Ripples in macaque V1 and V4 are modulated by top-down visual attention.

Sharp-wave ripples (SWRs) are highly synchronous neuronal activity events. They have been predominantly observed in the hippocampus during offline states such as pause in exploration, slow-wave sleep, and quiescent wakefulness. SWRs have been linked to memory consolidation, spatial navigation, and spatial decision-making. Recently, SWRs have been reported during visual search, a form of remote spatial exploration, in macaque hippocampus. However, the association between SWRs and multiple forms of awake conscious and goal-directed behavior is unknown. We report that ripple activity occurs in macaque visual areas V1 and V4 during focused spatial attention. The occurrence of ripples is modulated by stimulus characteristics, increased by attention toward the receptive field, and by the size of the attentional focus. During attention cued to the receptive field, the monkey's reaction time in detecting behaviorally relevant events was reduced by ripples. These results show that ripple activity is not limited to hippocampal activity during offline states, rather they occur in the neocortex during active attentive states and vigilance behaviors.

Iranian emotional face database: Acquisition and validation of a stimulus set of basic facial expressions.

Facial expressions play an essential role in social interactions. Databases of face images have furnished theories of emotion perception, as well as having applications in other disciplines such as facial recognition technology. However, the faces of many ethnicities remain largely underrepresented in the existing face databases, which can impact the generalizability of the theories and technologies developed based on them. Here, we present the first survey-validated database of Iranian faces. It consists of 248 images from 40 Iranian individuals portraying six emotional expressions-anger, sadness, fear, disgust, happiness, and surprise-as well as the neutral state. The photos were taken in a studio setting, following the common scenarios of emotion induction, and controlling for conditions of lighting, camera setup, and the model's head posture. An evaluation survey confirmed high agreement between the models' intended expressions and the raters' perception of them. The database is freely available online for academic research purposes.

Direct and Indirect Measures of Attention Indicating a Bias Toward Cues in Methamphetamine Users.

Introduction: This study aims to investigate the attentional bias toward drug-related stimuli along with subjective craving after encountering such stimuli in methamphetamine users. Studies of cue reactivity have confirmed a bias in attention and gaze toward drug-related stimuli for most substances; however, methamphetamine drugs are less studied through a direct measure, such as eye tracking. Methods: A total of 30 male subjects in the case group (methamphetamine users) and 36 subjects in the control group (no prior drug use) participated in this study. The participant's eye movement data were collected while they were viewing pairs of drug-related and non-drug images in a dot-probe paradigm. Craving was assessed via a self-report questionnaire on a scale of 0 to 10 before and after the psychophysical task. Results: The analysis of eye-movement data showed a meaningful gaze bias toward cue images (drug-related) in the case group. Additionally, the gaze duration on cue images was significantly higher in the case group, in contrast to the control group. The same effect was observed in analyzing the dot-probe task; that is, the mean reaction time to a probe that replaced a cue image was significantly lower. The mean of the first-fixation measure in the control group was not significantly higher than chance; however, the percentage of the first-fixation on cue images in the drug users was meaningfully biased. Reported craving was significantly greater after performing the task compared to before. Conclusion: Our results indicated an attentional bias toward drug-related cues in methamphetamine users as well as subjective craving after encountering such cues. Highlights: The gaze duration on cue images was significantly higher in methamphetamine users.The mean reaction time to a probe that replaced a cue image was significantly lower in methamphetamine users compared to the control group.The mean of the first-fixation measure in the case group was significantly better than chance.Craving was reported to be significantly greater after performing the task. Plain Language Summary: Substance users tend to focus on the stimuli associated with substances. This is known as attention bias. Attention bias leads to increased craving. Attention bias for various substances has been previously reported; however, methamphetamine attention bias has not been evaluated so far. In this study, we measured the attention bias toward stimuli related to methamphetamine in methamphetamine users and control subjects with direct (eye tracking) and indirect (dot probe paradigm) methods. In addition, we measured the number of cravings in the case group. Our results confirmed the bias in attention toward methamphetamine-related stimuli in the case group compared to the control group.

The effect of the mobile "blood pressure management application" on hypertension self-management enhancement: a randomized controlled trial.

