mohammad ali oghabian

Functional neurological disorders (FND) is one of the most common causes of neuropathy, However, its cause continues to be mysterious. Understanding the underlying mechanisms of FND is crucial for treatment strategies. The study was conducted on brain images(rs-fMRI) taken from two volunteers (FND patient and healthy subject) who had the same characteristics.

We fitted Gaussian Graphical Models to a single subject data using a network approach.

Based on the results of the networks, the number of significant edges was more in the left hemisphere in the patient, but in the healthy person, the number of these non-zero edges was more in the right hemisphere. Both the networks related to the healthy person and the patient had high density. Therefore, it indicated that the regions considered by these 2 people were strongly related to each other. The results showed the existence of more links and positive relationships between the regions, most of which showed a strong relationship. Among these connections, there were also negative connections. The networks of the healthy participant with almost symmetrical structures and the patient with FND showed different characteristics, including asymmetry between the hemispheres.

this study is the first to demonstrate that the brain regions of both FND patient and healthy participant can be conceptualized as networks. The findings of this study add to a growing body of literature that FND patient brain regions can be analyzed using network approaches.

Cue-induced craving is central to addictive disorders. Most cue-reactivity functional magnetic resonance imaging studies are analyzed statically and report averaged signals, disregarding the dynamic nature of craving and task fatigue. Accordingly, this study investigates temporal dynamics of the neural response to drug cues as a functional magnetic resonance imaging study among methamphetamine users. 

A total of 32 early abstinent methamphetamine users underwent functional magnetic resonance imaging while viewing visual methamphetamine cues. A craving > neutral contrast was obtained in regions of interest. To explore the changes over time, the pre-processed signal was divided into three intervals. Contrast estimates were calculated within each interval, and were compared using the analysis of variance followed by the post hoc t-tests. The results were compared with those from a static analysis across all blocks.

A priori expected activations in the prefrontal cortex, insula, and striatum not detected by static analysis were discovered by the dynamic analysis. Post hoc tests revealed distinct temporal activation patterns in several regions. Most patterns showed rapid activation (including both ventral/dorsal striata and most regions in the prefrontal, insular, and cingulate cortices), whereas some had delayed activation (the right anterior insula, left middle frontal gyrus, and left dorsal anterior cingulate cortex).

This study provided preliminary insights into the temporal dynamicity of cue-reactivity, and the potential of a conventional blocked-design task to consider it as a simple dynamic analysis. We highlight regional activations that were only uncovered by dynamic analysis and discuss the interesting and theoretically expected early versus late regional activation patterns. Rapidly activated regions are mostly those involved in the earlier stages of cue reactivity, while regions with later activation participate in cognitive functions relevant later, such as reappraisal, interoception, and executive control.

Intracranial chondroma and chondrosarcoma are very rare tumors that mainly originate from the base of the skull. Advanced neuroimaging studies, including magnetic resonance spectroscopy (MRS), play a pivotal role in both tumor diagnosis and presurgical planning.

We present two cases of intracranial cartilaginous tumors, including a chondroma and a chondrosarcoma, both of which presented with severe headaches. Due to inconclusive conventional MRI and MRS results, they were both primarily diagnosed as intra-axial brain tumors. However, pathological reports later confirmed the diagnosis of a chondroma and a chondrosarcoma.

Based on the present findings, the use of advanced neuroimaging techniques, such as MRS, may improve diagnostic accuracy. We believe that MRS can play a significant role in the surgical planning of similar cases. Also, reporting rare cases worldwide can contribute to the improvement of radiographic diagnosis.

Olfactory system is a vital sensory system in mammals, giving them the ability to connect with their environment. Anosmia, or the complete loss of olfaction ability, which could be caused by injuries, is an interesting topic for inspectors with the aim of diagnosing patients. Sniffing test is currently utilized to examine if an individual is suffering from anosmia; however, functional Magnetic Resonance Imaging (fMRI) provides unique information about the structure and function of the different areas of the human brain, and therefore this noninvasive method could be used as a tool to locate the olfactory-related regions of the brain.

In this study, by recruiting 31 healthy and anosmic individuals, we investigated the neural Blood Oxygenation Level Dependent (BOLD) responses in the olfactory cortices following two odor stimuli, rose and eucalyptus, by using a 3T MR scanner.

Comparing the two groups, we observed a network of brain areas being more active in normal individuals when smelling the odors. In addition, a number of brain areas also showed an activation decline during the odor stimuli, which is hypothesized as a resource allocation deactivation.

