Spatiotemporal variations of alpha and sigma band EEG in the waking-sleeping transition period

The aim of this study is to evaluate the spatiotemporal variation of alpha and sigma band EEGs during the waking-sleeping transition or hypnagogic period. Power and coherence from 7 EEG channels (Fp1, F7, Fz, C3, Pz, T5, O1) were studied using EEG records of the period of 5 min. before the onset of Stage 1 to 24 min. after the onset of Stage 1. The EEG spectra were computed for 4 frequency bands (alpha 1: 8.0-9.0 Hz, alpha 2: 9.5-11.0 Hz, alpha 3: 11.5-12.5 Hz, and sigma: 13.0-15.0 Hz). The power of alpha 1 and 2 bands initially started to decrease before the onset of Stage 1. Principal component analysis of the coherence yielded Generalized and Localized Components in each band. The Generalized Component was widespread across scalp areas, while the Localized Component was a restricted local area. The Generalized Components of alpha 1 and 2 bands reached stable levels of NREM sleep about 1 min. after the onset of Stage 1. The component of sigma band reached a stable level of NREM sleep about 0.6 min. before the onset of Stage 2, while the component of alpha 3 band reached a stable level of NREM sleep about 3.4 min. after the onset of Stage 2. These results suggest that the alpha-sigma band EEG structures during the waking-sleeping transition period may not be uniform across EEG bands and that the hypnagogic EEG changes may start before the onset of Stage 1 and continue for several minutes after the onset of Stage 2.     

Yielding and strain hardening in aluminium single-crystal foils subjected to tension and bending

A series of tensile and microbend tests were conducted on aluminium single-crystal foil specimens with different thicknesses ranging from 20 to 90?µm. Two different crystal orientations relative to the tensile direction were considered in the tests: one is an orientation that was excepted to activate at least four slip systems on four different slip planes, and the other is an orientation that was expected to activate only a single-slip system. In the tensile tests, typical size dependence of initial yield strength was observed. The microbend test method was extended to include a reversal of bending direction. Using the curves of bending moment normalized by the square of foil thickness versus surface strain, which were obtained from the reversed bending tests, the total amounts of strain hardening were divided into isotropic and kinematic hardening components. In the microbend tests, a pronounced size-dependent kinematic hardening behaviour was clearly observed; meanwhile, the amounts of isotropic hardening were very small, particularly for the single-slip orientation.     

Longitudinal relations among maternal behaviors, effortful control and young children's committed compliance

In a sample (n = 235) of 30-, 42-, and 54-month-olds, the relations among parenting, effortful control (EC), impulsivity, and children's committed compliance were examined. Parenting was assessed with mothers' observed sensitivity and warmth; EC was measured by mothers' and caregivers' reports, as well as a behavioral task; impulsivity was assessed by mothers' and caregivers' reports; and committed compliance was observed during a cleanup and prohibition task, as well as measured by adults' reports. Using path modeling, there was evidence that 30-month parenting predicted high EC and low impulsivity a year later when the stability of the outcomes was controlled, and there was evidence that 30- and 42-month EC, but not impulsivity, predicted higher committed compliance a year later, controlling for earlier levels of the outcomes. Moreover, 42-month EC predicted low impulsivity a year later. Fixed effects models, which are not biased by omitted time-invariant variables, also were conducted and showed that 30-month parenting still predicted EC a year later, and 42-month EC predicted later low impulsivity. Findings are discussed in terms of the importance of differentiating between effortful control and impulsivity and the potential mediating role of EC in the relations between parenting and children's committed compliance.     

Serum levels of brain-derived neurotrophic factor (BDNF), BDNF gene Val66Met polymorphism, or plasma catecholamine metabolites, and response to mirtazapine in Japanese patients with major depressive disorder (MDD)

Object We investigated an association between the polymorphism of brain-derived neurotrophic factor (BDNF) gene Val66Met and the response to mirtazapine in Japanese patients with major depressive disorder (MDD). We also examined mirtazapine's effects on the serum BDNF and plasma levels of catecholamine metabolites in these patients. METHODS: Eighty-four patients who met the DSM-IV-TR criteria for MDD were treated with only mirtazapine for 4 weeks. The BDNF Val66Met polymorphism was detected by direct sequencing in the region, and serum BDNF levels and plasma levels of catecholamine metabolites were measured by ELISA and HPLC-ECD, respectively. RESULTS: Mirtazapine treatment for 4 weeks significantly increased serum BDNF levels in the responders, whereas nonresponders showed significant decreases. No association was found between either of the two genotypes (Val/Val vs. Met-carriers) and the response to mirtazapine at T4 or the serum BDNF levels at T0. Mirtazapine did not alter the plasma levels of homovanillic acid (HVA) or 3-methoxy-4-hydroxyphenylglycol (MHPG). Discussion The dynamics of serum BDNF levels, but not plasma levels of HVA and MHPG, reflect the response to mirtazapine treatment; the BDNF Val66Met polymorphism in patients with depression is, however, associated with neither a particular response to mirtazapine treatment nor baseline serum BDNF levels. Conclusion Serum BDNF levels, but not plasma levels of HVA or MHPG, and BDNF Val66Met polymorphism are related to the mirtazapine response in MDD.     

