Mental fatigue correlates with depression of task-related network and augmented DMN activity but spares the reward circuit.

Long-lasting and demanding cognitive activity typically leads to mental fatigue (MF). Indirect evidence suggests that MF may be caused by altered motivational processes. Here, we hypothesized that if MF consists in an alteration of motivational states, brain functional changes induced by MF could specifically affect the brain motivation circuit.

Effect of Distracting Background Speech in an Auditory Brain-Computer Interface.

Studies so far have analyzed the effect of distractor stimuli in different types of brain-computer interface (BCI). However, the effect of a background speech has not been studied using an auditory event-related potential (ERP-BCI), a convenient option when the visual path cannot be adopted by users. Thus, the aim of the present work is to examine the impact of a background speech on selection performance and user workload in auditory BCI systems.

Insomnia does not affect heart rate changes when young adults watch humorous films: An exploratory study.

Emotional reactivity in insomnia is affected both subjectively and on a physiological level for negative emotional material, but little is known about reactions to positive stimuli. We here investigated whether in younger adult insomnia patients, presentation of short humorous films would lead to heart rate decreases during and after film viewing, as compared to heart rate changes when falling asleep. Investigating 20 participants with DSM-5-diagnosed insomnia and 18 participants without insomnia, we found that heart rate decreased when falling asleep, increased when watching humorous films and returned to normal values afterwards for all participants.

Application of Machine Learning to Arterial Spin Labeling in Mild Cognitive Impairment and Alzheimer Disease.

Purpose To investigate whether multivariate pattern recognition analysis of arterial spin labeling (ASL) perfusion maps can be used for classification and single-subject prediction of patients with Alzheimer disease (AD) and mild cognitive impairment (MCI) and subjects with subjective cognitive decline (SCD) after using the W score method to remove confounding effects of sex and age. Materials and Methods Pseudocontinuous 3.0-T ASL images were acquired in 100 patients with probable AD; 60 patients with MCI, of whom 12 remained stable, 12 were converted to a diagnosis of AD, and 36 had no follow-up; 100 subjects with SCD; and 26 healthy control subjects.

Impact of APOE-ɛ4 and family history of dementia on gray matter atrophy in cognitively healthy middle-aged adults.

The apolipoprotein E ε4 allele (APOE4) and family history of dementia (FH) are well-known risk factors for the development of sporadic Alzheimer's disease. We assessed the effects of these risk factors on gray matter (GM) volume in 295 cognitively healthy middle-aged community-dwelling subjects. Voxel-based morphometry was used to study GM volume differences between high- and low-risk subjects, based on APOE4 carriership (n = 74), first-degree FH (n = 228), or both (n = 62).

Information Flow Between Resting-State Networks.

Unlabelled: The resting brain dynamics self-organize into a finite number of correlated patterns known as resting-state networks (RSNs). It is well known that techniques such as independent component analysis can separate the brain activity at rest to provide such RSNs, but the specific pattern of interaction between RSNs is not yet fully understood. To this aim, we propose here a novel method to compute the information flow (IF) between different RSNs from resting-state magnetic resonance imaging.

Reading networks in children with dyslexia compared to children with ocular motility disturbances revealed by fMRI.

Key PointsDyslexia is a neurological disorder with a genetic origin, but the underlying biological and cognitive causes are still being investigated.This study compares the brain activation pattern while reading in Spanish, a semitransparent language, in three groups of children: typically developing readers, dyslexic readers and readers with functional monocular vision.Based on our results Dyslexia would be a neurological disorder not related to vision impairments and would require a multidisciplinary treatment based on improving phonological awareness and language development.

The caudate: a key node in the neuronal network imbalance of insomnia?

Insomnia is prevalent, severe and partially heritable. Unfortunately, its neuronal correlates remain enigmatic, hampering the development of mechanistic models and rational treatments. Consistently reported impairments concern fragmented sleep, hyper-arousal and executive dysfunction.

Amyloid and its association with default network integrity in Alzheimer's disease.

The purpose of this study was to investigate the association between functional connectivity and β-amyloid depositions in the default mode network (DMN) in Alzheimer's disease (AD), patients with mild cognitive impairment (MCI), and healthy elderly. Twenty-five patients with AD, 12 patients with MCI, and 18 healthy controls were included in the study. Resting-state functional magnetic resonance imaging was used to assess functional connectivity in the DMN.

Functional segmentation of the hippocampus in the healthy human brain and in Alzheimer's disease.

In this study we segment the hippocampus according to functional connectivity assessed from resting state functional magnetic resonance images in healthy subjects and in patients with Alzheimer's disease (AD). We recorded the resting FMRI signal from 16 patients and 22 controls. We used seed-based functional correlation analyses to calculate partial correlations of all voxels in the hippocampus relative to characteristic regional signal changes in the thalamus, the prefrontal cortex (PFC) and the posterior cingulate cortex (PCC), while controlling for ventricular CSF and white matter signals.

