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BOLD fMRI

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https://www.readbyqxmd.com/read/29331056/exploring-the-advantages-of-multiband-fmri-with-simultaneous-eeg-to-investigate-coupling-between-gamma-frequency-neural-activity-and-the-bold-response-in-humans
#1
Makoto Uji, Ross Wilson, Susan T Francis, Karen J Mullinger, Stephen D Mayhew
We established an optimal combination of EEG recording during sparse multiband (MB) fMRI that preserves high-resolution, whole-brain fMRI coverage while enabling broad-band EEG recordings which are uncorrupted by MRI gradient artefacts (GAs). We first determined the safety of simultaneous EEG recording during MB fMRI. Application of MB factor = 4 produced <1°C peak heating of electrode/hardware during 20 min of GE-EPI data acquisition. However, higher SAR sequences require specific safety testing, with greater heating observed using PCASL with MB factor = 4...
January 13, 2018: Human Brain Mapping
https://www.readbyqxmd.com/read/29329693/bold-fmri-signal-in-stroke-patients-and-its-importance-for-prognosis-in-the-subacute-disease-period-preliminary-report
#2
Anetta Lasek-Bal, Joanna Kidoń, Monika Błaszczyszyn, Bartłomiej Stasiów, Amadeusz Żak
Functional magnetic resonance imaging (fMRI) allows for the assessment of neuronal activity through the blood-level-dependent signal. The purpose of study was to evaluate the pattern of brain activity in fMRI in patients with ischemic stroke and to assess the potential relationship between the activity pattern and the neurological/functional status. METHODS: The fMRI was performed in patients up to 4th day of stroke. All the patients were analyzed according to NIHSS on 1st day and mRankin scale on 14th day of stroke, followed by analyzing of fMRI signal...
December 24, 2017: Neurologia i Neurochirurgia Polska
https://www.readbyqxmd.com/read/29329062/amygdala-response-to-emotional-faces-in-seasonal-affective-disorder
#3
Camilla Borgsted, Brice Ozenne, Brenda Mc Mahon, Martin K Madsen, Liv V Hjordt, Ida Hageman, William F C Baaré, Gitte M Knudsen, Patrick M Fisher
BACKGROUND: Seasonal affective disorder (SAD) is characterized by seasonally recurring depression. Heightened amygdala activation to aversive stimuli is associated with major depressive disorder but its relation to SAD is unclear. We evaluated seasonal variation in amygdala activation in SAD and healthy controls (HC) using a longitudinal design targeting the asymptomatic/symptomatic phases of SAD. We hypothesized increased amygdala activation to aversive stimuli in the winter in SAD individuals (season-by-group interaction)...
January 3, 2018: Journal of Affective Disorders
https://www.readbyqxmd.com/read/29311140/visual-short-term-memory-activity-in-parietal-lobe-reflects-cognitive-processes-beyond-attentional-selection
#4
Summer L Sheremata, David C Somers, Sarah Shomstein
Visual attention and short-term memory (VSTM) are distinct yet inter-related processes. While both require selection of information across the visual field, memory additionally requires maintenance of information across time and distraction. VSTM recruits areas within human (male and female) dorsal and ventral parietal cortex that are also implicated in spatial selection, therefore, it is important to determine if overlapping activation might reflect shared attentional demands. Here, identical stimuli and controlled sustained attention across both tasks were used to ask whether fMRI signal amplitude, functional connectivity, and contralateral visual field bias reflect memory-specific task demands...
January 8, 2018: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/29310867/motor-practice-in-a-force-modulation-task-in-young-and-middle-aged-adults
#5
Ben Godde, Mireille Trautmann, Peter Erhard, Claudia Voelcker-Rehage
Learning new motor skills is important for everyday life and independent living in older age. While studies on motor sequence learning and motor adaptation revealed age differences that are mostly related to frontal decline with increasing age, data for fine finger force modulation are missing. Twelve young (YA, 18-28 years) and twelve middle-aged older (OA, 55-65 years) adults practiced a force modulation task in precision grip while lying in a 3T MR scanner. Participants followed a sine wave between 5 and 25% of their maximum voluntary contraction (MVC) at a frequency of 0...
