Advances in Cognitive Sciences
Year:2007 | Volume:9 | Issue:3 (35)|Papers Count:10

Objective: In the present study the effect of histamine sensitization on the retrieval of passive avoidance memory was investigated.Method: One-trail step-down passive avoidance task was used to assess memory in adult male NMRI mice.Results: Post training administration of lithium (10 mg/kg) impaired the memory on the training day, and pre-test administration of lithium prevented the impairment of memory (p<0.001). Sensitization was induced using daily injections of 20 mg/mouse histamine in three consecutive days followed by five drug-free days. The lithium-induced impaired memory was restored better in mice sensitized with histamine than in non-sensitized mice (p<0.01). On the other hand, frequent injection (three days injection followed by five drug free days) of the H1 receptor antagonist pyrilamine (40 mg/mouse), and the H2 receptor antagonist ranitidine (6.25 and 12.5 mg/mouse), prevented the restoration of impaired memory.Conclusion: Histamine sensitization affects memory impairment induced by lithium; therefore, it is postulated that signaling cascade from histamine receptors may mediate the effects of lithium on memory in passive avoidance task.

Objective: To examine the effects of bilateral injections of cholinergic agents into the hippocampal CA1 regions (intra-CA1) on ethanol state-dependent memory in mice.Method: Male NMRI mice (20-30 g) were used in this research. The cannulas were implanted (bilaterally) in the CA1 of dorsal hippocampus by Stereotaxic instrument in animals. All animals were allowed one week to recover before behavioral experiments. A single-trial step-down passive avoidance task was used for the assessment of memory retention.Results: Pre-test administration of ethanol (0.5 and 1 g/kg) induced state-dependent retrieval of the memory acquired under pre-training ethanol (1 g/kg) influence. Pre-test intra-CA1 injection of physostigmine and nicotine improved pre-training ethanol (1 g/kg)-induced retrieval impairment. Moreover, pre-test intra-CA1 administration of physostigmine and nicotine with an ineffective dose of ethanol (0.25 g/kg) significantly restored the retrieval and induced ethanol state-dependent memory. Pre-test intra-CA1, injection of the muscarinic receptor antagonist, atropine or the nicotinic receptor antagonist, mecamylamine along with the intra-peritoneal administration of ethanol (1 g/kg) inhibited ethanol state-dependent memory. Intra-CA1 pre-test administration of physostigmine, atropine, nicotine or mecamylamine alone did not affect memory retention.Conclusion: These findings indicate that the cholinergic system is involved in ethanol state-dependent memory through muscarinic and nicotinic receptors of dorsal hippocampalCA1 regions.

Objective: The aim of this study was to compare the brain imaging characteristic of transsexuals with normal individuals.Method: In this descriptive analytical study 30 person were selected by sequentional sampling in two control and case groups that had the inclusion criteria and did not have the exclusion criteria from patients admitted to Rouzbeh Hospital and forensic medical organization. Demographic information such as height, weight, head circumference and BMI were obtianed and brain MRI performed by 3D FSE method. Collected data were analyzed by Analyze volumetric software (Mayo Foundation, Rochester). Red nucleus, CSF, intradural and paranchima volume and Corpus collasum area were analyzed statisticaly using T-test Pearson correlation coefficient tests.Results: Red nucleus volume difference between case and control groups were significant. Difference of red nucleus, paranchima and IDV volume between male and females were significant too. In addition there was no significant difference in red nucleus volume between male patients and normal females but the difference between female patients and normal males was significant.Conclusion: in this study difference in brain anatomical structure between transsexuals and normal individuals observed. It seems that maybe sometime in the process of development and CSF differentiation in prenatal period and intrauterine life brain anatomical structure changed and does not follow the normal pathway consistent with ones gender.

