Advances in Cognitive Sciences
Year:2007 | Volume:8 | Issue:4 (32)|Papers Count:11

Objective: Ventral Tegmental Area is the main center for reward. In this study the effects of intra-ventral tegmental area (VTA) injections of muscarinic acetylcholine receptor agonists and antagonists on morphine-induced conditioned place preference (CPP) were investigated.Method: The cannulas were implanted (bilaterally) in the VTA by Stereotaxic instrument in Wistar rats. All animals were allowed one week to recover before CPP. Unbiased CPP was induced by carrying out a five day schedule comprised of preconditioning, conditioning and testing phases.Results: Injections of different doses of morphine induced a significant dose-dependent CPP. Intra-VT A injection of an anticholinesterase, physostigmine with an ineffective dose of morphine elicited a significant CPP in a dose dependent method. Intra-VTA administration of muscarinic acetylcholine receptor antagonist, atropine inhibited both morphine-induced place preference and the reinforced response induced by physostigmine. The injection of physostigmine alone into the VTA produced a significant place aversion; whereas atropine did not have such an effect. High doses of physostigmine or atropine alone as well as the simultaneous injection of atropine and physostigmine with an ineffective dose of morphine decreased locomotor activity.Conclusion: The muscarinic acetylcholine receptors in the VTA have a critical role in the rewarding effects of morphine.

Objective: This study was aimed to assess the effects of a GABAA receptor agonist (muscimol) and an antagonist (bicuculline) on morphine-induced locomtor sensitization in male mice.Method: 400 mice were cannulated by stereotaxy and made ready for injection. The program was performed in nine days and three stages. First, sensitization with medication was done in three days. Then for five deys mice did not receive any drugs, and finaly test was executed. Locomotor activity of the animals was registered for a period of 20 minutes after words. The locomtor behavioral response of a morphine challenge dose (5 mg/kg, s.c.) given on day nine was enhanced in mice pretreated with morphine (7.5, 15 and 30 mg/kg/day). Data were analysed by analysis of variance and Tukey's post hoc.Results: subcutaneous injection of morphine (10, 20, 30, and 40, mg/kg) significantly increased the locomotor activity of the animals in a dose-dependent manner. Increase of locomotor activity in the mice with morphine pre-treatment (7.5, 15, and, 30 mg/kg) was a marker of sensitization. hree days administration of muscimol (0.025, 0.05,0.1, and 0.2 mg/mouse/day) significantly decreased morphine-induced motor stimulation (5mg/kg) both in the presence or absence of morphine. On the other hand 3-days pre-treatment with bicuculline (0.25, 0.5, and 1 mg/mouse/day) with or without the prescence of morphine decreased the response of injection of muscimol (0.1 mg/mouse/day) to induction of locomotor activity by morphine (S mg/kg). Co-administration of bicuculline (0.1, 0.2, and 0.5 mg/mouse) and muscimol (0.1 mg/mouse) significantly decreased the morphine- induced locomotor activity in the animals pre-treated with saline or morphine (15 mg/kg).Conclusion: The results indicate that GABAA receptors may be involved in development and expression of morphine –induced sensitization.

Objective: In this research the effect of attention and levels-of-processing on the function of memory and the retrieval of words with explicit and implicit memory, in two different states, where the subject of study was either interesting or not interesting for the students was studied.Method: This was an experimental study and was carried out individually using a computerized measuring tool on 160 students. Data were analyzed using three-way ANOVA.Results: Focused attention, interest in the subject of study, and deep processing brought about the highest degree of explicit memory function. In contrast, shallow processing, divided attention, and lack of interest led to the lowest function of explicit memory.Conclusion: The effects of variables on explicit and implicit memory were different in some aspects. Interest, attention, and level of processing ranked first to third respectively in their effects on explicit memory; and interest and attention ranked first and second respectively in their effect on implicit memory. The level- of- processing did not have a significant effect on implicit memory.

Objective: The study was designed to evaluate the validity of Farsi version of Strenghts and Oifficulties Questionnaire (SDQ).Method: Validity of the parent and teacher versions of SDQ was assessed in a community sample of Iranian school children aged 6 to 11 years (n=600). The results of SDQ were compared to the diagnoses made by child and adolescent psychiatrist and K-SADS diagnostic interview.Results: Scores of the parent and teacher versions of SDQ were positively correlated. Comparing the scores of hyperactivity and total difficulties of psychiatric diagnoses showed that SDQ has an acceptable validity. Calculated cut off points were comparable to the results of other countries.Conclusion: Farsi version of SDQ has good psychometric properties, and could be used for screening of Iranian children with behavioral and emotional problems. A similar study with SDQ on adolescents is recommended.