This study illustrated alterations in the brain activity between normal individuals and anosmic patients when smelling odors, and could potentially help for a better anosmia diagnosis in the future.

 Preliminary studies have shown that electrical source imaging (ESI) has numerous advantages for the pre-surgical evaluation of epileptic patients. However, the role of ESI for children with non-lesional drug resistance in focal epilepsy has been poorly characterized.

 This study aimed to investigate this issue according to interictal epileptiform discharges (IEDs) and constraints in developing countries.

 The present study used long-term video electroencephalography (EEG) monitoring (LTM) data that were recorded using the standard 19 scalp electrodes (10 - 20 system) and 3 tesla T1 image data. Accordingly, first, IEDs were clustered and then assessed by an epileptologist. Afterward, some operations were conducted that included EEG inverse problem solving with three known methods, namely Brain Electrical Source Analysis (BESA) with the individual head model, cortical classical LORETA analysis recursively analysis with the individual head model, and BESA with the age template head model. Seven children were processed in this project.

 In most cases (n = 5, 71%), the seizure onset zone (SOZ) was the same in the LTM report and the present proposed methodology. Moreover, this study succeeded in localizing the region of the predicted SOZ.

 According to limitations in a developing country, for the configuration of multi-modal studies (e.g., 3T magnetic resonance imaging, LTM, and ESI) with a specific and valuable protocol, this investigation defined a pilot study with a 7 data sample for the first step. These findings, based on the small sample size, suggest that ESI based on combining ensemble methods improves information for children with focal drug-resistant epilepsy. It is hoped that future studies with large sample sizes show the role of ESI in developing countries more than before.

Finding neural correlates underlying deception may have implementations in judicial, security, and financial settings. Telling a successful lie may activate different brain regions associated with risk evaluation, subsequent reward/punishment possibility, decision-making, and theory of mind (ToM). Many other protocols have been developed to study individuals who proceed with deception under instructed laboratory conditions. However, no protocol has practiced lying in a real-life environment. We performed a functional MRI using a 3Tesla machine on 31 healthy individuals to detect the participants who successfully lie in a previously-designed game to earn or lose the monetary reward. The results revealed that lying results in an augmented activity in the right dorsolateral and right dorsomedial prefrontal cortices, the right inferior parietal lobule, bilateral inferior frontal gyri, and right anterior cingulate cortex. The findings would contribute to forensic practices regarding the detection of a deliberate lie. They may also have implications for guilt detection, social cognition, and the societal notions of responsibility.

Addiction is a mental disorder that has many adverse effects on brain health. It alters brain structure and deteriorates brain functionality. Impairment of brain cognition in drug addiction is illustrated in many previous works; however, olfactory perception in addiction and, in particular, its neuronal mechanisms have rarely been studied. 

In this experiment, we recruited 20 heroin addicts and 20 normal controls of the same sex, age, handedness, and socioeconomic status and compared their brain function while perceiving non-craving odors during the functional magnetic resonance imaging (fMRI). We intended to define the default olfactory system performance in addicts compared to healthy people. 

Our study showed an overall larger activation in addicts when processing olfactory stimuli. In particular, and when comparing the two groups, the right anterior cingulate and right superior frontal gyrus had higher activations than normal, whereas the left lingual gyrus and left cerebellum showed stronger activations in the addicts. 

The result of this study can unveil the missing components in addiction brain circuitry. This information is helpful in better understanding the neural mechanisms of addiction and may be advantageous in designing programs for addiction prevention or clinical treatment.

  blood-brain-barrier perfusion characterization impaired in MS as some studies have shown recently but a comparison between perfusion parameters in contrast-enhanced and non-enhanced lesions not have been well documented. Pharmacokinetic quantitative parameters have obtained from dynamic contrast-enhanced in magnetic resonance imaging is a useful way to quantify blood-brain barrier permeability leakage.

 MR examination was performed on 28 patients with Relapsing-remitted Multiple Sclerosis (RRMS) with (Mean±SD age: 34.7±9.28) which had multiple lesions in the brain.3D dynamic T1-weighted spoiled gradient echo was obtained and Perfusion parameters and its map assessed in enhanced and non-enhanced lesions after intravascular injection differences in parameters and map obtained by analyzing ROI in Extended Toft model.

permeability as measured Krtans was a significantly higher value in CE to compare NE lesions. Ktrans and Kep have significant differences in NAWM and CE and NE lesions. Vb was slightly different in NE and CE lesions.

