Activation of midbrain structures by associative novelty and the formation of explicit memory in humans

Recent evidence suggests a close functional relationship between memory formation in the hippocampus and dopaminergic neuromodulation originating in the ventral tegmental area and medial substantia nigra of the midbrain. Here we report midbrain activation in two functional MRI studies of visual memory in healthy young adults. In the first study, participants distinguished between familiar and novel configurations of pairs of items which had been studied together by either learning the location or the identity of the items. In the second study, participants studied words by either rating the words' pleasantness or counting syllables. The ventral tegmental area and medial substantia nigra showed increased activation by associative novelty (first study) and subsequent free recall performance (second study). In both studies, this activation accompanied hippocampal activation, but was unaffected by the study task. Thus midbrain regions seem to participate selectively in hippocampus-dependent processes of associative novelty and explicit memory formation, but appear to be unaffected by other task-relevant aspects.     

Irrational beliefs in major depression and generalized anxiety disorders in an Iranian sample: a preliminary study

Previous research on Rational Emotive Theory using western samples has shown that irrational belief systems are associated with emotional disorders such as anxiety and depression. In a replication of this work the present study was conducted to compare the scores of 29 clinically depressed, 31 clinically anxious, and 34 normal controls on the Irrational Beliefs Test in an Iranian sample. Consistent with Ellis's theory, depressed and anxious patients scored higher than the controls on scores for the full scale and all 10 subscales of the Irrational Beliefs Test. Also, the two patient groups differed significantly in their endorsement of 2 out of 10 irrational belief subscales but not in overall score on irrational beliefs. Results were interpreted in light of previous literature.     

Factor structure of the Depression Self-Rating Scale in an Iranian adolescent sample

Previous research showed concurrent validity for the Depression Self-rating Scale for Iranian adolescents, so the present purpose was to evaluate construct validity. The scale was distributed to 2012 school students in Grades 5 to 10. Factor analysis using varimax rotation yielded four factors interpretable as depressed mood, hopelessness, lack of pleasurable activities, and physiological symptoms. These factors accounted for 44% of the variance and provide some support for construct validity of the scale in Iranian adolescents.     

Orientation-selective adaptation to crowded illusory lines

Visual adaptation has been successfully used as a psychophysical tool for studying the functional organisation of visual awareness. It has been shown that orientation-selective adaptation to a grating pattern occurs in crowded conditions. In such conditions, simultaneous presentation of flanking distractors pushes the target stimulus out of conscious perception and severely impairs orientation discrimination in the periphery of the visual field. In the present study, orientation-selective adaptation to illusory lines induced by two line gratings abutting each other with a phase shift was examined in crowded and non-crowded conditions. To rule out the effects of lower level adaptations we used an animation paradigm in which the orientations of the two line gratings were altered repeatedly during adaptation phase without any change in the orientation of the resulting illusory line. Although performance of subjects in reporting the orientation of crowded illusory lines was at chance level, orientation-selective adaptation was preserved for crowded as well as non-crowded adapting targets. Two control experiments demonstrated that adaptation to endpoints of real lines at the location of abutting grating lines had minimal effect on the adaptation to illusory lines; and changes in the configuration of endpoints could not be responsible for better performance when adapting and test stimuli were different. We conclude that a crowding effect occurs after illusory lines have been processed in the visual stream. Since illusory lines seem to be represented at relatively early stages of visual processing (e.g. area V2), adaptation to crowded illusory stimuli suggests that neuronal activation in those early stages is not necessarily correlated with conscious perception.     

