Plasticity associated with escalated operant ethanol self-administration during acute withdrawal in ethanol-dependent rats requires intact matrix metalloproteinase systems

Repeated cycles of ethanol intoxication and withdrawal associated with dependence induce neuroadaptations in a variety of brain systems. Withdrawal-induced negative emotional states can be ameliorated by ethanol consumption; a learned process termed negative reinforcement. Accordingly, a dependence-induced phenotype is escalated ethanol self-administration. Matrix metalloproteinases (MMPs) are proteolytic enzymes which degrade the extracellular matrix to allow for synaptic reorganization and plasticity. To test the hypothesis that an intact MMP system is required for animals to learn about the negative reinforcing effects of ethanol and display escalated self-administration during acute withdrawal when ethanol-dependent, male Wistar rats were trained to self-administer ethanol and then assigned to either acute or chronic MMP inhibition treatment groups. The chronic treatment group received intracerebroventricular (ICV) infusions of the broad spectrum MMP inhibitor FN-439 or artificial cerebrospinal fluid (aCSF) via osmotic minipumps during a 1 month ethanol dependence induction period and subsequent post-dependence induction self-administration sessions that occurred during acute withdrawal. The acute treatment group only received ICV FN-439 or aCSF on the day of self-administration sessions following dependence induction during acute withdrawal. The results showed that inhibition of MMPs attenuated escalated ethanol self-administration following chronic and acute exposure conditions. Furthermore, once learning (i.e., plasticity) had occurred, MMP inhibition had no impact on escalated response patterns and animals previously subjected to MMP inhibition that did not escalate evidenced normal escalations in operant ethanol self-administration once FN-439 treatments were terminated. Thus, the present data identified that an intact MMP system is required for the escalated responding that occurs during acute withdrawal in dependent animals and implicate such escalation as a learned response.     

Is school bullying really on the rise?

Whether bullying in schools is increasing, as is widely believed, was investigated drawing upon empirical studies undertaken in a wide range of countries in which findings had been published describing its prevalence at different points in time between 1990 and 2009. Results do not support the view that reported bullying in general has increased during this period; in fact, a significant decrease in bullying has been reported in many countries. However, there are some indications that cyber bullying, as opposed to traditional bullying, has increased, at least during some of this period. The reported decreases in the prevalence of school bullying are consistent with reports of significant but small reductions in peer victimisation following the implementation of anti-bullying programs in schools world-wide.     

Age and gender comparisons of driving while sleepy: Behaviours and risk perceptions

To assist road safety professionals in developing effective strategies to combat the risk associated with driving while fatigued, a survey was administered to 1000 Australian drivers. Participants reported their past behaviours in regards to driving while sleepy and their perceptions of risk associated with driving fatigued as compared to speeding and driving under the influence of alcohol. Although participants appeared to be aware of the substantial risk associated with driving while sleepy, many drivers reported that they frequently drive when sleepy. Age and gender comparisons, revealed that risk taking behaviour in regards to driving while sleepy is occurring across all age groups and in both male and female drivers. Overall young to middle age drivers and male drivers reported the highest frequency of driving while sleepy and reported the lowest perceived personal risk in regards to driving while sleepy.     

Anxiety, movement kinematics, and visual attention in elite-level performers

We tested the predictions of Attentional Control Theory (ACT) by examining the effect of anxiety on attention control and the subsequent influence on both performance effectiveness and performance efficiency within a perceptual-motor context. A sample (N = 16) of elite shotgun shooters was tested under counterbalanced low (practice) and high (competition) anxiety conditions. A head-mounted, corneal reflection system allowed point of gaze to be calculated in relation to the scene, while motion of the gun was evaluated using markers placed on the barrel which were captured by two stationary cameras and analyzed using optical tracking software. The quiet eye (QE) duration and onset were analyzed along with gun barrel displacement and variability; performance outcome scores (successful vs. unsuccessful) were also recorded. QE (Vickers, 1996) is defined as the final fixation or tracking gaze that is located on a specific location/object in the visual display for a minimum of 100 ms. Longer QE durations have been linked to successful performance in previous research involving aiming tasks. Participants demonstrated shorter quiet eye durations, and less efficient gun motion, along with a decreased performance outcome (fewer successful trials) under high compared with low anxiety conditions. The data support the predictions of ACT with anxiety disrupting control processes such that goal-directed attention was compromised, leading to a significant impairment in performance effectiveness.     

The effects of valence and arousal on the emotional modulation of time perception: evidence for multiple stages of processing

Previous research has demonstrated that both emotional valence and arousal can influence the subjective experience of time. The current research extends this work by (1) identifying how quickly this emotional modulation of time perception can occur and (2) examining whether valence and arousal have different effects at different stages of perception. These questions were addressed using a temporal bisection task. In each block of this task, participants are trained to distinguish between two different exposure durations. Participants are then shown stimuli presented at a number of durations that fall between the two learned times, and are asked to indicate whether the test stimulus was closer in duration to the shorter or longer learned item. In the current study, participants completed blocks of trials in which the durations were "Short" (100-300 ms) or "Long" (400-1600 ms). Stimuli consisted of neutral photographs as well as four categories of emotional images: high-arousal negative, high-arousal positive, low-arousal negative, and low-arousal positive. In Short blocks, arousing and nonarousing negative images were judged to have been shown for shorter durations than they actually were (i.e., the duration was underestimated); this effect occurred at durations as brief as 133 ms. In Long blocks, the display time for highly arousing negative items was overestimated, whereas durations were underestimated for highly arousing positive items and less arousing negative items. These data suggest that arousal and valence have different effects at different stages of perception, possibly due to the different neural structures involved at each stage of the emotional modulation of time perception.     

