A computational model of anterior cingulate function in speeded response tasks: effects of frequency,sequence, and conflict

A growing body of evidence from functional neuroimaging and computational modeling studies indicates that the anterior cingulate cortex (ACC) detects the presence of response conflict and conveys this information to other brain regions, enabling subsequent adjustments in cognitive control. The present study examined previous empirical findings of increased ACC for low-frequency stimuli across three distinct speeded response tasks (two-alternative forced choice, go/no-go, and oddball). Simulations conducted in a neural network model incorporating sequential priming mechanisms (developed in Cho et al., 2002) confirmed that a computational measure of response conflict was higher on low-frequency trials across all three tasks. In addition, the model captured detailed aspects of behavioral reaction time and accuracy data, predicted the dynamics of ACC activity related to trial sequence effects, and provided evidence for the functional role of conflict information in performance monitoring and optimization. The results indicate that the conflict-monitoring hypothesis, augmented by mechanisms for encoding stimulus history, can explain key phenomena associated with performance in sequential speeded response tasks.     

The effect of specific test queries on source-monitoring event-related potentials

Source-monitoring decision processes were manipulated during retrieval while event-related potentials (ERPs) were recorded. Words were either seen or heard at study, and memory for modality was measured on two separate yes-no source tests. Decision processes were varied across the two tests by asking participants to respond to leading questions. One leading question asked if the items were seen at study, whereas the second question asked if the items were heard at study (cf., Marsh & Hicks, 1998). Behavioral responses indicated that leading questions altered the way in which memory was evaluated to determine the source of information. Varying the decision processes affected frontal--but not parietal ERPs--indicating that frontal ERPs reflect processing that is used to evaluate activated information. Furthermore, left and right frontal ERP activity was affected by the combination of test query and type of source supporting the hypothesis that both the right and left frontal lobes contribute to memory retrieval processes. The pattern of frontal ERP effects supports the hypothesis that activation in right frontal areas reflect basic decision processes that are used to determine source and that the left frontal lobes are recruited when more systematic processing is required by the test context (cf., Nolde, Johnson, & Raye, 1998b).     

The hippocampus and memory of verbal and pictorial material

Recognition of words and kaleidoscope pictures showed a double dissociation of left and right hippocampal activity using magnetic source imaging (MSI). MSI has advantages over alternative imaging techniques that measure hemodynamic changes for identifying regional changes in brain activity in real time and on an individual subject basis without the need for image subtraction. In this study, lists of words or kaleidoscope pictures were presented for memorization followed by tests of list items and foils during which brain activity was recorded. There was greater activation in the left than the right hippocampus with abstract nouns (e.g., relief) and greater activation in the right than the left hippocampus with kaleidoscope pictures. This dissociation was evident on a case by case basis. This study demonstrates the specialization of the two medial temporal lobe (MTL) regions, including the hippocampi, for mnemonic processing of verbal and pictorial items that are difficult to encode verbally.     

Pettit on Consequentialism and Universalizability

Philip Pettit has argued that universalizability entails consequentialism. I criticise the argument for relying on a question-begging reading of the impartiality of universalization. A revised form of the argument can be constructed by relying on preference-satisfaction rationality, rather than on impartiality. But this revised argument succumbs to an ambiguity in the notion of a preference (or desire). I compare the revised argument to an earlier argument of Pettit’s for consequentialism that appealed to the theoretical virtue of simplicity, and I raise questions about the force of appeal to notions like simplicity and rationality in moral argument.     

Emotion-modulated performance and activity in left dorsolateral prefrontal cortex

Functional MRI (fMRI) was used to examine the relationship between processing of pleasant and unpleasant stimuli and activity in prefrontal cortex. Twenty volunteers identified the colors in which pleasant, neutral, and unpleasant words were printed. Pleasant words prompted more activity bilaterally in dorsolateral prefrontal cortex (DLPFC) than did unpleasant words. In addition, pleasant words prompted more activity in left than in right DLPFC. Response speed to pleasant words was correlated with DLPFC activity. These data directly link positive affect, enhanced performance, and prefrontal activity, providing some of the first fMRI evidence supporting models of emotional valence and frontal brain asymmetry based on electroencephalography (EEG).     

Correlates of compassion fatigue and burnout in chaplains and other clergy who responded to the September 11th attacks in New York City

Participants at a June 2002 conference about the September 11th attacks were tested for compassion fatigue, compassion satisfaction, and burnout. The sample consisted of 343 clergy, including 97 chaplains. A total of 149 (43.4%) of the participants had responded as disaster-relief workers following the September 11th attacks. The number of hours clergy worked with trauma victims each week was directly related to compassion fatigue among responders and non-responders. Compassion fatigue also was positively related to the number of days that responders worked at Ground Zero, while disaster-relief work with the American Red Cross reduced compassion fatigue and burnout. Clinical Pastoral Education tended to decrease compassion fatigue and burnout and increase compassion satisfaction in both responders and non-responders. Burnout was inversely related to age in both groups.     

The development of gaze following and its relation to language

We examined the ontogeny of gaze following by testing infants at 9, 10 and 11 months of age. Infants (N = 96) watched as an adult turned her head toward a target with either open or closed eyes. The 10- and 11-month-olds followed adult turns significantly more often in the open-eyes than the closed-eyes condition, but the 9-month-olds did not respond differentially. Although 9-month-olds may view others as 'body orienters', older infants begin to register whether others are 'visually connected' to the external world and, hence, understand adult looking in a new way. Results also showed a strong positive correlation between gaze-following behavior at 10-11 months and subsequent language scores at 18 months. Implications for social cognition are discussed in light of the developmental shift in gaze following between 9 and 11 months of age.     

Global Inequality and International Institutions

This article considers the links between international institutions and global economic justice: how international institutions might be morally important; how they have changed; and at what those changes imply for justice. The institutional structure of international society has evolved in ways that help to undercut the arguments of those who take a restrictionist position towards global economic justice. There is now a denser and more integrated network of shared institutions and practices within which social expectations of global justice and injustice have become more securely established. But, at the same time, our major international social institutions continue to constitute a deformed political order. This combination of density and deformity shapes how we should think about international justice in general and has important implications for the scope, character, and modalities of global economic justice. Having laid out a view of normative development and where it leads, the article then examines why international distributive justice remains so marginal to current practice.     

Cost-Effectiveness and Health Care Utilization in a Multidisciplinary Pain Center: Comparison of Three Treatment Groups

Recent literature supports the efficacy of multidisciplinary pain management in treating persons suffering from chronic pain. However, the components of multidisciplinary pain management need to be evaluated in terms of effects on patients' quality of life as well as saving of future health care dollars. Therefore, cost-effectiveness of three treatment groups was compared by examining treatment outcome, posttreatment health care costs, and posttreatment health care visits. Results revealed that patients receiving both medical and psychological treatment (multidisciplinary pain management) exhibited the largest improvements in functional capacity, while being the least costly after their treatment program had ended. In contrast, patients who received only medical treatment exhibited significant deterioration in outcome after their treatment ended, and consumed substantially more posttreatment health care dollars.