The biochemical bases of the placebo effect

A great variety of medical conditions are subject to the placebo effect. Although there is mounting evidence to suggest that the placebo effect is related to the expectation of clinical benefit, little is still known about the biochemical bases underlying placebo responses. Positron emission tomography studies have recently shown that the placebo effect in Parkinson’s disease, pain, and depression is related to the activation of the limbic circuitry. The observation that placebo administration induces the release of dopamine in the ventral striatum of patients with Parkinson’s disease suggests a link between the placebo effect and reward mechanisms. In addition to Parkinson’s disease, the placebo-reward model may also apply to other disorders. However, the relative contribution of the different neurotransmitters and neuropeptides that are known to be involved in modulating the activity of the limbic system may be disease-specific. Thus, while the placebo-induced clinical benefit observed in Parkinson’s disease would mostly reflect the release of dopamine in the dorsal striatum, the activation of opioid and serotonin pathways could be particularly implicated in mediating placebo responses encountered in pain and depression, respectively. An earlier version of this paper was presented at an international conference, “Placebo: Its Action and Place in Health Research Today,” held in Warsaw, Poland on 12–13 April, 2003.     

Are responsibility attitudes related to obsessive-compulsive symptoms in schoolchildren?

In spite of a growth in cognitive conceptualizations of obsessive-compulsive symptoms, relatively little has been done to extend such concepts to childhood. This study investigated the relationship between responsibility attitudes and obsessive-compulsive symptoms in normal children. A measure of responsibility attitudes in children was constructed on the basis of Salkovskis' Responsibility Attitudes Scale. This measure (Responsibility Attitudes Scale for Children) was administered together with the Leyton Obsessive Inventory Child Version and the Children's Depression Inventory to a sample of two hundred and two 10-14-year-old schoolchildren in Iceland. The responsibility measure correlated moderately and similarly with the Leyton Obsessive Inventory Child Version and the Children's Depression Inventory. In a hierarchical regression analysis predicting Leyton Obsessive Inventory Child Version scores, age and gender were entered in the equation first, followed by Children's Depression Inventory scores and, finally, Responsibility Attitudes Scale for Children scores. It was shown that Responsibility Attitudes Scale for Children scores added significantly to the prediction of Leyton Obsessive Inventory Child Version over and above the other variables. It is concluded that the study of the role of responsibility attitudes in children's obsessive-compulsive symptoms is at least promising.     

Preliminary validation of a Spanish version of the Sport Motivation Scale

The Sport Motivation Scale was developed in French and later translated into English and validated by Pelletier, et al. in 1995. It is based on the principles of self-determination theory. In this study the scale was translated into Spanish to assess and validate it for a sample of 275 athletes (78 women and 197 men) whose mean age was 21.3 yr. (SD=3.8) and who represented eight sports (track and field, tennis, swimming, waterpolo, soccer, basketball, handball, and volleyball). The Spanish version showed satisfactory internal consistency (Cronbach alpha of .70 to .80) and temporal stability (test-retest r = .69 to .74) over a 4-wk. period. A confirmatory factor analysis partially supported the seven-factor structure. Correlations among the subscales indicated a simplex pattern supporting the construct validity of the scale. Sex differences were found. Taken together, these findings support use of the Spanish version for assessment of motivation in sport.     

Visual search strategies of experienced and nonexperienced swimming coaches

The aim of this study consists of the application of an experimental protocol that allows information to be obtained about the visual search strategies elaborated by swimming coaches. 16 swimming coaches participated. The Experienced group (n=8) had 16.1 yr. (SD=8.2) of coaching experience and at least five years of experience in underwater vision. The Nonexperienced group in underwater vision (n= 8) had 4.2 yr. (SD= 4.0) of coaching experience. Participants were tested in a laboratory environment using a video-projected sample of the crawl stroke of an elite swimmer. This work discusses the main areas of the swimmer's body used by coaches to identify and analyse errors in technique from overhead and underwater perspectives. In front-underwater videos, body roll and mid-water were the locations of the display with higher percentages of fixation time. In the side-underwater slow videos, the upper body was the location with higher percentages of visual fixation time and was used to detect the low elbow fault. Side-overhead takes were not the best perspectives to pick up information directly about performance of the arms; coaches attended to the head as a reference for their visual search. The observation and technical analysis of the hands and arms were facilitated by an underwater perspective. Visual fixation on the elbow served as a reference to identify errors in the upper body. The side-underwater perspective may be an adequate way to identify correct knee angles in leg kicking and the alignment of a swimmer's body and leg actions.     

Contextual interference in learning precision skills

This research studied the effect of different organisations of practice (blocked and random) on the learning of three different types of throwing. 35 male students practiced three precise throws for 3 wk. Initially the subjects were separated into two groups who trained under different conditions of practice (blocked and random). All subjects improved significantly from initial performance, with both blocked practice and random practice. At the end of acquisition no differences were found between the groups. No significant differences were found on retention tests carried out 48 hr., 4 wk., and 8 wk. after the training period.     

