Mindfulness and Fear Conditioning

This is the final version of the article. Available from the publisher via the link in this record.During mindfulness-based interventions participants can be invited to bring aversive stimuli to mind while practicing mindfulness. This is thought to help the stimuli become less aversive. However, the mechanisms underlying this process are not fully understood. In this study we explored these by examining the effects of mindfulness practice and stimulus visualization on stimuli associated with electric shocks. Participants were trained on a discrimination between two visual stimuli using a standard electrodermal conditioning procedure, in which one stimulus (CS+) was paired with shock and the other (CS-) was not. They then visualized either the CS+ or CS-, while practicing mindfulness or performing a control activity. Following a number of extinction trials, the impact of these manipulations was assessed during a reacquisition test-phase. Both mindfulness and visualization of the CS+ led to slower reacquisition of the CS+/shock association, when measured physiologically, and their effects were additive. Moreover, these effects dissociated from participants’ expectancy of shock. If confirmed in future work, these findings may have implications for the treatment of stimulus-specific anxiety.This research was funded by British Academy / Leverhulme Small Research Grant SG150007

Cue Competition in Human Associative Learning

CogSci 2013 - 35th annual meeting of the Cognitive Science Society, Berlin, Germany, 31 July - 3 August 2013There is a question as to whether cue competition effects can be observed in incidental learning paradigms in humans. The SRT and other location prediction tasks fall into that group often considered to show associative learning under incidental conditions. We used a standard SRT task in which the preceding two trials of a run of three predicted the third 2/3 of the time, and added another predictive cue, a colored square, which could also stochastically predict the next response required. The question was to what extent would these two cues compete in terms of incidental learning to make the next response faster and more accurate than controls? We assessed this by comparing the dual cue group to a color only control and a sequence only control. Our results showed that all three groups learned, and that the dual group learned about both cues at least as well as the individual controls, but that when switched to a test phase where each cue could be assessed independently, the dual group showed a marked decline in performance relative to the color control. We interpret this as evidence for overshadowing occurring between the two predictive cues in the dual group, such that when combined their performance is equivalent or superior to either control, but when assessed independently, the color cue actually has a weaker association to the outcome than the equivalent cue in the control group.This research was supported by an ESRC grant to IPL McLaren and FW Jone

Cue Competition in Human Incidental Learning

McLaren, I. P., Jones, F. W., McLaren, R. and Yeates, F. (2013) Cue competition in human incidental learning. In: Reinforcement Learning and Decision Making Meeting 2013, 25th-27th October, Princeton, New Jersey, USA .There is a question as to whether cue competition effects can be observed in incidental learning paradigms in humans. Some authors have reported that cue competition is not observed, and that previous demonstrations of cue competition have relied on explicit awareness of the task in hand. This would imply that these effects are more likely to be the product of cognitive inference than associative learning. We addressed this question by using two paradigms previously shown to produce associative learning under incidental conditions. One was a standard SRT task in which the preceding two trials of a run of three predicted the third 2/3 of the time, and the other was based on another predictive cue, a colored square, which could also stochastically predict the next response required.We have demonstrated in other studies that both cues would support learning under incidental conditions in the absence of any verbalisable knowledge of the rules involved. The question was to what extent would these two cues compete if run concurrently, as assayed by their ability to make the next response faster and more accurate than controls? We assessed this by comparing a dual cue group to a color only control and a sequence only control. Our results showed that all three groups learned, but that during a test phase where each cue could be assessed independently, the dual group showed a marked decline in performance relative to the color control, and very similar performance to the sequence control. We interpret this as evidence for overshadowing occurring between the two predictive cues in the dual group, such that when combined their performance would be equivalent or superior to either control, but when assessed independently, the color cue actually has a weaker association to the outcome than the equivalent cue in the control group. We conclude that the sequence cues overshadowed the color cues in this task, and discuss possible theoretical accounts of this phenomenon

A comprehensive molecular phylogeny of Afrotropical white-eyes (Aves: Zosteropidae) highlights prior underestimation of mainland diversity and complex colonisation history

White-eyes (Zosterops) are a hyper-diverse genus of passerine birds that have rapidly radiated across the Afrotropics and Southeast Asia. Despite their broad range, a disproportionately large number of species are currently recognised from islands compared to the mainland. Described species-level diversity of this ‘great speciator’ from continental Africa-Arabia is strikingly low, despite the vast size and environmental complexity of this region. However, efforts to identify natural groups using traditional approaches have been hindered by the remarkably uniform morphology and plumage of these birds. Here, we investigated the phylogenetic relationships and systematics of Afrotropical Zosterops, including the Gulf of Guinea and western Indian Ocean islands. We included exceptional sampling (∼160 individuals) from all except one subspecies of the 54 taxa (31 species, plus 22 additional named sub-species) currently recognized throughout the region, in addition to a subset of extra-Afrotropical taxa, by exploiting blood and archival samples. Employing a multi-locus phylogenetic approach and applying quantitative species delimitation we tested: 1) if there has been a single colonisation event of the Afrotropical realm; 2) if constituent mainland and island birds are monophyletic; and 3) if mainland diversity has been underestimated. Our comprehensive regional phylogeny revealed a single recent colonisation of the Afrotropical realm c.1.30 Ma from Asia, but a subsequent complex colonisation history between constituent island and mainland lineages during their radiation across this vast area. Our findings suggest a significant previous underestimation of continental species diversity and, based on this, we propose a revised taxonomy. Our study highlights the need to densely sample species diversity across ranges, providing key findings for future conservation assessments and establishing a robust framework for evolutionary studies

