899 research outputs found
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Disrupted GABAergic facilitation of working memory performance in people with schizophrenia.
ObjectivesGamma-Amiobutyric acid (GABA) is a primary inhibitory neurotransmitter that facilitates neural oscillations that coordinate neural activity between brain networks to facilitate cognition. The present magnetic resonance spectroscopy (MRS) study tests the hypothesis that GABAergic facilitation of working memory is disrupted in people with schizophrenia (PSZ).Methods51 healthy participants and 40 PSZ from the UC Davis Early Psychosis Program performed an item and temporal order working memory (WM) task and underwent resting MRS to measure GABA and glutamate concentrations in dorsolateral prefrontal (DLPFC) and anterior cingulate (ACC) regions of interest. MRS was acquired on a 3 Tesla Siemens scanner and GABA and glutamate concentrations were referenced to creatine. Percent correct on the WM task indexed performance and correlation coefficients examined GABAergic or Glutamatergic facilitation of WM, with Fisher's Z transformation testing for group differences.ResultsThere were no group differences in GABA or glutamate concentrations, but WM correlations were reversed between groups. In patients, higher DLPFC GABA was associated with worse rather than better WM performance. This pattern was not observed for glutamate or in the ACC. Although under-powered, there was no indication of medication effects.Conclusions and relevanceResults cannot be explained by group differences in DLPFC GABA or glutamate concentrations but, instead, indicate that schizophrenia disrupts the GABAergic facilitation of WM seen in healthy individuals. Results appear to parallel post mortem findings in suggesting that schizophrenia alters the distribution of different classes of GABAergic interneurons rather than producing a general deficit across the total population of neurons
Impact of schizophrenia on anterior and posterior hippocampus during memory for complex scenes.
ObjectivesHippocampal dysfunction has been proposed as a mechanism for memory deficits in schizophrenia. Available evidence suggests that the anterior and posterior hippocampus could be differentially affected. Accordingly, we used fMRI to test the hypothesis that activity in posterior hippocampus is disproportionately reduced in schizophrenia, particularly during spatial memory retrieval.Methods26 healthy participants and 24 patients with schizophrenia from the UC Davis Early Psychosis Program were studied while fMRI was acquired on a 3 Tesla Siemens scanner. During encoding, participants were oriented to critical items through questions about item features (e.g., "Does the lamp have a square shade?") or spatial location (e.g., "Is the lamp on the table next to the couch?"). At test, participants determined whether scenes were changed or unchanged. fMRI analyses contrasted activation in a priori regions of interest (ROI) in anterior and posterior hippocampus during correct recognition of item changes and spatial changes.ResultsAs predicted, patients with schizophrenia exhibited reduced activation in the posterior hippocampus during detection of spatial changes but not during detection of item changes. Unexpectedly, patients exhibited increased activation of anterior hippocampus during detection of item changes. Whole brain analyses revealed reduced fronto-parietal and striatal activation in patients for spatial but not for item change trials.ConclusionsResults suggest a gradient of hippocampal dysfunction in which posterior hippocampus - which is necessary for processing fine-grained spatial relationships - is underactive, and anterior hippocampus - which may process context more globally - is overactive
Control dependence for extended finite state machines
Though there has been nearly three decades of work on program slicing, there has been comparatively little work on slicing for state machines. One of the primary challenges that currently presents a barrier to wider application of state machine slicing is the problem of determining control dependence. We survey existing related definitions, introducing a new definition that subsumes one and extends another. We illustrate that by using this new definition our slices respect Weiser slicing’s termination behaviour. We prove results that clarify the relationships between our definition and older ones, following this up with examples to motivate the need for these differences
A Numerical Model Study for Development of a Harbour Layout in a Creek with Wide Tidal Flat
Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchiv
Event boundaries shape temporal organization of memory by resetting temporal context
In memory, our continuous experiences are broken up into discrete events. Boundaries between events are known to influence the temporal organization of memory. However, how and through which mechanism event boundaries shape temporal order memory (TOM) remains unknown. Across four experiments, we show that event boundaries exert a dual role: improving TOM for items within an event and impairing TOM for items across events. Decreasing event length in a list enhances TOM, but only for items at earlier local event positions, an effect we term the local primacy effect. A computational model, in which items are associated to a temporal context signal that drifts over time but resets at boundaries captures all behavioural results. Our findings provide a unified algorithmic mechanism for understanding how and why event boundaries affect TOM, reconciling a long-standing paradox of why both contextual similarity and dissimilarity promote TOM
A prospective study on the use of anesthetic agents in modern surgical practice at a tertiary care hospital, Karnataka, India
Background: The choice of local anesthetic is based on potency of the agent, onset and duration of anesthesia, and side effects of the drug Objectives of the study were, the study proposes to analysis the pattern, trend, rationality and frequency of use of anesthetic agents in modern surgical procedures.Methods: The study records relevant data obtained from surgical case records of patients from department of General surgery, Obstetrics and Gynecology and Orthopedics during the period December 2014 to May 2015 including first one month of pilot study, at KVGMC, Sullia (D.K), Karnataka.Results: A total of 744 cases were collected and screened according to inclusion and exclusion criteria and finally 348 cases were recorded and critically analysed. Sub-arachnoid block is the most common type of anesthetic procedure (75.28%) performed by the anesthetists. Of 348 cases undergoing anesthesia using local anesthetic agents, 228 cases required only a single agent and 120 cases required a combination anesthetic agents. 206 underwent sub-arachnoid block, 16 epidural block (EPID) and only 2 brachial block. The most commonly used agent for maintainence of general anesthesia is Isoflurane (68%) followed by Halothane (32%) and the combination of skeletal muscle relaxants were Succinylcholine with either Atracurium (39.8%) or Vecuronium (37.16%). Analgesics were the most commonly used adjuvants followed by ondansetron.Conclusions: The study showed that the most common anesthetic procedure performed using local anesthetic agents is SA/SAB block and the most common agent used is bupivacaine which was frequently employed at the dose range of 3-4 ml. There was significant association found between the no. of anesthetic agents used and the type of anesthetic procedure performed and also between the concerned department and the type of anesthetic procedure performed. Thus, the rationality in the usage of relevant anesthetic agents with appropriate adjuvants is evident
Learning Invariant Representations with Missing Data
Spurious correlations allow flexible models to predict well during training
but poorly on related test distributions. Recent work has shown that models
that satisfy particular independencies involving correlation-inducing
\textit{nuisance} variables have guarantees on their test performance.