Objective: Previous studies on ADHD indicate impairments in executive functions including working memory. In addition, there are findings pointing to impairments in visual memory in these children. The objective of this study was to assess visual memory in children with ADHD using neuropsychological tests sensitive to temporal lobe function.Method: In this cross-sectional analytical study, forty one 6-12 year old children with ADHD and normal IQ with no history of drug treatment were compared to 30 normal children matched for sex, age and IQ, using the neuropsychological tests Paired Associated Learning (PAL), Delayed Match to Sample (DMS) and Pattern Recognition Memory (PRM).Results: ADHD children showed poorer performance on PAL than the normal group; significantly higher total errors and tries and significantly lower completed stages was. In DMS the percentage of correct responses in the patient group was significantly lower than the control group and this difference was also significant regarding the percentage of correct responses, total delays, and simultaneous display. The results in PRM test showed that the percentage of correct responses and the delay to correct response was worse in the patient group than in the normal group. However, this difference was not significant.Conclusion: The performance of non-treated ADHD patients in tests sensitive to temporal function in general and visual memory in particular shows some impairment in comparison with the control group.

Objective: The aim of the current research was to study selective attention toward food and body-shape related stimuli in subjects with eating disorder symptoms who had not presented for treatment.Method: 53 female subjects with the symptoms of eating disorders (15 subjects with symptoms of anorexia nervosa, and 38 subjects with symptoms of bulimia nervosa) and 46 normal females aged 14 to 18 were selected and matched on the bases of age, education, and parent education. All subjects responded to the computerized version of the Dot Probe Task (a computerized task for assessing selective attention). The target words in this research were food and body-shape words, which were all matched according to frequency and word length with neutral words. The subjects' reaction times were measured and recorded. A factorial design and ANOVA were employed to analyze the results.Results: Subjects with eating disorder symptoms who had scored high on Eating Attitudes Test (EAT-26) showed attention bias with avoidance from body-shape stimuli, while this bias was not observed for food stimuli.Conclusion: The findings of this research are interpreted in the light of past studies.

Objective: The present study was carried out to compare the type or pattern of stuttering between Farsi stuttering children and adults.Method: 50 stuttering subjects presenting to public and private clinical and educational centers were divided into five age groups of ten subjects (with age ranges of 3-6, 7-9, 10-12, 13-16, and 17 and higher). At least five minutes of spontaneous speech of each subject was recorded and the stuttering pattern of each subject was determined based on the type of words. Data were analyzed using Kruskal-Wallis and Mann-Whitney tests.Results: The dominant pattern of stuttering in children regardless of word type was repetition; however, as children grew older, silent pause, interjection and rejection would appear. The pattern of stuttering both in function and content words changed with age.Conclusion: Farsi stuttering speakers show different patterns of non-fluency in different ages; with more silent prolongation, interjection and revision patterns with older age. According to EXPLAN theory prediction, we expected to see patterns of repetition, interjection and other delaying patterns of stuttering in all age groups. But the presence of different stuttering patterns both in function and content words in different ages, may be due to difference in the structure of function words in Farsi and the higher difficulty in language planning in Farsi than in English.

Objective: The main goal of this research was to examine the cognitive (attribution) models of depression in adolescent students.Method: In this research 388 high school students (222 females and 166 males) from the city of Rey were selected using stratified random sampling. The subjects completed Beck Depression Inventory (BDI), Negative Life Event Questionnaire (NLEQ) and Attribution Style Questionnaire (ASQ). Data were analyzed using exploratory factor analysis, confirmatory factor analysis, path analysis and structural equation modeling by SPSS and LlSREL softwares.Results: Findings showed that among the three attribution models of depression, onset model and sign model showed an acceptable goodness of fit for the explanation of depression whereas vulnerability model did not show a good fit with the data.Conclusion: The findings of this research support the onset and sign models of depression.

Objective: To adapt and normalize the California Critical Thinking Skills Test for university students in the city of Tehran.Method: After the translation and a primary execution of the test, the revised form was completed by 1000 students selected using convenience sampling from the five majors of medicine, humanities, technical and engineering sciences, art and basic sciences. The data were analyzed using mean, standard deviation, Pearson's two-tailed correlation coefficient, Z and t percentage scores for the three skills of evaluation, inference, and analysis; total score based on sexuality for each of the educational groups and the total students were used as well as internal consistency tests (Cronbach's alpha and split-half).Results: The internal consistency of the adapted test was 0.78 using split-half method, and 0.79, 0.75, 0.91, and 0.83 using Cronbach's alpha, for evaluation, analysis, inference and total skills respectively. In addition, the mean scores of critical thought in students of all majors in the universities of Tehran were significantly lower than that of a number of American universities.Conclusion: The validity of the adapted version of the test was acceptable and its norms have been calculated and provided for students in Tehran.