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- Glossary
Astrocyte
Astrocytes are among the largest glial cells. Their tasks include maintaining the blood-brain barrier and reabsorbing released neurotransmitters (messenger substances in the brain).
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- Glossary
Ataxia
A medical umbrella term for the disturbance or loss of coordination of movement. In the case of target ataxia, for example, a targeted grasp of an object may be slow, shaky, or too fast. Ataxia can be congenital or the result of lesions or degeneration.
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- Glossary
Auditory cortex
The auditory cortex is a part of the temporal lobe that is involved in processing acoustic signals. It is divided into the primary and secondary auditory cortex.
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- Glossary
Attention
Attention serves as a tool for consciously perceiving internal and external stimuli. We achieve this by focusing our mental resources on a limited number of stimuli or pieces of information. While some stimuli automatically attract our attention, we can select others in a controlled manner. The brain also unconsciously processes stimuli that are not currently the focus of our attention.
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- Glossary
Eye
The eye is the sensory organ responsible for perceiving light stimuli – electromagnetic radiation within a specific frequency range. The light visible to humans lies in the range between 380 and 780 nanometers.
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- Glossary
Eyeball layers
The layers of the eye form the wall of the eyeball. They can be roughly divided into three areas: the outer membrane with the cornea and sclera, the middle membrane with the iris, choroid, and ciliary body, and the inner membrane with the photoreceptive and blind parts of the retina.
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- Glossary
Outer hair cell
Outer and inner hair cells are sensory cells for acoustic signals in the organ of Corti. At their tips, they have hair-like projections called stereocilia, which are connected to each other and, in the case of the outer hair cells, also to the tectorial membrane. The three rows of outer hair cells filter acoustic signals and act as a cochlear amplifier: without them, our hearing sensitivity would be reduced by about 50 dB.
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- Glossary
Autism
A serious developmental disorder that often manifests itself in reduced social skills, impaired communication, and stereotypical behavior. Today, it is understood to be part of the autism spectrum disorders.
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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.
