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- Glossary
Multiple sclerosis
A common neurological disease that predominantly occurs in young adults. For reasons that are still unclear, the body's own cells attack and destroy the myelin sheaths of nerve cells. This can happen throughout the central nervous system, which is why two different multiple sclerosis patients can suffer from very different symptoms. Common symptoms include visual disturbances, numbness in the arms and legs, but also coordination problems, muscle weakness, and bladder problems.
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- Glossary
Myelin
Myelin is a fatty substance produced by glial cells. It envelops the axons (long, fiber-like extensions) of nerve cells and insulates them, preventing messages from passing uncontrollably to neighboring nerve cells. This also greatly accelerates conduction velocity.
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- Glossary
Afterimage
An image that is perceived after the actual image is no longer present. An afterimage normally occurs when you have stared at an image for about a minute. In the case of positive afterimages, the image has similar brightness and colors to the original. Negative afterimages occur more frequently: when looking at a white surface, the image previously viewed appears there in the respective complementary color. Afterimages are caused by the "overfatigue" of the photoreceptors, which stop sending signals to the brain after a certain period of viewing.
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- Glossary
Nose
The olfactory organ of vertebrates. In the nasal cavity, the air is cleaned by cilia, and in the upper area is the olfactory epithelium, which detects odors.
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- Glossary
Sodium-potassium pump
The sodium-potassium pump is a protein in the cell membrane. When energy is consumed, it transports three sodium ions from inside the cell to the external environment and, in return, two potassium ions from the external environment to inside the cell.
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- Glossary
Neglect
Neglect is a perceptual disorder in which parts of the body or stimuli are ignored due to a brain lesion. The disorder affects the sides opposite the brain lesion. It usually occurs after lesions in the right parietal lobe. Accordingly, visual, auditory, and somatosensory stimuli on the left side are ignored.
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Neocortex
The neocortex is the phylogenetically youngest part of the cerebral cortex. Since it is structured relatively uniformly in six layers, it is also referred to as the isocortex.
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Retina
The retina is the inner layer of the eye covered with pigment epithelium. The retina is characterized by an inverse (reversed) arrangement: light must first pass through several layers before it hits the photoreceptors (cones and rods). The signals from the photoreceptors are transmitted via the optic nerve to the processing areas of the brain. The reason for the inverse arrangement is the evolutionary development of the retina, which is a protrusion of the brain.The retina is approximately 0.2 to 0.5 mm thick.
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- Glossary
Neurodegeneration
Collective term for diseases in which nerve cells gradually lose their structure or function until they eventually die. In many cases, misfolded proteins are the trigger – such as certain forms of the proteins beta-amyloid and tau in the case of Alzheimer's disease. In other diseases, such as Parkinson's disease or Huntington's disease, proteins within the neurons are not broken down properly. As a result, toxic aggregates are deposited there, leading to the respective disease symptoms. While Huntington's disease is clearly genetic, in Parkinson's and Alzheimer's there appear to be certain gene variants that promote their development. None of these neurodegenerative diseases can be cured at present.
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- Glossary
Neuroenhancement
Neuroenhancement is about improving cognitive performance. To this end, drugs used to treat dementia, hyperactivity, or narcolepsy are taken by healthy individuals with the aim of improving their learning abilities, increasing their alertness, or staying awake and active for longer. In addition to the ethical questions this raises, there is also medical controversy as to whether this self-medication actually works and what the long-term consequences might be.
