Drinking the waters of Lethe: Bringing voluntary choice into the study of voluntary forgetting.

The directed forgetting paradigm has long been used to test whether humans can voluntarily choose to forget learned information. However, to date, nearly all directed forgetting paradigms have involved a forced-choice paradigm, in which the participants are instructed about which learned information they should forget. While studies have repeatedly shown that this directed forgetting does lead to a decreased ability to later remember the information, it is still unclear whether these effects would be present if participants were allowed to, of their own accord, choose which information they wanted to forget. In two experiments here, we introduce a free-choice variety of the item method directed forgetting paradigm and show that directed forgetting effects are robust, both for instructed and voluntary forgetting. We discuss the implications of our findings for notions of voluntary forgetting and for the self-choice effect in memory.

Odor associated memories are not necessarily highly emotional.

Laboratory and clinical studies have shown that odors tend to evoke highly emotional autobiographical memories that frequently come from an early period in life. One potential explanation for this effect is that all memories associated with odors are particularly emotional, while another potential explanation is that the presence of an (emotional) odor during retrieval leads to the participants' impression that the retrieved memory is particularly emotional. To this point, nearly all research on odor evoked autobiographical memories has relied on the presence of an odor to cue the memory, a procedure that does not allow one to distinguish whether the emotionality of the memories is due to the memory itself or the presence of the current cue. In contrast, in the current studies, no stimuli were presented during the retrieval of autobiographical memories. Instead, we asked people to report on memories specifically associated with the five traditional different senses or asked for information about autobiographical memories evoked throughout the day and assessed the role of the senses in those experienced memories. Across the three studies, using slightly different methodologies, we found that odor associated autobiographical memories are not more emotional or older than memories (mainly) associated with other modalities. Our results carefully put into question the notion that odor associated autobiographical memories are more emotional than autobiographical memories mostly associated with other modalities. Since the difference between the presented and previous studies lies in a different situation at AM retrieval, these results present evidence towards retrieval-based explanations.

Gamma-aminobutyric acid-producing lactobacilli positively affect metabolism and depressive-like behaviour in a mouse model of metabolic syndrome.

Metabolic and neuroactive metabolite production represents one of the mechanisms through which the gut microbiota can impact health. One such metabolite, gamma-aminobutyric acid (GABA), can modulate glucose homeostasis and alter behavioural patterns in the host. We previously demonstrated that oral administration of GABA-producing Lactobacillus brevis DPC6108 has the potential to increase levels of circulating insulin in healthy rats. Therefore, the objective of this study was to assess the efficacy of endogenous microbial GABA production in improving metabolic and behavioural outcomes in a mouse model of metabolic dysfunction. Diet-induced obese and metabolically dysfunctional mice received one of two GABA-producing strains, L. brevis DPC6108 or L. brevis DSM32386, daily for 12 weeks. After 8 and 10 weeks of intervention, the behavioural and metabolic profiles of the mice were respectively assessed. Intervention with both L. brevis strains attenuated several abnormalities associated with metabolic dysfunction, causing a reduction in the accumulation of mesenteric adipose tissue, increased insulin secretion following glucose challenge, improved plasma cholesterol clearance and reduced despair-like behaviour and basal corticosterone production during the forced swim test. Taken together, this exploratory dataset indicates that intervention with GABA-producing lactobacilli has the potential to improve metabolic and depressive- like behavioural abnormalities associated with metabolic syndrome in mice.

An in-depth review of the methods, findings, and theories associated with odor-evoked autobiographical memory.

Over the past nearly 35 years, there has been sporadic interest in what has commonly come to be known as the Proust phenomenon, whereby autobiographical memories are retrieved and experienced differently when evoked by odors as compared with other types of cues, such as words, images or sounds. The purpose of this review is threefold. First, we provide a detailed analysis of the methods used to investigate Proust effects. Second, we review and analyze the various findings from the literature and determine what we feel to be the most important and stable findings. Third, we provide a series of previously postulated and new hypotheses that attempt to account for the various findings. Given the early stage of research, the current review aims to provide a measure of organization to the field, as well serve as a guide for how future investigations may address the topic. We conclude with the recommendation that research in this area shift its focus from establishing the phenomenon towards explaining its causes.