December 24, 2017: Journal of Electromyography and Kinesiology
https://www.readbyqxmd.com/read/29305037/transauricular-vagus-nerve-stimulation-at-auricular-acupoints-kindey-co10-yidan-co11-liver-co12-and-shenmen-tf4-can-induce-auditory-and-limbic-cortices-activation-measured-by-fmri
#6
Liyan Peng, Ketao Mu, Aiguo Liu, Liangqiang Zhou, Yueyue Gao, Imrit Tejvansh Shenoy, Zhigang Mei, Qingguo Chen
The purpose of this study was to explore the central mechanism of transauricular vagus nerve stimulation (taVNS) to human by fMRI and to find a suitable taVNS site for potential tinnitus treatment. 24 healthy subjects aged between 28 and 38 years were enrolled in the experiment. 8 subjects were stimulated in the auricular acupoints Kindey (CO10), Yidan (CO11), Liver (CO12) and Shenmen (TF4) in the left ear, 8 subjects were stimulated at the anterior wall of the auditory canal and left lower limb as an anterior stimulation group; 8 persons who were arranged in a sham group received taVNS at the left ear lobe and tail of the helix...
December 24, 2017: Hearing Research
https://www.readbyqxmd.com/read/29298164/neural-activity-during-mental-rotation-in-deaf-signers-the-influence-of-long-term-sign-language-experience
#7
Hong-Bo Le, Hui-Hong Zhang, Qiu-Lin Wu, Jiong Zhang, Jing-Jing Yin, Shu-Hua Ma
OBJECTIVES: Mental rotation is the brain's visuospatial understanding of what objects are and where they belong. Previous research indicated that deaf signers showed behavioral enhancement for nonlinguistic visual tasks, including mental rotation. In this study, we investigated the neural difference of mental rotation processing between deaf signers and hearing nonsigners using blood oxygen level-dependent (BOLD) functional magnetic resonance imaging (fMRI). DESIGN: The participants performed a block-designed experiment, consisting of alternating blocks of comparison and rotation periods, separated by a baseline or fixation period...
January 2, 2018: Ear and Hearing
https://www.readbyqxmd.com/read/29288128/identifying-and-characterizing-systematic-temporally-lagged-bold-artifacts
#8
Lisa Byrge, Daniel P Kennedy
Residual noise in the BOLD signal remains problematic for fMRI - particularly for techniques such as functional connectivity, where findings can be spuriously influenced by noise sources that can covary with individual differences. Many such potential noise sources - for instance, motion and respiration - can have a temporally lagged effect on the BOLD signal. Thus, here we present a tool for assessing residual lagged structure in the BOLD signal that is associated with nuisance signals, using a construction similar to a peri-event time histogram...
December 26, 2017: NeuroImage
https://www.readbyqxmd.com/read/29286444/generalized-psychophysiological-interaction-ppi-analysis-of-memory-related-connectivity-in-individuals-at-genetic-risk-for-alzheimer-s-disease
#9
Theresa M Harrison, Donald G McLaren, Teena D Moody, Jamie D Feusner, Susan Y Bookheimer
In neuroimaging, functional magnetic resonance imaging (fMRI) measures the blood-oxygenation-level dependent (BOLD) signal in the brain. The degree of correlation of the BOLD signal in spatially independent regions of the brain defines the functional connectivity of those regions. During a cognitive fMRI task, a psychophysiological interaction (PPI) analysis can be used to examine changes in the functional connectivity during specific contexts defined by the cognitive task. An example of such a task is one that engages the memory system, asking participants to learn pairs of unrelated words (encoding) and recall the second word in a pair when presented with the first word (retrieval)...
November 14, 2017: Journal of Visualized Experiments: JoVE
https://www.readbyqxmd.com/read/29285809/investigation-of-the-bold-and-cbv-fmri-responses-to-somatosensory-stimulation-in-awake-marmosets-callithrix-jacchus
#10
Yoshiyuki Hirano, Cecil C Yen, Junjie V Liu, Julie B Mackel, Hellmut Merkle, George C Nascimento, Bojana Stefanovic, Afonso C Silva
Understanding the spatiotemporal features of the hemodynamic response function (HRF) to brain stimulation is essential for the correct application of neuroimaging methods to study brain function. Here, we investigated the spatiotemporal evolution of the blood oxygen level-dependent (BOLD) and cerebral blood volume (CBV) HRF in conscious, awake marmosets (Callithrix jacchus), a New World non-human primate with a lissencephalic brain and with growing use in biomedical research. The marmosets were acclimatized to head fixation and placed in a 7-T magnetic resonance imaging (MRI) scanner...
