Understanding the oral examination process in professional certification examinations

The subjective nature of oral examinations often lead to reliability estimates that are lower than other types of examinations (i.e., written examinations). The potentially biasing individual attributes of examiners (i.e., experience) are of particular concern since the oral examination process depends specifically upon the quality of their assessments. In addition, traditional reliability estimation procedures are not always possible for some oral exams due to the utilization of incomplete measurement designs (i.e., one examiner per candidate) resulting from the inherent high costs and complicated logistics associated with large scale oral examinations. Consequently, the current study attempts to evaluate the quality of one such exam by developing alternative indicators of exam quality using a pre-existing data set. A series of examiner agreement variables were calculated for low, moderate, and high ability candidates and subsequently correlated with each other. A series of exploratory multiple regressions were also used to evaluate the potential impact of several examiner characteristics (experience, gender, specialty, variance of scale use, and fail rate) confined in the data set. Finally, a generalizability (G) study was conducted on a subset of the examination that utilizes a complete measurement design (i.e., two examiners evaluating the same candidate, and all examiners examine all candidates) for lower ability candidates. The G study was then followed by a decision (D) study to determine both the current level of dependability with two examiners, and how much the dependability of the process would improve by adding mure examiners. The results of the current study suggest that evaluating lower ability candidates is different and more difficult than evaluating higher ability candidates. Furthermore, systematic sources of error related to examiners appears to be less or a concern than previously anticipated. Finally, the results of the G-D studies suggest that the current dependability of evaluating lower ability candidates with two examiners could be greatly improved by adding additional examiners to the process

Insulin induces long-term depression of ventral tegmental area dopamine neurons via endocannabinoids.

The prevalence of obesity has markedly increased over the past few decades. Exploration of how hunger and satiety signals influence the reward system can help us understand non-homeostatic feeding. Insulin may act in the ventral tegmental area (VTA), a critical site for reward-seeking behavior, to suppress feeding. However, the neural mechanisms underlying insulin effects in the VTA remain unknown. We demonstrate that insulin, a circulating catabolic peptide that inhibits feeding, can induce long-term depression (LTD) of mouse excitatory synapses onto VTA dopamine neurons. This effect requires endocannabinoid-mediated presynaptic inhibition of glutamate release. Furthermore, after a sweetened high-fat meal, which elevates endogenous insulin, insulin-induced LTD is occluded. Finally, insulin in the VTA reduces food anticipatory behavior in mice and conditioned place preference for food in rats. Taken together, these results suggest that insulin in the VTA suppresses excitatory synaptic transmission and reduces anticipatory activity and preference for food-related cues

A Scale-Free Systems Theory of Motivation and Addiction

Scale-free organizations, characterized by uneven distributions of linkages between nodal elements, describe the structure and function of many life-based complex systems developing under evolutionary pressures. We explore motivated behavior as a scale-free map toward a comprehensive translational theory of addiction. Motivational and behavioral repertoires are reframed as link and nodal element sets, respectively, comprising a scale-free structure. These sets are generated by semi-independent information-processing streams within cortical–striatal circuits that cooperatively provide decision-making and sequential processing functions necessary for traversing maps of motivational links connecting behavioral nodes. Dopamine modulation of cortical–striatal plasticity serves a central-hierarchical mechanism for survival-adaptive sculpting and development of motivational–behavioral repertoires by guiding a scale-free design. Drug-induced dopamine activity promotes drug taking as a highly connected behavioral hub at the expense of natural-adaptive motivational links and behavioral nodes. Conceptualizing addiction as pathological alteration of scale-free motivational–behavioral repertoires unifies neurobiological, neurocomputational and behavioral research while addressing addiction vulnerability in adolescence and psychiatric illness. This model may inform integrative research in defining more effective prevention and treatment strategies for addiction