Sequential activation of neurons is a common feature of network activity during a variety of behaviors, including working memory and decision making. Previous network models for sequences and memory ...emphasized specialized architectures in which a principled mechanism is pre-wired into their connectivity. Here we demonstrate that, starting from random connectivity and modifying a small fraction of connections, a largely disordered recurrent network can produce sequences and implement working memory efficiently. We use this process, called Partial In-Network Training (PINning), to model and match cellular resolution imaging data from the posterior parietal cortex during a virtual memory-guided two-alternative forced-choice task. Analysis of the connectivity reveals that sequences propagate by the cooperation between recurrent synaptic interactions and external inputs, rather than through feedforward or asymmetric connections. Together our results suggest that neural sequences may emerge through learning from largely unstructured network architectures.
•Sequences emerge in random networks by modifying a small fraction of their connections•Analysis reveals new circuit mechanism for input-dependent sequence propagation•Sequential activation may provide a dynamic mechanism for short-term memory
Rajan et al. show that neural sequences similar to those observed during memory-based decision-making tasks can be generated by minimally structured networks. Sequences may effectively mediate the short-term memory engaged in these tasks.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Pathobiology of Troponin Elevations White, Harvey D., DSc
Journal of the American College of Cardiology,
06/2011, Volume:
57, Issue:
24
Journal Article
Peer reviewed
Open access
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
A number of nonischemic conditions including myocarditis, pulmonary embolism, acute and chronic heart failure, and sepsis may be associated with elevated troponin levels (1,2), although they may ...include supply-demand imbalance and thus at least some element of ischemia. ...there remains the possibility that 60 min of pacing produced myocyte necrosis of a small number of cells without lactate production as measured in this study. ...the conclusion that ischemia alone caused the increase in hs-cTnT levels is not fully substantiated by the study findings.\n Thus, proteolysis to create small fragments could allow these to pass through a cellular membrane with normal membrane integrity.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The amendment of concrete with waste products serves as an avenue to decrease the volume of wastes landfilled and to reduce the use of naturally mined materials, therefore, minimizing the footprint ...and impact that the construction industry has on the environment. This manuscript summarizes the current state of practice with regard to the use of waste products as supplementary cementitious materials (SCM) in portland cement concrete (PCC) and provides a summary of the comparatively sparse information on under-utilized waste materials such as: sugarcane bagasse ash, rice husk ash, waste wood biomass ash, and waste glass. The latter are all waste products that have the potential to be employed alongside traditional SCM, however much of the use to date has been done at the laboratory scale. This document will serve as a guide for the use of non-traditional waste SCM, to highlight areas likely requiring further refinement or research, and to indicate potential negative impacts from utilization of these products that might occur. The beneficial use of waste materials as SCM outside the United States has grown in recent years, mainly out of necessity; however, current research indicates that these materials typically provide a benefit when amending PCC and mortar.
•The state of the knowledge of the addition of supplementary cementitious materials to PCC reviewed.•Waste SCMs offer benefits to PCC, currently many are underutilized.•Limited data on long term durability of PCC amended with waste SCMs.•Data on available quantities and production of SCMs compiled.•Impact of waste SCM addition on mix properties tabulated.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
The primary aim of treating patients with stable angina is to decrease symptoms and improve quality of life. Percutaneous coronary intervention (PCI), a treatment for patients with angina, does not ...reduce the risk of death from any cause, death from cardiac causes, or myocardial infarction.
1
In this issue of the
Journal
, Rajkumar and colleagues
2
report on the results of the ORBITA-2 trial, which is the first double-blind, randomized, placebo-controlled trial to show that PCI is an effective antianginal treatment in patients with stable angina who have objective evidence of ischemia. ORBITA-2 was an elegant and rigorous trial that was designed . . .
