Capitalizing on cortical plasticity: influence of physical activity on cognition and brain function

Given the aging populations in many countries throughout the world, there is an increasing interest in lifestyle factors and interventions that will enhance the cognitive vitality of older adults and reduce the risk for age-related neurological disorders, such as Alzheimer's disease. In this review, we evaluate the hypothesis that physical activity and exercise might serve to protect, and also enhance, cognitive and brain function across the adult lifespan. To this end, we critically review three separate literatures that have examined the influence of physical activity and exercise on cognition, brain function and brain structure of adults, including epidemiological or prospective observational studies, randomized human clinical interventions and non-human animal studies. We suggest that this literature supports the claim that physical activity enhances cognitive and brain function, and protects against the development of neurodegenerative diseases. We discuss future directions to address currently unresolved questions, such as interactions between multiple lifestyle factors on offsetting or protecting against cognitive and neural decline, and conclude that physical activity is an inexpensive treatment that could have substantial preventative and restorative properties for cognitive and brain function.     

Investigation of ethnic differences in body image between Hispanic/biethnic-Hispanic and non-Hispanic White preadolescent girls

The extent to which the construct of body image is measurement invariant across ethnic groups is an important consideration for studies examining ethnic differences and characteristics that influence body image disturbances. However, the literature examining the body image construct as a function of ethnic group membership is limited. The primary aim of this study was to investigate whether Hispanic/biethnic-Hispanic and non-Hispanic White preadolescent girls (aged 8 through 12 years old; N = 141) had fundamentally different conceptualizations of body image in a low to low/middle socioeconomic status school-based sample. Our findings suggest that the measurement construct of body image was similar and relatively stable for Hispanic/biethnic-Hispanic and non-Hispanic White preadolescent girls. In addition, the body image construct was predictably related to disordered eating symptoms in both groups, with different dimensions of body image differentially predictive by ethnic group. Overall, body image appears to be a meaningful construct with similar measurement meanings across Hispanic/biethnic-Hispanic and non-Hispanic White ethnic groups.     

On the Christian in Christian bioethics.

What is Christian about Christian bioethics? And is an authentically Christian bioethics a practical possibility in the world in which we find ourselves? In my essay I argue that personhood and the personal are so fundamental to the Christian understanding of our humanity that body, soul, and spirit are probably best understood as the components of a triune (as opposed to dual) aspect theory of personhood. To confess to a Christian bioethics is to admit that Christians cannot pretend fully to understand either cures or their meaning. However effective and "knowledge-based" contemporary medical interventions are, a Christian must humbly and honestly confess a lack of complete knowledge on both levels. At the same time, a Christian bioethicist must express a total personal commitment to Christian Faith.     

Explaining Away Excellence: The Biased Assault on Private-School Research

Research favoring private education runs counter to the agenda of some researchers and policy makers. Consequently, the ameliorative role of private school is apt to be explained away on methodological grounds. Dr. Erickson offers reasons for the effectiveness of private education beyond what can be accounted for by skimming superior students. Moreover, Dr. Erickson suggests how these explanatory features can enlighten all education—public education included.     

How do rhesus monkeys (<Emphasis Type="Italic">Macaca mulatta</Emphasis>) scan faces in a visual paired comparison task?

When novel and familiar faces are viewed simultaneously, humans and monkeys show a preference for looking at the novel face. The facial features attended to in familiar and novel faces, were determined by analyzing the visual exploration patterns, or scanpaths, of four monkeys performing a visual paired comparison task. In this task, the viewer was first familiarized with an image and then it was presented simultaneously with a novel and the familiar image. A looking preference for the novel image indicated that the viewer recognized the familiar image and hence differentiates between the familiar and the novel images. Scanpaths and relative looking preference were compared for four types of images: (1) familiar and novel objects, (2) familiar and novel monkey faces with neutral expressions, (3) familiar and novel inverted monkey faces, and (4) faces from the same monkey with different facial expressions. Looking time was significantly longer for the novel face, whether it was neutral, expressing an emotion, or inverted. Monkeys did not show a preference, or an aversion, for looking at aggressive or affiliative facial expressions. The analysis of scanpaths indicated that the eyes were the most explored facial feature in all faces. When faces expressed emotions such as a fear grimace, then monkeys scanned features of the face, which contributed to the uniqueness of the expression. Inverted facial images were scanned similarly to upright images. Precise measurement of eye movements during the visual paired comparison task, allowed a novel and more quantitative assessment of the perceptual processes involved the spontaneous visual exploration of faces and facial expressions. These studies indicate that non-human primates carry out the visual analysis of complex images such as faces in a characteristic and quantifiable manner.     

