzhuang; Shen, Shipeng; Yan, Liqin; Wang, Wenhong; Sun, Young

    2016-12-01

    Memtranstor that correlates charge and magnetic flux via nonlinear magnetoelectric effects has a great potential in developing next-generation nonvolatile devices. In addition to multilevel nonvolatile memory, we demonstrate here that nonvolatile logic gates such as nor and nand can be implemented in a single memtranstor made of the Ni /PMN -PT /Ni heterostructure. After applying two sequent voltage pulses (X1 , X2 ) as the logic inputs on the memtranstor, the output magnetoelectric voltage can be positive high (logic 1), positive low (logic 0), or negative (logic 0), depending on the levels of X1 and X2 . The underlying physical mechanism is related to the complete or partial reversal of ferroelectric polarization controlled by inputting selective voltage pulses, which determines the magnitude and sign of the magnetoelectric voltage coefficient. The combined functions of both memory and logic could enable the memtranstor as a promising candidate for future computing systems beyond von Neumann architecture.

  17. Life Experience with Death: Relation to Death Attitudes and to the Use of Death-Related Memories

    ERIC Educational Resources Information Center

    Bluck, Susan; Dirk, Judith; Mackay, Michael M.; Hux, Ashley

    2008-01-01

    The study examines the relation of death experience to death attitudes and to autobiographical memory use. Participants (N = 52) completed standard death attitude measures and wrote narratives about a death-related autobiographical memory and (for comparison) a memory of a low point. Self-ratings of the memory narratives were used to assess their…

  18. The Relations Among Abuse, Depression, and Adolescents' Autobiographical Memory

    ERIC Educational Resources Information Center

    Johnson, Rebecca J.; Greenhoot, Andrea Follmer; Glisky, Elizabeth; McCloskey, Laura A.

    2005-01-01

    This study examined the relations among early and recent experiences with abuse, depression, and adolescents' autobiographical memory in a longitudinal study of family violence. Participants' (N = 134) exposure to violence was documented when they were 6 to 12 years old and again when they were 12 to 18 years old. The second assessment included…

  19. Working Memory and Intelligence Are Highly Related Constructs, but Why?

    ERIC Educational Resources Information Center

    Colom, Roberto; Abad, Francisco J.; Quiroga, M. Angeles; Shih, Pei Chun; Flores-Mendoza, Carmen

    2008-01-01

    Working memory and the general factor of intelligence (g) are highly related constructs. However, we still don't know why. Some models support the central role of simple short-term storage, whereas others appeal to executive functions like the control of attention. Nevertheless, the available empirical evidence does not suffice to get an answer,…

  20. Spatial Relational Memory in 9-Month-Old Macaque Monkeys

    ERIC Educational Resources Information Center

    Lavenex, Pierre; Lavenex, Pamela Banta

    2006-01-01

    This experiment assesses spatial and nonspatial relational memory in freely moving 9-mo-old and adult (11-13-yr-old) macaque monkeys ("Macaca mulatta"). We tested the use of proximal landmarks, two different objects placed at the center of an open-field arena, as conditional cues allowing monkeys to predict the location of food rewards hidden in…

  1. Improved uncertainty relation in the presence of quantum memory

    NASA Astrophysics Data System (ADS)

    Xiao, Yunlong; Jing, Naihuan; Fei, Shao-Ming; Li-Jost, Xianqing

    2016-12-01

    Berta et al’s uncertainty principle in the presence of quantum memory (Berta et al 2010 Nat. Phys. 6 659) reveals uncertainties with quantum side information between the observables. In the recent important work of Coles and Piani (2014 Phys. Rev. A 89 022112), the entropic sum is controlled by the first and second maximum overlaps between the two projective measurements. We generalize the entropic uncertainty relation in the presence of quantum memory and find the exact dependence on all d largest overlaps between two measurements on any d-dimensional Hilbert space. Our bound is rigorously shown to be strictly tighter than previous entropic bounds in the presence of quantum memory, which have potential applications to quantum cryptography with entanglement witnesses and quantum key distributions.

  2. Investigation of p-channel and n-channel junctionless gate-all-around polycrystalline silicon nanowires with silicon nanocrystals nonvolatile memory

    NASA Astrophysics Data System (ADS)

    Yeh, Mu-Shih; Wu, Yung-Chun; Chung, Ming-Hsien; Jhan, Yi-Ruei; Chang-Liao, Kuei-Shu; Liu, Kuan-Cheng; Wu, Min-Hsin; Hung, Min-Feng

    2014-07-01

    This work presents p-channel and n-channel junctionless (JL) polycrystalline silicon (poly-Si) nanowires gate-all-around (GAA) nonvolatile memory (NVM) devices with silicon nanocrystals charge trapping layer. Experimental results indicate that the n-channel device has better programming efficiency and p-channel device has better erasing efficiency. For p-channel device, an extrapolation of the memory window to 10 yr demonstrates that 95% of the stored charge can be retained at high temperature of 85 °C. Such the p-channel and n-channel JL-GAA NVMs are feasible for use in system-on-panel (SOP) and 3-D stacked flash memory applications.

  3. CEREBROVASCULAR DAMAGE MEDIATES RELATIONS BETWEEN AORTIC STIFFNESS AND MEMORY

    PubMed Central

    Cooper, Leroy L.; Woodard, Todd; Sigurdsson, Sigurdur; van Buchem, Mark A.; Torjesen, Alyssa A.; Inker, Lesley A.; Aspelund, Thor; Eiriksdottir, Gudny; Harris, Tamara B.; Gudnason, Vilmundur; Launer, Lenore J.; Mitchell, Gary F.

    2015-01-01

    Aortic stiffness is associated with cognitive decline. Here, we examined the association between carotid-femoral pulse wave velocity and cognitive function and investigated whether cerebrovascular remodeling and parenchymal small vessel disease damage mediate the relation. Analyses were based on 1820 (60% women) participants in the Age, Gene/Environment Susceptibility – Reykjavik Study. Multivariable linear regression models adjusted for vascular and demographic confounders showed that higher carotid-femoral pulse wave velocity was related to lower memory score (standardized β: −0.071±0.023; P=0.002). Cerebrovascular resistance and white matter hyperintensities were each associated with carotid-femoral pulse wave velocity and memory (P<0.05). Together, cerebrovascular resistance and white matter hyperintensities (total indirect effect: −0.029; 95% CI: −0.043, −0.017) attenuated the direct relation between carotid-femoral pulse wave velocity and memory (direct effect: −0.042; 95% CI: −0.087, 0.003; P=0.07) and explained approximately 41% of the observed effect. Our results suggest that in older adults, associations between aortic stiffness and memory are mediated by pathways that include cerebral microvascular remodeling and microvascular parenchymal damage. PMID:26573713

  4. Memory for Items and Relationships among Items Embedded in Realistic Scenes: Disproportionate Relational Memory Impairments in Amnesia

    PubMed Central

    Hannula, Deborah E.; Tranel, Daniel; Allen, John S.; Kirchhoff, Brenda A.; Nickel, Allison E.; Cohen, Neal J.

    2014-01-01

    Objective The objective of this study was to examine the dependence of item memory and relational memory on medial temporal lobe (MTL) structures. Patients with amnesia, who either had extensive MTL damage or damage that was relatively restricted to the hippocampus, were tested, as was a matched comparison group. Disproportionate relational memory impairments were predicted for both patient groups, and those with extensive MTL damage were also expected to have impaired item memory. Method Participants studied scenes, and were tested with interleaved two-alternative forced-choice probe trials. Probe trials were either presented immediately after the corresponding study trial (lag 1), five trials later (lag 5), or nine trials later (lag 9) and consisted of the studied scene along with a manipulated version of that scene in which one item was replaced with a different exemplar (item memory test) or was moved to a new location (relational memory test). Participants were to identify the exact match of the studied scene. Results As predicted, patients were disproportionately impaired on the test of relational memory. Item memory performance was marginally poorer among patients with extensive MTL damage, but both groups were impaired relative to matched comparison participants. Impaired performance was evident at all lags, including the shortest possible lag (lag 1). Conclusions The results are consistent with the proposed role of the hippocampus in relational memory binding and representation, even at short delays, and suggest that the hippocampus may also contribute to successful item memory when items are embedded in complex scenes. PMID:25068665

  5. Nonvolatile memory thin-film transistors using biodegradable chicken albumen gate insulator and oxide semiconductor channel on eco-friendly paper substrate.

    PubMed

    Kim, So-Jung; Jeon, Da-Bin; Park, Jung-Ho; Ryu, Min-Ki; Yang, Jong-Heon; Hwang, Chi-Sun; Kim, Gi-Heon; Yoon, Sung-Min

    2015-03-04

    Nonvolatile memory thin-film transistors (TFTs) fabricated on paper substrates were proposed as one of the eco-friendly electronic devices. The gate stack was composed of chicken albumen gate insulator and In-Ga-Zn-O semiconducting channel layers. All the fabrication processes were performed below 120 °C. To improve the process compatibility of the synthethic paper substrate, an Al2O3 thin film was introduced as adhesion and barrier layers by atomic layer deposition. The dielectric properties of biomaterial albumen gate insulator were also enhanced by the preparation of Al2O3 capping layer. The nonvolatile bistabilities were realized by the switching phenomena of residual polarization within the albumen thin film. The fabricated device exhibited a counterclockwise hysteresis with a memory window of 11.8 V, high on/off ratio of approximately 1.1 × 10(6), and high saturation mobility (μsat) of 11.5 cm(2)/(V s). Furthermore, these device characteristics were not markedly degraded even after the delamination and under the bending situration. When the curvature radius was set as 5.3 cm, the ION/IOFF ratio and μsat were obtained to be 5.9 × 10(6) and 7.9 cm(2)/(V s), respectively.

  6. Enhancement of programming speed on gate-all-around poly-silicon nanowire nonvolatile memory using self-aligned NiSi Schottky barrier source/drain

    NASA Astrophysics Data System (ADS)

    Ho, Ching-Yuan; Chang, Yaw-Jen; Chiou, Y. L.

    2013-08-01

    The programming characteristics of gate-all-around silicon-oxide-nitride-oxide silicon (SONOS) nonvolatile memories are presented using NiSi/poly-Si nanowires (SiNW) Schottky barrier (SB) heterojunctions. The non-uniform thermal stress distribution on SiNW channels due to joule heating affected the carrier transport behavior. Under a high drain voltage, impact ionization was found as a large lateral field enhances carrier velocity. As gate voltage (Vg) increased, the difference in the drain current within a range of various temperature conditions can be mitigated because a high gate field lowers the SB height of a NiSi source/SiNW/NiSi drain junction to ensure efficient hot-carrier generation. By applying the Fowler-Nordheim programming voltage to the SONOS nanowire memory, the SB height (Φn = 0.34 eV) could be reduced by image force; thus, hot electrons could be injected from SB source/drain electrodes into the SiN storage node. To compare both SiNW and Si nanocrystal SONOS devices, the SB SiNW SONOS device was characterized experimentally to propose a wider threshold-voltage window, exhibiting efficient programming characteristics.

  7. Medial Temporal Lobe Activity Predicts Successful Relational Memory Binding

    PubMed Central

    Hannula, Deborah E.; Ranganath, Charan

    2009-01-01

    Previous neuropsychological findings have implicated medial temporal lobe (MTL) structures in retaining object-location relations over the course of short delays, but MTL effects have not always been reported in neuroimaging investigations with similar short-term memory requirements. Here, we used event-related functional magnetic resonance imaging to test the hypothesis that the hippocampus and related MTL structures support accurate retention of relational memory representations, even across short delays. On every trial, four objects were presented, each in one of nine possible locations of a three-dimensional grid. Participants were to mentally rotate the grid and then maintain the rotated representation in anticipation of a test stimulus: a rendering of the grid, rotated 90° from the original viewpoint. The test stimulus was either a “match” display, in which object-location relations were intact, or a “mismatch” display, in which one object occupied a new, previously unfilled location (mismatch position), or two objects had swapped locations (mismatch swap). Encoding phase activation in anterior and posterior regions of the left hippocampus, and in bilateral perirhinal cortex, predicted subsequent accuracy on the short-term memory decision, as did bilateral posterior hippocampal activity after the test stimulus. Notably, activation in these posterior hippocampal regions was also sensitive to the degree to which object-location bindings were preserved in the test stimulus; activation was greatest for match displays, followed by mismatch-position displays, and finally mismatch-swap displays. These results indicate that the hippocampus and related MTL structures contribute to successful encoding and retrieval of relational information in visual short-term memory. PMID:18171929

  8. Dissociable Memory- and Response-Related Activity in Parietal Cortex During Auditory Spatial Working Memory

    PubMed Central

    Alain, Claude; Shen, Dawei; Yu, He; Grady, Cheryl

    2010-01-01

    Attending and responding to sound location generates increased activity in parietal cortex which may index auditory spatial working memory and/or goal-directed action. Here, we used an n-back task (Experiment 1) and an adaptation paradigm (Experiment 2) to distinguish memory-related activity from that associated with goal-directed action. In Experiment 1, participants indicated, in separate blocks of trials, whether the incoming stimulus was presented at the same location as in the previous trial (1-back) or two trials ago (2-back). Prior to a block of trials, participants were told to use their left or right index finger. Accuracy and reaction times were worse for the 2-back than for the 1-back condition. The analysis of functional magnetic resonance imaging data revealed greater sustained task-related activity in the inferior parietal lobule (IPL) and superior frontal sulcus during 2-back than 1-back after accounting for response-related activity elicited by the targets. Target detection and response execution were also associated with enhanced activity in the IPL bilaterally, though the activation was anterior to that associated with sustained task-related activity. In Experiment 2, we used an event-related design in which participants listened (no response required) to trials that comprised four sounds presented either at the same location or at four different locations. We found larger IPL activation for changes in sound location than for sounds presented at the same location. The IPL activation overlapped with that observed during the auditory spatial working memory task. Together, these results provide converging evidence supporting the role of parietal cortex in auditory spatial working memory which can be dissociated from response selection and execution. PMID:21833258

  9. When memory meets beauty: Insights from event-related potentials.

    PubMed

    Marzi, T; Viggiano, M P

    2010-05-01

    Facial attractiveness plays a key role in human social and affective behavior. To study the time course of the neural processing of attractiveness and its influence on recognition memory we investigated the event-related potentials (ERPs) elicited in an old/new recognition task in response to faces with a neutral expression that, at encoding, were rated for their attractiveness. Highly attractive faces elicited a specific early positive-going component on frontal sites; in addition, with respect to less attractive faces, they elicited larger later components related to structural encoding and recognition memory. All in all, our results show that facial attractiveness, independently from facial expression, modulates face processing throughout all stages from encoding to retrieval.

  10. Olfactory memory in the old and very old: relations to episodic and semantic memory and APOE genotype.

    PubMed

    Larsson, Maria; Hedner, Margareta; Papenberg, Goran; Seubert, Janina; Bäckman, Lars; Laukka, Erika J

    2016-02-01

    The neuroanatomical organization that underlies olfactory memory is different from that of other memory types. The present work examines olfactory memory in an elderly population-based sample (Swedish National Study on Aging and Care in Kungsholmen) aged 60-100 years (n = 2280). We used structural equation modeling to investigate whether olfactory memory in old age is best conceptualized as a distinct category, differentiated from episodic and semantic memory. Further, potential olfactory dedifferentiation and genetic associations (APOE) to olfactory function in late senescence were investigated. Results are in support of a 3-factor solution where olfactory memory, as indexed by episodic odor recognition and odor identification, is modeled separately from episodic and semantic memory for visual and verbal information. Increasing age was associated with poorer olfactory memory performance, and observed age-related deficits were further exacerbated for carriers of the APOE ε4 allele; these effects tended to be larger for olfactory memory compared to episodic and semantic memory pertaining to other sensory systems (vision, auditory). Finally, stronger correlations between olfactory and episodic memory, indicating dedifferentiation, were observed in the older age groups.

  11. Logic gates realized by nonvolatile GeTe/Sb2Te3 super lattice phase-change memory with a magnetic field input

    NASA Astrophysics Data System (ADS)

    Lu, Bin; Cheng, Xiaomin; Feng, Jinlong; Guan, Xiawei; Miao, Xiangshui

    2016-07-01

    Nonvolatile memory devices or circuits that can implement both storage and calculation are a crucial requirement for the efficiency improvement of modern computer. In this work, we realize logic functions by using [GeTe/Sb2Te3]n super lattice phase change memory (PCM) cell in which higher threshold voltage is needed for phase change with a magnetic field applied. First, the [GeTe/Sb2Te3]n super lattice cells were fabricated and the R-V curve was measured. Then we designed the logic circuits with the super lattice PCM cell verified by HSPICE simulation and experiments. Seven basic logic functions are first demonstrated in this letter; then several multi-input logic gates are presented. The proposed logic devices offer the advantages of simple structures and low power consumption, indicating that the super lattice PCM has the potential in the future nonvolatile central processing unit design, facilitating the development of massive parallel computing architecture.

  12. Dieting and Food Cue-Related Working Memory Performance

    PubMed Central

    Meule, Adrian

    2016-01-01

    Executive functioning (e.g., working memory) is tightly intertwined with self-regulation. For example, food cue-elicited craving has been found to impair working memory performance. Furthermore, current dieters have been found to show lower working memory performance than non-dieters. Recent research, however, suggests that it is crucial to consider dieting success in addition to current dieting status or restrained eating in order to reveal cognitive mechanisms that are associated with successful eating-related self-regulation. The current study investigated food cue-related working memory performance as a function of dieting status and dieting success in female students. Participants performed an n-back task with pictures of food and neutral objects. Reaction time in response to food pictures was slower than in response to neutral pictures, whereas omission errors did not differ between picture types. Current food craving was increased after performing the food block, but not after the neutral block. There was an indirect effect of current dieting status on higher food craving after the food block, which was mediated by slower reaction time to food vs. neutral pictures. Furthermore, higher dieting success was associated with fewer omission errors in the food vs. neutral block in current dieters. There were no relationships of restrained eating with current food craving and task performance. Results further highlight the need to differentiate between successful and unsuccessful dieting in addition to current dieting status or restrained eating when examining possible mechanisms of overeating or successful restraint. Although palatable food cues induce food craving regardless of dieting success, they may boost executive functioning in successful dieters, which helps them to overcome these temptations. PMID:28018277

  13. Dieting and Food Cue-Related Working Memory Performance.

    PubMed

    Meule, Adrian

    2016-01-01

    Executive functioning (e.g., working memory) is tightly intertwined with self-regulation. For example, food cue-elicited craving has been found to impair working memory performance. Furthermore, current dieters have been found to show lower working memory performance than non-dieters. Recent research, however, suggests that it is crucial to consider dieting success in addition to current dieting status or restrained eating in order to reveal cognitive mechanisms that are associated with successful eating-related self-regulation. The current study investigated food cue-related working memory performance as a function of dieting status and dieting success in female students. Participants performed an n-back task with pictures of food and neutral objects. Reaction time in response to food pictures was slower than in response to neutral pictures, whereas omission errors did not differ between picture types. Current food craving was increased after performing the food block, but not after the neutral block. There was an indirect effect of current dieting status on higher food craving after the food block, which was mediated by slower reaction time to food vs. neutral pictures. Furthermore, higher dieting success was associated with fewer omission errors in the food vs. neutral block in current dieters. There were no relationships of restrained eating with current food craving and task performance. Results further highlight the need to differentiate between successful and unsuccessful dieting in addition to current dieting status or restrained eating when examining possible mechanisms of overeating or successful restraint. Although palatable food cues induce food craving regardless of dieting success, they may boost executive functioning in successful dieters, which helps them to overcome these temptations.

  14. Memory window widening of Pt/SrBi2Ta2O9/HfO2/Si ferroelectric-gate field-effect transistors by nitriding Si

    NASA Astrophysics Data System (ADS)

    Horiuchi, Takeshi; Takahashi, Mitsue; Ohhashi, Kentaro; Sakai, Shigeki

    2009-10-01

    The optimum temperature of rapid thermal nitridation (RTN) of Si substrates was investigated for minimizing an equivalent oxide thickness (EOT) of an interfacial layer (IL) which was grown between HfO2 and Si of Pt/SrBi2Ta2O9(SBT)/HfO2/Si ferroelectric-gate field-effect transistors (FeFETs) during a post-annealing process. The RTN was performed in NH3 gas at various temperatures ranging from 800 °C to 1190 °C. As the RTN temperature was raised from 800 °C to 1080 °C, memory windows of drain current-gate voltage curves became wider. Large memory windows were obtained at the range from 1020 °C to 1130 °C. The maximum was 1.36 V obtained at 1080 °C. It was 10% larger than the typical values of Pt/SBT/HfO2/Si FeFETs without the RTN. At higher RTN temperatures than 1080 °C, the memory windows tended to decrease. At 800 °C and 1190 °C, all layer boundaries among SBT-HfO2-IL-Si seemed unclear in scanning transmission electron microscopic views probably due to material diffusions. The optimum RTN temperature for minimizing the EOT of the IL and maximizing the memory window of the Pt/SBT/HfO2/SiNx/Si FeFET was 1080 °C. The FeFET using the Si processed by the RTN at 1080 °C also showed good retentions without significant degradations over two days.

  15. The differential effects of emotional salience on direct associative and relational memory during a nap.

    PubMed

    Alger, Sara E; Payne, Jessica D

    2016-12-01

    Relational memories are formed from shared components between directly learned memory associations, flexibly linking learned information to better inform future judgments. Sleep has been found to facilitate both direct associative and relational memories. However, the impact of incorporating emotionally salient information into learned material and the interaction of emotional salience and sleep in facilitating both types of memory is unknown. Participants encoded two sets of picture pairs, with either emotionally negative or neutral objects paired with neutral faces. The same objects were present in both sets, paired with two different faces across the sets. Baseline memory for these directly paired associates was tested immediately after encoding, followed by either a 90-min nap opportunity or wakefulness. Five hours after learning, a surprise test assessed relational memory, the indirect association between two faces paired with the same object during encoding, followed by a retest of direct associative memory. Overall, negative information was remembered better than neutral for directly learned pairs. A nap facilitated both preservation of direct associative memories and formation of relational memories, compared to remaining awake. Interestingly, however, this sleep benefit was observed specifically for neutral directly paired associates, while both neutral and negative relational associations benefitted from a nap. Finally, REM sleep played opposing roles in neutral direct and relational associative memory formation, with more REM sleep leading to forgetting of direct associations but promoting relational associations, suggesting that, while not benefitting memory consolidation for directly learned details, REM sleep may foster the memory reorganization needed for relational memory.

  16. Knowledge of memory functions in European and Asian American adults and children: the relation to autobiographical memory.

    PubMed

    Wang, Qi; Koh, Jessie Bee Kim; Song, Qingfang; Hou, Yubo

    2015-01-01

    This study investigated explicit knowledge of autobiographical memory functions using a newly developed questionnaire. European and Asian American adults (N = 57) and school-aged children (N = 68) indicated their agreement with 13 statements about why people think about and share memories pertaining to four broad functions-self, social, directive and emotion regulation. Children were interviewed for personal memories concurrently with the memory function knowledge assessment and again 3 months later. It was found that adults agreed to the self, social and directive purposes of memory to a greater extent than did children, whereas European American children agreed to the emotion regulation purposes of memory to a greater extent than did European American adults. Furthermore, European American children endorsed more self and emotion regulation functions than did Asian American children, whereas Asian American adults endorsed more directive functions than did European American adults. Children's endorsement of memory functions, particularly social functions, was associated with more detailed and personally meaningful memories. These findings are informative for the understanding of developmental and cultural influences on memory function knowledge and of the relation of such knowledge to autobiographical memory development.

  17. Memory

    MedlinePlus

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

  18. Cognitive dissonance resolution is related to episodic memory.

    PubMed

    Salti, Moti; El Karoui, Imen; Maillet, Mathurin; Naccache, Lionel

    2014-01-01

    The notion that our past choices affect our future behavior is certainly one of the most influential concepts of social psychology since its first experimental report in the 50 s, and its initial theorization by Festinger within the "cognitive dissonance" framework. Using the free choice paradigm (FCP), it was shown that choosing between two similarly rated items made subjects reevaluate the chosen items as more attractive and the rejected items as less attractive. However, in 2010 a major work by Chen and Risen revealed a severe statistical flaw casting doubt on most previous studies. Izuma and colleagues (2010) supplemented the traditional FCP with original control conditions and concluded that the effect observed could not be solely attributed to this methodological flaw. In the present work we aimed at establishing the existence of genuine choice-induced preference change and characterizing this effect. To do so, we replicated Izuma et al.' study and added a new important control condition which was absent from the original study. Moreover, we added a memory test in order to measure the possible relation between episodic memory of choices and observed behavioral effects. In two experiments we provide experimental evidence supporting genuine choice-induced preference change obtained with FCP. We also contribute to the understanding of the phenomenon by showing that choice-induced preference change effects are strongly correlated with episodic memory.

  19. Cognitive Dissonance Resolution Is Related to Episodic Memory

    PubMed Central

    Maillet, Mathurin; Naccache, Lionel

    2014-01-01

    The notion that our past choices affect our future behavior is certainly one of the most influential concepts of social psychology since its first experimental report in the 50 s, and its initial theorization by Festinger within the “cognitive dissonance” framework. Using the free choice paradigm (FCP), it was shown that choosing between two similarly rated items made subjects reevaluate the chosen items as more attractive and the rejected items as less attractive. However, in 2010 a major work by Chen and Risen revealed a severe statistical flaw casting doubt on most previous studies. Izuma and colleagues (2010) supplemented the traditional FCP with original control conditions and concluded that the effect observed could not be solely attributed to this methodological flaw. In the present work we aimed at establishing the existence of genuine choice-induced preference change and characterizing this effect. To do so, we replicated Izuma et al.’ study and added a new important control condition which was absent from the original study. Moreover, we added a memory test in order to measure the possible relation between episodic memory of choices and observed behavioral effects. In two experiments we provide experimental evidence supporting genuine choice-induced preference change obtained with FCP. We also contribute to the understanding of the phenomenon by showing that choice-induced preference change effects are strongly correlated with episodic memory. PMID:25264950

  20. Age-related differences in recognition memory for items and associations: contribution of individual differences in working memory and metamemory.

    PubMed

    Bender, Andrew R; Raz, Naftali

    2012-09-01

    Ability to form new associations between unrelated items is particularly sensitive to aging, but the reasons for such differential vulnerability are unclear. In this study, we examined the role of objective and subjective factors (working memory and beliefs about memory strategies) on differential relations of age with recognition of items and associations. Healthy adults (N = 100, age 21 to 79) studied word pairs, completed item and association recognition tests, and rated the effectiveness of shallow (e.g., repetition) and deep (e.g., imagery or sentence generation) encoding strategies. Advanced age was associated with reduced working memory (WM) capacity and poorer associative recognition. In addition, reduced WM capacity, beliefs in the utility of ineffective encoding strategies, and lack of endorsement of effective ones were independently associated with impaired associative memory. Thus, maladaptive beliefs about memory in conjunction with reduced cognitive resources account in part for differences in associative memory commonly attributed to aging.

  1. Is sleep-related verbal memory consolidation impaired in sleepwalkers?

    PubMed

    Uguccioni, Ginevra; Pallanca, Olivier; Golmard, Jean-Louis; Leu-Semenescu, Smaranda; Arnulf, Isabelle

    2015-04-01

    In order to evaluate verbal memory consolidation during sleep in subjects experiencing sleepwalking or sleep terror, 19 patients experiencing sleepwalking/sleep terror and 19 controls performed two verbal memory tasks (16-word list from the Free and Cued Selective Reminding Test, and a 220- and 263-word modified story recall test) in the evening, followed by nocturnal video polysomnography (n = 29) and morning recall (night-time consolidation after 14 h, n = 38). The following morning, they were given a daytime learning task using the modified story recall test in reverse order, followed by an evening recall test after 9 h of wakefulness (daytime consolidation, n = 38). The patients experiencing sleepwalking/sleep terror exhibited more frequent awakenings during slow-wave sleep and longer wakefulness after sleep onset than the controls. Despite this reduction in sleep quality among sleepwalking/sleep terror patients, they improved their scores on the verbal tests the morning after sleep compared with the previous evening (+16 ± 33%) equally well as the controls (+2 ± 13%). The performance of both groups worsened during the daytime in the absence of sleep (-16 ± 15% for the sleepwalking/sleep terror group and -14 ± 11% for the control group). There was no significant correlation between the rate of memory consolidation and any of the sleep measures. Seven patients experiencing sleepwalking also sleep-talked during slow-wave sleep, but their sentences were unrelated to the tests or the list of words learned during the evening. In conclusion, the alteration of slow-wave sleep during sleepwalking/sleep terror does not noticeably impact on sleep-related verbal memory consolidation.

  2. Spatial relational memory in 9-month-old macaque monkeys.

    PubMed

    Lavenex, Pierre; Lavenex, Pamela Banta

    2006-01-01

    This experiment assesses spatial and nonspatial relational memory in freely moving 9-mo-old and adult (11-13-yr-old) macaque monkeys (Macaca mulatta). We tested the use of proximal landmarks, two different objects placed at the center of an open-field arena, as conditional cues allowing monkeys to predict the location of food rewards hidden in one of two sets of three distinct locations. Monkeys were tested in two different conditions: (1) when local visual cues marked the two sets of potentially baited locations, so that monkeys could use both local and spatial information to discriminate these locations from never-baited locations; and (2) when no local visual cues marked the two sets of potentially baited locations, so that monkeys had to rely on a spatial relational representation of the environment to discriminate these locations. No 9-mo-old or adult monkey associated the presence of the proximal landmarks, at the center of the arena, with the presence of food in one set of three distinct locations. All monkeys, however, discriminated the potentially baited locations in the presence of local visual cues, thus providing evidence of visual discrimination learning. More importantly, all 9-mo-old monkeys tested discriminated the potentially baited locations in absence of the local visual cues, thus exhibiting evidence of spatial relational learning. These findings indicate that spatial memory processes characterized by a relational representation of the environment are present as early as 9 mo of age in macaque monkeys.

  3. Ageing-related stereotypes in memory: When the beliefs come true.

    PubMed

    Bouazzaoui, Badiâa; Follenfant, Alice; Ric, François; Fay, Séverine; Croizet, Jean-Claude; Atzeni, Thierry; Taconnat, Laurence

    2016-01-01

    Age-related stereotype concerns culturally shared beliefs about the inevitable decline of memory with age. In this study, stereotype priming and stereotype threat manipulations were used to explore the impact of age-related stereotype on metamemory beliefs and episodic memory performance. Ninety-two older participants who reported the same perceived memory functioning were divided into two groups: a threatened group and a non-threatened group (control). First, the threatened group was primed with an ageing stereotype questionnaire. Then, both groups were administered memory complaints and memory self-efficacy questionnaires to measure metamemory beliefs. Finally, both groups were administered the Logical Memory task to measure episodic memory, for the threatened group the instructions were manipulated to enhance the stereotype threat. Results indicated that the threatened individuals reported more memory complaints and less memory efficacy, and had lower scores than the control group on the logical memory task. A multiple mediation analysis revealed that the stereotype threat effect on the episodic memory performance was mediated by both memory complaints and memory self-efficacy. This study revealed that stereotype threat impacts belief in one's own memory functioning, which in turn impairs episodic memory performance.

  4. Inverse relation between cortisol and anger and their relation to performance and explicit memory.

    PubMed

    Kazén, Miguel; Kuenne, Thomas; Frankenberg, Heiko; Quirin, Markus

    2012-09-01

    Cortisol has been found to increase in response to social evaluative threat. However, little is known about the cortisol response to induced anger. Thus, in the present study, we investigated the cortisol response to anger induction and its effects on performance and explicit memory. A variant of the Montreal Stress Imaging Task (MIST; Dedovic et al., 2005) was used to induce anger in 17 male and 17 female students. Consistent with previous observations, a significant decrease in cortisol was found from pre to post manipulation which was inversely related to increases in subjective anger. Moreover, whereas anger increase was related to impairments in performance, cortisol reduction was inversely related to cognitive performance and explicit memory (recall and recognition of persons' features in a social memory task). The adaptive value of an increase in cortisol in response to fear or uncontrollability and of a decrease in cortisol in response to anger will be discussed.

  5. Decay of Iconic Memory Traces Is Related to Psychometric Intelligence: A Fixed-Links Modeling Approach

    ERIC Educational Resources Information Center

    Miller, Robert; Rammsayer, Thomas H.; Schweizer, Karl; Troche, Stefan J.

    2010-01-01

    Several memory processes have been examined regarding their relation to psychometric intelligence with the exception of sensory memory. This study examined the relation between decay of iconic memory traces, measured with a partial-report task, and psychometric intelligence, assessed with the Berlin Intelligence Structure test, in 111…

  6. Death-Related versus Fond Memories of a Deceased Attachment Figure: Examining Emotional Arousal

    ERIC Educational Resources Information Center

    Rochman, Daniel

    2013-01-01

    Grieving is infused by memories and emotions. In this study, bereaved participants recalled either death-related or fond memories of their loved ones. Their emotional arousal was examined via physiologic and voice analytic measures. Both death-related and fond memories generated an acoustic profile indicative of sadness (reflected by voice quality…

  7. The Differential Relations between Verbal, Numerical and Spatial Working Memory Abilities and Children's Reading Comprehension

    ERIC Educational Resources Information Center

    Oakhill, Jane; Yuill, Nicola; Garnham, Alan

    2011-01-01

    Working memory predicts children's reading comprehension but it is not clear whether this relation is due to a modality-specific or general working memory. This study, which investigated the relations between children's reading skills and working memory (WM) abilities in 3 modalities, extends previous work by including measures of both reading…

  8. Working-memory performance is related to spatial breadth of attention.

    PubMed

    Kreitz, Carina; Furley, Philip; Memmert, Daniel; Simons, Daniel J

    2015-11-01

    Working memory and attention are closely related constructs. Models of working memory often incorporate an attention component, and some even equate working memory and attentional control. Although some attention-related processes, including inhibitory control of response conflict and interference resolution, are strongly associated with working memory, for other aspects of attention the link is less clear. We examined the association between working-memory performance and attentional breadth, the ability to spread attention spatially. If the link between attention and working memory is broader than inhibitory and interference resolution processes, then working-memory performance might also be associated with other attentional abilities, including attentional breadth. We tested 123 participants on a variety of working-memory and attentional-breadth measures, finding a strong correlation between performances on these two types of tasks. This finding demonstrates that the link between working memory and attention extends beyond inhibitory processes.

  9. Memory.

    ERIC Educational Resources Information Center

    McKean, Kevin

    1983-01-01

    Discusses current research (including that involving amnesiacs and snails) into the nature of the memory process, differentiating between and providing examples of "fact" memory and "skill" memory. Suggests that three brain parts (thalamus, fornix, mammilary body) are involved in the memory process. (JN)

  10. Working Memory and Its Relation to Deterministic Sequence Learning

    PubMed Central

    Martini, Markus; Furtner, Marco R.; Sachse, Pierre

    2013-01-01

    Is there a relation between working memory (WM) and incidental sequence learning? Nearly all of the earlier investigations in the role of WM capacity (WMC) in sequence learning suggest no correlations in incidental learning conditions. However, the theoretical view of WM and operationalization of WMC made strong progress in recent years. The current study related performance in a coordination and transformation task to sequence knowledge in a four-choice incidental deterministic serial reaction time (SRT) task and a subsequent free generation task. The response-to-stimulus interval (RSI) was varied between 0 ms and 300 ms. Our results show correlations between WMC and error rates in condition RSI 0 ms. For condition RSI 300 ms we found relations between WMC and sequence knowledge in the SRT task as well as between WMC and generation task performance. Theoretical implications of these findings for ongoing processes during sequence learning and retrieval of sequence knowledge are discussed. PMID:23409148

  11. Relation of Physical Activity to Memory Functioning in Older Adults: The Memory Workout Program.

    ERIC Educational Resources Information Center

    Rebok, George W.; Plude, Dana J.

    2001-01-01

    The Memory Workout, a CD-ROM program designed to help older adults increase changes in physical and cognitive activity influencing memory, was tested with 24 subjects. Results revealed a significant relationship between exercise time, exercise efficacy, and cognitive function, as well as interest in improving memory and physical activity.…

  12. Reward Retroactively Enhances Memory Consolidation for Related Items

    ERIC Educational Resources Information Center

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

    2017-01-01

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

  13. Entropic Uncertainty Relation and Information Exclusion Relation for multiple measurements in the presence of quantum memory

    NASA Astrophysics Data System (ADS)

    Zhang, Jun; Zhang, Yang; Yu, Chang-Shui

    2015-06-01

    The Heisenberg uncertainty principle shows that no one can specify the values of the non-commuting canonically conjugated variables simultaneously. However, the uncertainty relation is usually applied to two incompatible measurements. We present tighter bounds on both entropic uncertainty relation and information exclusion relation for multiple measurements in the presence of quantum memory. As applications, three incompatible measurements on Werner state and Horodecki’s bound entangled state are investigated in details.

  14. Entropic Uncertainty Relation and Information Exclusion Relation for multiple measurements in the presence of quantum memory.

    PubMed

    Zhang, Jun; Zhang, Yang; Yu, Chang-shui

    2015-06-29

    The Heisenberg uncertainty principle shows that no one can specify the values of the non-commuting canonically conjugated variables simultaneously. However, the uncertainty relation is usually applied to two incompatible measurements. We present tighter bounds on both entropic uncertainty relation and information exclusion relation for multiple measurements in the presence of quantum memory. As applications, three incompatible measurements on Werner state and Horodecki's bound entangled state are investigated in details.

  15. FIFTH SEMINAR IN MEMORY OF D.N. KLYSHKO: Two schemes of logic gates for one-way quantum computing

    NASA Astrophysics Data System (ADS)

    Basharov, A. M.; Gorbachev, V. N.

    2007-12-01

    Two schemes of measurement-based gates are considered. The first scheme uses atomic cluster states generated by using the proposed cooperative process involving classical fields. The second scheme is based on the quantum correlation of biphotons and allows encoding classical information by the states of a quantum system.

  16. Age-Related Differences in Learning Disabled and Skilled Readers' Working Memory.

    ERIC Educational Resources Information Center

    Swanson, H. Lee

    2003-01-01

    Examined whether age-related working memory deficits in learning disabled (LD) readers across four age groups (7, 10, 13, and 20) reflected retrieval efficiency or storage capacity problems. Found that LD readers' working memory performance was inferior to skilled readers' on verbal and visual-spatial working memory tasks across all ages.…

  17. Age-related differences in sleep-based memory consolidation: A meta-analysis.

    PubMed

    Gui, Wen-Jun; Li, Hui-Jie; Guo, Yu-Hua; Peng, Peng; Lei, Xu; Yu, Jing

    2017-02-02

    A period of post-learning sleep benefits memory consolidation compared with an equal-length wake interval. However, whether this sleep-based memory consolidation changes as a function of age remains controversial. Here we report a meta-analysis that investigates the age differences in the sleep-based memory consolidation in two types of memory: declarative memory and procedural memory. The meta-analysis included 22 comparisons of the performance between young adults (N =640) and older adults (N =529) on behavioral tasks measuring sleep-based memory consolidation. Our results showed a significant overall sleep-based beneficial effect in young adults but not in older adults. However, further analyses suggested that the age differences were mainly manifested in sleep-based declarative memory consolidation but not in procedural memory consolidation. We discussed the possible underlying mechanisms for the age-related degradation in sleep-based memory consolidation. Further research is needed to determine the crucial components for sleep-related memory consolidation in older adults such as age-related changes in neurobiological and cardiovascular functions, which may play an important role in this context and have the potential to delineate the interrelationships between age-related changes in sleep and memory.

  18. Examining factors involved in stress-related working memory impairments: Independent or conditional effects?

    PubMed

    Banks, Jonathan B; Tartar, Jaime L; Tamayo, Brittney A

    2015-12-01

    A large and growing body of research demonstrates the impact of psychological stress on working memory. However, the typical study approach tests the effects of a single biological or psychological factor on changes in working memory. The current study attempted to move beyond the standard single-factor assessment by examining the impact of 2 possible factors in stress-related working memory impairments. To this end, 60 participants completed a working memory task before and after either a psychological stressor writing task or a control writing task and completed measures of both cortisol and mind wandering. We also included a measure of state anxiety to examine the direct and indirect effect on working memory. We found that mind wandering mediated the relationship between state anxiety and working memory at the baseline measurement. This indirect relationship was moderated by cortisol, such that the impact of mind wandering on working memory increased as cortisol levels increased. No overall working memory impairment was observed following the stress manipulation, but increases in state anxiety and mind wandering were observed. State anxiety and mind wandering independently mediated the relationship between change in working memory and threat perception. The indirect paths resulted in opposing effects on working memory. Combined, the findings from this study suggest that cortisol enhances the impact of mind wandering on working memory, that state anxiety may not always result in stress-related working memory impairments, and that high working memory performance can protect against mind wandering.

  19. Prospective and Episodic Memory in Relation to Hippocampal Volume in Adults with Spina Bifida Myelomeningocele

    PubMed Central

    Treble-Barna, Amery; Juranek, Jenifer; Stuebing, Karla K.; Cirino, Paul T.; Dennis, Maureen; Fletcher, Jack M.

    2014-01-01

    The present study examined prospective and episodic memory in relation to age, functional independence, and hippocampal volume in younger to middle-aged adults with spina bifida myelomeningocele (SBM) and typically developing (TD) adults. Prospective and episodic memory, as well as hippocampal volume, were reduced in adults with SBM relative to TD adults. Neither memory performance nor hippocampal volume showed greater decrements in older adults. Lower hippocampal volume was associated with reduced prospective memory in adults with SBM, and this relation was specific to the hippocampus and not to a contrast structure, the amygdala. Prospective memory mediated the relation between hippocampal volume and functional independence in adults with SBM. The results add to emerging evidence for reduced memory function in adults with SBM, and provide quantitative evidence for compromised hippocampal macrostructure as a neural correlate of reduced memory in this population. PMID:25068670

  20. Gaming is related to enhanced working memory performance and task-related cortical activity.

    PubMed

    Moisala, M; Salmela, V; Hietajärvi, L; Carlson, S; Vuontela, V; Lonka, K; Hakkarainen, K; Salmela-Aro, K; Alho, K

    2017-01-15

    Gaming experience has been suggested to lead to performance enhancements in a wide variety of working memory tasks. Previous studies have, however, mostly focused on adult expert gamers and have not included measurements of both behavioral performance and brain activity. In the current study, 167 adolescents and young adults (aged 13-24 years) with different amounts of gaming experience performed an n-back working memory task with vowels, with the sensory modality of the vowel stream switching between audition and vision at random intervals. We studied the relationship between self-reported daily gaming activity, working memory (n-back) task performance and related brain activity measured using functional magnetic resonance imaging (fMRI). The results revealed that the extent of daily gaming activity was related to enhancements in both performance accuracy and speed during the most demanding (2-back) level of the working memory task. This improved working memory performance was accompanied by enhanced recruitment of a fronto-parietal cortical network, especially the dorsolateral prefrontal cortex. In contrast, during the less demanding (1-back) level of the task, gaming was associated with decreased activity in the same cortical regions. Our results suggest that a greater degree of daily gaming experience is associated with better working memory functioning and task difficulty-dependent modulation in fronto-parietal brain activity already in adolescence and even when non-expert gamers are studied. The direction of causality within this association cannot be inferred with certainty due to the correlational nature of the current study.

  1. Memory for relations in the short term and the long term after medial temporal lobe damage.

    PubMed

    Squire, Larry R

    2017-02-11

    A central idea about the organization of declarative memory and the function of the hippocampus is that the hippocampus provides for the coding of relationships between items. A question arises whether this idea refers to the process of forming long-term memory or whether, as some studies have suggested, memory for relations might depend on the hippocampus even at short retention intervals and even when the task falls within the province of short-term (working) memory. The latter formulation appears to place the operation of relational memory into conflict with the idea that working memory is independent of medial temporal lobe (MTL) structures. In this report, the concepts of relational memory and working memory are discussed in the light of a simple demonstration experiment. Patients with MTL lesions successfully learned and recalled two word pairs when tested directly after learning but failed altogether when tested after a delay. The results do not contradict the idea that the hippocampus has a fundamental role in relational memory. However, there is a need for further elaboration and specification of the idea in order to explain why patients with MTL lesions can establish relational memory in the short term but not in long-term memory. © 2017 Wiley Periodicals, Inc.

  2. Children’s Forgetting of Pain-Related Memories

    PubMed Central

    Briere, Jennifer L.; von Baeyer, Carl L.

    2016-01-01

    Objective Given that forgetting negative experiences can help children cope with these experiences, we examined their ability to forget negative aspects of painful events. Methods 86 children aged 7–15 years participated in a retrieval-induced forgetting task whereby they repeatedly retrieved positive details of a physically painful experience, and an experimental pain task (cold-pressor task). Results Repeatedly retrieving positive details of a prior pain experience produced forgetting of the negative aspects of that experience. Pain-related self-efficacy predicted retrieval-induced forgetting; children with a poorer belief in their ability to cope with pain experienced less forgetting. Children who had a more difficult time forgetting prior negative experiences were more anxious about the pain task and reported higher pain thresholds. Conclusions Understanding children’s memory for painful experiences may help improve their pain management and coping ability. PMID:26666267

  3. Experimental Study of Floating-Gate-Type Metal-Oxide-Semiconductor Capacitors with Nanosize Triangular Cross-Sectional Tunnel Areas for Low Operating Voltage Flash Memory Application

    NASA Astrophysics Data System (ADS)

    Liu, Yongxun; Guo, Ruofeng; Kamei, Takahiro; Matsukawa, Takashi; Endo, Kazuhiko; O'uchi, Shinichi; Tsukada, Junichi; Yamauchi, Hiromi; Ishikawa, Yuki; Hayashida, Tetsuro; Sakamoto, Kunihiro; Ogura, Atsushi; Masahara, Meishoku

    2012-06-01

    The floating-gate (FG)-type metal-oxide-semiconductor (MOS) capacitors with planar (planar-MOS) and three-dimensional (3D) nanosize triangular cross-sectional tunnel areas (3D-MOS) have successfully been fabricated by introducing rapid thermal oxidation (RTO) and postdeposition annealing (PDA), and their electrical characteristics between the control gate (CG) and FG have been systematically compared. It was experimentally found in both planar- and 3D-MOS capacitors that the uniform and higher breakdown voltages are obtained by introducing RTO owing to the high-quality thermal oxide formation on the surface and etched edge regions of the n+ polycrystalline silicon (poly-Si) FG, and the leakage current is highly suppressed after PDA owing to the improved quality of the tetraethylorthosilicate (TEOS) silicon dioxide (SiO2) between CG and FG. Moreover, a lower breakdown voltage between CG and FG was obtained in the fabricated 3D-MOS capacitors as compared with that of planar-MOS capacitors thanks to the enhanced local electric field at the tips of triangular tunnel areas. The developed nanosize triangular cross-sectional tunnel area is useful for the fabrication of low operating voltage flash memories.

  4. Fabrication and Characterization of Ferroelectric Gate Field-Effect Transistor Memory Based on Ferroelectric-Insulator Interface Conduction

    NASA Astrophysics Data System (ADS)

    Lee, Bong Yeon; Minami, Takaki; Kanashima, Takeshi; Okuyama, Masanori

    2006-11-01

    A new type of ferroelectric gate field-effect transistor (FET) using ferroelectric-insulator interface conduction has been proposed. Drain current flows along the interface between the ferroelectric and insulator layers and requires no semiconductor. The channel region of the FET is composed of a Pt/insulator HfO2/ferroelectric Pb(Zr0.52Ti0.48)O3 (PZT)/Pt/TiO2/SiO2/Si multilayer, and the source and drain areas are formed at the interface of the PZT and HfO2 films. Drain current versus gate voltage characteristics show a clockwise hysteresis loop similar to that for a conventional p-channel transistor. The FET shows that the on/off ratio of the conduction current is within 105 to 106 and that the off-state current is about 10-10 A.