Enforcing such independencies requires nuisances to be observed during
training. However, nuisances, such as demographics or image background labels,
are often missing. Enforcing independence on just the observed data does not
imply independence on the entire population. Here we derive \acrshort{mmd}
estimators used for invariance objectives under missing nuisances. On
simulations and clinical data, optimizing through these estimates achieves test
performance similar to using estimators that make use of the full data.Comment: CLeaR (Causal Learning and Reasoning) 202
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Impaired recollection of visual scene details in adults with autism spectrum conditions.
Subtle memory deficits observed in autism spectrum conditions (ASC) have often been characterized as reflecting impaired recollection and it has been proposed that a relational binding deficit may underlie the recollection impairment. However, subjective recollection and relational binding have not been measured within the same task in ASC to date and it is unclear whether a relational binding deficit can provide a full account of recollection impairments in ASC. Relational memory has also not been compared with item memory when the demands of the 2 tasks are comparable. To assess recollection, relational memory, and item memory within a single task in ASC, 24 adults with ASC and 24 typically developed adults undertook a change detection memory task that assessed recollection of item-specific and spatial details. Participants studied rendered indoor and outdoor scenes and, in a subsequent recognition memory test, distinguished scenes that had not changed from those that had either undergone an item change (a different item exemplar) or a relational (spatial) change, which was followed by a subjective recollection judgment. The ASC group identified fewer item changes and spatial changes, to a similar degree, which was attributable to a specific reduction in recollection-based recognition relative to the control group. These findings provide evidence that recollection deficits in ASC may not be driven entirely by a relational binding deficit.This research was supported by a James S. McDonnell Scholar Award to J.S.S., an Economic and Social Research Council Award to R.A.C., and Leverhulme Trust Visiting Professorship and Parke Davis Exchange Fellowship Awards to C.R.This is the author accepted manuscript. The final version is available from he American Psychological Association via http://dx.doi.org/10.1037/abn000007
Pheromone Trapping Protocols for Brinjal Shoot and Fruit Borer, Leucinodes orbonalis Guenee (Lepidoptera: Pyralidae): Evaluation of Trap Design, Quantity and Dispenser
Studies were conducted at the Indian Institute of Horticultural Research, Bangalore, and Central Horticultural Experiment Station, Bhubaneshwar, India, to evaluate trap design, quantity of pheromone loading and dispensers for attracting brinjal shoot and fruit borer, Leucinodes orbonalis Guenee (Lepidoptera: Pyralidae) using indigenously synthesized pheromone lure [synthesized by Indian Institute of Chemical Technology (IICT), Hyderabad], during 2003 and 2004. A water trap consisting of plastic container (20 cm dia. and 7.5 cm depth) with a facility to place the pheromone septum was designed. Pheromone load of 4 mg in both water trap and Pest Control India (PCI®) delta trap was observed to catch higher number of male moths compared to dispensers with lesser loading. When trap designs were compared, water trap with pheromone lure was observed to attract higher number of males than Pest Control India (PCI®) delta trap. Among the different pheromone dispensers tested, rubber septum was superior to plastic vial or plastic septum. Rubber septum supplied by Bio Pest Management® captured significantly higher number of moths compared to rubber and plastic septum supplied by difTerent firms. A comparison of IICT synthesized lures along with some commercially available lures indicated that Bio Pest Management® lure dispensed in rubber outperformed PCI® and IICT lures
Tuberculosis-diabetes mellitus bidirectional screening at a tertiary care centre, South India
Supported by the TB Union/MSF Course on Operational Researc
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