Local Visual Processing in High Obsessive Compulsive Disorder (OCD) Scorers.

<p>Reaction times for big and small letters (global and local levels) were compared and examined to see whether differences would occur between a low scoring and high scoring Obsessive- Compulsive Disorder (OCD) group. OCD patients have been shown to notice and pay more attention to small details (local bias) compared to most other populations (Shapiro, 1965; Yovel et al. 2006; Caberea et al., 2001). Although there is research supporting a local bias in OCD patients, it is unclear whether the bias occurs in the early stages of visual processing or in a later memory stage (Moritz & Wendt, 2006; Hermans et al, 2008). The study specifically examined a potential local bias for high OCD scorers in the early visual stage by manipulating perceptual and attentional mechanisms in two hierarchical letter tasks (Navon, 1977; Miller, 1981a, Plaisted et al. 1999). In Experiment 1, participants were told which level (the big or small letter) to respond to, results showed that high OCD scorers responded faster to local letters, showing support for a local processing advantage. Conversely, the low OCD group responded quicker to the global level. The finding of a local advantage in Experiment 1 suggests that the local advantage may be due to perceptual mechanisms as attention was already directed to the relevant level. However, in Experiment 2 where attention was not directed and the image quality was manipulated, local and global advantage effects were not replicated for the high and low OCD groups respectively. This showed that attentional and perceptual mechanisms did not make one level easier to process over the other. Therefore, it is possible that any local bias for OCD patients occurs in a later processing stage.</p>

Local Visual Processing in High Obsessive Compulsive Disorder (OCD) Scorers.

<p>Reaction times for big and small letters (global and local levels) were compared and examined to see whether differences would occur between a low scoring and high scoring Obsessive- Compulsive Disorder (OCD) group. OCD patients have been shown to notice and pay more attention to small details (local bias) compared to most other populations (Shapiro, 1965; Yovel et al. 2006; Caberea et al., 2001). Although there is research supporting a local bias in OCD patients, it is unclear whether the bias occurs in the early stages of visual processing or in a later memory stage (Moritz & Wendt, 2006; Hermans et al, 2008). The study specifically examined a potential local bias for high OCD scorers in the early visual stage by manipulating perceptual and attentional mechanisms in two hierarchical letter tasks (Navon, 1977; Miller, 1981a, Plaisted et al. 1999). In Experiment 1, participants were told which level (the big or small letter) to respond to, results showed that high OCD scorers responded faster to local letters, showing support for a local processing advantage. Conversely, the low OCD group responded quicker to the global level. The finding of a local advantage in Experiment 1 suggests that the local advantage may be due to perceptual mechanisms as attention was already directed to the relevant level. However, in Experiment 2 where attention was not directed and the image quality was manipulated, local and global advantage effects were not replicated for the high and low OCD groups respectively. This showed that attentional and perceptual mechanisms did not make one level easier to process over the other. Therefore, it is possible that any local bias for OCD patients occurs in a later processing stage.</p>

Contact-electrification-activated artificial afferents at femtojoule energy

Low power electronics endowed with artificial intelligence and biological afferent characters are beneficial to neuromorphic sensory network. Highly distributed synaptic sensory neurons are more readily driven by portable, distributed, and ubiquitous power sources. Here, we report a contact-electrification-activated artificial afferent at femtojoule energy. Upon the contact-electrification effect, the induced triboelectric signals activate the ion-gel-gated MoS2 postsynaptic transistor, endowing the artificial afferent with the adaptive capacity to carry out spatiotemporal recognition/sensation on external stimuli (e.g., displacements, pressures and touch patterns). The decay time of the synaptic device is in the range of sensory memory stage. The energy dissipation of the artificial afferents is significantly reduced to 11.9 fJ per spike. Furthermore, the artificial afferents are demonstrated to be capable of recognizing the spatiotemporal information of touch patterns. This work is of great significance for the construction of next-generation neuromorphic sensory network, self-powered biomimetic electronics and intelligent interactive equipment.

