Function In Normal Subjects Research Articles

The Effect of Focused Vibration on Tibialis Anterior Function in Normal Subjects

Category: Basic Sciences/Biologics; Other Introduction/Purpose: Foot drop is a debilitating condition which may be caused by peripheral nerve pathology. Focused vibration therapy (FVT) is a novel treatment in this setting which aims to improve the response of muscle motor units to nervous stimuli, improving muscle function and rehabilitation potential. This study investigates the effect of FVT on tibialis anterior (TA) function in normal subjects to determine the optimal timing of application. Methods: Fifteen normal subjects with mean age 25.47±3.27 years and BMI of 21.93±1.54kg/m2 were recruited. Using surface electromyography (EMG), a rotary potentiometer, video analysis (KINOVEA software), and force gauges, the activity of TA, ankle range of movement (ROM), and force at maximal isometric voluntary contraction (MVC) in dorsiflexion were measured. Baseline TA strength was recorded, and participants then performed a series of dorsiflexion exercises to induce fatigue. Strength measurements were repeated after a 5-minute rest period (control). This process was repeated with FVT applied before exercise (FVBE) and after exercise (during the rest period, FVAE). FVT was delivered over the TA muscle belly at 75Hz / 0.4mm amplitude. Data was analysed using ANOVA. Results: There was no significant change in EMG readings or dorsiflexion ROM between baseline, control and FVBE/FVAE measurements. Compared to baseline, MVC increased by 10.87N (6.6%) after FVBE (p=0.034) and 13.87N (8.4%) after FVAE (p=0.034). Compared to control, MVC did not increase significantly with FVBE, but did increase by 7.70N (4.3%) following FVAE (p=0.049). Conclusion: FVT improved the MVC of TA - this was most pronounced when FVT was applied during the recovery phase, after exercise. The lack of EMG / ROM improvement is expected in normal subjects. Our results suggest that FVT is more effective than passive rest and may enhance muscle strength recovery. Further work will investigate the optimal dose of FVT and response in patients with pathology.

SPARC: Correlation between Patient Characteristics in Gastrointestinal Evaluation using Principal Component Analysis

Introductionanorectal function is complex. Assessment of anorectal physiology and diagnostics for anorectal disorders face problems due to inconsistent results with different technologies and huge inter‐subject variability. This limits development of therapeutic strategies. Devices used to evaluate anorectal function include Fecobionics, EndoFLIP, Anorectal manometry and Ultrasound. The goal of this study was to find correlation in patient characteristics based on data obtained with these measurements.Methodsthe four tests mentioned above were used to evaluate anorectal function in normal subjects and patients with fecal incontinence (FI) or constipation. The data were cleaned by replacing unknown values with the average of measurements, and they were standardized. In total there were 90 measurements and 35 features. The collected data included sex, age (60.0±14.3 years), weight (59.0±9.0 kg), height (1.6±0.1m), FI score (16.8±12.8 with normal values =< 5), constipation score (6.5±4.4 with normal values =< 8), anorectal maximum pressure (46.9±10.1 mmHg), resting pressure (61±25.8 mmHg), expel time (46.3±63.2s), and absence or presentation of rectoanal inhibitory reflex (RAIR), etc. Principal component analysis (PCA) was used to find the contribution of each reduced feature in variance of data and the correlation between features, utilizing singular value decomposition. We used Python and its libraries.Results and Discussionthe variance in data was mostly explained using 25 PCs. The percentage of cumulative variance explained by up to the 1th, 25th and 35th PC was 15%, 98% and 100%, respectively. The PCs provided insights about the relation between features. For example, according to the first PC the maximum pressure, resting pressure, maximum tolerance and age were positively correlated. Also, weight, absence of RAIR and constipation score were positively correlated. However, the latter group of parameters were negatively correlated to the former group. Because the number of patients used in this study were limited results should be interpreted with caution. However, more data are currently being collected, which will be included in our analysis. We plan to extend our analysis to cluster patient data using machine learning.Conclusionsin this study we analyzed data gathered in anorectal evaluation using PCA. Data obtained provided insights about relation between characteristics of the patients. Analysis of data obtained in anorectal evaluation will help to better understand factors involved in anorectal and other gastrointestinal disorders, which could lead to better preventive, diagnostic and therapeutic strategies.Support or Funding InformationNIH SPARC fundingAcknowledgementsNIH SPARC funding.

