|
Brainwave
Neural oscillations, or brainwaves, are rhythmic or repetitive patterns of neural activity in the central nervous system. Neural tissue can generate oscillatory activity in many ways, driven either by mechanisms within individual neurons or by interactions between neurons. In individual neurons, oscillations can appear either as oscillations in membrane potential or as rhythmic patterns of action potentials, which then produce oscillatory activation of post-synaptic neurons. At the level of neural ensembles, synchronized activity of large numbers of neurons can give rise to macroscopic oscillations, which can be observed in an electroencephalogram. Oscillatory activity in groups of neurons generally arises from feedback connections between the neurons that result in the synchronization of their firing patterns. The interaction between neurons can give rise to oscillations at a different frequency than the firing frequency of individual neurons. A well-known example of macrosc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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] |
Hans Berger
Hans Berger (21 May 1873 – 1 June 1941) was a German psychiatrist. He is best known as the inventor of electroencephalography (EEG) in 1924, which is a method used for recording the electrical activity of the brain, commonly described in terms of brainwaves, and as the discoverer of the alpha wave rhythm which is a type of brainwave.Alpha waves have been eponymously referred to as the "Berger wave." Biography Berger was born in Neuses (now part of Coburg), Saxe-Coburg and Gotha, Germany. After attending Casimirianum, where he gained his abitur in 1892, Berger enrolled as a mathematics student at the Friedrich Schiller University of Jena with the intention of becoming an astronomer. After one semester, he abandoned his studies and enlisted for a year of service in the cavalry. During a training exercise, his horse suddenly reared, and he landed in the path of a horse-drawn cannon. The driver of the artillery battery halted the horses in time, leaving the young Berger sh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alpha Waves
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] |
Evoked Potential
An evoked potential or evoked response is an electrical potential in a specific pattern recorded from a specific part of the nervous system, especially the brain, of a human or other animals following presentation of a stimulus such as a light flash or a pure tone. Different types of potentials result from stimuli of different modalities and types. Evoked potential is distinct from spontaneous potentials as detected by electroencephalography (EEG), electromyography (EMG), or other electrophysiologic recording method. Such potentials are useful for electrodiagnosis and monitoring that include detections of disease and drug-related sensory dysfunction and intraoperative monitoring of sensory pathway integrity. Evoked potential amplitudes tend to be low, ranging from less than a microvolt to several microvolts, compared to tens of microvolts for EEG, millivolts for EMG, and often close to 20 millivolts for ECG. To resolve these low-amplitude potentials against the background of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Richard Caton
Richard Caton (1842, Bradford – 1926), of Liverpool, England, was a British physician, physiologist and Lord Mayor of Liverpool who was crucial in discovering the electrical nature of the brain and laid the groundwork for Hans Berger to discover alpha wave activity in the human brain. Early life and education Richard Caton was born in Bradford, son of Richard Caton M.D. and Mary Fawcett. He had a younger sister, Sarah (1846–1872). His father gave up his medical practice through ill health and moved to Scarborough, North Yorkshire, Scarborough where he died. Following this, the family returned to his mother's former home of Halifax. Caton became a boarder at Graham School (Scarborough, England), Scarborough Grammar School where he developed a life-long love of the classics, reflected in later life when he wrote a number of papers on Ancient Greek medicine. Leaving school at sixteen, he worked in the Halifax and Huddersfield Bank but had to leave due to ill health. The medic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adolf Beck (physiologist)
Adolf Abraham Beck (1 January 1863, Kraków – August 1942, Lviv) was a Polish physician and professor of physiology at the University of Lviv. He is considered one of the pioneers of electroencephalography (EEG). Life and career He was born on 1 January 1863, in Kraków, Galicia (Central Europe), Galicia, into a poor Jewish family. During his academic career, Beck supported himself as a tutor, private tutor. Upon graduating with distinction from the gymnasium of his native city in 1884, he entered the Jagiellonian University in Kraków. In 1888, while still a medical student, Beck gained the prize of the university by a paper on the excitability of a nerve, afterward published under the title, "O pobudliwości różnych miejsc tego samego nerwu" (On the Excitability of a Nerve at Different Points). In 1890 he received the degree of Doctor of Medicine, M.D., and in the same year published the results of his extensive research on electrical processes in the brain. His papers ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vladimir Pravdich-Neminsky