Resting-state brain networks in type 1 diabetic patients with and without microangiopathy and their relation to cognitive functions and disease variables.

Cognitive functioning depends on intact brain networks that can be assessed with functional magnetic resonance imaging (fMRI) techniques. We hypothesized that cognitive decrements in type 1 diabetes mellitus (T1DM) are associated with alterations in resting-state neural connectivity and that these changes vary according to the degree of microangiopathy. T1DM patients with (MA(+): n = 49) and without (MA(-): n = 52) microangiopathy were compared with 48 healthy control subjects.

Gender-related differences in functional connectivity in multiple sclerosis.

Background: Gender effects are strong in multiple sclerosis (MS), with male patients showing a worse clinical outcome than female patients. Functional reorganization of neural activity may contribute to limit disability, and possible gender differences in this process may have important clinical implications.

Objectives: The aim of this study was to explore gender-related changes in functional connectivity and network efficiency in MS patients.

Resting-state networks in awake five- to eight-year old children.

During the first 6-7 years of life children undergo a period of major neurocognitive development. Higher-order cognitive functions such as executive control of attention, encoding and retrieving of stored information and goal-directed behavior are present but less developed compared to older individuals. There is only very limited information from functional magnetic resonance imaging (fMRI) studies about the level of organization of functional networks in children in the early school period.

Loss of 'small-world' networks in Alzheimer's disease: graph analysis of FMRI resting-state functional connectivity.

Background: Local network connectivity disruptions in Alzheimer's disease patients have been found using graph analysis in BOLD fMRI. Other studies using MEG and cortical thickness measures, however, show more global long distance connectivity changes, both in functional and structural imaging data. The form and role of functional connectivity changes thus remains ambiguous.

Modulating spontaneous brain activity using repetitive transcranial magnetic stimulation.

Background: When no specific stimulus or task is presented, spontaneous fluctuations in brain activity occur. Brain regions showing such coherent fluctuations are thought to form organized networks known as 'resting-state' networks, a main representation of which is the default mode network. Spontaneous brain activity shows abnormalities in several neurological and psychiatric diseases that may reflect disturbances of ongoing thought processes.

3-D cytoarchitectonic parcellation of human orbitofrontal cortex correlation with postmortem MRI.

The orbitofrontal cortex (OFC) is located on the basal surface of the frontal lobe and is distinguished by its unique anatomical and functional features. Clinical and postmortem studies suggest the involvement of the orbitofrontal cortex in psychiatric disorders. However, the exact parcellation of this cortical region is still a matter of debate.

Resting state networks change in clinically isolated syndrome.

Task-functional magnetic resonance imaging studies have shown that early cortical recruitment exists in multiple sclerosis, which can partly explain the discrepancy between conventional magnetic resonance imaging and clinical disability. The study of the brain 'at rest' may provide additional information, because task-induced metabolic changes are relatively small compared to the energy use of the resting brain. We therefore questioned whether functional changes exist at rest in the early phase of multiple sclerosis, and addressed this question by a network analysis of no-task functional magnetic resonance imaging data.

Sleep benefits subsequent hippocampal functioning.

Sleep before learning benefits memory encoding through unknown mechanisms. We found that even a mild sleep disruption that suppressed slow-wave activity and induced shallow sleep, but did not reduce total sleep time, was sufficient to affect subsequent successful encoding-related hippocampal activation and memory performance in healthy human subjects. Implicit learning was not affected.

Prefrontal hypoactivation and recovery in insomnia.

Study Objectives: Although subjective complaints about daytime cognitive functioning are an essential symptom of chronic insomnia, abnormalities in functional brain activation have not previously been investigated. This study was designed to investigate functional brain activation differences as a possible result of chronic insomnia, and the reversibility of these differences after nonmedicated sleep therapy.

Design: Insomniacs and carefully matched controls underwent functional magnetic resonance imaging (fMRI) scanning during the performance of a category and a letter fluency task.

White matter tract integrity in aging and Alzheimer's disease.

The pattern of degenerative changes in the brain white matter (WM) in aging, mild cognitive impairment (MCI), and Alzheimer's disease (AD) has been under debate. Methods of image analysis are an important factor affecting the outcomes of various studies. Here we used diffusion tensor imaging (DTI) to obtain fractional anisotropy (FA) measures of the WM in healthy young (n = 8), healthy elderly (n = 22), MCI (n = 8), and AD patients (n = 16).

Regional frontal cortical volumes decrease differentially in aging: an MRI study to compare volumetric approaches and voxel-based morphometry.

Recent neuroimaging studies suggest that the frontal lobes are the part of the brain most profoundly affected by the aging process. The present study investigated whether subregions within the frontal cortex show different patterns of brain aging. Magnetic resonance images of 57 healthy participants between 21 and 81 years old were used to measure regional frontal gray matter volumes in three ways: a manual tracing method, a semiautomatic "Talairach boxes" volumetric method, and voxel-based morphometry.