The role of cortical cholinergic pre- and post-synaptic receptors in taste memory formation

A number of studies have implicated cholinergic activity in the mediation of learning and memory processes. However, the specific role of muscarinic receptors in memory formation mechanisms is less known. The aim of the present study is to evaluate the effects of muscarinic antagonist M2 presynaptic receptor, AFDX-116 (0.5mM) and M1 and M3 post-synaptic receptor pirenzepine (100mM), as well as a non-selective muscarinic antagonist, scopolamine (136mM), in the insular cortex (IC) during acquisition and retrieval of conditioned taste aversion (CTA). In addition, we evaluate the effects of those antagonists in cortical ACh release by in vivo microdialysis and the effects on the induction of in vivo LTP in the BLA-IC projection. The results showed that the cortical microinjections of scopolamine and pirenzepine, but not AFDX-116, produced significant disruption in the acquisition of CTA, without effects during retrieval. Microinjections of scopolamine and AFDX-116 produced significant cortical ACh release, while infusions of pirenzepine did not produce any release. Application of scopolamine and pirenzepine diminished induction of LTP in the BLA-IC projection, but not AFDX-116, as compared with vehicle. The induction of BLA-CI LTP seems to be modulated by post-synaptic muscarinic acetylcholine receptors and not by pre-synaptic muscarinic receptors. These results suggest a differential involvement of cholinergic receptors during acquisition and retrieval of aversive memory formation, as well as a differential role of muscarinic receptors in the biochemical and electrophysiological processes that may underlay aversive memory.     

Evaluation of violent behaviors in secondary school

School harassment, or bullying, is a term that for being so frequent already forms a part of our vocabulary. In the present work one presents a new instrument of evaluation of the violence that happens in the school centers. The Questionnaire of School Violence (CUVE) has been elaborated and, later, applied to a sample of 1637 teenagers of seven centers of Secondary Obligatory Education (public and compound). The CUVE evaluates in a trustworthy way five dimensions of the school violence: a) physical indirect violence on the part of the student body; b) verbal violence of the student body towards companions; c) physical direct violence between (among) pupils; d) verbal violence of the student body towards the professorship; and e) violence of the professorship towards the student body.     

A new scale for the assessment of the quality of hospitality services

In the last 20 years the services sector has experienced a highly significant growth, being currently one of the most important economic sectors in our country. Inside the touristic sector, a strong competence has being experienced among the lodging and restoration establishments. In a scenario characterized by competitiveness, the bet for quality represents a difficult competitive advantage to surpass (García-Buedes, 2001). The objective of this study is to carry out an approach to the evaluation of the perceived quality of the restaurants. As a result of bibliographic revision, and also a first approach of a qualitative nature, we started from a scale of 31 items that included 5 dimensions: access, personal, service, product and installations. The results obtained applying the questionnaire to more than 2400 clients of 180 establishments of Santiago de Compostela and region, by means of structured interviews, confirmed that not all these dimensions had the same importance as predictors of customer satisfaction. Specifically, the product emerges as the most important dimension. Likewise, the elimination of the dimension service and a more exhaustive selection of the items, based on psychometric criteria, has permitted to define a brief scale, consisting of only 15 items, which makes it very attractive as a management tool. The final scale proposed to evaluate the perceived quality in the restaurant sector includes four fundamental and non-independent dimensions. These are, ordered by importance: product, personal, installations and access.     

Amnesic effect of GMP depends on its conversion to guanosine

Extracellular guanine-based purines, namely the nucleotides GTP, GDP, GMP and the nucleoside guanosine, exert important neuroprotective and neuromodulator roles in the central nervous system, which may be related to inhibition of the glutamatergic neurotransmission activity. In this study, we investigated GMP effects on mice inhibitory avoidance performance and the dependence on its conversion to guanosine for such effect, by using the ecto-5'-nucleotidase specific inhibitor AOPCP. We also investigated if this conversion occurs in the central nervous system or peripherally, and if guanosine and GMP affect nociception by the tail-flick test. I.p. GMP or guanosine (7.5 mg/kg) or i.c.v. GMP (480 nmol) pretraining administration was amnesic for the inhibitory avoidance task. I.c.v. AOPCP (1 nmol) administration completely reversed the amnesic effect of i.c.v. GMP, but not of i.p. GMP, indicating that peripheral conversion of GMP to guanosine is probably relevant to this effect. AOPCP alone did not interfere with the performance. Furthermore, tail-flick measurement was unaffected by i.p. GMP and guanosine, suggesting that the amnesic effect of both purines was not due to some antinociceptive effect against the footshock used in the task. All these data together, in accordance to those previously observed in studies involving glutamate uptake and seizures reinforce the idea that guanosine is the specific extracellular guanine-based purines effector and indicate that its conversion occurs not only in the central nervous system but also peripherally.