Beyond acute social stress: increased functional connectivity between amygdala and cortical midline structures.

Whereas we know a fair amount on the role of the amygdala in the acute stress response, virtually nothing is known about its role during the recovery period after the stress has waned. Functional connectivity analysis of the amygdala during this period might be useful in revealing brain circuits promoting adaptive recovery from a stressful event, as well as consolidation of emotionally relevant information in preparing for future challenges. Healthy participants were randomly assigned to either a psychosocial stress task (n=18; stress group) or a comparable non-stressful control procedure (n=20; controls).

Electromyographic activity in the EEG in Alzheimer's disease: noise or signal?

Many efforts have been directed at negating the influence of electromyographic (EMG) activity on the EEG, especially in elderly demented patients. We wondered whether these "artifacts" might reflect cognitive and behavioural aspects of dementia. In this pilot study, 11 patients with probable Alzheimer's disease (AD), 13 with amnestic mild cognitive impairment (MCI) and 13 controls underwent EEG registration.

Increased amygdalar and hippocampal volumes in elderly obese individuals with or at risk of cardiovascular disease.

Background: The basal ganglia, hippocampus, and thalamus are involved in the regulation of human feeding behavior. Recent studies have shown that obesity [body mass index (BMI; in kg/m(2)) > 30] is associated with loss of gray and white matter.

Objective: It is unknown whether the subcortical brain structures that are actually involved in feeding behavior also show volume changes in obesity.

Effects of morphine and alcohol on functional brain connectivity during "resting state": a placebo-controlled crossover study in healthy young men.

A major challenge in central nervous system (CNS) drug research is to develop a generally applicable methodology for repeated measurements of drug effects on the entire CNS, without task-related interactions and a priori models. For this reason, data-driven resting-state fMRI methods are promising for pharmacological research. This study aimed to investigate whether different psychoactive substances cause drug-specific effects in functional brain connectivity during resting-state.

Non-parametric model selection for subject-specific topological organization of resting-state functional connectivity.

In recent years, graph theory has been successfully applied to study functional and anatomical connectivity networks in the human brain. Most of these networks have shown small-world topological characteristics: high efficiency in long distance communication between nodes, combined with highly interconnected local clusters of nodes. Moreover, functional studies performed at high resolutions have presented convincing evidence that resting-state functional connectivity networks exhibits (exponentially truncated) scale-free behavior.

MRI artifacts in human brain tissue after prolonged formalin storage.

For the interpretation of magnetic resonance imaging (MRI) abnormalities in brain pathology, often ex vivo tissue is used. The purpose of this study was to determine the pathological substrate of several distinct forms of MR hypointensities that were found in formalin-fixed brain tissue with amyloid-beta deposits. Samples of brain cortex were scanned using effective transverse relaxation time-weighted protocols at several resolutions on a 9.

Early changes in white matter pathways of the sensorimotor cortex in premanifest Huntington's disease.

Objectives: To investigate the function-structure relationship of white matter within different stages of Huntington's disease (HD) using diffusion tensor imaging (DTI).

Experimental Design: From the TRACK-HD study, an early stage HD group and a premanifest gene carrier group (PMGC) were age-matched to two healthy control groups; all underwent 3-T MRI scanning of the brain. Region of interest (ROI) segmentation of the corpus callosum, caudate nucleus, thalamus, prefrontal cortex, and sensorimotor cortex was applied, and the apparent fiber pathways of these regions were analyzed.

New criterion to aid manual and automatic selection of the arterial input function in dynamic susceptibility contrast MRI.

Dynamic susceptibility contrast-MRI requires an arterial input function (AIF) to obtain cerebral blood flow, cerebral blood volume, and mean transit time. The current AIF selection criteria discriminate venous, capillary, and arterial profiles based on shape and timing characteristics of the first passage. Unfortunately, partial volume effects can lead to shape errors in the bolus passage, including a narrower and higher peak, which might be selected as a "correct" AIF.

Pseudocontinuous arterial spin labeling reveals dissociable effects of morphine and alcohol on regional cerebral blood flow.

