Nicotinic cholinergic synaptic mechanisms in the ventral tegmental area contribute to nicotine addiction

Tobacco use is a major health problem that is estimated to cause 4 million deaths a year worldwide. Nicotine is the main addictive component of tobacco. It acts as an agonist to activate and desensitize nicotinic acetylcholine receptors (nAChRs). A component of nicotine's addictive power is attributable to actions on the mesolimbic dopaminergic system, which serves a fundamental role in the acquisition of behaviors that are inappropriately reinforced by addictive drugs. Here we show that nicotine, in the same concentration and time ranges as obtained from tobacco, has three main actions that regulate the activity of midbrain dopamine (DA) neurons. Nicotine first activates and then desensitizes nAChRs on the DA neurons. This process directly excites the DA neurons for a short period of time before the nAChRs desensitize. Nicotine also enhances glutamatergic excitation and decreases GABAergic inhibition onto DA neurons. These events increase the probability for synaptic plasticity, such as long-term potentiation. The short-lived direct excitation of the DA neurons coupled with the enhanced glutamatergic afferent activity provides the presynaptic and postsynaptic coincidence necessary to initiate synaptic potentiation. In total, these synaptic events lead to a relatively long-lasting heightened activity of midbrain DA neurons. Consistent with other summarized studies, this work indicates that the synaptic changes normally associated with learning and memory can be influenced and commandeered during the nicotine addiction process.     

Willingness to Use ADHD Self-Management: Mixed Methods Study of Perceptions by Adolescents and Parents

Little is known about perceptions surrounding self-management for attention deficit hyperactivity disorder (ADHD), although such interventions appear commonly used and are considered essential components of the chronic care model. Our research is part of a mixed methods study that followed students at high and low risk for ADHD over 11 years. During the final study years, area-representative samples of 148 adolescents (54.8 % participation; 97 ADHD high-risk group; 51 low-risk peers) and 161 parents (59.4 % participation; 108 parents of high-risk adolescent; 53 parents of low-risk peer) completed a cross-sectional survey on community-identified self-management interventions for ADHD (activity outlets, sleep regulation, dietary restriction, homework help, family rules, and prayer). Respondents also answered open-ended questions addressing undesirable self-management effects, which were analyzed using grounded theory methods. High-risk adolescents expressed significantly lower willingness towards all self-management interventions than did adult respondents, except for increased activity outlets. They also reported lower receptivity towards sleep regulation and dietary restriction than did their low-risk peer group. No gender or race differences in self-management willingness were found, except for higher receptivity to prayer in African American respondents. Cost, perceived ineffectiveness, disruptions to routines, causation of interpersonal conflicts, and reduced future self-reliance were seen as potential undesirable effects. Findings suggest that activity-based ADHD interventions appear particularly acceptable across all demographic and risk groups, unlike sleep regulation and dietary approaches. Further research on self-care effectiveness is needed to incorporate adolescents’ viewpoints about ADHD self-management, as interventions may be acceptable to adults, but resisted by adolescents.     

An examination of practice and laterality effects on the Purdue Pegboard and Moving Beans with Tweezers

The purpose of this study was to examine the relation of practice or learning and laterality on the Purdue Pegboard and the Moving Beans with Tweezers test. The subjects were 30 right-handed, healthy young male adults (age: M = 21.1, SD = 1.9 yr.). The subjects performed both tests five times with each hand. A two-way analysis of variance (hand x trial) for scores on the Purdue Pegboard showed that Trial 1 had a significantly lower mean than Trials 4 and 5 with the dominant hand, and scores on Trials 1 and 3 were lower than that on Trial 5 for the nondominant hand. For the Moving Beans with Tweezers test, Trial 1 had a significantly lower score than Trial 5 with the nondominant hand. The dominant hand produced significantly higher values on all trials of both tests. Intraclass correlation coefficients of Trials 2 and 3 were high, and means were significantly higher for the dominant hand. A correlation between other tests was not high (r = .37-.46) for both hands. All correlations among five trials on both tests were significant and high (Purdue Pegboard-Dominant: average r =.72, [r] = .60-.80, Purdue Pegboard-Nondominant: average r = .59, [r] = .43-.76), (Moving Beans-Dominant: average r = .74, [r] = .57-.81, Moving Beans-Nondominant: average r =.71, [r] = .55-.87). Correlations among five trials for the ratio of dominant:nondominant hand on both tests were significant and moderate (Moving Beans: average r = .28, [r] = .08-.57, Purdue Pegboard: average r = .41, [r] = .19.56). Performance with the dominant hand is superior to that of the nondominant hand on both tests. Practice effects are found for both tests across five trials. The Moving Beans with Tweezers test also showed laterality of practice effects. The two tests may measure different abilities.     