Variability of lung function and respiratory muscles power in healthy and asthmatic subjects

Airway function is one of the many biologic functions that exhibit circadian variability over 24-h periods. Studies of circadian variability of lung function in normal subjects as well as asthmatics are particularly scarce, and those of MEP and MIP are unknown. The aim of this study to determine circadian variation in lung function (FVC, FEV1 and PEFR) and respiratory muscle pressures(MEP and MIP) for measurement of respiratory muscle power at 6:00am (early morning),12:00midday, 6:00pm( evening) and 12:00 midnight in healthy subjects and in patients with mild asthma at 6:00am and 6:00pm , to elaborate on the possibility of using MEP and MIP variability as a new diagnostic test for asthma. This is a cross sectional study performed in Khartoum, the capital of Sudan during December 2010. Thirty healthy, symptoms free non smokers normal subjects aged 20-64 years selected randomly and 15 mild asthmatics, clinically free during the time of study aged 19-49 years were included in the study. There is significant drop in healthy subjects early in the morning compared to 6:00pm, the drop in FVC was 9.75%, in FEV1 was 8.79%, in PEFR was 8.44%, in MEP was 10.04%, and in MIP was 17.57%. There is also significant drop in asthmatics early in the morning in MEP and MIP (21.76%, 27.57% respectively), is comparable to FEV1 (22.56%) and PEFR (23.86%). The sensitivity and specificity of variability for MEP (53%, 77%) and MIP (60%, 63%) comparable to sensitivity and specificity of FEV1 variability (40%, 86%) and PEFR variability (46%, 73%). The obtained comparable results of MEP, MIP variability to FEV1, PEFR variability in normal and asthmatic subjects could imply that MEP & MIP can be used in assessing airway calibre as in asthma. The study concluded that MEP & MIP variability could be sensitive tests to confirm asthma diagnosis.

Cognitive functions and white matter lesions on magnetic resonance images in a sample of normal Iranian population with cardiovascular risk factors

Due to a suggestive three-way relationship between brain structural disorders, microvascular lesions, and cognitive impairments, we aimed to examine the association of the volume and number of white matter hyperintensity lesions and lacunar infarcts with cognitive impairment among patients with cardiovascular risk factors in a sample of the Iranian population. This study was conducted on a total number of 156 normal subjects aged 30-74 years with cardiovascular risk factors. We used the Framingham general cardiovascular risk factors prediction model to calculate the likelihood of each risk factor. The total number of lacunar infarcts and the volume of white matter hyperintensity lesion were calculated in brain magnetic resonance imaging. Cognition status was assessed using the Montreal Cognitive Assessment questionnaire. An adverse association was revealed between Montreal Cognitive Assessment score and different cardiovascular risk profiles including the Framingham body mass index score ( p < 0.001) and the Framingham lipid score ( p < 0.001). The total volume of white matter hyperintensity was negatively associated with total Montreal Cognitive Assessment cognition score ( p < 0.001). Our study also showed an adverse association between total number of lacunar infarcts and total Montreal Cognitive Assessment cognition score ( p = 0.038) and with some cognition components including memory ( p = 0.013), attention ( p = 0.037), abstraction ( p = 0.046), and orientation ( p = 0.002). Periventricular lesions are associated with impaired memory, language, and visuoconstruction while subcortical lesions are associated with impairment in naming, attention, language, and abstraction functions in normal subjects with cardiovascular risk factors but without cardiovascular or cerebrovascular disorders.

Effects of transcranial magnetic brain stimulation with the maximum voluntary muscle contraction (TMS with MVC) on cognitive and motor function in normal subjects

Background: Previous studies reported that muscle exercise could improve cognitive function in elder persons.

Structural cerebellar correlates of cognitive and motor dysfunctions in cerebellar degeneration.