Abstract
Social cognition is increasingly recognized as an important treatment target in schizophrenia; however, the dearth of well-validated measures that are suitable for use in clinical trials ...remains a significant limitation. The Social Cognition Psychometric Evaluation (SCOPE) study addresses this need by systematically evaluating the psychometric properties of promising measures. In this final phase of SCOPE, eight new or modified tasks were evaluated. Stable outpatients with schizophrenia (n = 218) and healthy controls (n = 154) completed the battery at baseline and 2–4 weeks later across three sites. Tasks included the Bell Lysaker Emotion Recognition Task (BLERT), Penn Emotion Recognition Task (ER-40), Reading the Mind in the Eyes Task (Eyes), The Awareness of Social Inferences Test (TASIT), Hinting Task, Mini Profile of Nonverbal Sensitivity (MiniPONS), Social Attribution Task—Multiple Choice (SAT-MC), and Intentionality Bias Task (IBT). BLERT and ER-40 modifications included response time and confidence ratings. The Eyes task was modified to include definitions of terms and TASIT to include response time. Hinting was scored with more stringent criteria. MiniPONS, SAT-MC, and IBT were new to this phase. Tasks were evaluated on (1) test-retest reliability, (2) utility as a repeated measure, (3) relationship to functional outcome, (4) practicality and tolerability, (5) sensitivity to group differences, and (6) internal consistency. Hinting, BLERT, and ER-40 showed the strongest psychometric properties and are recommended for use in clinical trials. Eyes, TASIT, and IBT showed somewhat weaker psychometric properties and require further study. MiniPONS and SAT-MC showed poorer psychometric properties that suggest caution for their use in clinical trials.
The cortex represents information across widely varying timescales. For instance, sensory cortex encodes stimuli that fluctuate over few tens of milliseconds, whereas in association cortex ...behavioural choices can require the maintenance of information over seconds. However, it remains poorly understood whether diverse timescales result mostly from features intrinsic to individual neurons or from neuronal population activity. This question remains unanswered, because the timescales of coding in populations of neurons have not been studied extensively, and population codes have not been compared systematically across cortical regions. Here we show that population codes can be essential to achieve long coding timescales. Furthermore, we find that the properties of population codes differ between sensory and association cortices. We compared coding for sensory stimuli and behavioural choices in auditory cortex and posterior parietal cortex as mice performed a sound localization task. Auditory stimulus information was stronger in auditory cortex than in posterior parietal cortex, and both regions contained choice information. Although auditory cortex and posterior parietal cortex coded information by tiling in time neurons that were transiently informative for approximately 200 milliseconds, the areas had major differences in functional coupling between neurons, measured as activity correlations that could not be explained by task events. Coupling among posterior parietal cortex neurons was strong and extended over long time lags, whereas coupling among auditory cortex neurons was weak and short-lived. Stronger coupling in posterior parietal cortex led to a population code with long timescales and a representation of choice that remained consistent for approximately 1 second. In contrast, auditory cortex had a code with rapid fluctuations in stimulus and choice information over hundreds of milliseconds. Our results reveal that population codes differ across cortex and that coupling is a variable property of cortical populations that affects the timescale of information coding and the accuracy of behaviour.
Full text
Available for:
IJS, KISLJ, NUK, SBMB, UL, UM, UPUK
A molecular description of the control of floral pigmentation in a multi-species group displaying various flower color patterns is of great interest for understanding the molecular bases of ...phenotypic diversification and pollinator-mediated speciation.
Through transcriptome profiling, mutant analyses and transgenic experiments, we aim to establish a ‘baseline’ floral anthocyanin regulation model in Mimulus lewisii and to examine the different ways of tinkering with this model in generating the diversity of floral anthocyanin patterns in other Mimulus species.
We find one WD40 and one bHLH gene controlling anthocyanin pigmentation in the entire corolla of M. lewisii and two R2R3-MYB genes, PELAN and NEGAN, controlling anthocyanin production in the petal lobe and nectar guide, respectively. The autoregulation of NEGAN might be a critical property to generate anthocyanin spots. Independent losses of PELAN expression (via different mechanisms) explain two natural yellow-flowered populations of M. cardinalis (typically red-flowered). The NEGAN ortholog is the only anthocyanin-activating MYB expressed in the M. guttatus flowers.
The mutant lines and transgenic tools available for M. lewisii will enable gene-by-gene replacement experiments to dissect the genetic and developmental bases of more complex floral color patterns, and to test hypotheses on phenotypic evolution in general.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NMLJ, NUK, OILJ, PNG, SAZU, SBCE, SBMB, UL, UM, UPUK
PDF