 Permeability measured as Ktrans was the good parameter to show permeability impairment of BBB in CE lesions. Dysregulation in BBB is an acceptable sign to indicate existence inflammation in CE lesions.

 The Patient Health Questionnaire-9 (PHQ-9) is one of the most commonly used measures for screening, diagnosing and monitoring of depression. So far, four studies have examined some of the psychometric properties of Persian version of PHQ-9 in physical and psychiatric patients; however, some aspects of its psychometrics have not yet been adequately evaluated in the student population. Therefore, this study aims to examine more psychometric properties of the Persian version of PHQ-9 in the student population.

 In this descriptive study, 463 students of Guilan University of Medical Sciences in the academic year 2018-19 participated who were selected using a convenience sampling method. The reliability of the Persian PHQ-9 was assessed using internal consistency and test-retest reliability for a 2-week interval. Its construct validity was evaluated by exploratory and confirmatory factor analyses. To evaluate its convergent validity, the second version of the Beck Depression Inventory (BDI-II), the depression subscale of the 21-item Depression Anxiety Depression Inventory (DASS-21), the neuroticism subscale of NEO Five Factor Inventory (NEO-FFI) and the negative affect subscale of the Positive Affect and Negative Affect Scale (PANAS) were used. The openness subscale of NEO-FFI and the positive affect subscale of PANAS were also used to assess its discriminant validity.

 Cronbach’s alpha coefficient of 0.856 and intraclass correlation coefficient of 0.869 indicated high internal consistency and test-retest reliability of the Persian PHQ-9, respectively. Exploratory factor analysis results showed a one-factor structure, accounting for 47.59% of the total variance. Confirmatory factor analysis results showed that all questions were related to one factor. Positive correlation of the Persian PHQ-9 score with BDI-II (r= 0.769), the neuroticism subscale of NEO-FFI (r= 0.508), the depression subscale of DASS-21 (r= 0.647) and the negative affect subscale of PANAS (r= 0.430) indicated an acceptable convergent validity, while its negative correlation with the positive affect subscale PANAS (r= -0.444) indicated its acceptable discriminant validity; however, its score had no significant relationship with the openness subscale of NEO indicates NEO-FFI (r= 0.116).

 The Persian PHQ-9 can be used in clinical and research fields to screen, diagnose, and monitor clinical and/or subclinical depression in the Iranian student population.

The Iranian Brain Imaging Database (IBID) was initiated in 2017, with 5 major goals: provide researchers easy access to a neuroimaging database, provide normative quantitative measures of the brain for clinical research purposes, study the aging profile of the brain, examine the association of brain structure and function, and join the ENIGMA consortium. Many prestigious databases with similar goals are available. However, they were not done on an Iranian population, and the battery of their tests (e.g. cognitive tests) is selected based on their specific questions and needs. 

The IBID will include 300 participants (50% female) in the age range of 20 to 70 years old, with an equal number of participants (#60) in each age decade. It comprises a battery of cognitive, lifestyle, medical, and mental health tests, in addition to several Magnetic Resonance Imaging (MRI) protocols. Each participant completes the assessments on two referral days.

The study currently has a cross-sectional design, but longitudinal assessments are considered for the future phases of the study. Here, details of the methodology and the initial results of assessing the first 152 participants of the study are provided. 

IBID is established to enable research into human brain function, to aid clinicians in disease diagnosis research, and also to unite the Iranian researchers with interests in the brain.

Functional magnetic resonance imaging (fMRI) methods have been used to study sensorimotor processing in the spinal cord. However, these techniques confront unwanted noises to the measured signal from the physiological fluctuations. In the spinal cord imaging, most of the challenges are consequences of cardiac and respiratory movement artifacts that are considered as significant sources of noise, especially in the thoracolumbar region. In this study, we investigated the effect of each source of physiological noise and their contribution to the outcome of the analysis of the blood-oxygen-level-dependent signal in the human thoracolumbar spinal cord.

Fifteen young healthy male volunteers participated in the study, and pain stimuli were delivered on the L5 dermatome between the two malleoli. Respiratory and cardiac signals were recorded during the imaging session, and the generated respiration and cardiac regressors were included in the general linear model for quantification of the effect of each of them on the task-analysis results.  The sum of active voxels of the clusters was calculated in the spinal cord in three correction states (respiration correction only, cardiac correction only, and respiration and cardiac noise corrections) and analyzed with analysis of variance statistical test and receiver operating characteristic curve.

