scholarly journals Noninvasive targeted neuromodulation and functional imaging in behaving macaques

2018 ◽  
Author(s):  
Charles F. Caskey ◽  
Jeffrey Schall ◽  
William Grissom ◽  
Wolf Zinke ◽  
Josh Cosman ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Focused Ultrasound ◽  
Macaque Monkey ◽  
Disease Diagnosis ◽  
Blood Oxygen Level Dependent ◽  
Neural Stimulation ◽  
Frontal Eye Field ◽  
Blood Oxygen Level ◽  
Brain Circuits ◽  
The Brain

All presently available neural stimulation methods are either invasive or can only be moderately localized, and a neurostimulation method that could overcome these limitations would be invaluable for the mapping of brain circuits, disease diagnosis in the brain, neurosurgery and therapy. Neural stimulation with magnetic resonance guided focused ultrasound (MRgFUS) is a promising technology that can noninvasively excite or inhibit neural activity in well-defined discrete volumes of the brain, subsequently enabling investigation of brain circuits with magnetic resonance imaging (MRI). In this study, we seek to explore ultrasonic neuromodulation in the frontal eye field of a macaque monkey, while measuring the effects of neuromodulation via eventrelated potentials, behavioral responses, and blood oxygen level dependent functional MRI.

scholarly journals Blood Oxygen Level–Dependent Magnetic Resonance Imaging Identifies Cortical Hypoxia in Severe Renovascular Disease

Hypertension ◽  
2011 ◽  
Vol 58 (6) ◽  
pp. 1066-1072 ◽  
Author(s):  
Monika L. Gloviczki ◽  
James F. Glockner ◽  
John A. Crane ◽  
Michael A. McKusick ◽  
Sanjay Misra ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Blood Oxygen Level Dependent ◽  
Blood Oxygen ◽  
Oxygen Level ◽  
Resonance Imaging ◽  
Blood Oxygen Level ◽  
Renovascular Disease

MAGNETIC RESONANCE IMAGING-GUIDED FOCUSED ULTRASOUND FOR THERMAL ABLATION IN THE BRAIN

Neurosurgery ◽  
2007 ◽  
Vol 60 (4) ◽  
pp. 593-600 ◽  
Author(s):  
Zvi R. Cohen ◽  
Jacob Zaubermann ◽  
Sagi Harnof ◽  
Yael Mardor ◽  
Dvora Nass ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Thermal Ablation ◽  
Focused Ultrasound ◽  
Resonance Imaging ◽  
The Brain

scholarly journals Measurement of CMRO2 and its relationship with CBF in hypoxia with an extended calibrated BOLD method

2019 ◽  
Vol 40 (10) ◽  
pp. 2066-2080
Author(s):  
Yaoyu Zhang ◽  
Yayan Yin ◽  
Huanjie Li ◽  
Jia-Hong Gao
Keyword(s):  
Cerebral Blood Volume ◽  
Pulse Sequence ◽  
Blood Oxygen Level Dependent ◽  
Extended Model ◽  
Brain Health ◽  
Blood Oxygen Level ◽  
Oxygen Conditions ◽  
Health And Disease ◽  
The Brain ◽  
Mild Hypoxia

Cerebral blood flow (CBF) and cerebral metabolic rate of oxygen (CMRO2) are physiological parameters that not only reflect brain health and disease but also jointly contribute to blood oxygen level-dependent (BOLD) signals. Nevertheless, unsolved issues remain concerning the CBF–CMRO2 relationship in the working brain under various oxygen conditions. In particular, the CMRO2 responses to functional tasks in hypoxia are less studied. We extended the calibrated BOLD model to incorporate CMRO2 measurements in hypoxia. The extended model, which was cross-validated with a multicompartment BOLD model, considers the influences of the reduced arterial saturation level and increased baseline cerebral blood volume (CBV) and deoxyhemoglobin concentration on the changes of BOLD signals in hypoxia. By implementing a pulse sequence to simultaneously acquire the CBV-, CBF- and BOLD-weighted signals, we investigated the effects of mild hypoxia on the CBF and CMRO2 responses to graded visual stimuli. Compared with normoxia, mild hypoxia caused significant alterations in both the amplitude and the trend of the CMRO2 responses but did not impact the corresponding CBF responses. Our observations suggested that the flow-metabolism coupling strategies in the brain during mild hypoxia were different from those during normoxia.

Interhemispheric Integration at Different Spatial Scales: The Evidence From EEG Coherence and fMRI

2006 ◽  
Vol 96 (1) ◽  
pp. 259-275 ◽  
Author(s):  
Maria G. Knyazeva ◽  
Eleonora Fornari ◽  
Reto Meuli ◽  
Philippe Maeder
Keyword(s):  
Spatial Scales ◽  
Neural Substrates ◽  
Blood Oxygen Level Dependent ◽  
Specific Information ◽  
Eeg Coherence ◽  
Blood Oxygen Level ◽  
Spatial Frequencies ◽  
Collateral Sulcus ◽  
Gestalt Grouping ◽  
The Brain

The early visual system processes different spatial frequencies (SFs) separately. To examine where in the brain the scale-specific information is integrated, we mapped the neural assemblies engaged in interhemispheric coupling with electroencephalographic (EEG) coherence and blood-oxygen-level dependent (BOLD) signal. During similar EEG and functional magnetic resonance imaging (fMRI) experiments, our subjects viewed centrally presented bilateral gratings of different SF (0.25–8.0 cpd), which either obeyed Gestalt grouping rules (iso-oriented, IG) or violated them (orthogonally oriented, OG). The IG stimuli (0.5–4.0 cpd) synchronized EEG at discrete beta frequencies (beta1, beta2) and increased BOLD (0.5 and 2.0 cpd tested) in ventral (around collateral sulcus) and dorsal (parieto-occipital fissure) regions compared with OG. At both SF, the beta1 coherence correlated with the ventral activations, whereas the beta2 coherence correlated with the dorsal ones. Thus distributed neural substrates mediated interhemispheric integration at single SF. The relative impact of the ventral versus dorsal networks was modulated by the SF of the stimulus.

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