  5. The Relations between Early Working Memory Abilities and Later Developing Reading Skills: A Longitudinal Study from Kindergarten to Fifth Grade

    ERIC Educational Resources Information Center

    Nevo, Einat; Bar-Kochva, Irit

    2015-01-01

    This study investigated the relations of early working-memory abilities (phonological and visual-spatial short-term memory [STM] and complex memory and episodic buffer memory) and later developing reading skills. Sixty Hebrew-speaking children were followed from kindergarten through Grade 5. Working memory was tested in kindergarten and reading in…

  6. Age differences in short-term memory binding are related to working memory performance across the lifespan.

    PubMed

    Fandakova, Yana; Sander, Myriam C; Werkle-Bergner, Markus; Shing, Yee Lee

    2014-03-01

    Memory performance increases during childhood and adolescence, and decreases in old age. Among younger adults, better ability to bind items to the context in which they were experienced is associated with higher working memory performance (Oberauer, 2005). Here, we examined the extent to which age differences in binding contribute to life span age differences in short-term memory (STM). Younger children (N = 85; 10 to 12 years), teenagers (N = 41; 13 to 15 years), younger adults (N = 84; 20 to 25 years), and older adults (N = 86; 70 to 75 years) worked on global and local short-term recognition tasks that are assumed to measure item and item-context memory, respectively. Structural equation models showed that item-context bindings are functioning less well in children and older adults compared with younger adults and teenagers. This result suggests protracted development of the ability to form and recollect detailed short-term memories, and decline of this ability in aging. Across all age groups, better item-context binding was associated with higher working memory performance, indicating that developmental differences in binding mechanisms are closely related to working memory development in childhood and old age.

  7. Age-related differences in working memory updating components.

    PubMed

    Linares, Rocío; Bajo, M Teresa; Pelegrina, Santiago

    2016-07-01

    The aim of this study was to investigate possible age-related changes throughout childhood and adolescence in different component processes of working memory updating (WMU): retrieval, transformation, and substitution. A set of numerical WMU tasks was administered to four age groups (8-, 11-, 14-, and 21-year-olds). To isolate the effect of each of the WMU components, participants performed different versions of a task that included different combinations of the WMU components. The results showed an expected overall decrease in response times and an increase in accuracy performance with age. Most important, specific age-related changes in the retrieval component were found, demonstrating that the effect of retrieval on accuracy was larger in children than in adolescents or young adults. These findings indicate that the availability of representations from outside the focus of attention may change with age. Thus, the retrieval component of updating could contribute to the age-related changes observed in the performance of many updating tasks.

  8. Are Memory Self-Efficacy and Memory Performance Related? A Meta-Analysis

    ERIC Educational Resources Information Center

    Beaudoin, Marine; Desrichard, Olivier

    2011-01-01

    The association between memory self-efficacy (MSE) and memory performance is highly documented in the literature. However, previous studies have produced inconsistent results, and there is no consensus on the existence of a significant link between these two variables. In order to evaluate whether or not the effect size of the MSE-memory…

  9. Content Analysis of Memory and Memory-Related Research Studies on Children with Hearing Loss

    ERIC Educational Resources Information Center

    Dogan, Murat; Hasanoglu, Gülcihan

    2016-01-01

    Memory plays a profound role in explaining language development, academic learning, and learning disabilities. Even though there is a large body of research on language development, literacy skills, other academic skills, and intellectual characteristics of children with hearing loss, there is no holistic study on their memory processes.…

  10. Stress, glucocorticoids and memory: implications for treating fear-related disorders.

    PubMed

    de Quervain, Dominique; Schwabe, Lars; Roozendaal, Benno

    2017-01-01

    Glucocorticoid stress hormones are crucially involved in modulating mnemonic processing of emotionally arousing experiences. They enhance the consolidation of new memories, including those that extinguish older memories, but impair the retrieval of information stored in long-term memory. As strong aversive memories lie at the core of several fear-related disorders, including post-traumatic stress disorder and phobias, the memory-modulating properties of glucocorticoids have recently become of considerable translational interest. Clinical trials have provided the first evidence that glucocorticoid-based pharmacotherapies aimed at attenuating aversive memories might be helpful in the treatment of fear-related disorders. Here, we review important advances in the understanding of how glucocorticoids mediate stress effects on memory processes, and discuss the translational potential of these new conceptual insights.

  11. Systems and methods for detecting a failure event in a field programmable gate array

    NASA Technical Reports Server (NTRS)

    Ng, Tak-Kwong (Inventor); Herath, Jeffrey A. (Inventor)

    2009-01-01

    An embodiment generally relates to a method of self-detecting an error in a field programmable gate array (FPGA). The method includes writing a signature value into a signature memory in the FPGA and determining a conclusion of a configuration refresh operation in the FPGA. The method also includes reading an outcome value from the signature memory.

  12. Distortion component analysis of outer hair cell motility-related gating charge.

    PubMed

    Takahashi, S; Santos-Sacchi, J

    1999-06-01

    The underlying Boltzmann characteristics of motility-related gating currents of the outer hair cell (OHC) are predicted to generate distortion components in response to sinusoidal transmembrane voltages. We studied this distortion since it reflects the mechanical activity of the cell that may contribute to peripheral auditory system distortion. Distortion components in the OHC electrical response were analyzed using the whole-cell voltage clamp technique, under conditions where ionic conductances were blocked. Single or double-sinusoidal transmembrane voltage stimulation was delivered at various holding voltages, and distortion components of the current responses were detected by Fourier analysis. Current response magnitude and phase of each distortion component as a function of membrane potential were compared with characteristics of the voltage-dependent capacitance, obtained by voltage stair-step transient analysis or dual-frequency admittance analysis. The sum distortion was most prominent among the distortion components at all holding voltages. Notches in the sum (f1+f2), difference (f2-f1) and second harmonic (2f) components occur at the voltage where peak voltage-dependent capacitance resides (VpkCm). Rapid phase reversals also occurred at VpkCm, but phase remained fairly stable at more depolarized and hyperpolarized potentials. Thus, it is possible to extract Boltzmann parameters of the motility-related charge movement from these distortion components. In fact, we have developed a technique to follow changes in the voltage dependence of OHC motility and charge movement by tracking the voltage at phase reversal of the f2-f1 product. When intracellular turgor pressure was changed, VpkCm and distortion notch voltages shifted in the same direction. These data have important implications for understanding cochlear nonlinearity, and more generally, indicate the usefulness of distortion analysis to study displacement currents.

  13. Modeling Age-Related Differences in Immediate Memory Using SIMPLE

    ERIC Educational Resources Information Center

    Surprenant, Aimee M.; Neath, Ian; Brown, Gordon D. A.

    2006-01-01

    In the SIMPLE model (Scale Invariant Memory and Perceptual Learning), performance on memory tasks is determined by the locations of items in multidimensional space, and better performance is associated with having fewer close neighbors. Unlike most previous simulations with SIMPLE, the ones reported here used measured, rather than assumed,…

  14. On the Law Relating Processing to Storage in Working Memory

    ERIC Educational Resources Information Center

    Barrouillet, Pierre; Portrat, Sophie; Camos, Valerie

    2011-01-01

    "Working memory" is usually defined in cognitive psychology as a system devoted to the simultaneous processing and maintenance of information. However, although many models of working memory have been put forward during the last decades, they often leave underspecified the dynamic interplay between processing and storage. Moreover, the account of…

  15. Desensitization of α7 Nicotinic Receptor Is Governed by Coupling Strength Relative to Gate Tightness*

    PubMed Central

    Zhang, Jianliang; Xue, Fenqin; Whiteaker, Paul; Li, Chaokun; Wu, Wen; Shen, Benchang; Huang, Yao; Lukas, Ronald J.; Chang, Yongchang

    2011-01-01

    Binding of a neurotransmitter to its membrane receptor opens an integral ion conducting pore. However, prolonged exposure to the neurotransmitter drives the receptor to a refractory state termed desensitization, which plays an important role in shaping synaptic transmission. Despite intensive research in the past, the structural mechanism of desensitization is still elusive. Using mutagenesis and voltage clamp in an oocyte expression system, we provide several lines of evidence supporting a novel hypothesis that uncoupling between binding and gating machinery is the underlying mechanism for α7 nicotinic receptor (nAChR) desensitization. First, the decrease in gate tightness was highly correlated to the reduced desensitization. Second, nonfunctional mutants in three important coupling loops (loop 2, loop 7, and the M2-M3 linker) could be rescued by a gating mutant. Furthermore, the decrease in coupling strength in these rescued coupling loop mutants reversed the gating effect on desensitization. Finally, coupling between M1 and hinge region of the M2-M3 linker also influenced the receptor desensitization. Thus, the uncoupling between N-terminal domain and transmembrane domain, governed by the balance of coupling strength and gate tightness, underlies the mechanism of desensitization for the α7 nAChR. PMID:21610071

  16. Goal orientation and self-efficacy in relation to memory in adulthood

    PubMed Central

    Hastings, Erin C.; West, Robin L.

    2011-01-01

    The achievement goal framework (Dweck, 1986) has been well-established in children and college-students, but has rarely been examined empirically with older adults. The current study, including younger and older adults, examined the effects of memory self-efficacy, learning goals (focusing on skill mastery over time) and performance goals (focusing on performance outcome evaluations) on memory performance. Questionnaires measured memory self-efficacy and general orientation toward learning and performance goals; free and cued recall was assessed in a subsequent telephone interview. As expected, age was negatively related and education was positively related to memory self-efficacy, and memory self-efficacy was positively related to memory, in a structural equation model. Age was also negatively related to memory performance. Results supported the positive impact of learning goals and the negative impact of performance goals on memory self-efficacy. There was no significant direct effect of learning or performance goals on memory performance; their impact occurred via their effect on memory self-efficacy. The present study supports past research suggesting that learning goals are beneficial, and performance goals are maladaptive, for self-efficacy and learning, and validates the achievement goal framework in a sample including older adults. PMID:21728891

  17. Medial prefrontal functional connectivity--relation to memory self-appraisal accuracy in older adults with and without memory disorders.

    PubMed

    Ries, Michele L; McLaren, Donald G; Bendlin, Barbara B; Guofanxu; Rowley, Howard A; Birn, Rasmus; Kastman, Erik K; Sager, Mark A; Asthana, Sanjay; Johnson, Sterling C

    2012-04-01

    It is tentatively estimated that 25% of people with early Alzheimer's disease (AD) show impaired awareness of disease-related changes in their own cognition. Research examining both normative self-awareness and altered awareness resulting from brain disease or injury points to the central role of the medial prefrontal cortex (MPFC) in generating accurate self-appraisals. The current project builds on this work - examining changes in MPFC functional connectivity that correspond to impaired self-appraisal accuracy early in the AD time course. Our behavioral focus was self-appraisal accuracy for everyday memory function, and this was measured using the Memory Function Scale of the Memory Awareness Rating Scale - an instrument psychometrically validated for this purpose. Using regression analysis of data from people with healthy memory (n=12) and people with impaired memory due to amnestic mild cognitive impairment or early AD (n=12), we tested the hypothesis that altered MPFC functional connectivity - particularly with other cortical midline structures and dorsolateral prefrontal cortex - explains variation in memory self-appraisal accuracy. We spatially constrained (i.e., explicitly masked) our regression analyses to those regions that work in conjunction with the MPFC to evoke self-appraisals in a normative group. This empirically derived explicit mask was generated from the result of a psychophysiological interaction analysis of fMRI self-appraisal task data in a separate, large group of cognitively healthy individuals. Results of our primary analysis (i.e., the regression of memory self-appraisal accuracy on MPFC functional connectivity) were generally consistent with our hypothesis: people who were less accurate in making memory self-appraisals showed attenuated functional connectivity between the MPFC seed region and proximal areas within the MPFC (including subgenual anterior cingulate cortex), bilateral dorsolateral prefrontal cortex, bilateral caudate, and

  18. Meaning-Making in Memories: A Comparison of Memories of Death-Related and Low Point Life Experiences

    ERIC Educational Resources Information Center

    Mackay, Michael M.; Bluck, Susan

    2010-01-01

    Because of their extensive experience with death and dying, hospice volunteers may be more successful at engaging in meaning-making regarding their death-related experiences than their low point life experiences (e.g., job loss). Consequently, their memories of death-related experiences will manifest more meaning-making strategies (e.g.,…

  19. Age-related changes to the neural correlates of working memory which emerge after midlife.

    PubMed

    Macpherson, Helen N; White, David J; Ellis, Kathryn A; Stough, Con; Camfield, David; Silberstein, Richard; Pipingas, Andrew

    2014-01-01

    Previous research has indicated that the neural processes which underlie working memory change with age. Both age-related increases and decreases to cortical activity have been reported. This study investigated which stages of working memory are most vulnerable to age-related changes after midlife. To do this we examined age-differences in the 13 Hz steady state visually evoked potential (SSVEP) associated with a spatial working memory delayed response task. Participants were 130 healthy adults separated into a midlife (40-60 years) and an older group (61-82 years). Relative to the midlife group, older adults demonstrated greater bilateral frontal activity during encoding and this pattern of activity was related to better working memory performance. In contrast, evidence of age-related under activation was identified over left frontal regions during retrieval. Findings from this study suggest that after midlife, under-activation of frontal regions during retrieval contributes to age-related decline in working memory performance.

  20. Relative recency influences object-in-context memory.

    PubMed

    Tam, Shu K E; Bonardi, Charlotte; Robinson, Jasper

    2015-03-15

    In two experiments rats received training on an object-in-context (OIC) task, in which they received preexposure to object A in context x, followed by exposure to object B in context y. In a subsequent test both A and B are presented in either context x or context y. Usually more exploration is seen of the object that has not previously been paired with the test context, an effect attributed to the ability to remember where an object was encountered. However, in the typical version of this task, object A has also been encountered less recently than object B at test. This is precisely the arrangement in tests of 'relatively recency' (RR), in which more remotely presented objects are explored more than objects experienced more recently. RR could contaminate performance on the OIC task, by enhancing the OIC effect when animals are tested in context y, and masking it when the test is in context x. This possibility was examined in two experiments, and evidence for superior performance in context y was obtained. The implications of this for theoretical interpretations of recognition memory and the procedures used to explore it are discussed.

  1. Working Memory-Related Neural Activity Predicts Future Smoking Relapse

    PubMed Central

    Loughead, James; Wileyto, E Paul; Ruparel, Kosha; Falcone, Mary; Hopson, Ryan; Gur, Ruben; Lerman, Caryn

    2015-01-01

    Brief abstinence from smoking impairs cognition, particularly executive function, and this has a role in relapse to smoking. This study examined whether working memory-related brain activity predicts subsequent smoking relapse above and beyond standard clinical and behavioral measures. Eighty treatment-seeking smokers completed two functional magnetic resonance imaging sessions (smoking satiety vs 24 h abstinence challenge) during performance of a visual N-back task. Brief counseling and a short-term quit attempt followed. Relapse during the first 7 days was biochemically confirmed by the presence of the nicotine metabolite cotinine. Mean percent blood oxygen level-dependent (BOLD) signal change was extracted from a priori regions of interest: bilateral dorsolateral prefrontal cortex (DLPFC), medial frontal/cingulate gyrus, posterior cingulate cortex (PCC), and ventromedial prefrontal cortex. Signal from these brain regions and additional clinical measures were used to model outcome status, which was then validated with resampling techniques. Relapse to smoking was predicted by increased withdrawal symptoms, decreased left DLPFC and increased PCC BOLD percent signal change (abstinence vs smoking satiety). Receiver operating characteristic analysis demonstrated 81% area under the curve using these predictors, a significant improvement over the model with clinical variables only. The combination of abstinence-induced decreases in left DLPFC activation and reduced suppression of PCC may be a prognostic marker for poor outcome, specifically early smoking relapse. PMID:25469682

  2. Mechanisms of Age-Related Decline in Memory Search across the Adult Life Span

    ERIC Educational Resources Information Center

    Hills, Thomas T.; Mata, Rui; Wilke, Andreas; Samanez-Larkin, Gregory R.

    2013-01-01

    Three alternative mechanisms for age-related decline in memory search have been proposed, which result from either reduced processing speed (global slowing hypothesis), overpersistence on categories (cluster-switching hypothesis), or the inability to maintain focus on local cues related to a decline in working memory (cue-maintenance hypothesis).…

  3. Relativity of remembering: why the laws of memory vanished.

    PubMed

    Roediger, Henry L

    2008-01-01

    For 120 years, cognitive psychologists have sought general laws of learning and memory. In this review I conclude that none has stood the test of time. No empirical law withstands manipulation across the four sets of factors that Jenkins (1979) identified as critical to memory experiments: types of subjects, kinds of events to be remembered, manipulation of encoding conditions, and variations in test conditions. Another factor affecting many phenomena is whether a manipulation of conditions occurs in randomized, within-subjects designs rather than between-subjects (or within-subject, blocked) designs. The fact that simple laws do not hold reveals the complex, interactive nature of memory phenomena. Nonetheless, the science of memory is robust, with most findings easily replicated under the same conditions as originally used, but when other variables are manipulated, effects may disappear or reverse. These same points are probably true of psychological research in most, if not all, domains.

  4. Modifying memory for a museum tour in older adults: Reactivation-related updating that enhances and distorts memory is reduced in ageing.

    PubMed

    St Jacques, Peggy L; Montgomery, Daniel; Schacter, Daniel L

    2015-01-01

    Memory reactivation, the activation of a latent memory trace when we are reminded of a past experience, strengthens memory but can also contribute to distortions if new information present during reactivation is integrated with existing memory. In a previous study in young adults we found that the quality of memory reactivation, manipulated using the principle of encoding specificity and indexed by recollection ratings, modulated subsequent true and false memories for events experienced during a museum tour. Here in this study, we examined age-related changes in the quality of memory reactivation on subsequent memory. Memories of museum stops in young and older adults were reactivated and then immediately followed by the presentation of a novel lure photo from an alternate tour version (i.e., reactivation plus new information). There was an increase in subsequent true memories for reactivated targets and for subsequent false memories for lures that followed reactivated targets, when compared to baseline target and lure photos. However, the influence of reactivation on subsequent memories was reduced in older adults. These data reveal that ageing alters reactivation-related updating processes that allow memories to be strengthened and updated with new information, consequently reducing memory distortions in older adults compared to young adults.

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

    PubMed Central

    Morris, Ken A.; Gold, Paul E.

    2012-01-01

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

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

    PubMed

    Morris, Ken A; Gold, Paul E

    2013-02-01

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

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

    PubMed Central

    2013-01-01

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

  8. Death-related versus fond memories of a deceased attachment figure: examining emotional arousal.

    PubMed

    Rochman, Daniel

    2013-09-01

    Grieving is infused by memories and emotions. In this study, bereaved participants recalled either death-related or fond memories of their loved ones. Their emotional arousal was examined via physiologic and voice analytic measures. Both death-related and fond memories generated an acoustic profile indicative of sadness (reflected by voice quality related parameters). Death-related memories, moreover, lead to bodily tension reflected by increased diastolic blood pressure levels and mean fundamental frequency of the voice signal. Consistent with the continuing bond and attachment perspectives, "death," a reminder of the irrevocability of the loss, induced distress/anxiety. In contrast, fond memories lead to more moderate, melancholic sadness, presumably because of their association with the soothing qualities of the attachment figure.

  9. BAIAP2 is related to emotional modulation of human memory strength.

    PubMed

    Luksys, Gediminas; Ackermann, Sandra; Coynel, David; Fastenrath, Matthias; Gschwind, Leo; Heck, Angela; Rasch, Bjoern; Spalek, Klara; Vogler, Christian; Papassotiropoulos, Andreas; de Quervain, Dominique

    2014-01-01

    Memory performance is the result of many distinct mental processes, such as memory encoding, forgetting, and modulation of memory strength by emotional arousal. These processes, which are subserved by partly distinct molecular profiles, are not always amenable to direct observation. Therefore, computational models can be used to make inferences about specific mental processes and to study their genetic underpinnings. Here we combined a computational model-based analysis of memory-related processes with high density genetic information derived from a genome-wide study in healthy young adults. After identifying the best-fitting model for a verbal memory task and estimating the best-fitting individual cognitive parameters, we found a common variant in the gene encoding the brain-specific angiogenesis inhibitor 1-associated protein 2 (BAIAP2) that was related to the model parameter reflecting modulation of verbal memory strength by negative valence. We also observed an association between the same genetic variant and a similar emotional modulation phenotype in a different population performing a picture memory task. Furthermore, using functional neuroimaging we found robust genotype-dependent differences in activity of the parahippocampal cortex that were specifically related to successful memory encoding of negative versus neutral information. Finally, we analyzed cortical gene expression data of 193 deceased subjects and detected significant BAIAP2 genotype-dependent differences in BAIAP2 mRNA levels. Our findings suggest that model-based dissociation of specific cognitive parameters can improve the understanding of genetic underpinnings of human learning and memory.

  10. Effects of working memory contents and perceptual load on distractor processing: When a response-related distractor is held in working memory.

    PubMed

    Koshino, Hideya

    2017-01-01

    Working memory and attention are closely related. Recent research has shown that working memory can be viewed as internally directed attention. Working memory can affect attention in at least two ways. One is the effect of working memory load on attention, and the other is the effect of working memory contents on attention. In the present study, an interaction between working memory contents and perceptual load in distractor processing was investigated. Participants performed a perceptual load task in a standard form in one condition (Single task). In the other condition, a response-related distractor was maintained in working memory, rather than presented in the same stimulus display as a target (Dual task). For the Dual task condition, a significant compatibility effect was found under high perceptual load; however, there was no compatibility effect under low perceptual load. These results suggest that the way the contents of working memory affect visual search depends on perceptual load.

  11. Intelligence as it relates to conscious and unconscious memory influences.

    PubMed

    Joordens, Steve; Walsh, Darlene; Mantonakis, Antonia

    2013-09-01

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

  12. Neural similarity between encoding and retrieval is related to memory via hippocampal interactions.

    PubMed

    Ritchey, Maureen; Wing, Erik A; LaBar, Kevin S; Cabeza, Roberto

    2013-12-01

    A fundamental principle in memory research is that memory is a function of the similarity between encoding and retrieval operations. Consistent with this principle, many neurobiological models of declarative memory assume that memory traces are stored in cortical regions, and the hippocampus facilitates the reactivation of these traces during retrieval. The present investigation tested the novel prediction that encoding-retrieval similarity can be observed and related to memory at the level of individual items. Multivariate representational similarity analysis was applied to functional magnetic resonance imaging data collected during encoding and retrieval of emotional and neutral scenes. Memory success tracked fluctuations in encoding-retrieval similarity across frontal and posterior cortices. Importantly, memory effects in posterior regions reflected increased similarity between item-specific representations during successful recognition. Mediation analyses revealed that the hippocampus mediated the link between cortical similarity and memory success, providing crucial evidence for hippocampal-cortical interactions during retrieval. Finally, because emotional arousal is known to modulate both perceptual and memory processes, similarity effects were compared for emotional and neutral scenes. Emotional arousal was associated with enhanced similarity between encoding and retrieval patterns. These findings speak to the promise of pattern similarity measures for evaluating memory representations and hippocampal-cortical interactions.

  13. Drosophila as a novel animal model for studying the genetics of age-related memory impairment.

    PubMed

    Saitoe, Minoru; Horiuchi, Junjiro; Tamura, Takuya; Ito, Naomi

    2005-01-01

    Understanding the molecular mechanisms underlying age-related memory impairment (AMI) is important not only from a scientific viewpoint but also for the development of therapeutics that may eventually lead to the development of drugs to combat memory loss. AMI has been generally considered to be an overall or nonspecific decay of memory processes that results from dysfunction of neural networks. However, behavioral genetics to test this hypothesis have not been performed previously, due, in part, to the long lifespan of animal models. Using Drosophila, the first extensive behavioral-genetic characterization of AMI has been carried out. In Drosophila, memory acquired after a single olfactory conditioning paradigm has three distinct phases: short-term memory (STM), middle-term memory (MTM), and longer-lasting anesthesia-resistant memory (ARM). Significantly, AMI results from the specific decay of only one memory component, amnesiac-dependent MTM, and not other components. Since amnesiac encodes peptides that enhance adenylyl cyclase activity, these studies suggest the importance of the cAMP signaling pathway in AMI in Drosophila, a finding consistent with several models of AMI in mammals. Although many advances have been made in the study of pathways involved in aging, much remains to be elucidated on how these pathways affect memory formation to cause AMI. Due to its short lifespan, powerful genetics, and well-characterized and conserved pathways involved in memory and lifespan, Drosophila will be a useful model system for studying the molecular mechanisms underlying this process.

  14. Central Adiposity is Negatively Associated with Hippocampal-Dependent Relational Memory among Overweight and Obese Children

    PubMed Central

    Khan, Naiman A.; Baym, Carol L.; Monti, Jim M.; Raine, Lauren B.; Drollette, Eric S.; Scudder, Mark R.; Moore, R. Davis; Kramer, Arthur F.; Hillman, Charles H.; Cohen, Neal J.

    2014-01-01

    Objective To assess associations between adiposity and hippocampal-dependent and hippocampal-independent memory forms among prepubertal children. Study design Prepubertal children (7–9-year-olds, n = 126), classified as non-overweight (<85th %tile BMI-for-age [n = 73]) or overweight/obese (≥85th %tile BMI-for-age [n = 53]), completed relational (hippocampal-dependent) and item (hippocampal-independent) memory tasks, and performance was assessed with both direct (behavioral accuracy) and indirect (preferential disproportionate viewing [PDV]) measures. Adiposity (%whole body fat mass, subcutaneous abdominal adipose tissue, visceral adipose tissue, and total abdominal adipose tissue) was assessed using DXA. Backward regressions identified significant (P <0.05) predictive models of memory performance. Covariates included age, sex, pubertal timing, socioeconomic status, IQ, oxygen consumption (VO2max), and body mass index (BMI) z-score. Results Among overweight/obese children, total abdominal adipose tissue was a significant negative predictor of relational memory behavioral accuracy, and pubertal timing together with socioeconomic status jointly predicted the PDV measure of relational memory. In contrast, among non-overweight children, male sex predicted item memory behavioral accuracy, and a model consisting of socioeconomic status and BMI z-score jointly predicted the PDV measure of relational memory. Conclusions Regional, and not whole body, fat deposition was selectively and negatively associated with hippocampal-dependent relational memory among overweight/obese prepubertal children. PMID:25454939

  15. Relational processing and working memory capacity in comprehension of relative clause sentences.

    PubMed

    Andrews, Glenda; Birney, Damian; Halford, Graeme S

    2006-09-01

    Previous research has indicated that the cognitive load imposed by tasks in various content domains increases with the complexity of the relational information processed. Sentence comprehension entails processing noun-verb relations to determine who did what to whom. The difficulty of object-extracted relative clause sentences might stem from the complex noun-verb relations they entail. Across three studies, participants read 16 types of object- and subject-extracted relative clause sentences at their own pace and then responded to a comprehension question for each sentence. Relational processing was assessed using a premise integration task or a Latin square task. These tasks predicted comprehension of object-relatives before and after controlling for subject-relatives. Working memory (WM) capacity was assessed using reading span or forward and backward digit span tests. WM tasks predicted comprehension of object-relatives before but not after controlling for subject-relatives. Comprehension of object-relatives relied more heavily on a domain-general capacity to process complex relations than on WM capacity.

  16. Exploratory study of the relations between spatial ability and drawing from memory.

    PubMed

    Czarnolewski, Mark Y; Eliot, John

    2012-04-01

    Test scores of 119 students, attending either a public four-year college or a technical school, were related to their proportionality and detail drawing scores on the Memory for Designs Test. In regression models, the ETS Maze Tracing, Eliot-Price Mental Rotations, and Bender-Gestalt tests were consistent predictors of proportionality scores, with the latter two tests uniquely related to these. The ETS Shapes Memory Test and the Form Board Test were the strongest predictors for detail accuracy scores. The Shapes test predicted proportionality when the CTY Visual Memory Test BB was excluded. The models then provided support for the hypothesis that drawing designs from memory, a critical skill in drawing, regardless of whether one focuses on accuracy for proportionality scores or for detail scores, is jointly related to the measures of recognition, production, and traditional spatial ability measures. This study identified multifaceted skills in drawing from memory.

  17. Age-related memory impairments due to reduced blood glucose responses to epinephrine.

    PubMed

    Morris, Ken A; Chang, Qing; Mohler, Eric G; Gold, Paul E

    2010-12-01

    Increases in blood glucose levels are an important component of the mechanisms by which epinephrine enhances memory formation. The present experiments addressed the hypothesis that a dysfunction in the blood glucose response to circulating epinephrine contributes to age-related memory impairments. Doses of epinephrine and glucagon that significantly increased blood glucose levels in young adult rats were far less effective at doing so in 2-year-old rats. In young rats, epinephrine and glucose were about equally effective in enhancing memory and in prolonging post-training release of acetylcholine in the hippocampus. However, glucose was more effective than epinephrine in enhancing both memory and acetylcholine release in aged rats. These results suggest that an uncoupling between circulating epinephrine and glucose levels in old rats may lead to an age-related reduction in the provision of glucose to the brain during training. This in turn may contribute to age-related changes in memory and neural plasticity.

  18. An overview of advanced nonvolatile memory technologies

    SciTech Connect

    Dressendorfer, P.V.

    1991-01-01

    This report is an overview of advanced nonvolatile memory technologies. The memory technologies discussed are: floating gate nonvolatile memory technologies; SNOS nonvolatile technology; ferroelectric technology; and thin film magnetic memories.

  19. Developmental Changes in Memory-Related Linguistic Skills and Their Relationship to Episodic Recall in Children

    PubMed Central

    Uehara, Izumi

    2015-01-01

    This longitudinal study of nine children examined two issues concerning infantile amnesia: the time at which memories for events experienced before the age of 3–4 years disappear from consciousness and whether this timing of memory loss is related to the development of specific aspects of episodic and autobiographical memory. This study followed children from infancy to early childhood and examined the central role of three verbal–cognitive milestones related to autobiographical memory: the age at which children begin to report autobiographical memories using the past tense (Milestone 1); the age at which they begin to verbally acknowledge past events (Milestone 2); and the age at which they begin to spontaneously use memory-related verbs (Milestone 3). As expected, memories of events that occurred before 3–4 years of age were affected by infantile amnesia. Achievement of these milestones followed almost the same developmental progression: Milestone 1 (1 year; 10 months (1;10) to 3 years; 4 months (3;4)) was followed by Milestones 2 (3;1 to 4;0) and 3 (3;5 to 4;4). Milestone 2 was typically related to the onset of infantile amnesia, whereas Milestone 1 occurred during the period for which the children became amnesic as they aged. These data suggest that linguistic meta-cognitive awareness of personal memory is the key feature in infantile amnesia. PMID:26331479

  20. 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…

  1. Event related potentials and EEG components in a semantic memory search task.

    PubMed

    Mecklinger, A; Kramer, A F; Strayer, D L

    1992-01-01

    This study examined the effects of memory search and related processes on both time and frequency domain components of electroencephalographic activity. More specifically, we were interested in the relationship between EEG and event-related potential (ERP) components as a function of memory load and response type. Subjects performed a semantic memory search task in which they matched word probes to category labels. Consistent with previous studies, reaction time increased and accuracy decreased with increasing memory loads. A negative component of the ERP (N400) was found to reflect semantic mismatch: N400s were larger for the nontargets than for the targets. Two ERP components were found to be reciprocally related to memory load. P300 decreased and Negative Slow Wave increased in amplitude with increases in the size of the memory set. These two ERP components were reflected by different components in a Principal Components Analysis. The power in the theta band (5-7 Hz) also increased as a function of memory load and appears to be functionally and topographically related to the Negative Slow Wave in the ERP. It is argued that both measures are jointly determined and reflect the difficulty of the conceptual operations during memory search.

  2. Developmental Changes in Memory Encoding: Insights from Event-Related Potentials

    ERIC Educational Resources Information Center

    Rollins, Leslie; Riggins, Tracy

    2013-01-01

    The aim of the present study was to investigate developmental changes in encoding processes between 6-year-old children and adults using event-related potentials (ERPs). Although episodic memory ("EM") effects have been reported in both children and adults at retrieval and subsequent memory effects have been established in adults, no…

  3. The Relation between Mathematics and Working Memory in Young Children with Fetal Alcohol Spectrum Disorders

    ERIC Educational Resources Information Center

    Rasmussen, Carmen; Bisanz, Jeffrey

    2011-01-01

    The goal of this study was to examine the relation between mathematics and working memory in young children with Fetal Alcohol Spectrum Disorders (FASD). Children with FASD and comparison children (4 to 6 years old) completed standardized tests of mathematics and working memory. Children with FASD showed impairments on mathematics (applied…

  4. Working Memory Effects in the L2 Processing of Ambiguous Relative Clauses

    ERIC Educational Resources Information Center

    Hopp, Holger

    2014-01-01

    This article investigates whether and how L2 sentence processing is affected by memory constraints that force serial parsing. Monitoring eye movements, we test effects of working memory on L2 relative-clause attachment preferences in a sample of 75 late-adult German learners of English and 25 native English controls. Mixed linear regression…

  5. Working memory contributions to relative clause attachment processing: a hierarchical linear modeling analysis.

    PubMed

    Traxler, Matthew J

    2007-07-01

    An eye-movement-monitoring experiment tested readers' responses to sentences containing relative clauses that could be attached to one or both of two preceding nouns. Previous experiments with such sentences have indicated that globally ambiguous relative clauses are processed more quickly than are determinately attached relative clauses. Central to the present research, a recent study (Swets, Desmet, Hambrick, & Ferreira, 2007) showed that offline preferences for such sentences differ as a function of working memory capacity. Specifically, both English and Dutch participants' preference for the second of two nouns as the host for the relative clause increased as their working memory capacity increased. In the present study, readers' working memory capacity was measured, and eye movements were monitored. Hierarchical linear modeling was used to determine whether working memory capacity moderated readers' online processing performance. The modeling indicated that determinately attached sentences were harder to process than globally ambiguous sentences, that working memory did not affect processing of the relative clause itself, but that working memory did moderate how easy it was to integrate the relative clause with the preceding sentence context. Specifically, in contrast with the offline results from Swets and colleagues' study, readers with higher working memory capacity were more likely to prefer the first noun over the second noun as the host for the relative clause.

  6. Memory and negative-resistance effects in a strained metal-gate high-k n-type field-effect-transistor from 375 K down to 77 K

    NASA Astrophysics Data System (ADS)

    Gutiérrez-D, E. A.; Vega-G, V. H.; García-R, P. J.; Huerta-G, O. V.

    2016-12-01

    We introduce an experimental alternative way of looking into the charging and discharging mechanism inside a high-k stacked oxide of a metal-gate strained n-type Field-Effect-Transistor (nFET). This alternative way reproduces a memory and negative resistance effect by biasing the nFET device in a non-conventional way. This is achieved by forward-biasing the drain-bulk junction and by setting the gate electrode in a high-impedance mode. The produced negative resistance effect (NRE) has a controllable peak-to-valley current ratio (PVCR) that goes from about 3.0 up to a value of 5.5 at room temperature. The PVCR increases up to 8.35 at T = 225 K and reduces to 2.84 at T = 375 K in a linear trend. The memory effect is observed when the drain-bulk junction voltage is swept from low to high values and back from high to low values. From low to high forward drain-bulk bias the NRE shows up and vanishes when coming back from high to low forward drain-bulk bias. The NRE and memory effects are attributed to a coupled-gate oxide charging/discharging mechanism with an induced bipolar transistor action in the channel of the FET.

  7. Nonvolatile floating gate memory containing AgInSbTe-SiO2 nanocomposite layer and capping the HfO2/SiO2 composite blocking oxide layer.

    PubMed

    Chiang, Kuo-Chang; Hsieh, Tsung-Eong

    2012-06-08

    An extremely large memory window shift of about 30.7 V and high charge storage density =2.3 × 10(13) cm(-2) at ± 23 V gate voltage sweep were achieved in the nonvolatile floating gate memory (NFGM) device containing the AgInSbTe (AIST)-SiO(2) nanocomposite as the charge trap layer and HfO(2)/SiO(2) as the blocking oxide layer. Due to the deep trap sites formed by high-density AIST nanocrystals (NCs) in the nanocomposite matrix and the high-barrier-height feature of the composite blocking oxide layer, a good retention property of the device with a charge loss of about 16.1% at ± 15 V gate voltage stress for 10(4) s at the test temperature of 85 °C was observed. In addition to inhibiting the Hf diffusion into the programming layer, incorporation of the SiO(2) layer prepared by plasma-enhanced chemical vapor deposition in the sample provided a good Coulomb blockade effect and allowed significant charge storage in AIST NCs. Analytical results demonstrated the feasibility of an AIST-SiO(2) nanocomposite layer in memory device fabrication with a simplified processing method and post-annealing at a comparatively low temperature of 400 °C in comparison with previous NC-based NFGM studies.

  8. Relation between Intelligence and Short-Term Memory

    ERIC Educational Resources Information Center

    Cohen, Ronald L.; Sandberg, Tor

    1977-01-01

    Intelligence and short-term memory correlations in children were measured using probed serial recall of supraspan digit lists. Results showed the predictive power of intelligence to range from a maximum in the case of recall for recency items to practically zero in the case of primacy items. (Author/MV)

  9. Mitigation of cache memory using an embedded hard-core PPC440 processor in a Virtex-5 Field Programmable Gate Array.

    SciTech Connect

    Learn, Mark Walter

    2010-02-01

    Sandia National Laboratories is currently developing new processing and data communication architectures for use in future satellite payloads. These architectures will leverage the flexibility and performance of state-of-the-art static-random-access-memory-based Field Programmable Gate Arrays (FPGAs). One such FPGA is the radiation-hardened version of the Virtex-5 being developed by Xilinx. However, not all features of this FPGA are being radiation-hardened by design and could still be susceptible to on-orbit upsets. One such feature is the embedded hard-core PPC440 processor. Since this processor is implemented in the FPGA as a hard-core, traditional mitigation approaches such as Triple Modular Redundancy (TMR) are not available to improve the processor's on-orbit reliability. The goal of this work is to investigate techniques that can help mitigate the embedded hard-core PPC440 processor within the Virtex-5 FPGA other than TMR. Implementing various mitigation schemes reliably within the PPC440 offers a powerful reconfigurable computing resource to these node-based processing architectures. This document summarizes the work done on the cache mitigation scheme for the embedded hard-core PPC440 processor within the Virtex-5 FPGAs, and describes in detail the design of the cache mitigation scheme and the testing conducted at the radiation effects facility on the Texas A&M campus.

  10. Declarative memory and skill-related knowledge: Evidence from a case study of amnesia and implications for theories of memory.

    PubMed

    Gregory, Emma; McCloskey, Michael; Ovans, Zoe; Landau, Barbara

    2016-01-01

    Theoretical and empirical studies of memory have long been framed by a distinction between declarative and non-declarative memory. We question the sharpness of the distinction by reporting evidence from amnesic L.S.J., who despite retrograde memory losses in declarative knowledge domains, shows sparing of declarative knowledge related to premorbid skill (e.g., playing an instrument). We previously showed that L.S.J. had severe losses of retrograde declarative knowledge across areas of premorbid expertise (e.g., artists of famous works) and everyday knowledge (e.g., company names for logos). Here we present evidence that L.S.J. has sparing of what we call skill-related declarative knowledge, in four domains in which she had premorbid skill (art, music, aviation, driving). L.S.J.'s pattern of loss and sparing raises questions about the strict separation between classically-defined memory types and aligns with a recent proposal by Stanley and Krakauer [2013. Motor skill depends on knowledge of facts. Frontiers in Human Neuroscience, 7,1-11].

  11. Sleep-related memory consolidation in depression: an emerging field of research.

    PubMed

    Hornung, Orla Patricia; Regen, Francesca; Danker-Hopfe, Heidi; Heuser, Isabella; Anghelescu, Ion

    2008-01-01

    Sleep-related memory consolidation has received increasing attention in recent years. Because previous research has focused on healthy young adults, only very few studies have been conducted in patients with psychiatric disorders so far. The investigation of sleep-related memory consolidation in depression offers a wide range of future research opportunities and can therefore be regarded as an emerging field of research. This article gives a short overview of current knowledge of sleep-related memory consolidation in healthy young adults and builds a bridge to psychiatry and depression, where further research is urgently needed.

  12. Neural correlates of opposing effects of emotional distraction on working memory and episodic memory: an event-related FMRI investigation.

    PubMed

    Dolcos, Florin; Iordan, Alexandru D; Kragel, James; Stokes, Jared; Campbell, Ryan; McCarthy, Gregory; Cabeza, Roberto

    2013-01-01

    A fundamental question in the emotional memory literature is why emotion enhances memory in some conditions but disrupts memory in other conditions. For example, separate studies have shown that emotional stimuli tend to be better remembered in long-term episodic memory (EM), whereas emotional distracters tend to impair working memory (WM) maintenance. The first goal of this study was to directly compare the neural correlates of EM enhancement (EME) and WM impairing (WMI) effects, and the second goal was to explore individual differences in these mechanisms. During event-related functional magnetic resonance imaging (fMRI), participants maintained faces in WM while being distracted by emotional or neutral pictures presented during the delay period. EM for the distracting pictures was tested after scanning and was used to identify successful encoding activity for the picture distracters. The first goal yielded two findings: (1) emotional pictures that disrupted face WM but enhanced subsequent EM were associated with increased amygdala (AMY) and hippocampal activity (ventral system) coupled with reduced dorsolateral PFC (dlPFC) activity (dorsal system); (2) trials in which emotion enhanced EM without disrupting WM were associated with increased ventrolateral PFC activity. The ventral-dorsal switch can explain EME and WMI, while the ventrolateral PFC effect suggests a coping mechanism. The second goal yielded two additional findings: (3) participants who were more susceptible to WMI showed greater amygdala increases and PFC reductions; (4) AMY activity increased and dlPFC activity decreased with measures of attentional impulsivity. Taken together, these results clarify the mechanisms linking the enhancing and impairing effects of emotion on memory, and provide insights into the role of individual differences in the impact of emotional distraction.

  13. Age-related decline of precision and binding in visual working memory.

    PubMed

    Peich, Muy-Cheng; Husain, Masud; Bays, Paul M

    2013-09-01

    Working memory declines with normal aging, but the nature of this impairment is debated. Studies based on detecting changes to arrays of visual objects have identified two possible components to age-related decline: a reduction in the number of items that can be stored, or a deficit in maintaining the associations (bindings) between individual object features. However, some investigations have reported intact binding with aging, and specific deficits arising only in Alzheimer's disease. Here, using a recently developed continuous measure of recall fidelity, we tested the precision with which adults of different ages could reproduce from memory the orientation and color of a probed array item. The results reveal a further component of cognitive decline: an age-related decrease in the resolution with which visual information can be maintained in working memory. This increase in recall variability with age was strongest under conditions of greater memory load. Moreover, analysis of the distribution of errors revealed that older participants were more likely to incorrectly report one of the unprobed items in memory, consistent with an age-related increase in misbinding. These results indicate a systematic decline with age in working memory resources that can be recruited to store visual information. The paradigm presented here provides a sensitive index of both memory resolution and feature binding, with the potential for assessing their modulation by interventions. The findings have implications for understanding the mechanisms underpinning working memory deficits in both health and disease.

  14. The Construction of Semantic Memory: Grammar-Based Representations Learned from Relational Episodic Information

    PubMed Central

    Battaglia, Francesco P.; Pennartz, Cyriel M. A.

    2011-01-01

    After acquisition, memories underlie a process of consolidation, making them more resistant to interference and brain injury. Memory consolidation involves systems-level interactions, most importantly between the hippocampus and associated structures, which takes part in the initial encoding of memory, and the neocortex, which supports long-term storage. This dichotomy parallels the contrast between episodic memory (tied to the hippocampal formation), collecting an autobiographical stream of experiences, and semantic memory, a repertoire of facts and statistical regularities about the world, involving the neocortex at large. Experimental evidence points to a gradual transformation of memories, following encoding, from an episodic to a semantic character. This may require an exchange of information between different memory modules during inactive periods. We propose a theory for such interactions and for the formation of semantic memory, in which episodic memory is encoded as relational data. Semantic memory is modeled as a modified stochastic grammar, which learns to parse episodic configurations expressed as an association matrix. The grammar produces tree-like representations of episodes, describing the relationships between its main constituents at multiple levels of categorization, based on its current knowledge of world regularities. These regularities are learned by the grammar from episodic memory information, through an expectation-maximization procedure, analogous to the inside–outside algorithm for stochastic context-free grammars. We propose that a Monte-Carlo sampling version of this algorithm can be mapped on the dynamics of “sleep replay” of previously acquired information in the hippocampus and neocortex. We propose that the model can reproduce several properties of semantic memory such as decontextualization, top-down processing, and creation of schemata. PMID:21887143

  15. Electrically programmable-erasable In-Ga-Zn-O thin-film transistor memory with atomic-layer-deposited Al2O3/Pt nanocrystals/Al2O3 gate stack

    NASA Astrophysics Data System (ADS)

    Qian, Shi-Bing; Zhang, Wen-Peng; Liu, Wen-Jun; Ding, Shi-Jin

    2015-12-01

    Amorphous indium-gallium-zinc oxide (a-IGZO) thin-film transistor (TFT) memory is very promising for transparent and flexible system-on-panel displays; however, electrical erasability has always been a severe challenge for this memory. In this article, we demonstrated successfully an electrically programmable-erasable memory with atomic-layer-deposited Al2O3/Pt nanocrystals/Al2O3 gate stack under a maximal processing temperature of 300 oC. As the programming voltage was enhanced from 14 to 19 V for a constant pulse of 0.2 ms, the threshold voltage shift increased significantly from 0.89 to 4.67 V. When the programmed device was subjected to an appropriate pulse under negative gate bias, it could return to the original state with a superior erasing efficiency. The above phenomena could be attributed to Fowler-Nordheim tunnelling of electrons from the IGZO channel to the Pt nanocrystals during programming, and inverse tunnelling of the trapped electrons during erasing. In terms of 0.2-ms programming at 16 V and 350-ms erasing at -17 V, a large memory window of 3.03 V was achieved successfully. Furthermore, the memory exhibited stable repeated programming/erasing (P/E) characteristics and good data retention, i.e., for 2-ms programming at 14 V and 250-ms erasing at -14 V, a memory window of 2.08 V was still maintained after 103 P/E cycles, and a memory window of 1.1 V was retained after 105 s retention time.

  16. Electrically programmable-erasable In-Ga-Zn-O thin-film transistor memory with atomic-layer-deposited Al{sub 2}O{sub 3}/Pt nanocrystals/Al{sub 2}O{sub 3} gate stack

    SciTech Connect

    Qian, Shi-Bing; Zhang, Wen-Peng; Liu, Wen-Jun; Ding, Shi-Jin

    2015-12-15

    Amorphous indium-gallium-zinc oxide (a-IGZO) thin-film transistor (TFT) memory is very promising for transparent and flexible system-on-panel displays; however, electrical erasability has always been a severe challenge for this memory. In this article, we demonstrated successfully an electrically programmable-erasable memory with atomic-layer-deposited Al{sub 2}O{sub 3}/Pt nanocrystals/Al{sub 2}O{sub 3} gate stack under a maximal processing temperature of 300 {sup o}C. As the programming voltage was enhanced from 14 to 19 V for a constant pulse of 0.2 ms, the threshold voltage shift increased significantly from 0.89 to 4.67 V. When the programmed device was subjected to an appropriate pulse under negative gate bias, it could return to the original state with a superior erasing efficiency. The above phenomena could be attributed to Fowler-Nordheim tunnelling of electrons from the IGZO channel to the Pt nanocrystals during programming, and inverse tunnelling of the trapped electrons during erasing. In terms of 0.2-ms programming at 16 V and 350-ms erasing at −17 V, a large memory window of 3.03 V was achieved successfully. Furthermore, the memory exhibited stable repeated programming/erasing (P/E) characteristics and good data retention, i.e., for 2-ms programming at 14 V and 250-ms erasing at −14 V, a memory window of 2.08 V was still maintained after 10{sup 3} P/E cycles, and a memory window of 1.1 V was retained after 10{sup 5} s retention time.

  17. Short-term retention of relational memory in amnesia revisited: accurate performance depends on hippocampal integrity

    PubMed Central

    Yee, Lydia T. S.; Hannula, Deborah E.; Tranel, Daniel; Cohen, Neal J.

    2014-01-01

    Traditionally, it has been proposed that the hippocampus and adjacent medial temporal lobe cortical structures are selectively critical for long-term declarative memory, which entails memory for inter-item and item-context relationships. Whether the hippocampus might also contribute to short-term retention of relational memory representations has remained controversial. In two experiments, we revisit this question by testing memory for relationships among items embedded in scenes using a standard working memory trial structure in which a sample stimulus is followed by a brief delay and the corresponding test stimulus. In each experimental block, eight trials using different exemplars of the same scene were presented. The exemplars contained the same items but with different spatial relationships among them. By repeating the pictures across trials, any potential contributions of item or scene memory to performance were minimized, and relational memory could be assessed more directly than has been done previously. When test displays were presented, participants indicated whether any of the item-location relationships had changed. Then, regardless of their responses (and whether any item did change its location), participants indicated on a forced-choice test, which item might have moved, guessing if necessary. Amnesic patients were impaired on the change detection test, and were frequently unable to specify the change after having reported correctly that a change had taken place. Comparison participants, by contrast, frequently identified the change even when they failed to report the mismatch, an outcome that speaks to the sensitivity of the change specification measure. These results confirm past reports of hippocampal contributions to short-term retention of relational memory representations, and suggest that the role of the hippocampus in memory has more to do with relational memory requirements than the length of a retention interval. PMID:24478681

  18. Short-term retention of relational memory in amnesia revisited: accurate performance depends on hippocampal integrity.