The results illustrated that cardiac noise correction had an effective role in increasing the active voxels (Mean±SD= 23.46±9.46) compared to other noise correction methods. Cardiac effects were higher than other physiological noise sources

In summary, our results indicate great respiration effects on the lumbar and thoracolumbar spinal cord fMRI, and its contribution to the heartbeat effect can be a significant variable in the individual fMRI data analysis. Displacement of the spinal cord and the effects of this noise in the thoracolumbar and lumbar spinal cord fMRI results are significant and cannot be ignored.

Studying different pathological aspects of lesions in multiple sclerosis (MS) patients could be useful to modify the diagnosis and treatment of this neurological disorder. Magnetic resonance imaging (MRI) modalities have the potential to investigate variations in brain tissue because of inflammatory and neurodegenerative processes in various types of MS-related lesions.

This study was done to investigate the quantitative changes in MRI-based parameters, like perfusion and magnetization transfer ratio (MTR) of different types of brain lesions, to demonstrate the ability of MRI to detect structural and pathological differences in MS lesions.

Quantitative MRI modalities were performed on 18 patients with five different kinds of lesions (T1 holes, acute and chronic white matter (WM), and acute and chronic gray matter (GM) lesions) using a 3 T MRI scanner. The following protocols were used to characterize the pathology of lesions: (I) fluid-attenuated inversion recovery (FLAIR); (II) pre- and post-contrast T1-weighted; (III) dynamic contrast-enhanced (DCE); and (IV) MTR imaging. Quantitative comparison of Ktrans, cerebral blood volume (CBV), cerebral blood flow (CBF), and MTR was done to find the best parameter to distinguish different lesions. Finally, a multivariate classifier was applied to introduce the best parameter to indicate differences in lesions.

Five lesions were characterized by perfusion and MTR parameters. The pathological changes were measured, including: (I) the highest value of parameters in both acute WM and GM lesions; (II) the lowest value of four parameters in both chronic WM and GM lesions; (III) MTR had the highest rank among parameters using the classifier.

The degree of pathological alterations due to inflammatory and neurodegenerative processes in MS-related lesions was indicated through the used parameters in different kinds of lesions. Inflammation was the dominant process in acute lesions, while neurodegeneration and tissue loss were observed mostly in chronic lesions. Both inflammation and neurodegeneration were detected in T1 holes. Perfusion parameters and MTR were reasonable parameters to describe differences in brain lesions. Thus, it could be confirmed that magnetization transfer imaging (MTI) and DCE-MRI are high-sensitivity methods to detect microstructural changes in the brain and subtle changes in the blood-brain-barrier. Classification of the parameters indicated that MTR was the best biomarker than others to show variations in lesions pathology.

Cancer detection in early stage using a powerful and noninvasive tool is of high global interest. In this experiment, a small-molecular-weight glucose based derivative of Gd3+-1-(4-isothiocyanatobenzyl) diethylene tri amine penta acetic acid (Gd3+-p-SCN-Bn‐DTPA‐DG) as a novel potential MR imaging contrast agents was synthesized. Gd3+-p-SCN-Bn‐DTPA‐DG was synthesized with reacting of Glucosamine and 1-(4-isothiocyanatobenzyl) diethylene tri amine penta acetic acid then loaded by gadolinium to make novel agent of functional MR imaging. The relaxivity, T1, T2 relaxation times, and cell toxicity of this contrast agent were studied. The results demonstrated that the sugar moieties linked to Gd3+-p-SCN-Bn‐DTPA efficiently increase its cellular uptake. The Gd3+-p-SCN-Bn‐DTPA‐DG significantly decreased MCF-7 tumor cell numbers without any significant toxicity on normal human kidney cells. Finally, it displayed an intense signal on T1 weighted with respect to the unlabeled cells. Based on the findings from the present research Gd3+-p-SCN-Bn‐DTPA‐DG be a potential breast molecular imaging. However, further investigations by anticancer studies are in the pipeline.

Determining the activated brain areas due to different activities is one of the most common targets in functional magnetic resonance imaging (fMRI) data analysis, which could be carried out by hemodynamic response function (HRF) evaluation. The HR functions reflect changes of cerebral blood flow (CBF) in response to neural activity.