Olfactory Context Dependent Memory: Direct Presentation of Odorants.

Information is retrieved more effectively when the retrieval occurs in the same context as that in which the information was first encoded. This is termed context dependent memory (CDM). One category of cues that have been shown to effectively produce CDM effects are odors. However, it is unclear what the boundary conditions of these CDM effects are. In particular, given that olfaction has been called an implicit sense, it is possible that odors are only effective mnemonic cues when they are presented in the background. This assertion seems even more likely given that previous research has shown odors to be poor cues during paired associate memory tests, where odors are in the focus of attention as mnemonic cues for other information. In order to determine whether odors are only effective contextual mnemonic cues when presented outside the central focus of an observer, an olfactory CDM experiment was performed in which odorants were presented directly, rather than ambiently. Direct presentation was accomplished with the aid of an olfactometer. The olfactometer not only allows for direct presentation of odorants, but provides other methodological benefits, including the allowance of trial by trial manipulations of odorant presentations and, relatedly, time-specific releases of odorants. The presence of the same odor during both encoding and retrieval enhanced memory performance, regardless of whether the odor was presented ambiently or directly. This finding can serve as a basis for future olfactory CDM research which can utilize the benefits of direct presentation.

Impact of beneficial bacteria supplementation on the gut microbiota, colony development and productivity of Apis mellifera L.

Honey bees are important pollinators of several crops and ecosystems, having a great ecological and economic value. In Europe, the restricted use of chemicals and therapeutic agents in the beekeeping sector has stimulated the search for natural alternatives with a special focus on gut symbionts. The modulation of the gut microbiota has been recognised as a practical and successful approach in the entomological field for the management of insect-related problems. To date, only a few studies have investigated the effect of bacterial supplementation on the health status of colonies, colony productivity and gut symbionts. To this purpose, a preparation of sugar syrup containing bifidobacteria and lactobacilli isolated from bee gut was sprayed on the frames of an apiary located in open field once a week for four weeks. Treated and control hives were monitored for two months for brood extension, honey and pollen harvest. The presence of beneficial gut microorganisms within bee gut was investigated with denaturing gradient gel electrophoresis and next generation sequencing. The administered bacteria led to a significant increase of brood population (46.2%), pollen (53.4%) and harvestable honey in honey supers (59.21%). Analysis of the gut microbiota on the new generation of bees in treated hives showed an increase in relative abundance of Acetobacteraceae and Bifidobacterium spp., which are known to be involved in bee nutrition and protection.

Olfactory Context-Dependent Memory and the Effects of Affective Congruency.

Odors have been claimed to be particularly effective mnemonic cues, possibly because of the strong links between olfaction and emotion processing. Indeed, past research has shown that odors can bias processing towards affectively congruent material. In order to determine whether this processing bias translates to memory, we conducted 2 olfactory-enhanced-context memory experiments where we manipulated affective congruency between the olfactory context and to-be-remembered material. Given the presumed importance of valence to olfactory perception, we hypothesized that memory would be best for affectively congruent material in the olfactory enhanced context groups. Across the 2 experiments, groups which encoded and retrieved material in the presence of an odorant exhibited better memory performance than groups that did not have the added olfactory context during encoding and retrieval. While context-enhanced memory was exhibited in the presence of both pleasant and unpleasant odors, there was no indication that memory was dependent on affective congruency between the olfactory context and the to-be-remembered material. While the results provide further support for the notion that odors can act as powerful contextual mnemonic cues, they call into question the notion that affective congruency between context and focal material is important for later memory performance.

Reduced-fat Cheddar and Swiss-type cheeses harboring exopolysaccharide-producing probiotic Lactobacillus mucosae DPC 6426.

