Cortical regions underlying successful encoding of semantically congruent and incongruent associations between common auditory and visual objects.

Recent studies implicate regions in the frontal, temporal and occipital cortices of the brain in audio-visual (AV) integration of familiar objects. It remains unclear, however, which brain regions contribute to the creation of object-related AV memories, and whether activation of these regions is affected by crossmodal congruency. Here we used event-related functional MRI in a subsequent memory paradigm to investigate the neural substrates of successful encoding of semantically congruent and incongruent AV memories. Creation of both types of memories activated a region in the left inferior frontal gyrus (IFG). In addition, successful encoding of semantically related and unrelated AV pairs was correlated with increased activity in regions within the right lateral occipital cortex and bilateral lateral temporal cortex, respectively. These results may highlight a common role of IFG in retrieval of semantic information during encoding and suggest that the occipital and temporal cortices differentially process perceptual versus conceptual associations of AV memories.

Personality traits predict response to novel and familiar stimuli in the hippocampal region.

Current evidence from genetic, neurochemical, and clinical research supports the notion that a combination of high novelty seeking and low harm avoidance traits (NS-ha) is reliably dissociable from the opposite personality profile (i.e., low novelty seeking and high harm avoidance, ns-HA). Little is known, however, about how the differences between these two types of personality are regulated by brain function. Here we used functional magnetic resonance imaging (fMRI) and recruited two groups of individuals, one group with the NS-ha profile and the other group with the ns-HA profile, to examine whether there is a difference between the two groups in their brain response to novel versus familiar word stimuli. Results revealed a differential pattern of response in an area in the hippocampal region, with the NS-ha group showing a greater sensitivity to novel stimuli and the ns-HA group demonstrating a greater response to familiar stimuli. We conclude that the response pattern to novel and familiar stimuli in the hippocampal region has a role in mediating differences between the NS-ha and ns-HA temperamental profiles.

The claustrum/insula region integrates conceptually related sounds and pictures.

The brain is able to create coherent percepts from multisensory input. This phenomenon, known as multisensory integration (MSI), is a ubiquitous feature of everyday life and has been found to be essential for a reliable interaction with the environment. Recent functional neuroimaging studies suggest that several different networks are engaged in various forms of MSI depending on the nature of information being integrated. However, little is known about the neural basis of a fundamental form of MSI in natural conditions; integration of common auditory and visual objects which are conceptually related, such as when we look at a cat and hear a meowing sound. Here we used event-related fMRI to compare the brain response to conceptually related and unrelated pairs of audio-visual stimuli denoting common objects. Our protocol was designed to preclude contamination of the results by cognitive processes additional to those needed for MSI. The results indicate that higher-order temporal and occipital areas respond to coincident sounds and pictures regardless of their semantic relationship; whereas, the right claustrum/insula region is differentially activated in association with multisensory integration of conceptually related common objects. This observation has important implications for understanding how multimodal information about common objects is represented in the brain.

An epidemiological survey of psychiatric disorders in Iran.

BACKGROUND: The nation-wide epidemiological survey of psychiatric disorders in term of lifetime prevalence is not adequately known in Iran. The prevalence of lifetime psychiatric disorders was estimated among the population of aged 18 and over on gender, age group, educational level, occupational status, marital status, and residential area. METHODS: The subjects were 25,180 individuals selected through a clustered random sampling method. The psychiatric disorders were diagnosed on the bases of Diagnostic and Statistical Manual of Mental Disorders-IV criteria. It is the first study in which the structured psychiatric interview administered to a representative sample of the Iranian population age 18 and over by the 250 trained clinical psychologist interviewers. The data was entered through EPI-Info software twice in an attempt to prevent any errors and SPSS-11 statistical software was also used for analyses. The odds ratios and their confidence intervals estimated by using logistic regression. RESULTS AND DISCUSSION: The prevalence of psychiatric disorders was 10.81%. It was more common among females than males (14.34% vs. 7.34%, P < 0.001). The prevalence of anxiety and mood disorders were 8.35% and 4.29% respectively. The prevalence of psychotic disorders was 0.89%; neuro-cognitive disorders, 2.78% and dissociative disorders, 0.77%. Among mood disorders, major depressive disorder (2.98%) and among anxiety disorders, phobic disorder (2.05%) had the higher prevalence. The prevalence of psychiatric disorders among divorced and separated 22.31%; residents of urban areas 11.77%; illiterates 13.80%; householders 15.48%; unemployed 12.33% that were more than other groups. CONCLUSION: The mental health pattern in Iran is similar to the western countries, but it seems that the prevalence of psychiatric disorders in Iran may be lower than these countries. It is estimated that at least about 7 millions of Iranian population suffer from one or more of the psychiatric disorders. It shows the importance of the role of the psychiatric disorders in providing preventive and management programs in Iran.

Common fronto-parietal activity in attention, memory, and consciousness: shared demands on integration?

Fronto-parietal activity has been frequently observed in fMRI and PET studies of attention, working memory, and episodic memory retrieval. Several recent fMRI studies have also reported fronto-parietal activity during conscious visual perception. A major goal of this review was to assess the degree of anatomical overlap among activation patterns associated with these four functions. A second goal was to shed light on the possible cognitive relationship of processes that relate to common brain activity across functions. For all reviewed functions we observed a consistent and overlapping pattern of brain activity. The overlap was most pronounced for the bilateral parietal cortex (BA 7 and BA 40; close to the intraparietal sulcus), and dorsolateral prefrontal cortex (right BA 9 and left BA 6). The common fronto-parietal activity will be discussed in terms of processes related to integration of distributed representations in the brain.

Prevalence of obsessive-compulsive disorder in Iran.

BACKGROUND: Estimates of the annual prevalence for Obsessive Compulsive Disorder (OCD) were consistent across the international sites range, 1.9%-2.5%. The nine population surveys, which used Diagnostic Interview Schedule, estimated a six-month prevalence of OCD ranging from 0.7% to 2.1%. This study performed in order to determine the prevalence of OCD in a population-based study among Iranian adults aged 18 and older and to study the association of them with factors such as sex, marital status, education, type of occupation and residential area. METHODS: A cross-sectional nationwide epidemiological study of the Iranian population aged 18 and older was designed to estimate the prevalence of psychiatric disorders and their association with the above mentioned factors. 25180 individuals were selected and interviewed through a randomized systematic and cluster sampling method from all Iranian households. Schedule for Affective Disorders and Schizophrenia (SADS) and Diagnostic and Statistical Manual of Mental Disorders-IV (DSM-IV) criteria were used in diagnosis of OCD. 250 clinical psychologists interviewed the selected subjects face to face at their homes. RESULTS: The prevalence of OCD in Iran is 1.8% (0.7% and 2.8% in males and females; respectively). 50.3% of the survey sample were men, 49.9% women, 29.1% single, 67.45% married, 0.4% separated or divorced, 2.5% widow/widower and 4% undetermined. All of the above-mentioned factors were examined in the univariate and multivariate logistic regression models. Although the data did not fit the models well, but in univariate models, sex, the category "single" of marital status, age, the categories "business" and "housewife" and residential areas showed significant effect adjusting for the factors, but the models didn't fit the data properly. CONCLUSION: The study suggests that the prevalence of OCD is not rare in the community of Iran and is within the range of other countries. Similar to prior studies in other communities, OCD is more common in females than males.