Computing Performance Enhancement of VLIW Architecture Using Instruction Level Parallelism

Our paper proposes the new method of processor architecture called as VLIW for enhancing the performance of the architecture. VLIW is the complexity architecture because the enormous number of registers, slices, flip flops, counters, operand, ALUs, and MUXs used. The VLIW has the fife stages of pipelines for executing the architecture are (1) fetching the 128-bit instruction memory, (2) decode stage or it is also called as the operands reading stage because the total number of operands are implemented in this stage, (3) execution stage, here the operations with the parallel executions units which has the four operations, (4) memory stage is used for loading or for storing the data from/to the memory and (5) write back stage in this stage the outputs of all the stage is collected and write back into the register file for storing the output values. The whole process of implementation is implemented in the FPGA of the family of Spartan-6 XC6SLX-3CSG324 device. In this proposed architecture the performance of the architecture is increased by reducing the time taken to execute the CPU of Xst completion of the architecture

Neural Correlates of Visual Short-term Memory Dissociate between Fragile and Working Memory Representations

Evidence is accumulating that the classic two-stage model of visual STM (VSTM), comprising iconic memory (IM) and visual working memory (WM), is incomplete. A third memory stage, termed fragile VSTM (FM), seems to exist in between IM and WM [Vandenbroucke, A. R. E., Sligte, I. G., & Lamme, V. A. F. Manipulations of attention dissociate fragile visual STM from visual working memory. Neuropsychologia, 49, 1559–1568, 2011; Sligte, I. G., Scholte, H. S., & Lamme, V. A. F. Are there multiple visual STM stores? PLoS One, 3, e1699, 2008]. Although FM can be distinguished from IM using behavioral and fMRI methods, the question remains whether FM is a weak expression of WM or a separate form of memory with its own neural signature. Here, we tested whether FM and WM in humans are supported by dissociable time–frequency features of EEG recordings. Participants performed a partial-report change detection task, from which individual differences in FM and WM capacity were estimated. These individual FM and WM capacities were correlated with time–frequency characteristics of the EEG signal before and during encoding and maintenance of the memory display. FM capacity showed negative alpha correlations over peri-occipital electrodes, whereas WM capacity was positively related, suggesting increased visual processing (lower alpha) to be related to FM capacity. Furthermore, FM capacity correlated with an increase in theta power over central electrodes during preparation and processing of the memory display, whereas WM did not. In addition to a difference in visual processing characteristics, a positive relation between gamma power and FM capacity was observed during both preparation and maintenance periods of the task. On the other hand, we observed that theta–gamma coupling was negatively correlated with FM capacity, whereas it was slightly positively correlated with WM. These data show clear differences in the neural substrates of FM versus WM and suggest that FM depends more on visual processing mechanisms compared with WM. This study thus provides novel evidence for a dissociation between different stages in VSTM.

The Encoding/Retrieval Flip: Interactions between Memory Performance and Memory Stage and Relationship to Intrinsic Cortical Networks

fMRI studies have linked the posteromedial cortex to episodic learning (encoding) and remembering (retrieval) processes. The posteromedial cortex is considered part of the default network and tends to deactivate during encoding but activate during retrieval, a pattern known as the encoding/retrieval flip. Yet, the exact relationship between the neural correlates of memory performance (hit/miss) and memory stage (encoding/retrieval) and the extent of overlap with intrinsic cortical networks remains to be elucidated. Using task-based fMRI, we isolated the pattern of activity associated with memory performance, memory stage, and the interaction between both. Using resting-state fMRI, we identified which intrinsic large-scale functional networks overlapped with regions showing task-induced effects. Our results demonstrated an effect of successful memory performance in regions associated with the control network and an effect of unsuccessful memory performance in the ventral attention network. We found an effect of memory retrieval in brain regions that span the default and control networks. Finally, we found an interaction between memory performance and memory stage in brain regions associated with the default network, including the posteromedial cortex, posterior parietal cortex, and parahippocampal cortex. We discuss these findings in relation to the encoding/retrieval flip. In general, the findings demonstrate that task-induced effects cut across intrinsic cortical networks. Furthermore, regions within the default network display functional dissociations, and this may have implications for the neural underpinnings of age-related memory disorders.