    PubMed

    Yee, Lydia T S; Hannula, Deborah E; Tranel, Daniel; Cohen, Neal J

    2014-01-01

    Traditionally, it has been proposed that the hippocampus and adjacent medial temporal lobe cortical structures are selectively critical for long-term declarative memory, which entails memory for inter-item and item-context relationships. Whether the hippocampus might also contribute to short-term retention of relational memory representations has remained controversial. In two experiments, we revisit this question by testing memory for relationships among items embedded in scenes using a standard working memory trial structure in which a sample stimulus is followed by a brief delay and the corresponding test stimulus. In each experimental block, eight trials using different exemplars of the same scene were presented. The exemplars contained the same items but with different spatial relationships among them. By repeating the pictures across trials, any potential contributions of item or scene memory to performance were minimized, and relational memory could be assessed more directly than has been done previously. When test displays were presented, participants indicated whether any of the item-location relationships had changed. Then, regardless of their responses (and whether any item did change its location), participants indicated on a forced-choice test, which item might have moved, guessing if necessary. Amnesic patients were impaired on the change detection test, and were frequently unable to specify the change after having reported correctly that a change had taken place. Comparison participants, by contrast, frequently identified the change even when they failed to report the mismatch, an outcome that speaks to the sensitivity of the change specification measure. These results confirm past reports of hippocampal contributions to short-term retention of relational memory representations, and suggest that the role of the hippocampus in memory has more to do with relational memory requirements than the length of a retention interval.

  19. Insightful Imagery is Related to Working Memory Updating

    PubMed Central

    Nęcka, Edward; Żak, Piotr; Gruszka, Aleksandra

    2016-01-01

    Available body of evidence concerning the relationship between insight problem solving and working memory (WM) is ambiguous. Several authors propose that restructuring of the problem representation requires controlled search processes, which needs planning and involvement of WM. Other researchers suggest that the restructuring is achieved through the automatic spread of activation in long-term memory, assigning a limited role to WM capacity. In the present study we examined the correlations between insight problem solving performance and measures of WM updating function (n-back task), including general intelligence (as measured by Raven’s Advanced Progressive Matrices). The results revealed that updating function shared up to 30% of variance with the insight problem task performance, even when the influence of general mental ability was controlled for. These results suggest that insight problem solving is constrained by individual ability to update the content of WM. PMID:26973549

  20. Memories.

    ERIC Educational Resources Information Center

    Brand, Judith, Ed.

    1998-01-01

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

  1. Individual Differences in Algebraic Cognition: Relation to the Approximate Number and Sematic Memory Systems

    PubMed Central

    Geary, David C.; Hoard, Mary K.; Nugent, Lara; Rouder, Jeffrey N.

    2015-01-01

    The relation between performance on measures of algebraic cognition and acuity of the approximate number system (ANS) and memory for addition facts was assessed for 171 (92 girls) 9th graders, controlling parental education, sex, reading achievement, speed of numeral processing, fluency of symbolic number processing, intelligence, and the central executive component of working memory. The algebraic tasks assessed accuracy in placing x,y pairs in the coordinate plane, speed and accuracy of expression evaluation, and schema memory for algebra equations. ANS acuity was related to accuracy of placements in the coordinate plane and expression evaluation, but not schema memory. Frequency of fact-retrieval errors was related to schema memory but not coordinate plane or expression evaluation accuracy. The results suggest the ANS may contribute to or is influenced by spatial-numerical and numerical only quantity judgments in algebraic contexts, whereas difficulties in committing addition facts to long-term memory may presage slow formation of memories for the basic structure of algebra equations. More generally, the results suggest different brain and cognitive systems are engaged during the learning of different components of algebraic competence, controlling demographic and domain general abilities. PMID:26255604

  2. Individual differences in algebraic cognition: Relation to the approximate number and semantic memory systems.

    PubMed

    Geary, David C; Hoard, Mary K; Nugent, Lara; Rouder, Jeffrey N

    2015-12-01

    The relation between performance on measures of algebraic cognition and acuity of the approximate number system (ANS) and memory for addition facts was assessed for 171 ninth graders (92 girls) while controlling for parental education, sex, reading achievement, speed of numeral processing, fluency of symbolic number processing, intelligence, and the central executive component of working memory. The algebraic tasks assessed accuracy in placing x,y pairs in the coordinate plane, speed and accuracy of expression evaluation, and schema memory for algebra equations. ANS acuity was related to accuracy of placements in the coordinate plane and expression evaluation but not to schema memory. Frequency of fact retrieval errors was related to schema memory but not to coordinate plane or expression evaluation accuracy. The results suggest that the ANS may contribute to or be influenced by spatial-numerical and numerical-only quantity judgments in algebraic contexts, whereas difficulties in committing addition facts to long-term memory may presage slow formation of memories for the basic structure of algebra equations. More generally, the results suggest that different brain and cognitive systems are engaged during the learning of different components of algebraic competence while controlling for demographic and domain general abilities.

  3. Selectivity of verbal memory deficit in schizophrenic patients and their relatives.

    PubMed

    Toulopoulou, Timothea; Morris, Robin G; Rabe-Hesketh, Sophia; Murray, Robin M

    2003-01-01

    Some of the relatives of people with schizophrenia show impairments of memory and executive function. It is not known, however, whether within these domains there is a class of processes that is especially impaired. Seventy schizophrenic or schizoaffective patients, 115 of their relatives and 66 normal controls underwent a series of assessments evaluating modality specific recall/learning, and aspects of executive functioning, including, planning ability, spatial working memory, strategy formation and rapid mental flexibility. The pattern of performance across cognitive processes was assessed using z-scores that allow direct comparison between tests with different raw score metrics. Selectivity of deficit was evaluated by subtracting the z-score of each cognitive process from the mean of the z-scores of those remaining. Patients performed out worse than controls on most measures, with verbal immediate recall and visual memory/learning the most impaired. Their relatives showed lower scores than controls on verbal and visual memory/learning and strategy formation; verbal memory and strategy formation remained impaired after eliminating those relatives with a psychiatric diagnosis. Consistent with the findings in their schizophrenic kin, healthy relatives also showed disproportionate impairments in verbal immediate recall. Our finding of a selective deficit in verbal memory among relatives suggests that such impairment constitutes a familial, probably genetic, risk factor for schizophrenia.

  4. Effects of frequent marijuana use on memory-related regional cerebral blood flow.

    PubMed

    Block, Robert I; O'Leary, Daniel S; Hichwa, Richard D; Augustinack, Jean C; Boles Ponto, Laura L; Ghoneim, M M; Arndt, Stephan; Hurtig, Richard R; Watkins, G Leonard; Hall, James A; Nathan, Peter E; Andreasen, Nancy C

    2002-05-01

    It is uncertain whether frequent marijuana use adversely affects human brain function. Using positron emission tomography (PET), memory-related regional cerebral blood flow was compared in frequent marijuana users and nonusing control subjects after 26+ h of monitored abstention. Memory-related blood flow in marijuana users, relative to control subjects, showed decreases in prefrontal cortex, increases in memory-relevant regions of cerebellum, and altered lateralization in hippocampus. Marijuana users differed most in brain activity related to episodic memory encoding. In learning a word list to criterion over multiple trials, marijuana users, relative to control subjects, required means of 2.7 more presentations during initial learning and 3.1 more presentations during subsequent relearning. In single-trial recall, marijuana users appeared to rely more on short-term memory, recalling 23% more than control subjects from the end of a list, but 19% less from the middle. These findings indicate altered memory-related brain function in marijuana users.

  5. Evaluation of clinical IMRT treatment planning using the GATE Monte Carlo simulation platform for absolute and relative dose calculations

    SciTech Connect

    Benhalouche, S.; Le Maitre, A.; Visvikis, D.; Pradier, O.; Boussion, N.

    2013-02-15

    Purpose: The objective of this study was to evaluate and validate the use of the Geant4 application for emission tomography (GATE) Monte Carlo simulation platform for clinical intensity modulated radiotherapy (IMRT) dosimetry studies. Methods: The first step consisted of modeling a 6 MV photon beam linear accelerator (LINAC), with its corresponding validation carried out using percent depth dose evaluation, transverse profiles, tissue phantom ratio, and output factor on water phantom. The IMRT evaluation was performed by comparing simulation and measurements in terms of absolute and relative doses using IMRT dedicated quality assurance phantoms considering seven different patient datasets. Results: Concerning the LINAC simulated model validation tissue phantom ratios at 20 and 10 cm in water TPR{sub 10}{sup 20} obtained from GATE and measurements were 0.672 {+-} 0.063 and 0.675, respectively. In terms of percent depth dose and transverse profiles, error ranges were, respectively: 1.472%{+-} 0.285% and 4.827%{+-} 1.323% for field size of 4 Multiplication-Sign 4, 5 Multiplication-Sign 5, 10 Multiplication-Sign 10, 15 Multiplication-Sign 15, 20 Multiplication-Sign 20, 25 Multiplication-Sign 25, 30 Multiplication-Sign 30, and 40 Multiplication-Sign 40 cm{sup 2}. Most errors were observed at the edge of radiation fields because of higher dose gradient in these areas. Output factors showed good agreement between simulation and measurements with a maximum error of 1.22%. Finally, for IMRT simulations considering seven patient datasets, GATE provided good results with a relative error of 0.43%{+-} 0.25% on absolute dose between simulated and measured beams (measurements at the isocenter, volume 0.125 cm{sup 3}). Planar dose comparisons were also performed using gamma-index analysis. For the whole set of beams considered the mean gamma-index value was 0.497 {+-} 0.152 and 90.8%{+-} 3.6% of the evaluated dose points satisfied the 5%/ 4 mm criterion. Conclusions: These

  6. Lead-Induced Impairments in the Neural Processes Related to Working Memory Function

    PubMed Central

    Jin, Seong-Uk; Park, Jang Woo; Kim, Yang-Tae; Ryeom, Hun-Kyu; Lee, Jongmin; Suh, Kyung Jin; Kim, Suk Hwan; Park, Sin-Jae; Jeong, Kyoung Sook; Ham, Jung-O; Kim, Yangho; Chang, Yongmin

    2014-01-01

    Background It is well known that lead exposure induces neurotoxic effects, which can result in a variety of neurocognitive dysfunction. Especially, occupational lead exposures in adults are associated with decreases in cognitive performance including working memory. Despite recent advances in human neuroimaging techniques, the neural correlates of lead-exposed cognitive impairment remain unclear. Therefore, this study was aimed to compare the neural activations in relation to working memory function between the lead-exposed subjects and healthy controls. Methodology/Principal Findings Thirty-one lead-exposed subjects and 34 healthy subjects performed an n-back memory task during MRI scan. We performed fMRI using the 1-back and 2-back memory tasks differing in cognitive demand. Functional MRI data were analyzed using within- and between-group analysis. We found that the lead-exposed subjects showed poorer working memory performance during high memory loading task than the healthy subjects. In addition, between-group analyses revealed that the lead-exposed subjects showed reduced activation in the dorsolateral prefrontal cortex, ventrolateral prefrontal cortex, pre supplementary motor areas, and inferior parietal cortex. Conclusions/Significance Our findings suggest that functional abnormalities in the frontoparietal working memory network might contribute to impairments in maintenance and manipulation of working memory in the lead-exposed subjects. PMID:25141213

  7. Prefrontal cortical GABAergic dysfunction contributes to age-related working memory impairment.

    PubMed

    Bañuelos, Cristina; Beas, B Sofia; McQuail, Joseph A; Gilbert, Ryan J; Frazier, Charles J; Setlow, Barry; Bizon, Jennifer L

    2014-03-05

    Working memory functions supported by the prefrontal cortex decline in normal aging. Disruption of corticolimbic GABAergic inhibitory circuits can impair working memory in young subjects; however, relatively little is known regarding how aging impacts prefrontal cortical GABAergic signaling and whether such changes contribute to cognitive deficits. The current study used a rat model to evaluate the effects of aging on expression of prefrontal GABAergic synaptic proteins in relation to working memory decline, and to test whether pharmacological manipulations of prefrontal GABAergic signaling can improve working memory abilities in aged subjects. Results indicate that in aged medial prefrontal cortex (mPFC), expression of the vesicular GABA transporter VGAT was unchanged; however, there was a significant increase in expression of the GABA synthesizing enzyme GAD67, and a significant decrease in the primary neuronal GABA transporter GAT-1 and in both subunits of the GABA(B) receptor (GABA(B)R). Expression of VGAT, GAD67, and GAT-1 was not associated with working memory ability. In contrast, among aged rats, GABA(B)R expression was significantly and negatively associated with working memory performance, such that lower GABA(B)R expression predicted better working memory. Subsequent experiments showed that systemic administration of a GABA(B)R antagonist, CGP55845, dose-dependently enhanced working memory in aged rats. This enhancing effect of systemic CGP55845 was reproduced by direct intra-mPFC administration. Together, these data suggest that age-related dysregulation of GABAergic signaling in prefrontal cortex may play a causal role in impaired working memory and that targeting GABA(B)Rs may provide therapeutic benefit for age-related impairments in executive functions.

  8. Prefrontal Cortical GABAergic Dysfunction Contributes to Age-Related Working Memory Impairment

    PubMed Central

    Bañuelos, Cristina; Beas, B. Sofia; McQuail, Joseph A.; Gilbert, Ryan J.; Frazier, Charles J.; Setlow, Barry

    2014-01-01

    Working memory functions supported by the prefrontal cortex decline in normal aging. Disruption of corticolimbic GABAergic inhibitory circuits can impair working memory in young subjects; however, relatively little is known regarding how aging impacts prefrontal cortical GABAergic signaling and whether such changes contribute to cognitive deficits. The current study used a rat model to evaluate the effects of aging on expression of prefrontal GABAergic synaptic proteins in relation to working memory decline, and to test whether pharmacological manipulations of prefrontal GABAergic signaling can improve working memory abilities in aged subjects. Results indicate that in aged medial prefrontal cortex (mPFC), expression of the vesicular GABA transporter VGAT was unchanged; however, there was a significant increase in expression of the GABA synthesizing enzyme GAD67, and a significant decrease in the primary neuronal GABA transporter GAT-1 and in both subunits of the GABA(B) receptor (GABA(B)R). Expression of VGAT, GAD67, and GAT-1 was not associated with working memory ability. In contrast, among aged rats, GABA(B)R expression was significantly and negatively associated with working memory performance, such that lower GABA(B)R expression predicted better working memory. Subsequent experiments showed that systemic administration of a GABA(B)R antagonist, CGP55845, dose-dependently enhanced working memory in aged rats. This enhancing effect of systemic CGP55845 was reproduced by direct intra-mPFC administration. Together, these data suggest that age-related dysregulation of GABAergic signaling in prefrontal cortex may play a causal role in impaired working memory and that targeting GABA(B)Rs may provide therapeutic benefit for age-related impairments in executive functions. PMID:24599447

  9. Working memory performance inversely predicts spontaneous delta and theta-band scaling relations.

    PubMed

    Euler, Matthew J; Wiltshire, Travis J; Niermeyer, Madison A; Butner, Jonathan E

    2016-04-15

    Electrophysiological studies have strongly implicated theta-band activity in human working memory processes. Concurrently, work on spontaneous, non-task-related oscillations has revealed the presence of long-range temporal correlations (LRTCs) within sub-bands of the ongoing EEG, and has begun to demonstrate their functional significance. However, few studies have yet assessed the relation of LRTCs (also called scaling relations) to individual differences in cognitive abilities. The present study addressed the intersection of these two literatures by investigating the relation of narrow-band EEG scaling relations to individual differences in working memory ability, with a particular focus on the theta band. Fifty-four healthy adults completed standardized assessments of working memory and separate recordings of their spontaneous, non-task-related EEG. Scaling relations were quantified in each of the five classical EEG frequency bands via the estimation of the Hurst exponent obtained from detrended fluctuation analysis. A multilevel modeling framework was used to characterize the relation of working memory performance to scaling relations as a function of general scalp location in Cartesian space. Overall, results indicated an inverse relationship between both delta and theta scaling relations and working memory ability, which was most prominent at posterior sensors, and was independent of either spatial or individual variability in band-specific power. These findings add to the growing literature demonstrating the relevance of neural LRTCs for understanding brain functioning, and support a construct- and state-dependent view of their functional implications.

  10. The relation between working memory components and ADHD symptoms from a developmental perspective.

    PubMed

    Tillman, Carin; Eninger, Lilianne; Forssman, Linda; Bohlin, Gunilla

    2011-01-01

    The objective was to examine the relations between attention deficit hyperactivity disorder (ADHD) symptoms and four working memory (WM) components (short-term memory and central executive in verbal and visuospatial domains) in 284 6-16-year-old children from the general population. The results showed that verbal and visuospatial short-term memory and verbal central executive uniquely contributed to inattention symptoms. Age interacted with verbal short-term memory in predicting inattention, with the relation being stronger in older children. These findings support the notion of ADHD as a developmental disorder, with changes in associated neuropsychological deficits across time. The results further indicate ADHD-related deficits in several specific WM components.

  11. Time course and magnitude of movement-related gating of tactile detection in humans. II. Effects of stimulus intensity.

    PubMed

    Williams, S R; Chapman, C E

    2000-08-01

    This study examined the effect of systematically varying stimulus intensity on the time course and magnitude of movement-related gating of tactile detection and scaling in 17 human subjects trained to perform a rapid abduction of the right index finger (D2) in response to a visual cue. Electrical stimulation was delivered to D2 at five different intensities. At the lowest intensity, approximately 90% of stimuli were detected at rest (1 x P(90)); four multiples of this intensity were also tested (1.25, 1.5, 1.75, and 2. 0 x P(90)). At all intensities of stimulation, detection of stimuli applied to the moving digit was diminished significantly and in a time-dependent manner, with peak decreases occurring within +/-12 ms of the onset of electromyographic activity in the first dorsal interosseous (25-45 ms before movement onset). Reductions in the proportion of stimuli detected were greatest at the lowest stimulus intensity and progressively smaller at higher intensities. No shift in the timing of the decreases in performance was seen with increasing intensity. Once the weakest intensity at which most stimuli were perceived during movement had been established (2 x P(90)), magnitude estimation experiments were performed using two stimulus intensities, 2 x P(90) (5 subjects) and 3 x P(90) (3 subjects). Significant movement-related decreases in estimated stimulus magnitude were observed at both intensities, the time course of which was similar to the time course of reductions in detection performance. As stimulus intensity increased, the magnitude of the movement-related decrease in scaling diminished. A model of detection performance that accurately described the effect of stimulus intensity and timing on movement-related reductions in detection was created. This model was then combined with a previous model that described the effects of stimulus localization and timing to predict detection performance at a given stimulation site, intensity, and time during movement

  12. A 600-µW ultra-low-power associative processor for image pattern recognition employing magnetic tunnel junction-based nonvolatile memories with autonomic intelligent power-gating scheme

    NASA Astrophysics Data System (ADS)

    Ma, Yitao; Miura, Sadahiko; Honjo, Hiroaki; Ikeda, Shoji; Hanyu, Takahiro; Ohno, Hideo; Endoh, Tetsuo

    2016-04-01

    A novel associative processor using magnetic tunnel junction (MTJ)-based nonvolatile memories has been proposed and fabricated under a 90 nm CMOS/70 nm perpendicular-MTJ (p-MTJ) hybrid process for achieving the exceptionally low-power performance of image pattern recognition. A four-transistor 2-MTJ (4T-2MTJ) spin transfer torque magnetoresistive random access memory was adopted to completely eliminate the standby power. A self-directed intelligent power-gating (IPG) scheme specialized for this associative processor is employed to optimize the operation power by only autonomously activating currently accessed memory cells. The operations of a prototype chip at 20 MHz are demonstrated by measurement. The proposed processor can successfully carry out single texture pattern matching within 6.5 µs using 128-dimension bag-of-feature patterns, and the measured average operation power of the entire processor core is only 600 µW. Compared with the twin chip designed with 6T static random access memory, 91.2% power reductions are achieved. More than 88.0% power reductions are obtained compared with the latest associative memories. The further power performance analysis is discussed in detail, which verifies the special superiority of the proposed processor in power consumption for large-capacity memory-based VLSI systems.

  13. DNA methyltransferase activity is required for memory-related neural plasticity in the lateral amygdala.

    PubMed

    Maddox, Stephanie A; Watts, Casey S; Schafe, Glenn E

    2014-01-01

    We have previously shown that auditory Pavlovian fear conditioning is associated with an increase in DNA methyltransferase (DNMT) expression in the lateral amygdala (LA) and that intra-LA infusion or bath application of an inhibitor of DNMT activity impairs the consolidation of an auditory fear memory and long-term potentiation (LTP) at thalamic and cortical inputs to the LA, in vitro. In the present study, we use awake behaving neurophysiological techniques to examine the role of DNMT activity in memory-related neurophysiological changes accompanying fear memory consolidation and reconsolidation in the LA, in vivo. We show that auditory fear conditioning results in a training-related enhancement in the amplitude of short-latency auditory-evoked field potentials (AEFPs) in the LA. Intra-LA infusion of a DNMT inhibitor impairs both fear memory consolidation and, in parallel, the consolidation of training-related neural plasticity in the LA; that is, short-term memory (STM) and short-term training-related increases in AEFP amplitude in the LA are intact, while long-term memory (LTM) and long-term retention of training-related increases in AEFP amplitudes are impaired. In separate experiments, we show that intra-LA infusion of a DNMT inhibitor following retrieval of an auditory fear memory has no effect on post-retrieval STM or short-term retention of training-related changes in AEFP amplitude in the LA, but significantly impairs both post-retrieval LTM and long-term retention of AEFP amplitude changes in the LA. These findings are the first to demonstrate the necessity of DNMT activity in the consolidation and reconsolidation of memory-associated neural plasticity, in vivo.

  14. Use of Eye Movement Monitoring to Examine Item and Relational Memory in Schizophrenia

    PubMed Central

    Hannula, Deborah E.; Ranganath, Charan; Ramsay, Ian S.; Solomon, Marjorie; Yoon, Jong; Niendam, Tara A.; Carter, Cameron S.; Ragland, John D.

    2010-01-01

    Background Patients with schizophrenia may be impaired at remembering inter-item and item-context relationships (relational memory), even when memory for items is intact. Here, we applied the novel approach of using eye movements to assess integrity of item and relational memory in schizophrenia. This method does not rely on introspection and may be more readily translated to animal models than traditional behavioral methods. Methods Sixteen healthy controls and sixteen patients were administered a scene memory task while eye movements were monitored. During testing, participants indicated whether the scenes were unchanged, contained a new item (item manipulation), had a change in item location (relational manipulation), or were new. It was predicted that memory would be disproportionately impaired when relational changes were made. Results Results confirmed that tasks were equally difficult, and showed that patients were impaired identifying all scene types. These behavioral impairments were associated with more severe disorganization and negative symptoms. Eye movement results were more specific. Both groups looked disproportionately at critical regions of repeated versus novel scenes – an effect of scene repetition. However, in contrast to predictions, patients showed equivalent eye-movement-based memory impairment whether changes were relational or item-based. Conclusions This is the first experiment to demonstrate that eye movements can be used to investigate item and relational memory in schizophrenia. The eye movement procedure was well tolerated and was more specific than behavioral measures with respect to memory impairment. Results suggest that eye movements may be of use in clinical trials and translational studies employing animal models. PMID:20673874

  15. The Specificity of Autobiographical Memories in Early Adolescence: The Role of Mother-Child Communication and Attachment-Related Beliefs

    ERIC Educational Resources Information Center

    Bosmans, Guy; Dujardin, Adinda; Raes, Filip; Braet, Caroline

    2013-01-01

    Although autobiographical memory specificity is an important developmental feature fostering adaptation throughout life, little is known about factors related to interindividual differences in autobiographical memory specificity. The current study investigated associations with early adolescents' communication with mother about their experiences…

  16. [Current understanding of sleep, dreaming and related memory consolidation].

    PubMed

    Han, Victor Z; Shi, Jun-Han

    2013-12-01

    Sleep is a naturally recurring state found throughout the animal kingdom and characterized by a reversible loss of consciousness. Although in humans the daily amount of sleep decreases with aging, the total amount of time spent for sleep is estimated as up to one-third of one's lifetime. In mammals, sleep shows a clear daily rhythmicity as well as nightly phases, which are strongly controlled by the circadian clock located in the hypothalamic suprachiasmatic nuclei and are also regulated by ambient light. While it is certain that sleep is critical for survival in general, the functional significance of sleep is still under investigation. Dreaming is a common psychological phenomenon occurring during human sleep, yet its content and natural function, if any, are still a matter of debate. In recent years, accumulated evidence strongly supports the notion that new information acquired during the day time is processed and transformed into long-term memory in a complicated and sophisticated way during sleeping. Such information processing is commonly referred to as memory consolidation.

  17. Individual Differences in Memory Search and Their Relation to Intelligence

    PubMed Central

    Healey, M. Karl; Crutchley, Patrick; Kahana, Michael J.

    2014-01-01

    Attempts to understand why memory predicts intelligence have not fully leveraged state-of-the-art measures of recall dynamics. Using data from a multi–session free recall study we examine individual differences in measures of recall initiation and post–initiation transitions. We identify four sources of variation: a recency factor reflecting variation in the tendency to initiate recall from an item near the end of the list, a primacy factor reflecting a tendency to initiate from the beginning of the list, a temporal factor corresponding to transitions mediated by temporal associations, and a semantic factor corresponding to semantically–mediated transitions. Together these four factors account for 83% of the variability in overall recall accuracy, suggesting they provide a nearly complete picture of recall dynamics. We also show that these sources of variability account for over 80% of the variance shared between memory and intelligence. The temporal association factor was the most influential in predicting both recall accuracy and intelligence. We outline a theory of how controlled drift of temporal context may be critical across a range of cognitive activities. PMID:24730719

  18. Age-related Differences in Brain Activity during True and False Memory Retrieval

    PubMed Central

    Dennis, Nancy A.; Kim, Hongkeun; Cabeza, Roberto

    2010-01-01

    Compared to young adults, older adults show not only a reduction in true memories but also an increase in false memories. We investigated the neural bases of these age effects using functional magnetic resonance imaging and a false memory task that resembles the Deese–Roediger–McDermott (DRM) paradigm. Young and older participants were scanned during a word recognition task that included studied words and new words that were strongly associated with studied words (critical lures). During correct recognition of studied words (true memory), older adults showed weaker activity than young adults in the hippocampus but stronger activity than young adults in the retrosplenial cortex. The hippocampal reduction is consistent with age-related deficits in recollection, whereas the retrosplenial increase suggests compensatory recruitment of alternative recollection-related regions. During incorrect recognition of critical lures (false memory), older adults displayed stronger activity than young adults in the left lateral temporal cortex, a region involved in semantic processing and semantic gist. Taken together, the results suggest that older adults’ deficits in true memories reflect a decline in recollection processes mediated by the hippocampus, whereas their increased tendency to have false memories reflects their reliance on semantic gist mediated by the lateral temporal cortex. PMID:18303982

  19. Influence of anxiety in spatial memory impairments related to the loss of vestibular function in rat.

    PubMed

    Machado, M L; Lelong-Boulouard, V; Smith, P F; Freret, T; Philoxene, B; Denise, P; Besnard, S

    2012-08-30

    It is now well established that vestibular information plays an important role in spatial memory processes. Although vestibular lesions induce anxiety in humans, this finding remains controversial in rodents. However, it is possible that anxiety-related behavior is associated with spatial memory impairments after vestibular lesions. We aimed to evaluate anxiety-like behavior and the effect of an anxiolytic treatment during a complex spatial memory task in a rat model of compensated bilateral vestibular lesions. Adult rats were divided into four groups, with or without vestibular lesions and, treated or untreated by diazepam. The vestibular lesion was performed by transtympanic injection of arsanilate and compared to transtympanic saline injection. Diazepam or saline was administered 1h before each test or learning session. Vestibular-lesioned rats exhibited anxiety-like behavior which was decreased with diazepam. Spatial memory performance was similar in control-treated and untreated groups, suggesting no effect on memory at the dose of diazepam used. Spatial memory performances were not modified by anxiolytic drug treatment in vestibular-lesioned rats compared to vestibular-lesioned rats without drug treatment. We conclude that bilateral vestibular lesions in rats induced anxiety-like behavior which was unrelated to spatial memory impairment and was probably specifically related to the loss of vestibular information.

  20. Hippocampus and striatum: dynamics and interaction during acquisition and sleep-related motor sequence memory consolidation.

    PubMed

    Albouy, Geneviève; King, Bradley R; Maquet, Pierre; Doyon, Julien

    2013-11-01

    While several models of memory consolidation have previously associated hippocampal activity with declarative memory, there is now increasing evidence that the hippocampus also plays a crucial role in procedural memory. Here, we review recent human functional neuroimaging studies demonstrating that the hippocampus is involved in the acquisition and sleep-related consolidation of procedural memories, and motor sequence-based skills in particular. More specifically, we present evidence that hippocampal activity and its functional interactions with other brain structures, particularly competition with the striatum, contribute to initial learning of sequential motor behavior. Interestingly, these early cerebral representations in the hippocampus and striatum, which may interact through the prefrontal cortex, can even predict subsequent sleep-related memory consolidation processes. We propose that sleep can reorganize the activity within, as well as the functional interactions between, these structures, ultimately favoring overnight performance enhancement. Finally, we conclude by offering insights into the respective roles of these structures in procedural memory consolidation processes. We argue that, in the context of motor sequence memory consolidation, the hippocampal system triggers subsequent sleep-dependent performance enhancement whereas the striatal system is involved in the maintenance of the motor behavior over time.

  1. Examining Event-Related Potential (ERP) Correlates of Decision Bias in Recognition Memory Judgments

    PubMed Central

    Hill, Holger; Windmann, Sabine

    2014-01-01

    Memory judgments can be based on accurate memory information or on decision bias (the tendency to report that an event is part of episodic memory when one is in fact unsure). Event related potentials (ERP) correlates are important research tools for elucidating the dynamics underlying memory judgments but so far have been established only for investigations of accurate old/new discrimination. To identify the ERP correlates of bias, and observe how these interact with ERP correlates of memory, we conducted three experiments that manipulated decision bias within participants via instructions during recognition memory tests while their ERPs were recorded. In Experiment 1, the bias manipulation was performed between blocks of trials (automatized bias) and compared to trial-by-trial shifts of bias in accord with an external cue (flexibly controlled bias). In Experiment 2, the bias manipulation was performed at two different levels of accurate old/new discrimination as the memory strength of old (studied) items was varied. In Experiment 3, the bias manipulation was added to another, bottom-up driven manipulation of bias induced via familiarity. In the first two Experiments, and in the low familiarity condition of Experiment 3, we found evidence of an early frontocentral ERP component at 320 ms poststimulus (the FN320) that was sensitive to the manipulation of bias via instruction, with more negative amplitudes indexing more liberal bias. By contrast, later during the trial (500–700 ms poststimulus), bias effects interacted with old/new effects across all three experiments. Results suggest that the decision criterion is typically activated early during recognition memory trials, and is integrated with retrieved memory signals and task-specific processing demands later during the trial. More generally, the findings demonstrate how ERPs can help to specify the dynamics of recognition memory processes under top-down and bottom-up controlled retrieval conditions. PMID

  2. Endogenous cortisol elevations are related to memory facilitation only in individuals who are emotionally aroused.

    PubMed

    Abercrombie, Heather C; Speck, Nicole S; Monticelli, Roxanne M

    2006-02-01

    Animal research suggests that cortisol facilitates memory only during emotional arousal. Thus, we predicted that during mild emotion and stress elicitation, endogenous cortisol elevations would predict memory facilitation only in individuals who report high stress-related negative affect. Thirty-one men viewed neutral and emotional stimuli and then were subjected to a public speaking stress task. Area under the curve for overall cortisol output during the speech was computed. Negative affect (NA) using the PANAS state version [Watson, D., Clark, L.A., Tellegen, A., 1988. Development and validation of brief measures of positive and negative affect: the PANAS scales. J. Personality Social Psychol. 54, 1063-1070.] was measured at baseline and immediately after the speech stressor. Cortisol output during the speech and change in NA interactively predicted free recall performance assessed 2 days later. This interaction was due to the finding that higher cortisol output was related to memory facilitation only in subjects who reported high stress-related negative affect (i.e. only in those individuals whose NA increased compared to baseline). This relation was especially prominent for recall of unpleasant pictures. Subjects who reported low stress-related negative affect, no relation was found between cortisol output during the speech and memory performance. Thus, the relation between cortisol and memory appears to depend on an increase in negative affect related to stress.

  3. Training Working Memory in Childhood Enhances Coupling between Frontoparietal Control Network and Task-Related Regions

    PubMed Central

    Barnes, Jessica J.; Nobre, Anna Christina; Woolrich, Mark W.; Baker, Kate

    2016-01-01

    Working memory is a capacity upon which many everyday tasks depend and which constrains a child's educational progress. We show that a child's working memory can be significantly enhanced by intensive computer-based training, relative to a placebo control intervention, in terms of both standardized assessments of working memory and performance on a working memory task performed in a magnetoencephalography scanner. Neurophysiologically, we identified significantly increased cross-frequency phase amplitude coupling in children who completed training. Following training, the coupling between the upper alpha rhythm (at 16 Hz), recorded in superior frontal and parietal cortex, became significantly coupled with high gamma activity (at ∼90 Hz) in inferior temporal cortex. This altered neural network activity associated with cognitive skill enhancement is consistent with a framework in which slower cortical rhythms enable the dynamic regulation of higher-frequency oscillatory activity related to task-related cognitive processes. SIGNIFICANCE STATEMENT Whether we can enhance cognitive abilities through intensive training is one of the most controversial topics of cognitive psychology in recent years. This is particularly controversial in childhood, where aspects of cognition, such as working memory, are closely related to school success and are implicated in numerous developmental disorders. We provide the first neurophysiological account of how working memory training may enhance ability in childhood, using a brain recording technique called magnetoencephalography. We borrowed an analysis approach previously used with intracranial recordings in adults, or more typically in other animal models, called “phase amplitude coupling.” PMID:27559180

  4. Mechanisms of Age-Related Decline in Memory Search Across the Adult Life Span

    PubMed Central

    Hills, Thomas T.; Mata, Rui; Wilke, Andreas; Samanez-Larkin, Gregory R.

    2013-01-01

    Three alternative mechanisms for age-related decline in memory search have been proposed, which result from either reduced processing speed (global slowing hypothesis), overpersistence on categories (cluster-switching hypothesis), or the inability to maintain focus on local cues related to a decline in working memory (cue-maintenance hypothesis). We investigated these 3 hypotheses by formally modeling the semantic recall patterns of 185 adults between 27 to 99 years of age in the animal fluency task (Thurstone, 1938). The results indicate that people switch between global frequency-based retrieval cues and local item-based retrieval cues to navigate their semantic memory. Contrary to the global slowing hypothesis that predicts no qualitative differences in dynamic search processes and the cluster-switching hypothesis that predicts reduced switching between retrieval cues, the results indicate that as people age, they tend to switch more often between local and global cues per item recalled, supporting the cue-maintenance hypothesis. Additional support for the cue-maintenance hypothesis is provided by a negative correlation between switching and digit span scores and between switching and total items recalled, which suggests that cognitive control may be involved in cue maintenance and the effective search of memory. Overall, the results are consistent with age-related decline in memory search being a consequence of reduced cognitive control, consistent with models suggesting that working memory is related to goal perseveration and the ability to inhibit distracting information. PMID:23586941

  5. Problematic alcohol use among individuals with HIV: relations with everyday memory functioning and HIV symptom severity.

    PubMed

    Heinz, Adrienne J; Fogler, Kethera A; Newcomb, Michael E; Trafton, Jodie A; Bonn-Miller, Marcel O

    2014-07-01

    Problematic alcohol use has been shown to negatively impact cognitive functions germane to achieving optimal HIV health outcomes. The present study, a secondary data analysis, examined the impact of problematic alcohol use on aspects of everyday memory functioning in a sample of 172 HIV-infected individuals (22 % female; Mage = 48.37 years, SD = 8.64; 39 % Black/non-Hispanic). Additionally, we tested whether self-reported memory functioning explained the relation between problematic alcohol use and HIV symptom severity. Results indicated that problematic patterns of alcohol use were associated with lower total memory functioning, retrieval (e.g., recall-difficulty) and memory for activity (e.g., what you did yesterday) and greater HIV symptom severity. Memory functioning mediated the relation between problematic alcohol use and HIV symptom severity. However, the direction of this relation was unclear as HIV symptom severity also mediated the relation between problematic alcohol use and memory functioning. Findings highlight the importance of integrated care for HIV and alcohol use disorders and suggest that routine alcohol and cognitive screenings may bolster health outcomes among this vulnerable population.

  6. Chronic Corticosterone Exposure Persistently Elevates the Expression of Memory-Related Genes in the Lateral Amygdala and Enhances the Consolidation of a Pavlovian Fear Memory

    PubMed Central

    Monsey, Melissa S.; Boyle, Lara M.; Zhang, Melinda L.; Nguyen, Caroline P.; Kronman, Hope G.; Ota, Kristie T.; Duman, Ronald S.; Taylor, Jane R.; Schafe, Glenn E.

    2014-01-01

    Chronic exposure to stress has been widely implicated in the development of anxiety disorders, yet relatively little is known about the long-term effects of chronic stress on amygdala-dependent memory formation. Here, we examined the effects of a history of chronic exposure to the stress-associated adrenal steroid corticosterone (CORT) on the consolidation of a fear memory and the expression of memory-related immediate early genes (IEGs) in the lateral nucleus of the amygdala (LA). Rats received chronic exposure to CORT (50 μg/ml) in their drinking water for 2 weeks and were then titrated off the CORT for an additional 6 days followed by a 2 week ‘wash-out’ period consisting of access to plain water. Rats were then either sacrificed to examine the expression of memory-related IEG expression in the LA or given auditory Pavlovian fear conditioning. We show that chronic exposure to CORT leads to a persistent elevation in the expression of the IEGs Arc/Arg3.1 and Egr-1 in the LA. Further, we show that rats with a history of chronic CORT exposure exhibit enhanced consolidation of a fear memory; short-term memory (STM) is not affected, while long-term memory (LTM) is significantly enhanced. Treatment with the selective serotonin reuptake inhibitor (SSRI) fluoxetine following the chronic CORT exposure period was observed to effectively reverse both the persistent CORT-related increases in memory-related IEG expression in the LA and the CORT-related enhancement in fear memory consolidation. Our findings suggest that chronic exposure to CORT can regulate memory-related IEG expression and fear memory consolidation processes in the LA in a long-lasting manner and that treatment with fluoxetine can reverse these effects. PMID:24618807

  7. The roles of gender and temporal distance in the recall of dissonant self-related memories.

    PubMed

    Grysman, Azriel

    2014-10-01

    This study examined strategies employed to support a positive self-image in the face of dissonant self-related memories, especially focusing on the role of gender. Participants (N=498) were recruited online and identified a self-descriptive trait. They then reported a memory of a time when they did or did not act according to that trait. Participants distanced themselves from dissonant, self-related memories by downplaying the event's importance and relevance to identity and by emphasizing their lack of agency and the degree to which they had changed. Additionally, participants reported dissonant events from further in the past than consonant events, a tendency displayed more strongly amongst women than men. Women also rated events as more pertinent to the self on questionnaire measures. Findings demonstrate ways that autobiographical memories are reported and organized to support a positive self-image, and deepen an understanding of the role of gender in this process.

  8. Relational and conjunctive binding functions dissociate in short-term memory.

    PubMed

    Parra, Mario A; Fabi, Katia; Luzzi, Simona; Cubelli, Roberto; Hernandez Valdez, Maria; Della Sala, Sergio

    2015-02-01

    Remembering complex events requires binding features within unified objects (conjunctions) and holding associations between objects (relations). Recent studies suggest that the two functions dissociate in long-term memory (LTM). Less is known about their functional organization in short-term memory (STM). The present study investigated this issue in patient AE affected by a stroke which caused damage to brain regions known to be relevant for relational functions both in LTM and in STM (i.e., the hippocampus). The assessment involved a battery of standard neuropsychological tasks and STM binding tasks. One STM binding task (Experiment 1) presented common objects and common colors forming either pairs (relations) or integrated objects (conjunctions). Free recall of relations or conjunctions was assessed. A second STM binding task used random polygons and non-primary colors instead (Experiment 2). Memory was assessed by selecting the features that made up the relations or the conjunctions from a set of single polygons and a set of single colors. The neuropsychological assessment revealed impaired delayed memory in AE. AE's pronounced relational STM binding deficits contrasted with his completely preserved conjunctive binding functions in both Experiments 1 and 2. Only 2.35% and 1.14% of the population were expected to have a discrepancy more extreme than that presented by AE in Experiments 1 and 2, respectively. Processing relations and conjunctions of very elementary nonspatial features in STM led to dissociating performances in AE. These findings may inform current theories of memory decline such as those linked to cognitive aging.

  9. Neurocognitive Systems Related to Real-World Prospective Memory

    PubMed Central

    Kalpouzos, Grégoria; Eriksson, Johan; Sjölie, Daniel; Molin, Jonas; Nyberg, Lars

    2010-01-01

    Background Prospective memory (PM) denotes the ability to remember to perform actions in the future. It has been argued that standard laboratory paradigms fail to capture core aspects of PM. Methodology/Principal Findings We combined functional MRI, virtual reality, eye-tracking and verbal reports to explore the dynamic allocation of neurocognitive processes during a naturalistic PM task where individuals performed errands in a realistic model of their residential town. Based on eye movement data and verbal reports, we modeled PM as an iterative loop of five sustained and transient phases: intention maintenance before target detection (TD), TD, intention maintenance after TD, action, and switching, the latter representing the activation of a new intention in mind. The fMRI analyses revealed continuous engagement of a top-down fronto-parietal network throughout the entire task, likely subserving goal maintenance in mind. In addition, a shift was observed from a perceptual (occipital) system while searching for places to go, to a mnemonic (temporo-parietal, fronto-hippocampal) system for remembering what actions to perform after TD. Updating of the top-down fronto-parietal network occurred at both TD and switching, the latter likely also being characterized by frontopolar activity. Conclusion/Significance Taken together, these findings show how brain systems complementary interact during real-world PM, and support a more complete model of PM that can be applied to naturalistic PM tasks and that we named PROspective MEmory DYnamic (PROMEDY) model because of its dynamics on both multi-phase iteration and the interactions of distinct neurocognitive networks. PMID:20949046

  10. Memory bias for schema-related stimuli in individuals with bulimia nervosa.

    PubMed

    Legenbauer, Tanja; Maul, Bärbel; Rühl, Ilka; Kleinstäuber, Maria; Hiller, Wolfgang

    2010-03-01

    This study investigates whether individuals with bulimia nervosa (BN) have a memory bias in relation to explicit memory (cued and free recall vs. verbal and pictorial recognition tasks). Twenty-five participants diagnosed with BN and 27 normal controls (NC) were exposed to body-related, food-related, and neutral TV commercials, and then recall and recognition rates were assessed. Poorer recognition and recall of body-related stimuli was found for BN in comparison to NC, suggesting a memory bias. Results are discussed in relation to previous studies, along with suggestions as to how future studies can gain more insight into dysfunctions in information processing that can lead to the maintenance of eating disorders.

  11. Brooding Is Related to Neural Alterations during Autobiographical Memory Retrieval in Aging

    PubMed Central

    Schneider, Sophia; Brassen, Stefanie

    2016-01-01

    Brooding rumination is considered a central aspect of depression in midlife. As older people tend to review their past, rumination tendency might be particularly crucial in late life since it might hinder older adults to adequately evaluate previous events. We scanned 22 non-depressed older adults with varying degrees of brooding tendency with functional magnetic resonance imaging (MRI) while they performed the construction and elaboration of autobiographical memories. Behavioral findings demonstrate that brooders reported lower mood states, needed more time for memory construction and rated their memories as less detailed and less positive. On the neural level, brooding tendency was related to increased amygdala activation during the search for specific memories and reduced engagement of cortical networks during elaboration. Moreover, coupling patterns of the subgenual cingulate cortex with the hippocampus (HC) and the amygdala predicted details and less positive valence of memories in brooders. Our findings support the hypothesis that ruminative thinking interferes with the search for specific memories while facilitating the uncontrolled retrieval of negatively biased self-schemes. The observed neurobehavioral dysfunctions might put older people with brooding tendency at high risk for becoming depressed when reviewing their past. Training of autobiographical memory ability might therefore be a promising approach to increase resilience against depression in late-life. PMID:27695414

  12. Olfactory short-term memory encoding and maintenance - an event-related potential study.

    PubMed

    Lenk, Steffen; Bluschke, Annet; Beste, Christian; Iannilli, Emilia; Rößner, Veit; Hummel, Thomas; Bender, Stephan

    2014-09-01

    This study examined whether the memory encoding and short term maintenance of olfactory stimuli is associated with neurophysiological activation patterns which parallel those described for sensory modalities such as vision and auditory. We examined olfactory event-related potentials in an olfactory change detection task in twenty-four healthy adults and compared the measured activation to that found during passive olfactory stimulation. During the early olfactory post-processing phase, we found a sustained negativity over bilateral frontotemporal areas in the passive perception condition which was enhanced in the active memory task. There was no significant lateralization in either experimental condition. During the maintenance interval at the end of the delay period, we still found sustained activation over bilateral frontotemporal areas which was more negative in trials with correct - as compared to incorrect - behavioural responses. This was complemented by a general significantly stronger frontocentral activation. Summarizing, we were able to show that olfactory short term memory involves a parallel sequence of activation as found in other sensory modalities. In addition to olfactory-specific frontotemporal activations in the memory encoding phase, we found slow cortical potentials over frontocentral areas during the memory maintenance phase indicating the activation of a supramodal memory maintenance system. These findings could represent the neurophysiological underpinning of the 'olfactory flacon', the olfactory counter-part to the visual sketchpad and phonological loop embedded in Baddeley's working memory model.

  13. Cyclic nucleotide gated channels and related signaling components in plant innate immunity.

    PubMed

    Ma, Wei; Smigel, Andries; Verma, Rajeev; Berkowitz, Gerald A

    2009-04-01

    Although plants lack the mobile sentry cells present in animal innate immune systems, plants have developed complex innate immune reactions triggering basal resistance and the hypersensitive response (HR). Cytosolic Ca(2+) elevation is considered to be an important early event in this pathogen response signal transduction cascade. Plasma membrane (PM)-localized cyclic nucleotide gated channels (CNGCs) contribute to the cytosolic Ca(2+) rise upon pathogen perception. Recent work suggests that some PM-localized leucine-rich-repeat receptor-like kinases (LRR-RLKs) may be involved in the perception of pathogen associated molecular pattern molecules and triggering some pathogen responses in plants, some of these LRR-RLKs might have cyclic nucleotide cyclase activity. The recognition of pathogens may be connected to cyclic nucleotide generation and the activation of CNGCs, followed by cytosolic Ca(2+) increase and downstream signaling events (possibly involving nitric oxide, reactive oxygen species (ROS), calmodulin (CaM), CaM-like protein (CML) and protein kinases). Notably, CaM or CML could be the crucial sensor downstream from the early Ca(2+) signal leading to nitric oxide (NO) production during plant innate immune responses.

  14. Genistein improves sensorimotor gating: Mechanisms related to its neuroprotective effects on the striatum.

    PubMed

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

    2016-06-01

    Huntington's disease (HD) is a neurodegenerative disorder, characterized by selective atrophy in the striatum, particularly the medium spiny GABAergic efferent neurons. This results in striatal sensorimotor gating deficits. Systemic administration of 3-nitropropionic acid (3-NPA) produces selective lesions mimicking those of HD. Males were found to be more susceptible to 3-NPA-induced neurotoxicity than females, suggesting neuroprotective effects of estrogens. Phytoestrogens, including genistein, are good estrogenic alternatives that keep their beneficial effects on non-reproductive organs and lack the potential hazardous side effects. The current study was designed to investigate the potential beneficial effects of genistein in 3-NPA-induced HD in ovariectomized rats. Results showed that 3-NPA (20 mg/kg) administration caused significant disruption of the rats' locomotor activity and prepulse inhibition. In addition, it decreased striatal ATP levels and increased oxidative stress, inflammatory and apoptotic markers with striatal focal hemorrhage and gliosis. Pretreatment with 17β-estradiol (2.5 mg/kg) or genistein (20 mg/kg) led to a significant improvement of behavioral parameters, increased ATP production, decreased oxidative stress, attenuated inflammation and apoptosis. Therefore, this study suggests potential neuroprotective effects of genistein in ovariectomized rats challenged with 3-NPA.

