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functional fMRI

Matthias Stangl, Johannes Achtzehn, Karin Huber, Caroline Dietrich, Claus Tempelmann, Thomas Wolbers
A progressive loss of navigational abilities in old age has been observed in numerous studies, but we have only limited understanding of the neural mechanisms underlying this decline [1]. A central component of the brain's navigation circuit are grid cells in entorhinal cortex [2], largely thought to support intrinsic self-motion-related computations, such as path integration (i.e., keeping track of one's position by integrating self-motion cues) [3-6]. Given that entorhinal cortex is particularly vulnerable to neurodegenerative processes during aging and Alzheimer's disease [7-14], deficits in grid cell function could be a key mechanism to explain age-related navigational decline...
March 12, 2018: Current Biology: CB
Shu-Hsien Chu, Keshab K Parhi, Christophe Lenglet
A joint structural-functional brain network model is presented, which enables the discovery of function-specific brain circuits, and recovers structural connections that are under-estimated by diffusion MRI (dMRI). Incorporating information from functional MRI (fMRI) into diffusion MRI to estimate brain circuits is a challenging task. Usually, seed regions for tractography are selected from fMRI activation maps to extract the white matter pathways of interest. The proposed method jointly analyzes whole brain dMRI and fMRI data, allowing the estimation of complete function-specific structural networks instead of interactively investigating the connectivity of individual cortical/sub-cortical areas...
March 16, 2018: Scientific Reports
Maryam Falahpour, Catie Chang, Chi Wah Wong, Thomas T Liu
Changes in vigilance or alertness during a typical resting state fMRI scan are inevitable and have been found to affect measures of functional brain connectivity. Since it is not often feasible to monitor vigilance with EEG during fMRI scans, it would be of great value to have methods for estimating vigilance levels from fMRI data alone. A recent study, conducted in macaque monkeys, proposed a template-based approach for fMRI-based estimation of vigilance fluctuations. Here, we use simultaneously acquired EEG/fMRI data to investigate whether the same template-based approach can be employed to estimate vigilance fluctuations of awake humans across different resting-state conditions...
March 13, 2018: NeuroImage
Liang Shi, Jiangzhou Sun, Zhiting Ren, Qunlin Chen, Dongtao Wei, Wenjing Yang, Jiang Qiu
Creativity is imperative to social development and the promotion of well-being. Here, independent component analysis and functional network connectivity analysis methods were applied to both resting-state and divergent thinking task fMRI data from the same sample to investigate large-scale brain network connectivity underlying creativity. The results showed that the strength of the connectivity between the posterior default mode network (DMN) and right frontal-parietal network (FPN) was significantly greater whereas the right FPN and left FPN connectivity strength was weaker in the creative condition than in the control condition...
March 13, 2018: Biological Psychology
Frederic von Wegner, Helmut Laufs, Enzo Tagliazucchi
Long-range memory in time series is often quantified by the Hurst exponent H, a measure of the signal's variance across several time scales. We analyze neurophysiological time series from electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) resting state experiments with two standard Hurst exponent estimators and with the time-lagged mutual information function applied to discretized versions of the signals. A confidence interval for the mutual information function is obtained from surrogate Markov processes with equilibrium distribution and transition matrix identical to the underlying signal...
February 2018: Physical Review. E
Ashley A Yttredahl, Erin McRobert, Benjamin Sheler, Brian J Mickey, Tiffany M Love, Scott A Langenecker, Jon-Kar Zubieta, David T Hsu
INTRODUCTION: Responding adaptively to one's social environment is a key factor predicting the course of major depressive disorder (MDD). Socially rejecting events can exacerbate, whereas socially accepting events can ameliorate depressive symptoms. The neural responses to rejection and acceptance in MDD are relatively unexplored. METHODS: We used functional magnetic resonance imaging (fMRI) to measure neural responses to romantic rejection and acceptance in women diagnosed with current MDD (n = 19) and a matched group of healthy controls (HCs) (n = 19)...
February 27, 2018: Journal of Affective Disorders
Hesham Mostafa Zakaria, Peter Joseph Massa, Richard L Smith, Tarek Hazem Moharram, John Corrigan, Ian Lee, Lonni Schultz, Jianhui Hu, Suresh Patel, Brent Griffith
Preoperative identification of the eloquent brain is important for neurosurgical planning. One common method of finding the motor cortex is by localizing "the Omega sign." No studies have tested the reliability of imaging to identify the Omega sign. We identified 40 recent and consecutive patients who had undergone preoperative functional magnetic resonance imaging for identification of the hand motor area prior to tumor resection. We recruited 11 neurosurgical residents of various levels of training and one board-certified neurosurgeon to identify the hand motor cortex Omega...