BACKGROUND: Self-management of hypertension is of great significance given its increasing incidence and its associated disabilities. In view of the increased use of mobile health in medicine, the present study evaluated the effect of a self-management application on patient adherence to hypertension treatment. METHODS: This clinical trial was performed on 120 hypertensive patients who were provided with a mobile intervention for 8 weeks and followed up until the 24th week. Data on the primary outcome (adherence to treatment) and secondary outcomes (adherence to the DASH diet, regular monitoring of blood pressure, and physical activity) were collected using a questionnaire and a mobile application, respectively. The inter-group change difference over time was analyzed using repeated measures ANOVA (general linear model). RESULTS: The treatment adherence score increased by an average of 5.9 (95% CI 5.0-6.7) in the intervention group compared to the control group. The scores of "adherence to the low-fat and low-salt diet plans" were 1.7 (95% CI 1.3-2.1) and 1.5 (95% CI 1.2-1.9), respectively. Moreover, moderate physical activity increased to 100.0 min (95% CI 61.7-138.3) per week in the intervention group. CONCLUSION: The treatment and control of blood pressure require a multifaceted approach given its complexity and multifactorial nature. Considering the widespread use of smartphones, mHealth interventions can be effective in self-management and better patient adherence to treatments. Our results showed that this application can be used as a successful tool for hypertension self-management in patients attending public hospitals in developing countries. TRIAL REGISTRATION: Iran Randomized Clinical Trial Center IRCT2015111712211N2 . Registered on 1 January 2016.

Crosstalk between Sleep Disturbance and Opioid Use Disorder: A Narrative Review.

Recent studies have revealed a growing number of patients affected by opioid use disorders (OUDs). Comorbid disorders are suspected to increase the risk of opioid-related adverse effects or treatment failure. The correlation of opioid use with sleep disturbances has been reported in many different studies and suggested to be linked to the brain regions involved in reward processing. This narrative review was intended to discuss the most recent developments in our understanding of the intricate interaction between sleep disturbance and OUD. In addition, in this study, the effects of sleep problems on the occurrence of unpleasant consequences in addiction management, such as craving and relapse in OCD patients, were highlighted. It has been shown that drug use may trigger the induction of sleep disturbances, and those suffering from difficulties in sleeping are prone to relapse to drug use, including opioids. Moreover, pharmaceutical sleep aids are likely to interfere with opiate use.

Phase-synchrony evaluation of EEG signals for Multiple Sclerosis diagnosis based on bivariate empirical mode decomposition during a visual task.

BACKGROUND AND OBJECTIVE: Despite the widespread prevalence of Multiple Sclerosis (MS), the study of brain interactions is still poorly understood. Moreover, there has always been a great need to automate the MS diagnosis procedure to eliminate the evaluation errors thereby improving its consistency and reliability. To address these issues, in this work, we proposed a robust pattern recognition algorithm as a computer-aided diagnosis system. This method is based on calculating the pairwise phase-synchrony of EEG recordings during a visual task. Initially, the bivariate empirical mode decomposition (BEMD) was applied to extract the intrinsic mode functions (IMFs). The phases of these IMFs were then obtained using the Hilbert transform to be utilized in the mean phase coherence (MPC), a measure for phase-synchrony calculation. After the construction of the feature space using MPC values, the ReliefF algorithm was applied for dimension reduction. Finally, the best distinguishing features were input to a k-nearest neighbor (KNN) classifier. The results revealed a higher level of network synchronization in the posterior regions of the brain and desynchronization in the anterior regions among the MS group as compared with the normal subjects. In the validation phase, the leave-one-subject-out cross-validation (LOOCV) method was used to assess the validity of the proposed algorithm. We achieved an accuracy, sensitivity, and specificity of 93.09%, 91.07%, and 95.24% for red-green, 90.44%, 88.39%, and 92.62% for luminance, and 87.44%, 87.05%, and 87.86% for blue-yellow tasks, respectively. The experimental results demonstrated the reliability of the presented method to be generalized in the field of automated MS diagnosis systems.

The Effect of Continuous Theta-Burst Transcranial Magnetic Stimulation Combined with Prism Adaptation on the Neglect Recovery in Stroke Patients.