MEK inhibitors selectively suppress alloreactivity and graft-versus-host disease in a memory stage-dependent manner

Key Points RAS/MEK/ERK signaling is memory stage-dependent in human T cells, conferring susceptibility to alloreactive T-cell selective inhibition. MEK inhibitors selectively inhibit alloreactive but not herpesvirus-specific human T cells and inhibit murine GVHD.

MEK Inhibitors Selectively Suppress Human T Cell Alloreactivity in a Memory Stage-Dependent Manner,

Abstract 4014 Background: In hematopoietic stem cell transplantation, most immunosuppressive strategies (e.g., using calcineurin inhibitors or corticosteroids) decrease graft-versus-host disease (GVHD) rates, but also impair pathogen- and cancer-specific T cells, increasing treatment-related mortality. Consequently, a key goal of transplant immunology is the identification of more selective inhibitors of alloreactivity. Recent murine studies have shown that alloreactive T cells mediating GVHD reside primarily in naïve and early memory T cell compartments (Anderson BE et al. J Clin Invest 2003;112:101–108, Chen BJ et al. Blood 2004;103:1534–1541, Zheng H et al. J Immunol 2009;182:5938–5948). In contrast, human virus-specific T cells are more differentiated (Gamadia LE et al. Blood 2001;98:754–761). We recently demonstrated that the RAS/MEK/ERK pathway is preferentially activated in naïve and early memory T cells, relative to late memory T cells (Kim TK, submitted). This pathway is activated in a murine experimental GVHD (Lu SX et al. Blood 2008; 112: 5254–5258). Therefore, we hypothesized that MEK inhibition would prove to be a more selective immunosuppressive strategy, suppressing alloreactive but not virus-specific T cells. Design: Using PBMC from healthy donors, we assessed the effects of several MEK inhibitors or the calcineurin inhibitor (CNI) tacrolimus on functional T cell responses using flow cytometry and/or western blotting. Using single-cell cytometric methods, we examined intracellular phosphorylation of ERK1/2 in response to PMA and Ionomycin. Alloreactivity induced by allogeneic monocyte-derived dendritic cell (DC) stimulation was also investigated. CMV-specific functional T cell responses following stimulation using pp65 pentadecapeptide pools were assessed using cytokine flow cytometry. To assess selectivity of immunosuppressive agents, we examined the effects of CNI and MEK inhibitors, independently and in combination, on alloreactivity and CMV-specific T cell responses. Results: We first confirmed that multiple RAS/MEK/ERK family proteins were differentially expressed with lymphocyte maturation, suggesting that MEK inhibitors would preferentially suppress naïve and early memory T cells. Consistent with this prediction, ERK1/2 was preferentially phosphorylated in naïve and early memory T cells stimulated with PMA/Ionomycin, relative to intermediate and late memory T cells. When we examined the effects of targeted T cell inhibition on alloreactive and virus-specific T cell responses, we confirmed that: 1) MEK inhibitors blocked phosphorylation of ERK1/2 in CD4 and CD8 T cells stimulated with PMA/Ionomycin at 100nM to 10μM; 2) Alloreactivity of T cells was suppressed as effectively by MEK inhibitors as by tacrolimus (see Figure 1, left panels). In addition, functional differentiation of naïve T cells was also suppressed. Furthermore, MEK inhibition and calcineurin inhibition worked synergistically and completely shut off alloreactivity. 3) MEK inhibition suppressed cytokine production in naïve and early memory T cells, but not in late memory T cells, while calcineurin inhibition suppressed all differentiation subsets. 4) At doses effectively suppressing DC-stimulated alloreactivity, MEK inhibition spared CMV-specific T cells, in contrast to tacrolimus (p <0.01) (see Figure 1, right panels). Conclusion: MEK inhibitors suppress T cells in a memory stage-dependent manner, suggesting a novel paradigm to achieve selective immunity in the transplant setting. MEK inhibitors abrogate alloreactivity while sparing the function of CMV-specific CD4 and CD8 T cells. These data suggest that MEK inhibitors may serve as a new class of agents with potential activity in GVHD, facilitating selective inhibition of alloreactivity by targeting T cells in a memory stage-dependent manner. Disclosures: No relevant conflicts of interest to declare.