Evaluative conditioning in humans: A meta-analysis.

This article presents a meta-analysis of research on evaluative conditioning (EC), defined as a change in the liking of a stimulus (conditioned stimulus; CS) that results from pairing that stimulus with other positive or negative stimuli (unconditioned stimulus; US). Across a total of 214 studies included in the main sample, the mean EC effect was d = .52, with a 95% confidence interval of .466–.582. As estimated from a random-effects model, about 70% of the variance in effect sizes were attributable to true systematic variation rather than sampling error. Moderator analyses were conducted to partially explain this variation, both as a function of concrete aspects of the procedural implementation and as a function of the abstract aspects of the relation between CS and US. Among a range of other findings, EC effects were stronger for high than for low contingency awareness, for supraliminal than for subliminal US presentation, for postacquisition than for postextinction effects, and for self-report than for implicit measures. These findings are discussed with regard to the procedural boundary conditions of EC and theoretical accounts about the mental processes underlying EC. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Signals of threat do not capture, but prioritize, attention: A conditioning approach.

Research suggests that threatening information captures attention more rapidly than neutral information. However, in most studies threat stimuli differ perceptually from neutral stimuli and are instrumental to perform the task, leaving the question unanswered whether threat is sufficient to capture attention. In experiment 1, we designed a visual search task with stimuli of equal salience (colored circles) that have the potential to lead to efficient search (10 ms/item). In experiment 2, one of the colors (conditioned stimulus, CS+) was made threatening by means of fear conditioning. Participants responded to a target presented in one of the circles. Overall, the search was faster on congruent trials (where the target was presented in the CS+) than on baseline trials (where the CS + was absent). Furthermore, the search was slower on incongruent trials (where the target was presented in another color than the CS+) than on baseline trials. The search on congruent trials was affected by set size (90 ms/item), but to a lesser extent than on baseline trials (105 ms/item). We conclude that threat prioritizes, but does not capture attention. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Avoidance and confrontation of painful, back-straining movements in chronic back pain patients

Avoidance of painful activities has been proposed to be an important risk factor for the initiation and maintenance of chronic low back suffering, whereas exposure to these activities has been suggested to be beneficial for recovery. In a cross-sectional study, the differences between chronic patients with avoidant and confrontational styles were investigated using self-report measures and a behavioral test. Participants were first classified as avoiders or confronters. In comparison with confronters, avoiders reported greater frequency and duration of pain, higher fear of pain and injury, more disability in daily living, and more attention to back sensations. Finally, avoiders reported more fear of (re)injury during the behavioral test and had a worse performance than confronters. The results suggest a close link between the fear of pain/(re)injury on one hand and avoidance behavior and physical deconditioning on the other hand.     

Neither extended sequential nor simultaneous feature positive training result in modulation of evaluative flavor-flavor conditioning in humans

Transgenic animals are new and important models for the study of candidate genes in hypertension research as well as in other fields of medicine. For detailed genetic characterization of the transgenic animals, and to account for the symptoms arising from the insertion of transgenes in the genome, it is essential to identify these insertion sites. In this study, the insertion sites of the transgenes of candidate genes for hypertension were identified by fluorescence in situ hybridization (FISH) after G-banding of the chromosomes in transgenic rats and mice. This technique combines high resolution G-banding and fluorescence in situ hybridization for the mapping of four different candidate genes in six different transgenic rats as well as three different mouse transgenic lines. The presented results will help to draw conclusions about the influence of the respective integration site on transgene expression.     

Imidazolium-Based Stabilization of Aqueous Multiwall Carbon Nanotube Dispersions

Imidazolium bromide, an ionic liquid surfactant acrylate, as well as its homopolymer and various copolymers are demonstrated to be superior dispersing aids for preparing aqueous multiwall carbon nanotube (MWCNT) dispersions. We demonstrate apparent complete exfoliation in water with extinction coefficients at 500 nm of about 60 cm² mg⁻¹ of MWCNT dispersed, a new lower bound and the highest reported extinction to date. The efficacy or efficiency of dispersion (activated by ultrasonication) is examined in terms of a quotient of extinction and weight ratio of the active monomer and MWCNT. A rank ordering of the results obtained for seven stabilizers based on the same imidazolium bromide monomer provides insights into roles of π-overlap adsorption onto MWCNT surfaces and how hydrogel properties of some of these polymers provide stability in water at higher concentrations than previously considered feasible for surfactant-stabilized and polymer-stabilized MWCNT dispersions. Simple nanocomposite film formation is demonstrated by casting and thermal diffusivity and electrical conductivity properties are examined.     

