Magnetoencephalography: physics, techniques, and applications in the basic and clinical neurosciences

2021 ◽  
Vol 125 (3) ◽  
pp. 938-956
Author(s):  
Junseok A. Kim ◽  
Karen D. Davis
Keyword(s):  
Brain Activity ◽  
Emission Tomography ◽  
Functional Coupling ◽  
High Temporal Resolution ◽  
Resonance Imaging ◽  
Advantages And Disadvantages ◽  
Current Review ◽  
Positron Emission ◽  
Basic Features ◽  
The Brain

Magnetoencephalography (MEG) is a technique used to measure the magnetic fields generated from neuronal activity in the brain. MEG has a high temporal resolution on the order of milliseconds and provides a more direct measure of brain activity when compared with hemodynamic-based neuroimaging methods such as magnetic resonance imaging and positron emission tomography. The current review focuses on basic features of MEG such as the instrumentation and the physics that are integral to the signals that can be measured, and the principles of source localization techniques, particularly the physics of beamforming and the techniques that are used to localize the signal of interest. In addition, we review several metrics that can be used to assess functional coupling in MEG and describe the advantages and disadvantages of each approach. Lastly, we discuss the current and future applications of MEG.

A Review on Brain Imaging Techniques for BCI Applications

2016 ◽  
pp. 39-70
Author(s):  
Saugat Bhattacharyya ◽  
Anwesha Khasnobish ◽  
Poulami Ghosh ◽  
Ankita Mazumder ◽  
D. N. Tibarewala
Keyword(s):  
Magnetic Resonance Imaging ◽  
Positron Emission Tomography ◽  
Magnetic Resonance ◽  
Brain Imaging ◽  
Near Infrared ◽  
Emission Tomography ◽  
Resonance Imaging ◽  
Functional Near Infrared Spectroscopy ◽  
Positron Emission ◽  
The Brain

Evolution has endowed human race with the most adroit brain, and to harness its potential to the fullest the concept of brain computer interface (BCI) has emerged. One of the most crucial components of BCI is the technique of brain imaging. The first approach in the field of brain imaging was to measure the electrical and magnetic activity of the brain, the techniques being known as Electroencephalography and Magnetoencephalography. Striving for furtherance, researchers came up with another alternative known as Magnetic Resonance Imaging. But it being confined to only structural imaging, the functional aspects of brain were mapped using functional magnetic resonance imaging. A similar but comparatively newer neuroimaging modality is Functional Near Infrared Spectroscopy. Transcranial Magnetic Stimulation neuro-physiological technique is based on the principle of electromagnetic induction. Based on nuclear medicine the brain imaging technologies that are widely explored in the world of BCI are Positron Emission Tomography and Single Positron Emission Tomography.

scholarly journals Imaging of brain oxygenation with magnetic resonance imaging: A validation with positron emission tomography in the healthy and tumoural brain

2016 ◽  
Vol 37 (7) ◽  
pp. 2584-2597 ◽  
Author(s):  
Samuel Valable ◽  
Aurélien Corroyer-Dulmont ◽  
Ararat Chakhoyan ◽  
Lucile Durand ◽  
Jérôme Toutain ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Positron Emission Tomography ◽  
Magnetic Resonance ◽  
High Sensitivity ◽  
Emission Tomography ◽  
Imaging Biomarker ◽  
C6 Glioma Cells ◽  
Resonance Imaging ◽  
Positron Emission ◽  
The Brain