See King et al. (doi:10.1093/aww348) for a scientific commentary on this article.Detailed mapping of clinical dysfunctions to the cerebellar lobules in disease populations is necessary to establish the functional significance of lobules implicated in cognitive and motor functions in normal subjects. This study constitutes the first quantitative examination of the lobular correlates of a broad range of cognitive and motor phenomena in cerebellar disease. We analysed cross-sectional data from 72 cases with cerebellar disease and 36 controls without cerebellar disease. Cerebellar lobule volumes were derived from a graph-cut based segmentation algorithm. Sparse partial least squares, a variable selection approach, was used to identify lobules associated with motor function, language, executive function, memory, verbal learning, perceptual organization and visuomotor coordination. Motor dysfunctions were chiefly associated with the anterior lobe and posterior lobule HVI. Confrontation naming, noun fluency, recognition, and perceptual organization did not have cerebellar associations. Verb and phonemic fluency, working memory, cognitive flexibility, immediate and delayed recall, verbal learning, and visuomotor coordination were variably associated with HVI, Crus I, Crus II, HVII B and/or HIX. Immediate and delayed recall also showed associations with the anterior lobe. These findings provide preliminary anatomical evidence for a functional topography of the cerebellum first defined in task-based functional magnetic resonance imaging studies of normal subjects and support the hypotheses that (i) cerebellar efferents target frontal lobe neurons involved in forming action representations and new search strategies; (ii) there is greater involvement of the cerebellum when immediate recall tasks involve more complex verbal stimuli (e.g. longer words versus digits); and (iii) it is involved in spontaneous retrieval of long-term memory. More generally, they provide an anatomical background for studies that seek the mechanisms by which cognitive and motor dysfunctions arise from cerebellar degeneration. Beyond replicating these findings, future research should employ experimental tasks to probe the integrity of specific functions in cerebellar disease, and new imaging methods to quantitatively map atrophy across the cerebellum.

Multi-cycle Reconstruction of Cardiac MRI for the Analysis of Inter-ventricular Septum Motion During Free Breathing.

Small variations in left-ventricular preload due to respiration produce measurable changes in cardiac function in normal subjects. We show that this mechanism is altered in patients with reduced ejection fraction (EF), hypertrophy, or volume-loaded right ventricle (RV). We propose a multi-dimensional retrospective image reconstruction, based on an adaptive, soft classification of data into respiratory and cardiac phases, to study these effects.

Fasting in Ramadan Affects Cognitive and Physiological Function in Normal Subjects (Pilot Study)

Purpose: Our study aimed to investigate the effects of Ramadan fasting on cognitive and physiological function in a group of healthy Muslim subjects. Methods: We measured demographic, physiological (blood pressure), and cognitive function including attention switching task (AST) and delayed matching to sample (DMS) using the Cambridge Neuropsychological Test Automated Battery (CANTAB) at two periods of the study (before Ramadan, at the second week in Ramadan) in 15 subjects. Results: During fasting, performance on the AST test improved significantly for switching cost (p = 0.030) and for congruent condition of AST task (p = 0.043), for diastolic pressure decreased (p = 0.069) in healthy subjects. There was no significant effect for incongruent condition and number of errors and percent to complete task for DMS test and systolic blood pressure. Conclusions: The results suggest that Ramadan fasting is associated with significant changes in cognition, and causes a drop in diastolic blood pressure in healthy subject.

The right ventricle: always normal in normal subjects?

