Abnormal Functional Patterns Research Articles

The relationship between putamen-SMA functional connectivity and sensorimotor abnormality in ESRD patients.

The basal ganglia (BG) are composed of several nuclei involved in neural processing associated with integration of sensory and motor information. Recent neuroimaging studies implicated its key role in control of voluntary motor function. As the sensorimotor abnormality is common among the end-stage renal disease (ESRD) population, in the current study, we aimed to investigate the abnormal structure and functional connectivity patterns of BG in ESRD patients. Twenty-nine ESRD and twenty-nine age and gender-matched healthy controls (HC) were enrolled to compare the volume of the subsets in the BG (e.g., caudate nucleus, putamen and globus pallidus) by using the VBM analysis; resting-state functional connectivity was analyzed by a seed-based method. Compared with the HC group, ESRD patients had a smaller volume in the right putamen. Taking the right putamen as a seed region, we further found reduced functional connectivity in patients mainly between the putamen and supplementary motor area (SMA), insula, posterior mid-cingulate gyrus, and primary motor cortex. In ESRD group, the severity score of restless legs syndrome was negatively correlated with putamen-SMA functional connectivity, while the hemoglobin level was positively correlated with functional connectivity degree between the putamen and SMA. Our results revealed an abnormal volume of the putamen and its decreased functional connectivity patterns during resting state in ESRD with sensorimotor abnormalities. These preliminary results indicated that the decreased functional connectivity in putamen-SMA was associated with sensorimotor abnormalities, and anemia was correlated with this abnormal functional pattern in ESRD patients.

Whole-brain connectivity analysis and classification of spinocerebellar ataxia type 7 by functional MRI

BackgroundSpinocerebellar ataxia type 7 (SCA7) is a genetic disorder characterized by degeneration of the motor and visual systems. Besides neural deterioration, these patients also show functional connectivity changes linked to the degenerated brain areas. However, it is not known if there are functional connectivity changes in regions not necessarily linked to the areas undergoing structural deterioration. Therefore, in this study we have explored the whole-brain functional connectivity of SCA7 patients in order to find the overall abnormal functional pattern of this disease. Twenty-six patients and age-and-gender-matched healthy controls were recruited. Whole-brain functional connectivity analysis was performed in both groups. A classification algorithm was used to find the discriminative power of the abnormal connections by classifying patients and healthy subjects.ResultsNineteen abnormal functional connections involving cerebellar and cerebral regions were selected for the classification stage. Support vector machine classification reached 92.3% accuracy with 95% sensitivity and 89.6% specificity using a 10-fold cross-validation. Most of the selected regions were well known degenerated brain regions including cerebellar and visual cortices, but at the same time, our whole-brain connectivity analysis revealed new regions not previously reported involving temporal and prefrontal cortices.ConclusionOur whole-brain connectivity approach provided information that seed-based analysis missed due to its region-specific searching method. The high classification accuracy suggests that using resting state functional connectivity may be a useful biomarker in SCA 7.Electronic supplementary materialThe online version of this article (doi:10.1186/2053-8871-1-2) contains supplementary material, which is available to authorized users.

Stress Impact on Resting State Brain Networks

Resting state brain networks (RSNs) are spatially distributed large-scale networks, evidenced by resting state functional magnetic resonance imaging (fMRI) studies. Importantly, RSNs are implicated in several relevant brain functions and present abnormal functional patterns in many neuropsychiatric disorders, for which stress exposure is an established risk factor. Yet, so far, little is known about the effect of stress in the architecture of RSNs, both in resting state conditions or during shift to task performance. Herein we assessed the architecture of the RSNs using functional magnetic resonance imaging (fMRI) in a cohort of participants exposed to prolonged stress (participants that had just finished their long period of preparation for the medical residence selection exam), and respective gender- and age-matched controls (medical students under normal academic activities). Analysis focused on the pattern of activity in resting state conditions and after deactivation. A volumetric estimation of the RSNs was also performed. Data shows that stressed participants displayed greater activation of the default mode (DMN), dorsal attention (DAN), ventral attention (VAN), sensorimotor (SMN), and primary visual (VN) networks than controls. Importantly, stressed participants also evidenced impairments in the deactivation of resting state-networks when compared to controls. These functional changes are paralleled by a constriction of the DMN that is in line with the pattern of brain atrophy observed after stress exposure. These results reveal that stress impacts on activation-deactivation pattern of RSNs, a finding that may underlie stress-induced changes in several dimensions of brain activity.

Rehabilitation and Neuromuscular Coordination of the Knee

Neuromuscular control of the active and passive restraints of the knee determine normal function. Injury interferes with this normal control and results in the development of abnormal functional patterns which the patient recognizes as instability. Rehabilitation must help regain the normal function by overcoming these abnormal patterns.

LUNG FUNCTION IN DIFFUSE INTERSTITIAL LUNG DISEASE OF UNKNOWN CAUSE

To examine the role of lung function tests in diagnosis and management of patients with diffuse interstitial lung disease (DILD) we measured total lung capacity (TLC), gas transfer (Tl), lung distensibility and arterial saturation (SaO2) and ventilation during progressive exercise in 24 patients with DILD including 18 with biopsy confirmation. Tl was decreased in all patients, in 21/24 there was progressive hypoxia with exercise, in 12/24 TLC was greater than 80% predicted and in 6/18 lung distensibility was normal. Tl and the change of SaO2 with work output during exercise were highly correlated (r = -0.65, p less than 0.001). In serial studies, the change of SaO2 with work output altered most with clinical improvement or deterioration. The clinical course and response to treatment was not related to a particular pattern of abnormal function. These results and those of previous studies indicate that in DILD the most sensitive index of abnormal parenchymal function is Tl, that lung volumes and distensibility may be normal so that the term "restrictive lung disease" can be misleading, that the fall of SaO2 with work output and Tl are the most sensitive parameters for assessing severity and following the course of the disease and that lung function alone does not predict outcome.

Genetically determined abnormalities of microsomal enzymes in liver of mutant newborn mice

Newborn mice with a lethal mutation at the albino locus have been previously shown to have morphological abnormalities of liver endoplasmic reticulum. These structural defects appear to be accompanied by abnormalities in hepatic microsomal functions. Cyt P-450, and bilirubin glucuronyltransferase activity could not be detected in affected homozygous newborns. Heterozygous and normal homozygous newborns had similar activities, which increased during development to comparable values in adult mice. In contrast, p -nitrophenol glucuronyltransferase activity in affected homozygous mice was fully developed at birth, whereas in heterozygous and normal newborns, p -nitrophenol glucuronyltransferase gradually developed to adult activity. These inherited abnormal functional patterns in homozygous mice with disordered liver SER, and absence of genetic dosage effects in heterozygotes, provide evidence for the possibility that structure-function relationships in endoplasmic membranes are genetically controlled.

Radiologic Evaluation of the Function of the Cervical Spine

Cervical functional examinations initiated in 1965 suggested the need of a correlated, multifactorial expression of the cervical sagittal movement function, allowing comparative evaluations of physiologic-diagnostic significance. Technical aspects of the successive steps of investigation, together with the final morphologic-functional formula are described. The significance of the normal and abnormal functional patterns, identified in a selected series of 300 cases, is finally discussed.