Pupil diameter tracks changes in control state predicted by the adaptive gain theory of locus coeruleus function

An important dimension of cognitive control is the adaptive regulation of the balance between exploitation (pursuing known sources of reward) and exploration (seeking new ones) in response to changes in task utility. Recent studies have suggested that the locus coeruleus-norepinephrine system may play an important role in this function and that pupil diameter can be used to index locus coeruleus activity. On the basis of this, we reasoned that pupil diameter may correlate closely with control state and associated changes in behavior. Specifically, we predicted that increases in baseline pupil diameter would be associated with decreases in task utility and disengagement from the task (exploration), whereas reduced baseline diameter (but increases in task-evoked dilations) would be associated with task engagement (exploitation). Findings in three experiments were consistent with these predictions, suggesting that pupillometry may be useful as an index of both control state and, indirectly, locus coeruleus function.     

Discernibility by Symmetries

In this paper I introduce a novel strategy to deal with the indiscernibility problem for ante rem structuralism. The ante rem structuralist takes the ontology of mathematics to consist of abstract systems of pure relata. Many of such systems are totally symmetrical, in the sense that all of their elements are relationally indiscernible, so the ante rem structuralist seems committed to positing indiscernible yet distinct relata. If she decides to identify them, she falls into mathematical inconsistency while, accepting their distinctness, she finds herself unable to account for it. I show that the ante rem structuralist has in fact the resources to account for the distinctness of indiscernibles and that these resources come from the very symmetry properties of the mathematical objects that seem to pose problems for her.     

Gemmules and Elements: On Darwin’s and Mendel’s Concepts and Methods in Heredity

Inheritance and variation were a major focus of Charles Darwin’s studies. Small inherited variations were at the core of his theory of organic evolution by means of natural selection. He put forward a developmental theory of heredity (pangenesis) based on the assumption of the existence of material hereditary particles. However, unlike his proposition of natural selection as a new mechanism for evolutionary change, Darwin’s highly speculative and contradictory hypotheses on heredity were unfruitful for further research. They attempted to explain many complex biological phenomena at the same time, disregarded the then modern developments in cell theory, and were, moreover, faithful to the widespread conceptions of blending and so-called Lamarckian inheritance. In contrast, Mendel’s approaches, despite the fact that features of his ideas were later not found to be tenable, proved successful as the basis for the development of modern genetics. Mendel took the study of the transmission of traits and its causes (genetics) out of natural history; by reducing complexity to simple particulate models, he transformed it into a scientific field of research. His scientific approach and concept of discrete elements (which later gave rise to the notion of discrete genes) also contributed crucially to the explanation of the existence of stable variations as the basis for natural selection.     

MR Diffusion Tensor Imaging: A Window into White Matter Integrity of the Working Brain

As Norman Geschwind asserted in 1965, syndromes resulting from white matter lesions could produce deficits in higher-order functions and “disconnexion” or the interruption of connection between gray matter regions could be as disruptive as trauma to those regions per se. The advent of in vivo diffusion tensor imaging, which allows quantitative characterization of white matter fiber integrity in health and disease, has served to strengthen Geschwind’s proposal. Here we present an overview of the principles of diffusion tensor imaging (DTI) and its contribution to progress in our current understanding of normal and pathological brain function.     

Korean Pastors and Their Wives’ Marital Satisfaction and Its Predicting Factors

This study examined to what extent Korean pastors and their wives in America were satisfied with their marital lives. It also investigated how selected factors predicted marital satisfaction among Korean pastors and their wives: communication, expression of affection, empathy, sexual satisfaction, and doing things together. Eighty-five pastors and 79 pastors’ wives (n = 164) participated in this study, and they were separately measured. The Kansas Marital Satisfaction Scale (KMSS) and Lee’s Marital Inventory (LMI) were utilized. The results found that the participants showed a high level of marital satisfaction. For Korean pastors, expression of affection and doing things together were significant predictors for marital satisfaction while only expression of affection was the significant predictor for the marital satisfaction of pastors’ wives.     

Mourning Religion? Celebrating Transformation! From Loss to Gain,from Depression to Melancholia

The article raises some questions about issues in the recently published volume Mourning religion, edited by Parsons et al. (2008).     

A Top-Down Approach to a Complex Natural System: Protein Folding

We develop a general method for applying functional models to natural systems and cite recent progress in protein modeling that demonstrates the power of this approach. Functional modeling constrains the range of acceptable structural models of a system, reduces the difficulty of finding them, and improves their fidelity. However, functional models are distinctly different from the structural models that are more commonly applied in science. In particular, structural and functional models ask different questions and provide different kinds of answers. As we clarify these differences and articulate how to use these models jointly, we extend our ability to do science and gain insight into the proper use of the terms organization, order, and emergence when describing systems in nature.     

Extending Free Pregroups with Lower Bounds

In this paper, we propose an extension of free pregroups with lower bounds on sets of pregroup elements. Pregroup grammars based on such pregroups provide a kind of an algebraic counterpart to universal quantification over type-variables. In particular, we show how our pregroup extensions can be used for pregroup grammars expressing natural-language coordination and extraction.     

Predictive Validity of the Suicide Probability Scale in a Male Inmate Population

This paper describes the predictive power of the Suicide Probability Scale (SPS) within a male inmate population. The SPS scores of 1,047 inmates from 1995 to 1996 were compared against their suicidal behaviors in the following 10 years. The SPS probability score and the scores on its four subscales were found to be significantly higher in the group that engaged in at least one of three types of suicidal behavior: suicide, non-lethal self-harm and serious suicidal intentions. However, the SPS did not discriminate the inmates who went on to commit suicide. The SPS’s capacity to predict suicidal behavior proved limited in terms of sensitivity. In this regard, the SPS’s low and high risk levels correctly identified 36% of inmates who later engaged in suicidal behavior. The specificity was 0.85. These results confirm the SPS’s predictive power with male prisoners. These findings are the first to demonstrate the predictive validity of the SPS.