In this study, five models of HRF estimation were evaluated based on a simulated dataset. Models with higher accuracy were used to determine HRF parameters of the block-design fMRI data.

The fMRI data were acquired in a 3 Tesla scanner. For block-design fMR imaging, CO2 gas was administered using a facemask under physiological monitoring. Three patients with brain tumors were scanned. The fMRI data analysis was performed using the SPM 12 MATLAB toolbox. Akaike’s information criterion (AIC), Schwarz’ Bayesian (SBC), and mean square error (MSE) criteria were used to select the best HRF estimation model.

In simulation studies, the estimated HRFs by the canonical HRF plus its temporal derivative (TD), finite impulse response (FIR), and inverse logistic (IL) models were almost equal to the standard HRF. Mean square error, AIC, and SBC indices were ignorable for TD, FIR, and IL models (MSE/AIC/SBC magnitudes for TD, FIR, and IL models were 0.052/-1235.1/-1223.9, 0.055/-1206.4/-1194.9, and 0.068/-1091.5/-1049.2, respectively), which indicates that these models could accurately estimate HRF in block design fMRI studies.

The HRF models could non-invasively evaluate the change of MR signal intensity under cerebrovascular reactivity (CVR) conditions and they might be helpful to investigate changes in human cerebral blood flow.

Graph theoretical analysis of functional Magnetic Resonance Imaging (fMRI) data has provided new measures of mapping human brain in vivo. Of all methods to measure the functional connectivity between regions, Linear Correlation (LC) calculation of activity time series of the brain regions as a linear measure is considered the most ubiquitous one. The strength of the dependence obligatory for graph construction and analysis is consistently underestimated by LC, because not all the bivariate distributions, but only the marginals are Gaussian. In a number of studies, Mutual Information (MI) has been employed, as a similarity measure between each two time series of the brain regions, a pure nonlinear measure. Owing to the complex fractal organization of the brain indicating self-similarity, more information on the brain can be revealed by fMRI Fractal Dimension (FD) analysis.
In the present paper, Box-Counting Fractal Dimension (BCFD) is introduced for graph theoretical analysis of fMRI data in 17 methamphetamine drug users and 18 normal controls. Then, BCFD performance was evaluated compared to those of LC and MI methods. Moreover, the global topological graph properties of the brain networks inclusive of global efficiency, clustering coefficient and characteristic path length in addict subjects were investigated too.
Compared to normal subjects by using statistical tests (P Based on the results, analyzing the graph topological properties (representing the brain networks) based on BCFD is a more reliable method than LC and MI.

In recent years, a few studies have addressed the effect of chronic heroin use on brain structure with respect to volume and shape; however, the literature in this field is sparse and further studies are necessary to generate robust replications.
In this study, we intended to assess gray matter density (GMD) differences between successfully abstinent heroin dependents and healthy subjects. Indirect evidences for the causal role of drug use in the GMD differences are also targeted here by testing the hypothesis on the correlation between GMD differences and duration of drug use.
Patients and Using structural magnetic resonance imaging (MRI) and voxel-based morphology (VBM) technique, changes in gray matter volume and density were evaluated in 18 abstinent heroin dependents and 20 age-, education- and gender-matched healthy subjects. Heroin dependents were all male, and at least 3 months successfully abstinent (mean abstinence duration = 9.2 ± 5.2 months).
Decreased GMD in the right anterior cingulate cortex and bilateral putamen were found in abstinent heroin dependents in comparison to controls, corrected for multiple comparisons (P Specific structural changes were noticeable in prefrontal and striatal areas in the heroin dependents even after a period of successful abstinence. Our results on the interaction between duration of drug use and some of these structural changes provides preliminary ideas for reciprocal cause and effect roles for brain structural changes and heroin abuse. These findings might also imply that brain structures are unable to return to normal state and cannot recover spontaneously even after months of abstinence. This evidence reminds us of the importance of neurorehabilitation interventions after termination of drug use.