Exopolysaccharide-producing Lactobacillus mucosae DPC 6426 was previously shown to have promising hypocholesterolemic activity in the atherosclerosis-prone apolipoprotein-E-deficient (apoE(-/-)) murine model. The aim of this study was to investigate the suitability of reduced-fat Cheddar and Swiss-type cheeses as functional (carrier) foods for delivery of this probiotic strain. All cheeses were manufactured at pilot-scale (500-L vats) in triplicate, with standard commercially available starters: for Cheddar, Lactococcus lactis; and for Swiss-type cheese, Streptococcus thermophilus, Lactobacillus helveticus, and Propionibacterium freudenreichii. Lactobacillus mucosae DPC 6426 was used as an adjunct culture during cheese manufacture, at a level of ~10(6) cfu·mL(-1) cheese milk (subsequently present in the cheese curd at>10(7) cfu·g(-1)). The adjunct strain remained viable at >5×10(7) cfu·g(-1) in both Swiss-type and Cheddar cheeses following ripening for 6 mo. Sensory analysis revealed that the presence of the adjunct culture imparted a more appealing appearance in Swiss-type cheese, but had no significant effect on the sensory characteristics of Cheddar cheeses. Moreover, the adjunct culture had no significant effect on cheese composition, proteolysis, pH, or instrumentally quantified textural characteristics of Cheddar cheeses. These data indicate that low-fat Swiss-type and Cheddar cheeses represent suitable food matrices for the delivery of the hypocholesterolemic Lactobacillus mucosae DPC 6426 in an industrial setting.

Sugar-coated: exopolysaccharide producing lactic acid bacteria for food and human health applications.

The human enteric microbiome represents a veritable organ relied upon by the host for a range of metabolic and homeostatic functions. Through the production of metabolites such as short chain fatty acids (SCFA), folate, vitamins B and K, lactic acid, bacteriocins, peroxides and exopolysaccharides, the bacteria of the gut microbiome provide nutritional components for colonocytes, liver and muscle cells, competitively exclude potential pathogenic organisms and modulate the hosts immune system. Due to the extensive variation in structure, size and composition, microbial exopolysaccharides represent a useful set of versatile natural ingredients for the food industrial sector, both in terms of their rheological properties and in many cases, their associated health benefits. The exopolysaccharide-producing bacteria that fall within the 35 Lactobacillus and five Bifidobacterium species which have achieved qualified presumption of safety (QPS) and generally recognised as safe (GRAS) status are of particular interest, as their inclusion in food products can avoid considerable scrutiny. In addition, additives commonly utilised by the food industry are becoming unattractive to the consumer, due to the demand for a more 'natural' and 'clean labelled' diet. In situ production of exopolysaccharides by food-grade cultures in many cases confers similar rheological and sensory properties in fermented dairy products, as traditional additives, such as hydrocolloids, collagen and alginate. This review will focus on microbial synthesis of exopolysaccharides, the human health benefits of dietary exopolysaccharides and the technofunctional applications of exopolysaccharide-synthesising microbes in the food industry.

Using X-mode L, R and O-mode reflectometry cutoffs to measure scrape-off-layer density profiles for upgraded ORNL reflectometer on NSTX-U.

The pre-existing ORNL scrape-off-layer (SOL) reflectometer that operated with the X-mode R-cutoff at 6-27 GHz to measure SOL density profiles on NSTX is being upgraded to be functional at the increased magnetic fields on NSTX-U spherical tokamak. Rather than increasing the operating frequencies to measure the higher X-mode R-cutoff frequencies on NSTX-U, it will be shown that the combined use of the X-mode R, L and O-mode cutoffs at 6-27 GHz can obtain the desired SOL density profiles. The potential capabilities and obstacles of this technique to measure SOL density profiles and possibly SOL magnetic field profiles on NSTX-U will be discussed.

High-harmonic fast-wave power flow along magnetic field lines in the scrape-off layer of NSTX.

A significant fraction of high-harmonic fast-wave (HHFW) power applied to NSTX can be lost to the scrape-off layer (SOL) and deposited in bright and hot spirals on the divertor rather than in the core plasma. We show that the HHFW power flows to these spirals along magnetic field lines passing through the SOL in front of the antenna, implying that the HHFW power couples across the entire width of the SOL rather than mostly at the antenna face. This result will help guide future efforts to understand and minimize these edge losses in order to maximize fast-wave heating and current drive.

Predicting high harmonic ion cyclotron heating efficiency in Tokamak plasmas.

