Connectivity of default-mode network is associated with cerebral edema in hepatic encephalopathy.

Cerebral edema, a well-known feature of acute liver disease, can occur in cirrhotic patients regardless of hepatic encephalopathy (HE) and adversely affect prognosis. This study characterized and correlated functional HE abnormalities in the brain to cerebral edema using resting-state functional magnetic resonance imaging (rs-fMRI) and diffusion tensor imaging (DTI). Forty-one cirrhotic patients (16 without HE, 14 minimal HE, 11 overt HE) and 32 healthy controls were assessed.

Impaired small-world network efficiency and dynamic functional distribution in patients with cirrhosis.

Hepatic encephalopathy (HE) is a complex neuropsychiatric syndrome and a major complication of liver cirrhosis. Dysmetabolism of the brain, related to elevated ammonia levels, interferes with intercortical connectivity and cognitive function. For evaluation of network efficiency, a 'small-world' network model can quantify the effectiveness of information transfer within brain networks.

White matter abnormalities correlating with memory and depression in heroin users under methadone maintenance treatment.

Methadone maintenance treatment (MMT) has elevated rates of co-morbid memory deficit and depression that are associated with higher relapse rates for substance abuse. White matter (WM) disruption in MMT patients have been reported but their impact on these co-morbidities is unknown. This study aimed to investigate changes in WM integrity of MMT subjects using diffusion tensor image (DTI), and their relationship with history of heroin and methadone use in treated opiate-dependent individuals.

Multiple diffusivities define white matter degeneration in amnestic mild cognitive impairment and Alzheimer's disease.

Different diffusivity measurements in diffusion-tensor imaging (DTI) could be helpful for detecting the distinct mechanisms of white matter degeneration in Alzheimer's disease (AD). However, few studies have explored the changes of white matter in amnestic mild cognitive impairment (aMCI) and AD by whole-brain voxel-wise analyses of all diffusivity indices. The association between grey matter atrophy and white matter damage measured by distinct diffusivities is still uncertain.

Structural deficits in the emotion circuit and cerebellum are associated with depression, anxiety and cognitive dysfunction in methadone maintenance patients: a voxel-based morphometric study.

Heroin users on methadone maintenance treatment (MMT) have elevated rates of co-morbid depression and are associated with have higher relapse rates for substance abuse. Structural abnormalities in MMT patients have been reported, but their impact on clinical performance is unknown. We investigated differences in gray matter volume (GMV) between 27 MMT patients and 23 healthy controls with voxel-based morphometry, and we correlated findings in the patients with Beck Depression Inventory scores, Beck Anxiety Inventory scores, and diminished cognitive functioning.

Effect of Bcl-2 rs956572 SNP on regional gray matter volumes and cognitive function in elderly males without dementia.

The Bcl-2 gene is a major regulator of neural plasticity and cellular resilience. A single-nucleotide polymorphism (SNP) in the Bcl-2 gene, Bcl-2 rs956572, significantly modulates the expression of Bcl-2 protein and cellular vulnerability to apoptosis. This study investigated the association between the Bcl-2 rs956572 SNP and brain structural abnormalities in non-demented elders, and to test the relationship between neuropsychological performance and regional gray matter (GM) volumes.

Does feature selection improve classification accuracy? Impact of sample size and feature selection on classification using anatomical magnetic resonance images.

There are growing numbers of studies using machine learning approaches to characterize patterns of anatomical difference discernible from neuroimaging data. The high-dimensionality of image data often raises a concern that feature selection is needed to obtain optimal accuracy. Among previous studies, mostly using fixed sample sizes, some show greater predictive accuracies with feature selection, whereas others do not.

Voxel-based analysis of apparent diffusion coefficient in perihaematomal oedema: associated factors and outcome predictive value for intracerebral haemorrhage.

Objectives The pathophysiology of perihaematomal oedema (PO) surrounding a primary intracerebral haemorrhage (ICH) is complicated and incompletely understood. We prospectively investigated the components of PO with voxel-based analysis of the apparent diffusion coefficient (ADC) value and assessed its predictive value for functional outcome. Design Forty-six patients with ICH who were enrolled for clinical evaluation underwent MRI scans within 24 h after ICH.

Anatomical insights into disrupted small-world networks in schizophrenia.

