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- Glossary
Parkinson's disease
Parkinson's disease is one of the most common neurological disorders, caused by the death of dopamine-producing neurons in the substantia nigra, leading to a neurotransmitter imbalance in the basal ganglia. Symptoms usually begin late in life with mild tremors (resting tremor), increasing stiffness of the limbs, and slowed voluntary movements (bradykinesia). Later, postural instability, balance disorders, and difficulty walking occur. Other typical features include rigid facial expressions (hypomimia), a shuffling gait, and muscle stiffness (rigor). The disease is incurable, but its symptoms can be treated with medication (e.g., L-dopa, dopamine agonists) or surgery involving deep brain stimulation (brain pacemaker).
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- Glossary
Morphine
Depending on the dose, morphine is either a potent painkiller or a mind-altering drug. Synthesized from poppy seeds and named after the Greek god of dreams, morphine binds to the opioid receptors in the brain.
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- Glossary
Motivation
A motive is a reason. When this motive takes effect, the living being feels motivation – it strives to satisfy its need. For example, for food, protection, or reproduction. Motivation can be intrinsic (from within, e.g., curiosity) or extrinsic (from outside, e.g., reward).
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- Glossary
Motor neuron
Neurons that extend from the central nervous system to the muscles and control their activity.
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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.
