Executive function in Parkinson’s disease: contributions of the dorsal frontostriatal pathways to action and motivation

Disruption of the dorsal frontostriatal pathways in Parkinson’s disease (PD) is associated with impairments in motivation, as well as in executive function. The goal of this study was to investigate whether these impairments are related and, if so, whether the disruption of frontostriatal pathways compromises the ability to process the motivational aspects of feedback in such tasks. In Experiment 1, informative feedback improved the performance of young, healthy participants in a task-switching paradigm. This task-switching paradigm was then used in Experiment 2 to test whether feedback would improve the performance of 17 PD patients and age-matched controls. The PD group benefitted from feedback to the same degree as control participants; however, depression scores on the Beck Depression Inventory were significantly related to feedback usage, especially when response selection demands were high. Regardless of feedback, PD patients were more impaired when response demands were high than in an equally difficult condition with low action demands. These results suggest that response selection is a core impairment of insufficient dopamine to the dorsal frontal striatal pathways.     

Weak ventral striatal responses to monetary outcomes predict an unwillingness to resist cigarette smoking

As a group, cigarette smokers exhibit blunted subjective, behavioral, and neurobiological responses to nondrug incentives and rewards, relative to nonsmokers. Findings from recent studies suggest, however, that there are large individual differences in the devaluation of nondrug rewards among smokers. Moreover, this variability appears to have significant clinical implications, since reduced sensitivity to nondrug rewards is associated with poorer smoking cessation outcomes. Currently, little is known about the neurobiological mechanisms that underlie these individual differences in the responsiveness to nondrug rewards. Here, we tested the hypothesis that individual variability in reward devaluation among smokers is linked to the functioning of the striatum. Specifically, functional magnetic resonance imaging was used to examine variability in the neural response to monetary outcomes in nicotine-deprived smokers anticipating an opportunity to smoke—circumstances found to heighten the devaluation of nondrug rewards by smokers in prior work. We also investigated whether individual differences in reward-related brain activity in those expecting to have access to cigarettes were associated with the degree to which the same individuals subsequently were willing to resist smoking in order to earn additional money. Our key finding was that deprived smokers who exhibited the weakest response to rewards (i.e., monetary gains) in the ventral striatum were least willing to refrain from smoking for monetary reinforcement. These results provide evidence that outcome-related signals in the ventral striatum serve as a marker for clinically meaningful individual differences in reward-motivated behavior among nicotine-deprived smokers.     

Reasons to attend college among ethnically diverse college students

A survey of 713 ethnically diverse university freshmen (463 Latino, 167 Asian American, 54 African American, 29 European American) assessed reasons for attending college, ethnic identity, family interdependence, and college adjustment. Results revealed three reasons for attending college not reported in previous research: to help one's family, to prove one's self-worth, and because of encouragement. Attending college to help the family was stronger among students from lower socioeconomic status backgrounds. Ethnic identity and family interdependence contributed positively to some reasons for attending college, but did not mediate ethnic differences; with cultural factors and socioeconomic status included as predictors, ethnic minority students still gave greater importance to family oriented motives than did European Americans. Career/personal and humanitarian motives contributed positively to college adjustment.     

Role of magnitude of reinforcement in spaced-trial instrumental learning in turtles (Geoclemys reevesii)

The runway performance of turtles (Geoclemys reevesii) was studied as a function of magnitude of reinforcement under spaced training conditions (one trial per day). A large reward magnitude (24 pellets) produced faster acquisition than a small magnitude (2 pellets). After a shift from the large to the small magnitude, latencies of the shifted animals continued to be significantly lower than the latencies of the non-shifted, small-magnitude controls, and similar to those of the non-shifted, large-magnitude controls. There was no evidence of the successive negative contrast effect. Extinction latencies were also significantly lower after training with the large magnitude than after training with the small magnitude; that is, there was no evidence of the magnitude of reinforcement extinction effect. The results are discussed in relation to the comparative analysis of the so-called paradoxical effects of reward, a family of learning phenomena that has not yet been found in a variety of experiments with fish, amphibians, and reptiles trained under widely spaced conditions.     

Cross‐cultural Generalizability of the Alternative Five‐factor Model Using the Zuckerman–Kuhlman–Aluja Personality Questionnaire

Several personality models are known for being replicable across cultures, such as the Five‐Factor Model (FFM) or Eysenck's Psychoticism–Extraversion–Neuroticism (PEN) model, and are for this reason considered universal. The aim of the current study was to evaluate the cross‐cultural replicability of the recently revised Alternative FFM (AFFM). A total of 15 048 participants from 23 cultures completed the Zuckerman–Kuhlman–Aluja Personality Questionnaire (ZKA‐PQ) aimed at assessing personality according to this revised AFFM. Internal consistencies, gender differences and correlations with age were similar across cultures for all five factors and facet scales. The AFFM structure was very similar across samples and can be considered as highly replicable with total congruence coefficients ranging from .94 to .99. Measurement invariance across cultures was assessed using multi‐group confirmatory factor analyses, and each higher‐order personality factor did reach configural and metric invariance. Scalar invariance was never reached, which implies that culture‐specific norms should be considered. The underlying structure of the ZKA‐PQ replicates well across cultures, suggesting that this questionnaire can be used in a large diversity of cultures and that the AFFM might be as universal as the FFM or the PEN model. This suggests that more research is needed to identify and define an integrative framework underlying these personality models. Copyright © 2016 European Association of Personality Psychology     

