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- Glossary
Autonomic nervous system
The part of the nervous system that primarily controls unconscious vital functions such as breathing, heartbeat, and blood pressure. The autonomic nervous system is divided into the sympathetic nervous system, which is active in performance and stress situations, and the parasympathetic nervous system, which is active during rest and recovery phases. In some cases, the enteric nervous system, which is responsible for gastrointestinal functions, is also considered part of the autonomic nervous system.
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- Glossary
Axon
The axon is the extension of the nerve cell that is responsible for conducting nerve impulses to the next cell. An axon can branch out many times, reaching a large number of downstream nerve cells. It can be more than a meter long. The axon ends in one or more synapses.
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- Glossary
Basal ganglia
The basal ganglia are a group of subcortical nuclei (located beneath the cerebral cortex) in the telencephalon. The basal ganglia include the globus pallidus and the striatum, and, depending on the author, other structures such as the substantia nigra and the subthalamic nucleus. The basal ganglia are primarily associated with voluntary motor function, but they also influence motivation, learning, and emotion.
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- Glossary
Basilar membrane
The basilar membrane runs through the cochlea for a length of approximately 34 mm. It is stretched like the string of a violin, narrow and stiff at the base and wider and more flexible at the apex. Incoming sound frequencies cause it to vibrate. This movement is picked up by the hair cells in the organ of Corti and converted into nerve impulses.
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Basic emotions
Some theories assume that all emotions can be broken down into a few basic emotions. These are also referred to as primary emotions. According to Ekman, these classically include fear, anger, joy, sadness, disgust, and surprise. Primary emotions arise very quickly in response to an event and sometimes subside just as quickly. Over time, they can transition into secondary emotions (e.g., shame, guilt, or pride).
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Stress disorder
In psychology, stress disorder refers to the pathological reaction to prolonged or short-term extreme stress, such as trauma. A distinction is made between acute stress disorder, also known as a nervous breakdown, and post-traumatic stress disorder. In both cases, the symptoms are the same, although in acute stress disorder they do not last longer than four weeks.
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- Glossary
Beta-amyloid
A peptide consisting of 36 to 42 amino acids that is considered the main component of senile plaques and is believed to be responsible for the development of Alzheimer's disease. The starting product is the amyloid precursor protein (APP). Certain enzymes in the cell membrane cut the precursor protein into peptides of various sizes. Amyloids consisting of 40 and 42 amino acids are found in senile plaques, with the 42-amino-acid product forming aggregates particularly quickly, at least in the Petri dish. The normal function of beta-amyloid has not yet been conclusively clarified.
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- Glossary
Beta waves
Electrical activity of the brain (brain waves) measured on the surface of the head or using electrodes implanted in the brain itself. If the frequency range of the measured activity is between 13 and 30 Hz, these are called beta waves. They are associated with normal waking states and alertness.
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- Glossary
Betz giant cells
Betz giant cells are particularly large pyramidal cells in the primary motor cortex (area 4). They have very large cell bodies with a diameter of 100 µm and heavily myelinated axons that project directly into the spinal cord. This makes them part of the corticospinal neurons of the pyramidal tract. Although they make up only a small portion of the fibers of the pyramidal tract, they are functionally important for the control of voluntary movements, especially fine motor skills.
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- Glossary
Biomarker
In medicine, a biomarker is a substance that provides information about the physiological state of an organism. Biomarkers can either be produced in the body itself or describe chemical compounds that doctors introduce into the body to test certain physiological functions. Several indicators, for example, are being discussed as possible biomarkers for Alzheimer's disease. These include the concentration of soluble amyloid precursor protein in the blood and the activity of the enzyme that cleaves the precursor protein to produce plaque-forming beta-amyloid. Disease-related changes detected by imaging techniques are also often referred to as biomarkers. For example, the breakdown of brain tissue can be detected by MRI.
