Metyrapone and fluoxetine suppress enduring behavioral but not cardiac effects of subchronic stress in rats

In humans, chronic stressors have long been recognized as potential causes for cardiac dysregulation. Despite this, the underlying mechanistic links responsible for this association are still poorly understood. The purpose of this study was to determine whether exposure to a paradigm of subchronic stress can provoke enduring changes on the heart rate of experimental rats and, if so, to reveal the autonomic and neural mechanisms that mediate these effects. The study was conducted on adult male Sprague-Dawley rats instrumented for telemetric recording of heart rate and locomotor activity. Animals were submitted to a subchronic stress protocol, consisting of a 1-h foot shock session on five consecutive days. Heart rate and locomotor activity were recorded continuously for 3 days before and for 6 days after the subchronic stress period. Subchronic foot shock produced significant and enduring reduction in heart rate both during the dark/active [Δ= −23 ± 3 beats per minute (bpm)] and light/inactive (Δ= −20 ± 3 bpm) phases of the circadian cycle, and a reduction in locomotor activity during the dark/active phase [Δ= −54 ± 6 counts per hour (cph)]. The bradycardic effect of subchronic stress was not related to a reduced locomotion. Selective sympathetic (atenolol) and vagal (methyl-scopolamine) blockades were performed to reveal which autonomic component was responsible for this effect. We found that the fall in heart rate persisted after subchronic stress in animals treated with atenolol (active phase Δ= −16 ± 3 bpm, inactive phase Δ= −19 ± 2 bpm), whereas vagal blockade with scopolamine transiently prevented this effect, suggesting that the bradycardia following subchronic stress was predominantly vagally mediated. Fluoxetine (selective serotonin reuptake inhibitor) and metyrapone (inhibitor of corticosterone synthesis) treatments did not affect heart rate changes but prevented the reduction in locomotion. We conclude that subchronic stress exposure in rats reduces heart rate via a rebound in vagal activation and that this effect is serotonin- and corticosterone-independent.

Tim O'Reilly and web 2.0 : the economics of memetic liberty and control

This article presents an account of the role of Tim O'Reilly, both as an individual and as a corporate entity (O'Reilly Group), in the creation, spread and use of the concept of Web 2.0. It demonstrates that, whatever Web 2.0's current uses to describe variously the technologies, politics, commerce or social meaning of the Internet, it originates as a deliberately open signifier of novel and potential internet development in the mid-2000s. The article argues that O'Reilly has promoted the diversity of the term's meanings and uses - celebrating textual liberties - but has also emphasised the special role that O'Reilly plays in providing the authoritative definition of that term. In essence, O'Reilly profits from this 'control' of the idea of Web 2.0 but that, to enjoy that control O'Reilly must also allow differences in meaning. The article concludes by suggesting that Web 2.0 therefore signifies a new kind of economics that brings together freedom and control in a new way.

Reconceptualizing autism : moving beyond the behavioral to address cause, cure and prevention

Since the publication of Leo Kanner's seminal paper in 1943, there has been essentially no definitive light shed on the cause, prevention or cure of autism. It is our contention that the reason lies, at least in part, with the original psychiatric conceptualization of the condition and the subsequent acceptance of this framework by health professionals ever since. We suggest an urgent revision of autism as a disease state such that its operationalization in major diagnostic systems such as the Diagnostic and Statistical Manual of Mental Disorders and International Classification of Diseases recognizes the biological variables known to be associated with autism.

Can social dancing prevent falls in older adults? a protocol of the Dance, Aging, Cognition,Economics (DAnCE) fall prevention randomised controlled trial

Background:  Falls are one of the most common health problems among older people and pose a major economic burden on health care systems. Exercise is an accepted stand-alone fall prevention strategy particularly if it is balance training or regular participation in Tai chi. Dance shares the ‘holistic’ approach of practices such as Tai chi. It is a complex sensorimotor rhythmic activity integrating multiple physical, cognitive and social elements. Small-scale randomised controlled trials have indicated that diverse dance styles can improve measures of balance and mobility in older people, but none of these studies has examined the effect of dance on falls or cognition. This study aims to determine whether participation in social dancing: i) reduces the number of falls; and ii) improves cognitive functions associated with fall risk in older people.

Methods/design: A single-blind, cluster randomised controlled trial of 12 months duration will be conducted. Approximately 450 participants will be recruited from 24 self-care retirement villages that house at least 60 residents each in Sydney, Australia. Village residents without cognitive impairment and obtain medical clearance will be eligible. After comprehensive baseline measurements including physiological and cognitive tests and self-completed questionnaires, villages will be randomised to intervention sites (ballroom or folk dance) or to a wait-listed control using a computer randomisation method that minimises imbalances between villages based on two baseline fall risk measures. Main outcome measures are falls, prospectively measured, and the Trail Making cognitive function test. Cost-effectiveness and cost-utility analyses will be performed.

Discussion: This study offers a novel approach to balance training for older people. As a community-based approach to fall prevention, dance offers older people an opportunity for greater social engagement, thereby making a major contribution to healthy ageing. Providing diversity in exercise programs targeting seniors recognises the heterogeneity of multicultural populations and may further increase the number of taking part in exercise.

Cognitive behavioral treatment of obsessive compulsive disorder : a broader framework

Obsessive Compulsive Disorder (OCD) is rated as a leading cause of disability by the World Health Organization (1996). OCD is a heterogeneous and complex anxiety disorder characterized by the occurrence of repeated and distressing intrusive thoughts, and compulsive actions that are performed in order to lessen distress or prevent the negative outcome associated with the intrusions. Over the last several decades, cognitive behavioral treatments (CBT) of OCD have dramatically improved the prognosis for the disorder. However, a significant proportion of individuals presenting with OCD may still fail to benefit from treatment. In this paper, we present current CBT treatment models of OCD. We then propose several ways of enhancing CBT for OCD by targeting clients' attachment anxiety and dysfunctional self perceptions.

Neuropsychological changes following cognitive-behavioral treatment of obsessive-compulsive disorder (OCD)

Previous research has suggested that individuals with OCD show compromised performance on tests assessing visuospatial and executive processes. This study aimed to further examine such findings by investigating the relationship between OCD symptom improvement following cognitive-behavioral therapy and changes in neuropsychological performance in individuals with OCD (n = 26), compared to test-retest control participants (n = 10). Successful treatment of OCD led to improvements relative to the control group on neuropsychological tasks measuring spatial working memory. Neuroscientific models of OCD consider such findings to be consistent with possible cortical dysfunction in OCD. However, a significant limitation of the study is in its inability to discount alternative explanations for this finding, such as the influence of changes in beliefs. Implications are discussed.