Schizophrenia is characterized by lowered efficiency in distributed information processing, as indicated by research that identified a disrupted small-world functional network. However, whether the dysconnection manifested by the disrupted small-world functional network is reflected in underlying anatomical disruption in schizophrenia remains unresolved. This study examined the topological properties of human brain anatomical networks derived from diffusion tensor imaging in patients with schizophrenia and in healthy controls.

Associations between Circle of Willis morphology and white matter lesion load in subjects with carotid artery stenosis.

Background: Various cerebral pathological changes have been reported to cause leukoaraiosis (LA). We hypothesized that circle of Willis (CoW) anomalies may contribute to LA in severe carotid artery stenosis victims through impaired cerebral autoregulation. We conducted a retrospective review on cerebral magnetic resonance (MR) patterns in patients with severe symptomatic carotid artery stenosis and compared white matter lesion (WML) load between subjects with and without complete CoW.

Graph theoretical analysis of human brain structural networks.

There is a growing interest in exploring the connectivity patterns of the human brain. Specifically, the utility of noninvasive neuroimaging data and graph theoretical analysis have provided important insights into the anatomical connections and topological pattern of human brain structural networks in vivo. This review focuses on recent methodological and application studies, utilizing graph theoretical approaches, on brain structural networks with structural magnetic resonance imaging (MRI) and diffusion MRI.

Differences in early dynamic connectivity between visual expansion and contraction stimulations revealed by an fMRI-directed MEG approach.

Background And Purpose: The human visual system responds asymmetrically to visual motion stimuli in opposite directions due to the involvement of the same brain areas but different operating processes. The expansion mode is thought to invoke a vigilance mechanism, whereas the contraction mode does not.

Methods: To investigate discrepancies between these modes, we produced dynamic connectivity maps based on mutual information between visual-evoked dipole sources of magnetoencephalography, which were steered by visual activity patterns in functional magnetic resonance imaging under two motion-stimulus modes.

ANS: aberrant neurodevelopment of the social cognition network in adolescents with autism spectrum disorders.

Background: Autism spectrum disorders (ASD) are characterized by aberrant neurodevelopment. Although the ASD brain undergoes precocious growth followed by decelerated maturation during early postnatal period of childhood, the neuroimaging approach has not been empirically applied to investigate how the ASD brain develops during adolescence.

Methodology/principal Findings: We enrolled 25 male adolescents with high functioning ASD and 25 typically developing controls for voxel-based morphometric analysis of structural magnetic resonance image.

The prevalence of dementia and depression in Taiwanese institutionalized leprosy patients, and the effectiveness evaluation of reminiscence therapy--a longitudinal, single-blind, randomized control study.

Objective: This study investigated the prevalence of depression and dementia in long-term institutionalized older leprosy patients in Taiwan. We then examined the effectiveness of reminiscence group therapy on depressive symptoms and cognitive function in this population.

Methods: We recruited 129 long-term institutionalized older leprosy patients in Taiwan and used the Geriatric Depression Scale-Short Form (GDS-SF), the mini mental state examination (MMSE), and the Clinical Dementia Rating (CDR) scale for outcome measurement.

Empirical evaluations of slice-timing, smoothing, and normalization effects in seed-based, resting-state functional magnetic resonance imaging analyses.

Recently, functional connectivity analyses using spontaneous functional magnetic resonance imaging (fMRI) fluctuations have been applied in the context of neurological and psychiatry diseases. In the analyses procedure, preprocessing steps are commonly utilized in exploring functional connectivity, the same strategy as what was conducted in the fMRI process. However, the effectiveness of these preprocessing steps on resting-state fMRI (rs-fMRI) was rarely investigated, and the significance of preprocessing steps on rs-fMRI needs to be studied.

Diffusion tensor tractography reveals abnormal topological organization in structural cortical networks in Alzheimer's disease.

Recent research on Alzheimer's disease (AD) has shown that the decline of cognitive and memory functions is accompanied by a disrupted neuronal connectivity characterized by white matter (WM) degeneration. However, changes in the topological organization of WM structural network in AD remain largely unknown. Here, we used diffusion tensor image tractography to construct the human brain WM networks of 25 AD patients and 30 age- and sex-matched healthy controls, followed by a graph theoretical analysis.

Persistent ictal-like visual cortical excitability in chronic migraine.

Episodic migraine (EM) may evolve into the more disabling chronic migraine (CM, monthly migraine days ≥ 8 and headache days ≥ 15) with unknown mechanism. Aiming to elucidate the pathophysiology of CM and its relationship with EM, this study characterized the visual cortical responses in CM and EM. Neuromagnetic visual-evoked responses to left-hemifield checkerboard reversals were obtained in patients with EM (interictal or ictal states), CM (interictal) and age-matched controls.

