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- Glossary
Olfactory cortex
The olfactory cortex comprises the structures of the cerebrum that are responsible for processing olfactory information. The primary olfactory cortex is the prepiriform cortex, an evolutionarily ancient part of the cortex (paleocortex) with a three-layer structure.
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- Glossary
Oligodendrocytes
Cells of the central nervous system that form the myelin sheath around nerve cells, thereby increasing their conduction velocity. They belong to the glial cells.
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- Glossary
Oligomer
Chemists define an oligomer as a molecule composed of several structurally similar or identical units. Typically, an oligomer consists of a few monomers (e.g., 2–10, occasionally up to about 30). An example from biochemistry is collagen, which is composed of three identical polypeptide chains and occurs as a trimeric protein in connective tissue. If the number of building blocks significantly exceeds this range, as is the case with DNA, it is referred to as a polymer. Oligomers of beta-amyloid may play an important role in the development of Alzheimer's disease.
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- Glossary
Olivary bodies
The olivary bodies are two oval structures in the lower part of the brain stem that contain clusters of nerve cell bodies. The lower olive connects the cerebrum to the cerebellum and plays an important role in controlling motor function. The upper olive is part of the auditory pathway. Its neurons can evaluate differences in transit time and level between the right and left ears, thus helping to determine the direction of sound sources.
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Ontogeny
Development of an individual from a fertilized egg cell to an adult organism.
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- Glossary
Operant conditioning
Operant conditioning refers to the influence of a behavior on display through a result of that behavior, e.g., through immediate reward or immediate punishment. Depending on the outcome, the same behavior or a different behavior will be displayed the next time.
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Operculum
Cortical areas of the frontal, temporal, and parietal lobes at the lateral sulcus. The operculum covers the insular cortex.
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- Glossary
Opsin
Opsins are light-sensitive proteins in the retina that, together with the chromophore retinal, absorb light and convert it into electrical signals. The following opsins occur in humans: rhodopsin in rods, for twilight vision, S-opsin → short-wave cones (blue), M-opsin → medium-wave cones (green), L-opsin → long-wave cones (red). These three cone opsins enable color vision.
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- Glossary
Orbitofrontal cortex
A convolution in the orbitofrontal cortex of the cerebral cortex, located anatomically behind the eyes. The orbitofrontal cortex plays a crucial role in decision-making and monitoring social interactions and is correspondingly complex in structure. It consists of four different substructures: the medial, lateral, anterior, and posterior orbital gyri, as well as the rectus gyrus.
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- Glossary
Place cells
Pyramidal cells in the hippocampus that encode a specific location in a specific environment – for example, a section of a maze. When a test animal is in the center of this area, the cell fires most strongly. Place cells were discovered in 1971 by John O'Keefe and Jonathon Dostrovsky.
