Inhibition of the LH Surge by Restraint Stress in Cyclic Rats: Studies on the Role of GABAA and GABAB Receptors

There is evidence that stress can alter the activity in the brain of gamma-aminobutyricacid (GABA), a neurotransmitter that has been implicated in the regulation of LH secretion. In the present study the role of GABA in the restraint stress-induced inhibition of the LH surge was investigated in the intact cyclic rat. Intracerebroventricular (icv) administration of the GABAA receptor agonist muscimol (0.1, 0.5 or 1 μg) 5 min before the presumed onset of the pro-oestrous LH surge (at 0900 h) caused a dose dependent suppression of the surge. A single dose of the GABAB receptor agonist baclofen (1 μg; icv) injected at 0855 h postponed the onset of the LH surge, and repeated injections at 0855 and 1130 h suppressed the surge. These data indicate that GABA-ergic activity in the brain can inhibit the LH surge in the cyclic rat via GABAA and GABAB receptors. Pro-oestrous rats were subjected to 5 hrs of restraint starting at 0855 h. Pretreatment with the GABAA receptor antagonist bicuculine (1 μg; icv) at 0840, 0940 and 1040 h or pretreatment with the GABAB receptor antagonist phaclofen (10 μg; icv) at 0840 h were ineffective in preventing the restraint-induced inhibition of the LH surge. The results suggest that GABAA and GABAB receptors are not involved in the inhibitory effect of restraint stress on the LH surge.     

The Effect of Age on Rule-Based Category Learning

ABSTRACT

An explicit, rule-based, category-learning task with abstract visual stimuli was administered to 50 healthy older adults and 48 younger adults. Accuracy and reaction time (RT) were examined for the effects of age, perceptual abilities, rule memory, rule complexity, stimulus novelty, and response competition. Older adults performed at equivalent levels to younger adults when applying a simple rule, but showed performance decrements when applying a more complex rule. The age effect interacted with both stimulus novelty and response competition, and was not eliminated after controlling for basic perceptual abilities and rule memory. The authors suggest that older adults show category learning deficits in conditions that require enhanced cognitive control. These results are discussed in reference to the growing body of literature regarding age-related change in executive abilities and frontal lobe function.     

Instrumentalist analyses of the functions of ethics concept-principles: a proposal for synergetic empirical and conceptual enrichment

Theoretical Medicine and Bioethics - Bioethics has made a compelling case for the role of experience and empirical research in ethics. This may explain why the movement for empirical ethics has...     

Mother-Child Interactions and Preschoolers’ Emotion Regulation Outcomes: Nurturing Autonomous Emotion Regulation

Emotion regulation is a complex process that begins in infancy and continues through childhood with parents’ support. Early parent-child interactions shape the way children learn emotion management. We took a sociocultural and social learning approach to exploring the specific components of mother-child interactions that are related to mothers’ perceptions of her child’s regulatory ability and the child’s observed emotion regulation. Thirty mothers and their preschool children were recruited from two New England urban areas: one community sample and one head start sample. Dyads engaged in a free play session, children completed an observed compliance task, and mothers completed a set of questionnaires assessing their perceptions of their child’s regulation. Regression analyses revealed that maternal behaviors during free play predicted child’s observed hostility (F _(2,29)?=?3.137, p?<?.05) and mothers’ perceptions of her child’s regulatory ability predicted observed child compliance (F _{(2, 17)}?=?4.990, p?<?.05). Child behaviors during play significantly predicted child’s compliance (F _(3,20)?=?4.722, p?<?.05) and child’s hostility (F _{(1, 26)}?=?9.220, p?<?.001). Maternal modeling and intentional scaffolding as well as perceptions of her child’s regulatory capacity have a powerful impact on her child’s observed regulation. Results indicate that it is particularly important for mothers of preschoolers to support autonomy while guiding socially appropriate behavior. Interventions that target improving mothers’ negative perceptions of their children, educating on appropriate preschool expectations, and facilitating preschoolers’ mature play may help mothers interact with their children in the ways that foster children’s autonomous emotion regulation.     

"Age of onset of marijuana use and executive function": Correction to Gruber et al. (2011)

Reports an error in "Age of onset of marijuana use and executive function" by Staci A. Gruber, Kelly A. Sagar, Mary Kathryn Dahlgren, Megan Racine and Scott E. Lukas (Psychology of Addictive Behaviors, Advanced Online Publication, Nov 21, 2011, np). Figure 1 should have been presented in color. All versions of this article have been corrected. (The following abstract of the original article appeared in record 2011-27123-001.) Marijuana (MJ) remains the most widely abused illicit substance in the United States, and in recent years, a decline in perceived risk of MJ use has been accompanied by a simultaneous increase in rates of use among adolescents. In this study, the authors hypothesized that chronic MJ smokers would perform cognitive tasks, specifically those that require executive function, more poorly than control subjects and that individuals who started smoking MJ regularly prior to age 16 (early onset) would have more difficulty than those who started after age 16 (late onset). Thirty-four chronic, heavy MJ smokers separated into early and late onset groups, and 28 non-MJ smoking controls completed a battery of neurocognitive measures. As hypothesized, MJ smokers performed more poorly than controls on several measures of executive function. Age of onset analyses revealed that these between-group differences were largely attributed to the early onset group, who were also shown to smoke twice as often and nearly 3 times as much MJ per week relative to the late onset smokers. Age of onset, frequency, and magnitude of MJ use were all shown to impact cognitive performance. Findings suggest that earlier MJ onset is related to poorer cognitive function and increased frequency and magnitude of MJ use relative to later MJ onset. Exposure to MJ during a period of neurodevelopmental vulnerability, such as adolescence, may result in altered brain development and enduring neuropsychological changes. (PsycINFO Database Record (c) 2012 APA, all rights reserved).     

Agnosticism gone awry: Why developmental robotics must commit to an understanding of embodiment and shared intentionality

We argue that developmental robotics, in its integration of developmental psychology and robotics, has the potential to encounter unexpected and unexamined conceptual difficulties. In particular, the various uses of embodiment and shared intentionality single out certain robots and behaviors as more or less relevant for the modeling of social cognition. As these terms have relatively orthogonal histories, there is no account for how their use will interact to shape methodology. We provide a brief discussion of how they may do so. Moreover, theorists often avoid explicit endorsement of some use or another. Although this agnosticism is understandable, we use the model of Dominey and Warneken (2011) as an illustrative example of why it is potentially dangerous. While Dominey and Warneken have succeeded in encouraging theorists to adopt clearer formulations of shared intentionality, their model suffers from important difficulties in interpretation, which, we argue, are a consequence of their uses of embodiment and shared intentionality respectively.