Observations of improved radio frequency (rf) heating efficiency in ITER relevant high-confinement (H-)mode plasmas on the National Spherical Tokamak Experiment are investigated by whole-device linear simulation. The steady-state rf electric field is calculated for various antenna spectra and the results examined for characteristics that correlate with observations of improved or reduced rf heating efficiency. We find that launching toroidal wave numbers that give fast-wave propagation in the scrape-off plasma excites large amplitude (∼kV m(-1)) coaxial standing modes between the confined plasma density pedestal and conducting vessel wall. Qualitative comparison with measurements of the stored plasma energy suggests that these modes are a probable cause of degraded heating efficiency.

14-3-3 (Bmh) proteins inhibit transcription activation by Adr1 through direct binding to its regulatory domain.

14-3-3 proteins, known as Bmh in yeast, are ubiquitous, highly conserved proteins that function as adaptors in signal transduction pathways by binding to phosphorylated proteins to activate, inactivate, or sequester their substrates. Bmh proteins have an important role in glucose repression by binding to Reg1, the regulatory subunit of Glc7, a protein phosphatase that inactivates the AMP-activated protein kinase Snf1. We describe here another role for Bmh in glucose repression. We show that Bmh binds to the Snf1-dependent transcription factor Adr1 and inhibits its transcriptional activity. Bmh binds within the regulatory domain of Adr1 between amino acids 215 and 260, the location of mutant ADR1(c) alleles that deregulate Adr1 activity. This provides the first explanation for the phenotype resulting from these mutations. Bmh inhibits Gal4-Adr1 fusion protein activity by binding to the Ser230 region and blocking the function of a nearby cryptic activating region. ADR1(c) alleles, or the inactivation of Bmh, relieve the inhibition and Snf1 dependence of this activating region, indicating that the phosphorylation of Ser230 and Bmh are important for the inactivation of Gal4-Adr1. The Bmh binding domain is conserved in orthologs of Adr1, suggesting that it acquired an important biological function before the whole-genome duplication of the ancestor of S. cerevisiae.

Optimization of multi-walled carbon nanotube-metal contacts by electrical stressing.

We present experimental data on the contact resistances of three different metal probes, tungsten, palladium and indium, with chemical vapour deposited (CVD) multi-wall carbon nanotubes (MWCNTs). We demonstrate that there is an irreversible modification of the contacts following electrical stressing whereby the circuit resistance converges towards its optimal value prior to current-induced tube failure. Once the probe-MWCNT contact is broken, subsequent recontact experiments reveal that the circuit resistance returns to its initial high level, demonstrating that the modification occurs at the probe contact location and not elsewhere in the circuit. Contact studies with the different metals reveal that Pd metal provides the lowest resistance contact to the MWCNT in our sample.

Emergence and visualization of an interface state during contact formation with a single molecule.

Contact formation dynamics and electronic perturbations arising from the interaction of a metallic probe and a single molecule (1,3 cyclohexadiene) bound on the Si (100) surface are examined using a series of plane wave, density functional theory calculations. The approach of the probe induces a relaxation of the molecule that ultimately leads to the formation of an interface state due to a specific interaction between the probe apex atom and the C=C bond of the molecule. The calculated interface state is located 0.2 eV above the Fermi energy, in agreement with low temperature scanning tunneling spectroscopy local density of states data (0.35 eV), and is responsible for the contrast observed in low bias empty-state STM images.

Short-scale turbulent fluctuations driven by the electron-temperature gradient in the national spherical torus experiment.

Measurements with coherent scattering of electromagnetic waves in plasmas of the National Spherical Torus Experiment indicate the existence of turbulent fluctuations in the range of wave numbers k perpendicular rho(e)=0.1-0.4, corresponding to a turbulence scale length nearly equal to the collisionless skin depth. Experimental observations and agreement with numerical results from a linear gyrokinetic stability code support the conjecture that the observed turbulence is driven by the electron-temperature gradient.

The toxicity profile of a single dose of paroxetine: an alternative approach to acute toxicity testing in the rat.

