Hyperhomocysteinemia,MMPs and Cochlear Function: A Short Review

Hyperhomocysteinemia (HHCY) has been demonstrated to affect cochlear microvasculature as well as cochlear epithelial cells directly, with a resultant alteration of the expression of matrix metalloproteinases (MMPs) and their inhibitors, tissue inhibitors of metalloproteinases (TIMPs). Hence, ascertaining the optimum concentration of MMPs and TIMPs in the cochlea could help to inhibit hearing loss due to HHCY by the administration of appropriate MMP inhibitors, Since infections/inflammations as well as ototoxic antibiotics have a similar mechanism of otic pathology, the cochlear damage they cause could also be similarly prevented.     

Urban Youth's Perspectives on Flash Mobs

Flash mobs are new, emerging, and evolving social phenomena that have recently been associated with youth violence in the US cities. The current study explores how youth understand flash mobs through focus groups conducted in Kansas City, Missouri (a site of violent youth flash mobs). Results indicate that youth have varying familiarity with flash mobs and define them in different ways; that youth perceive youth boredom to be the most frequent cause of problems with flash mobs; that youth connect ongoing social disorder with the violence associated with flash mobs; and that while social media are facilitators of flash mobs, flash mobs have their roots in youth activities that have been going on for generations (e.g., hanging out in groups and cruising). Results illustrate the importance of conducting formative research with youth, particularly about emergent phenomena, when developing interventions and communication campaigns aimed at reducing youth violence.     

Retrieval practice after multiple context changes,but not long retention intervals,reduces the impact of a final context change on instrumental behavior

Recent evidence from this laboratory suggests that a context switch after operant learning consistently results in a decrement in responding. One way to reduce this decrement is to train the response in multiple contexts. One interpretation of this result, rooted in stimulus sampling theory, is that conditioning of a greater number of common stimulus elements arising from more contexts causes better generalization to new contexts. An alternative explanation is that each change of context causes more effortful retrieval, and practice involving effortful retrieval results in learning that is better able to transfer to new situations. The current experiments were designed to differentiate between these two explanations for the first time in an animal learning and memory task. Experiment 1 demonstrated that the detrimental impact of a context change on an instrumental nose-poking response can be reduced by training the response in multiple contexts. Experiment 2 then found that a training procedure which inserted extended retention intervals between successive training sessions did not reduce the detrimental impact of a final context change. This occurred even though the inserted retention intervals had a detrimental impact on responding (and, thus, presumably retrieval) similar to the effect that context switches had in Experiment 1. Together, the results suggest that effortful retrieval practice may not be sufficient to reduce the negative impact of a context change on instrumental behavior. A common elements explanation which supposes that physical and temporal contextual cues do not overlap may account for the findings more readily.     

Validity and feasibility of an obstacle course to assess fundamental movement skills in a pre-school setting

Failure to master age-appropriate fundamental movement skills (FMS) at a young age can limit motor skill competence affecting health. Assessments often have issues with feasibility and implementation in a field setting. As such, the purpose of this study was to investigate the validity and feasibility of the Athletic Skills Track (AST), in a pre-school setting. For the validation study sixty-five 3–6 year old children (25 boys and 40 girls) from five pre-schools across Adelaide, Australia participated. Correlations and linear regression analysis (adjusted for age and gender) were used to investigate the association between the time to complete the AST and the raw score of the Test of Gross Motor Development 2 (TGMD-2). For the feasibility study pre-school staff completed a semi-structured interview regarding the feasibility of the AST. The AST took less than a minute per child and the TGMD-2 around 20 minutes for two children. There was a strong negative correlation (r = ?0.63, p < 0.01) between the AST scores and the TGMD-2 scores. All five staff reported strengths of the AST to be its short administration time, setup and appropriateness. These results suggest that the AST could be a feasible and valid method of FMS assessment in Australian pre-schools.     

Contextual control of operant behavior: evidence for hierarchical associations in instrumental learning

Recent research has suggested that operant responses can be weakened when they are tested in new contexts. The present experiment was therefore designed to test whether animals can learn a context–(R–O) relation. Rats were given training sessions in context A, in which one response (R1; lever pressing or chain pulling) produced one outcome (O1) and another response (R2; chain pulling or lever pressing) produced another outcome (O2) on variable interval reinforcement schedules. These sessions were intermixed with training in context B, where R1 now produced O2 and R2 produced O1. Given the arrangement, it was possible for the animal to learn two distinct R–O associations in each specific context. To test for them, rats were then given aversion conditioning with O2 by pairing its presentation with lithium-chloride-induced illness. Following the aversion conditioning, the rats were given an extinction test with both R1 and R2 available in each context. During testing, rats showed a selective suppression in each context of the response that had been paired with the reinforcer subsequently associated with illness. Rats could not have performed this way without knowledge of the R–O associations in effect in each specific context, lending support to the hypothesis that rats learn context–(R–O) associations. However, despite a complete aversion to O2, responding was not completely suppressed, leaving the possibility open that rats form context–R associations in addition to context–(R–O) associations.