Various treatment methods for drug abusers will result in different success rates. This is partly due to different neural assumptions and partly due to various rate of relapse in abusers because of different circumstances. Investigating the brain activation networks of treated subjects can reveal the hidden mechanisms of the therapeutic methods.
We studied three groups of subjects: heroin abusers treated with abstinent based therapy (ABT) method, heroin abusers treated with Methadone Maintenance Therapy (MMT) method, and a control group. They were all scanned with functional magnetic resonance imaging (fMRI), using a 6-block task, where each block consisted of the rest-craving-rest-neutral sequence. Using the dynamic causal modeling (DCM) algorithm, brain effective connectivity network (caused by the drug craving stimulation) was quantified for all groups. In this regard, 4 brain areas were selected for this analysis based on previous findings: ventromedial prefrontal cortex (VMPFC), dorsolateral prefrontal cortex (DLPFC), amygdala, and ventral striatum.
Our results indicated that the control subjects did not show significant brain activations after craving stimulations, but the two other groups showed significant brain activations in all 4 regions. In addition, VMPFC showed higher activations in the ABT group compared to the MMT group. The effective connectivity network suggested that the control subjects did not have any direct input from drug-related cue indices, while the other two groups showed reactions to these cues. Also, VMPFC displayed an important role in ABT group. In encountering the craving pictures, MMT subjects manifest a very simple mechanism compared to other groups.
This study revealed an activation network similar to the emotional and inhibitory control networks observed in drug abusers in previous works. The results of DCM analysis also support the regulatory role of frontal regions on bottom regions. Furthermore, this study demonstrates the different effective connectivity patterns after drug abuse treatment and in this way helps the experts in the field.

Functional magnetic resonance imaging (fMRI) is a non-invasive and convenient method of mapping brain activity associated with the human sensory systems. Among these systems there is a lack of data from olfactory studies, which could be attributed to technical difficulties in odor delivery during scanning. The current study took advantage of an olfactometer to evaluate brain activity during the odor-smelling process.
This study aimed to investigate the brain regions of the human olfactory system via fMRI brain imaging. A speculative survey was used to highlight the differences between studies conducted in healthy populations using olfactory tasks, as well as conducting literature survey in terms of the technical principles applying through these tasks in fMRI studies.
Subjects and A functional map of the olfactory system that used a block design, alternating between odor and non-odor phases, was examined in 15 healthy volunteers. The general linear model was used to identify statistically significant voxels that showed activation during the activation blocks.
Primary and secondary olfactory regions, including the piriformis, insula, amygdala, parahippocampal gyrus, caudate nucleus, inferior frontal gyrus, middle frontal gyrus, superior temporal gyrus, and cerebellum, demonstrated significant activation in response to odor stimulation.
Activation of the aforementioned brain areas, and the pattern of activation, is largely in accordance with previous published olfactory studies carried out in healthy individuals.

Neural correlates of visual confrontation naming (VCN) have received considerable attention in previous literature. Recently, there have been a few studies that have reported the activation of the hippocampus during VCN tasks. Whether or not the hippocampus is directly involved in picture naming has clinical importance for patients with refractory mesial temporal lobe epilepsy (MTLE) who should undergo anterior temporal lobe resection (ATLR).
In this study, we investigated the neural network of VCN and the role of the hippocampus in Persian-speaking individuals by functional magnetic resonance imaging (fMRI) VCN paradigm.
Subjects and Twenty right-handed, healthy, Persian-speaking adults underwent fMRI while performing VCN task. Pictures were selected from a Snodgrass and Vanderwart dataset that was normed for Persian speakers. VCN performance was assessed and entered as a covariate in whole-brain analysis. Region of interest (ROI)-based analysis was also used to obtain more accurate results.
Activation in the left hippocampus was significantly correlated with VCN performance. Participants with higher scores showed greater fMRI activation in their left hippocampus. Activation in left occipitotemporal regions, such as the left occipital fusiform gyrus, left temporal occipital fusiform gyrus, left temporal pole, left middle temporal gyrus, and left superior temporal gyrus also showed significant correlation with VCN performance. The main effects of VCN were also found in frontal and occipital regions, such as the left inferior frontal gyrus, right inferior frontal gyrus, right orbital frontal gyrus, right lateral occipital gyrus, right occipital fusiform gyrus, and right occipital pole. Activation in the inferior frontal gyrus was significantly left lateralized among all of the subjects.
These findings suggest that good naming ability depends on fMRI activation in the speech-dominant hippocampus. We also found that a left-dominant network of occipitotemporal regions plays a dominant role in VCN performance in healthy Persian-speaking individuals.