December 29, 2017: NMR in Biomedicine
https://www.readbyqxmd.com/read/29277650/macroscale-variation-in-resting-state-neuronal-activity-and-connectivity-assessed-by-simultaneous-calcium-imaging-hemodynamic-imaging-and-electrophysiology
#11
Matthew C Murphy, Kevin C Chan, Seong-Gi Kim, Alberto L Vazquez
Functional imaging of spontaneous activity continues to play an important role in the field of connectomics. The most common imaging signal used for these experiments is the blood-oxygen-level-dependent (BOLD) functional MRI (fMRI) signal, but how this signal relates to spontaneous neuronal activity remains incompletely understood. Genetically encoded calcium indicators represent a promising tool to study this problem, as they can provide brain-wide measurements of neuronal activity compared to point measurements afforded by electrophysiological recordings...
December 22, 2017: NeuroImage
https://www.readbyqxmd.com/read/29276390/trial-level-regressor-modulation-for-functional-magnetic-resonance-imaging-designs-requiring-strict-periodicity-of-stimulus-presentations-illustrated-using-a-go-no-go-task
#12
Michael A Motes, Neena K Rao, Ehsan Shokri-Kojori, Hsueh-Sheng Chiang, Michael A Kraut, John Hart
Computer-based assessment of many cognitive processes (eg, anticipatory and response readiness processes) requires the use of invariant stimulus display times (SDT) and intertrial intervals (ITI). Although designs with invariant SDTs and ITIs have been used in functional magnetic resonance imaging (fMRI) research, such designs are problematic for fMRI studies because of collinearity issues. This study examined regressor modulation with trial-level reaction times (RT) as a method for improving signal detection in a go/no-go task with invariant SDTs and ITIs...
2017: Magnetic Resonance Insights
https://www.readbyqxmd.com/read/29249950/non-linear-relationship-between-bold-activation-and-amplitude-of-beta-oscillations-in-the-supplementary-motor-area-during-rhythmic-finger-tapping-and-internal-timing
#13
Florian Gompf, Anja Pflug, Helmut Laufs, Christian A Kell
Functional imaging studies using BOLD contrasts have consistently reported activation of the supplementary motor area (SMA) both during motor and internal timing tasks. Opposing findings, however, have been shown for the modulation of beta oscillations in the SMA. While movement suppresses beta oscillations in the SMA, motor and non-motor tasks that rely on internal timing increase the amplitude of beta oscillations in the SMA. These independent observations suggest that the relationship between beta oscillations and BOLD activation is more complex than previously thought...
2017: Frontiers in Human Neuroscience
https://www.readbyqxmd.com/read/29249925/determining-excitatory-and-inhibitory-neuronal-activity-from-multimodal-fmri-data-using-a-generative-hemodynamic-model
#14
Martin Havlicek, Dimo Ivanov, Alard Roebroeck, Kamil Uludağ
Hemodynamic responses, in general, and the blood oxygenation level-dependent (BOLD) fMRI signal, in particular, provide an indirect measure of neuronal activity. There is strong evidence that the BOLD response correlates well with post-synaptic changes, induced by changes in the excitatory and inhibitory (E-I) balance between active neuronal populations. Typical BOLD responses exhibit transients, such as the early-overshoot and post-stimulus undershoot, that can be linked to transients in neuronal activity, but they can also result from vascular uncoupling between cerebral blood flow (CBF) and venous cerebral blood volume (venous CBV)...
2017: Frontiers in Neuroscience
https://www.readbyqxmd.com/read/29246846/leica-laplacian-eigenmaps-for-group-ica-decomposition-of-fmri-data
#15
Chihuang Liu, Joseph JaJa, Luiz Pessoa
Independent component analysis (ICA) is a data-driven method that has been increasingly used for analyzing functional Magnetic Resonance Imaging (fMRI) data. However, generalizing ICA to multi-subject studies is non-trivial due to the high-dimensionality of the data, the complexity of the underlying neuronal processes, the presence of various noise sources, and inter-subject variability. Current group ICA based approaches typically use several forms of the Principal Component Analysis (PCA) method to extend ICA for generating group inferences...