January 1, 2018: Neuroradiology Journal
Jiayu Chen, Barnaly Rashid, Qingbao Yu, Jingyu Liu, Dongdong Lin, Yuhui Du, Jing Sui, Vince D Calhoun
Imaging genetics posits a valuable strategy for elucidating genetic influences on brain abnormalities in psychiatric disorders. However, association analysis between 2D genetic data (subject × genetic variable) and 3D first-level functional magnetic resonance imaging (fMRI) data (subject × voxel × time) has been challenging given the asymmetry in data dimension. A summary feature needs to be derived for the imaging modality to compute inter-modality association at subject level. In this work, we propose to use variability in resting state networks (RSNs) and functional network connectivity (FNC) as potential features for purpose of association analysis...
2018: Frontiers in Neuroscience
T Labbé Atenas, E Ciampi Díaz, J P Cruz Quiroga, S Uribe Arancibia, C Cárcamo Rodríguez
Functional magnetic resonance imaging (fMRI) is an advanced tool for the study of brain functions in healthy subjects and in neuropsychiatric patients. This tool makes it possible to identify and locate specific phenomena related to neuronal metabolism and activity. Starting with the detection of changes in the blood supply to a region that participates in a function, more complex approaches have been developed to study the dynamics of neuronal networks. Studies examining the brain at rest or involved in different tasks have provided evidence related to the onset, development, and/or response to treatment in various diseases...
March 12, 2018: Radiología
Qihong Zou, Shuqin Zhou, Jing Xu, Zihui Su, Yuezhen Li, Yundong Ma, Hongqiang Sun, Changwei W Wu, Jia-Hong Gao
Rapid eye movement (REM) sleep has been frequently associated with dreaming. However, mounting evidence obtained from behavioral, pharmacological, and brain imaging studies suggests that REM sleep is not indicative of the dream report and may originate from diverse neural substrates in brain functionality. The aim of the current study was to investigate the functional systems associated with inter-individual differences in dream recall and REM sleep through assessments of the resting-state functional connectivity...
March 12, 2018: NeuroImage
Yoonjin Nah, Na-Young Shin, Sehjung Yi, Seung-Koo Lee, Sanghoon Han
Numerous studies have suggested that postpartum women show a decline in cognitive abilities. However, to date, no study has investigated the presence of qualitative alterations in recognition memory processes in postpartum women that may lead to a decline in cognitive ability. To address this issue, we employed the Remember/Know procedure and functional magnetic resonance imaging (fMRI). Behavioral results demonstrated that compared with the matched control (CTRL) group, the postpartum (PP) group endorsed "Remember" less and "Know" more to old items...
March 12, 2018: Neurobiology of Learning and Memory
Elizabeth A Shay, Quanjing Chen, Frank E Garcea, Bradford Z Mahon
Multivoxel pattern analysis (MVPA) over functional MRI data can distinguish neural representational states that do not differ in their overall amplitude of BOLD contrast. Here we used MVPA to test whether simple intransitive actions can be distinguished in primary motor cortex. Participants rotated and flexed each of their extremities (hands and feet) during fMRI scanning. The primary motor cortex for the hand/wrist was functionally defined in each hemisphere in each subject. Within those subject-specific ROIs, we found that the average amplitude of BOLD contrast for two different movements of the contralateral hand (rotation, flexion) were higher than for the ipsilateral hand, as well as movements by both feet; however, there was no difference in amplitude between the two different types of movements for the contralateral hand...
March 16, 2018: Cognitive Neuroscience
Jeroen Gielen, Wietse Wiels, Jeroen Van Schependom, Jorne Laton, Wim Van Hecke, Paul M Parizel, Marie Beatrice D'hooghe, Guy Nagels
INTRODUCTION: The paced serial addition test (PSAT) is regularly used to assess cognitive deficits in various neuropsychiatric conditions. Being a complex test, it reflects the status of multiple cognitive domains such as working memory, information processing speed and executive functioning. Two versions of the PSAT exist. One uses auditory stimuli through spoken numbers and is known as the PASAT, while the other one presents patients with visual stimuli and is called PVSAT. The PASAT is considered more frustrating by patients, and hence the visual version is usually preferred...