  15. Memory deficits associated with sublethal cyanide poisoning relative to cyanate toxicity in rodents.

    PubMed

    Kimani, S; Sinei, K; Bukachi, F; Tshala-Katumbay, D; Maitai, C

    2014-03-01

    Food (cassava) linamarin is metabolized into neurotoxicants cyanide and cyanate, metabolites of which we sought to elucidate the differential toxicity effects on memory. Young 6-8 weeks old male rats were treated intraperitoneally with either 2.5 mg/kg body weight (bw) cyanide (NaCN), or 50 mg/kg bw cyanate (NaOCN), or 1 μl/g bw saline, daily for 6 weeks. Short-term and long-term memories were assessed using a radial arm maze (RAM) testing paradigm. Toxic exposures had an influence on short-term working memory with fewer correct arm entries (F(2, 19) = 4.57 p < 0.05), higher working memory errors (WME) (F(2, 19) = 5.09, p < 0.05) and longer RAM navigation time (F(2, 19) = 3.91, p < 0.05) for NaOCN relative to NaCN and saline treatments. The long-term working memory was significantly impaired by cyanide with fewer correct arm entries (F(2, 19) = 7.45, p < 0.01) and increased working memory errors (F(2, 19) = 9.35 p < 0.05) in NaCN relative to NaOCN or vehicle treated animals. Reference memory was not affected by either cyanide or cyanate. Our study findings provide an experimental evidence for the biological plausibility that cassava cyanogens may induce cognition deficits. Differential patterns of memory deficits may reflect the differences in toxicity mechanisms of NaOCN relative to NaCN. Cognition deficits associated with cassava cyanogenesis may reflect a dual toxicity effect of cyanide and cyanate.

  16. Disruption of Relational Processing Underlies Poor Memory for Order

    ERIC Educational Resources Information Center

    Jonker, Tanya R.; MacLeod, Colin M.

    2015-01-01

    McDaniel and Bugg (2008) proposed that relatively uncommon stimuli and encoding tasks encourage elaborative encoding of individual items (item-specific processing), whereas relatively typical or common encoding tasks encourage encoding of associations among list items (relational processing). It is this relational processing that is thought to…

  17. The development of control processes supporting source memory discrimination as revealed by event-related potentials.

    PubMed

    de Chastelaine, Marianne; Friedman, David; Cycowicz, Yael M

    2007-08-01

    Improvement in source memory performance throughout childhood is thought to be mediated by the development of executive control. As postretrieval control processes may be better time-locked to the recognition response rather than the retrieval cue, the development of processes underlying source memory was investigated with both stimulus- and response-locked event-related potentials (ERPs). These were recorded in children, adolescents, and adults during a recognition memory exclusion task. Green- and red-outlined pictures were studied, but were tested in black outline. The test requirement was to endorse old items shown in one study color ("targets") and to reject new items along with old items shown in the alternative study color ("nontargets"). Source memory improved with age. All age groups retrieved target and nontarget memories as reflected by reliable parietal episodic memory (EM) effects, a stimulus-locked ERP correlate of recollection. Response-locked ERPs to targets and nontargets diverged in all groups prior to the response, although this occurred at an increasingly earlier time point with age. We suggest these findings reflect the implementation of attentional control mechanisms to enhance target memories and facilitate response selection with the greatest and least success, respectively, in adults and children. In adults only, response-locked ERPs revealed an early-onsetting parietal negativity for nontargets, but not for targets. This was suggested to reflect adults' ability to consistently inhibit prepotent target responses for nontargets. The findings support the notion that the development of source memory relies on the maturation of control processes that serve to enhance accurate selection of task-relevant memories.

  18. Need for cognition is related to the rejection (but not the acceptance) of false memories.

    PubMed

    Leding, Juliana K

    2013-01-01

    Need for cognition (NFC) and rates of false recognition were studied in the context of the memory conjunction paradigm. Past research has shown that NFC is related to false recognition and false recall (Graham, 2007; Leding, 2011) in the Deese-Roediger-McDermott (DRM) paradigm, with high-NFC people experiencing more false memories. The present study extended this research to determine whether the findings of high-NFC people experiencing higher levels of false memories could be extended to other false memory paradigms. The present study also examined rates of high-confidence rejections of lures and recollection rejection responses. It was found that there were no significant differences for high- and low-NFC people in false recognition but that high-NFC people were more likely to use high-confidence rejections and have recollection rejection responses when they did reject lures.

  19. Psychosocial stress enhances non-drug-related positive memory retrieval in male abstinent heroin addicts.

    PubMed

    Zhao, Li-Yan; Shi, Jie; Zhang, Xiao-Li; Lu, Lin

    2010-11-12

    Stress exposure in addicted individuals is known to provoke drug craving, presumably through a memory-like process, but less is known about the effects of stress on non-drug-related affective memory retrieval per se in such individuals, which is likely to provide important insights into therapy for relapse. In present study, we explored the effect of stress on retrieval of neutral and emotionally valenced (positive and negative) words in abstinent heroin addicts. In present study, 28 male inpatient abstinent heroin addicts and 20 sex-, age-, education- and economic status-matched healthy control participants were assessed for 24h delayed recall of valenced and neutral word lists on two occasions 4 weeks apart-once in a nonstress control condition, once after exposure to the Trier Social Stress Test in a counterbalanced design. In addition, attention, working memory, blood pressure, heart rate and salivary cortisol were assessed. We found acute stress at the time of word list recall enhanced retrieval of positively valenced words, but no effect on negative and neutral word retrieval in abstinent heroin addicts was observed. No changes were detected for attention and working memory. The stressor induced a significant increase in salivary free cortisol, blood pressure and heart rate. Stress can enhance non-drug-related positive memory in abstinent heroin addicts. Our findings will provide richer information in understanding dysregulation of their emotional memory processing under stress and hopefully provide insight into designing improved treatments for drug addiction.

  20. The Organizational Role of Testicular Hormones and the Androgen Receptor in Anxiety-Related Behaviors and Sensorimotor Gating in Rats

    PubMed Central

    Jordan, Cynthia L.; Breedlove, S. Marc

    2011-01-01

    Perinatal exposure to testosterone (T), which can act upon both the androgen receptor (AR) and, via aromatization of T into estrogens, upon estrogen receptors, organizes many adult behaviors in rodents. We compared behaviors in wild-type (WT) male rats and AR-deficient rats with the testicular feminization mutation (Tfm), which on the day of birth were either gonadectomized (Neo-Gdx) or sham operated. In adulthood, all rats were either gonadectomized or sham operated and implanted with T capsules to equilibrate circulating androgens. In each of four tests of behavior related to anxiety (open field, novel object exposure, light/dark box, and elevated plus maze), Neo-Gdx rats showed decreased indices of anxiety and increased activity compared with rats sham operated on the day of birth, with no differences between WT or Tfm males within treatment groups. These results indicate that testicular hormones act in development to increase adult indices of anxiety and decrease activity in males and that functional ARs are not required for this effect. Acoustic startle response was also reduced by Neo-Gdx, suggesting that postnatal testicular secretions potentiate this behavior as well. Adult corticosterone levels and sensorimotor gating, as measured by prepulse inhibition of the acoustic startle response, were increased by neonatal castration in both WT and Tfm rats. These findings indicate a role of T before adulthood in the organization of anxiety-related behaviors, activity, the hypothalamic-pituitary-adrenal axis, and sensorimotor gating in rats, all of which appears to be AR independent. PMID:21325044

  1. Age-related spatial working memory deficits in homing pigeons (Columba livia).

    PubMed

    Coppola, Vincent J; Hough, Gerald; Bingman, Verner P

    2014-12-01

    The hippocampus is particularly susceptible to age-related degeneration that, like hippocampal lesions, is thought to lead to age-related decline in spatial memory and navigation. Lesions to the avian hippocampal formation (HF) also result in impaired spatial memory and navigation, but the relationship between aging and HF-dependent spatial cognition is unknown. To investigate possible age-related decline in avian spatial cognition, the current study investigated spatial working memory performance in older homing pigeons (10+ years of age). Pigeons completed a behavioral procedure nearly identical to the delayed spatial, win-shift procedure in a modified radial arm maze that has been previously used to study spatial working memory in rats and pigeons. The results revealed that the older pigeons required a greater number of choices to task completion and were less accurate with their first 4 choices as compared to younger pigeons (1-2 years of age). In addition, older pigeons were more likely to adopt a stereotyped sampling strategy, which explained in part their impaired performance. To the best of our knowledge, this study is the first to demonstrate an age-related impairment of HF-dependent, spatial memory in birds. Implications and future directions of the findings are discussed.

  2. Motor Skills Enhance Procedural Memory Formation and Protect against Age-Related Decline

    PubMed Central

    Müller, Nils C. J.; Genzel, Lisa; Konrad, Boris N.; Pawlowski, Marcel; Neville, David; Fernández, Guillén; Steiger, Axel

    2016-01-01

    The ability to consolidate procedural memories declines with increasing age. Prior knowledge enhances learning and memory consolidation of novel but related information in various domains. Here, we present evidence that prior motor experience–in our case piano skills–increases procedural learning and has a protective effect against age-related decline for the consolidation of novel but related manual movements. In our main experiment, we tested 128 participants with a sequential finger-tapping motor task during two sessions 24 hours apart. We observed enhanced online learning speed and offline memory consolidation for piano players. Enhanced memory consolidation was driven by a strong effect in older participants, whereas younger participants did not benefit significantly from prior piano experience. In a follow up independent control experiment, this compensatory effect of piano experience was not visible after a brief offline period of 30 minutes, hence requiring an extended consolidation window potentially involving sleep. Through a further control experiment, we rejected the possibility that the decreased effect in younger participants was caused by training saturation. We discuss our results in the context of the neurobiological schema approach and suggest that prior experience has the potential to rescue memory consolidation from age-related cognitive decline. PMID:27333186

  3. Working Memory Is Related to Perceptual Processing: A Case from Color Perception

    ERIC Educational Resources Information Center

    Allen, Elizabeth C.; Beilock, Sian L.; Shevell, Steven K.

    2011-01-01

    We explored the relation between individual differences in working memory (WM) and color constancy, the phenomenon of color perception that allows us to perceive the color of an object as relatively stable under changes in illumination. Successive color constancy (measured by first viewing a colored surface under a particular illumination and…

  4. Morphological Information and Memory Resources in Children's Processing of Relative Clauses in German

    ERIC Educational Resources Information Center

    Arosio, Fabrizio; Yatsushiro, Kazuko; Forgiarini, Matteo; Guasti, Maria Teresa

    2012-01-01

    We investigated the processing of agreement marking and case marking in the comprehension of German relative clauses in 48 seven-year-old monolingual German-speaking children in a picture selection task. We examined the relation between the effectiveness of these different morphological cues and individual memory resources as measured by a…

  5. Differences in Processing of Taxonomic and Sequential Relations in Semantic Memory: An fMRI Investigation

    ERIC Educational Resources Information Center

    Kuchinke, Lars; van der Meer, Elke; Krueger, Frank

    2009-01-01

    Conceptual knowledge of our world is represented in semantic memory in terms of concepts and semantic relations between concepts. We used functional magnetic resonance imaging (fMRI) to examine the cortical regions underlying the processing of sequential and taxonomic relations. Participants were presented verbal cues and performed three tasks:…

  6. Thinking about the Future Early in Life: The Role of Relational Memory

    ERIC Educational Resources Information Center

    Richmond, Jenny L.; Pan, Rose

    2013-01-01

    The constructive episodic simulation hypothesis suggests that we imagine possible future events by flexibly recombining details of past experiences to produce novel scenarios. Here we tested this hypothesis by determining whether episodic future thinking is related to relational memory ability during the preschool years. Children (3- to…

  7. Verbal Memory Deficits in Relation to Organization Strategy in High- and Low-Functioning Autistic Children

    ERIC Educational Resources Information Center

    Cheung, Mei-chun; Chan, Agnes S.; Sze, Sophia L.; Leung, Winnie W.; To, Cho Yee

    2010-01-01

    The present study examined the verbal memory profile and its relation to organizational strategies in high-functioning (Hi-AUT) and low-functioning (Lo-AUT) children with autism. Twenty-two Hi-AUT and 16 Lo-AUT, and 22 age-, gender- and handedness-matched normal children (NC) were required to remember a list of semantically related words for…

  8. IFN-γ differentially modulates memory-related processes under basal and chronic stressor conditions

    PubMed Central

    Litteljohn, Darcy; Nelson, Eric; Hayley, Shawn

    2014-01-01

    Cytokines are inflammatory messengers that orchestrate the brain’s response to immunological challenges, as well as possibly even toxic and psychological insults. We previously reported that genetic ablation of the pro-inflammatory cytokine, interferon-gamma (IFN-γ), attenuated some of the corticosteroid, cytokine, and limbic dopaminergic variations induced by 6 weeks of exposure to an unpredictable psychologically relevant stressor. Presently, we sought to determine whether a lack of IFN-γ would likewise modify the impact of chronic stress on hippocampus-dependent memory function and related neurotransmitter and neurotrophin signaling systems. As predicted, chronic stress impaired spatial recognition memory (Y-maze task) in the wild-type animals. In contrast, though the IFN-γ knockouts (KOs) showed memory disturbances in the basal state, under conditions of chronic stress these mice actually exhibited facilitated memory performance. Paralleling these findings, while overall the KOs displayed altered noradrenergic and/or serotonergic activity in the hippocampus and locus coeruleus, norepinephrine utilization in both of these memory-related brain regions was selectively increased among the chronically stressed KOs. However, contrary to our expectations, neither IFN-γ deletion nor chronic stressor exposure significantly affected nucleus accumbens dopaminergic neurotransmission or hippocampal brain-derived neurotrophic factor protein expression. These findings add to a growing body of evidence implicating cytokines in the often differential regulation of neurobehavioral processes in health and disease. Whereas in the basal state IFN-γ appears to be involved in sustaining memory function and the activity of related brain monoamine systems, in the face of ongoing psychologically relevant stress the cytokine may, in fact, act to restrict potentially adaptive central noradrenergic and spatial memory responses. PMID:25477784

  9. Context Memory Decline in Middle Aged Adults is Related to Changes in Prefrontal Cortex Function.

    PubMed

    Kwon, Diana; Maillet, David; Pasvanis, Stamatoula; Ankudowich, Elizabeth; Grady, Cheryl L; Rajah, M Natasha

    2016-06-01

    The ability to encode and retrieve spatial and temporal contextual details of episodic memories (context memory) begins to decline at midlife. In the current study, event-related fMRI was used to investigate the neural correlates of context memory decline in healthy middle aged adults (MA) compared with young adults (YA). Participants were scanned while performing easy and hard versions of spatial and temporal context memory tasks. Scans were obtained at encoding and retrieval. Significant reductions in context memory retrieval accuracy were observed in MA, compared with YA. The fMRI results revealed that overall, both groups exhibited similar patterns of brain activity in parahippocampal cortex, ventral occipito-temporal regions and prefrontal cortex (PFC) during encoding. In contrast, at retrieval, there were group differences in ventral occipito-temporal and PFC activity, due to these regions being more activated in MA, compared with YA. Furthermore, only in YA, increased encoding activity in ventrolateral PFC, and increased retrieval activity in occipital cortex, predicted increased retrieval accuracy. In MA, increased retrieval activity in anterior PFC predicted increased retrieval accuracy. These results suggest that there are changes in PFC contributions to context memory at midlife.

  10. Developmental dyscalculia is related to visuo-spatial memory and inhibition impairment.

    PubMed

    Szucs, Denes; Devine, Amy; Soltesz, Fruzsina; Nobes, Alison; Gabriel, Florence

    2013-01-01

    Developmental dyscalculia is thought to be a specific impairment of mathematics ability. Currently dominant cognitive neuroscience theories of developmental dyscalculia suggest that it originates from the impairment of the magnitude representation of the human brain, residing in the intraparietal sulcus, or from impaired connections between number symbols and the magnitude representation. However, behavioral research offers several alternative theories for developmental dyscalculia and neuro-imaging also suggests that impairments in developmental dyscalculia may be linked to disruptions of other functions of the intraparietal sulcus than the magnitude representation. Strikingly, the magnitude representation theory has never been explicitly contrasted with a range of alternatives in a systematic fashion. Here we have filled this gap by directly contrasting five alternative theories (magnitude representation, working memory, inhibition, attention and spatial processing) of developmental dyscalculia in 9-10-year-old primary school children. Participants were selected from a pool of 1004 children and took part in 16 tests and nine experiments. The dominant features of developmental dyscalculia are visuo-spatial working memory, visuo-spatial short-term memory and inhibitory function (interference suppression) impairment. We hypothesize that inhibition impairment is related to the disruption of central executive memory function. Potential problems of visuo-spatial processing and attentional function in developmental dyscalculia probably depend on short-term memory/working memory and inhibition impairments. The magnitude representation theory of developmental dyscalculia was not supported.

  11. Double dissociation between rules and memory in music: an event-related potential study.

    PubMed

    Miranda, Robbin A; Ullman, Michael T

    2007-11-01

    Language and music share a number of characteristics. Crucially, both domains depend on both rules and memorized representations. Double dissociations between the neurocognition of rule-governed and memory-based knowledge have been found in language but not music. Here, the neural bases of both of these aspects of music were examined with an event-related potential (ERP) study of note violations in melodies. Rule-only violations consisted of out-of-key deviant notes that violated tonal harmony rules in novel (unfamiliar) melodies. Memory-only violations consisted of in-key deviant notes in familiar well-known melodies; these notes followed musical rules but deviated from the actual melodies. Finally, out-of-key notes in familiar well-known melodies constituted violations of both rules and memory. All three conditions were presented, within-subjects, to healthy young adults, half musicians and half non-musicians. The results revealed a double dissociation, independent of musical training, between rules and memory: both rule violation conditions, but not the memory-only violations, elicited an early, somewhat right-lateralized anterior-central negativity (ERAN), consistent with previous studies of rule violations in music, and analogous to the early left-lateralized anterior negativities elicited by rule violations in language. In contrast, both memory violation conditions, but not the rule-only violation, elicited a posterior negativity that might be characterized as an N400, an ERP component that depends, at least in part, on the processing of representations stored in long-term memory, both in language and in other domains. The results suggest that the neurocognitive rule/memory dissociation extends from language to music, further strengthening the similarities between the two domains.

  12. 20. DETAIL VIEW OF SUBMERSIBLE GATE, SHOWING GATE ARMS, GATE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    20. DETAIL VIEW OF SUBMERSIBLE GATE, SHOWING GATE ARMS, GATE PIERS, TRUNNION PIN AND GATE GAUGE, LOOKING NORTHEAST - Upper Mississippi River 9-Foot Channel, Lock & Dam No. 8, On Mississippi River near Houston County, MN, Genoa, Vernon County, WI

  13. 21. DETAIL VIEW OF SUBMERSIBLE TAINTER GATE, SHOWING GATE, GATE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    21. DETAIL VIEW OF SUBMERSIBLE TAINTER GATE, SHOWING GATE, GATE ARM, TRUNNION PIN, PIER AND GATE GAUGE, LOOKING EAST - Upper Mississippi River 9-Foot Channel, Lock & Dam No. 10, Guttenberg, Clayton County, IA

  14. 17. DETAIL VIEW OF NONSUBMERSIBLE TAINTER GATE, SHOWING GATES, GATE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    17. DETAIL VIEW OF NON-SUBMERSIBLE TAINTER GATE, SHOWING GATES, GATE ARMS, PIERS AND DAM BRIDGE, WITH ROLLER GATE HEADHOUSE IN BACKGROUND, LOOKING SOUTHEAST - Upper Mississippi River 9-Foot Channel, Lock & Dam No. 9, Lynxville, Crawford County, WI

  15. What goes where? Eye tracking reveals spatial relational memory during infancy.

    PubMed

    Richmond, Jenny L; Zhao, Jenna L; Burns, Mary A

    2015-02-01

    Episodic memory involves binding components of an event (who, what, when, and where) into a relational representation. The ability to encode information about the relative locations of objects (i.e., spatial relational memory) is a key component of episodic memory. Here we used eye tracking to test whether infants and toddlers learn about the spatial relations among objects. In Experiment 1, 9-, 18-, and 27-month olds were familiarized with an array of three objects. Following familiarization, they saw test arrays in which two of the objects had been replaced with novel ones (object switch condition) and arrays in which two of the objects had switched positions (location switch condition). Both 18- and 27-month olds looked significantly longer than would be predicted by chance at the objects that had switched spatial locations; however, 9-month olds did not. In Experiment 2, we showed that, given sufficient familiarization time, 9-month olds were also capable of detecting disruptions to the spatial relations among an array of objects. These results have important implications for our understanding of spatial relational memory development.

  16. Bulk supertranslation memories: A concept reshaping the vacua and black holes of general relativity

    NASA Astrophysics Data System (ADS)

    Compère, Geoffrey

    2016-07-01

    The memory effect is a prediction of general relativity on the same footing as the existence of gravitational waves. The memory effect is understood at future null infinity as a transition induced by null radiation from a Poincaré vacuum to another vacuum. Those are related by a supertranslation, which is a fundamental symmetry of asymptotically flat spacetimes. In this paper, I argue that finite supertranslation diffeomorphisms should be extended into the bulk spacetime consistently with canonical charge conservation. It then leads to fascinating geometrical features of gravitational Poincaré vacua. I then argue that in the process of black hole merger or gravitational collapse, dramatic but computable memory effects occur. They lead to a final stationary metric which qualitatively deviates from the Schwarzschild metric.

  17. Testosterone levels in healthy men are related to amygdala reactivity and memory performance.

    PubMed

    Ackermann, Sandra; Spalek, Klara; Rasch, Björn; Gschwind, Leo; Coynel, David; Fastenrath, Matthias; Papassotiropoulos, Andreas; de Quervain, Dominique J-F

    2012-09-01

    Testosterone is a steroid hormone thought to influence both emotional and cognitive functions. It is unknown, however, if testosterone also affects the interaction between these two domains, such as the emotional arousal-induced enhancement of memory. Healthy subjects (N=234) encoded pictures taken from the International Affective Picture System (IAPS) during functional magnetic resonance imaging (fMRI) and underwent a free recall test 10 min after memory encoding. We show that higher endogenous testosterone levels at encoding were associated with higher arousal ratings of neutral pictures in men. fMRI analysis revealed that higher testosterone levels were related to increased brain activation in the amygdala during encoding of neutral pictures. Moreover, endogenous testosterone levels were positively correlated with the number of freely recalled neutral pictures. No such relations were found in women. These findings point to a male-specific role for testosterone in enhancing memory by increasing the biological salience of incoming information.

  18. Semantic false memories in the form of derived relational intrusions following training.

    PubMed

    Guinther, Paul M; Dougher, Michael J

    2010-05-01

    Contemporary behavior analytic research is making headway in characterizing memory phenomena that typically have been characterized by cognitive models, and the current study extends this development by producing "false memories" in the form of functional equivalence responding. A match-to-sample training procedure was administered in order to encourage participants to treat groups of unrelated English words as being interchangeable. Following training, participants were presented with a list of words from within one of the groups for a free recall test and a recognition test. Results showed that participants were more likely to falsely recall and recognize words that had been assigned to the same group as the list words during prior training, relative to words not assigned to the same group and relative to words that co-occurred with list words. These results indicate that semantic relatedness can be experimentally manipulated in order to produce specific false memories.

  19. Understanding low reliability of memories for neutral information encoded under stress: alterations in memory-related activation in the hippocampus and midbrain.

    PubMed

    Qin, Shaozheng; Hermans, Erno J; van Marle, Hein J F; Fernández, Guillén

    2012-03-21

    Exposure to an acute stressor can lead to unreliable remembrance of intrinsically neutral information, as exemplified by low reliability of eyewitness memories, which stands in contrast with enhanced memory for the stressful incident itself. Stress-sensitive neuromodulators (e.g., catecholamines) are believed to cause this low reliability by altering neurocognitive processes underlying memory formation. Using event-related functional magnetic resonance imaging, we investigated neural activity during memory formation in 44 young, healthy human participants while incidentally encoding emotionally neutral, complex scenes embedded in either a stressful or neutral context. We recorded event-related pupil dilation responses as an indirect index of phasic noradrenergic activity. Autonomic, endocrine, and psychological measures were acquired to validate stress manipulation. Acute stress during encoding led to a more liberal response bias (more hits and false alarms) when testing memory for the scenes 24 h later. The strength of this bias correlated negatively with pupil dilation responses and positively with stress-induced heart rate increases at encoding. Acute stress, moreover, reduced subsequent memory effects (SMEs; items later remembered vs forgotten) in hippocampus and midbrain, and in pupil dilation responses. The diminished SMEs indicate reduced selectivity and specificity in mnemonic processing during memory formation. This is in line with a model in which stress-induced catecholaminergic hyperactivation alters phasic neuromodulatory signaling in memory-related circuits, resulting in generalized (gist-based) processing at the cost of specificity. Thus, one may speculate that loss of specificity may yield less discrete memory representations at time of encoding, thereby causing a more liberal response bias when probing these memories.

  20. The influence of music-elicited emotions and relative pitch on absolute pitch memory for familiar melodies.

    PubMed

    Jakubowski, Kelly; Müllensiefen, Daniel

    2013-01-01

    Levitin's findings that nonmusicians could produce from memory the absolute pitches of self-selected pop songs have been widely cited in the music psychology literature. These findings suggest that latent absolute pitch (AP) memory may be a more widespread trait within the population than traditional AP labelling ability. However, it has been left unclear what factors may facilitate absolute pitch retention for familiar pieces of music. The aim of the present paper was to investigate factors that may contribute to latent AP memory using Levitin's sung production paradigm for AP memory and comparing results to the outcomes of a pitch labelling task, a relative pitch memory test, measures of music-induced emotions, and various measures of participants' musical backgrounds. Our results suggest that relative pitch memory and the quality and degree of music-elicited emotions impact on latent AP memory.

  1. Event-related EEG desynchronization and synchronization during an auditory memory task.

    PubMed

    Krause, C M; Lang, A H; Laine, M; Kuusisto, M; Pörn, B

    1996-04-01

    Event-related desynchronization (ERD) and synchronization (ERS) of the lower (8-10 Hz) and upper (10-12 Hz) alpha bands of background EEG were studied in 10 subjects during an auditory memory scanning paradigm. Each experimental trial started with the presentation of a visual warning signal, after which an auditory 4-vowel memory set was presented for memorization. Thereafter the probe, a fifth vowel, was presented and identified by the subject as belonging or not belonging to the memorized set. In 50% of the cases, the probe was among the previously presented memory set. The presentation of the memory set elicited a significant ERS in the both alpha frequency bands. In contrast, the presentation of the probe elicited a significant bilateral ERD in both alpha frequency bands studied. The results suggest that the ERD phenomenon is closely associated with higher cortical processes such as memory functions rather than with auditory stimulus processing per se. Event-related desynchronization provides a potentially valuable tool for studying cortical activity during cognitive processing in the auditory stimulus modality.

  2. Activation of NO-cGMP Signaling Rescues Age-Related Memory Impairment in Crickets

    PubMed Central

    Matsumoto, Yukihisa; Matsumoto, Chihiro S.; Takahashi, Toshihumi; Mizunami, Makoto

    2016-01-01

    Age-related memory impairment (AMI) is a common feature and a debilitating phenotype of brain aging in many animals. However, the molecular mechanisms underlying AMI are still largely unknown. The cricket Gryllus bimaculatus is a useful experimental animal for studying age-related changes in learning and memory capability; because the cricket has relatively short life-cycle and a high capability of olfactory learning and memory. Moreover, the molecular mechanisms underlying memory formation in crickets have been examined in detail. In the present study, we trained male crickets of different ages by multiple-trial olfactory conditioning to determine whether AMI occurs in crickets. Crickets 3 weeks after the final molt (3-week-old crickets) exhibited levels of retention similar to those of 1-week-old crickets at 30 min or 2 h after training; however they showed significantly decreased levels of 1-day retention, indicating AMI in long-term memory (LTM) but not in anesthesia-resistant memory (ARM) in olfactory learning of crickets. Furthermore, 3-week-old crickets injected with a nitric oxide (NO) donor, a cyclic GMP (cGMP) analog or a cyclic AMP (cAMP) analog into the hemolymph before conditioning exhibited a normal level of LTM, the same level as that in 1-week-old crickets. The rescue effect by NO donor or cGMP analog injection was absent when the crickets were injected after the conditioning. For the first time, an NO donor and a cGMP analog were found to antagonize the age-related impairment of LTM formation, suggesting that deterioration of NO synthase (NOS) or molecules upstream of NOS activation is involved in brain-aging processes. PMID:27616985

  3. Sex-Related Differences in the Effects of Sleep Habits on Verbal and Visuospatial Working Memory

    PubMed Central

    Nakagawa, Seishu; Takeuchi, Hikaru; Taki, Yasuyuki; Nouchi, Rui; Sekiguchi, Atsushi; Kotozaki, Yuka; Miyauchi, Carlos M.; Iizuka, Kunio; Yokoyama, Ryoichi; Shinada, Takamitsu; Yamamoto, Yuki; Hanawa, Sugiko; Araki, Tsuyoshi; Kunitoki, Keiko; Sassa, Yuko; Kawashima, Ryuta

    2016-01-01

    Poor sleep quality negatively affects memory performance, and working memory in particular. We investigated sleep habits related to sleep quality including sleep duration, daytime nap duration, nap frequency, and dream content recall frequency (DCRF). Declarative working memory can be subdivided into verbal working memory (VWM) and visuospatial working memory (VSWM). We hypothesized that sleep habits would have different effects on VWM and VSWM. To our knowledge, our study is the first to investigate differences between VWM and VSWM related to daytime nap duration, nap frequency, and DCRF. Furthermore, we tested the hypothesis that the effects of duration and frequency of daytime naps and DCRF on VWM and VSWM differed according to sex. We assessed 779 healthy right-handed individuals (434 males and 345 females; mean age: 20.7 ± 1.8 years) using a digit span forward and backward VWM task, a forward and backward VSWM task, and sleep habits scales. A correlation analysis was used to test the relationships between VWM capacity (VWMC) and VSWM capacity (VSWMC) scores and sleep duration, nap duration, nap frequency, and DCRF. Furthermore, multiple regression analyses were conducted to identify factors associated with VWMC and VSWMC scores and to identify sex-related differences. We found significant positive correlations between VSWMC and nap duration and DCRF, and between VWMC and sleep duration in all subjects. Furthermore, we found that working memory capacity (WMC) was positively correlated with nap duration in males and with sleep duration in females, and DCRF was positively correlated with VSWMC in females. Our finding of sex-related differences in the effects of sleep habits on WMC has not been reported previously. The associations between WMC and sleep habits differed according to sex because of differences in the underlying neural correlates of VWM and VSWM, and effectiveness of the sleep habits in males and females. PMID:27516751

  4. Sex-Related Differences in the Effects of Sleep Habits on Verbal and Visuospatial Working Memory.

    PubMed

    Nakagawa, Seishu; Takeuchi, Hikaru; Taki, Yasuyuki; Nouchi, Rui; Sekiguchi, Atsushi; Kotozaki, Yuka; Miyauchi, Carlos M; Iizuka, Kunio; Yokoyama, Ryoichi; Shinada, Takamitsu; Yamamoto, Yuki; Hanawa, Sugiko; Araki, Tsuyoshi; Kunitoki, Keiko; Sassa, Yuko; Kawashima, Ryuta

    2016-01-01

    Poor sleep quality negatively affects memory performance, and working memory in particular. We investigated sleep habits related to sleep quality including sleep duration, daytime nap duration, nap frequency, and dream content recall frequency (DCRF). Declarative working memory can be subdivided into verbal working memory (VWM) and visuospatial working memory (VSWM). We hypothesized that sleep habits would have different effects on VWM and VSWM. To our knowledge, our study is the first to investigate differences between VWM and VSWM related to daytime nap duration, nap frequency, and DCRF. Furthermore, we tested the hypothesis that the effects of duration and frequency of daytime naps and DCRF on VWM and VSWM differed according to sex. We assessed 779 healthy right-handed individuals (434 males and 345 females; mean age: 20.7 ± 1.8 years) using a digit span forward and backward VWM task, a forward and backward VSWM task, and sleep habits scales. A correlation analysis was used to test the relationships between VWM capacity (VWMC) and VSWM capacity (VSWMC) scores and sleep duration, nap duration, nap frequency, and DCRF. Furthermore, multiple regression analyses were conducted to identify factors associated with VWMC and VSWMC scores and to identify sex-related differences. We found significant positive correlations between VSWMC and nap duration and DCRF, and between VWMC and sleep duration in all subjects. Furthermore, we found that working memory capacity (WMC) was positively correlated with nap duration in males and with sleep duration in females, and DCRF was positively correlated with VSWMC in females. Our finding of sex-related differences in the effects of sleep habits on WMC has not been reported previously. The associations between WMC and sleep habits differed according to sex because of differences in the underlying neural correlates of VWM and VSWM, and effectiveness of the sleep habits in males and females.

  5. Cyclic nucleotide-gated channels, calmodulin, adenylyl cyclase, and calcium/calmodulin-dependent protein kinase II are required for late, but not early, long-term memory formation in the honeybee.

    PubMed

    Matsumoto, Yukihisa; Sandoz, Jean-Christophe; Devaud, Jean-Marc; Lormant, Flore; Mizunami, Makoto; Giurfa, Martin

    2014-04-16

    Memory is a dynamic process that allows encoding, storage, and retrieval of information acquired through individual experience. In the honeybee Apis mellifera, olfactory conditioning of the proboscis extension response (PER) has shown that besides short-term memory (STM) and mid-term memory (MTM), two phases of long-term memory (LTM) are formed upon multiple-trial conditioning: an early phase (e-LTM) which depends on translation from already available mRNA, and a late phase (l-LTM) which requires de novo transcription and translation. Here we combined olfactory PER conditioning and neuropharmacological inhibition and studied the involvement of the NO-cGMP pathway, and of specific molecules, such as cyclic nucleotide-gated channels (CNG), calmodulin (CaM), adenylyl cyclase (AC), and Ca(2+)/calmodulin-dependent protein kinase (CaMKII), in the formation of olfactory LTM in bees. We show that in addition to NO-cGMP and cAMP-PKA, CNG channels, CaM, AC, and CaMKII also participate in the formation of a l-LTM (72-h post-conditioning) that is specific for the learned odor. Importantly, the same molecules are dispensable for olfactory learning and for the formation of both MTM (in the minute and hour range) and e-LTM (24-h post-conditioning), thus suggesting that the signaling pathways leading to l-LTM or e-LTM involve different molecular actors.

  6. Working memory and language: skill-specific or domain-general relations to mathematics?

    PubMed

    Purpura, David J; Ganley, Colleen M

    2014-06-01

    Children's early mathematics skills develop in a cumulative fashion; foundational skills form a basis for the acquisition of later skills. However, non-mathematical factors such as working memory and language skills have also been linked to mathematical development at a broad level. Unfortunately, little research has been conducted to evaluate the specific relations of these two non-mathematical factors to individual aspects of early mathematics. Thus, the focus of this study was to determine whether working memory and language were related to only individual aspects of early mathematics or related to many components of early mathematics skills. A total of 199 4- to 6-year-old preschool and kindergarten children were assessed on a battery of early mathematics tasks as well as measures of working memory and language. Results indicated that working memory has a specific relation to only a few-but critically important-early mathematics skills and language has a broad relation to nearly all early mathematics skills.

  7. Memory for Melody: Infants Use a Relative Pitch Code

    ERIC Educational Resources Information Center

    Plantinga, Judy; Trainor, Laurel J.

    2005-01-01

    Pitch perception is fundamental to melody in music and prosody in speech. Unlike many animals, the vast majority of human adults store melodic information primarily in terms of relative not absolute pitch, and readily recognize a melody whether rendered in a high or a low pitch range. We show that at 6 months infants are also primarily relative…

  8. Long-term memory for calls of relatives in cotton-top tamarins (Saguinus oedipus).

    PubMed

    Matthews, Stephanie; Snowdon, Charles T

    2011-08-01

    Recognition of relatives is important for dispersing animals to avoid inbreeding and possibly for developing cooperative, reciprocal relationships between individuals after dispersal. We demonstrate under controlled captive conditions that cotton-top tamarins (Saguinus oedipus) have a long-term memory for long calls of relatives from which they had been separated for periods ranging from 4 to 55 months. Tamarins responded with lower levels of arousal behavior to playbacks of long calls from current mates and from separated relatives compared to calls of unfamiliar, unrelated tamarins. Four tamarins had been out of contact with relatives for more than 4 years and still showed recognition as evidenced by low levels of arousal. Results could not be explained in terms of proximity to former relatives. Long-term memory for vocal signatures of relatives is adaptive and may be much more common than has been demonstrated.

  9. Cognitive Association Formation in Episodic Memory: Evidence from Event-Related Potentials

    ERIC Educational Resources Information Center

    Kim, Alice S. N.; Vallesi, Antonino; Picton, Terence W.; Tulving, Endel

    2009-01-01

    The present study focused on the processes underlying cognitive association formation by investigating subsequent memory effects. Event-related potentials were recorded as participants studied pairs of words, presented one word at a time, for later recall. The findings showed that a frontal-positive late wave (LW), which occurred 1-1.6 s after the…

  10. The Role of Working Memory and Contextual Constraints in Children's Processing of Relative Clauses

    ERIC Educational Resources Information Center

    Wieghall, Anna R.; Altmann, Gerry T. M.

    2011-01-01

    An auditory sentence comprehension task investigated the extent to which the integration of contextual and structural cues was mediated by verbal memory span with 32 English-speaking six- to eight-year-old children. Spoken relative clause sentences were accompanied by visual context pictures which fully (depicting the actions described within the…

  11. Self-Regulatory Private Speech Relates to Children's Recall and Organization of Autobiographical Memories

    ERIC Educational Resources Information Center

    Al-Namlah, Abdulrahman S.; Meins, Elizabeth; Fernyhough, Charles

    2012-01-01

    We investigated relations between 4- and 7-year-olds' (N=58) autobiographical memory and their use of self-regulatory private speech in a non-mnemonic context (a cognitive planning task). Children's use of self-regulatory private speech during the planning task was associated with longer autobiographical narratives which included specific rather…

  12. Adapting to Changing Memory Retrieval Demands: Evidence from Event-Related Potentials

    ERIC Educational Resources Information Center

    Benoit, Roland G.; Werkle-Bergner, Markus; Mecklinger, Axel; Kray, Jutta

    2009-01-01

    This study investigated preparatory processes involved in adapting to changing episodic memory retrieval demands. Event-related potentials (ERPs) were recorded while participants performed a general old/new recognition task and a specific task that also required retrieval of perceptual details. The relevant task remained either constant or changed…

  13. Respecting Relations: Memory Access and Antecedent Retrieval in Incremental Sentence Processing

    ERIC Educational Resources Information Center

    Kush, Dave W.

    2013-01-01

    This dissertation uses the processing of anaphoric relations to probe how linguistic information is encoded in and retrieved from memory during real-time sentence comprehension. More specifically, the dissertation attempts to resolve a tension between the demands of a linguistic processor implemented in a general-purpose cognitive architecture and…

  14. New Rule Use Drives the Relation between Working Memory Capacity and Raven's Advanced Progressive Matrices

    ERIC Educational Resources Information Center

    Wiley, Jennifer; Jarosz, Andrew F.; Cushen, Patrick J.; Colflesh, Gregory J. H.

    2011-01-01

    The correlation between individual differences in working memory capacity and performance on the Raven's Advanced Progressive Matrices (RAPM) is well documented yet poorly understood. The present work proposes a new explanation: that the need to use a new combination of rules on RAPM problems drives the relation between performance and working…

  15. Age-Related Changes in Duration Reproduction: Involvement of Working Memory Processes

    ERIC Educational Resources Information Center

    Baudouin, Alexia; Vanneste, Sandrine; Pouthas, Viviane; Isingrini, Michel

    2006-01-01

    The aim of the present research was to study age-related changes in duration reproduction by differentiating the working memory processes underlying this time estimation task. We compared performances of young and elderly adults in a duration reproduction task performed in simple and concurrent task conditions. Participants were also administered…

  16. Trauma-Related Dissociation as a Factor Affecting Musicians' Memory for Music: Some Possible Solutions

    ERIC Educational Resources Information Center

    Swart, Inette; van Niekerk, Caroline; Hartman, Woltemade

    2010-01-01

    An investigation of the influence of trauma on musicians revealed concentration and memory problems as two of the most common symptoms hampering the performance of affected individuals. In many instances where the causes of these problems were related to trauma sequelae, these could clearly be linked to dissociative symptoms. The following…

  17. The Relations between Number Property Strategies, Working Memory, and Multiplication in Elementary Students

    ERIC Educational Resources Information Center

    Liu, Ru-De; Ding, Yi; Gao, Bing-Cheng; Zhang, Dake

    2015-01-01

    This study aimed to examine the relations among property strategies, working memory, and multiplication tasks with 101 Chinese fourth-grade students. Two multiplication property strategies (associative and distributive) were compared with no strategy and demonstrated differentiated effects on students' accuracy and reaction time. Associative…

  18. Mediating Effects of Working Memory in the Relation between Rapid Automatized Naming and Chinese Reading Comprehension

    ERIC Educational Resources Information Center

    Weng, Xiaoqian; Li, Guangze; Li, Rongbao

    2016-01-01

    This study examined the mediating role of working memory (WM) in the relation between rapid automatized naming (RAN) and Chinese reading comprehension. Three tasks assessing differentially visual and verbal components of WM were programmed by E-prime 2.0. Data collected from 55 Chinese college students were analyzed using correlations and…

  19. Event Memory and Suggestibility in Abused and Neglected Children: Trauma-Related Psychopathology and Cognitive Functioning

    ERIC Educational Resources Information Center

    Chae, Yoojin; Goodman, Gail S.; Eisen, Mitchell L.; Qin, Jianjian

    2011-01-01

    This study examined event memory and suggestibility in 3- to 16-year-olds involved in forensic investigations of child maltreatment. A total of 322 children were interviewed about a play activity with an unfamiliar adult. Comprehensive measures of individual differences in trauma-related psychopathology and cognitive functioning were administered.…

  20. Age-Related Differences in the Temporal Dynamics of Prospective Memory Retrieval: A Lifespan Approach

    ERIC Educational Resources Information Center

    Mattli, Florentina; Zollig, Jacqueline; West, Robert

    2011-01-01

    The efficiency of prospective memory (PM) typically increases from childhood to young adulthood and then decreases in later adulthood. The current study used event-related brain potentials (ERPs) to examine the development of the neural correlates of processes associated with the detection of a PM cue, switching from the ongoing activity to the…

  1. Mood, Memory and Movement: An Age-Related Neurodegenerative Complex?

    PubMed Central

    Granholm, Ann-Charlotte; Boger, Heather; Emborg, Marina E.

    2009-01-01

    The following review was constructed as a concept paper based on a recent workshop on neurodegenerative disease sponsored by the National Institute on Aging (NIA), the American Geriatric Society (AGS), and the John A. Hartford Foundation. The meeting was entitled “Thinking, moving and feeling: Common underlying mechanisms? 4th Annual Bedside-to-Bench Conference” and had the purpose to connect current basic and clinical findings on common brain-related alterations occurring with aging such as depression, movement disorders, and cognitive decline. Many prominent researchers expressed their opinion on aging and it was revealed that age-related brain dysfunction of any kind seems to share several risk factors and/or pathways. But can something be done to actively achieve “successful aging”? In this review, based largely on the workshop and current literature, we have summarized some of the current theories for depression, movement and cognitive impairment with aging, as well as potential preventive measures. We have also summarized the emerging need for relevant animal models and how these could be developed and utilized. PMID:20021382

  2. Intelligence related upper alpha desynchronization in a semantic memory task.

    PubMed

    Doppelmayr, M; Klimesch, W; Hödlmoser, K; Sauseng, P; Gruber, W

    2005-07-30

    Recent evidence shows that event-related (upper) alpha desynchronization (ERD) is related to cognitive performance. Several studies observed a positive, some a negative relationship. The latter finding, interpreted in terms of the neural efficiency hypothesis, suggests that good performance is associated with a more 'efficient', smaller extent of cortical activation. Other studies found that ERD increases with semantic processing demands and that this increase is larger for good performers. Studies supporting the neural efficiency hypothesis used tasks that do not specifically require semantic processing. Thus, we assume that the lack of semantic processing demands may at least in part be responsible for the reduced ERD. In the present study we measured ERD during a difficult verbal-semantic task. The findings demonstrate that during semantic processing, more intelligent (as compared to less intelligent) subjects exhibited a significantly larger upper alpha ERD over the left hemisphere. We conclude that more intelligent subjects exhibit a more extensive activation in a semantic processing system and suggest that divergent findings regarding the neural efficiency hypotheses are due to task specific differences in semantic processing demands.

  3. Trauma-related self-defining memories and future goals in Dissociative Identity Disorder.

    PubMed

    Huntjens, Rafaële J C; Wessel, Ineke; Ostafin, Brian D; Boelen, Paul A; Behrens, Friederike; van Minnen, Agnes

    2016-12-01

    This study examined the content of self-defining autobiographical memories in different identities in patients with Dissociative Identity Disorder (DID) and comparison groups of patients with PTSD, healthy controls, and DID simulators. Consistent with the DID trauma model, analyses of objective ratings showed that DID patients in trauma identities retrieved more negative and trauma-related self-defining memories than DID patients in avoidant identities. Inconsistent with the DID trauma model, DID patients' self-rated trauma-relatedness of self-defining memories and future life goals did not differ between trauma identities and trauma avoidant identities. That is, the DID patients did not seem to be "shut off" from their trauma while in their avoidant identity. Furthermore, DID patients in both identities reported a higher proportion of avoidance goals compared to PTSD patients, with the latter group scoring comparably to healthy controls. The simulators behaved according to the instructions to respond differently in each identity (i.e., to report memories and goals consistent with the identity tested). The discrepant task behavior by DID patients and simulators indicated that DID patients did not seem to intentionally produce the hypothesized differences in performance between identities. In conclusion, for patients with DID (i.e., in both identities) and patients with PTSD, trauma played a central role in the retrieval of self-defining memories and in the formulation of life goals.

  4. Medial temporal lobe coding of item and spatial information during relational binding in working memory.

    PubMed

    Libby, Laura A; Hannula, Deborah E; Ranganath, Charan

    2014-10-22

    Several models have proposed that different medial temporal lobe (MTL) regions represent different kinds of information in the service of long-term memory. For instance, it has been proposed that perirhinal cortex (PRC), parahippocampal cortex (PHC), and hippocampus differentially support long-term memory for item information, spatial context, and item-context relations present during an event, respectively. Recent evidence has indicated that, in addition to long-term memory, MTL subregions may similarly contribute to processes that support the retention of complex spatial arrangements of objects across short delays. Here, we used functional magnetic resonance imaging and multivoxel pattern similarity analysis to investigate the extent to which human MTL regions independently code for object and spatial information, as well as the conjunction of this information, during working memory encoding and active maintenance. Voxel activity patterns in PRC, temporopolar cortex, and amygdala carried information about individual objects, whereas activity patterns in the PHC and posterior hippocampus carried information about the configuration of spatial locations that was to be remembered. Additionally, the integrity of multivoxel patterns in the right anterior hippocampus across encoding and delay periods was predictive of accurate short-term memory for object-location relationships. These results are consistent with parallel processing of item and spatial context information by PRC and PHC, respectively, and the binding of item and context by the hippocampus.

