Neuronal correlates of three attentional strategies during affective picture processing: an fMRI study

This functional magnetic resonance imaging (fMRI) study directly compared the neurocircuitry involved in three different attentional strategies during affective picture processing. We exposed 40 participants (20 men, 20 women) to images depicting dental treatment, as well as neutral scenes. They were asked to do one of three tasks while watching the same pictures: directing their attention toward a foreground object within the picture (distraction), classifying whether the image showed dental treatment, or deciding whether the scene elicited fear of pain (introspection). The participants performed the distraction and classification task with high accuracy and rated only 11 % of the dental treatment pictures as pain relevant. Introspection was associated with increased activation of the dorsomedial prefrontal cortex (DMPFC), relative to the two other conditions. Since the dental, relative to the neutral, pictures elicited enhanced DMPFC activation across all conditions, this underlines the role of this brain region for the assignment, as well as self-reference, of affective meaning. Moreover, self-reported dental anxiety was positively correlated with activation of a pain modulatory network (DMPFC, basal ganglia) when the participants focused on the pain relevance of the dental treatment cues. For future studies, it seems promising to study a high-anxious group or even patients afflicted with dental phobia.     

Something in the way she moves—movement trajectories reveal dynamics of self-control

This study examined the dynamic impact of self-control conflict on action execution. We reasoned that the tug-of-war between antagonistic action tendencies is not ultimately solved before movement initiation but leaks into action execution. To this end, we measured mouse trajectories to quantify the dynamic competition between initial temptations and the struggle to overcome them. Participants moved the mouse cursor from a start location to one of two targets. Each target represented a gain or a loss of points. Although participants earned points on the majority of the trials, they also had to make movements to the loss target on some trials to prevent an even higher loss. Two experiments found that movement trajectories on these loss trials deviate toward the tempting stimulus: The way we move reveals self-control conflicts that have not been resolved prior to action execution.     

Human trace fear conditioning: right-lateralized cortical activity supports trace-interval processes

Pavlovian conditioning requires the convergence and simultaneous activation of neural circuitry that supports conditioned stimulus (CS) and unconditioned stimulus (US) processes. However, in trace conditioning, the CS and US are separated by a period of time called the trace interval, and thus do not overlap. Therefore, determining brain regions that support associative learning by maintaining a CS representation during the trace interval is an important issue for conditioning research. Prior functional magnetic resonance imaging (fMRI) research has identified brain regions that support trace-conditioning processes. However, relatively little is known about whether this activity is specific to the trace CS, the trace interval, or both periods of time. The present study was designed to disentangle the hemodynamic response produced by the trace CS from that associated with the trace interval, in order to identify learning-related activation during these distinct components of a trace-conditioning trial. Trace-conditioned activity was observed within dorsomedial prefrontal cortex (PFC), dorsolateral PFC, insula, inferior parietal lobule (IPL), and posterior cingulate (PCC). Each of these regions showed learning-related activity during the trace CS, while trace-interval activity was only observed within a subset of these areas (i.e., dorsomedial PFC, PCC, right dorsolateral PFC, right IPL, right superior/middle temporal gyrus, and bilateral insula). Trace-interval activity was greater in right than in left dorsolateral PFC, IPL, and superior/middle temporal gyrus. These findings indicate that components of the prefrontal, cingulate, insular, and parietal cortices support trace-interval processes, as well as suggesting that a right-lateralized fronto-parietal circuit may play a unique role in trace conditioning.     

Irradiation-induced dissociation of an a ⟨100⟩ edge dislocation in SrTiO3

We report the dissociation of an a?100? dislocation core in SrTiO₃ into two (a/2)?100? partial cores during electron-beam irradiation in a high-voltage transmission electron microscope. The partial separation is approximately 1?nm. Based on the forces acting between the partials, a dissociation mechanism is proposed which includes a combination of climb and glide processes.     

Association between Inhibitory Control Capacity and Body Weight in Overweight and Obese Children and Adolescents: Dependence on Age and Inhibitory Control Component

It has been assumed that overweight individuals show weak inhibitory control capacity leading to a failure to resist external cues for palatable food and that this deficit underlies the recently reported empirical association between obesity and attention deficit/hyperactivity disorder (ADHD). In childhood and adolescence, empirical research on this issue is scarce. Here, the hypothesis is tested that high body weight is associated with weak inhibitory control performance and that this association is moderated by age.