Consequences of organizational justice expectations in a selection system

This study examined several consequences of applicants' expectations of organizational justice at multiple stages in a selection process. The authors assessed the justice expectations of 1,832 job applicants prior to their participation in a testing process and examined how these expectations influenced their pretest attitudes and intentions as well as their perceptions of the testing process. Results revealed that applicants with higher expectations of justice reported higher levels of pretest motivation and more positive job acceptance and recommendation intentions. Justice expectations were also positively related to applicants' perceptions of justice in the testing process. Results provided some evidence that justice expectations have a moderating influence, such that justice perceptions have a greater influence on applicants' affective and cognitive states when expectations of justice are high. The theoretical and practical implications of these findings are discussed in the context of research on organizational justice and applicant perceptions.     

Involvement of 5-HT1A receptors in animal tests of anxiety and depression: evidence from genetic models

Clinical studies have suggested the involvement of 5-HT1A receptors in anxiety and depressive disorders because partial 5-HT1A receptor agonists such as buspirone are therapeutic. The present review considers evidence from genetic animal models that support a role for 5-HT1A receptors in anxiety-like and depressed-like behavior in animals. Selective breeding for differential hypothermic responses to a selective 5-HT1A receptor agonist led to the development of the high DPAT sensitive (HDS) and low DPAT sensitive (LDS) lines of rats. The HDS rats differ from the LDS rats on several behavioral measures reflective of anxiety or depression, including reduced social interaction, reduced responding in a conflict task and exaggerated immobility in the forced swim test. However, they do not differ from the LDS rats in the elevated plus maze task, which is a commonly used test of anxiety. Nor do the HDS rats exhibit a typical anxiogenic response to the hippocampal administration of the 5-HT1A agonist. Although the HDS rats do exhibit elevations in 5-HT1A receptors in regions of the limbic cortex, it is not clear whether these increases account for the behavioral differences. Paradoxically, 5-HT1A receptor knockout mice also exhibit anxiety-like behavior in the plus maze, open field and conflict tests compared to wild type mice. However, the knockouts exhibited less immobility in the forced swim test than wild type control mice. Recent studies using selective regional reinstatement of the receptor have implicated the postsynaptic 5-HT1A receptors in these changes in anxiety-like behavior. Thus, preliminary evidence from two different types of genetic animal models suggests that anxiety-like behavior can arise if the 5-HT1A receptor function is eliminated or overexpressed. Further study with additional tests of anxiety are needed to confirm this intriguing relationship.     

Latent structure of anxiety: taxometric exploration

Taxometrics is a statistical tool that can be used to discern categories from continua. Taxometric analyses (MAXCOV and MAXEIG) were conducted in a large nonclinical sample (N=1,215) to determine whether extreme anxiety forms a distinct psychopathological category, an anxiety taxon. Anxiety was operationalized with self-report measures of subjective anxiety, anxious cognitive style, physiological arousal, and anxiety-related impairment. Procedures consistently identified a taxon with a prevalence of approximately 11%. Examination of the taxon's convergent and discriminant validity revealed that it reflects general distress rather than physiological arousal. Taxon membership showed some evidence of incremental validity.     

Memory enhancement by a semantically unrelated emotional arousal source induced after learning

It has been well established that moderate physiological or emotional arousal modulates memory. However, there is some controversy about whether the source of arousal must be semantically related to the information to be remembered. To test this idea, 35 healthy young adult participants learned a list of common nouns and afterward viewed a semantically unrelated, neutral or emotionally arousing videotape. The tape was shown after learning to prevent arousal effects on encoding or attention, instead influencing memory consolidation. Heart rate increase was significantly greater in the arousal group, and negative affect was significantly less reported in the non-arousal group after the video. The arousal group remembered significantly more words than the non-arousal group at both 30 min and 24 h delays, despite comparable group memory performance prior to the arousal manipulation. These results demonstrate that emotional arousal, even from an unrelated source, is capable of modulating memory consolidation. Potential reasons for contradictory findings in some previous studies, such as the timing of "delayed" memory tests, are discussed.     

Inference and classification learning of abstract coherent categories

Category learning research has primarily focused on how people learn to classify items using simple observable features. However, classification is only 1 way to learn categories. In addition, many concepts have an underlying coherence that explains the featural similarity among exemplars, such as abstract coherent concepts whose instances differ greatly on their observable features. In 3 experiments, the authors investigated how abstract coherent categories are acquired through 2 common means of category learning, classification and inference. Because inference promotes more focus on within-category information than does classification, they hypothesized that inference learning would lead to a better understanding of the underlying coherence of abstract coherent categories. All 3 experiments support this prediction.