OBJECTIVES: This study was designed to investigate the effect of prism adaptation (PA) combined with continuous theta-burst transcranial magnetic stimulation (cTBS) on the neglect recovery of stroke patients with unilateral neglect. METHODS: A total of 14 stroke patients with unilateral neglect were randomly assigned to 2 groups including an intervention group undergone PA combined with cTBS over the left intact parietal cortex and a control group. PA combined with sham cTBS was perfomed for 2 weeks in 10 daily sessions. Before and after the intervention, patients were evaluated for visuospatial neglect measured using the Star Cancellation Test (SCT), Line Bisection Task (LBT), Figure Copying Test, and Clock Drawing Task. Neurological function was evaluated using the Modified Rankin Scale (MRS). RESULTS: Both groups (PA alone and PA+ cTBS) showed improvement in their neglected symptoms (measured by SCT, LBT, Figure Copying Test, and Clock Drawing Task), and in their disability in the neurological function (measured by MRS) (P< .05). CONCLUSIONS: The results of the present study showed that, transcranial magnetic stimulation did not increase the effect of PA on neglect symptoms in stroke patients.

Longitudinal Effects of Bumetanide on Neuro-Cognitive Functioning in Drug-Resistant Epilepsy.

Antiepileptic drugs (AEDs) have repeatedly shown inconsistent and almost contradictory effects on the neurocognitive system, from substantial impairments in processing speed to the noticeable improvement in working memory and executive functioning. Previous studies have provided a novel insight into the cognitive improvement by bumetanide as a potential antiepileptic drug. Through the current investigation, we evaluated the longitudinal effects of bumetanide, an NKCC1 co-transporter antagonist, on the brain microstructural organization as a probable underlying component for cognitive performance. Microstructure assessment was completed using SPM for the whole brain assay and Freesurfer/TRACULA for the automatic probabilistic tractography analysis. Primary cognitive operations including selective attention and processing speed, working memory capacity and spatial memory were evaluated in 12 patients with a confirmed diagnosis of refractory epilepsy. Participants treated with bumetanide (2 mg/ day) in two divided doses as an adjuvant therapy to their regular AEDs for 6 months, which followed by the re-assessment of their cognitive functions and microstructural organizations. Seizure frequency reduced in eight patients which accompanied by white matter reconstruction; fractional anisotropy (FA) increased in the cingulum-cingulate gyrus (CCG), anterior thalamic radiation (ATR), and temporal part of the superior longitudinal fasciculus (SLFt) in correlation with the clinical response. The voxel-based analysis in responder patients revealed increased FA in the left hippocampus, right cerebellum, and right medial temporal lobe, while mean diffusivity (MD) values reduced in the right occipital lobe and cerebellum. Microstructural changes in SLFt and ATR accompanied by a reduction in the error rate in the spatial memory test. These primary results have provided preliminary evidence for the effect of bumetanide on cognitive functioning through microstructural changes in patients with drug-resistant epilepsy.

Normal Electrical Activity of the Brain in Obsessive-Compulsive Patients After Anodal Stimulation of the Left Dorsolateral Prefrontal Cortex.

INTRODUCTION: Transcranial Direct Current Stimulation (tDCS) has been used as a non-invasive method to increase the plasticity of brain. Growing evidence has shown several brain disorders such as depression, anxiety disorders, and chronic pain syndrome are improved following tDCS. In patients with Obsessive-Compulsive Disorder (OCD), increased brain rhythm activity particularly in the frontal lobe has been reported in several studies using Eectroencephalogram (EEG). To our knowledge, no research has been done on the effects of electrical stimulation on brain signals of patients with OCD. We measured the electrical activity of the brain using EEG in patients with OCD before and after tDCS and compared it to normal participants. METHODS: Eight patients with OCD (3 males) and 8 matched healthy controls were recruited. A 64-channel EEG was used to record a 5-min resting state before and after application of tDCS in both groups. The intervention of tDCS was applied for 15 minutes with 2 mA amplitude where anode was placed on the left Dorsolateral Prefrontal Cortex (DLPFC) and cathode on the right DLPFC. RESULTS: In line with previous studies, the results showed that the power of Delta frequency band in OCD patients are significantly higher than the normal group. Following anodal tDCS, hyperactivity in Delta and Theta bands declined in most channels, particularly in DLPFC (F3, F4) and became similar to normal signals pattern. The reduction in Delta band was significantly more than the other bands. CONCLUSION: Anodal tDCS over the left DLPFC significantly decreased the power of frequency bands of Delta and Theta in Patients with OCD. The pattern of EEG activity after tDCS became particularly similar to normal, so tDCS may have potential clinical application in these patients.