Developmental order driving the relationship between executive functions and theory of mind: a case study

Several studies have suggested there is a developmental link between executive functions and theory of mind. However, the developmental order driving the relationship is not well understood. The main reason is that the development of executive function parallels the development of theory of mind in normally developing children. In this paper, a case (H.Y.) is reported. H.Y. had lived in a persistent vegetative state for 6 years after encephalitis at the age of 10. He showed a developmental order driving the relationship between executive functions and theory of mind. These findings are consistent with recent suggestions that development of executive function might be important as a predecessor of either the ability to understand false beliefs or the ability to express that understanding.     

A laser-based eye-tracking system

This paper reports on the development of a new eye-tracking system for noninvasive recording of eye movements. The eye tracker uses a flying-spot laser to selectivelyimage landmarks on the eye and, subsequently, measure horizontal, vertical, and torsional eye movements. Considerable work was required to overcome the adverse effects of specular reflection of the flying-spot from the surface of the eye onto the sensing elements of the eye tracker. These effects have been largely overcome, and the eye-tracker has been used to document eye movement abnormalities, such as abnormal torsional pulsion of saccades, in the clinical setting.     

Cultural differences related to positive and negative valence

Differences between North American and East Asian cultures were examined in terms of the valence of psychological constructs. Americans were more likely than Japanese to focus on positive things. In contrast, Japanese ( vs Americans) were more likely to attend to negative information of the self, but not more or less likely to focus on negative things about others. Based on within-culture analyses, the Americans' data were better described by their tendency to focus on positive things over negative things than by their tendency for self-enhancement. In contrast, the Japanese data were better described by their self-critical tendency. This result was replicated in a second study. In addition, correlations between constructs with opposite valences were negative in the USA, but positive or absent in Japan.     

Photoinduced volume changes related to photoinduced anisotropy in chalcogenide glasses

We report metastable photoinduced volume expansion (hyperexpansion) of up to 10 µm in height and several millimetres in diameter for the chalcogenide glass As 2 S 3 . This is an order of magnitude larger than reported to date in any material, including chalcogenide glasses. We suggest a model for the effect and propose that its origin is similar to the origin of photoinduced anisotropy in glassy chalcogenides proposed earlier. The model is based on the anisotropic chemical bonding found in most chalcogenide glasses; the anisotropy arises from the fact that chalcogen atoms exhibit both strong covalent bonding and weak van der Waals bonding. The origin of the photoinduced volume changes (expansion and contraction) is in a thermally induced diffusion, or athermal tunnelling, of photoexcited chalcogen atoms, with possible subsequent sublimation from the sample surface. The primary role of hyperpolarizable van der Waals bonds is supported by the absence of photoinduced volume changes in the chalcogenide glass Ga 1.4 La 0.6 S 3, in which chalcogen atoms do not bond via van der Waals bonds.     

Effects of the Central Executive on Postural Control

The authors focused on individual working memory (WM) capacity and examined its effect on postural control. Participants were 79 young volunteers split into two groups of low- and high WM span, based on scores from the Reading Span Test. The length of unrest was measured in the following conditions: double-leg standing as a single (D-S) task, single-leg standing as a single (S-S) task, double-leg standing as a dual (D-D) task, and single-leg standing as a dual (S-D) task. Regarding inte-group comparisons, total length was prolonged significantly between the low- and the high-span groups but only on the S-D task. The present results revealed that dual-task interference emerged in the low-span group when in a more unstable posture.