Post-training intrahippocampal inhibition of class I histone deacetylases enhances long-term object-location memory

Long-term memory formation involves covalent modification of the histone proteins that package DNA. Reducing histone acetylation by mutating histone acetyltransferases impairs long-term memory, and enhancing histone acetylation by inhibiting histone deacetylases (HDACs) improves long-term memory. Previous studies using HDAC inhibitors to enhance long-term memory have focused on the fear-conditioning task using broad-spectrum HDAC inhibitors. We have found that post-training intrahippocampal administration of the broad-spectrum HDAC inhibitor trichostatin A (TSA) or the class I HDAC-selective inhibitor MS275 enhances long-term object-location memory, supporting a role for class I HDACs in the enhancement of hippocampus-dependent memory induced by HDAC inhibition.     

Development of a metabolic equation for the NuStep recumbent stepper in older adults

The purpose of this study was to develop an accurate metabolic equation for estimating steady-state oxygen consumption (VO2) during submaximal NuStep exercise. Adults (N = 40; M age = 64.0 yr., SD = 6.5; M height = 170.1 cm, SD = 9.1; M weight = 85.7 kg, SD = 19.9) performed two randomized testing sessions. Each session consisted of six stages with combinations of four workloads (1, 3, 5, and 7) at 3 cadences (60, 80, and 100 steps/min.). Multiple regression analysis to predict steady-state VO2 from NuStep workload (W), NuStep steps/min., and subject body mass resulted in the following model (R2 = .73): Steady-state VO2 = 3.5 + 0.016 (W* steps/min.) + 0.092 (steps/min.) - 0.053 (weight). The standard error of the estimate and total error for the prediction of steady-state VO2 under all NuStep workload conditions were 2.3 mL/kg/min. and 2.4 mL/kg/ min., respectively. The standard error of the estimate and total error values are similar to those previously reported in the literature regarding the accuracy of metabolic equations for other exercise modalities. These findings support the use of the equation developed to predict steady-state VO2 for NuStep exercise in older adult clientele.     

Selective inhibition in children with attention-deficit hyperactivity disorder off and on stimulant medication

Selective inhibition requires discrimination between auditory signals and is assessed using a modification of the stop-signal task. Selective inhibition was assessed in a group of 59 clinic-referred, DSM-IV-diagnosed children with attention-deficit hyperactivity disorder (ADHD) and compared to that of a community sample of 59 children. Methylphenidate (MPH) effects on selective inhibition were assessed in a subset of the ADHD sample that participated in an acute, randomized, placebo-controlled, crossover trial with 3 fixed doses of MPH. Children with ADHD performed more poorly than controls on the majority of selective stop-signal task parameters: they exhibited more anticipatory (invalid) responses, with less accurate and more variable responses on the response execution task, as well as a slower selective inhibition process. MPH improved speed of both inhibition and response execution processes; it also reduced variability of response execution and decreased nonselective inhibition. On the one hand, findings are consistent with purported inhibition deficit in ADHD, but on the other hand, suggest that neither the impairment itself, nor MPH effects, were restricted to inhibition.     

Validity of specific motor skills in predicting table-tennis performance in novice players

An experiment assessed whether novice table-tennis players' ball-balancing and bouncing skills could predict their performances after a semester of being coached. A pretest-posttest design was used to test this hypothesis with 82 male and 77 female physical education students who initially performed the skills and subsequently participated in a round-robin tournament. Moderate negative but significant (p<.01) Spearman rank-order correlation coefficients were obtained between some of the ball control skills scores and overall ranking in the table-tennis tournament.     

