Long-term memory survives nerve injury and the subsequent regeneration process

A three-neuron network (a central pattern generator [CPG]) is both sufficient and necessary to generate aerial respiratory behavior in the pond snail, Lymnaea stagnalis. Aerial respiratory behavior is abolished following a specific nerve crush that results in axotomy to one of the three CPG neurons, RPeD1. Functional regeneration of the crushed neurite occurs within 10 days, allowing aerial respiratory behavior to be restored. Functional regeneration does not occur if the connective is cut rather than crushed. In unaxotomized snails, aerial respiratory behavior can be operantly conditioned, and following memory consolidation, long-term memory (LTM) persists for at least 2 weeks. We used the Lymnaea model system to determine (1) If in naive animals axotomy and the subsequent regeneration result in a nervous system that is competent to mediate associative learning and LTM, and (2) if LTM survives RPeD1 axotomy and the subsequent regenerative process. We show here that (1) A regenerated nervous system is competent to mediate associative memory and LTM, and (2) LTM survives axotomy and the subsequent regenerative process.     

Emergence of a cue strategy preference on the water maze task in aged C57B6 x SJL F1 hybrid mice

The effects of age on cue learning, spatial reference memory, and strategy preference were assessed in B6 × SJL F1 mice by using the Morris water maze. This mouse strain is of particular interest because it is the background strain for a common transgenic model of Alzheimer's disease, the Tg2576 mouse, which develops plaques and other neurobiological markers of pathology beginning at 8 mo and increasing in severity with advanced age. In the current study, 12- and 23-mo-old C57B6 × SJL F1 mice were serially trained in cue and place versions of the Morris water maze task. At the completion of training, mice received a strategy probe test in which place (hidden) and cue (visible) strategies were in competition. Cue and spatial learning ability was maintained between 12 and 23 mo of age; however, on the strategy preference probe test, the 23-mo-old mice exhibited a significant bias toward the selection of a cue strategy. There was no relationship between strategy preference in the probe test and spatial learning ability, but the 23-mo-old mice did exhibit a strong trend toward shorter latencies during visible platform training, possibly reflecting the enhanced function of striatal-based neural systems in aging. These data demonstrate that 23-mo-old C57B6 × SJL F1 mice are capable of effective place learning, but if a place strategy is pitted against the use of a cue strategy, the use of a cue strategy predominates in the aged mice. The strategy preference observed here may reflect an emergence of differential processing in underlying brain circuitry with age in the B6 × SJL F1 mouse strain.     

A cross-modal interference effect in grasping objects

The aim of the present paper was to investigate how the kinematics of a hand reaching toward a visual target would be influenced by haptic and proprioceptive input from an unseen distractor actively grasped in the other, nonreaching hand. The main results were that the amplitude of maximum grip aperture was smaller and the time to maximum grip aperture was earlier when the distractor was smaller than the target. The interference effect from the distractor was similar for both hands as they reached. Furthermore, results from a vibrating-distractor condition for passive tactile input revealed that the interference effects were evident only when the distractor was actively grasped. We suggest that neural processing of proprioceptive and tactile information relevant to distractor size produced the observed interference effects. We also emphasize the importance of active manipulation of the distractor stimulus in eliciting such interference effects.     

A review of the biological bases of ADHD: what have we learned from imaging studies?

Attention Deficit Hyperactivity Disorder (ADHD) is a common and impairing neuropsychiatric disorder with onset at preschool age. Although a significant amount of progress has been made investigating the neurobiology of this disorder, its precise etiology still remains unclear. Converging evidence from studies of the neuropharmacology, genetics, neuropsychology, and neuroimaging of ADHD imply the involvement of fronto-striatal circuitry in ADHD. However, while it does appear that poor inhibitory control and the deficits in fronto-striatal circuitry associated with it are central, there is evidence to suggest that more posterior cerebral areas are also implicated in this disorder. Anatomical studies suggest widespread reductions in volume throughout the cerebrum and cerebellum, while functional imaging studies suggest that affected individuals activate more diffuse areas than controls during the performance of cognitive tasks. The future impact of new MR imaging methodologies on the field is discussed.     

Generalized eta and omega squared statistics: measures of effect size for some common research designs

The editorial policies of several prominent educational and psychological journals require that researchers report some measure of effect size along with tests for statistical significance. In analysis of variance contexts, this requirement might be met by using eta squared or omega squared statistics. Current procedures for computing these measures of effect often do not consider the effect that design features of the study have on the size of these statistics. Because research-design features can have a large effect on the estimated proportion of explained variance, the use of partial eta or omega squared can be misleading. The present article provides formulas for computing generalized eta and omega squared statistics, which provide estimates of effect size that are comparable across a variety of research designs.     

