Impaired reward processing by anterior cingulate cortex in children with attention deficit hyperactivity disorder

Decades of research have examined the neurocognitive mechanisms of cognitive control, but the motivational factors underlying task selection and performance remain to be elucidated. We recently proposed that anterior cingulate cortex (ACC) utilizes reward prediction error signals carried by the midbrain dopamine system to learn the value of tasks according to the principles of hierarchical reinforcement learning. According to this position, disruption of the ACC–dopamine interface can disrupt the selection and execution of extended, task-related behaviors. To investigate this issue, we recorded the event-related brain potential (ERP) from children with attention deficit hyperactivity disorder (ADHD), which is strongly associated with ACC–dopamine dysfunction, and from typically developing children while they navigated a simple “virtual T-maze” to find rewards. Depending on the condition, the feedback stimuli on each trial indicated that the children earned or failed to earn either money or points. We found that the reward positivity, an ERP component proposed to index the impact of dopamine-related reward signals on ACC, was significantly larger with money feedback than with points feedback for the children with ADHD, but not for the typically developing children. These results suggest that disruption of the ACC–dopamine interface may underlie the impairments in motivational control observed in childhood ADHD.     

An Inequality for Correlations in Unidimensional Monotone Latent Variable Models for Binary Variables

It is shown that a unidimensional monotone latent variable model for binary items implies a restriction on the relative sizes of item correlations: The negative logarithm of the correlations satisfies the triangle inequality. This inequality is not implied by the condition that the correlations are nonnegative, the criterion that coefficient H exceeds 0.30, or manifest monotonicity. The inequality implies both a lower bound and an upper bound for each correlation between two items, based on the correlations of those two items with every possible third item. It is discussed how this can be used in Mokken’s (A theory and procedure of scale-analysis, Mouton, The Hague, 1971) scale analysis.     

Errors without conflict: implications for performance monitoring theories of anterior cingulate cortex

Recent theories of the neural basis of performance monitoring have emphasized a central role for the anterior cingulate cortex (ACC). Replicating an earlier event-related potential (ERP) study, which showed an error feedback negativity that was modeled as having an ACC generator, we used event-related fMRI to investigate whether the ACC would differentiate between correct and incorrect feedback stimuli in a time estimation task. The design controlled for response conflict and frequency and expectancy effects. Although participants in the current study adjusted their performance following error feedback, we did not observe error feedback-evoked ACC activity. In contrast, we did observe ACC activity while the same subjects performed the Stroop task, in which an area of the ACC activated during both conflict and error trials. These findings are inconsistent with previous dipole models of the error feedback negativity, and suggest the ACC may not be involved in the generation of this ERP component. These results question involvement of the ACC in the detection of errors per se when controlling for conflict.     

A mechanism for error detection in speeded response time tasks

The concept of error detection plays a central role in theories of executive control. In this article, the authors present a mechanism that can rapidly detect errors in speeded response time tasks. This error monitor assigns values to the output of cognitive processes involved in stimulus categorization and response generation and detects errors by identifying states of the system associated with negative value. The mechanism is formalized in a computational model based on a recent theoretical framework for understanding error processing in humans (C. B. Holroyd & M. G. H. Coles, 2002). The model is used to simulate behavioral and event-related brain potential data in a speeded response time task, and the results of the simulation are compared with empirical data.     

A cross-linguistic data bank for oral picture naming in Dutch, English, German, French, Italian, Russian, Spanish, and Swedish (PEDOI)

The well established effect of word frequency on adult's picture naming performance is now called into question. This is particularly true for variables which are correlated with frequency, as is the case of age of word acquisition. Since the work of [Carrol and White, 1973] there is growing agreement among researchers to confer an important role in lexical access to this variable. Indeed, it has been shown ( [Hodgson and Ellis, 1998]) that for normal English-speaking adults only the variables 'age-of-acquisition' and 'name agreement' are independent predictors of naming success among the various variables considered. However, when brain-damaged subjects with and without degenerative pathologies are studied, word frequency and word length as well as concept familiarity all give significant effects ( [Hirsh and Funnell, 1995]; [Lambon Ralph et al., 1998]; [Nickels and Howard, 1995]). Finally, it has been suggested that the production of specific error types may be related to such variables. According to [Nickels and Howard, 1994] the production of semantic errors is specifically affected by 'imageability' and in the recent study by [Kremin et al., 2001] 'age of acquisition' predicts (frank) word finding difficulties.     