Right ventricular (RV) structure and function serve as important indicators of a wide spectrum of heart diseases such as congenital heart disease, pulmonary hypertension, hypertrophic cardiomyopathy and arrhythmogenic right ventricular cardiomyopathy/disease (ARVC/D) [1–3]. Over the past years cardiac magnetic resonance imaging (CMR) has proven itself as the preferred imaging modality of choice to evaluate RV anatomy, structure, texture, motion and function [4–9]. In the study by Quick et al. [10], published in the current issue of the Netherlands Heart Journal, a quantitative analysis of normal variations in RV wall motion was evaluated in healthy subjects using CMR. The study population consisted of 65 consecutive patients referred for the evaluation of cardiac function by 3 Tesla-CMR. All subjects were shown to be free of heart disease based on the currently available guidelines for CMR. Balanced steady-state free-precession images were obtained and regional RV wall motion was evaluated and classified based on a standardised segmental model for the right ventricle. In 59 out of 65 subjects (>90 %) wall motion abnormalities of the right ventricle were observed. Wall motion abnormalities were predominantly seen in the apico-lateral segments (72 %) when compared with the medio-lateral (24 %) and infero-lateral segments (4 %). Dyskinesia was the most frequent wall motion disorder (62 %), followed by hypokinesia (21 %) and bulging (17 %). The authors concluded that RV wall motion abnormalities are common in subjects supposed to be normal, indicating that one should be aware of the notion that non-pathological wall motion disorders can easily be mistaken for a pathological regional wall motion abnormality, particularly in patients with ARVC where –according to the authors- to date, clear wall motion criteria are lacking. The study is certainly very interesting in the sense that the right ventricle in normal subjects does not always appear normal when visualised by CMR. Especially, regional wall motion abnormalities are predominantly seen in the apico-lateral segments. However, the study warrants the following three comments. First, also acknowledged by the authors, the study was based on a small patient population. As a result, the description of normal variations in RV morphology as observed by CMR are not necessarily absolute and should only be regarded as hypothesis-generating for studying larger patient samples. Second, according to the authors, there is supposedly no in-depth knowledge on RV motion in healthy subjects. This is an obvious understatement as already in 2004 Pennell’s group (London, UK) showed that CMR demonstrated good inter-study reproducibility for RV function parameters in 20 healthy subjects, in 20 patients with heart failure, and in 20 patients with hypertrophy, suggesting that CMR is reliable for serial RV assessment [11]. In 2008, Youssef et al. [12] showed in 21 healthy subjects that the strain-encoding CMR technique allowed for rapid quantification of RV regional function with low intra- and inter-observer variability, permitting accurate quantification of regional strain in patients with RV dysfunction. Rather recently, Von Knobelsdorff-Brenkenhoff et al. [13], in nine healthy subjects, showed that fast-gradient echo cine imaging of the RV at 7 Tesla-CMR was feasible and provided good image quality; RV dimensions and function were comparable with steady-state free-precession at 1.5 Tesla-CMR as gold standard. Doesch et al. [14] showed in 20 healthy subjects that CMR-derived measurement of the tricuspid annular plane systolic excursion with a reference point outside the ventricle (TAPSEout) might be used for screening RV motion; however, the detection of subtle changes in RV function requires the 3D volumetric CMR approach. Third, and most importantly, Quick et al. [10] rather firmly state, that -particularly in ARVC patients- ‘to date clear wall motion criteria are lacking’. However, the revised ARVC/D diagnostic Task Force Criteria, already dating from 2010, incorporate clear CMR-defined cut-off values for RV ejection fraction and RV end-diastolic volume for ARVC [3, 15]. More specifically, the 2010 ARVC/D Task Force Criteria include the following parameters for CMR: 1) regional RV akinesia or dyskinesia or dyssynchronous RV contraction, 2) ratio of RV end-diastolic volume to BSA ≥110 mL/m2 (male) or ≥100 mL/m2 (female), or RV ejection fraction ≤40 %. Used in this way, CMR-derived RV ejection fraction can help in distinguishing ARVC/D from both normal subjects and/or from the physiological cardiac adaptation in athletes [3, 15]. To summarise, despite the above-mentioned critical comments, the study by Quick et al. [10] is a valuable contribution to our understanding of CMR-derived RV function in normal subjects. The study clearly shows that RV wall motion abnormalities may occur both in normal subjects and in diseased patients, in particular those with ARVC. Fortunately, CMR-derived parameters, as defined by the 2010 ARVC/D Task Force Criteria, may provide a major discriminatory role.

The role of endothelial nitric oxide synthase coupling status during acute hyperglycemia as determined by real‐time measurements of blood nitric oxide and hydrogen peroxide in rat (832.2)