  5. Medial Temporal Lobe Coding of Item and Spatial Information during Relational Binding in Working Memory

    PubMed Central

    Hannula, Deborah E.; Ranganath, Charan

    2014-01-01

    Several models have proposed that different medial temporal lobe (MTL) regions represent different kinds of information in the service of long-term memory. For instance, it has been proposed that perirhinal cortex (PRC), parahippocampal cortex (PHC), and hippocampus differentially support long-term memory for item information, spatial context, and item–context relations present during an event, respectively. Recent evidence has indicated that, in addition to long-term memory, MTL subregions may similarly contribute to processes that support the retention of complex spatial arrangements of objects across short delays. Here, we used functional magnetic resonance imaging and multivoxel pattern similarity analysis to investigate the extent to which human MTL regions independently code for object and spatial information, as well as the conjunction of this information, during working memory encoding and active maintenance. Voxel activity patterns in PRC, temporopolar cortex, and amygdala carried information about individual objects, whereas activity patterns in the PHC and posterior hippocampus carried information about the configuration of spatial locations that was to be remembered. Additionally, the integrity of multivoxel patterns in the right anterior hippocampus across encoding and delay periods was predictive of accurate short-term memory for object–location relationships. These results are consistent with parallel processing of item and spatial context information by PRC and PHC, respectively, and the binding of item and context by the hippocampus. PMID:25339737

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

    PubMed

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

    2014-10-22

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

  7. Relations among language exposure, phonological memory, and language development in Spanish-English bilingually developing 2-year-olds.

    PubMed

    Parra, Marisol; Hoff, Erika; Core, Cynthia

    2011-01-01

    The relation of phonological memory to language experience and development was investigated in 41 Spanish-English bilingual first language learners. The children's relative exposure to English and Spanish and their phonological memory for English- and Spanish-like nonwords were assessed at 22 months of age, and their productive vocabulary and grammar in both languages were assessed at 25 months of age. Phonological memory for English-like nonwords was highly correlated with that for Spanish-like nonwords, and each was related to vocabulary and grammar in both languages, suggesting a language-general component to phonological memory skill. In addition, there was evidence of language-specific benefits of language exposure to phonological memory skill and of language-specific benefits of phonological memory skill to language development.

  8. Competitive Semantic Memory Retrieval: Temporal Dynamics Revealed by Event-Related Potentials.

    PubMed

    Hellerstedt, Robin; Johansson, Mikael

    2016-01-01

    Memories compete for retrieval when they are related to a common retrieval cue. Previous research has shown that retrieval of a target memory may lead to subsequent retrieval-induced forgetting (RIF) of currently irrelevant competing memories. In the present study, we investigated the time course of competitive semantic retrieval and examined the neurocognitive mechanisms underlying RIF. We contrasted two theoretical accounts of RIF by examining a critical aspect of this memory phenomenon, namely the extent to which it depends on successful retrieval of the target memory. Participants first studied category-exemplar word-pairs (e.g. Fruit-Apple). Next, we recorded electrophysiological measures of brain activity while the participants performed a competitive semantic cued-recall task. In this task, the participants were provided with the studied categories but they were instructed to retrieve other unstudied exemplars (e.g. Fruit-Ma__?). We investigated the event-related potential (ERP) correlates of retrieval success by comparing ERPs from successful and failed retrieval trials. To isolate the ERP correlates of continuous retrieval attempts from the ERP correlates of retrieval success, we included an impossible retrieval condition, with incompletable word-stem cues (Drinks-Wy__) and compared it with a non-retrieval presentation baseline condition (Occupation-Dentist). The participants' memory for all the studied exemplars was tested in the final phase of the experiment. Taken together, the behavioural results suggest that RIF is independent of target retrieval. Beyond investigating the mechanisms underlying RIF, the present study also elucidates the temporal dynamics of semantic cued-recall by isolating the ERP correlates of retrieval attempt and retrieval success. The ERP results revealed that retrieval attempt is reflected in a late posterior negativity, possibly indicating construction of candidates for completing the word-stem cue and retrieval monitoring

  9. Developmental Links Between Children's Working Memory and their Social Relations with Teachers and Peers in the Early School Years.

    PubMed

    de Wilde, Amber; Koot, Hans M; van Lier, Pol A C

    2016-01-01

    This study assessed the developmental links between children's working memory development and their relations with teachers and peers across 2 years of kindergarten and early elementary school. Kindergarten and first grade children, N = 1109, 50% boys, were followed across 2 school-years. Children were assessed across 3 waves, in the fall and spring of the first school-year (within school-year), and finally in the spring of the second school-year. Working memory was assessed using a visuo-spatial working memory task. The developmental links between working memory and child-reported teacher-child relationship quality (warmth and conflict) and peer-nominated likeability and friendedness were assessed using autoregressive cross-lagged models. Lower working memory scores were related to increases in teacher-child conflict and decreases in teacher-child warmth one school-year later, in addition to decreases in likeability by peers within the same school-year. Conversely, teacher-child conflict was negatively associated with the development of working memory across the studied period. Path estimates between working memory and social relational factors were similar for boys and girls. Findings show developmental links between working memory and social-relational factors and vice versa. These results suggest that children's working memory development can be fostered through pro-social relations with teachers in early elementary school children.

  10. Relations among Language Exposure, Phonological Memory, and Language Development in Spanish-English Bilingually Developing 2-Year-Olds

    ERIC Educational Resources Information Center

    Parra, Marisol; Hoff, Erika; Core, Cynthia

    2011-01-01

    The relation of phonological memory to language experience and development was investigated in 41 Spanish-English bilingual first language learners. The children's relative exposure to English and Spanish and their phonological memory for English- and Spanish-like nonwords were assessed at 22 months of age, and their productive vocabulary and…

  11. Altered Hippocampal Transcript Profile Accompanies an Age-Related Spatial Memory Deficit in Mice

    ERIC Educational Resources Information Center

    Verbitsky, Miguel; Yonan, Amanda L.; Malleret, Gael; Kandel, Eric R.; Gilliam, T. Conrad; Pavlidis, Paul

    2004-01-01

    We have carried out a global survey of age-related changes in mRNA levels in the 57BL/6NIA mouse hippocampus and found a difference in the hippocampal gene expression profile between 2-month-old young mice and 15-month-old middle-aged mice correlated with an age-related cognitive deficit in hippocampal-based explicit memory formation. Middle-aged…

  12. Children's use of decomposition strategies mediates the visuospatial memory and arithmetic accuracy relation.

    PubMed

    Foley, Alana E; Vasilyeva, Marina; Laski, Elida V

    2016-12-14

    This study examined the mediating role of children's use of decomposition strategies in the relation between visuospatial memory (VSM) and arithmetic accuracy. Children (N = 78; Age M = 9.36) completed assessments of VSM, arithmetic strategies, and arithmetic accuracy. Consistent with previous findings, VSM predicted arithmetic accuracy in children. Extending previous findings, the current study showed that the relation between VSM and arithmetic performance was mediated by the frequency of children's use of decomposition strategies. Identifying the role of arithmetic strategies in this relation has implications for increasing the math performance of children with lower VSM. Statement of contribution What is already known on this subject? The link between children's visuospatial working memory and arithmetic accuracy is well documented. Frequency of decomposition strategy use is positively related to children's arithmetic accuracy. Children's spatial skill positively predicts the frequency with which they use decomposition. What does this study add? Short-term visuospatial memory (VSM) positively relates to the frequency of children's decomposition use. Decomposition use mediates the relation between short-term VSM and arithmetic accuracy. Children with limited short-term VSM may struggle to use decomposition, decreasing accuracy.

  13. Unifying Gate Synthesis and Magic State Distillation

    NASA Astrophysics Data System (ADS)

    Campbell, Earl T.; Howard, Mark

    2017-02-01

    The leading paradigm for performing a computation on quantum memories can be encapsulated as distill-then-synthesize. Initially, one performs several rounds of distillation to create high-fidelity magic states that provide one good T gate, an essential quantum logic gate. Subsequently, gate synthesis intersperses many T gates with Clifford gates to realize a desired circuit. We introduce a unified framework that implements one round of distillation and multiquibit gate synthesis in a single step. Typically, our method uses the same number of T gates as conventional synthesis but with the added benefit of quadratic error suppression. Because of this, one less round of magic state distillation needs to be performed, leading to significant resource savings.

  14. Verbal memory functioning moderates psychotherapy treatment response for PTSD-Related nightmares.

    PubMed

    Scott, J Cobb; Harb, Gerlinde; Brownlow, Janeese A; Greene, Jennifer; Gur, Ruben C; Ross, Richard J

    2017-04-01

    Posttraumatic stress disorder (PTSD) is associated with cognitive deficits in attention, executive control, and memory, although few studies have investigated the relevance of cognitive difficulties for treatment outcomes. We examined whether cognitive functioning and history of traumatic brain injury (TBI) were associated with response to cognitive-behavioral therapy (CBT) for PTSD-related sleep problems. In a randomized controlled trial of Imagery Rehearsal (IR) added to components of CBT for Insomnia (IR + cCBT-I) compared to cCBT-I alone for PTSD-related recurrent nightmares, 94 U.S. veterans completed a battery of cognitive tests. TBI was assessed via structured clinical interview. Mixed-effects models examined main effects of cognitive functioning and interactions with time on primary sleep and nightmare outcomes. Significant verbal immediate memory by time interactions were found for nightmare distress, nightmare frequency, and sleep quality, even after controlling for overall cognitive performance and depression. TBI exhibited main effects on outcomes but no interactions with time. Findings indicated that individuals with lower verbal memory performance were less likely to respond to treatment across two sleep interventions. Veterans with TBI displayed greater symptoms but no altered trajectories of treatment response. Together with prior literature, findings suggest that verbal memory functioning may be important to consider in PTSD treatment implementation.

  15. Evidence for Attentional Gradient in the Serial Position Memory Curve from Event-related Potentials

    PubMed Central

    Azizian, Allen; Polich, John

    2009-01-01

    The occurrence of primacy versus recency effects in free recall is suggested to reflect either two distinct memory systems, or the operation of a single system that is modulated by allocation of attention and less vulnerable to interference. Behavioral and event-related brain potential (ERPs) measures were used to investigate the encoding substrates of the serial position curve and subsequent recall in young adults. Participants were instructed to remember lists of words consisting of 12 common nouns each presented once every 1.5 sec, with a recall signal following the last word to indicate that all remembered items should be written on paper. This procedure was repeated for 20 different word lists. Both performance and late ERP amplitudes reflected classic recall serial position effects. Greater recall and larger late positive component amplitudes were obtained for the primacy and recency items, with less recall and smaller amplitudes for the middle words. The late positive component was larger for recalled compared to unrecalled primacy items, but it did not differ between memory performance outcomes for the recency items. The close relationship between the enhanced amplitude and primacy retrieval supports the view that this positive component reflects one of a process series related to attentional gradient and encoding of events for storage in memory. Recency effects appear to index operations determined by the anticipation of the last stimulus presentation, which occurred for both recalled and unrecalled memory items. Theoretical implications are discussed. PMID:17892393

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

    PubMed

    Bauch, Eva M; Bunzeck, Nico

    2015-09-01

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

  17. Impaired decision making and delayed memory are related with anxiety and depressive symptoms in acromegaly.

    PubMed

    Crespo, Iris; Santos, Alicia; Valassi, Elena; Pires, Patricia; Webb, Susan M; Resmini, Eugenia

    2015-12-01

    Evaluation of cognitive function in acromegaly has revealed contradictory findings; some studies report normal cognition in patients with long-term cured acromegaly, while others show attention and memory deficits. Moreover, the presence of affective disorders in these patients is common. Our aim was to evaluate memory and decision making in acromegalic patients and explore their relationship with affective disorders like anxiety and depressive symptoms. Thirty-one patients with acromegaly (mean age 49.5 ± 8.5 years, 14 females and 17 males) and thirty-one healthy controls participated in this study. The Iowa Gambling Task (IGT), Rey Auditory Verbal Learning Test, State-Trait Anxiety Inventory, and Beck Depression Inventory-II (BDI-II) were used to evaluate decision making, verbal memory, anxiety, and depressive symptoms, respectively. Acromegalic patients showed impairments in delayed verbal memory (p < 0.05) and more anxiety and depressive symptoms (p < 0.05) than controls. In the IGT, acromegalic patients presented an altered decision-making strategy compared to controls, choosing a lower number of the safer cards (p < 0.05) and higher number of the riskier cards (p < 0.05). Moreover, multiple correlations between anxiety and depressive symptoms and performance in memory and decision making were found. Impaired delayed memory and decision making observed in acromegalic patients are related to anxiety and depressive symptoms. Providing emotional support to the patients could improve their cognitive function. A key clinical application of this research is the finding that depressive symptoms and anxiety are essentially modifiable factors.

  18. Greater memory impairment in dementing females than males relative to sex-matched healthy controls.

    PubMed

    Gale, Shawn D; Baxter, Leslie; Thompson, Juliann

    2016-01-01

    Previously we demonstrated sex differences in episodic memory in healthy elderly and suggested that normative data be separated by sex. The present study extended the exploration of sex differences on memory measures into two clinical populations, mild cognitive impairment (MCI) and Alzheimer's disease (AD). Seventy-six subjects with MCI and 101 subjects with AD diagnosed by a multidisciplinary team were included. These two groups were also compared to a group of 177 healthy elderly control participants. Sex differences on the Rey Auditory Verbal Learning Test (RAVLT; total and delayed recall) raw scores and Brief Visuospatial Memory Test-Revised (BVMT-R) were demonstrated within the healthy but not the MCI or AD groups. Calculating z scores by sex for both dementing groups based on the healthy controls suggested a larger performance gap between healthy and dementing women than between healthy and dementing men. MCI females were on average 0.48 standard deviations lower for total verbal learning compared to healthy female controls than were MCI males when compared to healthy male controls. For verbal delayed recall the gap was even larger (SD = 1.09). Similarly, on the BVMT-R, a measure of visual memory, the difference was 0.60 standard deviations for total visual learning and 0.99 standard deviations for delayed recall. This same sex difference, with females showing greater impairment compared to the controls group than did the males, was also present within the AD group. The greater memory impairment in dementing females rather than males when compared to sex-matched healthy controls was unlikely to be due to more severe illness since females performed equivalently to males on the Clinical Dementia Rating Scale, Mini-Mental Status Examination, and Dementia Rating Scale, and were also similar for age, education, and apolipoprotein status. The present study suggested relatively greater memory impairment in females with MCI or AD than in controls.

  19. Anandamide, an endogenous cannabinoid, inhibits Shaker-related voltage-gated K+ channels.

    PubMed

    Poling, J S; Rogawski, M A; Salem, N; Vicini, S

    1996-01-01

    Anandamide has been identified in porcine brain as an endogenous cannabinoid receptor ligand and is believed to be a counterpart to the psychoactive component of marijuana, delta 9-tetrahydrocannabinol (delta 9-THC). Here we report that anandamide directly inhibits (IC50, 2.7 muM) Shaker-related Kv1.2 K+ channels that are found ubiquitously in the mammalian brain. Delta 9-THC also inhibited Kv1.2 channels with comparable potency (IC50, 2.4 muM), as did several N-acyl-ethanolamides with cannabinoid receptor binding activity. Potassium current inhibition occurred through a pertussis toxin-insensitive mechanism and was not prevented by the cannabinoid receptor antagonist SR141716A. Utilizing excised patches of Kv1.2 channel-rich membrane as a rapid and sensitive bioassay, we found that phospholipase D stimulated the release of an endogenous anandamide-like K+ channel blocker from rat brain slices. Structure-activity studies were consistent with the possibility that the released blocker was either anandamide or another N-acyl-ethanolamide.

  20. Aging-associated formaldehyde-induced norepinephrine deficiency contributes to age-related memory decline.

    PubMed

    Mei, Yufei; Jiang, Chun; Wan, You; Lv, Jihui; Jia, Jianping; Wang, Xiaomin; Yang, Xu; Tong, Zhiqian

    2015-08-01

    A norepinephrine (NE) deficiency has been observed in aged rats and in patients with Alzheimer's disease and is thought to cause cognitive disorder. Which endogenous factor induces NE depletion, however, is largely unknown. In this study, we investigated the effects of aging-associated formaldehyde (FA) on the inactivation of NE in vitro and in vivo, and on memory behaviors in rodents. The results showed that age-related DNA demethylation led to hippocampal FA accumulation, and when this occurred, the hippocampal NE content was reduced in healthy male rats of different ages. Furthermore, biochemical analysis revealed that FA rapidly inactivated NE in vitro and that an intrahippocampal injection of FA markedly reduced hippocampal NE levels in healthy adult rats. Unexpectedly, an injection of FA (at a pathological level) or 6-hydroxydopamine (6-OHDA, a NE depletor) can mimic age-related NE deficiency, long-term potentiation (LTP) impairments, and spatial memory deficits in healthy adult rats. Conversely, an injection of NE reversed age-related deficits in both LTP and memory in aged rats. In agreement with the above results, the senescence-accelerated prone 8 (SAMP8) mice also exhibited a severe deficit in LTP and memory associated with a more severe NE deficiency and FA accumulation, when compared with the age-matched, senescence-resistant 1 (SAMR1) mice. Injection of resveratrol (a natural FA scavenger) or NE into SAMP8 mice reversed FA accumulation and NE deficiency and restored the magnitude of LTP and memory. Collectively, these findings suggest that accumulated FA is a critical endogenous factor for aging-associated NE depletion and cognitive decline.

  1. Parallel prefrontal pathways reach distinct excitatory and inhibitory systems in memory-related rhinal cortices

    PubMed Central

    Bunce, Jamie G.; Zikopoulos, Basilis; Feinberg, Marcia; Barbas, Helen

    2013-01-01

    To investigate how prefrontal cortices impinge on medial temporal cortices we labeled pathways from the anterior cingulate cortex (ACC) and posterior orbitofrontal cortex (pOFC) in rhesus monkeys to compare their relationship with excitatory and inhibitory systems in rhinal cortices. The ACC pathway terminated mostly in areas 28 and 35 with a high proportion of large terminals, whereas the pOFC pathway terminated mostly through small terminals in area 36 and sparsely in areas 28 and 35. Both pathways terminated in all layers. Simultaneous labeling of pathways and distinct neurochemical classes of inhibitory neurons, followed by analyses of appositions of presynaptic and postsynaptic fluorescent signal, or synapses, showed overall predominant association with spines of putative excitatory neurons, but also significant interactions with presumed inhibitory neurons labeled for calretinin, calbindin or parvalbumin. In the upper layers of areas 28 and 35 the ACC pathway was associated with dendrites of neurons labeled with calretinin, which are thought to disinhibit neighboring excitatory neurons, suggesting facilitated hippocampal access. In contrast, in area 36 pOFC axons were associated with dendrites of calbindin neurons, which are poised to reduce noise and enhance signal. In the deep layers, both pathways innervated mostly dendrites of parvalbumin neurons, which strongly inhibit neighboring excitatory neurons, suggesting gating of hippocampal output to other cortices. These findings suggest that the ACC, associated with attention and context, and the pOFC, associated with emotional valuation, have distinct contributions to memory in rhinal cortices, in processes that are disrupted in psychiatric diseases. PMID:23839697

  2. Cognition- and memory-related ERD/ERS responses in the auditory stimulus modality.

    PubMed

    Krause, Christina M

    2006-01-01

    In the year 1994, Krause et al. published an initial report of acoustically elicited electroencephalogram (EEG) event-related desynchronization (ERD)/ event-related synchronization (ERS) responses. Later, Krause et al. reported of distinct ERD/ERS responses during an auditory memory task: the encoding of acoustic material elicited alpha-frequency ERS whereas retrieval or recognition of the same stimulus material evoked alpha ERD. The research group of Krause and co-workers has published several reports on acoustically evoked ERD/ERS responses utilizing various cognitive tasks and diverse stimuli. Recently, also clinical studies have been initiated. This chapter reviews, summarizes, and discusses the findings on cognition- and memory-related ERD/ERS responses specifically in the auditory stimulus modality.

  3. Age-related slowing of memory retrieval: Contributions of perceptual speed and cerebral white matter integrity

    PubMed Central

    Bucur, Barbara; Madden, David J.; Spaniol, Julia; Provenzale, James M.; Cabeza, Roberto; White, Leonard E.; Huettel, Scott A.

    2007-01-01

    Previous research suggests that, in reaction time (RT) measures of episodic memory retrieval, the unique effects of adult age are relatively small compared to the effects aging shares with more elementary abilities such as perceptual speed. Little is known, however, regarding the mechanisms of perceptual speed. We used diffusion tensor imaging (DTI) to test the hypothesis that white matter integrity, as indexed by fractional anisotropy (FA), serves as one mechanism of perceptual slowing in episodic memory retrieval. Results indicated that declines in FA in the pericallosal frontal region and in the genu of the corpus callosum, but not in other regions, mediated the relationship between perceptual speed and episodic retrieval RT. This relation held, though to a different degree, for both hits and correct rejections. These findings suggest that white matter integrity in prefrontal regions is one mechanism underlying the relation between individual differences in perceptual speed and episodic retrieval. PMID:17383774

  4. Hearing Loss Is Negatively Related to Episodic and Semantic Long-Term Memory but Not to Short-Term Memory

    ERIC Educational Resources Information Center

    Ronnberg, Jerker; Danielsson, Henrik; Rudner, Mary; Arlinger, Stig; Sternang, Ola; Wahlin, Ake; Nilsson, Lars-Goran

    2011-01-01

    Purpose: To test the relationship between degree of hearing loss and different memory systems in hearing aid users. Method: Structural equation modeling (SEM) was used to study the relationship between auditory and visual acuity and different cognitive and memory functions in an age-hetereogenous subsample of 160 hearing aid users without…

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

    PubMed

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

    2013-10-15

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

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

    PubMed Central

    Giovanello, Kelly S.; Guskiewicz, Kevin M.

    2013-01-01

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

  7. Investigation of field induced trapping on floating gates

    NASA Technical Reports Server (NTRS)

    Gosney, W. M.

    1975-01-01

    The development of a technology for building electrically alterable read only memories (EAROMs) or reprogrammable read only memories (RPROMs) using a single level metal gate p channel MOS process with all conventional processing steps is outlined. Nonvolatile storage of data is achieved by the use of charged floating gate electrodes. The floating gates are charged by avalanche injection of hot electrodes through gate oxide, and discharged by avalanche injection of hot holes through gate oxide. Three extra diffusion and patterning steps are all that is required to convert a standard p channel MOS process into a nonvolatile memory process. For identification, this nonvolatile memory technology was given the descriptive acronym DIFMOS which stands for Dual Injector, Floating gate MOS.

  8. A low cortisol response to acute stress is related to worse basal memory performance in older people

    PubMed Central

    Almela, Mercedes; Hidalgo, Vanesa; van der Meij, Leander; Pulopulos, Matías M.; Villada, Carolina; Salvador, Alicia

    2014-01-01

    Age-related memory decline has been associated with a faulty regulation of the hypothalamus-pituitary-adrenal axis (HPA-axis). The aim of this study was to investigate whether the magnitude of the stress-induced cortisol increase is related to memory performance when memory is measured in non-stressful conditions. To do so, declarative and working memory performance were measured in 31 men and 35 women between 55 and 77 years of age. On a different day, the magnitude of their cortisol response to acute psychosocial stress was measured. The relationship between the cortisol response and memory performance was U shaped: a low cortisol response to stress was related to poorer declarative and working memory performance, whereas those who did not increase their cortisol levels and those who had the largest cortisol increase had better declarative and working memory capabilities. Sex did not moderate these relationships. These results suggest that a low cortisol response to stress could reflect a defective HPA-axis response to stressors that is accompanied by poorer memory performance. Conversely, a high cortisol response seems to reflect a correct functioning of the HPA-axis and may protect against memory deficits in the later stages of human life. PMID:25076903

  9. A Four–Component Model of Age–Related Memory Change

    PubMed Central

    Healey, M. Karl; Kahana, Michael J.

    2015-01-01

    We develop a novel, computationally explicit, theory of age–related memory change within the framework of the context maintenance and retrieval (CMR2) model of memory search. We introduce a set of benchmark findings from the free recall and recognition tasks that includes aspects of memory performance that show both age-related stability and decline. We test aging theories by lesioning the corresponding mechanisms in a model fit to younger adult free recall data. When effects are considered in isolation, many theories provide an adequate account, but when all effects are considered simultaneously, the existing theories fail. We develop a novel theory by fitting the full model (i.e., allowing all parameters to vary) to individual participants and comparing the distributions of parameter values for older and younger adults. This theory implicates four components: 1) the ability to sustain attention across an encoding episode, 2) the ability to retrieve contextual representations for use as retrieval cues, 3) the ability to monitor retrievals and reject intrusions, and 4) the level of noise in retrieval competitions. We extend CMR2 to simulate a recognition memory task using the same mechanisms the free recall model uses to reject intrusions. Without fitting any additional parameters, the four–component theory that accounts for age differences in free recall predicts the magnitude of age differences in recognition memory accuracy. Confirming a prediction of the model, free recall intrusion rates correlate positively with recognition false alarm rates. Thus we provide a four–component theory of a complex pattern of age differences across two key laboratory tasks. PMID:26501233

  10. Encoding of faces and objects into visual working memory: an event-related brain potential study.

    PubMed

    Meinhardt-Injac, Bozana; Persike, Malte; Berti, Stefan

    2013-09-11

    Visual working memory (VWM) is an important prerequisite for cognitive functions, but little is known on whether the general perceptual processing advantage for faces also applies to VWM processes. The aim of the present study was (a) to test whether there is a general advantage for face stimuli in VWM and (b) to unravel whether this advantage is related to early sensory processing stages. To address these questions, we compared encoding of faces and complex nonfacial objects into VWM within a combined behavioral and event-related brain potential (ERP) study. In detail, we tested whether the N170 ERP component - which is associated with face-specific holistic processing - is affected by memory load for faces or whether it might be involved in WM encoding of any complex object. Participants performed a same-different task with either face or watch stimuli and with two different levels of memory load. Behavioral measures show an advantage for faces on the level of VWM, mirrored in higher estimated VWM capacity (i.e. Cowan's K) for faces compared with watches. In the ERP, the N170 amplitude was enhanced for faces compared with watches. However, the N170 was not modulated by working memory load either for faces or for watches. In contrast, the P3b component was affected by memory load irrespective of the stimulus category. Taken together, the results suggest that the VWM advantage for faces is not reflected at the sensory stages of stimulus processing, but rather at later higher-level processes as reflected by the P3b component.

  11. Working memory load-related electroencephalographic parameters can differentiate progressive from stable mild cognitive impairment.

    PubMed

    Missonnier, P; Deiber, M-P; Gold, G; Herrmann, F R; Millet, P; Michon, A; Fazio-Costa, L; Ibañez, V; Giannakopoulos, P

    2007-12-05

    Recent studies described several changes of endogenous event-related potentials (ERP) and brain rhythm synchronization during memory activation in patients with Alzheimer's disease (AD). To examine whether memory-related EEG parameters may predict cognitive decline in mild cognitive impairment (MCI), we assessed P200 and N200 latencies as well as beta event-related synchronization (ERS) in 16 elderly controls (EC), 29 MCI cases and 10 patients with AD during the successful performance of a pure attentional detection task as compared with a highly working memory demanding two-back task. At 1 year follow-up, 16 MCI patients showed progressive cognitive decline (PMCI) and 13 remained stable (SMCI). Both P200 and N200 latencies in the two-back task were longer in PMCI and AD cases compared with EC and SMCI cases. During the interval 1000 ms to 1700 ms after stimulus, beta ERS at parietal electrodes was of lower amplitude in PMCI and AD compared with EC and SMCI cases. Univariate models showed that P200, N200 and log% beta values were significantly related to the SMCI/PMCI distinction with areas under the receiver operating characteristic curve of 0.93, 0.78 and 0.72, respectively. The combination of all three EEG hallmarks was the stronger predictor of MCI deterioration with 90% of correctly classified MCI cases. Our data reveal that PMCI and clinically overt AD share the same pattern of working memory-related EEG activation characterized by increased P200-N200 latencies and decreased beta ERS. They also show that P200 latency during the two-back task may be a simple and promising EEG marker of rapid cognitive decline in MCI.

  12. Aging and associative recognition: A view from the DRYAD model of age-related memory deficits.

    PubMed

    Benjamin, Aaron S

    2016-02-01

    How do we best characterize the memory deficits that accompany aging? A popular hypothesis, articulated originally by Naveh-Benjamin (2000) and reviewed in the accompanying article by Smyth and Naveh-Benjamin (2016), suggests that older adults are selectively deficient in establishing associations between to-be-learned memoranda and as a result have deficits in memory for sources or contexts. An alternative proposal, called density of representations yields age-related deficits (DRYAD) and outlined in recent articles by Benjamin (2010) and colleagues (Benjamin, Diaz, Matzen, & Johnson, 2012), attributes disproportionate deficits in memory to a global, rather than a selective, deficit of memory. In an attempt to adjudicate between these competing positions, Smyth and Naveh-Benjamin (2016) discussed 2 sets of experimental data that they claim speak against the global deficit model. Here I review some general principles of how the global-deficit view is applied to experimental paradigms and demonstrate that even a simplified form of DRYAD can comfortably accommodate the critical findings cited by Smyth and Naveh-Benjamin. I also evaluate aspects of their results that may be problematic for DRYAD and describe ways in which DRYAD's account of associative recognition can be falsified. I end with a discussion of the complementary strengths and weaknesses of the 2 approaches and consider ways in which the associative deficit hypothesis and DRYAD might work more profitably together than apart.

  13. Semantic False Memories In The Form Of Derived Relational Intrusions Following Training

    PubMed Central

    Guinther, Paul M; Dougher, Michael J

    2010-01-01

    Contemporary behavior analytic research is making headway in characterizing memory phenomena that typically have been characterized by cognitive models, and the current study extends this development by producing “false memories” in the form of functional equivalence responding. A match-to-sample training procedure was administered in order to encourage participants to treat groups of unrelated English words as being interchangeable. Following training, participants were presented with a list of words from within one of the groups for a free recall test and a recognition test. Results showed that participants were more likely to falsely recall and recognize words that had been assigned to the same group as the list words during prior training, relative to words not assigned to the same group and relative to words that co-occurred with list words. These results indicate that semantic relatedness can be experimentally manipulated in order to produce specific false memories. PMID:21119849

  14. Who, when, and where? Age-related differences on a new memory test

    PubMed Central

    Sumida, Catherine A.; Holden, Heather M.; Van Etten, Emily J.; Wagner, Gabrielle M.; Hileman, Jacob D.

    2016-01-01

    Our study examined age-related differences on a new memory test assessing memory for “who,” “when,” and “where,” and associations among these elements. Participants were required to remember a sequence of pictures of different faces paired with different places. Older adults remembered significantly fewer correct face–place pairs in the correct sequence compared with young adults. Correlation analyses with standardized neuropsychological tests provide preliminary evidence for construct validity. Our results offer insight into age-related changes in the ability to remember associations between people and places at different points in time using a portable test that can be administered rapidly in various settings. PMID:26670185

  15. Gulliver meets Descartes: early modern concepts of age-related memory loss.

    PubMed

    Schäfer, Daniel

    2003-03-01

    Age-related memory loss was a marginal issue in medical discussions during early modern times and until well into the second half of the 17th century. There are many possible explanations: the lack of similar traditions in antiquity and in the Middle Ages, insufficient physiological and morphological knowledge of the brain, and the underlying conflict between idealistic and materialistic perspectives on the functions of the soul and the conditions of these in old age. After these boundaries had been pushed back by the influence of Cartesianism and Iatromechanism, the problem of age-related memory loss was increasingly regarded as a physical illness and began to receive more attention. This trend first occurred in medicine, before spreading to the literary world, where the novel "Gulliver's Travels" is one clear and famous example.

  16. 16. DETAIL VIEW OF SUBMERSIBLE TAINTER GATE, SHOWING GATE, GATE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    16. DETAIL VIEW OF SUBMERSIBLE TAINTER GATE, SHOWING GATE, GATE ARM, TRUNNION PIN AND PIER, LOOKING NORTHEAST - Upper Mississippi River 9-Foot Channel, Lock & Dam No. 8, On Mississippi River near Houston County, MN, Genoa, Vernon County, WI

  17. 18. DETAIL VIEW OF NONSUBMERSIBLE TAINTER GATE, SHOWING GATES, GATE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    18. DETAIL VIEW OF NON-SUBMERSIBLE TAINTER GATE, SHOWING GATES, GATE ARMS, PIERS AND DAM BRIDGE, LOOKING SOUTHEAST - Upper Mississippi River 9-Foot Channel, Lock & Dam No. 9, Lynxville, Crawford County, WI

  18. Voltage-clamp predictions by gompertz kinetics model relating squid-axon Na+-gating and ionic currents.

    PubMed

    Easton, Dexter M

    2005-10-01

    Gompertz kinetics is a simple, realistic, accurate, and computationally parsimonious alternative for prediction of macroscopic changes in Na+ conductance during voltage clamp. Conductance delay and time course depend on initial amplitudes and decay rates of surrogates for the macroscopic gating currents. The model is tested by the fit to published data of other authors. The proposed physical basis for the model is that membrane potential perturbation triggers motion of charged "gating" components of the axon membrane at rapid (activating) and at slow (inactivating) rates. The resulting distortion increases and more slowly diminishes the probability that conduction channels will be open.

  19. Effects of Prenatal Exposure to Nicotine on Working Memory, Activity, Sensory Gating, and Dopamine Receptor Binding in Adolescent and Adult Male and Female Rats

    DTIC Science & Technology

    1999-01-08

    by female rats during agonistic interactions : Effects of morphine and naltrexone. Psychopharmacology. 114, 441-448. Hardy, J.B., & Mellits, ED...Rakic and colleagues in primates. Particularly of interest in spatial working memory is the connection of the hippocampus with the prefrontal cortex...Early work of Olton and others have identified the key role that the hippocampus plays in spatial memory processing (Olton, 1983; Olton et aI., 1979a

  20. Caffeine and related compounds block inhibitory amino acid-gated Cl- currents in freshly dissociated rat hippocampal neurones.

    PubMed Central

    Uneyama, H.; Harata, N.; Akaike, N.

    1993-01-01

    1. The effects of caffeine and related compounds on responses mediated by inhibitory amino acids were investigated in freshly dissociated rat hippocampal pyramidal neurones by conventional and nystatin perforated patch-clamp techniques. 2. Glycine and gamma-aminobutyric acid (GABA) evoked Cl- currents in hippocampal neurones. The half-maximum effective concentrations (EC50) of glycine and GABA were 8.5 x 10(-5) and 5 x 10(-6) M, respectively. 3. Caffeine reversibly inhibited both 10(-4) M glycine- and 10(-5) M GABA-induced Cl-currents in a concentration-dependent manner. The half-maximum inhibitory concentrations (IC50) of caffeine were 4.5 x 10(-4) M for the glycine response and 3.6 x 10(-3) M for the GABA response. 4. Caffeine shifted the concentration-response curve of IGly to the right without affecting the maximum response. 5. The inhibitory action of caffeine did not show voltage-dependency. 6. The blocking action of caffeine was not affected by intracellular perfusion with 5 mM BAPTA or by pretreatment with the protein kinase A inhibitor, H-8. This excludes the participation of Ca2+ or cyclic AMP in the inhibitory action of caffeine. 7. Caffeine failed to inhibit the augmentations of aspartate- and N-methyl-D-aspartate (NMDA) -gated current by glycine, suggesting that caffeine has no effect on the allosteric glycine binding site on the NMDA receptor. 8. The inhibitory effects of some xanthine derivatives on IGly were compared. The inhibitory potency of those compounds on IGly was in the order of pentoxifylline > theophylline > or = caffeine > paraxanthine > IBMX > or = theobromine > dyphylline. Xanthine had no effect.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7689394

  1. How Working Memory Relates to Children's Reading Comprehension: The Importance of Domain-Specificity in Storage and Processing

    ERIC Educational Resources Information Center

    Nouwens, Suzan; Groen, Margriet A.; Verhoeven, Ludo

    2017-01-01

    Working memory is considered a well-established predictor of individual variation in reading comprehension in children and adults. However, how storage and processing capacities of working memory in both the phonological and semantic domain relate to reading comprehension is still unclear. In the current study, we investigated the contribution of…

  2. The Relation between the Working Memory Skills of Sign Language Interpreters and the Quality of Their Interpretations

    ERIC Educational Resources Information Center

    Van Dijk, Rick; Christoffels, Ingrid; Postma, Albert; Hermans, Daan

    2012-01-01

    In two experiments we investigated the relationship between the working memory skills of sign language interpreters and the quality of their interpretations. In Experiment 1, we found that scores on 3-back tasks with signs and words were not related to the quality of interpreted narratives. In Experiment 2, we found that memory span scores for…

  3. Sex-Related Hemispheric Lateralization of Amygdala Function in Emotionally Influenced Memory: An fMRI Investigation

    ERIC Educational Resources Information Center

    Cahill, Larry; Uncapher, Melina; Kilpatrick, Lisa; Alkire, Mike T.; Turner, Jessica

    2004-01-01

    The amygdala appears necessary for enhanced long-term memory associated with emotionally arousing events. Recent brain imaging investigations support this view and indicate a sex-related hemispheric lateralization exists in the amygdala relationship to memory for emotional material. This study confirms and further explores this finding. Healthy…

  4. Comparing the Contribution of Two Tests of Working Memory to Reading in Relation to Phonological Awareness and Rapid Naming Speed

    ERIC Educational Resources Information Center

    Georgiou, George K.; Das, J. P.; Hayward, Denyse V.

    2008-01-01

    The purpose of this study was to compare the contribution of two different versions of working memory to word reading and reading comprehension in relation to phonological awareness and rapid naming speed. Fifty children were administered two measures of working memory, namely an adaptation of the Daneman and Carpenter sentence span task and…

  5. No evidence of relation between working memory and perception of interrupted speech in young adults.

    PubMed

    Nagaraj, Naveen K; Knapp, Andrea N

    2015-08-01

    Understanding interrupted speech requires top-down linguistic and cognitive restoration mechanisms. To investigate the relation between working memory (WM) and perception of interrupted speech, 20 young adults were asked to recognize sentences interrupted at 2 Hz, 8 Hz, and a combination of 2 and 8 Hz. WM was measured using automated reading and operation span tasks. Interestingly, the results presented here revealed no statistical relation between any of the interrupted speech recognition scores and WM scores. This finding is in agreement with previous findings that suggest greater reliance on linguistic factors relative to cognitive factors during perception of interrupted speech.

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

    PubMed

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

    2014-04-01

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

  7. The enhancement of stress-related memory by glucocorticoids depends on synapsin-Ia/Ib

    PubMed Central

    Revest, J-M; Kaouane, N; Mondin, M; Le Roux, A; Rougé-Pont, F; Vallée, M; Barik, J; Tronche, F; Desmedt, A; Piazza, P V

    2010-01-01

    The activation of glucocorticoid receptors (GR) by glucocorticoids increases stress-related memory through the activation of the MAPK signaling pathway and the downstream transcription factor Egr-1. Here, using converging in vitro and in vivo approaches, respectively, GR-expressing cell lines, culture of hippocampal neurons, and GR genetically modified mice (GRNesCre), we identified synapsin-Ia/Ib as one of the effectors of the glucocorticoid signaling cascade. Stress and glucocorticoid-induced activation of the GR modulate synapsin-Ia/Ib through two complementary mechanisms. First, glucocorticoids driving Egr-1 expression increase the expression of synapsin-Ia/Ib, and second, glucocorticoids driving MAPK activation increase its phosphorylation. Finally, we showed that blocking fucosylation of synapsin-Ia/Ib in the hippocampus inhibits its expression and prevents the glucocorticoid-mediated increase in stress-related memory. In conclusion, our data provide a complete molecular pathway (GR/Egr-1/MAPK/Syn-Ia/Ib) through which stress and glucocorticoids enhance the memory of stress-related events and highlight the function of synapsin-Ia/Ib as molecular effector of the behavioral effects of stress. PMID:20368707

  8. Event Congruency Enhances Episodic Memory Encoding through Semantic Elaboration and Relational Binding

    PubMed Central

    Staresina, Bernhard P.; Gray, James C.

    2009-01-01

    Behavioral research consistently shows that congruous events, that is, events whose constituent elements match along some specific dimension, are better remembered than incongruous events. Although it has been speculated that this “congruency subsequent memory effect” (cSME) results from enhanced semantic elaboration, empirical evidence for this account is lacking. Here, we report a set of behavioral and neuroimaging experiments demonstrating that congruous events engage regions along the left inferior frontal gyrus (LIFG)—consistently related to semantic elaboration—to a significantly greater degree than incongruous events, providing evidence in favor of this hypothesis. Critically, we additionally report 3 novel findings in relation to event congruency: First, congruous events yield superior memory not only for a given study item but also for associated source details. Second, the cSME is evident not only for events that matched a semantic context but also for those that matched a subjective aesthetic schema. Finally, functional magnetic resonance imaging brain/behavior correlation analysis reveals a strong link between 1) across-subject variation in the magnitude of the cSME and 2) differential right hippocampal activation, suggesting that episodic memory for congruous events is effectively bolstered by the extent to which semantic associations are generated and relationally integrated via LIFG-hippocampal–encoding mechanisms. PMID:18820289

  9. Relations among acute and chronic nicotine administration, short-term memory, and tactics of data analysis.

    PubMed

    Kangas, Brian D; Branch, Marc N

    2012-09-01

    Emerging evidence suggests that nicotine may enhance short-term memory. Some of this evidence comes from nonhuman primate research using a procedure called delayed matching-to-sample, wherein the monkey is trained to select a comparison stimulus that matches some physical property of a previously presented sample stimulus. Delays between sample stimulus offset and comparison stimuli onset are manipulated and accuracy is measured. The present research attempted to systematically replicate these enhancement effects with pigeons. In addition, the effects of nicotine were assessed under another, more dynamic, memory task called titrating-delay matching-to-sample. In this procedure, the delay between sample offset and comparison onset adjusts as a function of the subject's performance. Correct matches increase the delay, mismatches decrease the delay, and titrated delay values serve as the primary dependent measure. Both studies examined nicotine's effects under acute and chronic administration. Neither provided clear or compelling evidence of memory enhancement following nicotine administration despite reliable and systematic dose-related changes in response latency measures. A modest dose-related effect on accuracy was found, but the magnitude of the effect appears to be directly related to tactics of data analysis involving best-dose analyses of a very circumscribed subset of trial types.

  10. Reactivation of Reward-Related Patterns from Single Past Episodes Supports Memory-Based Decision Making.

    PubMed

    Wimmer, G Elliott; Büchel, Christian

    2016-03-09

    Rewarding experiences exert a strong influence on later decision making. While decades of neuroscience research have shown how reinforcement gradually shapes preferences, decisions are often influenced by single past experiences. Surprisingly, relatively little is known about the influence of single learning episodes. Although recent work has proposed a role for episodes in decision making, it is largely unknown whether and how episodic experiences contribute to value-based decision making and how the values of single episodes are represented in the brain. In multiple behavioral experiments and an fMRI experiment, we tested whether and how rewarding episodes could support later decision making. Participants experienced episodes of high reward or low reward in conjunction with incidental, trial-unique neutral pictures. In a surprise test phase, we found that participants could indeed remember the associated level of reward, as evidenced by accurate source memory for value and preferences to re-engage with rewarded objects. Further, in a separate experiment, we found that high-reward objects shown as primes before a gambling task increased financial risk taking. Neurally, re-exposure to objects in the test phase led to significant reactivation of reward-related patterns. Importantly, individual variability in the strength of reactivation predicted value memory performance. Our results provide a novel demonstration that affect-related neural patterns are reactivated during later experience. Reactivation of value information represents a mechanism by which memory can guide decision making.

  11. fMRI and sleep correlates of the age-related impairment in motor memory consolidation.

    PubMed

    Fogel, Stuart M; Albouy, Genevieve; Vien, Catherine; Popovicci, Romana; King, Bradley R; Hoge, Rick; Jbabdi, Saad; Benali, Habib; Karni, Avi; Maquet, Pierre; Carrier, Julie; Doyon, Julien

    2014-08-01

    Behavioral studies indicate that older adults exhibit normal motor sequence learning (MSL), but paradoxically, show impaired consolidation of the new memory trace. However, the neural and physiological mechanisms underlying this impairment are entirely unknown. Here, we sought to identify, through functional magnetic resonance imaging during MSL and electroencephalographic (EEG) recordings during daytime sleep, the functional correlates and physiological characteristics of this age-related motor memory deficit. As predicted, older subjects did not exhibit sleep-dependent gains in performance (i.e., behavioral changes that reflect consolidation) and had reduced sleep spindles compared with young subjects. Brain imaging analyses also revealed that changes in activity across the retention interval in the putamen and related brain regions were associated with sleep spindles. This change in striatal activity was increased in young subjects, but reduced by comparison in older subjects. These findings suggest that the deficit in sleep-dependent motor memory consolidation in elderly individuals is related to a reduction in sleep spindle oscillations and to an associated decrease of activity in the cortico-striatal network.

  12. Intracranial self-stimulation induces expression of learning and memory-related genes in rat amygdala.

    PubMed

    Kadar, E; Aldavert-Vera, L; Huguet, G; Costa-Miserachs, D; Morgado-Bernal, I; Segura-Torres, P

    2011-02-01

    Intracranial self-stimulation (ICSS) in the lateral hypothalamus improves memory when administered immediately after a training session. In our laboratory, ICSS has been shown as a very reliable way to increase two-way active avoidance (TWAA) conditioning, an amygdala-dependent task. The aim of this work was to study, in the rat amygdala, anatomical and molecular aspects of ICSS, using the same parameters facilitating TWAA. First, we examined the activation of ipsilateral and contralateral lateral (LA) and basolateral (BLA) amygdala, the main amygdalar regions involved in the TWAA, by the immunohistochemical determination of c-Fos protein expression. Second, we tested the effects of the ICSS treatment on the expression of 14 genes related to learning and memory processes using real-time polymerase chain reaction. Results showed a bilateral increase in c-Fos protein expression in LA and BLA nuclei after ICSS treatment. We also found that Fos, brain-derived nerve growth factor (BDNF), Arc, inducible cAMP early repressor (ICER), COX-2, Dnajb1, FKpb5 and Ret genes were upregulated in the amygdala 90 min and 4.5 h post ICSS. From this set of genes, BDNF, Arc and ICER are functionally associated with the cAMP-responsive element-mediated gene transcription molecular pathway that plays a pivotal role in memory, whereas Dnajb1 and Ret are associated with protein folding required for plasticity or neuroprotection. Our results suggest that ICSS induces expression of genes related with synaptic plasticity and protein folding functions in the rat amygdaloid area, which may be involved in the molecular mechanisms by which ICSS may improve or restore memory functions related to this brain structure.

  13. DRYAD and ADH: Further comments on explaining age-related differences in memory.

    PubMed

    Naveh-Benjamin, Moshe; Smyth, Andrea C

    2016-02-01

    Recently, Smyth and Naveh-Benjamin (2016) questioned some of the main assumptions/hypotheses of DRYAD (or density of representations yields age-related deficits), a global-deficit model of aging and memory judgments (Benjamin, 2010; Benjamin et al., 2012). Smyth and Naveh-Benjamin (2016) provided empirical evidence that seems incompatible with DRYAD, but that fits the associative deficit hypothesis (ADH; Naveh-Benjamin, 2000), 1 specific-deficit theoretical view. In response, Aaron Benjamin (2016) offered a discussion of the complementary strengths and weaknesses of the DRYAD and the ADH, and the potential ways they might work together. We agree with many of his comments, but are not convinced that DRYAD is able to explain basic replicable empirical evidence of the type mentioned in Smyth and Naveh-Benjamin (2016). We discuss the reasons why we are not fully convinced by the demonstration of DRYAD's simulation of results presented in Benjamin (2016) and then present an implementation of ADH in a computationally based age-related impaired neuromodulation approach that was shown to simulate the basic empirical results of age-related associative memory deficits. We also discuss the issues of parsimony of theories and the appropriate type of representation, in the context of global versus specific deficits theoretical views. Finally, we show that the ADH's take on the distinction between items and associations has been adopted by some global computational models of memory. We believe that considerations of the above issues and others raised by Benjamin (2016) can lead to fruitful discussions that will benefit both theory development and existing knowledge of aging and memory.

  14. How do verbal short-term memory and working memory relate to the acquisition of vocabulary and grammar? A comparison between first and second language learners.

    PubMed

    Verhagen, Josje; Leseman, Paul

    2016-01-01

    Previous studies show that verbal short-term memory (VSTM) is related to vocabulary learning, whereas verbal working memory (VWM) is related to grammar learning in children learning a second language (L2) in the classroom. In this study, we investigated whether the same relationships apply to children learning an L2 in a naturalistic setting and to monolingual children. We also investigated whether relationships with verbal memory differ depending on the type of grammar skill investigated (i.e., morphology vs. syntax). Participants were 63 Turkish children who learned Dutch as an L2 and 45 Dutch monolingual children (mean age = 5 years). Children completed a series of VSTM and VWM tasks, a Dutch vocabulary task, and a Dutch grammar task. A confirmatory factor analysis showed that VSTM and VWM represented two separate latent factors in both groups. Structural equation modeling showed that VSTM, treated as a latent factor, significantly predicted vocabulary and grammar. VWM, treated as a latent factor, predicted only grammar. Both memory factors were significantly related to the acquisition of morphology and syntax. There were no differences between the two groups. These results show that (a) VSTM and VWM are differentially associated with language learning and (b) the same memory mechanisms are employed for learning vocabulary and grammar in L1 children and in L2 children who learn their L2 naturalistically.