The partial pressure in oxygen remains challenging to map in the brain. Two main strategies exist to obtain surrogate measures of tissue oxygenation: the tissue saturation studied by magnetic resonance imaging (StO2-MRI) and the identification of hypoxia by a positron emission tomography (PET) biomarker with 3-[18F]fluoro-1-(2-nitro-1-imidazolyl)-2-propanol ([18F]-FMISO) as the leading radiopharmaceutical. Nonetheless, a formal validation of StO2-MRI against FMISO-PET has not been performed. The objective of our studies was to compare the two approaches in (a) the normal rat brain when the rats were submitted to hypoxemia; (b) animals implanted with four tumour types differentiated by their oxygenation. Rats were submitted to normoxic and hypoxemic conditions. For the brain tumour experiments, U87-MG, U251-MG, 9L and C6 glioma cells were orthotopically inoculated in rats. For both experiments, StO2-MRI and [18F]-FMISO PET were performed sequentially. Under hypoxemia conditions, StO2-MRI revealed a decrease in oxygen saturation in the brain. Nonetheless, [18F]-FMISO PET, pimonidazole immunohistochemistry and molecular biology were insensitive to hypoxia. Within the context of tumours, StO2-MRI was able to detect hypoxia in the hypoxic models, mimicking [18F]-FMISO PET with high sensitivity/specificity. Altogether, our data clearly support that, in brain pathologies, StO2-MRI could be a robust and specific imaging biomarker to assess hypoxia.

The Similarity of Brain Activity Associated with True and False Recognition Memory Depends On Test Format

1997 ◽  
Vol 8 (3) ◽  
pp. 250-257 ◽  
Author(s):  
Marcia K. Johnson ◽  
Scott F. Nolde ◽  
Mara Mather ◽  
John Kounios ◽  
Daniel L. Schacter ◽  
...  
Keyword(s):  
Source Monitoring ◽  
Brain Activity ◽  
Event Related Potentials ◽  
Emission Tomography ◽  
Test Format ◽  
Test Items ◽  
Positron Emission ◽  
Related Potentials ◽  
False Recognitions ◽  
The Brain

Event-related potentials (ERPs) were compared for correct recognitions of previously presented words and false recognitions of associatively related, nonpresented words (lures) When the test items were presented blocked by test type (old, new, lure), waveforms for old and lure items were different, especially at frontal and left parietal electrode sites, consistent with previous positron emission tomography (PET) data (Schacter, Reiman, et al, 1996) When the test format randomly intermixed the types of items, waveforms for old and lure items were more similar We suggest that test format affects the type of processing subjects engage in, consistent with expectations from the source-monitoring framework (Johnson, Hashtroudi, & Lindsay, 1993) These results also indicate that brain activity as assessed by neuroimaging designs requiring blocked presentation of trials (e.g., PET) do not necessarily reflect the brain activity that occurs in cognitive-behavioral paradigms, in which types of test trials are typically intermixed

scholarly journals THE BIGGEST MYSTERIES OF NATURE — THE UNIVERSE AND THE BRAIN

Osvitolohiya ◽  
2020 ◽  
pp. 6-12
Author(s):  
Blashyak Vladislav
Keyword(s):  
Magnetic Resonance Imaging ◽  
Computed Tomography ◽  
Positron Emission Tomography ◽  
Magnetic Resonance ◽  
Emission Tomography ◽  
Resonance Imaging ◽  
Positron Emission ◽  
The Brain ◽  
The Universe

In the article, which is the result of scientific research in recent decades, the professor points to the value of revolutionary inventions that play a huge role in the development of research, in the evolution of the universe and the brain. One such invention is the telescope. As for the brain, the introduction of research tools such as computed tomography (1972), MRI (magnetic resonance imaging), followed by EEG (electroencephalography), PET (positron emission tomography), MEG (magnetoencephalography) and more recent inventions for tracking of the eyes condition. Such discoveries in science have made the researcher wonder: does knowledge about the brain really allow us to make learning more effective? The scientist provides a classification of children according to their age psychological periods and the work of neurons in the brain. It is indicated that at the age of 4–5 years the network of neurons is best developed. The period of a rebellious teenager is characterized by the maturation of the brain, or the processes of strengthening between neurons. The author speaks about the importance of knowledge in the achievements of neuroeducation in order to understand the strange and most unexpected statements of our students. The article calls for monitoring the results of the latest research on the universe and on our brains. The author is convinced that in the process of teaching educators are able to make certain changes in the brains of their students.