Attentional bias for words and faces in social anxiety

Conflicting findings concerning the nature and presence of attentional bias in social anxiety and social phobia have been reported in the literature. This paper reports the findings of two studies comparing people with high and low social anxiety on dot probe tasks using words, faces photographed in front view, and faces photographed in profile as stimuli. In Study 1 those with high social anxiety displayed an attentional bias towards negative faces. The low social anxiety group showed an attentional bias towards positive faces. No significant effects were observed on the dot probe using words as stimuli. Study 2 used pairs of faces presented in profile as though looking at each other. One of the faces displayed either a positive, negative or neutral expression. The second face always had a neutral expression, and in half of the trials it was the subject's own face. The findings of this more ecologically valid procedure replicated those of Study 1. Facilitated attention to dots following emotional faces was specific to threatening facial stimuli. From these studies it appears that the facial dot probe task is a more sensitive index of attentional bias than the word task in a non-clinical sample with social anxiety.     

Atlantis: a time‐value model in e‐commerce

This paper presents a model for resolving two main issues of time in e‐commerce. The first issue is the time value of e‐commerce that represents the value of each moment of the commerce time from the perspective of buyers and sellers. Buyers and sellers can use this model to calculate the time value at each moment of time and accordingly decide whether it is profitable to buy or sell at that moment. The second issue is to allow buyers or sellers to increase their savings or decrease their costs by changing each of the factors governing the time value model of the concerned e‐commerce. We present relevant model specifically for Amazon e‐commerce to present a proof of concept of our proposed models.     

The role of executive functions in bilingual children with reading difficulties

To explore the joint effect of reading difficulties (RD) and bilingualism on executive functions, 190 children of four groups of 9–12 year‐olds (41 bilinguals with RD, 45 monolinguals with RD, 45 bilinguals without RD, and 59 monolinguals without RD) were examined on the Concentration game, Tower of Hanoi, and Stroop as measures of executive functioning tapping into inhibitory/attentional control, working memory and planning ability. The most prominent finding was that in terms of RD, the speed of performances decreased dramatically. This general decrease was more pronounced for bilingual children with RD than for their monolingual counterparts. In conclusion, the findings suggest that while bilinguals gain more from executive functions in normal reading, they lose in terms of RD. Such an outcome confirms that executive functions are essential components of both reading and bilingualism, which depending on whether reading conditions are normal or difficult will produce cognitive advantages or disadvantages. Further, it is argued that dissimilarity between the Farsi and Swedish languages may complicate handling of such a situation.     

Physical Activity in Overweight and Obese Women: Association with Body Mass Index and Demographic Characteristics

The aim of present study was determination of the level of physical activity in overweight and obese women and its association with body mass index and various socio-demographic characteristics. In the present cross-sectional survey, the translated and validated form of International physical activity questionnaire was completed by 300 overweight and obese women from Iran-Tabriz. For each activity level, the MET-time value was calculated. The weight and height of subjects were measured and the BMI was calculated. In addition, subjects were asked to indicate their age, marital and socioeconomic status (including employment, educational status, salaries and material endowments) using a general information questionnaire. The One-way ANOVA, Independent t-test, multiple linear regression analysis were used for statistical analysis. Approximately, 45 % of women were physically inactive. Overweight women were more likely to be physically active as compared to obese, while the lowest physical activity rates were observed in older participants. With increasing age, the time spent in vigorous physical activity declined significantly (p-value?=?0.004). Physically active women had higher Socio-economic status. The average time spent on vigorous physical activities were significantly more in single than married women (p-value?相似文献   

Short-term and Mid-term Effects of Fasting and Downset Meal Pattern on Lipid Profile in Iranian Fasted Women

It is not clear that whether the effects of fasting and downset meal pattern on lipid profile are limited only to Ramadan or do they remain after that month. The cohort study was conducted on 49 women aged 20–45 who worked at Shahid Motahari hospital in Isfahan. They put on groups of 23 consuming downset meal and 26 non-consuming downset meal persons. Serum triglyceride, cholesterol, LDL, and HDL were measured on the 3 days before the beginning, 3 and 30 days after the end of Ramadan. Repeated measure test was used to determine the changes during times and the interaction effects between times and nocturnal eating pattern. This study showed that fasting causes some short-term and mid-term changes in triglyceride and HDL that is mostly attributable to changes in dietary habits during Ramadan, rather than downset meal pattern.