December 12, 2017: NeuroImage
https://www.readbyqxmd.com/read/29226709/enhanced-brain-network-activity-in-complex-movement-rhythms-a-simultaneous-fmri-eeg-study
#16
Bhim Mani Adhikari, Charles M Epstein, Mukesh Dhamala
Generating movement rhythms is known to involve a network of distributed brain regions associated with motor planning, control, execution, and perception of timing for the repertoire of motor actions. What brain areas are bound in the network and how the network activity is modulated by rhythmic complexity have not been completely explored. To contribute to answering these questions, we designed a study in which nine healthy participants performed simple to complex rhythmic finger movement tasks while undergoing simultaneous functional magnetic resonance imaging and electroencephalography (fMRI-EEG) recordings of their brain activity during the tasks and rest...
December 10, 2017: Brain Connectivity
https://www.readbyqxmd.com/read/29226283/improving-functional-mri-registration-using-whole-brain-functional-correlation-tensors
#17
Yujia Zhou, Pew-Thian Yap, Han Zhang, Lichi Zhang, Qianjin Feng, Dinggang Shen
Population studies of brain function with resting-state functional magnetic resonance imaging (rs-fMRI) largely rely on the accurate inter-subject registration of functional areas. This is typically achieved through registration of the corresponding T1-weighted MR images with more structural details. However, accumulating evidence has suggested that such strategy cannot well-align functional regions which are not necessarily confined by the anatomical boundaries defined by the T1-weighted MR images. To mitigate this problem, various registration algorithms based directly on rs-fMRI data have been developed, most of which have utilized functional connectivity (FC) as features for registration...
September 2017: Medical Image Computing and Computer-assisted Intervention: MICCAI ..
https://www.readbyqxmd.com/read/29226267/orbitofrontal-cortex-activity-and-connectivity-predict-future-depression-symptoms-in-adolescence
#18
Jingwen Jin, Ananth Narayanan, Greg Perlman, Katherine Luking, Christine DeLorenzo, Greg Hajcak, Daniel N Klein, Roman Kotov, Aprajita Mohanty
Background: Major depressive disorder is a leading cause of disability worldwide; however, little is known about pathological mechanisms involved in its development. Research in adolescent depression has focused on reward sensitivity and striatal mechanisms implementing it. The contribution of loss sensitivity to future depression, as well as the orbitofrontal cortex (OFC) mechanisms critical for processing losses and rewards, remain unexplored. Furthermore, it is unclear whether OFC functioning interacts with familial history in predicting future depression...
October 2017: Biological Psychiatry: Cognitive Neuroscience and Neuroimaging
https://www.readbyqxmd.com/read/29224727/high-resolution-cbv-fmri-allows-mapping-of-laminar-activity-and-connectivity-of-cortical-input-and-output-in-human-m1
#19
Laurentius Huber, Daniel A Handwerker, David C Jangraw, Gang Chen, Andrew Hall, Carsten Stüber, Javier Gonzalez-Castillo, Dimo Ivanov, Sean Marrett, Maria Guidi, Jozien Goense, Benedikt A Poser, Peter A Bandettini
Layer-dependent fMRI allows measurements of information flow in cortical circuits, as afferent and efferent connections terminate in different cortical layers. However, it is unknown to what level human fMRI is specific and sensitive enough to reveal directional functional activity across layers. To answer this question, we developed acquisition and analysis methods for blood-oxygen-level-dependent (BOLD) and cerebral-blood-volume (CBV)-based laminar fMRI and used these to discriminate four different tasks in the human motor cortex (M1)...
December 20, 2017: Neuron
https://www.readbyqxmd.com/read/29217224/the-neural-correlates-of-self-referential-memory-encoding-and-retrieval-in-schizophrenia
#20
Amy M Jimenez, Junghee Lee, Jonathan K Wynn, Michael F Green
BACKGROUND: Enhanced memory for self-oriented information is known as the self-referential memory (SRM) effect. fMRI studies of the SRM effect have focused almost exclusively on encoding, revealing selective engagement of the medial prefrontal cortex (mPFC) during "self" relative to other processing conditions. Other critical areas for self-processing include ventrolateral prefrontal cortex (vlPFC), temporo-parietal junction (TPJ) and posterior cingulate/precuneus (PCC/PC). Previous behavioral studies show that individuals with schizophrenia fail to benefit from this memory boost...
December 4, 2017: Neuropsychologia
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