A Review on Brain Imaging Techniques for BCI Applications

2017 ◽  
pp. 300-330 ◽  
Author(s):  
Saugat Bhattacharyya ◽  
Anwesha Khasnobish ◽  
Poulami Ghosh ◽  
Ankita Mazumder ◽  
D. N. Tibarewala
Keyword(s):  
Magnetic Resonance Imaging ◽  
Positron Emission Tomography ◽  
Magnetic Resonance ◽  
Brain Imaging ◽  
Near Infrared ◽  
Emission Tomography ◽  
Resonance Imaging ◽  
Functional Near Infrared Spectroscopy ◽  
Positron Emission ◽  
The Brain

Evolution has endowed human race with the most adroit brain, and to harness its potential to the fullest the concept of brain computer interface (BCI) has emerged. One of the most crucial components of BCI is the technique of brain imaging. The first approach in the field of brain imaging was to measure the electrical and magnetic activity of the brain, the techniques being known as Electroencephalography and Magnetoencephalography. Striving for furtherance, researchers came up with another alternative known as Magnetic Resonance Imaging. But it being confined to only structural imaging, the functional aspects of brain were mapped using functional magnetic resonance imaging. A similar but comparatively newer neuroimaging modality is Functional Near Infrared Spectroscopy. Transcranial Magnetic Stimulation neuro-physiological technique is based on the principle of electromagnetic induction. Based on nuclear medicine the brain imaging technologies that are widely explored in the world of BCI are Positron Emission Tomography and Single Positron Emission Tomography.

1608 The brain activity in go/no-go discrimination task in the monkey studied with positron emission tomography

1996 ◽  
Vol 25 ◽  
pp. S172 ◽  
Author(s):  
Toru Tsujimoto ◽  
Masafumi Ogawa ◽  
Satoru Nishikawa ◽  
Hideo Tsukada ◽  
Takeharu Kakiuchi ◽  
...  
Keyword(s):  
Positron Emission Tomography ◽  
Discrimination Task ◽  
Brain Activity ◽  
Emission Tomography ◽  
Positron Emission ◽  
The Brain

scholarly journals Fibromyalgia: psychiatrists should now be picking up the baton

2011 ◽  
Vol 35 (5) ◽  
pp. 190-191
Author(s):  
Leigh A. Neal
Keyword(s):  
Magnetic Resonance Imaging ◽  
Primary Care ◽  
Positron Emission Tomography ◽  
Pain Perception ◽  
Emission Tomography ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
Positron Emission ◽  
Biological Abnormality ◽  
The Brain

SummaryRecent functional magnetic resonance imaging (fMRI) and positron emission tomography (PET) scan studies have demonstrated the importance of the modulation of pain perception by the emotional regions of the brain in fibromyalgia. In the absence of any other objective biological abnormality, is it time to review the respective roles of primary care, psychiatry and rheumatology in the classification, diagnosis and management of fibromyalgia?

scholarly journals Assessment of Major Depressive Disorders through Neuroimaging Studies and their Treatment Methods

2021 ◽  
Vol 15 ◽  
pp. 18-28
Author(s):  
Jevetha Vijayadasan ◽  
Diksha Raghunathan ◽  
Sivakumar Rajagopal ◽  
Rahul Soangra
Keyword(s):  
Depressive Disorders ◽  
Emission Tomography ◽  
Resonance Imaging ◽  
Major Depressive ◽  
Treatment Methods ◽  
Positron Emission ◽  
Major Depressive Disorders ◽  
Magnetic Resonance Imaging Mri ◽  
The Brain ◽  
Neuroimaging Techniques