Effect of Mild Cognitive Impairment and Alzheimer Disease on Auditory Steady-State Responses.

INTRODUCTION: Mild Cognitive Impairment (MCI), a disorder of the elderly people, is difficult to diagnose and often progresses to Alzheimer Disease (AD). Temporal region is one of the initial areas, which gets impaired in the early stage of AD. Therefore, auditory cortical evoked potential could be a valuable neuromarker for detecting MCI and AD. METHODS: In this study, the thresholds of Auditory Steady-State Response (ASSR) to 40 Hz and 80 Hz were compared between Alzheimer Disease (AD), MCI, and control groups. A total of 42 patients (12 with AD, 15 with MCI, and 15 elderly normal controls) were tested for ASSR. Hearing thresholds at 500, 1000, and 2000 Hz in both ears with modulation rates of 40 and 80 Hz were obtained. RESULTS: Significant differences in normal subjects were observed in estimated ASSR thresholds with 2 modulation rates in 3 frequencies in both ears. However, the difference was significant only in 500 Hz in the MCI group, and no significant differences were observed in the AD group. In addition, significant differences were observed between the normal subjects and AD patients with regard to the estimated ASSR thresholds with 2 modulation rates and 3 frequencies in both ears. A significant difference was observed between the normal and MCI groups at 2000 Hz, too. An increase in estimated 40 Hz ASSR thresholds in patients with AD and MCI suggests neural changes in auditory cortex compared to that in normal ageing. CONCLUSION: Auditory threshold estimation with low and high modulation rates by ASSR test could be a potentially helpful test for detecting cognitive impairment.

Mitochondrial impairments contribute to spatial learning and memory dysfunction induced by chronic tramadol administration in rat: Protective effect of physical exercise.

Despite the worldwide use of tramadol, few studies have been conducted about its effects on memory and mitochondrial function, and controversial results have been reported. Recently, there has been an increasing interest in physical exercise as a protective approach to neuronal and cognitive impairments. Therefore, the aim of this study was to investigate the effects of physical exercise on spatial learning and memory and brain mitochondrial function in tramadol-treated rats. After completion of 2-week (short-term) and 4-week (long-term) treadmill exercise regimens, male Wistar rats received tramadol (20, 40, 80mg/kg/day) intraperitoneally for 30days. Then spatial learning and memory was assessed by Morris water maze test (MWM). Moreover, brain mitochondrial function was evaluated by determination of mitochondrial reactive oxygen species (ROS) level, mitochondrial membrane potential (MMP), mitochondrial swelling and cytochrome c release from mitochondria. Chronic administration of tramadol impaired spatial learning and memory as well as brain mitochondrial function as indicated by increased ROS level, MMP collapse, increased mitochondrial swelling and cytochrome c release from mitochondria. Conversely, treadmill exercise significantly attenuated the impairments of spatial learning and memory and brain mitochondrial dysfunction induced by tramadol. The results revealed that chronic tramadol treatment caused memory impairments through induction of brain mitochondrial dysfunction. Furthermore, pre-exposure to physical exercise markedly mitigated these impairments through its positive effects on brain mitochondrial function.

Effect of Age, Gender and Hearing Loss on the Degree of Discomfort Due to Tinnitus.

INTRODUCTION: Tinnitus is one of the complex symptoms of hearing described as a phantom auditory sensation without any external stimulation. Due to the subjective nature of tinnitus, perception and discomfort of tinnitus vary among the patients. The main aim of this study is to investigate the effects of gender, age and the degree of hearing loss on discomfort due to tinnitus. METHODS: Eighteen patients with tinnitus, aged 21-72 years, (9 males and 9 females) were recruited. Tinnitus discomfort was investigated by Tinnitus Handicap Inventory (THI) questionnaire. Psychoacoustic assessments of tinnitus and auditory threshold assessments were evaluated using a 2-channel clinical audiometer. RESULTS: The results showed no significant correlation between THI scores with loudness matching (P=0.187), mean of auditory threshold (P=0.304), gender (P=0.93) and age (P=0.200). Also, no significant correlation was found between maximal level of hearing loss and pitch matching (P=0.208). CONCLUSION: The study findings suggests that tinnitus is not correlated with age, gender and hearing loss. Overall, tinnitus is a complicated clinical condition which its real impact and degree of discomfort are unclear. More investigation is needed to clarify the factors involving in tinnitus annoyance.

