Evidence of Dopaminergic Processing of Executive Inhibition

Inhibition of unwanted response is an important function of the executive system. Since the inhibitory system is impaired in patients with dysregulated dopamine system, we examined dopamine neurotransmission in the human brain during processing of a task of executive inhibition. The experiment used a recently developed dynamic molecular imaging technique to detect and map dopamine released during performance of a modified Eriksen's flanker task. In this study, young healthy volunteers received an intravenous injection of a dopamine receptor ligand (11C-raclopride) after they were positioned in the PET camera. After the injection, volunteers performed the flanker task under Congruent and Incongruent conditions in a single scan session. They were required to inhibit competing options to select an appropriate response in the Incongruent but not in the Congruent condition. The PET data were dynamically acquired during the experiment and analyzed using two variants of the simplified reference region model. The analysis included estimation of a number of receptor kinetic parameters before and after initiation of the Incongruent condition. We found increase in the rate of ligand displacement (from receptor sites) and decrease in the ligand binding potential in the Incongruent condition, suggesting dopamine release during task performance. These changes were observed in small areas of the putamen and caudate bilaterally but were most significant on the dorsal aspect of the body of left caudate. The results provide evidence of dopaminergic processing of executive inhibition and demonstrate that neurochemical changes associated with cognitive processing can be detected and mapped in a single scan session using dynamic molecular imaging

Comparative genetic, proteomic and phosphoproteomic analysis of C. <i>elegans </i>embryos with a focus on <i>ham</i>-1/STOX and <i>pig</i>-1/MELK in dopaminergic neuron development

Asymmetric cell divisions are required for cellular diversity and defects can lead to altered daughter cell fates and numbers. In a genetic screen for C. elegans mutants with defects in dopaminergic head neuron specification or differentiation, we isolated a new allele of the transcription factor HAM-1 [HSN (Hermaphrodite-Specific Neurons) Abnormal Migration]. Loss of both HAM-1 and its target, the kinase PIG-1 [PAR-1(I)-like Gene], leads to abnormal dopaminergic head neuron numbers. We identified discrete genetic relationships between ham-1, pig-1 and apoptosis pathway genes in dopaminergic head neurons. We used an unbiased, quantitative mass spectrometry-based proteomics approach to characterise direct and indirect protein targets and pathways that mediate the effects of PIG-1 kinase loss in C. elegans embryos. Proteins showing changes in either abundance, or phosphorylation levels, between wild-type and pig-1 mutant embryos are predominantly connected with processes including cell cycle, asymmetric cell division, apoptosis and actomyosin-regulation. Several of these proteins play important roles in C. elegans development. Our data provide an in-depth characterisation of the C. elegans wild-type embryo proteome and phosphoproteome and can be explored via the Encyclopedia of Proteome Dynamics (EPD) - an open access, searchable online database

BMQ

BMQ: Boston Medical Quarterly was published from 1950-1966 by the Boston University School of Medicine and the Massachusetts Memorial Hospitals

An Analysis of Patent Length: Encouraging Innovation by Shortening Patent Protection

Despite the fact that new products are a central concern of modern marketing theory, the marketing literature has had little to suggest about appropriate public policy for encouraging innovation. This article analyzes the issue of the appropriate length for patent protection. Recent research on pioneer brand advantage can provide a much-needed rationale for the length of time a product should be protected. This research suggests that the overall progress of innovation would benefit if legal protection were shorter than the current 17-year patent for certain types of products

Pioneer brand advantage and consumer behavior: A conceptual framework and propositional inventory

What are the behavioral origins of pioneer brand advantage? This article provides an integrative conceptual framework and propositional inventory to help more fully understand this multifaceted phenomenon. It is proposed that there are three sources of entry-order information that work through various psychological processes and affect multiple decision process variables. The conceptual framework translates into eight testable propositions. New exploratory evidence is presented. Managerial implications are discussed

Corporate claims as innovator or market leader: impact on overall attitude and quality perceptions and transfer to company brands

The research described in this paper examines two corporate ability (CA)associations at both company and product perception levels through the use of two category exemplar cues, market leadership and market pioneership. The research investigates the directionality and degree to which company claims as being either a market leader or pioneer impact upon consumers' perceptions of the company and also the products produced by the company. Results show that describing a company as a pioneer or market leader leads to a more favorable attitude toward the company but does not trickle down to its products. In addition, it has (as hypothesized) no impact on quality perceptions. In addition, it was shown that when a company is designated as a market leader it is significantly more likely to be perceived as having the potential to introduce the market leading brand in a new category relative to when no such designation is made. No evidence was found that a designation as an innovative company leads to the perception that the company can pioneer a new category. The managerial implications of these findings are discussed

Consumers' perception and misperception of market leadership and market pioneership

Does a brand benefit from being perceived as market leader or market pioneer? What happens when a brand is misperceived as market leader or market pioneer? This research presents an empirical design that tests if consumer awareness of market leadership and market pioneership has an impact on brand evaluation and preference. The research also introduces the concept of consumer misperception of which brand was market leader or market pioneer. The potential difficulties of using perceptions of real brands in research are addressed through a within-brand comparison approach. Through a survey approach using a household research panel, the manuscript examines the prevalence of such misperception, and the degree to which brand evaluation, attitude, and purchase intention are impacted by the correct perception or misperception that the brand is a market leader or pioneer. Survey results generally show a significant enhancement in brand evaluation for those brands perceived as leaders or pioneers relative to followers. Perceived market leadership is associated with more favourable evaluation relative to perceived pioneership. Brands misperceived as the market leader or pioneer brand accrue all of the benefits of brands correctly perceived as market leader and pioneer brands. Managerial implications of these findings are discussed in terms of the significance of market leadership and market pioneership as positioning bases, and in what situations are they most useful. These characteristics, market leadership and market pioneership, are linked to the literature on market share effects and customer-based brand equit