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Signal Enhancement By Extravascular Water Protons
Signal enhancement by extravascular water protons, or SEEP, is a contrast mechanism for functional magnetic resonance imaging (fMRI), which is an alternative to the more commonly employed BOLD (blood-oxygen-level dependent) contrast. This mechanism for image contrast changes corresponding to changes in neuronal activity was first proposed by Dr. Patrick Stroman in 2001. SEEP contrast is based on changes in tissue water content which arise from the increased production of extracellular fluid and swelling of neurons and glial cells at sites of neuronal activity. Because the dominant sources of magnetic resonance imaging, MRI signal in biological tissues are water and lipids, an increase in tissue water content is reflected by a local increase in magnetic resonance imaging, MR signal intensity. A correspondence between BOLD and SEEP signal changes, and sites of activity, has been observed in the brain and appears to arise from the common dependence on changes in local blood flow to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Functional Magnetic Resonance Imaging
Functional magnetic resonance imaging or functional MRI (fMRI) measures brain activity by detecting changes associated with blood flow. This technique relies on the fact that cerebral blood flow and neuronal activation are coupled. When an area of the brain is in use, blood flow to that region also increases. The primary form of fMRI uses the blood-oxygen-level dependent (BOLD) contrast, discovered by Seiji Ogawa in 1990. This is a type of specialized brain and body scan used to map neuron, neural activity in the brain or spinal cord of humans or other animals by imaging the change in blood flow (hemodynamic response) related to energy use by brain cells. Since the early 1990s, fMRI has come to dominate brain mapping research because it does not involve the use of injections, surgery, the ingestion of substances, or exposure to ionizing radiation. This measure is frequently corrupted by noise from various sources; hence, statistical procedures are used to extract the underlying si ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blood-oxygen-level Dependent
Blood-oxygen-level-dependent imaging, or BOLD-contrast imaging, is a method used in functional magnetic resonance imaging (fMRI) to observe different areas of the brain or other organs, which are found to be active at any given time. Theory Neurons do not have internal reserves of energy in the form of sugar and oxygen, so their firing causes a need for more energy to be brought in quickly. Through a process called the haemodynamic response, blood releases oxygen to active neurons at a greater rate than to inactive neurons. This causes a change of the relative levels of oxyhemoglobin and deoxyhemoglobin (oxygenated or deoxygenated blood) that can be detected on the basis of their differential magnetic susceptibility. In 1990, three papers published by Seiji Ogawa and colleagues showed that hemoglobin has different magnetic properties in its oxygenated and deoxygenated forms (deoxygenated hemoglobin is paramagnetic and oxygenated hemoglobin is diamagnetic), both of which co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Extracellular Fluid
In cell biology, extracellular fluid (ECF) denotes all body fluid outside the cells of any multicellular organism. Total body water in healthy adults is about 60% (range 45 to 75%) of total body weight; women and the obese typically have a lower percentage than lean men. Extracellular fluid makes up about one-third of body fluid, the remaining two-thirds is intracellular fluid within cells. The main component of the extracellular fluid is the interstitial fluid that surrounds cells. Extracellular fluid is the internal environment of all multicellular animals, and in those animals with a blood circulatory system, a proportion of this fluid is blood plasma. Plasma and interstitial fluid are the two components that make up at least 97% of the ECF. Lymph makes up a small percentage of the interstitial fluid. The remaining small portion of the ECF includes the transcellular fluid (about 2.5%). The ECF can also be seen as having two components – plasma and lymph as a delivery system ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neuron
A neuron, neurone, or nerve cell is an electrically excitable cell that communicates with other cells via specialized connections called synapses. The neuron is the main component of nervous tissue in all animals except sponges and placozoa. Non-animals like plants and fungi do not have nerve cells. Neurons are typically classified into three types based on their function. Sensory neurons respond to stimuli such as touch, sound, or light that affect the cells of the sensory organs, and they send signals to the spinal cord or brain. Motor neurons receive signals from the brain and spinal cord to control everything from muscle contractions to glandular output. Interneurons connect neurons to other neurons within the same region of the brain or spinal cord. When multiple neurons are connected together, they form what is called a neural circuit. A typical neuron consists of a cell body (soma), dendrites, and a single axon. The soma is a compact structure, and the axon and dend ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glial Cell
Glia, also called glial cells (gliocytes) or neuroglia, are non-neuronal cells in the central nervous system (brain and spinal cord) and the peripheral nervous system that do not produce electrical impulses. They maintain homeostasis, form myelin in the peripheral nervous system, and provide support and protection for neurons. In the central nervous system, glial cells include oligodendrocytes, astrocytes, ependymal cells, and microglia, and in the peripheral nervous system they include Schwann cells and satellite cells. Function They have four main functions: *to surround neurons and hold them in place *to supply nutrients and oxygen to neurons *to insulate one neuron from another *to destroy pathogens and remove dead neurons. They also play a role in neurotransmission and synaptic connections, and in physiological processes such as breathing. While glia were thought to outnumber neurons by a ratio of 10:1, recent studies using newer methods and reappraisal of historical quant ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnetic Resonance Imaging