2018: PloS One
Lotte F van Dillen, Henk van Steenbergen
The present research examined whether cognitive load modulates the neural processing of appetitive, high-calorie food stimuli. In a functional magnetic resonance imaging (fMRI) study, participants quickly categorized high-calorie and low-calorie food pictures versus object pictures as edible or inedible while they concurrently performed a digit-span task that varied between low and high cognitive load (memorizing six digits vs. one digit). In line with predictions, the digit-span task engaged the dorsolateral prefrontal cortex (DLPFC) when cognitive load was high compared to low...
March 14, 2018: Cognitive, Affective & Behavioral Neuroscience
Andrew J Lawrence, Daniel J Tozer, Emmanuel A Stamatakis, Hugh S Markus
Objective: MRI measures of network integrity may be useful disease markers in cerebral small vessel disease (SVD). We compared the sensitivity and reproducibility of MRI derived structural and functional network measures in healthy controls and SVD subjects. Methods: Diffusion tractography and resting state fMRI were used to create connectivity matrices from 26 subjects with symptomatic MRI confirmed lacunar stroke and 19 controls. Matrices were constructed at multiple scales based on a multi-resolution cortical atlas and at multiple thresholds for the matrix density...
2018: NeuroImage: Clinical
Derek Kellar, Sharlene Newman, Franco Pestilli, Hu Cheng, Nicholas L Port
Objectives: Though sub-concussive impacts are common during contact sports, there is little consensus whether repeat blows affect brain function. Using a "lifetime exposure" rather than acute exposure approach, we examined oculomotor performance and brain activation among collegiate football players and two control groups. Our analysis examined whether there are group differences in eye movement behavioral performance and in brain activation during smooth pursuit. Methods: Data from 21 off-season Division I football "starters" were compared with a) 19 collegiate cross-country runners, and b) 11 non-athlete college students who were SES matched to the football player group (total N  = 51)...
2018: NeuroImage: Clinical
Alireza Shahbabaie, Mitra Ebrahimpoor, Ali Hariri, Michael A Nitsche, Javad Hatami, Emad Fatemizadeh, Mohammad Ali Oghabian, Hamed Ekhtiari
Background: Transcranial direct current stimulation (tDCS) is a noninvasive brain stimulation tool suited to alter cortical excitability and activity via the application of weak direct electrical currents. An increasing number of studies in the addiction literature suggests that tDCS modulates subjective self-reported craving through stimulation of dorsolateral prefrontal cortex (DLPFC). The major goal of this study was to explore effects of bilateral DLPFC stimulation on resting state networks (RSNs) in association with drug craving modulation...
March 2018: Brain and Behavior
Dorothea L Floris, Meng-Chuan Lai, Tanmay Nath, Michael P Milham, Adriana Di Martino
Background: The male predominance in the prevalence of autism spectrum disorder (ASD) has motivated research on sex differentiation in ASD. Multiple sources of evidence have suggested a neurophenotypic convergence of ASD-related characteristics and typical sex differences. Two existing, albeit competing, models provide predictions on such neurophenotypic convergence. These two models are testable with neuroimaging. Specifically, the Extreme Male Brain (EMB) model predicts that ASD is associated with enhanced brain maleness in both males and females with ASD (i...
2018: Molecular Autism
Jiayue Cai, Soojin Lee, Fang Ba, Saurabh Garg, Laura J Kim, Aiping Liu, Diana Kim, Z Jane Wang, Martin J McKeown
Falls and balance difficulties remain a major source of morbidity in Parkinson's Disease (PD) and are stubbornly resistant to therapeutic interventions. The mechanisms of gait impairment in PD are incompletely understood but may involve changes in the Pedunculopontine Nucleus (PPN) and its associated connections. We utilized fMRI to explore the modulation of PPN connectivity by Galvanic Vestibular Stimulation (GVS) in healthy controls ( n = 12) and PD subjects even without overt evidence of Freezing of Gait (FOG) while on medication ( n = 23)...
2018: Frontiers in Neuroscience
Poornima Kumar, Franziska Goer, Laura Murray, Daniel G Dillon, Miranda L Beltzer, Andrew L Cohen, Nancy H Brooks, Diego A Pizzagalli
Anhedonia (hyposensitivity to rewards) and negative bias (hypersensitivity to punishments) are core features of major depressive disorder (MDD), which could stem from abnormal reinforcement learning. Emerging evidence highlights blunted reward learning and reward prediction error (RPE) signaling in the striatum in MDD, although inconsistencies exist. Preclinical studies have clarified that ventral tegmental area (VTA) neurons encode RPE and habenular neurons encode punishment prediction error (PPE), which are then transmitted to the striatum and cortex to guide goal-directed behavior...
February 26, 2018: Neuropsychopharmacology: Official Publication of the American College of Neuropsychopharmacology
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