We have examined sensitivity and specificity of pseudocontinuous arterial spin labeling (PCASL) to detect global and regional changes in cerebral blood flow (CBF) in response to two different psychoactive drugs. We tested alcohol and morphine in a placebo-controlled, double-blind randomized study in 12 healthy young men. Drugs were administered intravenously.

Cerebral microbleeds are predictive of mortality in the elderly.

Background And Purpose: To investigate the prognostic value of cerebral microbleeds (CMB) regarding overall, cardiovascular-related, and stroke-related mortality and to investigate possible differences based on a cerebral amyloid angiopathy-type and nonlobar distribution of microbleeds.

Methods: We included 435 subjects who were participants from the nested MRI substudy of the PROspective Study of Pravastatin in the Elderly at Risk (PROSPER). Cox proportional hazard models were applied to estimate the risk of overall, cardiovascular-related, and stroke-related death associated with microbleeds in general and microbleeds with a lobar distribution suggestive of the presence of cerebral amyloid angiopathy.

Cerebral perfusion and aortic stiffness are independent predictors of white matter brain atrophy in type 1 diabetic patients assessed with magnetic resonance imaging.

Objective: To identify vascular mechanisms of brain atrophy in type 1 diabetes mellitus (DM) patients by investigating the relationship between brain volumes and cerebral perfusion and aortic stiffness using magnetic resonance imaging (MRI).

Research Design And Methods: Approval from the local institutional review board was obtained, and patients gave informed consent. Fifty-one type 1 DM patients (30 men; mean age 44 ± 11 years; mean DM duration 23 ± 12 years) and 34 age- and sex-matched healthy control subjects were prospectively enrolled.

Lenticulostriate arterial lumina are normal in cerebral autosomal-dominant arteriopathy with subcortical infarcts and leukoencephalopathy: a high-field in vivo MRI study.

Background And Purpose: Cerebral autosomal-dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a hereditary small vessel disease. Although postmortem studies have demonstrated mural thickening in leptomeningeal arteries and lenticulostriate perforating arteries, it is unclear whether this also leads to luminal narrowing. High-field MRI scanners enable in vivo imaging of the lumen of the lenticulostriate arteries.

High-field MRI of single histological slices using an inductively coupled, self-resonant microcoil: application to ex vivo samples of patients with Alzheimer's disease.

A simple inductively coupled microcoil has been designed to image tissue samples placed on a microscope slide, samples which can subsequently be stained histologically. As the exact same tissue is used for MRI and histology, the two data sets can be compared without the need for complicated image registration techniques. The design can be integrated into any MRI system using existing commercial hardware.

Whole brain resting-state analysis reveals decreased functional connectivity in major depression.

Recently, both increases and decreases in resting-state functional connectivity have been found in major depression. However, these studies only assessed functional connectivity within a specific network or between a few regions of interest, while comorbidity and use of medication was not always controlled for. Therefore, the aim of the current study was to investigate whole-brain functional connectivity, unbiased by a priori definition of regions or networks of interest, in medication-free depressive patients without comorbidity.

Early atrophy of pallidum and accumbens nucleus in Huntington's disease.

In Huntington's disease (HD) atrophy of the caudate nucleus and putamen has been described many years before clinical manifestation. Volume changes of the pallidum, thalamus, brainstem, accumbens nucleus, hippocampus, and amygdala are less well investigated, or reported with contradicting results. The aim of our study is to provide a more precise view of the specific atrophy of the subcortical grey matter structures in different stages of Huntington's disease, and secondly to investigate how this influences the clinical manifestations.

Shape abnormalities of the striatum in Alzheimer's disease.

Postmortem studies show pathological changes in the striatum in Alzheimer's disease (AD). Here, we examine the surface of the striatum in AD and assess whether changes of the surface are associated with impaired cognitive functioning. The shape of the striatum (n.

Regional brain volume in depression and anxiety disorders.

Context: Major depressive disorder (MDD), panic disorder, and social anxiety disorder are among the most prevalent and frequently co-occurring psychiatric disorders in adults and may have, at least in part, a common etiology.

Objective: To identify the unique and shared neuroanatomical profile of depression and anxiety, controlling for illness severity, medication use, sex, age of onset, and recurrence.