Piezoelectric inkjet printing of medical adhesives and sealants

Piezoelectric inkjet printing is a noncontact process that enables microscale processing of biological materials. In this research summary, the use of piezoelectric inkjet printing for patterning medical adhesives and sealants, including a two-component polyethylene glycol hydrogel-based medical sealant, an N-butyl cyanoacrylate tissue adhesive, and a mussel adhesive protein biological adhesive, is described The effect of Fe(III) on mussel adhesive protein structure was evaluated by means of atomic force microscopy. The ability to process microscale patterns of medical sealants and adhesives will provide an improvement in tissue joining, including enhanced tissue integrity, reduced bond lines, and decreased adhesive toxicity. Piezoelectric inkjet deposition of medical adhesives and sealants may be used in wound closure, fracture fixation, and microscale vascular surgery.     

Extinction in fear conditioning: effects on startle modulation and evaluative self-reports

gamma-Hydroxybutyric acid (GHB) is unfamiliar to many physicians in the United States but enjoys clinical use elsewhere for applications in resuscitation, anesthesia, and addiction therapy. Use within the United States is restricted to Food and Drug Administration-approved clinical trials for treatment of narcolepsy. Recently illicit use of GHB has emerged within the United States where it is distributed for purported euphoric and "fat-burning" metabolic effects. Clinical effects can be severe, progressing rapidly to respiratory arrest and death. We provide an updated comprehensive review of the literature with particular emphasis on toxicology, including GHB pharmacodynamics, clinical effects, and suggestions for overdose management. Recommended management of acute GHB intoxication includes prevention of aspiration, use of atropine for persistent symptomatic bradycardia, consideration of neostigmine as a reversal agent, and treatment for coingested substances. Emergency physicians are urged to become familiar with GHB because of its potential for severe morbidity as well as its potential use as a future resuscitative agent.     

Mood-Congruent Attentional Bias in Dysphoria: Maintained Attention to and Impaired Disengagement From Negative Information.

Attentional bias to negative information has been proposed to be a cognitive vulnerability factor for the development of depression. In 2 experiments, the authors examined mood-congruent attentional bias in dysphoria. In both experiments, dysphoric and nondysphoric participants performed an attentional task with negative, positive, and neutral word cues preceding a target. Targets appeared either at the same or at the opposite location of the cue. Overall, results indicate that dysphoric participants show maintained attention for negative words at longer stimulus presentations, which is probably caused by impaired attentional disengagement from negative words. Furthermore, nondysphoric participants maintain their attention more strongly to positive words. These results are discussed in relation to recent developments in the pathogenesis and treatment of depression. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Attention for emotional faces under restricted awareness revisited: Do emotional faces automatically attract attention?

Theoretical models of attention for affective information have assigned a special status to the cognitive processing of emotional facial expressions. One specific claim in this regard is that emotional faces automatically attract visual attention. In three experiments, the authors investigated attentional cueing by angry, happy, and neutral facial expressions that were presented under conditions of limited awareness. In these experiments, facial expressions were presented in a masked (14 ms or 34 ms, masked by a neutral face) and unmasked fashion (34 ms or 100 ms). Compared with trials containing neutral cues, delayed responding was found on trials with emotional cues in the unmasked, 100-ms condition, suggesting stronger allocation of cognitive resources to emotional faces. However, in both masked and unmasked conditions, the hypothesized cueing of visual attention to the location of emotional facial expression was not found. In contrary, attentional cueing by emotional faces was less strong compared with neutral faces in the unmasked, 100-ms condition. These data suggest that briefly presented emotional faces influence cognitive processing but do not automatically capture visual attention. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A 100-kHz to 20-MHz Reconfigurable Power-Linearity Optimized $G_m$–$C$ Biquad in 0.13-$mu$ m CMOS

Fully reconfigurable transceivers are required to answer the low-power high flexibility demand of future mobile applications. This paper presents a fully reconfigurable G_m-C biquadratic low-pass filter which offers a large range of both frequency and performance flexibility. First, a design approach is proposed focusing on linearity properties by extending Volterra analysis from circuit to architectural level in order to optimize the filters performance. Secondly, a novel switching technique is discussed that allows a bandwidth tuning over more than two orders of magnitude starting from 100 kHz up to 20 MHz and which uses only gate transistor capacitance. Fundamental to this technique is that the power consumption can be traded with the desired performance. Furthermore, the quality factor, noise level and linearity are all programmable over a very wide range. The biquad is processed in a 0.13-mum CMOS technology and operates at different supply voltages down to less than 0.8 V. For a 1.2-V supply, the filter consumes between 103 muA (100 kHz) and 11.85 mA (20 MHz) for a low noise setting around 25 to 35 muVrms integrated over the filter bandwidth achieving an third-order intermodulation intercept point of 10 dBVp.