Low-Level Contrast Statistics of Natural Images Can Modulate the Frequency of Event-Related Potentials (ERP) in Humans.

Humans are fast and accurate in categorizing complex natural images. It is, however, unclear what features of visual information are exploited by brain to perceive the images with such speed and accuracy. It has been shown that low-level contrast statistics of natural scenes can explain the variance of amplitude of event-related potentials (ERP) in response to rapidly presented images. In this study, we investigated the effect of these statistics on frequency content of ERPs. We recorded ERPs from human subjects, while they viewed natural images each presented for 70 ms. Our results showed that Weibull contrast statistics, as a biologically plausible model, explained the variance of ERPs the best, compared to other image statistics that we assessed. Our time-frequency analysis revealed a significant correlation between these statistics and ERPs' power within theta frequency band (~3-7 Hz). This is interesting, as theta band is believed to be involved in context updating and semantic encoding. This correlation became significant at ~110 ms after stimulus onset, and peaked at 138 ms. Our results show that not only the amplitude but also the frequency of neural responses can be modulated with low-level contrast statistics of natural images and highlights their potential role in scene perception.

Central Obesity and Liver Iron Content: A Noninvasive Assessment in General Population by Magnetic Resonance Imaging.

BACKGROUND/AIM: Existing evidence points to an altered status of iron metabolism in obesity. We aimed to investigate whether central obesity is independently associated with estimated liver iron content (liver T2* value) in general population that used the noninvasive assessment method by MRI. METHODS: The study was carried out on 200 subjects randomly selected from the Golestan Cohort Study who underwent abdominal MRI. Quantitative T2* maps of entire cross-sectional area of liver were calculated using a semi-automated software for estimating the levels of iron content. Segmentation and calculation of visceral (VFA) and subcutaneous fat area (SFA) were also performed. RESULTS: There was no significant difference in mean liver T2* values between obese (body mass index, BMI >30 kg/m2) and non-obese (BMI ≤30 kg/m2) subjects. After controlling for other covariates, no statistically significant association was detected between liver T2* values and VFA, SFA and VFA/SFA ratio. The drop in the relative signal intensity as an indicator of steatosis and serum ferritin predicted liver T2* values that almost had the same strength (standardized ß of -0.41 and -0.41, respectively). CONCLUSIONS: Central obesity indices are not correlated with estimated liver iron content by MRI. Hepatic steatosis and serum ferritin seem to be the best predictors of hepatic T2* value. Since central obesity indices were not direct predictors of hepatic T2* value after the adjustment for confounding factors, it is possible that lipid accumulation in the liver locally, but not systematically, influences hepatic iron metabolism.

Comparing the effectiveness of the BPMAP (Blood Pressure Management Application) and usual care in self-management of primary hypertension and adherence to treatment in patients aged 30-60 years: study protocol for a randomized controlled trial.

BACKGROUND: Hypertension is one of the most important and well-known risk factors for cardiovascular diseases. Unfortunately, in spite of effective treatments, adherence to the regular use of drugs and other nondrug treatments, such as lifestyle improvement, is often poor. This study evaluates the effectiveness of an educational, supportive intervention - in the form of a Blood Pressure Management Application (BPMAP) - on self-management in patients with primary hypertension on controlling the determinant factors of hypertension, and on adherence to treatment. METHODS/DESIGN: A two-arm, parallel-design randomized controlled clinical trial will be conducted on 30 to 60 year-old patients with primary hypertension who are attending the Tehran Heart Center. One hundred and thirty-two (132) patients will be randomly assigned to the intervention and control (usual method) groups. The most important inclusion criteria are, having primary hypertension and being pharmacologically treated for it, and not having developed the complications of hypertension, such as myocardial infarction, cerebral stroke and cardiac insufficiency. The participants should be able to read Persian and be able to use the application. The most important outcomes of the study include adherence to treatment, weight control, and regular monitoring of blood pressure which are assessed in the primary assessment (baseline data questionnaire) and again at the 8th and 24th weeks. The intervention is a mobile application that has capabilities such as reminders and scientific and supportive information. DISCUSSION: This application has been programmed to reduce many of the nonadherence factors of hypertension treatment. Therefore, the findings may contribute to a rise in adherence to treatment. If proven to have an appropriate impact, it may be extended for use in the national hypertension control plan. TRIAL REGISTRATION: This study was registered in the Iran Randomized Clinical Trial Center under the number IRCT2015111712211N2 on 1 January 2016.

