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- Glossary
Mossy fiber
Mossy fibers are nerve fibers that conduct impulses from the spinal cord and the pontine nuclei to the cerebellum. There they terminate in the granule cell layer. The axons of the granule cells of the dentate gyrus in the hippocampus, which extend to CA3, are also referred to as mossy fibers.
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- Glossary
Alzheimer's disease
Alzheimer's disease is a progressive neurodegenerative disorder characterized by cortical atrophy, nerve cell loss, synapse loss, and deposits of amyloid plaques and neurofibrillary tangles, leading to dementia and loss of function. Early symptoms include memory problems, speech disorders, executive deficits, depressive moods, and subtle personality changes. As the disease progresses, global cognitive impairment, aphasia, agnosia, apraxia, and behavioral abnormalities such as apathy, restlessness, and sleep disorders occur. The disease was first described in 1907 by Alois Alzheimer.
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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.