Implementation of a Quantum Search Algorithm on a Nuclear Magnetic Resonance Quantum Computer

We demonstrate an implementation of a quantum search algorithm on a two qubit NMR quantum computer based on cytosine.Comment: Six pages, three figure

Physical profiles of elite male field hockey and soccer players - application to sport-specific tests

Background. The physical demands of field hockey and soccer, based on match analysis, are comparable. As a consequence many exercise scientists and coaches have started to use the same type of field tests for hockey and soccer for the purposes of talent identification and training prescription. The validity of this practice is unknown and the data supporting the similarity of the physical attributes of soccer and hockey players are lacking. Objectives. To compare the physical attributes of elite South African hockey and soccer players. Methods. Elite hockey players (N=39: 22±3 years; mean ± standard deviation) and soccer players (N=37; 24±4 years) completed a set of physical tests including a 10 m and 40 m sprint test, a repeated sprint test (sprint fatigue resistance), a 1RM bench press and a push-up test. Results. There were no differences in the 10 m (1.8±0.1 s both groups) and 40 m (5.4±0.2 s v. 5.3±0.2 s; hockey v. soccer) sprint times and distance run in the repeated sprint test (754±14 m v. 734±51 m). The hockey players were stronger (82±16 v. 65±13 kg) and did more push-ups (49±12 v. 38±10 push-ups) than the soccer players. Conclusions. It is acceptable to use the same type of sport-specific tests to measure sprint capacity and sprint fatigue resistance for hockey and soccer players. However, it is questionable whether the normative data derived for upper body strength for soccer players are relevant for hockey players, and vice versa. South African Journal of Sports Medicine Vol. 19 (3) 2007: pp. 74-7

Nasal Lipopolysaccharide Challenge and Cytokine Measurement Reflects Innate Mucosal Immune Responsiveness

<div><p>Background</p><p><b>P</b>ractical methods of monitoring innate immune mucosal responsiveness are lacking. Lipopolysaccharide (LPS) is a component of the cell wall of Gram negative bacteria and a potent activator of Toll-like receptor (TLR)-4. To measure LPS responsiveness of the nasal mucosa, we administered LPS as a nasal spray and quantified chemokine and cytokine levels in mucosal lining fluid (MLF).</p><p>Methods</p><p>We performed a 5-way cross-over, single blind, placebo-controlled study in 15 healthy non-atopic subjects (n = 14 <i>per protocol</i>). Doses of ultrapure LPS (1, 10, 30 or 100μg/100μl) or placebo were administered by a single nasal spray to each nostril. Using the recently developed method of nasosorption with synthetic adsorptive matrices (SAM), a series of samples were taken. A panel of seven cytokines/chemokines were measured by multiplex immunoassay in MLF. mRNA for intercellular cell adhesion molecule-1 (ICAM-1) was quantified from nasal epithelial curettage samples taken before and after challenge.</p><p>Results</p><p>Topical nasal LPS was well tolerated, causing no symptoms and no visible changes to the nasal mucosa. LPS induced dose-related increases in MLF levels of IL-1β, IL-6, CXCL8 (IL-8) and CCL3 (MIP-1α) (AUC at 0.5 to 10h, compared to placebo, p<0.05 at 30 and 100μg LPS). At 100μg LPS, IL-10, IFN-α and TNF-α were also increased (p<0.05). Dose-related changes in mucosal ICAM-1 mRNA were also seen after challenge, and neutrophils appeared to peak in MLF at 8h. However, 2 subjects with high baseline cytokine levels showed prominent cytokine and chemokine responses to relatively low LPS doses (10μg and 30μg LPS).</p><p>Conclusions</p><p>Topical nasal LPS causes dose-dependent increases in cytokines, chemokines, mRNA and cells. However, responsiveness can show unpredictable variations, possibly because baseline innate tone is affected by environmental factors. We believe that this new technique will have wide application in the study of the innate immune responses of the respiratory mucosa.</p><p>Key Messages</p><p>Ultrapure LPS was used as innate immune stimulus in a human nasal challenge model, with serial sampling of nasal mucosal lining fluid (MLF) by nasosorption using a synthetic absorptive matrix (SAM), and nasal curettage of mucosal cells. A dose response could be demonstrated in terms of levels of IL-1β, IL-6, CXCL8 and CCL3 in MLF, as well as ICAM-1 mRNA in nasal curettage specimens, and levels of neutrophils in nasal lavage. Depending on higher baseline levels of inflammation, there were occasional magnified innate inflammatory responses to LPS.</p><p>Trial Registration</p><p>Clinical Trials.gov <a href="https://clinicaltrials.gov/ct2/show/NCT02284074?term=nasal+lipopolysaccharide&rank=1" target="_blank">NCT02284074</a></p></div