Pavlov in America: a heterodox approach to the study of his influence

This work presents a critical analysis of Pavlov's influence that goes beyond the conventional view: that which reduces his influence in American psychology to the behaviorism of Watson and Hull. In order to understand the nature of the Russian physiologist's influence in American psychology, we propose a distinction between three approaches to it: 1) the symbolic approach, on representing a model of the possibility of constructing an objective psychology; 2) the methodological approach, given the importance of the technique of conditional reflexes; and 3) the theoretical approach, which is derived from his theory of higher nervous activity. This perspective permits us to suggest that most of Pavlov's influence on behaviorism was of a symbolic and methodological nature--though the methodological influence also reached other authors that did not belong to the behaviorist traditions, as was the case of Mateer. As far as the theoretical influence is concerned, our work proposes that it is more visible in authors such as Gantt and Liddell, or even in authors such as Boldirev, Director of the Pavlovian Laboratory at the Battle Creek Sanitarium in Michigan. The case of Gantt is especially interesting because, in addition to his important contributions, he played an essential role in the foundation of the Pavlovian Society, and the journal Conditional Reflex. What our work proposes is that to understand the nature of Pavlov's influence in American psychology it is necessary to take into account the very characteristics of that psychology: its pragmatic interests, its methodological rigor, the dominant systems of neo-behavioral theory and the changes that occurred after the Second World War.     

Social psychology of mental health: the social structure and personality perspective

Previous research has revealed a persistent association between social structure and mental health. However, most researchers have focused only on the psychological and psychosocial aspects of that relationship. The present paper indicates the need to include the social and structural bases of distress in our theoretical models. Starting from a general social and psychological model, our research considered the role of several social, environmental, and structural variables (social position, social stressors, and social integration), psychological factors (self-esteem), and psychosocial variables (perceived social support). The theoretical model was tested working with a group of Spanish participants (N = 401) that covered a range of social positions. The results obtained using structural equation modeling support our model, showing the relevant role played by psychosocial, psychological and social, and structural factors. Implications for theory and intervention are discussed.     

Prevalence of Child and Adolescent Exposure to Community Violence

Emerging as one of the most significant health issues facing American youth today, child and adolescent exposure to community violence has generated much interest across multiple disciplines. Most research to date has focused on documenting the prevalence of community violence and the emotional and behavioral ramifications. This paper provides an overview of the current literature regarding prevalence of youth exposure to community violence, and identifies those areas where further research is warranted. In addition to examining overall rates of community violence exposure, this paper reviews the prevalence of different types of community violence, such as weapon use, physical aggression, and crime-related events. Predictors of community violence exposure, including gender, age, race, socioeconomic status, behavior patterns, and geography, are discussed.     

Are exercise social-cognitive factors and behaviours different for adults with diabetes? A randomized community sample

Exercise plays a key role in the prevention and delay of the onset of Type 2 diabetes and in the management of this disorder. To determine if there are differences in key social-cognitive determinants of exercise and self-reported physical activity levels between adults with diabetes and those without the condition, a random selected sample of adults was surveyed. A telephone interview assessed physical activity behaviour and key social-cognitive constructs from major health behaviour change theories/models. The mean energy expenditure was not significantly different between the diabetes (n?=?46) and the non-diabetes (n?=?1556) groups. The diabetes group reported significantly lower scores for self-efficacy and perceived behavioural control, but higher for fear of, and vulnerability to, general health and cardiovascular disease threat. The data suggest that it may not be necessary to promote health threat messages, as threat is already high for this diabetes population and studies have shown that excess threat does not promote recommended exercise and health behaviours. Instead, the low levels of self-efficacy and perceived behavioural control among those with diabetes emphasize the importance of designing specific strategies (e.g., skills, incremental success) to increase their self-confidence in undertaking physical activity.     

Causal attributions and blame: associations with mothers' adjustment to the birth of a child with Down syndrome

The main purpose of this study is to explore the associations between causal attributions to others, blaming others and mothers' adjustment to the birth of a child with Down syndrome (DS). Participants (n?=?214) rated causal attributions to others and blaming others, and completed five measures of adjustment: anger, anxiety, depression, parenting stress, and attitudes towards the child. The adjustment of three groups of mothers was compared: (i) those who made no attributions to others (ii) those who made causal attributions but did not blame, and (iii) those who blamed others. Four years after the births of their children with DS, 16% of mothers blamed others and 17% made causal attributions but did not blame others for this outcome. Those who blamed others had higher levels of anger, anxiety, depression, parenting stress and more negative attitudes towards their children with DS than did those who made causal attributions but did not blame, and those who made who made no attributions to others. The adjustment of the latter two groups did not differ. Investigating blame rather than causal attributions may be a more fruitful area for future research aimed at understanding and facilitating adjustment to illness and other negative life events.