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Hang Joon Jo, Kevin W McCairn, William S Gibson, Paola Testini, Cong Zhi Zhao, Krzysztof R Gorny, Joel P Felmlee, Kirk M Welker, Charles D Blaha, Bryan T Klassen, Hoon-Ki Min, Kendall H Lee
Background and objectives: Deep brain stimulation (DBS) of the thalamus is a promising therapeutic alternative for treating medically refractory Tourette syndrome (TS). However, few human studies have examined its mechanism of action. Therefore, the networks that mediate the therapeutic effects of thalamic DBS remain poorly understood. Methods: Five participants diagnosed with severe medically refractory TS underwent bilateral thalamic DBS stereotactic surgery. Intraoperative fMRI characterized the blood oxygen level-dependent (BOLD) response evoked by thalamic DBS and determined whether the therapeutic effectiveness of thalamic DBS, as assessed using the Modified Rush Video Rating Scale test, would correlate with evoked BOLD responses in motor and limbic cortical and subcortical regions...
2018: NeuroImage: Clinical
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
Bei-Bei Wu, Ye Ma, Lei Xie, Jin-Zhuang Huang, Zong-Bo Sun, Zhi-Duo Hou, Rui-Wei Guo, Zhi-Rong Lin, Shou-Xing Duan, Shan-Shan Zhao, Yao-Xie, Dan-Miao Sun, Chun-Min Zhu, Shu-Hua Ma
BACKGROUND: Systemic lupus erythematosus (SLE) is associated with cognitive deficit but the exact neural mechanisms remain unclear. PURPOSE: To explore sequential brain activities using functional magnetic resonance imaging (fMRI) during the performance of a decision-making task, and to determine whether serum or clinical markers can reflect the involvement of the brain in SLE. SUBJECTS: Sixteen female SLE patients without overt clinical neuropsychiatric symptoms and 16 healthy controls were included...
March 14, 2018: Journal of Magnetic Resonance Imaging: JMRI
Martin Lamos, Radek Marecek, Tomáš Slavíček, Michal Mikl, Ivan Rektor, Jiri Jan
Growing interest in the examination of large-scale brain network functional connectivity dynamics is accompanied by an effort to find the electrophysiological correlates. The commonly used constraints applied to spatial and spectral domains during EEG data analysis may leave part of the neural activity unrecognized. We propose an approach that blindly reveals multimodal EEG spectral patterns that are related to the dynamics of the BOLD functional network connectivity.
 Approach. The blind decomposition of EEG spectrogram by Parallel Factor Analysis has been shown to be a useful technique for uncovering patterns of neural activity...
March 14, 2018: Journal of Neural Engineering
Pengmin Qin, Niall W Duncan, David Yen-Ting Chen, Chi-Jen Chen, Li-Kai Huang, Zirui Huang, Chien-Yuan E Lin, Christine Wiebking, Che-Ming Yang, Georg Northoff, Timothy Lane
Neural activity varies continually from moment to moment. Such temporal variability (TV) has been highlighted as a functionally specific brain property playing a fundamental role in cognition. We sought to investigate the mechanisms involved in TV changes between two basic behavioural states, namely having the eyes open (EO) or eyes closed (EC) in vivo in humans. To these ends we acquired BOLD fMRI, ASL, and [18 F]-fluoro-deoxyglucose PET in a group of healthy participants (n = 15), along with BOLD fMRI and [18 F]-flumazenil PET in a separate group (n = 19)...
March 9, 2018: Neuroscience
Logan T Dowdle, Truman R Brown, Mark S George, Colleen A Hanlon
BACKGROUND: In the 20 years since our group established the feasibility of performing interleaved TMS/fMRI, no studies have reported direct comparisons of active prefrontal stimulation with a matched sham. Thus, for all studies there is concern about what is truly the TMS effect on cortical neurons. OBJECTIVE: After developing a sham control for use within the MRI scanner, we used fMRI to test the hypothesis of greater regional BOLD responses for active versus control stimulation...
February 24, 2018: Brain Stimulation
Grigori Yourganov, Julius Fridriksson, Brielle Stark, Christopher Rorden
We examined the effect of lesion on the resting-state functional connectivity in chronic post-stroke patients. We found many instances of strong correlations in BOLD signal measured at different locations within the lesion, making it hard to distinguish from the connectivity between intact and strongly connected regions. Regression of the mean cerebro-spinal fluid signal did not alleviate this problem. The connectomes computed by exclusion of lesioned voxels were not good predictors of the behavioral measures...