Acute hyperglycemia impairs vascular dilatory function in normal subjects. Normally, vascular endothelial function depends on nitric oxide (NO) production from coupled eNOS in the presence of cofactor 5,6,7,8‐tetrahydrobiopterin (BH4). By contrast, 7,8‐dihydrobiopterin (BH2, oxidized form of BH4) and/or lack of L‐arginine (eNOS substrate) causes eNOS uncoupling to produce superoxide (SO), which can be quickly converted to hydrogen peroxide (H2O2). The role of eNOS coupling status in mediating acute hyperglycemia‐induced vascular dysfunction is not known. We simultaneously measured blood NO and H2O2 during the infusion of saline (control), or 20% glucose with or without BH4 (MW=314 g/mol, 6.5 mg/kg), or L‐arginine (MW=211 g/mol, 600 mg/kg), or BH2 (MW=239 g/mol, 4 mg/kg) by NO or H2O2 microsensors (100 µm, WPI Inc.) from the femoral veins of male Sprague‐Dawley rats. We found that acute hyperglycemia (200 mg/dL, n=6) significantly increased blood H2O2 and reduced blood NO levels compared to the saline group over a 3 hr. period (n=7, p&lt;0.05). By contrast, BH4 (n=6), or L‐arginine (n=5‐6), not BH2 (n=6‐7), significantly reduced blood H2O2 and improved vascular NO levels (p&lt;0.05). This study provides novel evidence indicating that eNOS uncoupling during acute hyperglycemia causes endothelial dysfunction and oxidative stress. Promotion of eNOS coupling may be beneficial to maintain normal vascular function.Grant Funding Source: Supported by Center for Chronic Disorders of Aging and Department of Bio‐Medical Sciences at PCOM

Central Retinal Enrichment Supplementation Trials (CREST): Design and Methodology of the CREST Randomized Controlled Trials

Purpose: The Central Retinal Enrichment Supplementation Trials (CREST) aim to investigate the potential impact of macular pigment (MP) enrichment, following supplementation with a formulation containing 10 mg lutein (L), 2 mg zeaxanthin (Z) and 10 mg meso-zeaxanthin (MZ), on visual function in normal subjects (Trial 1) and in subjects with early age-related macular degeneration (AMD; Trial 2).Methods: CREST is a single center, double-blind, randomized clinical trial. Trial 1 (12-month follow-up) subjects are randomly assigned to a formulation containing 10 mg L, 10 mg MZ and 2 mg Z (n = 60) or placebo (n = 60). Trial 2 (24-month follow-up) subjects are randomly assigned to a formulation containing 10 mg L, 10 mg MZ, 2 mg Z plus 500 mg vitamin C, 400 IU vitamin E, 25 mg zinc and 2 mg copper (Intervention A; n = 75) or 10 mg L and 2 mg Z plus 500 mg vitamin C, 400 IU vitamin E, 25 mg zinc and 2 mg copper (Intervention B; n = 75). Contrast sensitivity (CS) at 6 cycles per degree represents the primary outcome measure in each trial. Secondary outcomes include: CS at other spatial frequencies, MP, best-corrected visual acuity, glare disability, photostress recovery, light scatter, cognitive function, foveal architecture, serum carotenoid concentrations, and subjective visual function. For Trial 2, AMD morphology, reading speed and reading acuity are also being recorded.Conclusions: CREST is the first study to investigate the impact of supplementation with all three macular carotenoids in the context of a large, double-blind, randomized clinical trial.

Multidirectional Global Left Ventricular Systolic Function in Normal Subjects and Patients with Hypertension: Multicenter Evaluation

The aim of this multicenter study was to determine the normal ranges and the clinical relevance of multidirectional systolic parameters to evaluate global left ventricular (LV) systolic function. Three hundred twenty-three healthy adult subjects prospectively included at 10 centers and a cohort of 310 patients with hypertension were analyzed. Multidirectional global LV systolic function was analyzed using two-dimensional speckle-tracking echocardiography by means of two indices: longitudinal-circumferential systolic index (the average of longitudinal and circumferential global systolic strain) and global systolic index (the average of longitudinal, circumferential, and radial global systolic strain). The ranges of values of the multidirectional systolic parameters in healthy subjects were -21.22 ± 2.22% for longitudinal-circumferential systolic index and 29.71 ± 5.28% for global systolic index. In addition, the lowest expected values of these multidirectional indices were determined in this population (calculated as -1.96 SDs from the mean): -16.86% for longitudinal-circumferential systolic index and 19.36% for global systolic index. Concerning the clinical relevance of these measurements, these indices indicated the presence of subtle LV global systolic dysfunction in patients with hypertension, even though LV global longitudinal systolic strain and LV ejection fraction were normal. Moreover, in these patients, functional class (dyspnea [New York Heart Association classification]) was inversely related to both the longitudinal-circumferential index and the global systolic index. In the present multicenter study analyzing a large cohort of healthy subjects and patients with hypertension, the normal range and the clinical relevance of multidirectional systolic parameters to evaluate global LV systolic function have been determined.