  15. Thinking about the future early in life: the role of relational memory.

    PubMed

    Richmond, Jenny L; Pan, Rose

    2013-04-01

    The constructive episodic simulation hypothesis suggests that we imagine possible future events by flexibly recombining details of past experiences to produce novel scenarios. Here we tested this hypothesis by determining whether episodic future thinking is related to relational memory ability during the preschool years. Children (3- to 5-year-olds) were asked to remember a past event and imagine a possible future event using an adapted version of the recombination paradigm. Relational learning and inference were assessed using a task adapted from the neuroimaging literature. The results show that preschoolers were able to describe both past and possible future events; however, they produced more specific episodic details in relation to past events relative to future events. Episodic future thinking performance was correlated with performance on the relational inference task, consistent with the idea that the ability to flexibly recombine relational knowledge is critical in episodic future thinking.

  16. Cognitive and neuropsychological underpinnings of relational and conjunctive working memory binding across age.

    PubMed

    van Geldorp, Bonnie; Parra, Mario A; Kessels, Roy P C

    2015-01-01

    The ability to form associations (i.e., binding) is critical for memory formation. Recent studies suggest that aging specifically affects relational binding (associating separate features) but not conjunctive binding (integrating features within an object). Possibly, this dissociation may be driven by the spatial nature of the studies so far. Alternatively, relational binding may simply require more attentional resources. We assessed relational and conjunctive binding in three age groups and we included an interfering task (i.e., an articulatory suppression task). Binding was examined in a working memory (WM) task using non-spatial features: shape and colour. Thirty-one young adults (mean age = 22.35), 30 middle-aged adults (mean age = 54.80) and 30 older adults (mean age = 70.27) performed the task. Results show an effect of type of binding and an effect of age but no interaction between type of binding and age. The interaction between type of binding and interference was significant. These results indicate that aging affects relational binding and conjunctive binding similarly. However, relational binding is more susceptible to interference than conjunctive binding, which suggests that relational binding may require more attentional resources. We suggest that a general decline in WM resources associated with frontal dysfunction underlies age-related deficits in WM binding.

  17. Age-related differences on event-related potentials and brain rhythm oscillations during working memory activation.

    PubMed

    Missonnier, Pascal; Herrmann, François R; Rodriguez, Christelle; Deiber, Marie-Pierre; Millet, Phiippe; Fazio-costa, Lara; Gold, Gabriel; Giannakopoulos, Panteleimon

    2011-06-01

    Previous functional imaging studies have pointed to the compensatory recruitment of cortical circuits in old age in order to counterbalance the loss of neural efficiency and preserve cognitive performance. Recent electroencephalographic (EEG) analyses reported age-related deficits in the amplitude of an early positive-negative working memory (PN(wm)) component as well as changes in working memory (WM)-load related brain oscillations during the successful performance of the n-back task. To explore the age-related differences of EEG activation in the face of increasing WM demands, we assessed the PN(wm) component area, parietal alpha event-related synchronization (ERS) as well as frontal theta ERS in 32 young and 32 elderly healthy individuals who successfully performed a highly WM demanding 3-back task. PN(wm) area increased with higher memory loads (3- and 2-back > 0-back tasks) in younger subjects. Older subjects reached the maximal values for this EEG parameter during the less WM demanding 0-back task. They showed a rapid development of an alpha ERS that reached its maximal amplitude at around 800 ms after stimulus onset. In younger subjects, the late alpha ERS occurred between 1,200 and 2,000 ms and its amplitude was significantly higher compared with elders. Frontal theta ERS culmination peak decreased in a task-independent manner in older compared with younger cases. Only in younger individuals, there was a significant decrease in the phasic frontal theta ERS amplitude in the 2- and 3-back tasks compared with the detection and 0-back tasks. These observations suggest that older adults display a rapid mobilization of their neural generators within the parietal cortex to manage very low demanding WM tasks. Moreover, they are less able to activate frontal theta generators during attentional tasks compared with younger persons.

  18. Moringa oleifera mitigates memory impairment and neurodegeneration in animal model of age-related dementia.

    PubMed

    Sutalangka, Chatchada; Wattanathorn, Jintanaporn; Muchimapura, Supaporn; Thukham-mee, Wipawee

    2013-01-01

    To date, the preventive strategy against dementia is still essential due to the rapid growth of its prevalence and the limited therapeutic efficacy. Based on the crucial role of oxidative stress in age-related dementia and the antioxidant and nootropic activities of Moringa oleifera, the enhancement of spatial memory and neuroprotection of M. oleifera leaves extract in animal model of age-related dementia was determined. The possible underlying mechanism was also investigated. Male Wistar rats, weighing 180-220 g, were orally given M. oleifera leaves extract at doses of 100, 200, and 400 mg/kg at a period of 7 days before and 7 days after the intracerebroventricular administration of AF64A bilaterally. Then, they were assessed memory, neuron density, MDA level, and the activities of SOD, CAT, GSH-Px, and AChE in hippocampus. The results showed that the extract improved spatial memory and neurodegeneration in CA1, CA2, CA3, and dentate gyrus of hippocampus together with the decreased MDA level and AChE activity but increased SOD and CAT activities. Therefore, our data suggest that M. oleifera leaves extract is the potential cognitive enhancer and neuroprotectant. The possible mechanism might occur partly via the decreased oxidative stress and the enhanced cholinergic function. However, further explorations concerning active ingredient(s) are still required.

  19. Moringa oleifera Mitigates Memory Impairment and Neurodegeneration in Animal Model of Age-Related Dementia

    PubMed Central

    Sutalangka, Chatchada; Wattanathorn, Jintanaporn; Muchimapura, Supaporn; Thukham-mee, Wipawee

    2013-01-01

    To date, the preventive strategy against dementia is still essential due to the rapid growth of its prevalence and the limited therapeutic efficacy. Based on the crucial role of oxidative stress in age-related dementia and the antioxidant and nootropic activities of Moringa oleifera, the enhancement of spatial memory and neuroprotection of M. oleifera leaves extract in animal model of age-related dementia was determined. The possible underlying mechanism was also investigated. Male Wistar rats, weighing 180–220 g, were orally given M. oleifera leaves extract at doses of 100, 200, and 400 mg/kg at a period of 7 days before and 7 days after the intracerebroventricular administration of AF64A bilaterally. Then, they were assessed memory, neuron density, MDA level, and the activities of SOD, CAT, GSH-Px, and AChE in hippocampus. The results showed that the extract improved spatial memory and neurodegeneration in CA1, CA2, CA3, and dentate gyrus of hippocampus together with the decreased MDA level and AChE activity but increased SOD and CAT activities. Therefore, our data suggest that M. oleifera leaves extract is the potential cognitive enhancer and neuroprotectant. The possible mechanism might occur partly via the decreased oxidative stress and the enhanced cholinergic function. However, further explorations concerning active ingredient(s) are still required. PMID:24454988

  20. Changes in pattern completion – a key mechanism to explain age-related recognition memory deficits?

    PubMed Central

    Vieweg, Paula; Stangl, Matthias; Howard, Lorelei R.; Wolbers, Thomas

    2016-01-01

    Accurate memory retrieval from partial or degraded input requires the reactivation of memory traces, a hippocampal mechanism termed pattern completion. Age-related changes in hippocampal integrity have been hypothesized to shift the balance of memory processes in favor of the retrieval of already stored information (pattern completion), to the detriment of encoding new events (pattern separation). Using a novel behavioral paradigm, we investigated the impact of cognitive aging (1) on recognition performance across different levels of stimulus completeness, and (2) on potential response biases. Participants were required to identify previously learned scenes among new ones. Additionally, all stimuli were presented in gradually masked versions to alter stimulus completeness. Both young and older adults performed increasingly poorly as the scenes became less complete, and this decline in performance was more pronounced in elderly participants indicative of a pattern completion deficit. Intriguingly, when novel scenes were shown, only the older adults showed an increased tendency to identify these as familiar scenes. In line with theoretical models, we argue that this reflects an age-related bias towards pattern completion. PMID:25597525

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

    PubMed

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

    2016-06-01

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

  2. Spatial reconstruction by patients with hippocampal damage is dominated by relational memory errors.

    PubMed

    Watson, Patrick D; Voss, Joel L; Warren, David E; Tranel, Daniel; Cohen, Neal J

    2013-07-01

    Hippocampal damage causes profound yet circumscribed memory impairment across diverse stimulus types and testing formats. Here, within a single test format involving a single class of stimuli, we identified different performance errors to better characterize the specifics of the underlying deficit. The task involved study and reconstruction of object arrays across brief retention intervals. The most striking feature of patients' with hippocampal damage performance was that they tended to reverse the relative positions of item pairs within arrays of any size, effectively "swapping" pairs of objects. These "swap errors" were the primary error type in amnesia, almost never occurred in healthy comparison participants, and actually contributed to poor performance on more traditional metrics (such as distance between studied and reconstructed location). Patients made swap errors even in trials involving only a single pair of objects. The selectivity and severity of this particular deficit creates serious challenges for theories of memory and hippocampus.

  3. Electromagnetic emission memory phenomena related to LiF ionic crystal deformation

    NASA Astrophysics Data System (ADS)

    Mavromatou, C.; Tombras, G. S.; Ninos, D.; Hadjicontis, V.

    2008-04-01

    During the uniaxial compression of LiF ionic monocrystals, acoustic and electromagnetic emissions (EME) are detected. We observed that when the compression is performed in successive loading, unloading cycles and these emissions are being monitored, no new emissions will occur unless the maximum stress of the previous cycle is exceeded, meaning that the material presents memory characteristics. This is observed not only for the acoustic emission (AE), which is the well known Kaiser effect, but for the EME as well. In other words, the material appears to memorize and reveal the previously maximum stress it suffered while being deformed. The importance of an electromagnetic memory feature of a material can be related to various applications in material science, especially when the detection of AE is not feasible or gives false alert. Such cases may very well be earthquakes' predictive indications, monitoring of mines' stability, imminent landslides, etc.

  4. Activities, self-referent memory beliefs, and cognitive performance: evidence for direct and mediated relations.

    PubMed

    Jopp, Daniela; Hertzog, Christopher

    2007-12-01

    In this study, the authors investigated the role of activities and self-referent memory beliefs for cognitive performance in a life-span sample. A factor analysis identified 8 activity factors, including Developmental Activities, Experiential Activities, Social Activities, Physical Activities, Technology Use, Watching Television, Games, and Crafts. A second-order general activity factor was significantly related to a general factor of cognitive function as defined by ability tests. Structural regression models suggested that prediction of cognition by activity level was partially mediated by memory beliefs, controlling for age, education, health, and depressive affect. Models adding paths from general and specific activities to aspects of crystallized intelligence suggested additional unique predictive effects for some activities. In alternative models, nonsignificant effects of beliefs on activities were detected when cognition predicted both variables, consistent with the hypothesis that beliefs derive from monitoring cognition and have no influence on activity patterns.

  5. Age-related differences on a new test of temporal order memory for everyday events.

    PubMed

    Seewald, P Michelle; De Jesus, Shannon Y; Graves, Lisa V; Moreno, Charles C; Mattson, Sarah N; Gilbert, Paul E

    2017-03-07

    We developed a new test to examine incidental temporal order memory for a self-generated sequence of tasks one might complete in everyday life. Young and older adults were given 10 cards, each listing a task one might accomplish in a typical day. Participants were asked to self-generate a "to do" list by placing the 10 cards in a sequence representing the order in which they would accomplish the tasks, but were not informed of a subsequent memory test. We assessed immediate free recall, delayed free recall, and delayed cued recall for the order of the tasks in the sequence. Older adults were significantly impaired relative to young adults on immediate free recall, delayed free recall, and delayed cued recall. Correlation analyses with standardized neuropsychological tests provide preliminary evidence for construct validity for our test, which is portable and can be rapidly administered in clinical or laboratory settings.

  6. Association of metabolic syndrome with sensory gating deficits in patients with chronic schizophrenia.

    PubMed

    Micoulaud-Franchi, Jean-Arthur; Faugere, Mélanie; Boyer, Laurent; Cermolacce, Michel; Richieri, Raphaëlle; Faget, Catherine; Philip, Pierre; Vion-Dury, Jean; Lancon, Christophe

    2015-07-01

    Metabolic syndrome is more prevalent in schizophrenia than in the general population and is associated with an increased rate of morbidity. It has been associated with cognitive impairments in schizophrenia, which are a core deficit in patients with chronic schizophrenia. Sensory gating deficit is also a core deficit in schizophrenia. The principal objective of this study was to investigate the relationship between sensory gating deficit and metabolic syndrome in patients with schizophrenia, after adjusting for key confounding factors. We hypothesized that patients with metabolic syndrome exhibit a higher rate of sensory gating deficit compared to those without metabolic syndrome. This study investigated sensory gating with the auditory event-related potential method by measuring P50 amplitude changes in a double click conditioning-testing procedure in 51 patients with schizophrenia. Patients with metabolic syndrome (n = 14) had a higher rate of sensory gating deficit (P50 suppression <50%) (p < 0.001) compared to those without metabolic syndrome (n = 37). This result remained significant (B = 2.94, Wald = 8.32, p = 0.004) after taking into account 5 potential confounding factors (age, gender, duration of disorder, Fagerström test, presence of clozapine or olanzapine). In patients without metabolic syndrome, sensory gating deficit was linked to a poorer attentional performance (rho = -0.371, p = 0.05). In patients with metabolic syndrome, sensory gating deficit was linked to poorer memory performance (rho = -0.635, p = 0.02). These findings suggest that metabolic syndrome may be linked to sensory gating deficit in patients with schizophrenia and that the relationship between neurocognitive function and sensory gating deficit could be affected by the metabolic status of the patients. Further studies are needed to address the causal relationship between sensory gating deficit related to schizophrenia, cognitive impairments and metabolic syndrome.

  7. Developmental differences in relations between parent-reported executive function and unitized and non-unitized memory representations during childhood

    PubMed Central

    Blankenship, Sarah L.; Riggins, Tracy

    2015-01-01

    Previous research has documented an association between executive functioning (EF) and memory for bound details. However, it is unknown if this relation varies as a function of the type of bound information (i.e., unitized versus non-unitized) and whether this association changes as a function of age during childhood, when both EF and memory undergo rapid development. The current study sought to address these gaps by examining whether relations between parent-reported EF differed for unitized versus non-unitized memory representations and if these relations differed between children who were 4, 6, or 8 years of age. Results revealed that EF was selectively associated with non-unitized associative memory in 8-year-old children; no significant relations between EF and either memory condition were evident in 4- or 6-year-olds. These results suggest relations between EF and memory may be specific to non-unitized representations and that this association may emerge across childhood as both EF and memory abilities develop. PMID:26347683

  8. Relations between Short-term Memory Deficits, Semantic Processing, and Executive Function

    PubMed Central

    Allen, Corinne M.; Martin, Randi C.; Martin, Nadine

    2012-01-01

    Background Previous research has suggested separable short-term memory (STM) buffers for the maintenance of phonological and lexical-semantic information, as some patients with aphasia show better ability to retain semantic than phonological information and others show the reverse. Recently, researchers have proposed that deficits to the maintenance of semantic information in STM are related to executive control abilities. Aims The present study investigated the relationship of executive function abilities with semantic and phonological short-term memory (STM) and semantic processing in such patients, as some previous research has suggested that semantic STM deficits and semantic processing abilities are critically related to specific or general executive function deficits. Method and Procedures 20 patients with aphasia and STM deficits were tested on measures of short-term retention, semantic processing, and both complex and simple executive function tasks. Outcome and Results In correlational analyses, we found no relation between semantic STM and performance on simple or complex executive function tasks. In contrast, phonological STM was related to executive function performance in tasks that had a verbal component, suggesting that performance in some executive function tasks depends on maintaining or rehearsing phonological codes. Although semantic STM was not related to executive function ability, performance on semantic processing tasks was related to executive function, perhaps due to similar executive task requirements in both semantic processing and executive function tasks. Conclusions Implications for treatment and interpretations of executive deficits are discussed. PMID:22736889

  9. Neural mechanisms underlying the reward-related enhancement of motivation when remembering episodic memories with high difficulty.

    PubMed

    Shigemune, Yayoi; Tsukiura, Takashi; Nouchi, Rui; Kambara, Toshimune; Kawashima, Ryuta

    2017-04-04

    The motivation to receive rewards enhances episodic memories, and the motivation is modulated by task difficulty. In episodic retrieval, however, functional neuroimaging evidence regarding the motivation that mediates interactions between reward and task difficulty is scarce. The present fMRI study investigated this issue. During encoding performed without fMRI, participants encoded Japanese words using either deep or shallow strategies, which led to variation in difficulty level during subsequent retrieval. During retrieval with fMRI, participants recognized the target words in either high or low monetary reward conditions. In the behavioral results, a reward-related enhancement of memory was found only when the memory retrieval was difficult, and the rewarding effect on subjective motivation was greater in the retrieval of memories with high difficulty than those with low difficulty. The fMRI data showed that reward-related increases in the activation of the substantia nigra/ventral tegmental area (SN/VTA), medial temporal lobe (MTL), dorsomedial prefrontal cortex (dmPFC), and dorsolateral prefrontal cortex (dlPFC) were greater during the retrieval of memories with high difficulty than those with low difficulty. Furthermore, reward-related enhancement of functional connectivity between the SN/VTA and MTL and between the SN/VTA and dmPFC during the retrieval of memories with high difficulty was significantly correlated with reward-related increases of retrieval accuracy and subjective motivation. The reward-related enhancement of episodic retrieval and retrieval-related motivation could be most effective when the level of retrieval difficulty is optimized. Such reward-related enhancement of memory and motivation could be modulated by a network including the reward-related SN/VTA, motivation-related dmPFC, and memory-related MTL. Hum Brain Mapp, 2017. © 2017 Wiley Periodicals, Inc.

  10. How do working-memory-related demand, reasoning ability and aversive reinforcement modulate conflict monitoring?

    PubMed Central

    Leue, Anja; Weber, Bernd; Beauducel, André

    2014-01-01

    Conflict monitoring is a process of stimulus evaluation and a pre-requisite for subsequent recruitment of cognitive control and behavioral adaptations. This study investigated how experimentally manipulated working-memory-related cognitive demand and aversive reinforcement modulate individual differences of conflict monitoring intensity and behavioral adjustments. Individual differences were assessed by means of an anxiety-related trait dimension (trait-BIS) and by means of reasoning abilities—a core determinant of intelligence. Moreover, we investigated the special role of verbal reasoning ability and figural reasoning ability for the modulation of the conflict monitoring intensity. Ninety participants performed a go/nogo task with four conditions each comprising a combination of low vs. high working-memory-related cognitive demand and low vs. high aversive reinforcement. No effect of aversive reinforcement was observed for the N2 amplitude. The fronto-central nogo N2 amplitude was more pronounced for high demand vs. low demand suggesting that cognitive demand served as an aversive costly event. Higher total reasoning abilities were associated with more intense conflict monitoring and shorter response times with increasing aversive reinforcement (defined as verbal error-feedback vs. monetary loss). Individuals with higher trait-BIS scores demonstrated a more intense conflict monitoring even in conditions with low aversive reinforcement and also a more cautious responding (i.e., response times slowing) with increasing aversive reinforcement indicating a focus on negative feedback prevention. The findings provide evidence for the conflict monitoring theory and suggest that working-memory-related demand overrules the impact of aversive reinforcement on conflict monitoring intensity. Reasoning abilities and anxiety-related traits go along with an intensification of conflict monitoring but differences in the flexibility of behavioral adjustment. PMID:24782739

  11. How do working-memory-related demand, reasoning ability and aversive reinforcement modulate conflict monitoring?

    PubMed

    Leue, Anja; Weber, Bernd; Beauducel, André

    2014-01-01

    Conflict monitoring is a process of stimulus evaluation and a pre-requisite for subsequent recruitment of cognitive control and behavioral adaptations. This study investigated how experimentally manipulated working-memory-related cognitive demand and aversive reinforcement modulate individual differences of conflict monitoring intensity and behavioral adjustments. Individual differences were assessed by means of an anxiety-related trait dimension (trait-BIS) and by means of reasoning abilities-a core determinant of intelligence. Moreover, we investigated the special role of verbal reasoning ability and figural reasoning ability for the modulation of the conflict monitoring intensity. Ninety participants performed a go/nogo task with four conditions each comprising a combination of low vs. high working-memory-related cognitive demand and low vs. high aversive reinforcement. No effect of aversive reinforcement was observed for the N2 amplitude. The fronto-central nogo N2 amplitude was more pronounced for high demand vs. low demand suggesting that cognitive demand served as an aversive costly event. Higher total reasoning abilities were associated with more intense conflict monitoring and shorter response times with increasing aversive reinforcement (defined as verbal error-feedback vs. monetary loss). Individuals with higher trait-BIS scores demonstrated a more intense conflict monitoring even in conditions with low aversive reinforcement and also a more cautious responding (i.e., response times slowing) with increasing aversive reinforcement indicating a focus on negative feedback prevention. The findings provide evidence for the conflict monitoring theory and suggest that working-memory-related demand overrules the impact of aversive reinforcement on conflict monitoring intensity. Reasoning abilities and anxiety-related traits go along with an intensification of conflict monitoring but differences in the flexibility of behavioral adjustment.

  12. Design of bull’s eye structures on gate-defined lateral quantum dots

    NASA Astrophysics Data System (ADS)

    Fukai, Rio; Nakagawa, Tomohiro; Kiyama, Haruki; Oiwa, Akira

    2017-04-01

    Quantum repeaters are required for realizing long-distance quantum communication. The quantum repeater consists of a quantum memory to store quantum information and an interface between photonic flying qubits and the memory qubits. Electron spins in gate-defined quantum dots (QDs), which have a relatively long coherence time and high electrical tunability, are promising candidates for such memory qubits because the fundamental technologies of detecting and manipulating single photoelectron spins have been established. The remaining challenge for the realization of quantum repeaters is an efficient coupling between photons and electron spins in the QDs. In this study, we discuss the enhancement of the transmission and the maintenance of the incident light polarization through bull’s eye structures on gate-defined QDs on the basis of electromagnetic field simulations.

  13. Application of Item Response Theory to Tests of Substance-related Associative Memory

    PubMed Central

    Shono, Yusuke; Grenard, Jerry L.; Ames, Susan L.; Stacy, Alan W.

    2015-01-01

    A substance-related word association test (WAT) is one of the commonly used indirect tests of substance-related implicit associative memory and has been shown to predict substance use. This study applied an item response theory (IRT) modeling approach to evaluate psychometric properties of the alcohol- and marijuana-related WATs and their items among 775 ethnically diverse at-risk adolescents. After examining the IRT assumptions, item fit, and differential item functioning (DIF) across gender and age groups, the original 18 WAT items were reduced to 14- and 15-items in the alcohol- and marijuana-related WAT, respectively. Thereafter, unidimensional one- and two-parameter logistic models (1PL and 2PL models) were fitted to the revised WAT items. The results demonstrated that both alcohol- and marijuana-related WATs have good psychometric properties. These results were discussed in light of the framework of a unified concept of construct validity (Messick, 1975, 1989, 1995). PMID:25134051

  14. False memory and level of processing effect: an event-related potential study.

    PubMed

    Beato, Maria Soledad; Boldini, Angela; Cadavid, Sara

    2012-09-12

    Event-related potentials (ERPs) were used to determine the effects of level of processing on true and false memory, using the Deese-Roediger-McDermott (DRM) paradigm. In the DRM paradigm, lists of words highly associated to a single nonpresented word (the 'critical lure') are studied and, in a subsequent memory test, critical lures are often falsely remembered. Lists with three critical lures per list were auditorily presented here to participants who studied them with either a shallow (saying whether the word contained the letter 'o') or a deep (creating a mental image of the word) processing task. Visual presentation modality was used on a final recognition test. True recognition of studied words was significantly higher after deep encoding, whereas false recognition of nonpresented critical lures was similar in both experimental groups. At the ERP level, true and false recognition showed similar patterns: no FN400 effect was found, whereas comparable left parietal and late right frontal old/new effects were found for true and false recognition in both experimental conditions. Items studied under shallow encoding conditions elicited more positive ERP than items studied under deep encoding conditions at a 1000-1500 ms interval. These ERP results suggest that true and false recognition share some common underlying processes. Differential effects of level of processing on true and false memory were found only at the behavioral level but not at the ERP level.

  15. Evidence for two distinct sleep-related long-term memory consolidation processes.

    PubMed

    Schönauer, Monika; Grätsch, Melanie; Gais, Steffen

    2015-02-01

    Numerous studies examine the effect of a night's sleep on memory consolidation, but few go beyond this short time-scale to test long-lasting effects of sleep on memory. We investigated long-term effects of sleep on typical memory tasks. During the hours following learning, participants slept or stayed awake. We compared recall performance between wake and sleep conditions after delays of up to 6 days. Performance develops in two distinct ways. Word pair, syllable, and motor sequence learning tasks benefit from sleep during the first day after encoding, when compared with daytime or nighttime wakefulness. However, performance in the wake conditions recovers after another night of sleep, so that we observe no lasting effect of sleep. Sleep deprivation before recall does not impair performance. Thus, fatigue cannot adequately explain the lack of long-term effects. We suggest that the hippocampus might serve as a buffer during the retention interval, and consolidation occurs during delayed sleep. In contrast, a non-hippocampal mirror-tracing task benefits significantly from sleep, even when tested after a 4-day delay including recovery sleep. This indicates a dissociation between two sleep-related consolidation mechanisms, which could rely on distinct neuronal processes.

  16. Feature integration in visual working memory: parietal gamma activity is related to cognitive coordination

    PubMed Central

    Muthukumaraswamy, Suresh D.; Hibbs, Carina S.; Shapiro, Kimron L.; Bracewell, R. Martyn; Singh, Krish D.; Linden, David E. J.

    2011-01-01

    The mechanism by which distinct subprocesses in the brain are coordinated is a central conundrum of systems neuroscience. The parietal lobe is thought to play a key role in visual feature integration, and oscillatory activity in the gamma frequency range has been associated with perception of coherent objects and other tasks requiring neural coordination. Here, we examined the neural correlates of integrating mental representations in working memory and hypothesized that parietal gamma activity would be related to the success of cognitive coordination. Working memory is a classic example of a cognitive operation that requires the coordinated processing of different types of information and the contribution of multiple cognitive domains. Using magnetoencephalography (MEG), we report parietal activity in the high gamma (80–100 Hz) range during manipulation of visual and spatial information (colors and angles) in working memory. This parietal gamma activity was significantly higher during manipulation of visual-spatial conjunctions compared with single features. Furthermore, gamma activity correlated with successful performance during the conjunction task but not during the component tasks. Cortical gamma activity in parietal cortex may therefore play a role in cognitive coordination. PMID:21940605

  17. Feature integration in visual working memory: parietal gamma activity is related to cognitive coordination.

    PubMed

    Morgan, Helen M; Muthukumaraswamy, Suresh D; Hibbs, Carina S; Shapiro, Kimron L; Bracewell, R Martyn; Singh, Krish D; Linden, David E J

    2011-12-01

    The mechanism by which distinct subprocesses in the brain are coordinated is a central conundrum of systems neuroscience. The parietal lobe is thought to play a key role in visual feature integration, and oscillatory activity in the gamma frequency range has been associated with perception of coherent objects and other tasks requiring neural coordination. Here, we examined the neural correlates of integrating mental representations in working memory and hypothesized that parietal gamma activity would be related to the success of cognitive coordination. Working memory is a classic example of a cognitive operation that requires the coordinated processing of different types of information and the contribution of multiple cognitive domains. Using magnetoencephalography (MEG), we report parietal activity in the high gamma (80-100 Hz) range during manipulation of visual and spatial information (colors and angles) in working memory. This parietal gamma activity was significantly higher during manipulation of visual-spatial conjunctions compared with single features. Furthermore, gamma activity correlated with successful performance during the conjunction task but not during the component tasks. Cortical gamma activity in parietal cortex may therefore play a role in cognitive coordination.

  18. Music mnemonics aid Verbal Memory and Induce Learning - Related Brain Plasticity in Multiple Sclerosis.

    PubMed

    Thaut, Michael H; Peterson, David A; McIntosh, Gerald C; Hoemberg, Volker

    2014-01-01

    Recent research on music and brain function has suggested that the temporal pattern structure in music and rhythm can enhance cognitive functions. To further elucidate this question specifically for memory, we investigated if a musical template can enhance verbal learning in patients with multiple sclerosis (MS) and if music-assisted learning will also influence short-term, system-level brain plasticity. We measured systems-level brain activity with oscillatory network synchronization during music-assisted learning. Specifically, we measured the spectral power of 128-channel electroencephalogram (EEG) in alpha and beta frequency bands in 54 patients with MS. The study sample was randomly divided into two groups, either hearing a spoken or a musical (sung) presentation of Rey's auditory verbal learning test. We defined the "learning-related synchronization" (LRS) as the percent change in EEG spectral power from the first time the word was presented to the average of the subsequent word encoding trials. LRS differed significantly between the music and the spoken conditions in low alpha and upper beta bands. Patients in the music condition showed overall better word memory and better word order memory and stronger bilateral frontal alpha LRS than patients in the spoken condition. The evidence suggests that a musical mnemonic recruits stronger oscillatory network synchronization in prefrontal areas in MS patients during word learning. It is suggested that the temporal structure implicit in musical stimuli enhances "deep encoding" during verbal learning and sharpens the timing of neural dynamics in brain networks degraded by demyelination in MS.

  19. The Memory That's Right and the Memory That's Left: Event-Related Potentials Reveal Hemispheric Asymmetries in the Encoding and Retention of Verbal Information

    ERIC Educational Resources Information Center

    Evans, Karen M.; Federmeier, Kara D.

    2007-01-01

    We examined the nature and timecourse of hemispheric asymmetries in verbal memory by recording event-related potentials (ERPs) in a continuous recognition task. Participants made overt recognition judgments to test words presented in central vision that were either novel (new words) or had been previously presented in the left or right visual…

  20. Relation between Olfactory Dysfunction and Episodic Verbal Memory in Early Parkinson’s Disease

    PubMed Central

    HANOĞLU, Lütfü; HAKYEMEZ, Hüsniye Aylin; ÖZER, Feriha; ÖZBEN, Serkan; DEMİRCİ, Sema; OĞUZ AKARSU, Emel

    2014-01-01

    Introduction Olfactory dysfunction is an early and common symptom in idiopathic Parkinson’s disease (IPD). Recently, the relation between olfactory dysfunction and cognitive loss in IPD has been reported. In our study, we aimed to investigate the relation between olfactory dysfunction and cognitive impairments in early IPD related with this theory. Methods In this study, we included 28 patients with stage 1 and stage 2 IPD according to the Hoehn-Yahr (H-Y) scale and 19 healthy participants. The University of Pennsylvania Smell Identification Test (UPSIT) was performed for evaluating olfactory function. For cognitive investigation in participants, the clock drawing test, Stroop test, verbal fluency test, Benton face recognition test (BFR), Benton line judgment orientation test (BLO), and Auditory Verbal Learning Test (AVLT) were performed. Results We found significantly lower UPSIT scores in the patient group compared to controls (p=.018). In the neuropsychological investigation, only Stroop test and BLOT test scores were significantly lower in the patient group compared to controls (p=.003, p=.002, respectively). We found a negative correlation between UPSIT scores and Stroop time (p=.033) and Stroop error (p=.037) and a positive correlation between UPSIT scores and SBST long-term memory scores (p=.016) in patients. Conclusion In our study, we found mild cognitive impairment related with visuospatial and executive functions in early-stage IPD compared to controls. But, in the patient group, we detected a different impairment pattern of memory and frontal functions that correlated with hyposmia. This different pattern might be indicating a subgroup of IPD characterized by low performance in episodic verbal memory, with accompanying olfactory dysfunction in the early stage.

  1. Is what goes in what comes out? Encoding and retrieval event-related potentials together determine memory outcome.

    PubMed

    Chen, Yvonne Y; Lithgow, Kirstie; Hemmerich, Jumjury A; Caplan, Jeremy B

    2014-10-01

    Understanding memory function amounts to identifying how events (cognitive and neural) at study eventually influence events at test. Many of the proposed cognitive correlates of memory-related event-related potentials (ERPs) at study resemble proposed cognitive correlates of other memory-related ERPs, recorded at test. We wondered whether a given known ERP feature at study might in fact reflect an effective-encoding process that is, in turn, tapped by another specific ERP feature, recorded at test. To this end, we asked which pairs of known memory-related ERP features explain common variance across a large sample of participants, while they perform a word-recognition task. Two early ERP features, the Late Positive Component (study) and the FN400 (test), covaried significantly. These features also correlated with memory success (d' and response time). Two later ERP features, the Slow Wave (study) and the Late Parietal Positivity (test), also covaried when lures were incorporated into the analysis. Interestingly, these later features were uncorrelated with memory outcome. This novel approach, exploiting naturally occurring subject variability (in strategy and ERP amplitudes), informs our understanding of the memory functions of ERP features in several ways. Specifically, they strengthen the argument that the earlier ERP features may drive old/new recognition (but perhaps not the later features). Our findings suggest the Late Positive Component at study, in some degree, may cause the FN400 to increase at test, together producing effective recognition memory. The Slow Wave at study appears to relate the Left Parietal Positivity at test, but these may play roles in more complex memory judgments and may be less critical for simple old/new recognition.

  2. Sleep Deprivation Accelerates Delay-Related Loss of Visual Short-Term Memories Without Affecting Precision

    PubMed Central

    Wee, Natalie; Asplund, Christopher L.; Chee, Michael W. L.

    2013-01-01

    Study Objectives: Visual short-term memory (VSTM) is an important measure of information processing capacity and supports many higher-order cognitive processes. We examined how sleep deprivation (SD) and maintenance duration interact to influence the number and precision of items in VSTM using an experimental design that limits the contribution of lapses at encoding. Design: For each trial, participants attempted to maintain the location and color of three stimuli over a delay. After a retention interval of either 1 or 10 seconds, participants reported the color of the item at the cued location by selecting it on a color wheel. The probability of reporting the probed item, the precision of report, and the probability of reporting a nonprobed item were determined using a mixture-modeling analysis. Participants were studied twice in counterbalanced order, once after a night of normal sleep and once following a night of sleep deprivation. Setting: Sleep laboratory. Participants: Nineteen healthy college age volunteers (seven females) with regular sleep patterns. Interventions: Approximately 24 hours of total SD. Measurements and Results: SD selectively reduced the number of integrated representations that can be retrieved after a delay, while leaving the precision of object information in the stored representations intact. Delay interacted with SD to lower the rate of successful recall. Conclusions: Visual short-term memory is compromised during sleep deprivation, an effect compounded by delay. However, when memories are retrieved, they tend to be intact. Citation: Wee N; Asplund CL; Chee MWL. Sleep deprivation accelerates delay-related loss of visual short-term memories without affecting precision. SLEEP 2013;36(6):849-856. PMID:23729928

  3. Transistor memory devices with large memory windows, using multi-stacking of densely packed, hydrophobic charge trapping metal nanoparticle array

    NASA Astrophysics Data System (ADS)

    Cho, Ikjun; Kim, Beom Joon; Ryu, Sook Won; Cho, Jeong Ho; Cho, Jinhan

    2014-12-01

    Organic field-effect transistor (OFET) memories have rapidly evolved from low-cost and flexible electronics with relatively low-memory capacities to memory devices that require high-capacity memory such as smart memory cards or solid-state hard drives. Here, we report the high-capacity OFET memories based on the multilayer stacking of densely packed hydrophobic metal NP layers in place of the traditional transistor memory systems based on a single charge trapping layer. We demonstrated that the memory performances of devices could be significantly enhanced by controlling the adsorption isotherm behavior, multilayer stacking structure and hydrophobicity of the metal NPs. For this study, tetraoctylammonium (TOA)-stabilized Au nanoparticles (TOA-AuNPs) were consecutively layer-by-layer (LbL) assembled with an amine-functionalized poly(amidoamine) dendrimer (PAD). The formed (PAD/TOA-AuNP)n films were used as a multilayer stacked charge trapping layer at the interface between the tunneling dielectric layer and the SiO2 gate dielectric layer. For a single AuNP layer (i.e. PAD/TOA-AuNP)1) with a number density of 1.82 × 1012 cm-2, the memory window of the OFET memory device was measured to be approximately 97 V. The multilayer stacked OFET memory devices prepared with four AuNP layers exhibited excellent programmable memory properties (i.e. a large memory window (ΔVth) exceeding 145 V, a fast switching speed (1 μs), a high program/erase (P/E) current ratio (greater than 106) and good electrical reliability) during writing and erasing over a relatively short time scale under an operation voltage of 100 V applied at the gate.

  4. Transistor memory devices with large memory windows, using multi-stacking of densely packed, hydrophobic charge trapping metal nanoparticle array.

    PubMed

    Cho, Ikjun; Kim, Beom Joon; Ryu, Sook Won; Cho, Jeong Ho; Cho, Jinhan

    2014-12-19

    Organic field-effect transistor (OFET) memories have rapidly evolved from low-cost and flexible electronics with relatively low-memory capacities to memory devices that require high-capacity memory such as smart memory cards or solid-state hard drives. Here, we report the high-capacity OFET memories based on the multilayer stacking of densely packed hydrophobic metal NP layers in place of the traditional transistor memory systems based on a single charge trapping layer. We demonstrated that the memory performances of devices could be significantly enhanced by controlling the adsorption isotherm behavior, multilayer stacking structure and hydrophobicity of the metal NPs. For this study, tetraoctylammonium (TOA)-stabilized Au nanoparticles (TOA-Au(NPs)) were consecutively layer-by-layer (LbL) assembled with an amine-functionalized poly(amidoamine) dendrimer (PAD). The formed (PAD/TOA-Au(NP))(n) films were used as a multilayer stacked charge trapping layer at the interface between the tunneling dielectric layer and the SiO2 gate dielectric layer. For a single AuNP layer (i.e. PAD/TOA-Au(NP))1) with a number density of 1.82 × 10(12) cm(-2), the memory window of the OFET memory device was measured to be approximately 97 V. The multilayer stacked OFET memory devices prepared with four Au(NP) layers exhibited excellent programmable memory properties (i.e. a large memory window (ΔV(th)) exceeding 145 V, a fast switching speed (1 μs), a high program/erase (P/E) current ratio (greater than 10(6)) and good electrical reliability) during writing and erasing over a relatively short time scale under an operation voltage of 100 V applied at the gate.

  5. MHC Class I Immune Proteins Are Critical for Hippocampus-Dependent Memory and Gate NMDAR-Dependent Hippocampal Long-Term Depression

    ERIC Educational Resources Information Center

    Nelson, P. Austin; Sage, Jennifer R.; Wood, Suzanne C.; Davenport, Christopher M.; Anagnostaras, Stephan G.; Boulanger, Lisa M.

    2013-01-01

    Memory impairment is a common feature of conditions that involve changes in inflammatory signaling in the brain, including traumatic brain injury, infection, neurodegenerative disorders, and normal aging. However, the causal importance of inflammatory mediators in cognitive impairments in these conditions remains unclear. Here we show that…

  6. Age-Related Frontal Hyperactivation Observed across Different Working Memory Tasks: An fMRI Study

    PubMed Central

    Fakhri, Mohammad; Sikaroodi, Hajir; Maleki, Farid; Ali Oghabian, Mohammad; Ghanaati, Hosein

    2012-01-01

    Purpose: To evaluate patterns of activation, convergence and divergence of three functional magnetic resonance imaging (fMRI) Working Memory (WM) tasks in two different age groups. We want to understand potential impact of task and subjects’ age on WM activations as well as most important areas with regard to WM functions. Materials and methods: Thirty-five healthy volunteers completed visual, verbal, and novel auditory WM tasks. The subjects were selected from age extremes to depict possible impact of normal aging. The General Linear Model was used to report significant activations and the effect of age group. Contrasts revealed differences in activation between tasks, and Combined Task Analysis was performed to determine common regions of activation across tasks. Results: Most of the observed differences between the tasks were seen in areas that were responsible for feature processing. Frontal regions were mainstay activation areas, regardless of the utilized stimulus. We found an age-related reduction in activity of visual (in visually-presented tasks) and auditory (in auditory task) cortices but an age-related increase in prefrontal cortex for all tasks. Conclusion: Regardless of the type of the task stimuli, frontal regions are the most important activation areas in WM processing. These areas are also main targets of age-related changes with regard to activation patterns. Our results also indicate that prefrontal overactivity in working memory might be a compensatory effort to mask age-related decline in sensory processing. PMID:22885811

  7. Illusions and Delusions: Relating Experimentally-Induced False Memories to Anomalous Experiences and Ideas

    PubMed Central

    Corlett, Philip R.; Simons, Jon S.; Pigott, Jennifer S.; Gardner, Jennifer M.; Murray, Graham K.; Krystal, John H.; Fletcher, Paul C.

    2009-01-01

    The salience hypothesis of psychosis rests on a simple but profound observation that subtle alterations in the way that we perceive and experience stimuli have important consequences for how important these stimuli become for us, how much they draw our attention, how they embed themselves in our memory and, ultimately, how they shape our beliefs. We put forward the idea that a classical memory illusion – the Deese–Roediger–McDermott (DRM) effect – offers a useful way of exploring processes related to such aberrant belief formation. The illusion occurs when, as a consequence of its relationship to previous stimuli, a stimulus that has not previously been presented is falsely remembered. Such illusory familiarity is thought to be generated by the surprising fluency with which the stimulus is processed. In this respect, the illusion relates directly to the salience hypothesis and may share common cognitive underpinnings with aberrations of perception and attribution that are found in psychosis. In this paper, we explore the theoretical importance of this experimentally-induced illusion in relation to the salience model of psychosis. We present data showing that, in healthy volunteers, the illusion relates directly to self reported anomalies of experience and magical thinking. We discuss this finding in terms of the salience hypothesis and of a broader Bayesian framework of perception and cognition which emphasizes the salience both of predictable and unpredictable experiences. PMID:19956402

  8. Grapheme-color synesthesia can enhance immediate memory without disrupting the encoding of relational cues.

    PubMed

    Gibson, Bradley S; Radvansky, Gabriel A; Johnson, Ann C; McNerney, M Windy

    2012-12-01

    Previous evidence has suggested that grapheme-color synesthesia can enhance memory for words, but little is known about how these photisms cue retrieval. Often, the encoding of specific features of individual words can disrupt the encoding of ordered relations between words, resulting in an overall decrease in recall accuracy. Here we show that the photisms arising from grapheme-color synesthesia do not function like these item-specific cues. The influences of high and low word frequency on the encoding of ordered relations and the accuracy of immediate free recall were compared across a group of 10 synesthetes and 48 nonsynesthetes. The main findings of Experiment 1 showed that the experience of synesthesia had no adverse effect on the encoding of ordered relations (as measured by input-output correspondence); furthermore, it enhanced recall accuracy in a strictly additive fashion across the two word frequency conditions. Experiment 2 corroborated these findings by showing that the synesthetes only outperformed the nonsynesthetes when the materials involved words and letters, not when they involved digits and spatial locations. Altogether, the present findings suggest that synesthesia can boost immediate memory performance without disrupting the encoding of ordered relations.

  9. Relations between prospective memory, cognitive abilities, and brain structure in adolescents who vary in prenatal drug exposure

    PubMed Central

    Robey, Alison; Buckingham-Howes, Stacy; Salmeron, Betty Jo; Black, Maureen M.; Riggins, Tracy

    2014-01-01

    This investigation examined how prospective memory (PM) relates to cognitive abilities (i.e., executive function, attention, working memory, and retrospective memory), and brain structure in adolescents who vary in prenatal drug exposure (PDE). The sample included 105 (55 female, 50 male) urban, primarily African American adolescents (mean age 15.5 years) from low socioeconomic status (SES) families; 56% (n=59) were prenatally exposed to drugs (heroin and/or cocaine) and 44% (n=46) were not prenatally exposed, but similar in age, gender, race, and SES. Executive functioning, attentional control, working memory, retrospective memory, and overall cognitive ability were assessed by validated performance measures. Executive functioning was also measured by caregiver report. A subset of 52 adolescents completed MRI scans, which provided measures of subcortical gray matter volumes and thickness of prefrontal, parietal and temporal cortices. Results revealed no differences in PM performance by PDE status, even after adjusting for age and IQ. Executive function, retrospective memory, cortical thickness in frontal and parietal regions, and volume of subcortical regions (i.e., putamen and hippocampus) were related to PM performance in the sample overall, even after adjusting for age, IQ, and total gray matter volume. Findings suggest that variations in PM ability during adolescence are robustly related to individual differences in cognitive abilities, in particular executive function and retrospective memory, and brain structure, but do not vary by PDE status. PMID:24630759

  10. APETx1 from sea anemone Anthopleura elegantissima is a gating modifier peptide toxin of the human ether-a-go-go- related potassium channel.

    PubMed

    Zhang, M; Liu, X-S; Diochot, S; Lazdunski, M; Tseng, G-N

    2007-08-01

    We studied the mechanism of action and the binding site of APETx1, a peptide toxin purified from sea anemone, on the human ether-a-go-go-related gene (hERG) channel. Similar to the effects of gating modifier toxins (hanatoxin and SGTx) on the voltage-gated potassium (Kv) 2.1 channel, APETx1 shifts the voltage-dependence of hERG activation in the positive direction and suppresses its current amplitudes elicited by strong depolarizing pulses that maximally activate the channels. The APETx1 binding site is distinctly different from that of a pore-blocking peptide toxin, BeKm-1. Mutations in the S3b region of hERG have dramatic impact on the responsiveness to APETx1: G514C potentiates whereas E518C abolishes the APETx1 effect. Restoring the negative charge at position 518 (methanethiosulfonate ethylsulfonate modification of 518C) partially restores APETx1 responsiveness, supporting an electrostatic interaction between E518 and APETx1. Among the three hERG isoforms, hERG1 and hERG3 are equally responsive to APETx1, whereas hERG2 is insensitive. The key feature seems to be an arginine residue uniquely present at the 514-equivalent position in hERG2, where the other two isoforms possess a glycine. Our data show that APETx1 is a gating modifier toxin of the hERG channel, and its binding site shares characteristics with those of gating modifier toxin binding sites on other Kv channels.

  11. The Incidental Influence of Memories of Past Eating Occasions on Consumers’ Emotional Responses to Food and Food-Related Behaviors

    PubMed Central

    Piqueras-Fiszman, Betina; Jaeger, Sara R.

    2016-01-01

    Our memories of past eating experiences are influential in shaping food preferences and consumption behavior, and the emotions that people associate to these memories are linked to their attitudes toward foods and their everyday food-related behaviors. This work studies the impact that food-related memories have on peoples’ emotional state and how this state is projected in a subsequent evaluation of images pertaining to food and food-related behaviors. Focus is placed on guilt and shame emotions. Through an online survey, three memories were investigated (a positive meal, a routine evening meal, and an overeating occasion) among UK consumers (N = 710). Participants primed with the overeating memory evaluated images related to junk food as conveying more feelings of guilt and shame than did participants primed with the memory of a positive meal. Moreover, this effect was moderated by participants’ dietary restraint status. Participants classified as having a high dietary restraint had stronger associations with the emotions guilt and shame than participants classified as low in dietary restraint. In contrast, a memory of a positive meal did not lead to positive valuations of any of the food-related images shown. Overall, the findings from the present study illustrate the partial impact that personal food memories have on consumers’ emotional response toward food-related issues, which in turn has the potential to affect future behavior. This study therefore contributes to the literature about cognitive effects on food attitudes and behavior. Furthermore, the results suggest that the empirical approach may be tapping into possibly unconscious emotions toward foods and food-related behavior. PMID:27445911

  12. Evaluating the developmental trajectory of the episodic buffer component of working memory and its relation to word recognition in children.