Quantitative susceptibility mapping (QSM) is a new contrast mechanism in magnetic resonance imaging (MRI). The images produced by the QSM enable researchers and clinicians to easily localize specific structures of the brain, such as deep brain nuclei. These nuclei are targets in many clinical applications and therefore their easy localization is a must. In this study, we aimed to implement two QSM estimation algorithms, threshold-based k-space division (TKD) and morphology enabled dipole inversion (MEDI) in presurgical planning.
In this study, susceptibility weighted imaging (SWI) was performed on six patients referred to our center for presurgical planning purposes. The susceptibility values, as well as the contrast-to-noise ratio of few brain regions were estimated. To identify the algorithm, which was best applicable to clinics, a comparison of the two methods was performed.
QSM images were produced; however, the results did not show any significant differences between the susceptibility values of the two methods. The contrast-to-noise ratio for the susceptibility values of the subthalamic nucleus and substantia nigra brain regions were significantly superior using the MEDI approach over TKD, suggesting improved localization of brain regions using the former method.
This study suggests that to identify specific brain regions, such as deep brain nuclei, a QSM contrast would be more beneficial than the conventional MRI contrasts. This study compared MEDI and TKD methods for quantification of brain susceptibility maps, and results showed that the MEDI method resulted in higher-quality images.

Effective connectivity is an active type of association between brain regions, and its resulting network is observed to change with time. The change of links’ strength in effective connectivity networks has been studied before using Granger Causality method but as far as we know, the change in the structure of the network has not yet been tested. We used a simulated time-variable data including three regions and one input to validate our method. In addition we used a real fMRI data in order to evaluate the time-variability of brain effective connectivity between four brain regions using Dynamic Causal Modeling. For this data the model space contained 38 models, all including the four regions of ventromedial prefrontal cortex, dorsolateral prefrontal cortex, amygdala, and ventral striatum. In both data a proper moving window algorithm was used to find the changes during time. The results of simulated data showed good compliance to the input pattern change during time. The results of real data initially showed time-dependent changes in the strength of some of the connections between brain regions. The most valid changes happened in the input and non-linear modulatory links. The input links’ strength increased and the nonlinear links’ strength decreased exponentially during time. These results show that the pattern of effective connectivity network changes during time and so reporting a single network for the whole data acquisition period is not meaningful. In this study, we have used a method to find the time-dependent pattern change during an fMRI task. We have shown the links’ strength change during time and accordingly the structure of the network changes.

Iron oxide nanoparticles have found prevalent applications in various fields including drug delivery, cell separation and as contrast agents. Super paramagnetic iron oxide (SPIO) nanoparticles allow researchers and clinicians to enhance the tissue contrast of an area of interest by increasing the relaxation rate of water. In this study, we evaluate the dependency of hydrodynamic size of iron oxide nanoparticles coated with Polyethylene glycol (PEG) on their relativities with 3 Tesla clinical MRI.
We used three groups of nanoparticles with nominal sizes 20, 50 and 100 nm with a core size of 8.86 nm, 8.69 nm and 10.4 nm that they were covered with PEG 300 and 600 Da. A clinical magnetic resonance scanner determines the T1 and T2 relaxation times for various concentrations of PEG-coated nanoparticles.
The size measurement by photon correlation spectroscopy showed the hydrodynamic sizes of MNPs with nominal 20, 50 and 100 nm with 70, 82 and 116 nm for particles with PEG 600 coating and 74, 93 and 100 nm for particles with PEG 300 coating, respectively. We foud that the relaxivity decreased with increasing overall particle size (via coating thickness). Magnetic resonance imaging showed that by increasing the size of the nanoparticles, r2/r1 increases linearly.
According to the data obtained from this study it can be concluded that increments in coating thickness have more influence on relaxivities compared to the changes in core size of magnetic nanoparticles.