Joint symbolic analyses of heart rate, blood pressure, and respiratory dynamics

IntroductionThe dynamics of cardiovascular variables are modulated by respiration. The aim of this study was to assess baroreflex function in normal subjects based on the joint symbolic dynamics of heart rate, blood pressure and respiration. MethodsECG, continuous blood pressure and respiration were recorded in ten healthy subjects during rest in the supine position and upon standing. Beat-to-beat time series of heart rate, systolic blood pressure and respiratory phase were extracted and transformed into binary symbol sequences. Words of length two that were reflective of baroreflex activity were statistically analysed with respect to the respiratory phase. ResultsSymbolic analysis showed a significant influence of the respiratory phase on the occurrence of baroreflex patterns. Upon standing, the frequency of baroreflex words increased and the effect of respiration appeared to be reduced. ConclusionsSymbolic dynamics provide a simple representation of cardiovascular dynamics and may be useful for assessing baroreflex function.

Gender differences between left and right ventricular diastolic function in normal subjects

Gender differences between left and right ventricular diastolic function in normal subjects

Impact of age on diastolic function and left atrial volume and function in normal subjects assessed by two-dimensional speckle tracking echocardiography

Impact of age on diastolic function and left atrial volume and function in normal subjects assessed by two-dimensional speckle tracking echocardiography

Fluticasone Induces Epithelial Injury and Alters Barrier Function in Normal Subjects.

ObjectiveThe airway epithelium has a number of roles pivotal to the pathogenesis of asthma, including provision of a physical and immune barrier to the inhaled environment. Dysregulated injury and repair responses in asthma result in loss of airway epithelial integrity. Inhaled corticosteroids are a corner stone of asthma treatment. While effective in controlling asthma symptoms, they fail to prevent airway remodeling. Direct cytopathic effects on the airway epithelium may contribute to this.MethodsThis study examined the effects of a 4-week treatment regimen of inhaled fluticasone 500 μg twice daily in healthy human subjects. Induced sputum was collected for cell counts and markers of inflammation. Barrier function was examined by diethylenetriaminepentacetic acid (DTPA) clearance measured by nuclear scintillation scan, and albumin concentration in induced sputum.ResultsSteroid exposure resulted in epithelial injury as measured by a significant increase in the number of airway epithelial cells in induced sputum. There was no change in airway inflammation by induced sputum inflammatory cell counts or cytokine levels. Epithelial shedding was associated with an increase in barrier function, as measured by both a decrease in DTPA clearance and decreased albumin in induced sputum. This likely reflects the normal repair response.ConclusionInhaled corticosteroids cause injury to normal airway epithelium. These effects warrant further evaluation in asthma, where the dysregulated repair response may contribute to airway remodeling.

Effect of schizophrenia risk-associated alleles in SREB2 (GPR85) on functional MRI phenotypes in healthy volunteers.

Genetic variants in GPR85 (SREB2: rs56080411 and rs56039557) have been associated with risk for schizophrenia. Here, we test the hypothesis that these variants impact on brain function in normal subjects, measured with functional magnetic resonance imaging (fMRI) paradigms that target regions with greatest SREB2 expression (hippocampal formation and amygdaloid complex). During a facial emotion recognition paradigm, a significant interaction of rs56080411 genotype by sex was found in the left amygdaloid complex (male risk allele carriers showed less activation than male homozygotes for the non-risk allele, while females showed the opposite pattern). During aversive encoding of an emotional memory paradigm, we found that risk allele carriers for rs56080411 had greater activation in the right inferior frontal gyrus. Trends in the same direction were present for rs56039557 in the right occipital cortex and right fusiform gyrus. During a working memory paradigm, a significant sex-by-genotype interaction was found with male risk allele carriers of rs56080411 having inefficient activation within the left dorsolateral prefrontal cortex (DLPFC), compared with same sex non-risk carriers, while females revealed an opposite pattern, despite similar levels of performance. These data suggest that risk-associated variants in SREB2 are associated with phenotypes similar to those found in patients with schizophrenia in the DLPFC and the amygdala of males, while the pattern is opposite in females. The findings in females and during the emotional memory paradigm are consistent with modulation by SREB2 of brain circuitries implicated in mood regulation and may be relevant to neuropsychiatric conditions other than schizophrenia.