2018: NeuroImage: Clinical
Elshin Mathias, Allanah Kenny, Michael J Plank, Tim David
A state-of-the-art integrated model of neurovascular coupling (NVC) [19, 18, 38] and the BOLD response [47, 48] is presented with the ability to simulate the fMRI BOLD responses due to continuous neuronal spiking, bursting and cortical spreading depression (CSD) along with the underlying complex vascular coupling. Simulated BOLD responses are compared to experimental BOLD signals observed in the rat barrel cortex and in the hippocampus under seizure conditions showing good agreement. Bursting phenomena provides relatively clear BOLD signals as long as the time between bursts is not too short...
March 8, 2018: NeuroImage
Catarina Amado, Polina Stoyanova, Gyula Kovács
Several electrophysiological studies found response differences to a given stimulus when it is repeated frequently as compared to when it occurs rarely in oddball sequences. Initially defined in acoustic perception, such difference also exists in the visual modality and is referred to as visual mismatch negativity (vMMN). However, the repetition of a stimulus also leads to the reduction of the blood oxygen-level dependent (BOLD) signal (fMRI adaptation, fMRIa) when compared to alternating stimuli in fMRI experiments...
March 7, 2018: Behavioural Brain Research
Shruti G Vij, Jason S Nomi, Dina R Dajani, Lucina Q Uddin
Development and aging are associated with functional changes in the brain across the lifespan. These changes manifest in a variety of spatial and temporal features of resting state functional MRI (rs-fMRI) but have seldom been explored exhaustively. We present a comprehensive study assessing age-related changes in spatial and temporal features of blind-source separated components identified by independent vector analysis (IVA) in a cross-sectional lifespan sample (ages 6-85 years). We show that while large-scale network configurations remain consistent throughout the lifespan, changes persist in both local and global organization of these networks...
March 6, 2018: NeuroImage
Vanessa Scarapicchia, Erin L Mazerolle, John D Fisk, Lesley J Ritchie, Jodie R Gawryluk
Background: Alzheimer's disease (AD) is a neurodegenerative disorder that may benefit from early diagnosis and intervention. Therefore, there is a need to identify early biomarkers of AD using non-invasive techniques such as functional magnetic resonance imaging (fMRI). Recently, novel approaches to the analysis of resting-state fMRI data have been developed that focus on the moment-to-moment variability in the blood oxygen level dependent (BOLD) signal. The objective of the current study was to investigate BOLD variability as a novel early biomarker of AD and its associated psychophysiological correlates...
2018: Frontiers in Aging Neuroscience
Yujia Zhou, Han Zhang, Lichi Zhang, Xiaohuan Cao, Ru Yang, Qianjin Feng, Pew-Thian Yap, Dinggang Shen
Population studies of brain function with resting-state functional magnetic resonance imaging (rs-fMRI) rely on accurate intersubject registration of functional areas. This is typically achieved through registration using high-resolution structural images with more spatial details and better tissue contrast. However, accumulating evidence has suggested that such strategy cannot align functional regions well because functional areas are not necessarily consistent with anatomical structures. To alleviate this problem, a number of registration algorithms based directly on rs-fMRI data have been developed, most of which utilize functional connectivity (FC) features for registration...
March 5, 2018: Human Brain Mapping
Julio Dueñas, James Sulzer, Philipp Stämpfli, Marie-Claude Hepp-Reymond, Spyros Kollias, Erich Seifritz, Roger Gassert
Peripheral encoding of movement kinematics has been well-characterized, but there is little understanding of the relationship between movement kinematics and associated brain activation. We hypothesized that kinematics of passive movement is differentially represented in the sensorimotor network, reflecting the well-studied afferent responses to movement. A robotic forefinger manipulandum was used to induce passive kinematic stimuli and monitor interaction force in 41 healthy participants during whole-brain functional magnetic resonance imaging (fMRI)...