    PubMed

    Wang, Shinmin; Allen, Richard J; Lee, Jun Ren; Hsieh, Chia-En

    2015-05-01

    The creation of temporary bound representation of information from different sources is one of the key abilities attributed to the episodic buffer component of working memory. Whereas the role of working memory in word learning has received substantial attention, very little is known about the link between the development of word recognition skills and the ability to bind information in the episodic buffer of working memory and how it may develop with age. This study examined the performance of Grade 2 children (8 years old), Grade 3 children (9 years old), and young adults on a task designed to measure their ability to bind visual and auditory-verbal information in working memory. Children's performance on this task significantly correlated with their word recognition skills even when chronological age, memory for individual elements, and other possible reading-related factors were taken into account. In addition, clear developmental trajectories were observed, with improvements in the ability to hold temporary bound information in working memory between Grades 2 and 3, and between the child and adult groups, that were independent from memory for the individual elements. These findings suggest that the capacity to temporarily bind novel auditory-verbal information to visual form in working memory is linked to the development of word recognition in children and improves with age.

  13. Adiabatic gate teleportation.

    PubMed

    Bacon, Dave; Flammia, Steven T

    2009-09-18

    The difficulty in producing precisely timed and controlled quantum gates is a significant source of error in many physical implementations of quantum computers. Here we introduce a simple universal primitive, adiabatic gate teleportation, which is robust to timing errors and many control errors and maintains a constant energy gap throughout the computation above a degenerate ground state space. This construction allows for geometric robustness based upon the control of two independent qubit interactions. Further, our piecewise adiabatic evolution easily relates to the quantum circuit model, enabling the use of standard methods from fault-tolerance theory for establishing thresholds.

  14. A Customized Attention-Based Long Short-Term Memory Network for Distant Supervised Relation Extraction.

    PubMed

    He, Dengchao; Zhang, Hongjun; Hao, Wenning; Zhang, Rui; Cheng, Kai

    2017-04-14

    Distant supervision, a widely applied approach in the field of relation extraction can automatically generate large amounts of labeled training corpus with minimal manual effort. However, the labeled training corpus may have many false-positive data, which would hurt the performance of relation extraction. Moreover, in traditional feature-based distant supervised approaches, extraction models adopt human design features with natural language processing. It may also cause poor performance. To address these two shortcomings, we propose a customized attention-based long short-term memory network. Our approach adopts word-level attention to achieve better data representation for relation extraction without manually designed features to perform distant supervision instead of fully supervised relation extraction, and it utilizes instance-level attention to tackle the problem of false-positive data. Experimental results demonstrate that our proposed approach is effective and achieves better performance than traditional methods.

  15. Cognitive interference and a food-related memory bias in binge eating disorder.

    PubMed

    Svaldi, Jennifer; Schmitz, Florian; Trentowska, Monika; Tuschen-Caffier, Brunna; Berking, Matthias; Naumann, Eva

    2014-01-01

    The present study was concerned with cognitive interference and a specific memory bias for eating-related stimuli in binge eating disorder (BED). Further objectives were to find out under which circumstances such effects would occur, and whether they are related with each other and with reported severity of BED symptoms. A group of women diagnosed with BED and a matched sample of overweight controls completed two paradigms, an n-back task with lures and a recent-probes task. The BED group generally experienced more interference in the n-back task. Additionally, they revealed selectively increased interference for food items in the recent-probes task. Findings can be reconciled with the view that control functions are generally impaired in BED, and that there is an additional bias for eating-related stimuli, both of which were related with reported severity of BED symptoms.

  16. Reverse Shape Memory Effect Related to α → γ Transformation in a Fe-Mn-Al-Ni Shape Memory Alloy

    NASA Astrophysics Data System (ADS)

    Peng, Huabei; Huang, Pan; Zhou, Tiannan; Wang, Shanling; Wen, Yuhua

    2017-02-01

    In this study, we investigated the shape memory behavior and phase transformations of solution-treated Fe43.61Mn34.74Al13.38Ni8.27 alloy between room temperature and 1173 K (900 °C). This alloy exhibits the reverse shape memory effect resulting from the phase transformation of α (bcc) → γ (fcc) between 673 K and 1073 K (400 °C and 800 °C) in addition to the shape memory effect resulting from the martensitic reverse transformation of γ' (fcc) → α (bcc) below 673 K (400 °C). There is a high density of hairpin-shaped dislocations in the α phase undergoing the martensitic reverse transformation of γ' → α. The lath γ phase, which preferentially nucleates and grows in the reversed α phase, has the same crystal orientation with the reverse-transformed γ' martensite. However, the vermiculate γ phase, which is precipitated in the α phase between lath γ phase, has different crystal orientations. The lath γ phase is beneficial to attaining better reverse shape memory effect than the vermiculate γ phase.

  17. Memory Effects of Speech and Gesture Binding: Cortical and Hippocampal Activation in Relation to Subsequent Memory Performance

    ERIC Educational Resources Information Center

    Straube, Benjamin; Green, Antonia; Weis, Susanne; Chatterjee, Anjan; Tilo, Kircher

    2009-01-01

    In human face-to-face communication, the content of speech is often illustrated by coverbal gestures. Behavioral evidence suggests that gestures provide advantages in the comprehension and memory of speech. Yet, how the human brain integrates abstract auditory and visual information into a common representation is not known. Our study investigates…

  18. Childhood abuse is related to working memory impairment for positive emotion in female university students.

    PubMed

    Cromheeke, Sofie; Herpoel, Laure-Anne; Mueller, Sven C

    2014-02-01

    Childhood abuse is an important risk factor for depression, anxiety disorders, and substance use later in life. One possible mechanism underlying this association could be deficits in cognitive processing of emotional information. This study tested the impact of distracting emotional information on working memory performance in 21 young women with a history of sexual and physical abuse during childhood/adolescence (mean age = 20.0), and compared their performance to 17 individuals reporting nonabuse-related childhood stress (mean age = 19.6) and a control group of 17 women without a history of childhood stress (mean age = 20.0). During the most difficult distractor condition, working memory accuracy for positive versus neutral incidental emotional stimuli was reduced in women reporting a history of abuse relative to both control groups (with and without nonabuse-related childhood stress). The current results reveal aberrant responses to positive stimuli and are consistent with the notion of persistent influence of childhood abuse on processes critical for emotional well-being and emotion control.

  19. Interactions between mood and the structure of semantic memory: event-related potentials evidence

    PubMed Central

    Pinheiro, Ana P.; del Re, Elisabetta; Nestor, Paul G; McCarley, Robert W.; Gonçalves, Óscar F.

    2013-01-01

    Recent evidence suggests that affect acts as modulator of cognitive processes and in particular that induced mood has an effect on the way semantic memory is used on-line. We used event-related potentials (ERPs) to examine affective modulation of semantic information processing under three different moods: neutral, positive and negative. Fifteen subjects read 324 pairs of sentences, after mood induction procedure with 30 pictures of neutral, 30 pictures of positive and 30 pictures of neutral valence: 108 sentences were read in each mood induction condition. Sentences ended with three word types: expected words, within-category violations, and between-category violations. N400 amplitude was measured to the three word types under each mood induction condition. Under neutral mood, a congruency (more negative N400 amplitude for unexpected relative to expected endings) and a category effect (more negative N400 amplitude for between- than to within-category violations) were observed. Also, results showed differences in N400 amplitude for both within- and between-category violations as a function of mood: while positive mood tended to facilitate the integration of unexpected but related items, negative mood made their integration as difficult as unexpected and unrelated items. These findings suggest the differential impact of mood on access to long-term semantic memory during sentence comprehension. PMID:22434931

  20. Disruption of caudate working memory activation in chronic blast-related traumatic brain injury.

    PubMed

    Newsome, Mary R; Durgerian, Sally; Mourany, Lyla; Scheibel, Randall S; Lowe, Mark J; Beall, Erik B; Koenig, Katherine A; Parsons, Michael; Troyanskaya, Maya; Reece, Christine; Wilde, Elisabeth; Fischer, Barbara L; Jones, Stephen E; Agarwal, Rajan; Levin, Harvey S; Rao, Stephen M

    2015-01-01

    Mild to moderate traumatic brain injury (TBI) due to blast exposure is frequently diagnosed in veterans returning from the wars in Iraq and Afghanistan. However, it is unclear whether neural damage resulting from blast TBI differs from that found in TBI due to blunt-force trauma (e.g., falls and motor vehicle crashes). Little is also known about the effects of blast TBI on neural networks, particularly over the long term. Because impairment in working memory has been linked to blunt-force TBI, the present functional magnetic resonance imaging (fMRI) study sought to investigate whether brain activation in response to a working memory task would discriminate blunt-force from blast TBI. Twenty-five veterans (mean age = 29.8 years, standard deviation = 6.01 years, 1 female) who incurred TBI due to blast an average of 4.2 years prior to enrollment and 25 civilians (mean age = 27.4 years, standard deviation = 6.68 years, 4 females) with TBI due to blunt-force trauma performed the Sternberg Item Recognition Task while undergoing fMRI. The task involved encoding 1, 3, or 5 items in working memory. A group of 25 veterans (mean age = 29.9 years, standard deviation = 5.53 years, 0 females) and a group of 25 civilians (mean age = 27.3 years, standard deviation = 5.81 years, 0 females) without history of TBI underwent identical imaging procedures and served as controls. Results indicated that the civilian TBI group and both control groups demonstrated a monotonic relationship between working memory set size and activation in the right caudate during encoding, whereas the blast TBI group did not (p < 0.05, corrected for multiple comparisons using False Discovery Rate). Blast TBI was also associated with worse performance on the Sternberg Item Recognition Task relative to the other groups, although no other group differences were found on neuropsychological measures of episodic memory, inhibition, and general processing speed. These results could not be

  1. Disruption of caudate working memory activation in chronic blast-related traumatic brain injury

    PubMed Central

    Newsome, Mary R.; Durgerian, Sally; Mourany, Lyla; Scheibel, Randall S.; Lowe, Mark J.; Beall, Erik B.; Koenig, Katherine A.; Parsons, Michael; Troyanskaya, Maya; Reece, Christine; Wilde, Elisabeth; Fischer, Barbara L.; Jones, Stephen E.; Agarwal, Rajan; Levin, Harvey S.; Rao, Stephen M.

    2015-01-01

    Mild to moderate traumatic brain injury (TBI) due to blast exposure is frequently diagnosed in veterans returning from the wars in Iraq and Afghanistan. However, it is unclear whether neural damage resulting from blast TBI differs from that found in TBI due to blunt-force trauma (e.g., falls and motor vehicle crashes). Little is also known about the effects of blast TBI on neural networks, particularly over the long term. Because impairment in working memory has been linked to blunt-force TBI, the present functional magnetic resonance imaging (fMRI) study sought to investigate whether brain activation in response to a working memory task would discriminate blunt-force from blast TBI. Twenty-five veterans (mean age = 29.8 years, standard deviation = 6.01 years, 1 female) who incurred TBI due to blast an average of 4.2 years prior to enrollment and 25 civilians (mean age = 27.4 years, standard deviation = 6.68 years, 4 females) with TBI due to blunt-force trauma performed the Sternberg Item Recognition Task while undergoing fMRI. The task involved encoding 1, 3, or 5 items in working memory. A group of 25 veterans (mean age = 29.9 years, standard deviation = 5.53 years, 0 females) and a group of 25 civilians (mean age = 27.3 years, standard deviation = 5.81 years, 0 females) without history of TBI underwent identical imaging procedures and served as controls. Results indicated that the civilian TBI group and both control groups demonstrated a monotonic relationship between working memory set size and activation in the right caudate during encoding, whereas the blast TBI group did not (p < 0.05, corrected for multiple comparisons using False Discovery Rate). Blast TBI was also associated with worse performance on the Sternberg Item Recognition Task relative to the other groups, although no other group differences were found on neuropsychological measures of episodic memory, inhibition, and general processing speed. These results could not be

  2. Reversal of aging-related emotional memory deficits by norepinephrine via regulating the stability of surface AMPA receptors.

    PubMed

    Luo, Yi; Zhou, Jun; Li, Ming-Xing; Wu, Peng-Fei; Hu, Zhuang-Li; Ni, Lan; Jin, You; Chen, Jian-Guo; Wang, Fang

    2015-04-01

    Aging-related emotional memory deficit is a well-known complication in Alzheimer's disease and normal aging. However, little is known about its molecular mechanism. To address this issue, we examined the role of norepinephrine (NE) and its relevant drug desipramine in the regulation of hippocampal long-term potentiation (LTP), surface expression of AMPA receptor, and associative fear memory in rats. We found that there was a defective regulation of NE content and AMPA receptor trafficking during fear conditioning, which were accompanied by impaired emotional memory and LTP in aged rats. Furthermore, we also found that the exogenous upregulation of NE ameliorated the impairment of LTP and emotional memory via enhancing AMPA receptor trafficking in aged rats, and the downregulation of NE impaired LTP in adult rats. Finally, acute treatment with NE or desipramine rescued the impaired emotional memory in aged rats. These results imply a pivotal role for NE in synaptic plasticity and associative fear memory in aging rats and suggest that desipramine is a potential candidate for treating aging-related emotional memory deficit.

  3. Neonatal anoxia in rats: hippocampal cellular and subcellular changes related to cell death and spatial memory.

    PubMed

    Takada, S H; dos Santos Haemmerle, C A; Motta-Teixeira, L C; Machado-Nils, A V; Lee, V Y; Takase, L F; Cruz-Rizzolo, R J; Kihara, A H; Xavier, G F; Watanabe, I-S; Nogueira, M I

    2015-01-22

    Neonatal anoxia in rodents has been used to understand brain changes and cognitive dysfunction following asphyxia. This study investigated the time-course of cellular and subcellular changes and hippocampal cell death in a non-invasive model of anoxia in neonatal rats, using Terminal deoxynucleotidyl transferase-mediated dUTP Nick End Labeling (TUNEL) to reveal DNA fragmentation, Fluoro-Jade® B (FJB) to show degenerating neurons, cleaved caspase-3 immunohistochemistry (IHC) to detect cells undergoing apoptosis, and transmission electron microscopy (TEM) to reveal fine ultrastructural changes related to cell death. Anoxia was induced by exposing postnatal day 1 (P1) pups to a flow of 100% gaseous nitrogen for 25 min in a chamber maintained at 37 °C. Control rats were similarly exposed to this chamber but with air flow instead of nitrogen. Brain changes following anoxia were evaluated at postnatal days 2, 14, 21 and 60 (P2, P14, P21 and P60). In addition, spatial reference memory following anoxia and control treatments was evaluated in the Morris water maze, starting at P60. Compared to their respective controls, P2 anoxic rats exhibited (1) higher TUNEL labeling in cornus ammonis (CA) 1 and the dentate gyrus (DG), (2) higher FJB-positive cells in the CA2-3, and (3) somato-dendritic swelling, mitochondrial injury and chromatin condensation in irregular bodies, as well as other subcellular features indicating apoptosis, necrosis, autophagy and excitotoxicity in the CA1, CA2-3 and DG, as revealed by TEM. At P14, P21 and P60, both groups showed small numbers of TUNEL-positive and FJB-positive cells. Stereological analysis at P2, P14, P21 and P60 revealed a lack of significant differences in cleaved caspase-3 IHC between anoxic and control subjects. These results suggest that the type of hippocampal cell death following neonatal anoxia is likely independent of caspase-3 activation. Neonatal anoxia induced deficits in acquisition and performance of spatial reference

  4. Alzheimer’s Disease and Age-Related Memory Decline (Preclinical)

    PubMed Central

    Terry, Alvin V.; Callahan, Patrick M.; Hall, Brandon; Webster, Scott J.

    2011-01-01

    An unfortunate result of the rapid rise in geriatric populations worldwide is the increasing prevalence of age-related cognitive disorders such as Alzheimer’s disease (AD). AD is a devastating neurodegenerative illness that is characterized by a profound impairment of cognitive function, marked physical disability, and an enormous economic burden on the afflicted individual, caregivers, and society in general. The rise in elderly populations is also resulting in an increase in individuals with related (potentially treatable) conditions such as “Mild Cognitive Impairment” (MCI) which is characterized by a less severe (but abnormal) level of cognitive impairment and a high-risk for developing dementia. Even in the absence of a diagnosable disorder of cognition (e.g., AD, MCI), the perception of increased forgetfulness and declining mental function is a clear source of apprehension in the elderly. This is a valid concern given that even a modest impairment of cognitive function is likely to be associated with significant disability in a rapidly evolving, technology-based society. Unfortunately, the currently available therapies designed to improve cognition (i.e., for AD and other forms of dementia) are limited by modest efficacy, adverse side effects, and their effects on cognitive function are not sustained over time. Accordingly, it is incumbent on the scientific community to develop safer and more effective therapies that improve and/or sustain cognitive function in the elderly allowing them to remain mentally active and productive for as long as possible. As diagnostic criteria for memory disorders evolve, the demand for pro-cognitive therapeutic agents is likely to surpass AD and dementia to include MCI and potentially even less severe forms of memory decline. The purpose of this review is to provide an overview of the contemporary therapeutic targets and preclinical pharmacologic approaches (with representative drug examples) designed to enhance memory

  5. Contribution of working memory processes to relational matching-to-sample performance in baboons (Papio papio).

    PubMed

    Maugard, Anaïs; Marzouki, Yousri; Fagot, Joël

    2013-11-01

    Recent studies of monkeys and apes have shown that these animals can solve relational-matching-to-sample (RMTS) problems, suggesting basic abilities for analogical reasoning. However, doubts remain as to the actual cognitive strategies adopted by nonhuman primates in this task. Here, we used dual-task paradigms to test 10 baboons in the RMTS problem under three conditions of memory load. Our three test conditions allowed different predictions, depending on the strategy (i.e., flat memorization of the percept, reencoding of the percept, or relational processing) that they might use to solve RMTS problems. Results support the idea that the baboons process both the items and the abstract (same and different) relations in this task.

  6. Age-related effects on the neural correlates of autobiographical memory retrieval.

    PubMed

    St Jacques, Peggy L; Rubin, David C; Cabeza, Roberto

    2012-07-01

    Older adults recall less episodically rich autobiographical memories (AM), however, the neural basis of this effect is not clear. Using functional MRI, we examined the effects of age during search and elaboration phases of AM retrieval. Our results suggest that the age-related attenuation in the episodic richness of AMs is associated with difficulty in the strategic retrieval processes underlying recovery of information during elaboration. First, age effects on AM activity were more pronounced during elaboration than search, with older adults showing less sustained recruitment of the hippocampus and ventrolateral prefrontal cortex (VLPFC) for less episodically rich AMs. Second, there was an age-related reduction in the modulation of top-down coupling of the VLPFC on the hippocampus for episodically rich AMs. In sum, the present study shows that changes in the sustained response and coupling of the hippocampus and prefrontal cortex (PFC) underlie age-related reductions in episodic richness of the personal past.

  7. Relational and procedural memory systems in the goldfish brain revealed by trace and delay eyeblink-like conditioning.

    PubMed

    Gómez, A; Rodríguez-Expósito, B; Durán, E; Martín-Monzón, I; Broglio, C; Salas, C; Rodríguez, F

    2016-12-01

    The presence of multiple memory systems supported by different neural substrata has been demonstrated in animal and human studies. In mammals, two variants of eyeblink classical conditioning, differing only in the temporal relationships between the conditioned stimulus (CS) and the unconditioned stimulus (US), have been widely used to study the neural substrata of these different memory systems. Delay conditioning, in which both stimuli coincide in time, depends on a non-relational memory system supported by the cerebellum and associated brainstem circuits. In contrast, trace conditioning, in which a stimulus-free time gap separates the CS and the US, requires a declarative or relational memory system, thus depending on forebrain structures in addition to the cerebellum. The distinction between the explicit or relational and the implicit or procedural memory systems that support trace and delay classical conditioning has been extensively studied in mammals, but studies in other vertebrate groups are relatively scarce. In the present experiment we analyzed the differential involvement of the cerebellum and the telencephalon in delay and trace eyeblink-like classical conditioning in goldfish. The results show that whereas the cerebellum lesion prevented the eyeblink-like conditioning in both procedures, the telencephalon ablation impaired exclusively the acquisition of the trace conditioning. These data showing that comparable neural systems support delay and trace eyeblink conditioning in teleost fish and mammals suggest that these separate memory systems and their neural bases could be a shared ancestral brain feature of the vertebrate lineage.

  8. Age-related effects on verbal and visuospatial memory are mediated by theta and alpha II rhythms.

    PubMed

    Reichert, Johanna Louise; Kober, Silvia Erika; Witte, Matthias; Neuper, Christa; Wood, Guilherme

    2016-01-01

    Both electrical brain activity during rest and memory functions change across the lifespan. Moreover, electrical brain activity is associated with memory functions. However, the interplay between all these effects has been investigated only scarcely. The present study investigated the extent to which the power of resting-state electroencephalographic (EEG) frequencies mediates the impact of aging on verbal and visuospatial memory. Seventy healthy participants with 22 to 83years of age completed a visuospatial and verbal learning and memory test and provided eyes-open and eyes-closed resting-state EEG data. Robust age-related effects on behavioral and EEG data were observed. Mediation analyses showed that the relative power of the theta (4-8Hz) frequency band in fronto-central locations partly explained the negative age-related effect on delayed recall in the verbal memory task. The relative power of the alpha II (10-12Hz) frequency band in mainly parietal locations partly explained the negative impact of age on immediate and delayed recall in the visuospatial task. Results indicate that spontaneous brain activity carries specific information about aging processes and predicts the level of competence in verbal and visuospatial memory tasks.

  9. Daydreaming style moderates the relation between working memory and mind wandering: Integrating two hypotheses.

    PubMed

    Marcusson-Clavertz, David; Cardeña, Etzel; Terhune, Devin Blair

    2016-03-01

    Mind wandering-mentation unrelated to one's current activity and surroundings-is a ubiquitous phenomenon, but seemingly competing ideas have been proposed regarding its relation to executive cognitive processes. The control-failure hypothesis postulates that executive processes prevent mind wandering, whereas the global availability hypothesis proposes that mind wandering requires executive resources, and thus an excess of such resources enables mind wandering. Here, we examined whether these hypotheses could be reconciled by considering the moderating influence of daydreaming style. We expected that executive resources would be positively related to mind wandering in those who typically experience positive mind wandering mentation, but negatively related in those who typically experience negative mentation. One hundred eleven participants reported mind wandering over 4 days using experience sampling and completed the sustained attention to response task (SART), the symmetry span task, and the Stroop task. There was a significant interaction between working memory and negative, but not positive, daydreaming style on mind wandering: Working memory related positively to mind wandering in those with a low negative style, but negatively in those with a high negative style. In contrast, poor Stroop performance significantly predicted increased mind wandering, but only in those with a low positive style. SART responses did not predict mind wandering although the relation was suggestively enhanced as the difficulty of daily life activities increased, indicating that the SART is more generalizable to high-demanding than low-demanding activities. These results suggest that the content and context of mind wandering episodes play important roles in the relation between executive processes and mind wandering.

  10. Amifostine ameliorates recognition memory defect in acute radiation syndrome caused by relatively low-dose of gamma radiation.

    PubMed

    Lee, Hae-June; Kim, Joong-Sun; Song, Myoung-Sub; Seo, Heung-Sik; Yang, Miyoung; Kim, Jong Choon; Jo, Sung-Kee; Shin, Taekyun; Moon, Changjong; Kim, Sung-Ho

    2010-03-01

    This study examined whether amifostine (WR-2721) could attenuate memory impairment and suppress hippocampal neurogenesis in adult mice with the relatively low-dose exposure of acute radiation syndrome (ARS). These were assessed using object recognition memory test, the terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling assay, and immunohistochemical markers of neurogenesis [Ki-67 and doublecortin (DCX)]. Amifostine treatment (214 mg/kg, i.p.) prior to irradiation significantly attenuated the recognition memory defect in ARS, and markedly blocked the apoptotic death and decrease of Ki-67- and DCX-positive cells in ARS. Therefore, amifostine may attenuate recognition memory defect in a relatively low-dose exposure of ARS in adult mice, possibly by inhibiting a detrimental effect of irradiation on hippocampal neurogenesis.

  11. Selective alterations of neurons and circuits related to early memory loss in Alzheimer's disease.

    PubMed

    Llorens-Martín, Maria; Blazquez-Llorca, Lidia; Benavides-Piccione, Ruth; Rabano, Alberto; Hernandez, Felix; Avila, Jesus; DeFelipe, Javier

    2014-01-01

    A progressive loss of episodic memory is a well-known clinical symptom that characterizes Alzheimer's disease (AD). The beginning of this loss of memory has been associated with the very early, pathological accumulation of tau and neuronal degeneration observed in the entorhinal cortex (EC). Tau-related pathology is thought to then spread progressively to the hippocampal formation and other brain areas as the disease progresses. The major cortical afferent source of the hippocampus and dentate gyrus is the EC through the perforant pathway. At least two main circuits participate in the connection between EC and the hippocampus; one originating in layer II and the other in layer III of the EC giving rise to the classical trisynaptic (ECII → dentate gyrus → CA3 → CA1) and monosynaptic (ECIII → CA1) circuits. Thus, the study of the early pathological changes in these circuits is of great interest. In this review, we will discuss mainly the alterations of the granule cell neurons of the dentate gyrus and the atrophy of CA1 pyramidal neurons that occur in AD in relation to the possible differential alterations of these two main circuits.

  12. Selective alterations of neurons and circuits related to early memory loss in Alzheimer’s disease

    PubMed Central

    Llorens-Martín, Maria; Blazquez-Llorca, Lidia; Benavides-Piccione, Ruth; Rabano, Alberto; Hernandez, Felix; Avila, Jesus; DeFelipe, Javier

    2014-01-01

    A progressive loss of episodic memory is a well-known clinical symptom that characterizes Alzheimer’s disease (AD). The beginning of this loss of memory has been associated with the very early, pathological accumulation of tau and neuronal degeneration observed in the entorhinal cortex (EC). Tau-related pathology is thought to then spread progressively to the hippocampal formation and other brain areas as the disease progresses. The major cortical afferent source of the hippocampus and dentate gyrus is the EC through the perforant pathway. At least two main circuits participate in the connection between EC and the hippocampus; one originating in layer II and the other in layer III of the EC giving rise to the classical trisynaptic (ECII → dentate gyrus → CA3 → CA1) and monosynaptic (ECIII → CA1) circuits. Thus, the study of the early pathological changes in these circuits is of great interest. In this review, we will discuss mainly the alterations of the granule cell neurons of the dentate gyrus and the atrophy of CA1 pyramidal neurons that occur in AD in relation to the possible differential alterations of these two main circuits. PMID:24904307

  13. Event-related brain potential correlates of two states of conscious awareness in memory

    PubMed Central

    Düzel, Emrah; Yonelinas, Andrew P.; Mangun, George R.; Heinze, Hans-Jochen; Tulving, Endel

    1997-01-01

    We report an event-related potential (ERP) experiment of human recognition memory that explored the relation between conscious awareness and electrophysiological activity of the brain. We recorded ERPs from healthy adults while they made “remember” and “know” recognition judgments about previously seen words. These two kinds of judgments reflect “autonoetic” and “noetic” awareness, respectively. The ERP effects differed between the two kinds of awareness while they were similar for “true” and “false” recognition. Noetic awareness was associated with a temporoparietal positivity in the N400 range (325–600 ms) and a late (600–1,000 ms) frontocentral negativity, whereas autonoetic awareness was associated with a widespread, late, bifrontal and left parietotemporal (600–1000 ms) positivity. In the very late (1,300–1,900 ms) time window, a right frontal positivity was observed for both remember and know judgments of both true and false targets. These results provide physiological evidence for two types of conscious awareness in episodic memory retrieval. PMID:9159185

  14. Age-Related Declines in Early Sensory Memory: Identification of Rapid Auditory and Visual Stimulus Sequences

    PubMed Central

    Fogerty, Daniel; Humes, Larry E.; Busey, Thomas A.

    2016-01-01

    Age-related temporal-processing declines of rapidly presented sequences may involve contributions of sensory memory. This study investigated recall for rapidly presented auditory (vowel) and visual (letter) sequences presented at six different stimulus onset asynchronies (SOA) that spanned threshold SOAs for sequence identification. Younger, middle-aged, and older adults participated in all tasks. Results were investigated at both equivalent performance levels (i.e., SOA threshold) and at identical physical stimulus values (i.e., SOAs). For four-item sequences, results demonstrated best performance for the first and last items in the auditory sequences, but only the first item for visual sequences. For two-item sequences, adults identified the second vowel or letter significantly better than the first. Overall, when temporal-order performance was equated for each individual by testing at SOA thresholds, recall accuracy for each position across the age groups was highly similar. These results suggest that modality-specific processing declines of older adults primarily determine temporal-order performance for rapid sequences. However, there is some evidence for a second amodal processing decline in older adults related to early sensory memory for final items in a sequence. This selective deficit was observed particularly for longer sequence lengths and was not accounted for by temporal masking. PMID:27199737

  15. Simulating Navigation with Virtual 3d Geovisualizations - a Focus on Memory Related Factors

    NASA Astrophysics Data System (ADS)

    Lokka, I.; Çöltekin, A.

    2016-06-01

    The use of virtual environments (VE) for navigation-related studies, such as spatial cognition and path retrieval has been widely adopted in cognitive psychology and related fields. What motivates the use of VEs for such studies is that, as opposed to real-world, we can control for the confounding variables in simulated VEs. When simulating a geographic environment as a virtual world with the intention to train navigational memory in humans, an effective and efficient visual design is important to facilitate the amount of recall. However, it is not yet clear what amount of information should be included in such visual designs intended to facilitate remembering: there can be too little or too much of it. Besides the amount of information or level of detail, the types of visual features (`elements' in a visual scene) that should be included in the representations to create memorable scenes and paths must be defined. We analyzed the literature in cognitive psychology, geovisualization and information visualization, and identified the key factors for studying and evaluating geovisualization designs for their function to support and strengthen human navigational memory. The key factors we identified are: i) the individual abilities and age of the users, ii) the level of realism (LOR) included in the representations and iii) the context in which the navigation is performed, thus specific tasks within a case scenario. Here we present a concise literature review and our conceptual development for follow-up experiments.

  16. Encoding-related EEG oscillations during memory formation are modulated by mood state

    PubMed Central

    Bajbouj, Malek

    2014-01-01

    Mood states have a strong impact on how we process incoming information. It has been proposed that positive mood facilitates elaborative, relational encoding, whereas negative mood promotes a more careful, stimulus-driven encoding style. Previous electrophysiological studies have linked successful information encoding to power increases in slow (<8 Hz) delta/theta and fast (>30 Hz) gamma oscillations, as well as to power decreases in midrange (8–30 Hz) alpha/beta oscillations. Whether different mood states modulate encoding-related oscillations has not been investigated yet. In order to address this question, we used an experimental mood induction procedure and recorded electroencephalograms from 20 healthy participants while they performed a free recall memory task after positive and negative mood induction. We found distinct oscillatory patterns in positive and negative mood. Successful encoding in positive mood was accompanied by widespread power increases in the delta band, whereas encoding success in negative mood was specifically accompanied by frontal power decreases in the beta band. On the behavioral level, memory performance was enhanced in positive mood. Our findings show that mood differentially modulates the neural correlates of successful information encoding and thus contribute to an understanding of how mood shapes different processing styles. PMID:24464848

  17. Memory Distortion and Its Avoidance: An Event-Related Potentials Study on False Recognition and Correct Rejection

    PubMed Central

    Beato, Maria Soledad

    2016-01-01

    Memory researchers have long been captivated by the nature of memory distortions and have made efforts to identify the neural correlates of true and false memories. However, the underlying mechanisms of avoiding false memories by correctly rejecting related lures remains underexplored. In this study, we employed a variant of the Deese/Roediger-McDermott paradigm to explore neural signatures of committing and avoiding false memories. ERP were obtained for True recognition, False recognition, Correct rejection of new items, and, more importantly, Correct rejection of related lures. With these ERP data, early-frontal, left-parietal, and late right-frontal old/new effects (associated with familiarity, recollection, and monitoring processes, respectively) were analysed. Results indicated that there were similar patterns for True and False recognition in all three old/new effects analysed in our study. Also, False recognition and Correct rejection of related lures activities seemed to share common underlying familiarity-based processes. The ERP similarities between False recognition and Correct rejection of related lures disappeared when recollection processes were examined because only False recognition presented a parietal old/new effect. This finding supported the view that actual false recollections underlie false memories, providing evidence consistent with previous behavioural research and with most ERP and neuroimaging studies. Later, with the onset of monitoring processes, False recognition and Correct rejection of related lures waveforms presented, again, clearly dissociated patterns. Specifically, False recognition and True recognition showed more positive going patterns than Correct rejection of related lures signal and Correct rejection of new items signature. Since False recognition and Correct rejection of related lures triggered familiarity-recognition processes, our results suggest that deciding which items are studied is based more on recollection

  18. "Plateau"-related summary statistics are uninformative for comparing working memory models.

    PubMed

    van den Berg, Ronald; Ma, Wei Ji

    2014-10-01

    Performance on visual working memory tasks decreases as more items need to be remembered. Over the past decade, a debate has unfolded between proponents of slot models and slotless models of this phenomenon (Ma, Husain, Bays (Nature Neuroscience 17, 347-356, 2014). Zhang and Luck (Nature 453, (7192), 233-235, 2008) and Anderson, Vogel, and Awh (Attention, Perception, Psychophys 74, (5), 891-910, 2011) noticed that as more items need to be remembered, "memory noise" seems to first increase and then reach a "stable plateau." They argued that three summary statistics characterizing this plateau are consistent with slot models, but not with slotless models. Here, we assess the validity of their methods. We generated synthetic data both from a leading slot model and from a recent slotless model and quantified model evidence using log Bayes factors. We found that the summary statistics provided at most 0.15 % of the expected model evidence in the raw data. In a model recovery analysis, a total of more than a million trials were required to achieve 99 % correct recovery when models were compared on the basis of summary statistics, whereas fewer than 1,000 trials were sufficient when raw data were used. Therefore, at realistic numbers of trials, plateau-related summary statistics are highly unreliable for model comparison. Applying the same analyses to subject data from Anderson et al. (Attention, Perception, Psychophys 74, (5), 891-910, 2011), we found that the evidence in the summary statistics was at most 0.12 % of the evidence in the raw data and far too weak to warrant any conclusions. The evidence in the raw data, in fact, strongly favored the slotless model. These findings call into question claims about working memory that are based on summary statistics.

  19. Music mnemonics aid Verbal Memory and Induce Learning – Related Brain Plasticity in Multiple Sclerosis

    PubMed Central

    Thaut, Michael H.; Peterson, David A.; McIntosh, Gerald C.; Hoemberg, Volker

    2014-01-01

    Recent research on music and brain function has suggested that the temporal pattern structure in music and rhythm can enhance cognitive functions. To further elucidate this question specifically for memory, we investigated if a musical template can enhance verbal learning in patients with multiple sclerosis (MS) and if music-assisted learning will also influence short-term, system-level brain plasticity. We measured systems-level brain activity with oscillatory network synchronization during music-assisted learning. Specifically, we measured the spectral power of 128-channel electroencephalogram (EEG) in alpha and beta frequency bands in 54 patients with MS. The study sample was randomly divided into two groups, either hearing a spoken or a musical (sung) presentation of Rey’s auditory verbal learning test. We defined the “learning-related synchronization” (LRS) as the percent change in EEG spectral power from the first time the word was presented to the average of the subsequent word encoding trials. LRS differed significantly between the music and the spoken conditions in low alpha and upper beta bands. Patients in the music condition showed overall better word memory and better word order memory and stronger bilateral frontal alpha LRS than patients in the spoken condition. The evidence suggests that a musical mnemonic recruits stronger oscillatory network synchronization in prefrontal areas in MS patients during word learning. It is suggested that the temporal structure implicit in musical stimuli enhances “deep encoding” during verbal learning and sharpens the timing of neural dynamics in brain networks degraded by demyelination in MS. PMID:24982626

  20. Anxiety-related threat bias in recognition memory: the moderating effect of list composition and semantic-similarity effects.

    PubMed

    White, Corey N; Ratcliff, Roger; Vasey, Michael W

    2015-08-05

    Individuals with high anxiety show bias for threatening information, but it is unclear whether this bias affects memory. Recognition memory studies have shown biases for recognising and rejecting threatening items in anxiety, prompting the need to identify moderating factors of this effect. This study focuses on the role of semantic similarity: the use of many semantically related threatening words could increase familiarity for those items and obscure anxiety-related differences in memory. To test this, two recognition memory experiments varied the proportion of threatening words in lists to manipulate the semantic-similarity effects. When similarity effects were reduced, participants with high trait anxiety were biased to respond "new" to threatening words, whereas when similarity effects were strong there was no effect of anxiety on memory bias. Analysis of the data with the drift diffusion model showed that the bias was due to differences in processing of the threatening stimuli rather than a simple response bias. These data suggest that the semantic similarity of the threatening words significantly affects the presence or absence of anxiety-related threat bias in recognition memory. The results indicate that trait anxiety is associated with a bias to decide that threatening stimuli were not previously studied, but only when semantic-similarity effects are controlled. Implications for theories of anxiety and future studies in this domain are discussed.

  1. Event-related potential study of intentional and incidental retrieval of item and source memory during early childhood.

    PubMed

    Robey, Alison; Riggins, Tracy

    2016-07-01

    The event related potential (ERP) technique is a useful methodology for studying neural changes underlying memory development during childhood. However, systematic comparisons of differences in memory tasks and retrieval demands are lacking. To address this gap, the present study explored the effects of memory task (i.e., item versus source) and retrieval paradigm (i.e., intentional versus incidental) on 4- to 5-year-old children's memory performance and associated electrophysiological responses. Children were familiarized with items in a play-like setting and then asked to retrieve item or source memory details while their brain activity was recorded (intentional retrieval) or while they passively viewed images of the items with no explicit task (incidental retrieval). Memory assessments for the incidental groups followed ERP recording. Analyses of the ERP data suggested that the brain's response during intentional retrieval of source information differed from the other three conditions. These results are discussed within a two-component framework of memory development (e.g., Shing et al., 2010), and implications for future methodological decisions are presented. © 2016 Wiley Periodicals, Inc. Dev Psychobiol 58: 556-567, 2016.

  2. Relations between Working Memory and Emergent Writing among Preschool-Aged Children

    ERIC Educational Resources Information Center

    Hoskyn, Maureen; Tzoneva, Irina

    2008-01-01

    The authors examined the nature of the working memory system that underlies age differences of young, preschool-aged children. Measures of working memory, short-term memory, articulation speed, general intelligence, and writing were administered to 166 Canadian preschool-aged children aged 3 to 5 years. Findings generally support the hypothesis…

  3. Relations between the Test of Variables of Attention (TOVA) and the Children's Memory Scale (CMS)

    ERIC Educational Resources Information Center

    Riccio, Cynthia A.; Garland, Beth H.; Cohen, Morris J.

    2007-01-01

    Objective: There is considerable overlap in the constructs of attention and memory. The objective of this study was to examine the relationship between the Test of Variables of Attention (TOVA), a measure of attention, to components of memory and learning as measured by the Children's Memory Scale (CMS). Method: Participants (N = 105) were…

  4. A Reevaluation of Age-Related Changes in Associative Memory Organization.

    ERIC Educational Resources Information Center

    Lindauer, Barbara K.; Paris, Scott G.

    This paper focuses on a study which replicates and extends earlier work employing a recognition memory paradigm to investigate children's memory and developmental changes in dominant word associations. On the recognition test the implicit associative response can lead to better memory for the original items (this is the hit rate), and it can also…

  5. Developmental Differences in Relations between Episodic Memory and Hippocampal Subregion Volume during Early Childhood

    ERIC Educational Resources Information Center

    Riggins, Tracy; Blankenship, Sarah L.; Mulligan, Elizabeth; Rice, Katherine; Redcay, Elizabeth

    2015-01-01

    Episodic memory shows striking improvement during early childhood. However, neural contributions to these behavioral changes are not well understood. This study examined associations between episodic memory and volume of subregions (head, body, and tail) of the hippocampus--a structure known to support episodic memory in school-aged children and…

  6. Putting the Pieces Together: The Role of Dorsolateral Prefrontal Cortex in Relational Memory Encoding

    ERIC Educational Resources Information Center

    Blumenfeld, Robert S.; Parks, Colleen M.; Yonelinas, Andrew P.; Ranganath, Charan

    2011-01-01

    Results from fMRI have strongly supported the idea that the ventrolateral PFC (VLPFC) contributes to successful memory formation, but the role the dorsolateral PFC (DLPFC) in memory encoding is more controversial. Some findings suggest that the DLPFC is recruited when one is processing relationships between items in working memory, and this…

  7. Infants’ Visual Recognition Memory for a Series of Categorically Related Items

    ERIC Educational Resources Information Center

    Oakes, Lisa M.; Kovack-Lesh, Kristine A.

    2013-01-01

    Six-month-old infants' ("N" = 168) memory for individual items in a categorized list (e.g., images of dogs or cats) was examined to investigate the interactions between visual recognition memory, working memory, and categorization. In Experiments 1 and 2, infants were familiarized with six different cats or dogs, presented one at a time…

  8. Task-relevancy effects on movement-related gating are modulated by continuous theta-burst stimulation of the dorsolateral prefrontal cortex and primary somatosensory cortex.

    PubMed

    Brown, Katlyn E; Ferris, Jennifer K; Amanian, Mohammad A; Staines, W Richard; Boyd, Lara A

    2015-03-01

    Movement-related gating ensures that decreased somatosensory information from external stimulation reaches the cortex during movement when compared to resting levels; however, gating may be influenced by task-relevant manipulations, such that increased sensory information ascends to the cortex when information is relevant to goal-based actions. These task-relevancy effects are hypothesized to be controlled by a network involving the dorsolateral prefrontal cortex (DLPFC) based on this region's known role in selective attention, modulating the primary somatosensory cortex (S1). The purpose of the current study was first to verify task-relevancy influences on movement-related gating in the upper limb, and second to test the contribution of the DLPFC and the primary somatosensory cortex (S1) to these relevancy effects. Ten healthy participants received median nerve stimulation at the left wrist during three conditions: rest, task-irrelevant movement, and task-relevant movement. Cortical responses to median nerve stimulations were measured in the form of somatosensory evoked potentials (SEPs). The three conditions were collected on a baseline day and on two separate days following continuous theta-burst (cTBS), which transiently reduces cortical excitability, over either the contralateral S1 or DLPFC. Results demonstrated a significant interaction between stimulation and condition, with a priori contrasts revealing that cTBS over either S1 or DLPFC diminished the relevancy-based modulation of SEP amplitudes; however, the degree of this effect was different. These results indicate that DLPFC influences over S1 are involved in the facilitation of relevant sensory information during movement.

  9. Acute effects of nicotine administration during prospective memory, an event related fMRI study.

    PubMed

    Rusted, Jennifer; Ruest, Torsten; Gray, Marcus A

    2011-07-01

    We previously demonstrated that stimulating neuronal nicotinic acetylcholine receptors modulates prospective memory (PM), the ability to remember and implement a prior intention. Here we used fMRI to explore the neuronal correlates of acute nicotinic (1mg) modulation during PM, employing a double blind, valence-matched placebo-controlled design, and a solely event-related analysis. Eight healthy adults completed on two occasions (1 week washout) a simple attentional task containing infrequent PM trials. PM activated bilateral parietal, prefrontal (BA10) and anterior cingulate, and deactivated genual cingulate and medial prefrontal regions. Further, acute nicotine administration decreased activity within a largely overlapping right parietal region. This data validates a purely event-related approach to exploring PM, and suggests procholinergic modulation of PM by parietal rather than BA10/frontal regions.

  10. High-resolution ERP mapping of cortical activation related to implicit object-location memory.

    PubMed

    Murphy, Jonathan S; Wynne, Ciara E; O'Rourke, Edel M; Commins, Seán; Roche, Richard A P

    2009-12-01

    High-density event-related potentials (ERPs) were recorded during an object recognition task which involved task-irrelevant changes in the location of studied objects. Participants categorised objects as studied or novel while data were analysed to ascertain the effect of the location changes on performance and waveform topography. Our results indicate that humans can classify objects faster and more accurately when using implicit spatial memory. Individual differences observed in object recognition proficiency were absent if objects were presented in their 'correct' location. In a second experiment we replicated the behavioural findings while manipulating viewpoint to discount scene recognition as an underlying factor. We propose a model which includes activation of the right medial temporal lobe prior to P300 elicitation to account for the prophylactic effect of implicit processing on object recognition. Hemispheric differences in parietal componentry dependant on sex of participant were also observed and are discussed in relation to differential strategies.

  11. Recognition memory for object form and object location: an event-related potential study.

    PubMed

    Mecklinger, A; Meinshausen, R M

    1998-09-01

    In this study, the processes associated with retrieving object forms and object locations from working memory were examined with the use of simultaneously recorded event-related potential (ERP) activity. Subjects memorized object forms and their spatial locations and made either object-based or location-based recognition judgments. In Experiment 1, recognition performance was higher for object locations than for object forms. Old responses evoked more positive-going ERP activity between 0.3 and 1.8 sec poststimulus than did new responses. The topographic distribution of these old/new effects in the P300 time interval was task specific, with object-based recognition judgments being associated with anteriorly focused effects and location-based judgments with posteriorly focused effects. Late old/new effects were dominant at right frontal recordings. Using an interference paradigm, it was shown in Experiment 2 that visual representations were used to rehearse both object forms and object locations in working memory. The results of Experiment 3 indicated that the observed differential topographic distributions of the old/new effects in the P300 time interval are unlikely to reflect differences between easy and difficult recognition judgments. More specific effects were obtained for a subgroup of subjects for which the processing characteristics during location-based judgments presumably were similar to those in Experiment 1. These data, together with those from Experiment 1, indicate that different brain areas are engaged in retrieving object forms and object locations from working memory. Further analyses support the view that retrieval of object forms relies on conceptual semantic representation, whereas retrieving object locations is based on structural representations of spatial information. The effects in the later time intervals may play a functional role in post-retrieval processing, such as recollecting information from the study episode or other processes

  12. Judgments relative to patterns: how temporal sequence patterns affect judgments and memory.

    PubMed

    Kusev, Petko; Ayton, Peter; van Schaik, Paul; Tsaneva-Atanasova, Krasimira; Stewart, Neil; Chater, Nick

    2011-12-01

    Six experiments studied relative frequency judgment and recall of sequentially presented items drawn from 2 distinct categories (i.e., city and animal). The experiments show that judged frequencies of categories of sequentially encountered stimuli are affected by certain properties of the sequence configuration. We found (a) a first-run effect whereby people overestimated the frequency of a given category when that category was the first repeated category to occur in the sequence and (b) a dissociation between judgments and recall; respondents may judge 1 event more likely than the other and yet recall more instances of the latter. Specifically, the distribution of recalled items does not correspond to the frequency estimates for the event categories, indicating that participants do not make frequency judgments by sampling their memory for individual items as implied by other accounts such as the availability heuristic (Tversky & Kahneman, 1973) and the availability process model (Hastie & Park, 1986). We interpret these findings as reflecting the operation of a judgment heuristic sensitive to sequential patterns and offer an account for the relationship between memory and judged frequencies of sequentially encountered stimuli.

  13. Event-related potential correlates of interference effects on recognition memory.

    PubMed

    Norman, Kenneth A; Tepe, Katharine; Nyhus, Erika; Curran, Tim

    2008-02-01

    The question of interference (how new learning affects previously acquired knowledge and vice versa) is a central theoretical issue in episodic memory research, but very few human neuroimaging studies have addressed this question. Here, we used event-related potentials (ERPs) to test the predictions of the complementary learning systems (CLS) model regarding how list strength manipulations (strengthening some, but not all, items on a study list) affect recognition memory. Our analysis focused on the FN400 old-new effect, a hypothesized ERP correlate of familiarity-based recognition, and the parietal old-new effect, a hypothesized ERP correlate of recollection-based recognition. As is predicted by the CLS model, increasing list strength selectively reduced the ERP correlate of recollection-based discrimination, leaving the ERP correlate of familiarity-based discrimination intact. In a second experiment, we obtained converging evidence for the CLS model's predictions, using a remember/know test: Increasing list strength reduced recollection-based discrimination but did not reduce familiarity-based discrimination.

  14. Age-related differences in inhibitory control and memory updating in boys with Asperger syndrome.

    PubMed

    Weiss, Elisabeth M; Gschaidbauer, Bianca; Kaufmann, Liane; Fink, Andreas; Schulter, Günter; Mittenecker, Erich; Papousek, Ilona

    2016-12-26

    Deficits in specific executive domains are highly prevalent in autism spectrum disorder; however, age-related improvements in executive functions (reflecting prefrontal maturational changes) have been reported even in individuals diagnosed with autism. The current study examined two components of cognitive flexibility (inhibition of prepotent responses and memory monitoring/updating) by using a random-motor-generation task (MPT) in a group of 23 boys with Asperger syndrome (AS) and 23 matched healthy controls. We found poorer inhibition and more repetitive responses in younger AS children solely, but comparable memory monitoring/updating skills across groups. Overall, our findings correspond well with previous studies and reveal that even in AS specific EFs may improve with age and, thus, call for a more differentiated view of executive (dys) function profiles in children diagnosed with AS. Tests such as the random-motor-generation task may help to disentangle more specific processes of executive deficits in autism spectrum disorder as compared to the more classical tests.