Design: Cross-sectional study.

Tractography of developing white matter of the internal capsule and corpus callosum in very preterm infants.

Objectives: To investigate in preterm infants associations between Diffusion Tensor Imaging (DTI) parameters of the posterior limb of the internal capsule (PLIC) and corpus callosum (CC) and age, white matter (WM) injury and clinical factors.

Methods: In 84 preterm infants DTI was performed between 40-62 weeks postmenstrual age on 3 T MR. Fractional anisotropy (FA), apparent diffusion coefficient (ADC) values and fibre lengths through the PLIC and the genu and splenium were determined.

Tract-based spatial statistics on diffusion tensor imaging in systemic lupus erythematosus reveals localized involvement of white matter tracts.

Objective: The aim of this study was to determine whether there are differences in white matter integrity between systemic lupus erythematosus (SLE) patients and healthy controls, as determined using tract-based spatial statistics (TBSS) analysis of diffusion tensor imaging data.

Methods: Twelve patients with SLE (mean age 42 years [range 15-61 years]) diagnosed according to the American College of Rheumatology 1982 revised criteria for SLE and 28 healthy controls (mean age 46 years [range 21-61 years]) were included in the study. Magnetic resonance imaging was performed on a 3.

Reduced medial prefrontal cortex volume in adults reporting childhood emotional maltreatment.

Background: Childhood emotional maltreatment (CEM) has been associated with a profound and enduring negative impact on behavioral and emotional functioning. Animal models have shown that adverse rearing conditions, such as maternal separation, can induce a cascade of long-term structural alterations in the brain, particularly in the hippocampus, amygdala, and prefrontal cortex. However, in humans, the neurobiological correlates of CEM are unknown.

Perfusion MRI in neuro-psychiatric systemic lupus erthemathosus.

Purpose: To use perfusion weighted MR to quantify any perfusion abnormalities and to determine their contribution to neuropsychiatric (NP) involvement in systemic lupus erythematosus (SLE).

Materials And Methods: We applied dynamic susceptibility contrast (DSC) perfusion MRI in 15 active NPSLE, 26 inactive NPSLE patients, and 11 control subjects. Cerebral blood flow (CBF), cerebral blood volume (CBV), and mean transit time (MTT) maps were reconstructed and regions of interest were compared between groups.

Phase-based arterial input function measurements for dynamic susceptibility contrast MRI.

In dynamic susceptibility contrast perfusion MRI, arterial input function (AIF) measurements using the phase of the MR signal are traditionally performed inside an artery. However, phase-based AIF selection is also feasible in tissue surrounding an artery such as the middle cerebral artery, which runs approximately perpendicular to B(0) since contrast agents also induce local field changes in tissue surrounding the artery. The aim of this study was to investigate whether phase-based AIF selection is better performed in tissue just outside the middle cerebral artery than inside the artery.

A comprehensive study of whole-brain functional connectivity in children and young adults.

Over the past decade, examination of functional connectivity using functional magnetic resonance imaging has become an important tool to investigate functional changes in patient populations, healthy aging, and recently also child development. Most prior developmental studies focused on functional connectivity between brain regions important for cognitive or emotional control and the so-called "default-mode network." In the present study, we investigated whole-brain functional connectivity in children (11-13 years; N = 19) and young adults (19-25 years; N = 29), without a priori restrictions to specific regions.

Practice effects in the brain: Changes in cerebral activation after working memory practice depend on task demands.

Several studies have examined the neural effects of working memory practice, but due to different task demands, diverse patterns of neural changes have been reported. In the present study, we examined neural effects of practice using a task with different working memory demands within a single practice paradigm. Fifteen adults practiced during 6weeks with a task that required maintenance and manipulation of information under low and high working memory loads.

Coronary artery calcium, brain function and structure: the AGES-Reykjavik Study.

Background And Purpose: Several cardiovascular risk factors are associated with cognitive disorders in older persons. Little is known about the association of the burden of coronary atherosclerosis with brain structure and function.

Methods: This is a cross-sectional analysis of data from the Age, Gene, Environment Susceptibility (AGES)-Reykjavik Study cohort of men and women born 1907 to 1935.