Diffeomorphic image registration of diffusion MRI using spherical harmonics.

Nonrigid registration of diffusion magnetic resonance imaging (MRI) is crucial for group analyses and building white matter and fiber tract atlases. Most current diffusion MRI registration techniques are limited to the alignment of diffusion tensor imaging (DTI) data. We propose a novel diffeomorphic registration method for high angular resolution diffusion images by mapping their orientation distribution functions (ODFs).

Use of diffusion tensor imaging to identify similarities and differences between cerebellar and Parkinsonism forms of multiple system atrophy.

Introduction: We performed diffusion tensor imaging to determine if multiple system atrophy (MSA)-cerebellar (C) and MSA-Parkinsonism (P) show similar changes, as shown in pathological studies.

Methods: Nineteen patients with MSA-C, 12 patients with MSA-P, 20 patients with Parkinson disease, and 20 healthy controls were evaluated with the use of voxel-based morphometry analysis of diffusion tensor imaging.

Results: There was an increase in apparent diffusion coefficient values in the middle cerebellar peduncles and cerebellum and a decrease in fractional anisotropy in the pyramidal tract, middle cerebellar peduncles, and white matter of the cerebellum in patients with MSA-C and MSA-P compared to the controls (P < 0.

Elevated expression of TDP-43 in the forebrain of mice is sufficient to cause neurological and pathological phenotypes mimicking FTLD-U.

TDP-43 is a multifunctional DNA/RNA-binding factor that has been implicated in the regulation of neuronal plasticity. TDP-43 has also been identified as the major constituent of the neuronal cytoplasmic inclusions (NCIs) that are characteristic of a range of neurodegenerative diseases, including the frontotemporal lobar degeneration with ubiquitin(+) inclusions (FTLD-U) and amyotrophic lateral sclerosis (ALS). We have generated a FTLD-U mouse model (CaMKII-TDP-43 Tg) in which TDP-43 is transgenically overexpressed in the forebrain resulting in phenotypic characteristics mimicking those of FTLD-U.

Sex-linked white matter microstructure of the social and analytic brain.

Sexual dimorphism in the brain is known to underpin sex differences in neuropsychological behaviors. The white matter (WM) microstructure appears to be coupled with cognitive performances. However, the issues concerning sex differences in WM remains to be determined.

Appraising the plasticity of the circle of Willis: a model of hemodynamic modulation in cerebral arteriovenous malformations.

Objectives: Cerebral arteriovenous malformations (AVMs) harbor a network of abnormal vasculatures, namely the nidus between arterial and venous components. The pressure gradient between these two components results in abnormal high-velocity arteriovenous shunts flowing through the nidus and alternate intracranial hemodynamics. This study hypothesizes that the flow patterns of the circle of Willis (CoW) are modulated by the alternation of intracranial hemodynamics occurring in cerebral AVMs.

The effect of finite diffusion gradient pulse duration on fibre orientation estimation in diffusion MRI.

An essential step for fibre-tracking is the accurate estimation of neuronal fibre orientations within each imaging voxel, and a number of methods have been proposed to reconstruct the orientation distribution function based on sampling three-dimensional q-space. In the q-space formalism, very short (infinitesimal) gradient pulses are the basic requirement to obtain the true spin displacement probability density function. On current clinical MR systems however, the diffusion gradient pulse duration (delta) is inevitably finite due to the limit on the achievable gradient intensity.

Love hurts: an fMRI study.

Being in a close relationship is essential to human existence. Such closeness can be described as including other in the self and be underpinned on social attachment system, which evolved from a redirection of nociceptive mechanisms. To what extent does imagining a loved-one differs from imagining an unfamiliar individual being in painful situations? In this functional MRI study, participants were exposed to animated stimuli depicting hands or feet in painful and non-painful situations, and instructed to imagine these scenarios from three different perspectives: self, loved-one and stranger after being primed with their respective photographs.

Toward discovery science of human brain function.

Although it is being successfully implemented for exploration of the genome, discovery science has eluded the functional neuroimaging community. The core challenge remains the development of common paradigms for interrogating the myriad functional systems in the brain without the constraints of a priori hypotheses. Resting-state functional MRI (R-fMRI) constitutes a candidate approach capable of addressing this challenge.