Attentional bias to emotional stimuli is altered during moderate- but not high-intensity exercise

Little is known regarding how attention to emotional stimuli is affected during simultaneously performed exercise. Attentional biases to emotional face stimuli were assessed in 34 college students (17 women) using the dot-probe task during counterbalanced conditions of moderate- (heart rate at 45% peak oxygen consumption) and high-intensity exercise (heart rate at 80% peak oxygen consumption) compared with seated rest. The dot-probe task consisted of 1 emotional face (pleasant or unpleasant) paired with a neutral face for 1,000 ms; 256 trials (128 trials for each valence) were presented during each condition. Each condition lasted approximately 10 min. Participants were instructed to perform each trial of the dot-probe task as quickly and accurately as possible during the exercise and rest conditions. During moderate-intensity exercise, participants exhibited significantly greater attentional bias scores to pleasant compared with unpleasant faces (p < .01), whereas attentional bias scores to emotional faces did not differ at rest or during high-intensity exercise (p > .05). In addition, the attentional bias to unpleasant faces was significantly reduced during moderate-intensity exercise compared with that during rest (p < .05). These results provide behavioral evidence that during exercise at a moderate intensity, there is a shift in attention allocation toward pleasant emotional stimuli and away from unpleasant emotional stimuli. Future work is needed to determine whether acute exercise may be an effective treatment approach to reduce negative bias or enhance positive bias in individuals diagnosed with mood or anxiety disorders, or whether attentional bias during exercise predicts adherence to exercise.     

Don't sit so close to me: unconsciously elicited affect automatically provokes social avoidance

Behavior may be automatically prompted by cues in our social environment. Previous research has focused on cognitive explanations for such effects. Here we hypothesize that affective processes are susceptible to similar automatic influences. We propose that exposure to groups stereotyped as dangerous or violent may provoke an anxiety response and, thus, a tendency to move away. In the present experiment, we subliminally exposed participants to images of such a group, and found that they displayed greater avoidance in a subsequent interaction. Critically, this effect was explained by their increased sensitivity to threat-related information. These findings demonstrate an affective mechanism responsible for nonconscious priming effects on interpersonal behavior.     

The multinomial model of prospective memory: validity of ongoing-task parameters

The objective of this research was to provide additional experimental validation of the multinomial processing tree (MPT) model of event-based prospective memory (Smith & Bayen, 2004). In particular, the parameters that measure trial-type detection in the ongoing task were examined. In three experiments with different response instructions, event-based prospective memory tasks were embedded in ongoing color-matching tasks. The results support the validity of the MPT model, that is, manipulations of ongoing-task difficulty affected the ongoing-task parameters of the MPT model, while leaving the estimates for the prospective and the retrospective components of prospective memory unaffected.     

Effects of cell-phone and text-message distractions on true and false recognition

This study examined the effects of electronic communication distractions, including cell-phone and texting demands, on true and false recognition, specifically semantically related words presented and not presented on a computer screen. Participants were presented with 24 Deese-Roediger-McDermott (DRM) lists while manipulating the concurrent presence or absence of cell-phone and text-message distractions during study. In the DRM paradigm, participants study lists of semantically related words (e.g., mother, crib, and diaper) linked to a non-presented critical lure (e.g., baby). After studying the lists of words, participants are then requested to recall or recognize previously presented words. Participants often not only demonstrate high remembrance for presented words (true memory: crib), but also recollection for non-presented words (false memory: baby). In the present study, true memory was highest when participants were not presented with any distraction tasks during study of DRM words, but poorer when they were required to complete a cell-phone conversation or text-message task during study. False recognition measures did not statistically vary across distraction conditions. Signal detection analyses showed that participants better discriminated true targets (list items presented during study) from true target controls (items presented during study only) when cell-phone or text-message distractions were absent than when they were present. Response bias did not vary significantly across distraction conditions, as there were no differences in the likelihood that a participant would claim an item as "old" (previously presented) rather than "new" (not previously presented). Results of this study are examined with respect to both activation monitoring and fuzzy trace theories.     

The impact of aerobic activity on cognitive function in older adults: A new synthesis based on the concept of executive control

Numerous reaction time studies have suggested that age-related declines in cognitive function might be ameliorated by lifestyles involving aerobic activity or by interventionist programmes of aerobic exercise. These studies are far from conclusive, however, reflecting a failure to factor out cognitive from sensory and motor processes. Following a critical review of the literature, we report on recent developments that differentiate cognitive processes involving executive vs non-executive control, the former being associated with frontal lobe function. Three key studies suggest that aerobic exercise primarily improves executive control.