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Electroencephalography
Electroencephalography (EEG) is a method to record an electrogram of the spontaneous electrical activity of the brain. The biosignal, bio signals detected by EEG have been shown to represent the postsynaptic potentials of pyramidal neurons in the neocortex and allocortex. It is typically non-invasive, with the EEG electrodes placed along the scalp (commonly called "scalp EEG") using the 10–20 system (EEG), International 10–20 system, or variations of it. Electrocorticography, involving surgical placement of electrodes, is sometimes called Electrocorticography, "intracranial EEG". Clinical interpretation of EEG recordings is most often performed by visual inspection of the tracing or quantitative EEG, quantitative EEG analysis. Voltage fluctuations measured by the EEG bioamplifier, bio amplifier and electrodes allow the evaluation of normal Brain activity and meditation, brain activity. As the electrical activity monitored by EEG originates in neurons in the underlying Huma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alpha Wave
Alpha waves, or the alpha rhythm, are neural oscillations in the frequency range of 8–12 Hz likely originating from the synchronous and coherent ( in phase or constructive) neocortical neuronal electrical activity possibly involving thalamic pacemaker cells. Historically, they are also called "Berger's waves" after Hans Berger, who first described them when he invented the EEG in 1924. Alpha waves are one type of brain waves detected by electrophysiological methods, e.g., electroencephalography (EEG) or magnetoencephalography (MEG), and can be quantified using power spectra and time-frequency representations of power like quantitative electroencephalography (qEEG). They are predominantly recorded over parieto-occipital brain and were the earliest brain rhythm recorded in humans. Alpha waves can be observed during relaxed wakefulness, especially when there is no mental activity. During the eyes-closed condition, alpha waves are prominent at parietal locations. Atte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrocorticography
Electrocorticography (ECoG), a type of intracranial electroencephalography (iEEG), is a type of electrophysiological monitoring that uses electrodes placed directly on the exposed surface of the brain to record electrical activity from the cerebral cortex. In contrast, conventional electroencephalography (EEG) electrodes monitor this activity from outside the skull. ECoG may be performed either in the operating room during surgery (intraoperative ECoG) or outside of surgery (extraoperative ECoG). Because a craniotomy (a surgical incision into the skull) is required to implant the electrode grid, ECoG is an invasive procedure. History ECoG was pioneered in the early 1950s by Wilder Penfield and Herbert Jasper, neurosurgeons at the Montreal Neurological Institute. The two developed ECoG as part of their groundbreakinMontreal procedure a surgical protocol used to treat patients with severe epilepsy. The cortical potentials recorded by ECoG were used to identify epileptogen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epilepsy
Epilepsy is a group of Non-communicable disease, non-communicable Neurological disorder, neurological disorders characterized by a tendency for recurrent, unprovoked Seizure, seizures. A seizure is a sudden burst of abnormal electrical activity in the brain that can cause a variety of symptoms, ranging from brief lapses of awareness or muscle jerks to prolonged convulsions. These episodes can result in physical injuries, either directly, such as broken bones, or through causing accidents. The diagnosis of epilepsy typically requires at least two unprovoked seizures occurring more than 24 hours apart. In some cases, however, it may be diagnosed after a single unprovoked seizure if clinical evidence suggests a high risk of recurrence. Isolated seizures that occur without recurrence risk or are provoked by identifiable causes are not considered indicative of epilepsy. The underlying cause is often unknown, but epilepsy can result from brain injury, stroke, infections, Brain tumor, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quantitative EEG
Quantitative electroencephalography (qEEG or QEEG) is a field concerned with the numerical analysis of electroencephalography (EEG) data and associated behavioral correlates. Details Techniques used in digital signal analysis are extended to the analysis of electroencephalography (EEG). These include wavelet analysis and Fourier analysis, with new focus on shared activity between rhythms including phase synchrony (coherence, phase lag) and magnitude synchrony (comodulation/correlation, and asymmetry). The analog signal comprises a microvoltage time series of the EEG, sampled digitally and sampling rates adequate to over-sample the signal (using the Nyquist principle of exceeding twice the highest frequency being detected). Modern EEG amplifiers use adequate sampling to resolve the EEG across the traditional medical band from DC to 70 or 100 Hz, using sample rates of 250/256, 500/512, to over 1000 samples per second, depending on the intended application. QEEG can be p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Human Brain
The human brain is the central organ (anatomy), organ of the nervous system, and with the spinal cord, comprises the central nervous system. It consists of the cerebrum, the brainstem and the cerebellum. The brain controls most of the activities of the human body, body, processing, integrating, and coordinating the information it receives from the sensory nervous system. The brain integrates sensory information and coordinates instructions sent to the rest of the body. The cerebrum, the largest part of the human brain, consists of two cerebral hemispheres. Each hemisphere has an inner core composed of white matter, and an outer surface – the cerebral cortex – composed of grey matter. The cortex has an outer layer, the neocortex, and an inner allocortex. The neocortex is made up of six Cerebral cortex#Layers of neocortex, neuronal layers, while the allocortex has three or four. Each hemisphere is divided into four lobes of the brain, lobes – the frontal lobe, frontal, pa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brain