Magnetic resonance imaging (MRI) is a medical imaging technique used in radiology to form pictures of the anatomy and the physiological processes of the body. MRI scanners use strong magnetic fields, magnetic field gradients, and radio waves to generate images of the organs in the body. MRI does not involve X-rays or the use of ionizing radiation, which distinguishes it from CT and PET scans. MRI is a medical application of nuclear magnetic resonance (NMR) which can also be used for imaging in other NMR applications, such as NMR spectroscopy. MRI is widely used in hospitals and clinics for medical diagnosis, staging and follow-up of disease. Compared to CT, MRI provides better contrast in images of soft-tissues, e.g. in the brain or abdomen. However, it may be perceived as less comfortable by patients, due to the usually longer and louder measurements with the subject in a long, confining tube, though "Open" MRI designs mostly relieve this. Additionally, implants and oth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnetic Susceptibility
In electromagnetism, the magnetic susceptibility (Latin: , "receptive"; denoted ) is a measure of how much a material will become magnetized in an applied magnetic field. It is the ratio of magnetization (magnetic moment per unit volume) to the applied magnetizing field intensity . This allows a simple classification, into two categories, of most materials' responses to an applied magnetic field: an alignment with the magnetic field, , called paramagnetism, or an alignment against the field, , called diamagnetism. Magnetic susceptibility indicates whether a material is attracted into or repelled out of a magnetic field. Paramagnetic materials align with the applied field and are attracted to regions of greater magnetic field. Diamagnetic materials are anti-aligned and are pushed away, toward regions of lower magnetic fields. On top of the applied field, the magnetization of the material adds its own magnetic field, causing the field lines to concentrate in paramagnetism, or be excl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spinal FMRI
Functional magnetic resonance imaging (fMRI) of the spinal cord (spinal fMRI) is an adaptation of the fMRI method that has been developed for use in the brain. Although the basic principles underlying the methods are the same, spinal fMRI requires a number of specific adaptations to accommodate the periodic motion of the spinal cord, the small cross-sectional dimensions (roughly 8 mm × 15 mm at the largest region) and length (~45 cm in adult humans) of the spinal cord, and the fact that the magnetic field that is used for MRI varies with position in the spinal cord because of magnetic susceptibility differences between bone and tissues. Spinal fMRI has been used to produce maps of neuronal activity at most levels of the spinal cord in response to various stimuli, such as touch, vibration, and thermal changes, and with motor tasks. Research applications of spinal fMRI to date include studies of normal sensory and motor function, and studies of the effects of trauma a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
In-vivo
Studies that are ''in vivo'' (Latin for "within the living"; often not italicized in English) are those in which the effects of various biological entities are tested on whole, living organisms or cells, usually animals, including humans, and plants, as opposed to a tissue extract or dead organism. This is not to be confused with experiments done ''in vitro'' ("within the glass"), i.e., in a laboratory environment using test tubes, Petri dishes, etc. Examples of investigations ''in vivo'' include: the pathogenesis of disease by comparing the effects of bacterial infection with the effects of purified bacterial toxins; the development of non-antibiotics, antiviral drugs, and new drugs generally; and new surgical procedures. Consequently, animal testing and clinical trials are major elements of ''in vivo'' research. ''In vivo'' testing is often employed over ''in vitro'' because it is better suited for observing the overall effects of an experiment on a living subject. In drug d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magn Reson Med
''Magnetic Resonance in Medicine'' is a monthly peer-reviewed medical journal covering research on all aspects of the development and use of nuclear magnetic resonance and electron paramagnetic resonance techniques for medical applications. It was established in 1984 and is published by Wiley Wiley may refer to: Locations * Wiley, Colorado, a U.S. town * Wiley, Pleasants County, West Virginia, U.S. * Wiley-Kaserne, a district of the city of Neu-Ulm, Germany People * Wiley (musician), British grime MC, rapper, and producer * Wiley Mil ... on behalf of thInternational Society for Magnetic Resonance in Medicine External links *{{Official website, http://onlinelibrary.wiley.com/journal/10.1002/(ISSN)1522-2594 Medical physics journals Monthly journals Wiley-Blackwell academic journals English-language journals Publications established in 1984 Radiology and medical imaging journals ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
J Cereb Blood Flow Metab
The ''Journal of Cerebral Blood Flow & Metabolism'' is a monthly peer-reviewed medical journal the official journal of the International Society for Cerebral Blood Flow & Metabolism and publishes peer-reviewed research and review papers. covering research on experimental, theoretical, and clinical aspects of brain circulation, metabolism and imaging. The editor-in-chief is Jun Chen (University of Pittsburgh). According to the ''Journal Citation Reports'', the journal has a 2020 impact factor The impact factor (IF) or journal impact factor (JIF) of an academic journal is a scientometric index calculated by Clarivate that reflects the yearly mean number of citations of articles published in the last two years in a given journal, as i ... of 6.200. References External links * International Society for Cerebral Blood Flow & Metabolism Neuroscience journals Publications established in 1981 Nature Research academic journals English-language journals Monthly journals Delayed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NeuroImage
''NeuroImage'' is a peer-reviewed scientific journal covering research on neuroimaging, including functional neuroimaging and functional human brain mapping. The current Editor in Chief is Michael Breakspear. Abstracts from the annual meeting of the Organization for Human Brain Mapping have been published as supplements to the journal. Members of the Organization for Human Brain Mapping are eligible for reduced subscription rates. In 2012, Elsevier launched an online-only, open access sister journal to ''NeuroImage'', entitled '' NeuroImage: Clinical''. Among prolific authors publishing numerous articles in the journal are Karl J. Friston, Arthur W. Toga, Paul M. Thompson and Karl Zilles. Related journals are Human Brain Mapping, Frontiers in Human Neuroscience, Cerebral Cortex, Magnetic Resonance in Medicine, Journal of Neuroscience and Journal of Cognitive Neuroscience. Abstracting and indexing The journal is abstracted and indexed in Scopus, Science Citation Index, Curre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