Personality and Health in the 1980s: Psychosomatic Medicine Revisited?

This special issue is a sign of a resurgence of interest in the role of personality in health not seen since the 1940s and early 1950s when the promises of the psychosomatic approach to health and illness appeared to be the greatest. This new look at personality and health represented by contributions to this special issue attempts to address the limitations of earlier work in psychosomatic medicine by making more explicit efforts to define personality variables precisely, to distinguish these variables from conceptually related psychological constructs, and to embed them in a body of theory and empirical research. This new work also attempts to remedy methodological limitations of earlier work by placing greater emphasis on prospective research and highlighting distinctions between symptom reports, illness behavior, and actual illness. However, the new work and earlier work in psychosomatic medicine share certain working assumptions, for example, a primary emphasis on the relatively direct impact of personality on disease onset, an assumption that personality variables operate in interaction with stressful events, and a frequent emphasis on general susceptibility to disease. Moreover, this new work frequently risks the same methodological pitfalls that limited scientific progress in psychosomatic medicine. We argue that the rapid rise and decline of psychosomatic medicine is most likely to be repeated in research on personality and health in the 1980s if reasonable criteria for considering personality variables a risk factor for disease are not precisely defined, disease endpoints (the dependent variable) are not assessed precisely, personality variables of interest (the independent variable) are not empirically distinguished from other related psychological variables, and complex relationships among risk factors are not taken into account. It is emphasized that models drawn from personality research cannot be transferred unchanged to the health arena without risking false inferences about the role of personality in health.     

Physiologic and self-report comparisons between tension headache sufferers and nonheadache controls

Tension headache sufferers and nonheadache controls were compared with respect to (1) frontal EMG during both baseline and presentation of an imagined stressor, (2) trait anxiety, (3) locus of control expectancies for health related behaviors, and (4) exposure to stressful life events. Tension headache sufferers displayed higher resting muscle tension levels than did nonheadache controls. However, both groups responded similarly to the imagined stress stimulus and displayed significant muscle tension elevations of similar magnitude. While tension headache sufferers reported higher levels of trait anxiety, no differences were found between the two groups for locus of control expectancies and exposure to stressful life events. The diagnostic and treatment implications of these findings are discussed.     

A conjoint measurement approach to color harmony

The aim of this study was to find a rule in color harmony that could reveal the mutual influences of the three basic harmonies, those of hue, lightness, and saturation. One hundred and four color pairs were judged for harmony by five subjects five times. The results were analyzed by the conjoint measurement algorithm of Krantz and Tversky (1971). It was concluded that there is an interaction between saturation harmony and hue and lightness harmony together, and an additivity between hue harmony and lightness harmony. This implies the rule: color harmony = saturation harmony * (hue harmony + lightness harmony).     

Instructional strategy effects on the retention and transfer of procedures of different difficulty level

In the present study, the effects of two instructional strategies on the retention and transfer of procedures of different difficulty level were investigated. Difficulty level was manipulated by providing a different number of cues during training. The instructional strategies differed with respect to the amount of contextual interference. Sixty-four subjects were randomly assigned to either a high interference group or a low interference group. Retention and transfer were measured immediately following training and after a three-week delay. The dependent variables were number of errors and decision time. Results showed no differences between the two training groups over the various difficulty levels. Results further showed that retention performance increased as fewer cues were available during practice. It is suggested that ‘delayed automatization’ can account for the observed increment in performance level. It is further suggested that contextual interference may produce delayed automatization of task performance but is only effective if relationships can be discovered in the learning material.     

Relational Autonomy and Paternalistic Interventions

Relational conceptions of autonomy attempt to take into account the social aspects of autonomous agency. Those views that incorporate not merely causally, but constitutively necessary relational conditions, incorporate a condition that has the form:

(RelAgency) A necessary condition for autonomous agency is that the agent stands in social relations S.

I argue that any account that incorporates such a condition (irrespective of how the relations, S, are spelt out) cannot play one of autonomy’s key normative roles: identifying those agents who ought to be protected from (hard) paternalistic intervention. I argue, against objections from Oshana, that there are good reasons for maintaining the notion of autonomy in this role, and thus that such relational conceptions should not be accepted. This rejection goes beyond that from John Christman, which holds only for those relational conditions which are value-laden.