Assessment of Abdominal Fat Distribution in Non-Alcoholic Fatty Liver Disease by Magnetic Resonance Imaging: a Population-based Study.

BACKGROUND: To investigate the association between non-alcoholic fatty liver disease (NAFLD) and quantitative measures of central adiposity in the general population using a semi-automated method on magnetic resonance imaging (MRI) data. METHODS: Subjects were recruited from Golestan Cohort Study. Two groups of 120 individuals with and without fatty liver were randomly selected based on findings of ultrasound. Non-invasive diagnosis of NAFLD was made by combination of ultrasound and MRI. Various anthropometric indices including body mass index (BMI), waist-to-hip ratio (WHR) and waist-to-height ratio (WHtR) were measured. Segmentation and calculation of visceral (VFA) and subcutaneous fat area (SFA) were performed on three levels of MRI slices using semi-automated software. RESULTS: A total of 109 individuals fulfilled the NAFLD criteria, while 92 subjects were selected as the control group. All obesity measures, except for SFA, were significantly higher in subjects with NAFLD compared to controls. Significant associations were found between NAFLD and adiposity indices, except for SFA, with the highest odds ratio observed in WHR (OR: 3.37, CI: 1.40-3.70, P < 0.001). VFA also had the greatest correlation with ultrasound (r = 0.523, P < 0.001) and MRI (r = 0.546, P < 0.001) indicators of NAFLD. CONCLUSIONS: Quantitative measures of visceral adiposity are associated with NAFLD, while subcutaneous fat measures are poor indicators for identifying NAFLD. Compared to conventional anthropometric indices, VFA best correlates with ultrasound and MRI criteria of fatty liver.

Neural Correlates of Craving in Methamphetamine Abuse.

INTRODUCTION: Methamphetamine is a powerful psychostimulant that causes significant neurological impairments with long-lasting effects and has provoked serious international concerns about public health. Denial of drug abuse and drug craving are two important factors that make the diagnosis and treatment extremely challenging. Here, we present a novel and rapid noninvasive method with potential application for differentiation and monitoring methamphetamine abuse. METHODS: Visual stimuli comprised a series of images with neutral and methamphetamine-related content. A total of 10 methamphetamine abusers and 10 age-gender matched controls participated in the experiments. Event-related potentials (ERPs) were recorded and compared using a time window analysis method. The ERPs were divided into 19 time windows of 100 ms with 50 ms overlaps. The area of positive sections below each window was calculated to measure the differences between the two groups. RESULTS: Significant differences between two groups were observed from 250 to 500 ms (P300) in response to methamphetamine-related visual stimuli and 600 to 800 ms in response to neutral stimuli. CONCLUSION: This study presented a novel and noninvasive method based on neural correlates to discriminate healthy individuals from methamphetamine drug abusers. This method can be employed in treatment and monitoring of the methamphetamine abuse.

Abdominal fat distribution and carotid atherosclerosis in a general population: a semi-automated method using magnetic resonance imaging.

PURPOSE: Available evidence suggests functional differences in visceral and subcutaneous fat. We investigated the association between quantitative measures of central adiposity with indicators of carotid atherosclerosis including intima-media thickness (IMT) and plaque in a general population using a semi-automated method on magnetic resonance imaging (MRI) data. METHODS: In this cross-sectional study 200 subjects (52 % female), aged 50-77 years, were randomly selected from Golestan Cohort Study. Participants underwent ultrasound examination of carotid arteries and abdominal MRI. Segmentation and calculation of visceral (VFA) and subcutaneous fat area (SFA) were performed on three levels using semi-automated software. Various conventional anthropometric indices were also measured. RESULTS: Among 191 enrolled subjects, 77 (40 %) participants had IMT ≥0.8 mm. Carotid plaques were detected in 86 (44 %) subjects. In separate multivariate analysis models, unlike SFA and other anthropometric indices, the last tertile of VFA values was associated with at least threefold excess risk for IMT ≥0.8 mm (OR 3.8, 95 % CI 1.36-6.94, p = 0.02). There was no significant difference between mean values of categorized obesity indices in subjects with and without plaque, while participants in the highest tertile of VFA values were demonstrated to have higher risk of more than one plaque (OR 4.57, 95 % CI 1.03-20.11, p = 0.034). CONCLUSIONS: A higher amount of visceral fat, measured by a semi-automated technique using MRI, is associated with increased IMT and having more than one carotid plaque in a general population, while subcutaneous fat measures are poor indicators for identifying carotid atherosclerosis.