Objective: This study compared the academic stressors and the reactions to them in female and male students using Gadzella's Life Stress Inventory.Method: The sample included 166 male and 251 female students. Five categories of academic stressors (Le. frustrations, conflicts, pressures, changes, and self-imposed) and four categories describing reactions to these stressors (Le. physiological, emotional, behavioral, and cognitive) were examined.Results: Female students reported higher frustrations, pressures, changes, self-imposed stressors and greater physiological, emotional, behavioral and cognitive reactions to stressors than male students; while males reported higher conflict stressors than females. The MANCOV A yielded a significant main effect, adjusted for age. Also, respondent's gender and stressors emerged as the two strongest predictors of their physiological, emotional, behavioral and cognitive reactions to stressors in the hierarchical regression analysis. All the five stressors attained statistical significance in the model. These variables explained 32% of variance in physiological reaction, 42% for emotional reaction, 25% for behavioral and 16% for cognitive reactions. Conclusion: The findings emphasize on the need to recognize gender differences in stress management. Implications for mental health professionals are discussed.

Objective: Attention Deficit Hyperactivity Disorder (ADHD) is a common child psychiatric disorder, which regarding the young population of Iran, can cause significant disability. From among health measures, DALY (Disability Adjusted Life Years) is an efficient summary measure for estimation of health problems in various disorders and provides the possibility of comparison between burdens of various disorders.Method: The DALY for ADHD was calculated on the basis of information related to incidence, prevalence and case fatality rate, using demographic information in 2003. To assess the concordance between raw data and to carry out the final analysis DisMod II software was used, and finally YLD (Years Lived with Disability) was calculated as a measure equal to DALY.Results: YLD was 15.7 in males and 6.7 in females. Total DALYs in both sexes and in all ages were 22.4. In the sensitivity analysis with assumption of no remission of the disease in adulthood, DALY was 31.9 indicating that the mentioned DAL Y of 22.4 must be considered as the minimum estimation of burden.Discussion: It seems that ADHD causes noticeable disability in all age groups in general, and the children and youth in particular.

Neurocognitive executive functions play a crucial role in guiding and controlling behavior. Neurocognitive functions include various components such as self-regulation, working memory, time perception and internal language. Executive Functions (EFs) develop along the course of the child's development and gradually help the child to execute harder and more complex tasks. The precise evaluation of EFs will help to get a better understanding about the child's development and developmental disorders. EP assessment could be carried out by both formal and informal methods; and in this context the assessment of unstructured situations is emphasized. Executive dysfunction can have significant consequences for the social, educational and emotional function of the child. This article studies findings about executive dysfunctions in developmental disorders such as attention deficit hyperactivity disorder, autism spectrum disorders, acquired or traumatic brain injuries, developmental coordination disorder, learning disorders, conduct disorder, and oppositional defiant disorder. Some guidelines for treatment with regard to executive dysfunctions will be discussed thereafter.

This article aimed to review recent research findings on cognitive aspects of obsessive compulsive disorder (OCD), to pave the way for future studies. Last three decades has witnessed a great progress in understanding the role of cognitions in forming, persistence and treatment of many psychiatric disorders including OCD. Cognitive variables of OCD emphasize on the interpretations of both the occurrence and the content of intrusive thoughts. Many questions regarding intrusive and unwanted thoughts, impulses, and images have remained unanswered, in clinical and nonclinical populations, including their formation, functions, consequences and their treatment. How an intrusive thought is converted to an obsession is one of the important subjects in OCD literature. The cognitive model implies that the patients with OCD over-value their thoughts and impulses. It seems that these impulses, thoughts, and images are formed as a result of dysfunctional beliefs. Several dysfunctional beliefs such as over-responsibility, thoughts importance, thoughts control, responsibility and threat over-estimation and perfectionism could play an important role in development of the disorder. Many studies have shown the relation between cognitive characteristics and OCD. However, a certain conclusion about the specific fields cannot be drawn. The wide diversity of the findings is a problem in this area.