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Superior colliculus
Superior colliculus A nucleus in the midbrain that coordinate visual, somatic and auditory information adjusting movements of the head and eyes towards a stimulus. contains four types of maps, a visual map, a map of the body surface, a map for sound in space and a motor map. Receives inputs from the retina (via the optic tract), the visual cortex, the somatosensory system and auditory systems. Mediates saccadic eye movements. Is the source of two major descending tracts, the tectospinal tract and the tectopontine tract in addition to regions of the brain stem controlling eye movements.
RELATED TERMS--------------------------------------
Nucleus
Plural: nuclei. The compartment of a cell that contains the chromosomes.
Somatic
Pertaining to the cells and structures of the body, and their function.
Retina
A membrane lining the inside of the back of the eye that contains light-sensitive nerve cells that convert focused light into nerve impulses, making vision possible.
Cortex
The outer layer of the cerebrum, densely packed with nerve cells.
Somatosensory
Refers to sensory signals from all tissues of the body including skin, viscera, muscles, and joints.
Brain
"That part of the central nervous system that is located within the cranium (skull). The brain functions as the primary receiver, organizer and distributor of information for the body. It has two (right and left) halves called ""hemispheres."" "
SIMILAR TERMS--------------------------------------
Superantigen
An antigen that interacts with the T cell receptor in a domain outside of the antigen recognition site. This type of interaction induces the activation of larger numbers of T cells compared to antigens that are presented in the antigen recognition site.
Superego
In psychoanalytic theory, that part of the personality structure associated with ethics, standards, and self-criticism. It is formed by identification with important and esteemed persons in early life, particularly parents. The supposed or actual wishes of these significant persons are taken over as part of the child's own standards to help form the conscience.
Superficial Thrombophlebitis
A clot in a superficial vein, just under the skin.
Superinfection
Sudden growth of a different type of bacteria than the type originally diagnosed and treated. This is a common cause of treatment failure because the new type of bacteria is often resistant to first-line antibiotics.
Superior
The anatomical term for "above". i.e. the head is superior to the shoulder. Typically used in humans only. See Cranial/Caudal/Inferior.
Superior temporal polysensory area (STP)
Area of monkey cortex. Virtually all cells respond to visual stimuli but some also activated by somatosensory and auditory input. Large receptive fields covering most of the visual field with no visuotopic order. Show radial or opponent direction selectivity. Some cells have fields responding to motion either towards the area centralis or away from it. Others show selective responses for object moving in depth, producing either looming or contracting pattern of motion in the field. Seem to be sensitive to information about peripheral optic flow.
Superior vena cava
The large vein that returns blood to the heart from the head and arms.
Superiority trial
A trial with the primary objective of showing that the response to the product is superior to a comparative agent (active or placebo control).
Supernumerary tooth
Extra tooth.
PREVIOUS AND NEXT TERMS--------------------------------------
Size constancy
The fact that the perception of the sizes of objects remains remarkably constant at varying distance despite the fact that the image projected on the retina changes.
Stabilized retinal images
Technique for examining perception without eye movement accompanied by loss of color and contour perception. Demonstrates that movement of an image across the retina is vital for perception.
Stereoscope
Device for creating a 3-D image of a drawn objects. Works by projects two different images of the objects to the eyes.
Stiles-Crawford effect
Light entering the eye through the center of the pupil is more effective than light entering at a peripheral point near the edge of the pupil. This is largely to to the directionally sensitive photoreceptors which are oriented towrad the center of the pupil. This helps to minimize the effect of stray light.
Stimulus equivalence
If the stimulus controlling behavior is a pattern of light on the retina than an infinite number of images are equivalent in their effects.
Superior colliculus
Superior temporal polysensory area (STP)
Area of monkey cortex. Virtually all cells respond to visual stimuli but some also activated by somatosensory and auditory input. Large receptive fields covering most of the visual field with no visuotopic order. Show radial or opponent direction selectivity. Some cells have fields responding to motion either towards the area centralis or away from it. Others show selective responses for object moving in depth, producing either looming or contracting pattern of motion in the field. Seem to be sensitive to information about peripheral optic flow.
Spermatogenesis
Formation of sperm.
Splenomegaly
Enlargement of the spleen.
Sessile polyp
A polyp with a broad base (sessile).
Saponification
The hydrolysis of a fat by alkali with the formation of a soap and glycerol.
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