Deliberate Self‐Harm in Adolescents Aged 12–18: A Cross‐Sectional Survey of 18,104 Students

Little is known about accurate prevalence and associated factors of deliberate self‐harm (DSH) among adolescents in Asian countries. In this study, the prevalence and associated factors of DSH among adolescents in Japan were examined. Data were derived from a cross‐sectional survey using an anonymous self‐report questionnaire and enrolling 8,620 adolescents aged 12–15 and 9,484 aged 15–18. DSH in the previous 12 months was reported by 3.3% (95% CI, 2.9–3.7) of junior and 4.3% (3.9%–4.7%) of senior high school respondents. The prevalence was more than four times as high among girls as among boys for both age groups. DSH was further strongly associated with having suicidal thoughts, having depression/anxiety symptoms, and having used recreational drugs. These associated factors were similar for both sexes and for both older and younger teenagers. A substantial minority of adolescents present with DSH, even among those aged 12–15. The prevalence of DSH in Japan was in the lower ranges of those reported for Western countries. The identified associated factors were not dissimilar from those reported in the West.     

Changes in Muscle Activity in Response to Assistive Force during Isometric Elbow Flexion

Abstract

This study investigated the muscle activity and force variability in response to perturbation of assistive force during isometric elbow flexion. Sixteen healthy right-handed young men (age: 22.0?±?1.1?years; height: 171.9?±?4.8?cm; weight 68.4?±?11.2?kg) were recruited and the muscle activity of biceps brachii and triceps brachii were assessed using surface electromyography. Workload force and assistive force applied on isometric elbow flexion significantly affected the changes in both biceps and triceps muscle activities. A higher assistive force was shown to result in reduced biceps muscle activity compared to the unassisted period. In contrast, the efficiency of the assistive force acting on the biceps decreased as the assistive force increased. In general, the force variability of the biceps muscle remained approximately the same at lower workload force conditions than that at higher workload force conditions. In conclusion, higher assistive force may not yield a higher performance efficiency in human-assistive force interaction.     

Do 5- and 6-Year-Old Children Attempt to Appear Fair to Others?

Abstract

Children come to prefer fair distributions at the age of 5 to 6?years. But do they actually want to be fair, or do they want to appear fair to others? In three conditions, an experimenter initially distributed chocolates to 5-/6-year-old participants and partners they were paired with. Participants always possessed, through some means, two chocolates when the experimenter returned after a brief absence, and they had to decide whether to take an extra one for themselves. To measure the extent to which children were concerned with actually being fair versus appearing fair, two conditions were created in which children were led to believe that the experimenter did not know that the distributions had become equal. In the windfall condition, a confederate gave one additional chocolate to the participant, and in the partner condition, the partner transferred one chocolate to the participant. Compared to the control condition, participants who passed the false belief task in both of these conditions tried to appear fair in their distribution. Thus 5-/6-year-old children seem to prefer appearing fair to others regardless of the situation.     

Omission bias and perceived intention in children and adults

Omission bias refers to the tendency to judge acts of commission as morally worse than equivalent acts of omission. Children aged 7–8 and 11–12 years, as well as adults, made moral judgements about acts of commission and omission in two conditions in which the protagonist obtained a self‐directed benefit. In the antisocial condition, the other person was harmed; in the selfish condition, the other person was not harmed. The results showed that adults and both age groups of children judged that the agent who did something (act of commission) was morally worse than the agent who did nothing (omission) for both antisocial and selfish conditions, although this judgement tendency was clearer in the selfish condition than in the antisocial condition. Agent intention was held constant across commission and omission, but most participants rated the intention of the agent who did something as stronger than that of the agent who did nothing. These results suggest that omission bias occurs regardless of differences in age and situation. In addition, perceived intention appears to change in conjunction with omission bias.