  15. The Frequency of Involuntary Autobiographical Memories and Future Thoughts in Relation to Daydreaming, Emotional Distress, and Age

    PubMed Central

    Berntsen, Dorthe; Rubin, David C.; Salgado, Sinue

    2015-01-01

    We introduce a new scale, the Involuntary Autobiographical Memory Inventory (IAMI), for measuring the frequency of involuntary autobiographical memories and involuntary future thoughts. Using the scale in relation to other psychometric and demographic measures provided three important, novel findings. First, the frequency of involuntary and voluntary memories and future thoughts are similarly related to general measures of emotional distress. This challenges the idea that the involuntary mode is uniquely associated with emotional distress. Second, the frequency of involuntary autobiographical remembering does not decline with age, whereas measures of daydreaming, suppression of unwanted thoughts and dissociative experiences all do. Thus, involuntary autobiographical remembering relates differently to aging than daydreaming and other forms of spontaneous and uncontrollable thoughts. Third, unlike involuntary autobiographical remembering, the frequency of future thoughts does decrease with age. This finding underscores the need for examining past and future mental time travel in relation to aging and life span development. PMID:26241025

  16. Two case studies illustrating how relatively selective hippocampal lesions in humans can have quite different effects on memory.

    PubMed

    Holdstock, J S; Parslow, D M; Morris, R G; Fleminger, S; Abrahams, S; Denby, C; Montaldi, D; Mayes, A R

    2008-01-01

    Two patients, with magnetic resonance imaging (MRI)-confirmed relatively selective hippocampal damage, showed distinct patterns of performance on tests of recall, item recognition, and associative recognition. Patient AC showed a mean bilateral volume reduction of the hippocampus of 28%, but displayed no memory deficit. Both recall and recognition memory were unimpaired. In contrast, patient PR, who showed a mean bilateral hippocampal volume reduction of 59%, was more consistently impaired on recall than recognition tests, although his recognition scores were highly variable. Patients AC and PR illustrate how variable the memory deficit following seemingly selective hippocampal damage can be in humans. They highlight the need for more sophisticated imaging in future studies if the human hippocampus' role in memory is to be fully identified.

  17. Reward expectancy-related prefrontal neuronal activities: are they neural substrates of "affective" working memory?

    PubMed

    Watanabe, Masataka; Hikosaka, Kazuo; Sakagami, Masamichi; Shirakawa, Shu-ichiro

    2007-01-01

    Primate prefrontal delay neurons are involved in retaining task-relevant cognitive information in working memory (WM). Recent studies have also revealed primate prefrontal delay neurons that are related to reward/omission-of-reward expectancy. Such reward-related delay activities might constitute "affective WM" (Davidson, 2002). "Affective" and "cognitive" WM are both concerned with representing not what is currently being presented, but rather what was presented previously or might be presented in the future. However, according to the original and widely accepted definition, WM is the "temporary storage and manipulation of information for complex cognitive tasks". Reward/omission-of-reward expectancy-related neuronal activity is neither prerequisite nor essential for accurate task performance; thus, such activity is not considered to comprise the neural substrates of WM. Also, "affective WM" might not be an appropriate usage of the term "WM". We propose that WM- and reward/omission-of-reward expectancy-related neuronal activity are concerned with representing which response should be performed in order to attain a goal (reward) and the goal of the response, respectively. We further suggest that the prefrontal cortex (PFC) plays a crucial role in the integration of cognitive (for example, WM-related) and motivational (for example, reward expectancy-related) operations for goal-directed behaviour. The PFC could then send this integrated information to other brain areas to control the behaviour.

  18. Distinct Neural Substrates for Maintaining Locations and Spatial Relations in Working Memory

    PubMed Central

    Blacker, Kara J.; Courtney, Susan M.

    2016-01-01

    Previous work has demonstrated a distinction between maintenance of two types of spatial information in working memory (WM): spatial locations and spatial relations. While a body of work has investigated the neural mechanisms of sensory-based information like spatial locations, little is known about how spatial relations are maintained in WM. In two experiments, we used fMRI to investigate the involvement of early visual cortex in the maintenance of spatial relations in WM. In both experiments, we found less quadrant-specific BOLD activity in visual cortex when a single spatial relation, compared to a single spatial location, was held in WM. Also across both experiments, we found a consistent set of brain regions that were differentially activated during maintenance of locations vs. relations. Maintaining a location, compared to a relation, was associated with greater activity in typical spatial WM regions like posterior parietal cortex and prefrontal regions. Whereas maintaining a relation, compared to a location, was associated with greater activity in the parahippocampal gyrus and precuneus/retrosplenial cortex. Further, in Experiment 2 we manipulated WM load and included trials where participants had to maintain three spatial locations or relations. Under this high load condition, the regions sensitive to locations vs. relations were somewhat different than under low load. We also identified regions that were sensitive to load specifically for location or relation maintenance, as well as overlapping regions sensitive to load more generally. These results suggest that the neural substrates underlying WM maintenance of spatial locations and relations are distinct from one another and that the neural representations of these distinct types of spatial information change with load. PMID:27932963

  19. Dose-related Effects of Salvinorin A in Humans: Dissociative, Hallucinogenic, and Memory Effects

    PubMed Central

    MacLean, Katherine A.; Johnson, Matthew W.; Reissig, Chad J.; Prisinzano, Thomas E.; Griffiths, Roland R.

    2012-01-01

    Rationale Salvinorin A is a kappa opioid agonist and the principal psychoactive constituent of the plant Salvia divinorum, which has increased in popularity as a recreational drug over the past decade. Few human studies have examined salvinorin A. Objective This double-blind, placebo-controlled study evaluated the dose-related effects of inhaled salvinorin A in individuals with histories of hallucinogen use. Methods Eight healthy hallucinogen-using adults inhaled up to 16 doses of salvinorin A (0.375 - 21 μg/kg) in ascending order. Physiological, behavioral, and subjective effects were assessed every 2 min for 60 min after administration. Qualitative subjective effects were assessed retrospectively via questionnaires at the end of sessions. Persisting effects were assessed 1 month later. Results Orderly dose-related effects peaked at 2 min and then rapidly dissipated, replicating previous findings. Subjective effects were intense, with maximal drug strength ratings or unresponsiveness frequently observed at high doses. Questionnaires assessing qualitative effects (Hallucinogen Rating Scale, Pharmacological Class Questionnaire) suggested some overlap with serotonergically mediated classic hallucinogens. Salvinorin A also produced dose-related dissociative effects and impairments in recall/recognition memory. At 1-month follow-up, there was no evidence of persisting adverse effects. Participants reported salvinorin A effects were qualitatively different from other drugs. Conclusions Salvinorin A produces a unique profile of subjective and cognitive effects, including strong dissociative effects and memory impairment, which only partially overlap with classic hallucinogen effects. Along with nonhuman studies of salvinorin A, these results are important for understanding the neurobiology of the kappa opioid system and may ultimately have important therapeutic applications. PMID:23135605

  20. Cannabis-related episodic memory deficits and hippocampal morphological differences in healthy individuals and schizophrenia subjects.

    PubMed

    Smith, Matthew J; Cobia, Derin J; Reilly, James L; Gilman, Jodi M; Roberts, Andrea G; Alpert, Kathryn I; Wang, Lei; Breiter, Hans C; Csernansky, John G

    2015-09-01

    Cannabis use has been associated with episodic memory (EM) impairments and abnormal hippocampus morphology among both healthy individuals and schizophrenia subjects. Considering the hippocampus' role in EM, research is needed to evaluate the relationship between cannabis-related hippocampal morphology and EM among healthy and clinical groups. We examined differences in hippocampus morphology between control and schizophrenia subjects with and without a past (not current) cannabis use disorder (CUD). Subjects group-matched on demographics included 44 healthy controls (CON), 10 subjects with a CUD history (CON-CUD), 28 schizophrenia subjects with no history of substance use disorders (SCZ), and 15 schizophrenia subjects with a CUD history (SCZ-CUD). Large-deformation, high-dimensional brain mapping with MRI produced surface-based representations of the hippocampus that were compared across all four groups and correlated with EM and CUD history. Surface maps of the hippocampus were generated to visualize morphological differences. CON-CUD and SCZ-CUD were characterized by distinct cannabis-related hippocampal shape differences and parametric deficits in EM performance. Shape differences observed in CON-CUD were associated with poorer EM performance, while shape differences observed in SCZ-CUD were associated with a longer duration of CUD and shorter duration of CUD remission. A past history of CUD may be associated with notable differences in hippocampal morphology and EM impairments among adults with and without schizophrenia. Although the results may be compatible with a causal hypothesis, we must consider that the observed cannabis-related shape differences in the hippocampus could also be explained as biomarkers of a neurobiological susceptibility to poor memory or the effects of cannabis.

  1. Catechol-O-methyltransferase (COMT) Genotype Affects Age-Related Changes in Plasticity in Working Memory: A Pilot Study

    PubMed Central

    Riemer, Thomas G.; Schulte, Stefanie; Onken, Johanna; Heinz, Andreas; Rapp, Michael A.

    2014-01-01

    Objectives. Recent work suggests that a genetic variation associated with increased dopamine metabolism in the prefrontal cortex (catechol-O-methyltransferase Val158Met; COMT) amplifies age-related changes in working memory performance. Research on younger adults indicates that the influence of dopamine-related genetic polymorphisms on working memory performance increases when testing the cognitive limits through training. To date, this has not been studied in older adults. Method. Here we investigate the effect of COMT genotype on plasticity in working memory in a sample of 14 younger (aged 24–30 years) and 25 older (aged 60–75 years) healthy adults. Participants underwent adaptive training in the n-back working memory task over 12 sessions under increasing difficulty conditions. Results. Both younger and older adults exhibited sizeable behavioral plasticity through training (P < .001), which was larger in younger as compared to older adults (P < .001). Age-related differences were qualified by an interaction with COMT genotype (P < .001), and this interaction was due to decreased behavioral plasticity in older adults carrying the Val/Val genotype, while there was no effect of genotype in younger adults. Discussion. Our findings indicate that age-related changes in plasticity in working memory are critically affected by genetic variation in prefrontal dopamine metabolism. PMID:24772423

  2. A Neural Mechanism for Surprise-related Interruptions of Visuospatial Working Memory.

    PubMed

    Wessel, Jan R

    2016-11-30

    Surprising perceptual events recruit a fronto-basal ganglia mechanism for inhibition, which suppresses motor activity following surprise. A recent study found that this inhibitory mechanism also disrupts the maintenance of verbal working memory (WM) after surprising tones. However, it is unclear whether this same mechanism also relates to surprise-related interruptions of non-verbal WM. We tested this hypothesis using a change-detection task, in which surprising tones impaired visuospatial WM. Participants also performed a stop-signal task (SST). We used independent component analysis and single-trial scalp-electroencephalogram to test whether the same inhibitory mechanism that reflects motor inhibition in the SST relates to surprise-related visuospatial WM decrements, as was the case for verbal WM. As expected, surprising tones elicited activity of the inhibitory mechanism, and this activity correlated strongly with the trial-by-trial level of surprise. However, unlike for verbal WM, the activity of this mechanism was unrelated to visuospatial WM accuracy. Instead, inhibition-independent activity that immediately succeeded the inhibitory mechanism was increased when visuospatial WM was disrupted. This shows that surprise-related interruptions of visuospatial WM are not effected by the same inhibitory mechanism that interrupts verbal WM, and instead provides evidence for a 2-stage model of distraction.

  3. RGB-NIR active gated imaging

    NASA Astrophysics Data System (ADS)

    Spooren, Nick; Geelen, Bert; Tack, Klaas; Lambrechts, Andy; Jayapala, Murali; Ginat, Ran; David, Yaara; Levi, Eyal; Grauer, Yoav

    2016-10-01

    This paper presents multispectral active gated imaging in relation to the transportation and security fields. Active gated imaging is based on a fast gated camera and pulsed illuminator, synchronized in the time domain to provide range based images. We have developed a multispectral pattern deposited on a gated CMOS Image Sensor (CIS) with a pulsed Near Infrared VCSEL module. This paper will cover the component-level description of the multispectral gated CIS including the camera and illuminator units. Furthermore, the design considerations and characterization results of the spectral filters are presented together with a newly developed image processing method.

  4. Differences in Induced Brain Activity during the Performance of Learning and Working-Memory Tasks Related to Intelligence

    ERIC Educational Resources Information Center

    Jausovec, Norbert; Jausovec, Ksenija

    2004-01-01

    Thirteen high intelligent (H-IQ) and 13 low intelligent (L-IQ) individuals solved two figural working-memory (WM) tasks and two figural learning tasks while their EEG was recorded. For the WM tasks, only in the theta band group related differences in induced event-related desynchronization/synchronization (ERD/ERS) were observed. L-IQ individuals…

  5. When Does Memory Monitoring Succeed versus Fail? Comparing Item-Specific and Relational Encoding in the DRM Paradigm

    ERIC Educational Resources Information Center

    Huff, Mark J.; Bodner, Glen E.

    2013-01-01

    We compared the effects of item-specific versus relational encoding on recognition memory in the Deese-Roediger-McDermott paradigm. In Experiment 1, we directly compared item-specific and relational encoding instructions, whereas in Experiments 2 and 3 we biased pleasantness and generation tasks, respectively, toward one or the other type of…

  6. Distributed multiport memory architecture

    NASA Technical Reports Server (NTRS)

    Kohl, W. H. (Inventor)

    1983-01-01

    A multiport memory architecture is diclosed for each of a plurality of task centers connected to a command and data bus. Each task center, includes a memory and a plurality of devices which request direct memory access as needed. The memory includes an internal data bus and an internal address bus to which the devices are connected, and direct timing and control logic comprised of a 10-state ring counter for allocating memory devices by enabling AND gates connected to the request signal lines of the devices. The outputs of AND gates connected to the same device are combined by OR gates to form an acknowledgement signal that enables the devices to address the memory during the next clock period. The length of the ring counter may be effectively lengthened to any multiple of ten to allow for more direct memory access intervals in one repetitive sequence. One device is a network bus adapter which serially shifts onto the command and data bus, a data word (8 bits plus control and parity bits) during the next ten direct memory access intervals after it has been granted access. The NBA is therefore allocated only one access in every ten intervals, which is a predetermined interval for all centers. The ring counters of all centers are periodically synchronized by DMA SYNC signal to assure that all NBAs be able to function in synchronism for data transfer from one center to another.

  7. Age-related decline in verbal learning is moderated by demographic factors, working memory capacity, and presence of amnestic mild cognitive impairment.

    PubMed

    Constantinidou, Fofi; Zaganas, Ioannis; Papastefanakis, Emmanouil; Kasselimis, Dimitrios; Nidos, Andreas; Simos, Panagiotis G

    2014-09-01

    Age-related memory changes are highly varied and heterogeneous. The study examined the rate of decline in verbal episodic memory as a function of education level, auditory attention span and verbal working memory capacity, and diagnosis of amnestic mild cognitive impairment (a-MCI). Data were available on a community sample of 653 adults aged 17-86 years and 70 patients with a-MCI recruited from eight broad geographic areas in Greece and Cyprus. Measures of auditory attention span and working memory capacity (digits forward and backward) and verbal episodic memory (Auditory Verbal Learning Test [AVLT]) were used. Moderated mediation regressions on data from the community sample did not reveal significant effects of education level on the rate of age-related decline in AVLT indices. The presence of a-MCI was a significant moderator of the direct effect of Age on both immediate and delayed episodic memory indices. The rate of age-related decline in verbal episodic memory is normally mediated by working memory capacity. Moreover, in persons who display poor episodic memory capacity (a-MCI group), age-related memory decline is expected to advance more rapidly for those who also display relatively poor verbal working memory capacity.

  8. Individual differences in components of reaction time distributions and their relations to working memory and intelligence.

    PubMed

    Schmiedek, Florian; Oberauer, Klaus; Wilhelm, Oliver; Süss, Heinz-Martin; Wittmann, Werner W

    2007-08-01

    The authors bring together approaches from cognitive and individual differences psychology to model characteristics of reaction time distributions beyond measures of central tendency. Ex-Gaussian distributions and a diffusion model approach are used to describe individuals' reaction time data. The authors identified common latent factors for each of the 3 ex-Gaussian parameters and for 3 parameters central to the diffusion model using structural equation modeling for a battery of choice reaction tasks. These factors had differential relations to criterion constructs. Parameters reflecting the tail of the distribution (i.e., tau in the ex-Gaussian and drift rate in the diffusion model) were the strongest unique predictors of working memory, reasoning, and psychometric speed. Theories of controlled attention and binding are discussed as potential theoretical explanations.

  9. The relation between receptive grammar and procedural, declarative, and working memory in specific language impairment

    PubMed Central

    Conti-Ramsden, Gina; Ullman, Michael T.; Lum, Jarrad A. G.

    2015-01-01

    What memory systems underlie grammar in children, and do these differ between typically developing (TD) children and children with specific language impairment (SLI)? Whilst there is substantial evidence linking certain memory deficits to the language problems in children with SLI, few studies have investigated multiple memory systems simultaneously, examining not only possible memory deficits but also memory abilities that may play a compensatory role. This study examined the extent to which procedural, declarative, and working memory abilities predict receptive grammar in 45 primary school aged children with SLI (30 males, 15 females) and 46 TD children (30 males, 16 females), both on average 9;10 years of age. Regression analyses probed measures of all three memory systems simultaneously as potential predictors of receptive grammar. The model was significant, explaining 51.6% of the variance. There was a significant main effect of learning in procedural memory and a significant group × procedural learning interaction. Further investigation of the interaction revealed that procedural learning predicted grammar in TD but not in children with SLI. Indeed, procedural learning was the only predictor of grammar in TD. In contrast, only learning in declarative memory significantly predicted grammar in SLI. Thus, different memory systems are associated with receptive grammar abilities in children with SLI and their TD peers. This study is, to our knowledge, the first to demonstrate a significant group by memory system interaction in predicting grammar in children with SLI and their TD peers. In line with Ullman’s Declarative/Procedural model of language and procedural deficit hypothesis of SLI, variability in understanding sentences of varying grammatical complexity appears to be associated with variability in procedural memory abilities in TD children, but with declarative memory, as an apparent compensatory mechanism, in children with SLI. PMID:26284013

  10. The relation between receptive grammar and procedural, declarative, and working memory in specific language impairment.

    PubMed

    Conti-Ramsden, Gina; Ullman, Michael T; Lum, Jarrad A G

    2015-01-01

    What memory systems underlie grammar in children, and do these differ between typically developing (TD) children and children with specific language impairment (SLI)? Whilst there is substantial evidence linking certain memory deficits to the language problems in children with SLI, few studies have investigated multiple memory systems simultaneously, examining not only possible memory deficits but also memory abilities that may play a compensatory role. This study examined the extent to which procedural, declarative, and working memory abilities predict receptive grammar in 45 primary school aged children with SLI (30 males, 15 females) and 46 TD children (30 males, 16 females), both on average 9;10 years of age. Regression analyses probed measures of all three memory systems simultaneously as potential predictors of receptive grammar. The model was significant, explaining 51.6% of the variance. There was a significant main effect of learning in procedural memory and a significant group × procedural learning interaction. Further investigation of the interaction revealed that procedural learning predicted grammar in TD but not in children with SLI. Indeed, procedural learning was the only predictor of grammar in TD. In contrast, only learning in declarative memory significantly predicted grammar in SLI. Thus, different memory systems are associated with receptive grammar abilities in children with SLI and their TD peers. This study is, to our knowledge, the first to demonstrate a significant group by memory system interaction in predicting grammar in children with SLI and their TD peers. In line with Ullman's Declarative/Procedural model of language and procedural deficit hypothesis of SLI, variability in understanding sentences of varying grammatical complexity appears to be associated with variability in procedural memory abilities in TD children, but with declarative memory, as an apparent compensatory mechanism, in children with SLI.

  11. Complexin2 modulates working memory-related neural activity in patients with schizophrenia.

    PubMed

    Hass, Johanna; Walton, Esther; Kirsten, Holger; Turner, Jessica; Wolthusen, Rick; Roessner, Veit; Sponheim, Scott R; Holt, Daphne; Gollub, Randy; Calhoun, Vince D; Ehrlich, Stefan

    2015-03-01

    The specific contribution of risk or candidate gene variants to the complex phenotype of schizophrenia is largely unknown. Studying the effects of such variants on brain function can provide insight into disease-associated mechanisms on a neural systems level. Previous studies found common variants in the complexin2 (CPLX2) gene to be highly associated with cognitive dysfunction in schizophrenia patients. Similarly, cognitive functioning was found to be impaired in Cplx2 gene-deficient mice if they were subjected to maternal deprivation or mild brain trauma during puberty. Here, we aimed to study seven common CPLX2 single-nucleotide polymorphisms (SNPs) and their neurogenetic risk mechanisms by investigating their relationship to a schizophrenia-related functional neuroimaging intermediate phenotype. We examined functional MRI and genotype data collected from 104 patients with DSM-IV-diagnosed schizophrenia and 122 healthy controls who participated in the Mind Clinical Imaging Consortium study of schizophrenia. Seven SNPs distributed over the whole CPLX2 gene were tested for association with working memory-elicited neural activity in a frontoparietal neural network. Three CPLX2 SNPs were significantly associated with increased neural activity in the dorsolateral prefrontal cortex and intraparietal sulcus in the schizophrenia sample, but showed no association in healthy controls. Since increased working memory-related neural activity in individuals with or at risk for schizophrenia has been interpreted as 'neural inefficiency,' these findings suggest that certain variants of CPLX2 may contribute to impaired brain function in schizophrenia, possibly combined with other deleterious genetic variants, adverse environmental events, or developmental insults.

  12. Complexin2 modulates working memory-related neural activity in patients with schizophrenia

    SciTech Connect

    Hass, Johanna; Walton, Esther; Kirsten, Holger; Turner, Jessica; Wolthusen, Rick; Roessner, Veit; Sponheim, Scott R.; Holt, Daphne; Gollub, Randy; Calhoun, Vince D.; Ehrlich, Stefan

    2014-10-09

    The specific contribution of risk or candidate gene variants to the complex phenotype of schizophrenia is largely unknown. Studying the effects of such variants on brain function can provide insight into disease-associated mechanisms on a neural systems level. Previous studies found common variants in the complexin2 (CPLX2) gene to be highly associated with cognitive dysfunction in schizophrenia patients. Similarly, cognitive functioning was found to be impaired in Cplx2 gene-deficient mice if they were subjected to maternal deprivation or mild brain trauma during puberty. Here, we aimed to study seven common CPLX2 single-nucleotide polymorphisms (SNPs) and their neurogenetic risk mechanisms by investigating their relationship to a schizophrenia-related functional neuroimaging intermediate phenotype. In this paper, we examined functional MRI and genotype data collected from 104 patients with DSM-IV-diagnosed schizophrenia and 122 healthy controls who participated in the Mind Clinical Imaging Consortium study of schizophrenia. Seven SNPs distributed over the whole CPLX2 gene were tested for association with working memory-elicited neural activity in a frontoparietal neural network. Three CPLX2 SNPs were significantly associated with increased neural activity in the dorsolateral prefrontal cortex and intraparietal sulcus in the schizophrenia sample, but showed no association in healthy controls. Finally, since increased working memory-related neural activity in individuals with or at risk for schizophrenia has been interpreted as ‘neural inefficiency,’ these findings suggest that certain variants of CPLX2 may contribute to impaired brain function in schizophrenia, possibly combined with other deleterious genetic variants, adverse environmental events, or developmental insults.

  13. Complexin2 modulates working memory-related neural activity in patients with schizophrenia

    DOE PAGES

    Hass, Johanna; Walton, Esther; Kirsten, Holger; ...

    2014-10-09

    The specific contribution of risk or candidate gene variants to the complex phenotype of schizophrenia is largely unknown. Studying the effects of such variants on brain function can provide insight into disease-associated mechanisms on a neural systems level. Previous studies found common variants in the complexin2 (CPLX2) gene to be highly associated with cognitive dysfunction in schizophrenia patients. Similarly, cognitive functioning was found to be impaired in Cplx2 gene-deficient mice if they were subjected to maternal deprivation or mild brain trauma during puberty. Here, we aimed to study seven common CPLX2 single-nucleotide polymorphisms (SNPs) and their neurogenetic risk mechanisms bymore » investigating their relationship to a schizophrenia-related functional neuroimaging intermediate phenotype. In this paper, we examined functional MRI and genotype data collected from 104 patients with DSM-IV-diagnosed schizophrenia and 122 healthy controls who participated in the Mind Clinical Imaging Consortium study of schizophrenia. Seven SNPs distributed over the whole CPLX2 gene were tested for association with working memory-elicited neural activity in a frontoparietal neural network. Three CPLX2 SNPs were significantly associated with increased neural activity in the dorsolateral prefrontal cortex and intraparietal sulcus in the schizophrenia sample, but showed no association in healthy controls. Finally, since increased working memory-related neural activity in individuals with or at risk for schizophrenia has been interpreted as ‘neural inefficiency,’ these findings suggest that certain variants of CPLX2 may contribute to impaired brain function in schizophrenia, possibly combined with other deleterious genetic variants, adverse environmental events, or developmental insults.« less

  14. Event-related brain potentials that distinguish false memory for events that occurred only seconds in the past

    PubMed Central

    2012-01-01

    Background False memory often involves retrieving events from the distant past that did not actually happen. However, recent evidence obtained using the Deese/Roediger-McDermott (DRM) paradigm for eliciting false memory experiences suggests that individuals can falsely believe that events occurred mere seconds in the past when they in fact did not. Subjects in these experiments endorsed unstudied critical lure words as having been studied, despite the fact that word lists were studied just moments before. We identified event-related brain potential (ERP) correlates of this experience, and included a repetition priming manipulation to better assess the functional significance of these ERPs. Methods Behavioral and ERP data were collected from 21 Capital Normal University students using a short-term DRM task. Results Two categories of effects were identified that distinguished true from false short-term memory: (1) early semantic priming effects from 300 to 500 ms and (2) later retrieval and retrieval-monitoring effects after 500 ms. The repetition priming manipulation had distinct influences on these effects, consistent with their differential associations with semantic priming versus episodic retrieval. Conclusion Characterization of ERPs related to semantic priming and episodic retrieval provides important information regarding the mechanisms of short-term false memory. In contrast, most studies examining false memory in standard long-delay DRM paradigms identify ERP effects related only to retrieval monitoring. These findings highlight the neural processing involved in illusions of memory after very brief delays and highlight the role of semantic processing in short-term false memory. PMID:22846189

  15. Improvement in memory and static balance with abstinence in alcoholic men and women: selective relations with change in brain structure.

    PubMed

    Rosenbloom, Margaret J; Rohlfing, Torsten; O'Reilly, Anne W; Sassoon, Stephanie A; Pfefferbaum, Adolf; Sullivan, Edith V

    2007-07-15

    We investigated whether changes in memory or static balance in chronic alcoholics, occurring with abstinence or relapse, are associated with changes in lateral and fourth ventricular volume. Alcoholics meeting DSM-IV criteria for Alcohol Dependence (n=15) and non-alcoholic controls (n=26) were examined twice at a mean interval of 2 years with standard Wechsler Abbreviated Scale of Intelligence (WASI), Wechsler Memory Scale-Revised (WMS-R) tests, an ataxia battery, and structural MRI. At study entry, alcoholics had been abstinent on average for over 4 months and achieved lower scores than controls on WASI General IQ Index, WMS-R General Memory Index, and the ataxia battery. The 10 alcoholics who maintained sobriety at retest did not differ at study entry in socio-demographic measures, alcohol use, or WASI and WMS-R summary scores from the five relapsers. At follow-up, abstainers improved more than controls on the WMS-R General Memory Index. Ataxia tended to improve in abstainers relative to controls. Associations were observed between memory and lateral ventricular volume change and between ataxia and fourth ventricular volume change in alcoholics but not in the controls. Both memory and ataxia can improve with sustained sobriety, and brain-behavior associations suggest selective brain structural substrates for the changes observed.

  16. Detail view of stone entrance gate pylon showing carved site ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Detail view of stone entrance gate pylon showing carved site name and Great Seal of the United States. View looking northeast. - Flanders Field American Cemetery & Memorial, Wortegemseweg 117, Waregem, West Flanders (Belgium)

  17. The Inaugural Elijah B. Saunders Memorial Lecture: The Global Consequences of Hypertension and Related Disparities

    PubMed Central

    Mensah, George A.

    2016-01-01

    This inaugural memorial lecture provides an opportunity to celebrate the life of Elijah B. Saunders, MD, FACC and pays tribute to his pioneering spirit in the quest to advance health equity in the prevention and control of hypertension and cardiovascular diseases. It also enables an assessment of the state of the global burden of hypertension and related disparities. Despite the remarkable biomedical research progress made over the last half-century, hypertension remains the leading risk factor for global disease burden and the major preventable contributor to cardiovascular and all-cause mortality. Additionally, disparities in hypertension-related morbidity and mortality remain pervasive worldwide. National hypertension control rates showing progress often mask important suboptimal treatment and control in population groups defined by sex, race, ethnicity, geography, and social and environmental determinants. Within these groups, many hypertension-related disparities remain largely unchanged while other gaps have widened. In essence, current research has been relatively ineffective in guiding large-scale, sustained elimination of hypertension-related disparities. An important explanation for these observations may be the significant advances made in observational epidemiological research, especially in improved surveillance and data collection that document the extent of disparities in marked contrast to the relative paucity of interventional disparities research. The paucity of these interventional research studies remains a continuing challenge. The time has come for renewed efforts in building strategic partnerships that leverage transdisciplinary, multi-sectoral expertise to provide global leadership in interventional implementation research for hypertension control and elimination of related disparities. Developing an appropriately skilled implementation research workforce will be crucial. The National Heart, Lung, and Blood Institute and its biomedical

  18. Extraversion and short-term memory for chromatic stimuli: an event-related potential analysis.

    PubMed

    Stauffer, Corinne C; Indermühle, Rebekka; Troche, Stefan J; Rammsayer, Thomas H

    2012-10-01

    The present study investigated extraversion-related individual differences in visual short-term memory (VSTM) functioning. Event related potentials were recorded from 50 introverts and 50 extraverts while they performed a VSTM task based on a color-change detection paradigm with three different set sizes. Although introverts and extraverts showed almost identical hit rates and reaction times, introverts displayed larger N1 amplitudes than extraverts independent of color change or set size. Extraverts also showed larger P3 amplitudes compared to introverts when there was a color change, whereas no extraversion-related difference in P3 amplitude was found in the no-change condition. Our findings provided the first experimental evidence that introverts' greater reactivity to punctuate physical stimulation, as indicated by larger N1 amplitude, also holds for complex visual stimulus patterns. Furthermore, P3 amplitude in the change condition was larger for extraverts than introverts suggesting higher sensitivity to context change. Finally, there were no extraversion-related differences in P3 amplitude dependent on set size. This latter finding does not support the resource allocation explanation as a source of differences between introverts and extraverts.

  19. Resveratrol prevents age-related memory and mood dysfunction with increased hippocampal neurogenesis and microvasculature, and reduced glial activation.

    PubMed

    Kodali, Maheedhar; Parihar, Vipan K; Hattiangady, Bharathi; Mishra, Vikas; Shuai, Bing; Shetty, Ashok K

    2015-01-28

    Greatly waned neurogenesis, diminished microvasculature, astrocyte hypertrophy and activated microglia are among the most conspicuous structural changes in the aged hippocampus. Because these alterations can contribute to age-related memory and mood impairments, strategies efficacious for mitigating these changes may preserve cognitive and mood function in old age. Resveratrol, a phytoalexin found in the skin of red grapes having angiogenic and antiinflammatory properties, appears ideal for easing these age-related changes. Hence, we examined the efficacy of resveratrol for counteracting age-related memory and mood impairments and the associated detrimental changes in the hippocampus. Two groups of male F344 rats in late middle-age having similar learning and memory abilities were chosen and treated with resveratrol or vehicle for four weeks. Analyses at ~25 months of age uncovered improved learning, memory and mood function in resveratrol-treated animals but impairments in vehicle-treated animals. Resveratrol-treated animals also displayed increased net neurogenesis and microvasculature, and diminished astrocyte hypertrophy and microglial activation in the hippocampus. These results provide novel evidence that resveratrol treatment in late middle age is efficacious for improving memory and mood function in old age. Modulation of the hippocampus plasticity and suppression of chronic low-level inflammation appear to underlie the functional benefits mediated by resveratrol.

  20. Do emotional stimuli enhance or impede recall relative to neutral stimuli? An investigation of two "false memory" tasks.

    PubMed

    Monds, Lauren A; Paterson, Helen M; Kemp, Richard I

    2016-10-06

    Many eyewitness memory situations involve negative and distressing events; however, many studies investigating "false memory" phenomena use neutral stimuli only. The aim of the present study was to determine how both the Deese-Roediger-McDermott (DRM) procedure and the Misinformation Effect Paradigm tasks were related to each other using distressing and neutral stimuli. Participants completed the DRM (with negative and neutral word lists) and viewed a distressing or neutral film. Misinformation for the film was introduced and memory was assessed. Film accuracy and misinformation susceptibility were found to be greater for those who viewed the distressing film relative to the neutral film. Accuracy responses on both tasks were related, however, susceptibility to the DRM illusion and Misinformation Effect were not. The misinformation findings support the Paradoxical Negative Emotion (PNE) hypothesis that negative stimuli will lead to remembering more accurate details but also greater likelihood of memory distortion. However, the PNE hypothesis was not supported for the DRM results. The findings also suggest that the DRM and Misinformation tasks are not equivalent and may have differences in underlying mechanisms. Future research should focus on more ecologically valid methods of assessing false memory.

  1. Elucidating the neural correlates of related false memories using a systematic measure of perceptual relatedness.

    PubMed

    Turney, Indira C; Dennis, Nancy A

    2017-02-01

    Previous memory research has exploited the perceptual similarities between lures and targets in order to evoke false memories. Nevertheless, while some studies have attempted to use lures that are objectively more similar than others, no study has systematically controlled for perceptual overlap between target and lure items and its role in accounting for false alarm rates or the neural processes underlying such perceptual false memories. The current study looked to fill this gap in the literature by using a face-morphing program to systematically control for the amount of perceptual overlap between lures and targets. Our results converge with previous studies in finding a pattern of differences between true and false memories. Most importantly, expanding upon this work, parametric analyses showed false memory activity increases with respect to the similarity between lures and targets within bilateral middle temporal gyri and right medial prefrontal cortex (mPFC). Moreover, this pattern of activation was unique to false memories and could not be accounted for by relatedness alone. Connectivity analyses further find that activity in the mPFC and left middle temporal gyrus co-vary, suggestive of gist-based monitoring within the context of false memories. Interestingly, neither the MTL nor the fusiform face area exhibited modulation as a function of target-lure relatedness. Overall, these results provide insight into the processes underlying false memories and further enhance our understanding of the role perceptual similarity plays in supporting false memories.

  2. Newly-formed emotional memories guide selective attention processes: Evidence from event-related potentials

    PubMed Central

    Schupp, Harald T.; Kirmse, Ursula; Schmälzle, Ralf; Flaisch, Tobias; Renner, Britta

    2016-01-01

    Emotional cues can guide selective attention processes. However, emotional stimuli can both activate long-term memory representations reflecting general world knowledge and engage newly formed memory representations representing specific knowledge from the immediate past. Here, the self-completion feature of associative memory was utilized to assess the regulation of attention processes by newly-formed emotional memory. First, new memory representations were formed by presenting pictures depicting a person either in an erotic pose or as a portrait. Afterwards, to activate newly-built memory traces, edited pictures were presented showing only the head region of the person. ERP recordings revealed the emotional regulation of attention by newly-formed memories. Specifically, edited pictures from the erotic compared to the portrait category elicited an early posterior negativity and late positive potential, similar to the findings observed for the original pictures. A control condition showed that the effect was dependent on newly-formed memory traces. Given the large number of new memories formed each day, they presumably make an important contribution to the regulation of attention in everyday life. PMID:27321471

  3. Memory Dysfunction

    PubMed Central

    Matthews, Brandy R.

    2015-01-01

    Purpose of Review: This article highlights the dissociable human memory systems of episodic, semantic, and procedural memory in the context of neurologic illnesses known to adversely affect specific neuroanatomic structures relevant to each memory system. Recent Findings: Advances in functional neuroimaging and refinement of neuropsychological and bedside assessment tools continue to support a model of multiple memory systems that are distinct yet complementary and to support the potential for one system to be engaged as a compensatory strategy when a counterpart system fails. Summary: Episodic memory, the ability to recall personal episodes, is the subtype of memory most often perceived as dysfunctional by patients and informants. Medial temporal lobe structures, especially the hippocampal formation and associated cortical and subcortical structures, are most often associated with episodic memory loss. Episodic memory dysfunction may present acutely, as in concussion; transiently, as in transient global amnesia (TGA); subacutely, as in thiamine deficiency; or chronically, as in Alzheimer disease. Semantic memory refers to acquired knowledge about the world. Anterior and inferior temporal lobe structures are most often associated with semantic memory loss. The semantic variant of primary progressive aphasia (svPPA) is the paradigmatic disorder resulting in predominant semantic memory dysfunction. Working memory, associated with frontal lobe function, is the active maintenance of information in the mind that can be potentially manipulated to complete goal-directed tasks. Procedural memory, the ability to learn skills that become automatic, involves the basal ganglia, cerebellum, and supplementary motor cortex. Parkinson disease and related disorders result in procedural memory deficits. Most memory concerns warrant bedside cognitive or neuropsychological evaluation and neuroimaging to assess for specific neuropathologies and guide treatment. PMID:26039844

  4. How experience shapes memory for faces: an event-related potential study on the own-age bias.

    PubMed

    Wiese, Holger; Wolff, Nicole; Steffens, Melanie C; Schweinberger, Stefan R

    2013-10-01

    Young adults more accurately remember own-age than older faces. We tested whether this own-age bias (OAB) is reduced by increased experience. Young experts (geriatric nurses) and controls performed a recognition experiment with young and old faces. Critically, while control participants demonstrated better memory for young faces, no OAB was observed in the experts. Event-related potentials revealed larger N170 and P2 amplitudes for young than old faces in both groups, suggesting no group differences during early perceptual processing. At test, N250 repetition effects were more anteriorily distributed for own- than other-age faces in control participants, whereas experts showed no corresponding effects. A larger late positive component (LPC) for old than young faces was observed in controls, but not in experts. Larger LPCs may reflect prolonged stimulus processing compromising memory retrieval. In sum, experience with other-age faces does not affect early perceptual processing, but modulates later stages related to memory retrieval.

  5. Novel Technologies for Next Generation Memory

    DTIC Science & Technology

    2013-07-25

    Schematic cross-sectional view and TEM image of a typical independently-Controlled- Double- Gate Floating -Body-Cell device... floating gate 12 1 .15 Example of mechanical switch memory in dai ly l i fe 14 1.16 Illustration of micro-electro...transistors, the two gates in double- gate DRAM cells are not electrically connected. This structure permits an electrically induced floating body to

  6. 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.

  7. The Impact of NMDA Receptor Blockade on Human Working Memory-Related Prefrontal Function and Connectivity

    PubMed Central

    Driesen, Naomi R; McCarthy, Gregory; Bhagwagar, Zubin; Bloch, Michael H; Calhoun, Vincent D; D'Souza, Deepak C; Gueorguieva, Ralitza; He, George; Leung, Hoi-Chung; Ramani, Ramachandran; Anticevic, Alan; Suckow, Raymond F; Morgan, Peter T; Krystal, John H

    2013-01-01

    Preclinical research suggests that N-methyl-D-aspartate glutamate receptors (NMDA-Rs) have a crucial role in working memory (WM). In this study, we investigated the role of NMDA-Rs in the brain activation and connectivity that subserve WM. Because of its importance in WM, the lateral prefrontal cortex, particularly the dorsolateral prefrontal cortex and its connections, were the focus of analyses. Healthy participants (n=22) participated in a single functional magnetic resonance imaging session. They received saline and then the NMDA-R antagonist ketamine while performing a spatial WM task. Time-course analysis was used to compare lateral prefrontal activation during saline and ketamine administration. Seed-based functional connectivity analysis was used to compare dorsolateral prefrontal connectivity during the two conditions and global-based connectivity was used to test for laterality in these effects. Ketamine reduced accuracy on the spatial WM task and brain activation during the encoding and early maintenance (EEM) period of task trials. Decrements in task-related activation during EEM were related to performance deficits. Ketamine reduced connectivity in the DPFC network bilaterally, and region-specific reductions in connectivity were related to performance. These results support the hypothesis that NMDA-Rs are critical for WM. The knowledge gained may be helpful in understanding disorders that might involve glutamatergic deficits such as schizophrenia and developing better treatments. PMID:23856634

  8. The impact of NMDA receptor blockade on human working memory-related prefrontal function and connectivity.

    PubMed

    Driesen, Naomi R; McCarthy, Gregory; Bhagwagar, Zubin; Bloch, Michael H; Calhoun, Vincent D; D'Souza, Deepak C; Gueorguieva, Ralitza; He, George; Leung, Hoi-Chung; Ramani, Ramachandran; Anticevic, Alan; Suckow, Raymond F; Morgan, Peter T; Krystal, John H

    2013-12-01

    Preclinical research suggests that N-methyl-D-aspartate glutamate receptors (NMDA-Rs) have a crucial role in working memory (WM). In this study, we investigated the role of NMDA-Rs in the brain activation and connectivity that subserve WM. Because of its importance in WM, the lateral prefrontal cortex, particularly the dorsolateral prefrontal cortex and its connections, were the focus of analyses. Healthy participants (n=22) participated in a single functional magnetic resonance imaging session. They received saline and then the NMDA-R antagonist ketamine while performing a spatial WM task. Time-course analysis was used to compare lateral prefrontal activation during saline and ketamine administration. Seed-based functional connectivity analysis was used to compare dorsolateral prefrontal connectivity during the two conditions and global-based connectivity was used to test for laterality in these effects. Ketamine reduced accuracy on the spatial WM task and brain activation during the encoding and early maintenance (EEM) period of task trials. Decrements in task-related activation during EEM were related to performance deficits. Ketamine reduced connectivity in the DPFC network bilaterally, and region-specific reductions in connectivity were related to performance. These results support the hypothesis that NMDA-Rs are critical for WM. The knowledge gained may be helpful in understanding disorders that might involve glutamatergic deficits such as schizophrenia and developing better treatments.

  9. Working memory-related frontal theta activity is decreased under acute stress.

    PubMed

    Gärtner, Matti; Rohde-Liebenau, Lea; Grimm, Simone; Bajbouj, Malek

    2014-05-01

    Acute stress impairs prefrontal cortex (PFC) function and has detrimental effects on working memory (WM) performance. Converging evidence from electrophysiological studies suggests a close link between WM processes and frontal theta (FT) activity (4-8 Hz). However, the effect of stress on WM-related FT activity has not been investigated yet. To shed light on this topic we acquired EEG data from 31 healthy male subjects who underwent a stressful and a neutral control condition. In both conditions, they performed an n-back WM task at two different difficulty levels. Our results showed that WM-related FT activity was decreased under stress. Behaviorally, we found performance impairments under stress in the difficult task condition that were related to FT decreases. Increased cortisol levels indicated a successful moderate stress induction. These findings indicate that FT is a potential neurobiological marker for intact PFC functioning during WM and further supports the recently made assumption that FT acts in the PFC to optimize performance.

  10. Event-related theta oscillations during working memory tasks in patients with schizophrenia and healthy controls.

    PubMed

    Schmiedt, C; Brand, A; Hildebrandt, H; Basar-Eroglu, C

    2005-12-01

    Altered frontal lobe activity and executive control associated with working memory (WM) dysfunction are recognized as core deficits in schizophrenia. These impairments have been discussed as being associated with deficits in self-regulated action monitoring and anticipatory action plan generation. To study electrophysiological correlates of executive control -- specifically action monitoring and action rule switching -- under varying WM load, we used a paradigm derived from classic N-back (WM) tasks and requiring monitoring of simple actions. We focused on event-related changes in post-stimulus theta oscillatory activity during varying cognitive and WM demand in healthy controls and schizophrenia patients. The results show significant WM load and rule-switching-related increases of post-stimulus theta amplitude at fronto-central locations in controls. In patients with schizophrenia, there was no such modulation, but -- apart from an increased early theta at left temporal locations -- generally reduced late theta responses in all tasks and at all locations. Furthermore, the patients with schizophrenia showed significant differences in their error patterns, which imply differences in automation and anticipation of actions between controls and patients. These findings suggest that theta oscillations are involved in mediating frontal lobe activity and functions related to enhanced executive control. We conclude that the patients with schizophrenia showed deficits in acquiring a mental task set which appear to be associated with impairments in action monitoring and task-specific regulation of executive control.

  11. Adaptive memory: the survival scenario enhances item-specific processing relative to a moving scenario.

    PubMed

    Burns, Daniel J; Hart, Joshua; Griffith, Samantha E; Burns, Amy D

    2013-01-01

    Nairne, Thompson, and Pandeirada (2007) found that retention of words rated for their relevance to survival is superior to that of words encoded under numerous other deep processing conditions. They suggested that our memory systems might have evolved to confer an advantage for survival-relevant information. Burns, Burns, and Hwang (2011) suggested a two-process explanation of the proximate mechanisms responsible for the survival advantage. Whereas most control tasks encourage only one type of processing, the survival task encourages both item-specific and relational processing. They found that when control tasks encouraged both types of processing, the survival processing advantage was eliminated. However, none of their control conditions included non-survival scenarios (e.g., moving, vacation, etc.), so it is not clear how this two-process explanation would explain the survival advantage when scenarios are used as control conditions. The present experiments replicated the finding that the survival scenario improves recall relative to a moving scenario in both a between-lists and within-list design and also provided evidence that this difference was accompanied by an item-specific processing difference, not a difference in relational processing. The implications of these results for several existing accounts of the survival processing effect are discussed.

  12. Age-related homeostatic mid-channel proteolysis of neuronal L-type voltage-gated Ca2+ channels

    PubMed Central

    Michailidis, Ioannis E.; Abele-Henckels, Kathryn; Zhang, Wei K.; Lin, Bochao; Yu, Yong; Geyman, Larry; Ehlers, Michael D.; Pnevmatikakis, Eftychios A.; Yang, Jian

    2014-01-01

    SUMMARY Neural circuitry and brain activity depend critically on proper function of voltage-gated calcium channels (VGCCs), whose activity must be tightly controlled. We show that the main body of the pore-forming α1 subunit of neuronal L-type VGCCs, Cav1.2, is proteolytically cleaved, resulting in Cav1.2 fragment-channels that separate but remain on the plasma membrane. This “gmid-channel” proteolysis is regulated by channel activity, involves the Ca2+-dependent protease calpain and the ubiquitin-proteasome system, and causes attenuation and biophysical alterations of VGCC currents. Recombinant Cav1.2 fragment-channels mimicking the products of mid-channel proteolysis do not form active channels on their own, but when properly paired, produce currents with distinct biophysical properties. Mid-channel proteolysis increases dramatically with age and can be attenuated with an L-type VGCC blocker in vivo. Mid-channel proteolysis represents a novel form of homeostatic negative-feedback processing of VGCCs that could profoundly affect neuronal excitability, neurotransmission, neuroprotection, and calcium signaling in physiological and disease states. PMID:24908485

  13. Characteristics Of Ferroelectric Logic Gates Using a Spice-Based Model

    NASA Technical Reports Server (NTRS)

    MacLeod, Todd C.; Phillips, Thomas A.; Ho, Fat D.

    2005-01-01

    A SPICE-based model of an n-channel ferroelectric field effect transistor has been developed based on both theoretical and empirical data. This model was used to generate the I-V characteristic of several logic gates. The use of ferroelectric field effect transistors in memory circuits is being developed by several organizations. The use of FFETs in other circuits, both analog and digital needs to be better understood. The ability of FFETs to have different characteristics depending on the initial polarization can be used to create logic gates. These gates can have properties not available to standard CMOS logic gates, such as memory, reconfigurability and memory. This paper investigates basic properties of FFET logic gates. It models FFET inverter, NAND gate and multi-input NAND gate. The I-V characteristics of the gates are presented as well as transfer characteristics and timing. The model used is