Many mental disorders are caused due to improper regulation of the brain and depression is one such. It affects both children and adults and is very common among teenagers. There are many challenges clinicians face regarding the management of this disease. These challenges have prompted the development of various neuroimaging techniques that effectively diagnose the condition. The main techniques are Magnetic resonance imaging (MRI) and Positron emission tomography (PET) which have gained momentum over the years. Advanced MRI techniques help study certain regions of the brain such as hippocampus and amygdala. Effective treatments for depression include antidepressant medications and brain stimulation techniques. Although treatments are effective for a lot of people, there is still room for improvement. This article (1) presents background on depression, its types, symptoms and risk factors; (2) elaborates the neuroimaging techniques used and reviews the various techniques adopted over the years to study depression; and (3) discusses the treatment methods that can be practised to cure depression.

scholarly journals “Air Slicer” for Immersive Visualization of Medical Images

2018 ◽  
Author(s):  
Hossein Dehghani ◽  
Sumit Laha ◽  
Pankaj Kulkarni ◽  
Pradipta Biswas ◽  
Ulas Bagci ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Positron Emission Tomography ◽  
Essential Role ◽  
Emission Tomography ◽  
Therapy Planning ◽  
Resonance Imaging ◽  
Advantages And Disadvantages ◽  
Positron Emission ◽  
Magnetic Resonance Imaging Mri ◽  
Immersive Visualization

Medical imaging plays an essential role in screening, diagnosis, and pre- and intra-procedural intervention and therapy planning. The prime imaging modalities are Ultrasound (US), Computerized Tomography (CT), Positron Emission Tomography (PET), and Magnetic Resonance Imaging (MRI). Each modality has its advantages and disadvantages, thus, an appropriate one is advised by physicians depending on clinical needs.

scholarly journals Brain Activity Associated with Chronic Cancer Pain

2010 ◽  
Vol 5;13 (5;9) ◽  
pp. E342-E342
Author(s):  
Asokumar Buvanendran
Keyword(s):  
Positron Emission Tomography ◽  
Chronic Pain ◽  
Prefrontal Cortex ◽  
Glucose Metabolism ◽  
Severe Pain ◽  
Brain Activity ◽  
Emission Tomography ◽  
Positron Emission ◽  
Affective Pain ◽  
The Brain

Background: The number of neuroimaging studies that examine chronic pain are relatively small, and it is clear that different chronic pain conditions activate diverse regions of the brain. Objective: Cancer patients presenting for diagnostic positron emission tomography (PET) imaging were asked to rate their spontaneous baseline pain score. Twenty patients with either no pain (NRS = 0) or with moderate to severe pain (NRS ≥ 4) were invited to participate in this study to determine the difference in brain activity in cancer patients with moderate to severe chronic pain versus no pain. Study Design: Prospective, non-randomized, observational report. Setting: Academic medical center. Methods: Patients had a 2-D PET scan with the radionuclide 18F-fluoro-2-deoxyglucose (FDG) at a dose of approximately 20 mCi. Each individual raw PET scan was coregistered and normalized to standard stereotactic space. Differences in regional glucose metabolism were then statistically compared between patients with moderate-to-severe pain and patients with no pain. Results: The NRS pain score in the patients with moderate to severe pain (n = 11) was 4.5 [4.0- 6.0] (median[interquartile range]) versus 0.0 [0.0-0.0] (p < 0.001) in the group with no pain (n = 9). Compared to patients with no pain, patients with moderate to severe pain had increased glucose metabolism bilaterally in the prefrontal cortex, BA 9-11. Unilateral activation was found in the right parietal precuneus cortex, BA 7. There were no areas of the brain in which there was decreased activity due to moderate to severe pain. Conclusions: Our results showing a preferential activation of the prefrontal cortex are consistent with results from studies showing that affective pain perception and negative emotions play an important part in the chronic pain experience. Limitations: This was not a randomized clinical trial. Patient medication was not controlled. Key words: chronic pain, cancer pain, positron emission tomography, brain imaging, prefrontal cortex, affective pain, negative emotions

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