An empirical comparison of surface-based and volume-based group studies in neuroimaging

Being able to detect reliably functional activity in a population of subjects is crucial in human brain mapping, both for the understanding of cognitive functions in normal subjects and for the analysis of patient data. The usual approach proceeds by normalizing brain volumes to a common three-dimensional template. However, a large part of the data acquired in fMRI aims at localizing cortical activity, and methods working on the cortical surface may provide better inter-subject registration than the standard procedures that process the data in the volume. Nevertheless, few assessments of the performance of surface-based (2D) versus volume-based (3D) procedures have been shown so far, mostly because inter-subject cortical surface maps are not easily obtained. In this paper we present a systematic comparison of 2D versus 3D group-level inference procedures, by using cluster-level and voxel-level statistics assessed by permutation, in random effects (RFX) and mixed-effects analyses (MFX). We consider different schemes to perform meaningful comparisons between thresholded statistical maps in the volume and on the cortical surface. We find that surface-based multi-subject statistical analyses are generally more sensitive than their volume-based counterpart, in the sense that they detect slightly denser networks of regions when performing peak-level detection; this effect is less clear for cluster-level inference and is reduced by smoothing. Surface-based inference also increases the reliability of the activation maps.

Short-Term Hyperinsulinemia and Hyperglycemia Increase Myocardial Lipid Content in Normal Subjects

Increased myocardial lipid content (MYCL) recently has been linked to the development of cardiomyopathy in diabetes. In contrast to steatosis in skeletal muscle and liver, previous investigations could not confirm a link between MYCL and insulin resistance. Thus, we hypothesized that cardiac steatosis might develop against the background of the metabolic environment typical for prediabetes and early type 2 diabetes: combined hyperglycemia and hyperinsulinemia. Therefore, we aimed to prove the principle that acute hyperglycemia (during a 6-h clamp) affects MYCL and function (assessed by 1H magnetic resonance spectroscopy and imaging) in healthy subjects (female subjects: n = 8, male subjects: n = 10; aged 28 ± 5 years; BMI 22.4 ± 2.6 kg/m2). Combined hyperglycemia (202.0 ± 10.6 mg/dL) and hyperinsulinemia (110.6 ± 59.0 μU/mL) were, despite insulin-mediated suppression of free fatty acids, associated with a 34.4% increase in MYCL (baseline: 0.20 ± 0.17%, clamp: 0.26 ± 0.22% of water signal; P = 0.0009), which was positively correlated with the area under the curve of insulin (R = 0.59, P = 0.009) and C-peptide (R = 0.81, P < 0.0001) during the clamp. Furthermore, an increase in ejection fraction (P < 0.0001) and a decrease in end-systolic volume (P = 0.0002) were observed, which also were correlated with hyperinsulinemia. Based on our findings, we conclude that combined hyperglycemia and hyperinsulinemia induce short-term myocardial lipid accumulation and alterations in myocardial function in normal subjects, indicating that these alterations might be directly responsible for cardiac steatosis in metabolic diseases.

Exercise using tongue‐holding swallow does not improve swallowing function in normal subjects

We evaluated the effects of repetitive tongue-holding swallow (THS) as an exercise for improving swallowing function. Twenty healthy subjects were randomly divided into two groups. One group [THS group (THSG)] performed the tongue-holding manoeuvre every 5s for 20min. The other group (normal swallow group) swallowed without tongue-holding for the same length of time as a control. Twenty sessions of training were performed for 4weeks. All participants also had a videofluoroscopic swallowing study for analysing the biomechanical parameters of swallowing (hyolaryngeal movement, posterior pharyngeal wall movement and the pharyngeal constriction ratio). After 4weeks of training, none of the biomechanical parameters changed in either group. Exercise using THS did not affect swallowing function in normal subjects.