Drug craving could be described as a motivational state which drives drug dependents towards drug seeking and use. Different types of self-reports such as craving feeling, desire and intention, wanting and need, imagery of use, and negative affect have been attributed to this motivational state. By using subjective self-reports for different correlates of drug craving along with functional neuroimaging with cue exposure paradigm, we investigated the brain regions that could correspond to different dimensions of subjective reports for heroin craving. A total of 25 crystalline-heroin smokers underwent functional magnetic resonance imaging (fMRI), while viewing heroin-related and neutral cues presented in a block-design task. During trial intervals, subjects verbally reported their subjective feeling of cue induced craving (CIC). After fMRI procedure, participants reported the intensity of their “need for drug use” and “drug use imagination” on a 0-100 visual analog scale (VAS). Afterwards, they completed positive and negative affect scale (PANAS) and desire for drug questionnaire (DDQ) with 3 components of “desire and intention to drug use,” “negative reinforcement,” and “loss of control.” The study showed significant correlation between “subjective feeling of craving” and activation of the left and right anterior cingulate cortex, as well as right medial frontal gyrus. Furthermore, the “desire and intention to drug use” was correlated with activation of the left precentral gyrus, left superior frontal gyrus, and left middle frontal gyrus. Subjects also exhibited significant correlation between the “need for drug use” and activation of the right inferior temporal gyrus, right middle temporal gyrus, and right parahippocampal gyrus. Correlation between subjective report of “heroin use imagination” and activation of the cerebellar vermis was also observed. Another significant correlation was between the “negative affect” and activation of the left precuneus, right putamen, and right middle temporal gyrus. This preliminary study proposes different neural correlates for various dimensions of subjective craving self-reports. It could reflect multidimensionality of cognitive functions corresponding with drug craving. These cognitive functions could represent their motivational and affective outcomes in a single item “subjective craving feeling” or in self-reports with multiple dissociable items, such as intention, need, imagination, or negative feeling. The new psychological models of drug craving for covering various dimensions of subjective craving self-reports based on their neurocognitive correspondence could potentially modify craving assessments in addiction medicine.

Multifunctional core-shell magnetic nanocomposite particles with tunable characteristics have been paid much attention for biomedical applications in recent years. A rational design and suitable preparation method must be employed to be able to exploit attractive properties of magnetic nanocomposite particles. Herein, we report on a simple approach for the synthesis of magnetic mesoporous silica nanocomposite particles (MMSPs), consisted of a Fe3O4 cluster core, a nonporous silica shell and a second shell of the mesoporous silica of suitable sizes for biomedical applications and evaluate their cytotoxicity effects on human cancer prostate cell lines. Clusters of magnetite (Fe3O4) nanoparticles were coated by a layer of nonporous silica using Stöber method. The coating step was completed by an outer layer of mesoporous silica via template-removing method. Structural properties of MMSPs were investigated by FTIR, HR-S(T)EM, BET, XRD techniques and magnetic properties of MMSPs by VSM instrument. MTT and LDH assays were employed to study the cytotoxicity of MMSPs. Obtained results revealed that decreasing the precursor concentration and the reaction time at the nonporous silica shell formation step decreases the thickness of the nonporous silica shell and consequently leads to the formation of smaller MMSPs. The as-prepared MMSPs have a desirable average size of 180±10 nm, an average pore size of 3.01 nm, a high surface area of 390.4 m2.g-1 and a large pore volume of 0.294 cm3.g-1. In addition, the MMSPs exhibited a superparamagnetic behavior and a high magnetization saturation value of 21±0.5 emu/g. Furthermore, the viability tests of DU-145 cell lines exposed to various concentrations of these particles demonstrated negligible cytotoxicity effects of the as-prepared particles. These results demonstrate interesting properties of MMSPs prepared in this study for biomedical applications.

The perception of music relies on many culture-specific factors; nevertheless this is processed by physiological and functional attributes of the brain system. The aim of this study is to evaluate the functional activity of brain during the perception of rhythm and melody in Persian classical music using fMRI. The test consists of two groups of Persian Modal music scales, frequently called Dastgāh. Mahour and Homayoun, in two parts of non-rhythmic and rhythmic pieces presented on 19 right-handed non-musicians. The results of this study revealed the brain activities for each of rhythmic and non-rhythmic versions of Mahour and Homayoun Dastgah. For non-rhythmic Mahour, the activation was found in right lingual gyrus, right precuneous cortex, left Inferior frontal gyrus, and left temporal lobe; whereas for rhythmic Mahour, the areas contain left supplementary motor cortex, left superior frontal gyrus, right and left precentral and postcentral gyrus, left supramarginal gyrus, and right temporal pole.The activated regions for non-rhythmic Homayoun include right and left subcallosal cortex, left medial frontal cortex, left anterior cingulate gyrus, and left frontal pole. In contrast, for rhythmic Homayoun, alternative areas including left precentral gyrus, left precuneous cortex, left anterior supramarginal, and left postcentral gyrus were revealed. rhythmic pieces were shown to activate the areas mostly involved in movement while non-rhythmic pieces related to emotional and memory regions. Although, these results are not consistent totally with the previous findings on western music, they are similar to the outcomes performed on eastern cultural subjects.