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- Glossary
Pyramidal pathway
The pyramidal pathway is a system of axons (long fiber-like extensions of nerve cells) that run from the motor cortex to the spinal cord. 80 percent of all fibers cross to the opposite side in the medulla oblongata. In the medulla, it runs past the pyramids, from which it gets its name. It is involved in fine and voluntary motor skills.
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- Glossary
Pyramidal neurons
Pyramidal neurons are the most common neurons in the cerebral cortex. They are particularly large, and their "three-pointed" cell body resembles a cone or pyramid when viewed in cross-section.
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- Glossary
Spinal paralysis
This is the term used by doctors to describe a combination of symptoms that occur when the nerve cord in the spinal cord is severed. The location of the injury on the spine is decisive for its consequences: the body can no longer control limbs and organs whose innervation branches off from the spinal cord below the damaged area. Possible consequences range from partial paralysis of the limbs to complete loss of control over the rectum and bladder. Also called paraplegia or paraparesis.
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- Glossary
Reissner membrane
This membrane separates the scala media from the scala vestibuli in the cochlea.
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- Glossary
Releasing hormone
Hormones of the hypothalamus that promote the release of other hormones in the adenohypophysis.
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- Glossary
REM sleep
"REM" stands for "rapid eye movement" – and rapid eye movements are also characteristic of REM sleep. During the course of a night, we go through several such REM phases, which are interrupted by non-REM phases. REM sleep is characterized by rapid eye movements, low-amplitude brain activity of mixed frequencies, and reduced muscle tone. Pulse and respiratory rate, on the other hand, are increased. In addition, we dream particularly vividly and intensely during these phases. People who are awakened from REM sleep often report vivid, concrete, and emotional dreams, while those awakened from non-REM sleep tend to report more abstract dreams that resemble thoughts.
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- Glossary
Retinal
A chemical synthesized from vitamin A. Together with opsin, it forms rhodopsin.
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- Glossary
Retrograde amnesia
A form of memory disorder in which memories from before the damage occurred can no longer be retrieved. The affected period can vary greatly and range from just hours before the event to entire decades.
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- Glossary
Receptive field
The receptive field is the area of the environment in which a stimulus changes (increases or decreases) the activity of a specific nerve cell.
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- Glossary
Receptor
A receptor is a protein, usually located in the cell membrane or inside the cell, that recognizes a specific external signal (e.g., a neurotransmitter, hormone, or other ligand) and causes the cell to trigger a defined response. Depending on the type of receptor, this response can be excitatory, inhibitory, or modulatory.
