Postsynaptic nigrostriatal dopamine receptors and their role in movement regulation

The article presents the hypothesis that nigrostriatal dopamine may regulate movement by modulation of tone and contraction in skeletal muscles through a concentration-dependent influence on the postsynaptic D1 and D2 receptors on the follow manner: nigrostriatal axons innervate both receptor types within the striatal locus somatotopically responsible for motor control in agonist/antagonist muscle pair around a given joint. D1 receptors interact with lower and D2 receptors with higher dopamine concentrations. Synaptic dopamine concentration increases immediately before movement starts. We hypothesize that increasing dopamine concentrations stimulate first the D1 receptors and reduce muscle tone in the antagonist muscle and than stimulate D2 receptors and induce contraction in the agonist muscle. The preceded muscle tone reduction in the antagonist muscle eases the efficient contraction of the agonist. Our hypothesis is applicable for an explanation of physiological movement regulation, different forms of movement pathology and therapeutic drug effects. Further, this hypothesis provides a theoretical basis for experimental investigation of dopaminergic motor control and development of new strategies for treatment of movement disorders

Common SNP-Based Haplotype Analysis of the 4p16.3 Huntington Disease Gene Region.

Age at the onset of motor symptoms in Huntington disease (HD) is determined largely by the length of a CAG repeat expansion in HTT but is also influenced by other genetic factors. We tested whether common genetic variation near the mutation site is associated with differences in the distribution of expanded CAG alleles or age at the onset of motor symptoms. To define disease-associated single-nucleotide polymorphisms (SNPs), we compared 4p16.3 SNPs in HD subjects with population controls in a case:control strategy, which revealed that the strongest signals occurred at a great distance from the HD mutation as a result of "synthetic association" with SNP alleles that are of low frequency in population controls. Detailed analysis delineated a prominent ancestral haplotype that accounted for ∼50% of HD chromosomes and extended to at least 938 kb on about half of these. Together, the seven most abundant haplotypes accounted for ∼83% of HD chromosomes. Neither the extended shared haplotype nor the individual local HTT haplotypes were associated with altered CAG-repeat length distribution or residual age at the onset of motor symptoms, arguing against modification of these disease features by common cis-regulatory elements. Similarly, the 11 most frequent control haplotypes showed no trans-modifier effect on age at the onset of motor symptoms. Our results argue against common local regulatory variation as a factor influencing HD pathogenesis, suggesting that genetic modifiers be sought elsewhere in the genome. They also indicate that genome-wide association analysis with a small number of cases can be effective for regional localization of genetic defects, even when a founder effect accounts for only a fraction of the disorder

Brief positive psychological interventions within multi-cultural organisational contexts: a systematic literature review

Applications of brief positive psychology interventions (BPPI) within organisational contexts have soared within the last decade; yet academic literature on its effectiveness is limited. However, critics have raised concerns about the applicability, replicability and generalizability of those BPPIs published within academic literature; especially when applied within multi-cultural contexts. Given the ever-increasing diversity of the workforce due to factors such as globalization, migration and immigration, it is imperative to consider cultural context to design effective and meaningful BPPIs. While present literature addresses specific BPPIs in clinical samples and monocultural contexts, limited research exists with respect to the design of BPPIs applicable to multi-cultural organisational contexts. Therefore, the purpose of this chapter is to provide a systematic literature review on multi-cultural BPPIs within organisational contexts and to present an overview of advances to date. We conducted a systematic literature review in Medline and PsycINFO using a comprehensive list of relevant search terms (2000–2018) to identify studies on multi-cultural BPPIs within organisational contexts. Findings provide support for the short-term effectiveness of various types of BPPIs in multi-cultural organisational contexts, however, the statistical power and long-term effects of these studies are questionable. Specifically, it seems that workplace mindfulness-based training, (web-based and multi-modal) stress management, and acceptance and commitment therapy mitigate consequences like stress and burnout, though more evidence is needed to support that BBPIs actively promote positive psychological outcomes. This chapter presents an overview of advances made to-date and aims to encourage researchers to consider multi-cultural aspects when developing BPPI interventions.\u3cbr/\u3e\u3cbr/\u3eKeywords\u3cbr/\u3eBrief positive psychological interventions Multi-cultural contexts Intervention research Systematic literature revie