In this study we have examined the effect of a single administration of the selective serotonin reuptake inhibitor, paroxetine (120-300 mg kg(-1), orally) in a recently developed rodent model of acute toxicity testing. Reduced body-weight, food consumption, water consumption and body temperature were observed in all paroxetine-treated groups, which were reversible within 7 days. Five days after administration, a dose-dependent increase in red blood cells, haemoglobin and haematocrit was observed with the 3 higher dose levels of paroxetine, which was significant in the 240 and 300 mg kg(-1) treatment groups (P < 0.05). Hyperactivity was apparent in the first 24 hr following treatment, as was evidence of the serotonin syndrome. When the animals were sacrificed (11 days after drug administration), an increase in liver weight was observed in the highest dose. These results are in agreement with those previously observed with paroxetine at the preclinical and clinical levels. They demonstrate that this rodent model, because of its multi-parameter nature, is a useful method for examining the consequences of a single high dose of an antidepressant drug.

Extracting parity and magnitude from Arabic numerals: developmental changes in number processing and mental representation.

Children from Grades 2, 3, 4, 6, and 8 (7.8, 9.2, 9.8, 11.7, and 13. 6 years old, respectively) made speeded, bimanual parity (odd/even) judgments of the Arabic numerals 0-9. Analysis of response times indicated that from fourth grade on, parity information is retrieved directly from memory rather than being extracted by means of a mental calculation strategy. As early as Grade 3, children exhibited the SNARC (Spatial-Numerical Association of Response Codes) effect, where small numbers were responded to faster with the left hand than with the right hand, while the converse held true for large numbers. This finding, previously demonstrated only in adults, confirms that (a) children represent magnitude information in the form of a left-to-right oriented mental number line, and (b) this information is accessed obligatorily even when irrelevant. Finally, although the SNARC effect remained strong at Grade 4, it was attenuated at Grades 6 and 8 by a linguistic effect based on associations between the unmarked adjectives "even" and "right" and between the marked adjectives "odd" and "left."

The characterization of oxotremorine-induced hypothermic response in the rat.

Oxotremorine is a muscarinic receptor agonist that induces a variety of physiological and behavioural effects including hypothermia in mice. These effects are antagonized dose-dependently by classical anticholinergic compounds such as atropine. Although the oxotremorine-induced hypothermic response has been demonstrated in mice, few studies of the effects of this muscarinic agonist have been made in the rat. The following studies were made in male Sprague Dawley rats: 1. an investigation of the dose-response relationship between oxotremorine and hypothermia; 2. an examination of the effect of housing on the oxotremorine-induced hypothermic response, and 3, an investigation of the acute administration of various doses of atropine sulphate on the hypothermia caused by oxotremorine. The results indicate that the dose-response relationship between oxotremorine and the antagonism of hypothermia is similar in rat as it is in mice. The results also showed that this effect did not occur in group-housed animals.

Epidemiology, etiology, diagnosis, and treatment of schizophrenia.

The epidemiology, etiology, diagnosis, and treatment of schizophrenia are reviewed. In the United States, at least 1 in every 100 persons is afflicted with schizophrenia. The theory that schizophrenia is a biochemical disorder has gained wide acceptance, although none of the etiological theories are conclusive. Criteria contained in the Diagnostic and Statistical Manual of Mental Disorders, Third Edition, Revised, are most commonly used to diagnose schizophrenia. Accuracy in diagnosing schizophrenia is critical because the treatments and prognoses for different types of psychoses can vary considerably. Treatment primarily involves the use of antipsychotic drugs, which are thought to act by blocking central dopamine receptors. The classical antipsychotics are the phenothiazines; of these, the prototype is chlorpromazine. Other classes of antipsychotics are the thioxanthenes, butyrophenones, dihydroindolones, dibenzoxazepines, diphenylbutylpiperidines, and dibenzodiazepines. Selecting an appropriate agent involves consideration of adverse effects, dosage forms, and the agent's ability to relieve target symptoms. Adverse effects of these agents include sedation, extrapyramidal effects, and anticholinergic effects. Tardive dyskinesia is a serious, irreversible condition associated with long-term antipsychotic therapy. Clozapine, a newer atypical antipsychotic, has been shown to be more effective than chlorpromazine and haloperidol and seems to cause few neurological adverse effects. Treatment of schizophrenia has not changed much since the advent of antipsychotic drug use nearly 30 years ago. Newer atypical antipsychotics show promise in improving target symptoms while causing fewer adverse effects.