February 28, 2018: NeuroImage
Hugo Angleys, Sune N Jespersen, Leif Østergaard
Neurovascular coupling mechanisms give rise to vasodilation and functional hyperemia upon neural activation, thereby altering blood oxygenation. This blood oxygenation level dependent (BOLD) contrast allows studies of activation patterns in the working human brain by functional MRI (fMRI). The BOLD-weighted fMRI signal shows characteristic transients in relation to functional activation, such as the so-called initial dip, overshoot, and post-stimulus undershoot. These transients are modulated by other physiological stimuli and in disease, but the underlying physiological mechanisms remain incompletely understood...
March 2, 2018: Human Brain Mapping
Siyang Yin, Yuelu Liu, Nathan M Petro, Andreas Keil, Mingzhou Ding
Research in rodents has established the role of the amygdaloid complex in defensive responses to conditioned threat. In human imaging studies, however, activation of the amygdala by conditioned threat cues is often not observed. One hypothesis states that this finding reflects adaptation of amygdaloid responses over time. We tested this hypothesis by estimating single-trial neural responses over a large number of conditioning trials. Functional MRI (fMRI) was recorded from 18 participants during classical differential fear conditioning: Participants viewed oriented grayscale grating stimuli (45° or 135°) presented centrally in random order...
January 2018: ENeuro
Fatma Gargouri, Fathi Kallel, Sebastien Delphine, Ahmed Ben Hamida, Stéphane Lehéricy, Romain Valabregue
Resting state functional MRI (rs-fMRI) is an imaging technique that allows the spontaneous activity of the brain to be measured. Measures of functional connectivity highly depend on the quality of the BOLD signal data processing. In this study, our aim was to study the influence of preprocessing steps and their order of application on small-world topology and their efficiency in resting state fMRI data analysis using graph theory. We applied the most standard preprocessing steps: slice-timing, realign, smoothing, filtering, and the tCompCor method...
2018: Frontiers in Computational Neuroscience
Prantik Kundu, Brenda E Benson, Dana Rosen, Sophia Frangou, Ellen Leibenluft, Wen-Ming Luh, Peter A Bandettini, Daniel S Pine, Monique Ernst
Age-related changes in human functional neuroanatomy are poorly understood. This is partly due to the limits to interpretation of standard fMRI. These limits relate to age-related variation in noise levels across subjects, and the frequent need for standard adult parcellations in developmental studies. Here we used an emerging MRI approach called multi-echo (ME)-fMRI to characterize functional brain changes with age. ME-fMRI acquires blood oxygenation level dependent (BOLD) signals while also quantifying T2* signal decay...
February 27, 2018: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
Vincenzo G Fiore, Tobias Nolte, Francesco Rigoli, Peter Smittenaar, Xiaosi Gu, Raymond J Dolan
The external part of the globus pallidus (GPe) is a core nucleus of the basal ganglia (BG) whose activity is disrupted under conditions of low dopamine release, as in Parkinson's disease. Current models assume decreased dopamine release in the dorsal striatum results in deactivation of dorsal GPe, which in turn affects motor expression via a regulatory effect on other nuclei of the BG. However, recent studies in healthy and pathological animal models have reported neural dynamics that do not match with this view of the GPe as a relay in the BG circuit...
February 23, 2018: NeuroImage
Anupa A Vijayakumari, Bejoy Thomas, Ramshekhar N Menon, Chandrasekharan Kesavadas
Functional MRI (fMRI) has provided much insight into the changes in the neuronal activity on the basis of blood oxygen level dependent (BOLD) phenomenon. The dynamic changes in the metabolites can be detected using functional proton magnetic resonance spectroscopy (H-fMRS). The strategy of combining fMRI and H-fMRS would facilitate the understanding of the neurochemical interpretation of the BOLD signal. The dorsolateral prefrontal region is critically involved in the processing of working memory (WM), as demonstrated by the studies involving the neuroimaging, neuropsychological, and electrophysiological experiments...
February 23, 2018: Neuroreport
Jing Lu, Sijia Guo, Mingming Chen, Weixia Wang, Hua Yang, Daqing Guo, Dezhong Yao
Many methods have been developed to translate a human electroencephalogram (EEG) into music. In addition to EEG, functional magnetic resonance imaging (fMRI) is another method used to study the brain and can reflect physiological processes. In 2012, we established a method to use simultaneously recorded fMRI and EEG signals to produce EEG-fMRI music, which represents a step toward scale-free brain music. In this study, we used a neural mass model, the Jansen-Rit model, to simulate activity in several cortical brain regions...
January 2018: Medicine (Baltimore)
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