The sample included 177 overweight and obese children and adolescents (BMI: M = 29.2, SD = 4.33; BMI-SDS: M = 2.45, SD = 0.43) between 8 and 15 years. Inhibitory control was assessed by a Go/No-Go task and an Interference Task. A principal component analysis yielded two components: impulsivity (fast but invalid responses) and inattention (highly variable reaction times).

While controlling for age, gender, and maternal education level, we found that more obese children/adolescents showed more inattention. As indicated by a significant interaction effect, exclusively at younger ages, high impulsivity was associated with high body weight.

The results thus confirm a link between low inhibitory control capacity and high body weight and might point to a developmental period with heightened significance of impulsivity for weight gain.     

Selecting Predictor Subsets: Considering validity and adverse impact

The paper proposes a procedure for designing Pareto‐optimal selection systems considering validity, adverse impact and constraints on the number of predictors from a larger subset that can be included in an operational selection system. The procedure determines Pareto‐optimal composites of a given maximum size thereby solving the dual task of identifying the predictors that will be included in the reduced set and determining the weights with which the retained predictors will be combined to the composite predictor. Compared with earlier proposals, the simultaneous consideration of both tasks makes it possible to combine several strategies for reducing adverse impact in a single procedure. In particular, the present approach allows integrating (a) investigating a large number of possible predictors (such as multitest battery of ability tests, or a collection of ability and nonability measures); (b) explicit predictor weighting within feasible test procedures of a given limited size.     

Spatial correspondence between onsets and offsets of stimuli and responses

The Simon effect denotes faster responses when the task-irrelevant stimulus position corresponds to response position than when it does not. A common explanation is that a spatial stimulus code is formed automatically and activates a spatially corresponding response code. Previous research on stimulus–response (S–R) compatibility has focused on the ability to initiate movements to stimulus onsets. The present study investigates spatial-compatibility effects (i.e., the Simon effect) in the ability to initiate and to terminate actions both to stimulus onsets and to stimulus offsets. There were four major results. Firstly, offset stimuli produced normal Simon effects suggesting that stimulus offsets can automatically produce spatial codes. Secondly, onset stimuli produced larger Simon effects than offset stimuli, which is consistent with the attention-shift account of spatial coding. Thirdly, Simon effects were also observed in action termination. Fourthly, Simon effects in action initiation and in action termination were of similar size.     

Limited transfer of subliminal response priming to novel stimulus orientations and identities

Recently, priming effects of unconscious stimuli that were never presented as targets have been taken as evidence for the processing of the stimuli's semantic categories. The present study explored the necessary conditions for a transfer of priming to novel primes. Stimuli were digits and letters which were presented in various viewer-related orientations (upright, horizontal, inverted). The transfer of priming to novel stimulus orientations and identities was remarkably limited: in Experiment 1, in which all conscious targets stood upright, no transfer to unconscious primes in a non-target orientation was found. Experiment 2, in which primes were presented without masks, ruled out the possibility that primes were presented too short to allow congruency effects. In Experiments 3 and 4, in which all targets were presented upside down, priming transferred to upright stimuli with target identities but neither to horizontal stimuli nor to stimuli with novel identities. We suggest that whether a transfer of priming to unpracticed stimuli occurs or not depends on observers' expectations of specific stimulus exemplars.     

Negative congruency effects: a test of the inhibition account

Masked priming experiments occasionally revealed surprising effects: Participants responded slower for congruent compared to incongruent primes. This negative congruency effect (NCE) was ascribed to inhibition of prime-induced activation [Eimer, M., & Schlaghecken, F. (2003). Response faciliation and inhibition in subliminal priming. Biological Psychology, 64, 7-26.] that sets in if the prime activation is sufficiently strong. The current study tests this assumption by implementing manipulations designed to vary the amount of prime-induced activation in three experiments. In Experiments 1 and 3, NCEs were observed despite reduced prime-induced activation. Experiment 2 revealed no NCE with at least similar prime strength. Thus, the amount of prime activation did not predict whether or not NCEs occurred. The findings are discussed with regard to the inhibition account and the recently proposed account of mask-induced activation [cf. Lleras, A., & Enns, J. T. (2004). Negative compatibility or object updating? A cautionary tale of mask-dependent priming. Journal of Experimental Psychology: General, 133, 475-493; Verleger, R., Jaskowski, P., Aydemir, A., van der Lubbe, R. H. J., & Groen, M. (2004). Qualitative differences between conscious and nonconscious processing? On inverse priming induced by masked arrows. Journal of Experimental Psychology: General, 133, 494-515].