Environmental enrichment modifies the PKA-dependence of hippocampal LTP and improves hippocampus-dependent memory

cAMP-dependent protein kinase (PKA) is critical for the expression of some forms of long-term potentiation (LTP) in area CA1 of the mouse hippocampus and for hippocampus-dependent memory. Exposure to spatially enriched environments can modify LTP and improve behavioral memory in rodents, but the molecular bases for the enhanced memory performance seen in enriched animals are undefined. We tested the hypothesis that exposure to a spatially enriched environment may alter the PKA dependence of hippocampal LTP. Hippocampal slices from enriched mice showed enhanced LTP following a single burst of 100-Hz stimulation in the Schaffer collateral pathway of area CA1. In slices from nonenriched mice, this single-burst form of LTP was less robust and was unaffected by Rp-cAMPS, an inhibitor of PKA. In contrast, the enhanced LTP in enriched mice was attenuated by Rp-cAMPS. Enriched slices expressed greater forskolin-induced, cAMP-dependent synaptic facilitation than did slices from nonenriched mice. Enriched mice showed improved memory for contextual fear conditioning, whereas memory for cued fear conditioning was unaffected following enrichment. Our data indicate that exposure of mice to spatial enrichment alters the PKA dependence of LTP and enhances one type of hippocampus-dependent memory. Environmental enrichment can transform the pharmacological profile of hippocampal LTP, possibly by altering the threshold for activity-dependent recruitment of the cAMP-PKA signaling pathway following electrical and chemical stimulation. We suggest that experience-dependent plasticity of the PKA dependence of hippocampal LTP may be important for regulating the efficacy of hippocampus-based memory.     

Global Zimbabweans: Diaspora Engagement and Disengagement

Since 2000, migration from crisis-ridden Zimbabwe has led to almost one million people leaving the country. The majority migrate to neighbouring South Africa and Botswana, and most of the research on the Zimbabwean diaspora to date has focused on South Africa and the UK. However, the Zimbabwean diaspora is now truly global in its distribution. This paper argues that more attention should therefore be paid to Zimbabweans in other jurisdictions in the Global South and North. Zimbabweans began migrating to Canada in increasing numbers after 2000, most as refugees but also as immigrants and students. Based on a survey of the Zimbabwean diaspora in Canada, this paper focuses on their migration history, demographic characteristics and backward linkages with Zimbabwe. Given the interest in diaspora engagement in the global migration and development literature, it is important to understand the nature of these linkages in order to assess the potential for diaspora involvement in Zimbabwean development. The paper argues that under current economic and political conditions in Zimbabwe, this potential remains weak.     

Judging and actualizing intrapersonal and interpersonal affordances

The current study investigated the perception of intrapersonal, interpersonal, and tool-based grasping possibilities. In Experiment 1, participants judged whether they would grasp planks of wood-presented in ascending, descending, and random orders of length-using one hand (1H), two hands (2H), or with a tool that extended their reach (TH). In Experiment 2, participants physically grasped the planks using 1H, 2H, or TH. In Experiments 3 and 4, the choice of TH was replaced with a choice of grasping the planks with another person (2P). The results showed that presentation order influenced the participants' behavior differently in the judgment and action experiments. The same behavioral patterns, however, were observed when participants switched between 1H and 2H, 2H and TH, and 2H and 2P grasping. The point at which participants judged they would switch between the different modes of grasping, as well as the point at which participants physically switched between the grasping modes, occurred at similar action-scaled ratios. The equivalence of perceiving intrapersonal and interpersonal affordances is discussed.     

Rorschach Comprehensive System data for a sample of 309 adult nonpatients from Portugal

Three hundred and nine nonpatient adults, evenly distributed according to sex, age, educational level, and residence, took part in the Rorschach test study carried out in Portugal. The sample was drawn from selected regions of the country and was balanced for population density in urban and rural areas. Test administration was controlled through the services of psychologists familiar with the Rorschach Comprehensive System (CS; Exner, 1993). Results indicate that, in Portugal (Pires, 2000), level of education is the variable that seems to have the largest effect on Rorschach responding.     

Lefties are still a little shorter

Heights and weights of right- and left-handed major league baseball pitchers (N=5780) were analyzed, adjusted for birth year. Right-handed pitchers were about 1.6 cm taller and 1.9 kg heavier than left-handed pitchers. The results corroborated other studies and suggest body size is related to handedness, although the average difference in height between right- and left-handed pitchers was very small.