The brain is an organ (biology), organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It consists of nervous tissue and is typically located in the head (cephalization), usually near organs for special senses such as visual perception, vision, hearing, and olfaction. Being the most specialized organ, it is responsible for receiving information from the sensory nervous system, processing that information (thought, cognition, and intelligence) and the coordination of motor control (muscle activity and endocrine system). While invertebrate brains arise from paired segmental ganglia (each of which is only responsible for the respective segmentation (biology), body segment) of the ventral nerve cord, vertebrate brains develop axially from the midline dorsal nerve cord as a brain vesicle, vesicular enlargement at the rostral (anatomical term), rostral end of the neural tube, with centralized control over all body segments. All vertebr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
10–20 System (EEG)
The 10–20 system or International 10–20 system is an internationally recognized method to describe and apply the location of scalp electrodes in the context of an EEG exam, polysomnograph sleep study, or voluntary lab research. This method was developed to maintain standardized testing methods ensuring that a subject's study outcomes (clinical or research) could be compiled, reproduced, and effectively analyzed and compared using the scientific method. The system is based on the relationship between the location of an electrode and the underlying area of the brain, specifically the cerebral cortex. Across all phases of consciousness, brains produce different, objectively recognizable and distinguishable electrical patterns, which can be detected by electrodes on the skin. These patterns vary, and are affected by multiple extrinsic factors, including age, prescription drugs, somatic diagnoses, Medical history, history of neurologic insults/injury/trauma, and substance abuse. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beta Wave
Beta waves, or beta rhythm, are neural oscillations (brainwaves) in the brain with a frequency range of between 12.5 and 30 Hz (12.5 to 30 cycles per second). Several different rhythms coexist, with some being inhibitory and others excitory in function. Beta waves can be split into three sections: Low Beta Waves (12.5–16 Hz, "Beta 1"); Beta Waves (16.5–20 Hz, "Beta 2"); and High Beta Waves (20.5–28 Hz, "Beta 3"). Beta states are the states associated with normal waking consciousness. History Beta waves were discovered and named by the German psychiatrist Hans Berger, who invented electroencephalography (EEG) in 1924, as a method of recording electrical brain activity from the human scalp. Berger termed the larger amplitude, slower frequency waves that appeared over the posterior scalp when the subject's eye were closed alpha waves. The smaller amplitude, faster frequency waves that replaced alpha waves when the subject opened their eye ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrode
An electrode is an electrical conductor used to make contact with a nonmetallic part of a circuit (e.g. a semiconductor, an electrolyte, a vacuum or a gas). In electrochemical cells, electrodes are essential parts that can consist of a variety of materials (chemicals) depending on the type of cell. An electrode may be called either a cathode or anode according to the direction of the electric current, unrelated to the potential difference between electrodes. Michael Faraday coined the term "" in 1833; the word recalls the Greek ἤλεκτρον (, "amber") and ὁδός (, "path, way"). The electrophore, invented by Johan Wilcke in 1762, was an early version of an electrode used to study static electricity. Anode and cathode in electrochemical cells Electrodes are an essential part of any battery. The first electrochemical battery was devised by Alessandro Volta and was aptly named the Voltaic cell. This battery consisted of a stack of copper and zinc electrodes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lobes Of The Brain
The lobes of the brain are the four major identifiable regions of the human cerebral cortex, and they comprise the surface of each hemisphere of the cerebrum. The two hemispheres are roughly symmetrical in structure, and are connected by the corpus callosum. Some sources include the insula and limbic lobe but the limbic lobe incorporates parts of the other lobes. The lobes are large areas that are anatomically distinguishable, and are also functionally distinct. Each lobe of the brain has numerous ridges, or gyri, and furrows, sulci that constitute further subzones of the cortex. The expression "lobes of the brain" usually refers only to those of the cerebrum, not to the distinct areas of the cerebellum. Frontal lobe The frontal lobe is located at the front of each cerebral hemisphere and positioned in front of the parietal lobe and above and in front of the temporal lobe. It is separated from the parietal lobe by a space between tissues called the central sulcus, and from ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mental Activity
Energy is a concept in some psychological theories or models of a postulated unconscious mental functioning on a level between biology and consciousness. Philosophical accounts The idea harks back to Aristotle's conception of '' actus et potentia''. In the philosophical context, the term "energy" may have the literal meaning of "activity" or "operation". Henry More, in his 1642 ''Psychodia platonica; or a platonicall song of the soul'', defined an "energy of the soul" as including "every phantasm of the soul". In 1944 Julian Sorell Huxley characterised "mental energy" as "the driving forces of the psyche, emotional as well as intellectual .." Psychoanalytic accounts In 1874, the concept of " psychodynamics" was proposed with the publication of ''Lectures on Physiology'' by German physiologist Ernst Wilhelm von Brücke who, in coordination with physicist Hermann von Helmholtz, one of the formulators of the first law of thermodynamics ( conservation of energy), supposed that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrogram
An electrogram (EGM) is a recording of electrical activity of organs such as the brain and heart, measured by monitoring changes in electric potential. Historically, it also referred to an instrument to measure atmospheric electrical potential. Brain Electroencephalography (EEG) An electroencephalogram (EEG) is an electrical recording of the activity of the brain taken from the scalp. An EEG can be used to diagnose seizures, sleep disorders, and for monitoring of level of anesthesia during surgery. Electrocorticography (ECoG or iEEG) An electrocorticogram is an electrical recording of the brain measured intracranially, that is, from within the brain. Eye Electrooculography (EOG) An electrooculogram (EOG) is an electrical recording of the potential between the cornea and the retina, and does not change with visual stimuli. An EOG can measure movements of the eyes and can help in diagnosis of nystagmus. Electroretinography (ERG) An electroretinogram (ERG) is an elec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
