Mushroom bodies of the honeybee brain show cell population-specific plasticity in expression of amine-receptor genes

Dopamine and octopamine released in the mushroom bodies of the insect brain play a critical role in the formation of aversive and appetitive memories, respectively. As recent evidence suggests a complex relationship between the effects of these two amines on the output of mushroom body circuits, we compared the expression of dopamine- and octopamine-receptor genes in three major subpopulations of mushroom body intrinsic neurons (Kenyon cells). Using the brain of the honeybee, Apis mellifera, we found that expression of amine-receptor genes differs markedly across Kenyon cell subpopulations. We found, in addition, that levels of expression of these genes change dramatically during the lifetime of the bee and that shifts in expression are cell population-specific. Differential expression of amine-receptor genes in mushroom body neurons and the plasticity that exists at this level are features largely ignored in current models of mushroom body function. However, our results are consistent with the growing body of evidence that short- and long-term olfactory memories form in different regions of the mushroom bodies of the brain and that there is functional compartmentalization of the modulatory inputs to this multifunctional brain center.     

Strategic development in exact calculation: group and individual differences in four achievement subtypes

This longitudinal study sought to identify developmental changes in strategy use between 5 and 7 years of age when solving exact calculation problems. Four mathematics and reading achievement subtypes were examined at four time points. Five strategies were considered: finger counting, verbal counting, delayed retrieval, automatic retrieval, and derived fact retrieval. Results provided unique insights into children's strategic development in exact calculation at this early stage. Group analysis revealed relationships between mathematical and/or reading difficulties and strategy choice, shift, and adaptiveness. Use of derived fact retrieval by 7 years of age distinguished children with mathematical difficulties from other achievement subtypes. Analysis of individual differences revealed marked heterogeneity within all subtypes, suggesting (inter alia) no marked qualitative distinction between our two mathematical difficulty subtypes.     

Arbitrary reference

Two fundamental rules of reasoning are Universal Generalisation and Existential Instantiation. Applications of these rules involve stipulations (even if only implicitly) such as ??Let n be an arbitrary number?? or ??Let John be an arbitrary Frenchman??. Yet the semantics underlying such stipulations are far from clear. What, for example, does ??n?? refer to following the stipulation that n be an arbitrary number? In this paper, we argue that ??n?? refers to a number??an ordinary, particular number such as 58 or 2,345,043. Which one? We do not and cannot know, because the reference of ??n?? is fixed arbitrarily. Underlying this proposal is a more general thesis: Arbitrary Reference (AR): It is possible to fix the reference of an expression arbitrarily. When we do so, the expression receives its ordinary kind of semantic-value, though we do not and cannot know which value in particular it receives. Our aim in this paper is defend AR. In particular, we argue that AR can be used to provide an account of instantial reasoning (one that is better than the prominent alternatives), and we suggest that AR can also figure in offering new solutions to a range of difficult philosophical puzzles.     

Cumulative Effects of Mothers’ Risk and Promotive Factors on Daughters’ Disruptive Behavior

Little is known about the ways in which the accumulation of maternal factors increases or reduces risk for girls' disruptive behavior during preadolescence. In the current study, maternal risk and promotive factors and the severity of girls' disruptive behavior were assessed annually among girls' ages 7-12 in an urban community sample (N?=?2043). Maternal risk and promotive factors were operative at different time points in girls' development. Maternal warmth explained variance in girls' disruptive behavior, even after controlling for maternal risk factors and relevant child and neighborhood factors. In addition, findings supported the cumulative hypothesis that the number of risk factors increased the chance on girls' disruptive behavior disorder (DBD), while the number of promotive factors decreased this probability. Daughters of mothers with a history of Conduct Disorder (CD) were exposed to more risk factors and fewer promotive factors compared to daughters of mothers without prior CD. The identification of malleable maternal factors that can serve as targets for intervention has important implications for intergenerational intervention. Cumulative effects show that the focus of prevention efforts should not be on single factors, but on multiple factors associated with girls' disruptive behavior.     

Patterns of Adolescents’ Beliefs About Fighting and Their Relation to Behavior and Risk Factors for Aggression

This study examined adolescents' patterns of beliefs about aggression, and how these patterns relate to aggressive and prosocial behavior, and to risk factors associated with aggression. A sample of 477 sixth graders from two urban schools and a school in a nearby county completed measures of beliefs, behavior, and individual, peer and parental factors associated with aggression. Teacher ratings of participants' behavior and emotion regulation were also obtained. The urban sample was 84% African American; the county school was in a rural fringe area with a student population that was 45% Caucasian and 40% African American. Latent class analysis of items on a beliefs measure supported hypotheses predicting three groups: (a) a Beliefs Against Fighting (BAGF) group that opposed the use of aggression (31% of the sample); (b) a Fighting is Sometimes Necessary (FSNEC) group that endorsed beliefs that fighting is sometimes necessary or inevitable (41%), and (c) a Beliefs Supporting Fighting (BSUPF) group that supported aggression across multiple contexts (28%). Differences across groups were found on race/ethnicity and family structure, but not on gender. Significant differences were also found such that the FSNEC group fell between levels of the BAGF and BSUPF groups on most measures. In contrast, the FSNEC and BAGF groups both differed from the BSUPF group, but not from each other on measures of empathy, perceived effectiveness of nonviolence and aggression, and parental messages supporting nonviolence. These differences suggest the need for tailoring prevention approaches for subgroups of adolescents who differ in their patterns of beliefs.     

Grief and trauma intervention for children after disaster: exploring coping skills versus trauma narration

This study evaluated the differential effects of the Grief and Trauma Intervention (GTI) with coping skills and trauma narrative processing (CN) and coping skills only (C). Seventy African American children (6-12 years old) were randomly assigned to GTI-CN or GTI-C. Both treatments consisted of a manualized 11-session intervention and a parent meeting. Measures of trauma exposure, posttraumatic stress symptoms, depression, traumatic grief, global distress, social support, and parent reported behavioral problems were administered at pre, post, 3 and 12 months post intervention. In general, children in both treatment groups demonstrated significant improvements in distress related symptoms and social support, which, with the exception of externalizing symptoms for GTI-C, were maintained up to 12 months post intervention. Results suggest that building coping skills without the structured trauma narrative may be a viable intervention to achieve symptom relief in children experiencing trauma-related distress. However, it may be that highly distressed children experience more symptom relief with coping skills plus narrative processing than with coping skills alone. More research on the differential effects of coping skills and trauma narration on child distress and adaptive functioning outcomes is needed.