Evaluation of the Tobii EyeX Eye tracking controller and Matlab toolkit for research

The Tobii Eyex Controller is a new low-cost binocular eye tracker marketed for integration in gaming and consumer applications. The manufacturers claim that the system was conceived for natural eye gaze interaction, does not require continuous recalibration, and allows moderate head movements. The Controller is provided with a SDK to foster the development of new eye tracking applications. We review the characteristics of the device for its possible use in scientific research. We develop and evaluate an open source Matlab Toolkit that can be employed to interface with the EyeX device for gaze recording in behavioral experiments. The Toolkit provides calibration procedures tailored to both binocular and monocular experiments, as well as procedures to evaluate other eye tracking devices. The observed performance of the EyeX (i.e. accuracy < 0.6°, precision < 0.25°, latency < 50 ms and sampling frequency ≈55 Hz), is sufficient for some classes of research application. The device can be successfully employed to measure fixation parameters, saccadic, smooth pursuit and vergence eye movements. However, the relatively low sampling rate and moderate precision limit the suitability of the EyeX for monitoring micro-saccadic eye movements or for real-time gaze-contingent stimulus control. For these applications, research grade, high-cost eye tracking technology may still be necessary. Therefore, despite its limitations with respect to high-end devices, the EyeX has the potential to further the dissemination of eye tracking technology to a broad audience, and could be a valuable asset in consumer and gaming applications as well as a subset of basic and clinical research settings.     

Theoretical and statistical derivation of a screener for the behavioral assessment of executive functions in children

The problem of valid measurement of psychological constructs remains an impediment to scientific progress, and the measurement of executive functions is not an exception. This study examined the statistical and theoretical derivation of a behavioral screener for the estimation of executive functions in children from the well-established Behavior Assessment System for Children (BASC). The original national standardization sample of the BASC-Teacher Rating Scales for children ages 6 through 11 was used (N = 2,165). Moderate-to-high internal consistency was obtained within each factor (.80-.89). A panel of experts was used for content validity examination. A confirmatory factor analysis model with 25 items loading on 4 latent factors (behavioral control, emotional control, attentional control, and problem solving) was developed, and its statistical properties were examined. The multidimensional model demonstrated adequate fit, and it was deemed invariant after configural, metric, and scalar measurement invariance tests across sex and age. Given its strong psychometric properties, with further tests of item validity, this instrument promises future clinical and research utility for the screening of executive functions in school-age children.     

The Use of Psychoeducation for a Patient with Hepatitis C and Psychiatric Illness in Preparation for Antiviral Therapy: A Case Report and Discussion

The standard of care treatment for chronic hepatitis C viral infection (HCV) is a combination of pegylated interferon alfa and ribavirin for 24-48?weeks according to the virus genotype. This therapy is known to have multiple neuropsychiatric side effects. A major concern when evaluating a patient for HCV treatment with a known history of a psychiatric disorder is the risk that the patient's psychiatric disorder will flare or become unmanageable. The possibility of precipitating depression, confusion, mania, psychosis, hallucinations, or suicidal ideation or attempt is frequently an obstacle to treatment. We present the case of a 50?year-old man with HCV and an extensive psychiatric history involving alcoholism, depression, and suicidality who participated in a psychoeducation group to help prepare him for treatment with pegylated interferon alfa/ribavirin therapy. Though the patient derived much benefit from the psychoeducation group, by the time of evaluation for HCV treatment two months after the group ended he had relapsed back into a depressive episode with suicidal thoughts. His acute psychiatric status made him unacceptable for pegylated interferon alfa/ribavirin therapy. Psychoeducation groups show promise for helping patients with chronic medical illness to be ready for and endure intensive medical treatment that has substantial psychiatric side effects. The challenge is to help patients overcome barriers to treatment, particularly psychosocial problems, because available treatments are increasingly effective.     

Higher-Order Unification: A structural relation between Huet's method and the one based on explicit substitutions

We compare two different styles of Higher-Order Unification (HOU): the classical HOU algorithm of Huet for the simply typed λ-calculus and HOU based on the λσ-calculus of explicit substitutions. For doing so, first, the original Huet algorithm for the simply typed λ-calculus with names is adapted to the language of the λ-calculus in de Bruijn's notation, since this is the notation used by the λσ-calculus. Afterwards, we introduce a new structural notation called unification tree, which eases the presentation of the subgoals generated by Huet's algorithm and its behaviour. The unification tree notation will be important for the comparison between Huet's algorithm and unification in the λσ-calculus whose derivations are presented into a structure called derivation tree. We prove that there exists an important structural correspondence between Huet's HOU and the λσ-HOU method: for each (sub-)problem in the unification tree there exists a counterpart in the derivation tree. This allows us to conclude that the λσ-HOU is a generalization of Huet's algorithm and that solutions computed by the latter are always computed by the former method.