Slow oscillating transcranial direct current stimulation during sleep has a sleep-stabilizing effect in chronic insomnia: a pilot study.

Recent evidence suggests that lack of slow-wave activity may play a fundamental role in the pathogenesis of insomnia. Pharmacological approaches and brain stimulation techniques have recently offered solutions for increasing slow-wave activity during sleep. We used slow (0.75 Hz) oscillatory transcranial direct current stimulation during stage 2 of non-rapid eye movement sleeping insomnia patients for resonating their brain waves to the frequency of sleep slow-wave. Six patients diagnosed with either sleep maintenance or non-restorative sleep insomnia entered the study. After 1 night of adaptation and 1 night of baseline polysomnography, patients randomly received sham or real stimulation on the third and fourth night of the experiment. Our preliminary results show that after termination of stimulations (sham or real), slow oscillatory transcranial direct current stimulation increased the duration of stage 3 of non-rapid eye movement sleep by 33 ± 26 min (P = 0.026), and decreased stage 1 of non-rapid eye movement sleep duration by 22 ± 17.7 min (P = 0.028), compared with sham. Slow oscillatory transcranial direct current stimulation decreased stage 1 of non-rapid eye movement sleep and wake time after sleep-onset durations, together, by 55.4 ± 51 min (P = 0.045). Slow oscillatory transcranial direct current stimulation also increased sleep efficiency by 9 ± 7% (P = 0.026), and probability of transition from stage 2 to stage 3 of non-rapid eye movement sleep by 20 ± 17.8% (P = 0.04). Meanwhile, slow oscillatory transcranial direct current stimulation decreased transitions from stage 2 of non-rapid eye movement sleep to wake by 12 ± 6.7% (P = 0.007). Our preliminary results suggest a sleep-stabilizing role for the intervention, which may mimic the effect of sleep slow-wave-enhancing drugs.

Liver enzyme levels and hepatic iron content in Fatty liver: a noninvasive assessment in general population by T2* mapping.

RATIONALE AND OBJECTIVES: Existing evidence suggests potential contribution of iron in pathogenesis of nonalcoholic fatty liver disease (NAFLD). We aimed to investigate whether hepatic iron content correlates with liver enzyme levels in NAFLD using a noninvasive magnetic resonance imaging (MRI) technique. MATERIALS AND METHODS: Subjects from Golestan Cohort Study were randomly selected. Diagnosis of NAFLD was made by combination of ultrasound and MRI. Subjects with NAFLD were divided into two groups with high (H-NAFLD) and low (L-NAFLD) enzyme level according to 95th percentile of alanine aminotransferase (ALT) value in normal population. Quantitative T2* maps of entire cross-sectional area of liver were calculated on pixel-by-pixel basis using a semiautomated software. RESULTS: A total of 207 subjects were enrolled. Mean T2* values were significantly lower in NAFLD group than controls (P < .001) indicating higher iron content. Male subjects with H-NAFLD had statistically lower T2* values than those with L-NAFLD in multivariate analysis (odds ratio, 0.74; 95% confidence interval [CI], 0.58-0.95), whereas this was not observed in women. Unlike women, there was significant negative correlation between ALT levels and T2* values in men with H-NAFLD (r = -0.66, P = .01). Every 1-millisecond decrement in T2* value was associated with 6.37 IU/L increase in ALT level (95% CI, 1.8-10.9, P = .01) in men with H-NAFLD. CONCLUSIONS: Higher hepatic iron in men with H-NAFLD, estimated by T2* mapping, may support the role of iron in possible progression of simple steatosis to nonalcoholic steatohepatitis. Lack of such correlation in women could be attributed to relatively lower iron storage or other mechanisms rather than iron.