Vladimir Pravdich-Neminsky (, ; 2 July 1879 – 17 May 1952) was a Ukrainian physiologist who published the first EEG and the evoked potential of the mammalian brain. He was a representative of Kyiv Physiological School. He was a victim of Soviet repressions. Life Family Vladimir Pravdich-Neminsky was born in Kyiv in Polish-Ukrainian aristocratic family of Neminsky of Prawdzic coat of arms. His father Volodymyr Stanislavovych had a rank of Active State Councillor. He owned 309 dessiatines (approximately 320 hectares or 850 acres) of farmland in Ivashkivtsi village in Podolia Governorate. In the beginning of the 20th century he lent it to local farmers. Little is known of Volodymyr Stanislavovych origin. There was an officer called Stanislav Neminsky (born 1809) in Russian Caucasian army in 1849 but it is unknown whether he is of any relation to Volodymyr. From 1901 to 1911, Volodymyr Stanislavovych worked as an officer in a chancery of Kyiv Land Bank. In 1899, he owned a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Action Potential
An action potential (also known as a nerve impulse or "spike" when in a neuron) is a series of quick changes in voltage across a cell membrane. An action potential occurs when the membrane potential of a specific Cell (biology), cell rapidly rises and falls. This depolarization then causes adjacent locations to similarly depolarize. Action potentials occur in several types of Membrane potential#Cell excitability, excitable cells, which include animal cells like neurons and myocyte, muscle cells, as well as some plant cells. Certain endocrine cells such as pancreatic beta cells, and certain cells of the anterior pituitary gland are also excitable cells. In neurons, action potentials play a central role in cell–cell interaction, cell–cell communication by providing for—or with regard to saltatory conduction, assisting—the propagation of signals along the neuron's axon toward axon terminal, synaptic boutons situated at the ends of an axon; these signals can then connect wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neuroscience
Neuroscience is the scientific study of the nervous system (the brain, spinal cord, and peripheral nervous system), its functions, and its disorders. It is a multidisciplinary science that combines physiology, anatomy, molecular biology, developmental biology, cytology, psychology, physics, computer science, chemistry, medicine, statistics, and mathematical modeling to understand the fundamental and emergent properties of neurons, glia and neural circuits. The understanding of the biological basis of learning, memory, behavior, perception, and consciousness has been described by Eric Kandel as the "epic challenge" of the biological sciences. The scope of neuroscience has broadened over time to include different approaches used to study the nervous system at different scales. The techniques used by neuroscientists have expanded enormously, from molecular and cellular studies of individual neurons to imaging of sensory, motor and cognitive tasks in the brain. Hist ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Local Field Potentials
Local field potentials (LFP) are transient electrical signals generated in nerves and other tissues by the summed and synchronous electrical activity of the individual cells (e.g. neurons) in that tissue. LFP are "extracellular" signals, meaning that they are generated by transient imbalances in ion concentrations in the spaces outside the cells, that result from cellular electrical activity. LFP are 'local' because they are recorded by an electrode placed nearby the generating cells. As a result of the Inverse-square law, such electrodes can only 'see' potentials in a spatially limited radius. They are 'potentials' because they are generated by the voltage that results from charge separation in the extracellular space. They are 'field' because those extracellular charge separations essentially create a local electric field. LFP are typically recorded with a high-impedance microelectrode placed in the midst of the population of cells generating it. They can be recorded, for exam ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frequency
Frequency is the number of occurrences of a repeating event per unit of time. Frequency is an important parameter used in science and engineering to specify the rate of oscillatory and vibratory phenomena, such as mechanical vibrations, audio signals (sound), radio waves, and light. The interval of time between events is called the period. It is the reciprocal of the frequency. For example, if a heart beats at a frequency of 120 times per minute (2 hertz), its period is one half of a second. Special definitions of frequency are used in certain contexts, such as the angular frequency in rotational or cyclical properties, when the rate of angular progress is measured. Spatial frequency is defined for properties that vary or cccur repeatedly in geometry or space. The unit of measurement of frequency in the International System of Units (SI) is the hertz, having the symbol Hz. Definitions and units For cyclical phenomena such as oscillations, waves, or for examp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
