|
 |
||
 |
| This glossary contains: 19186 medical terms |
 |
Contrast sensitivity function
|
|
Contrast sensitivity function The reciprocal of the threshold contrast required to obtain a criterion response from a cell or a human subject as a function of spatial frequency. Falls off in sensitivity as the spatial frequency of the test pattern increases.
RELATED TERMS--------------------------------------
Contrast
"Short for ""contrast media."" Contrast media are X-ray dyes used to provide contrast, for example, between blood vessels and other tissue."
Cell
Fundamental structural unit of all life. The cell consists primarily of an outer plasma membrane, which separates it from the environment; the genetic material (DNA), which encodes heritable information for the maintainance of life; and the cytoplasm, a heterogeneous assemblage of ions, molecules, and fluid.
Sensitivity
1. The reciprocal of the minimum stimulus strength required for the stimulus to be detected reliably (1/threshold) May be related to noise and other mechanisms. 2. Physiologically measured sensitivity averaged over many stimulus/response cycles. A measure of gain. Noise free.
SIMILAR TERMS--------------------------------------
Contac
Contac is a prescription or over-the-counter drug which is (or once was) approved in the United States and possibly in other countries. Active ingredient(s): chlorpheniramine maleate; phenylpropanolamine hydrochloride.
Contac 12 hour
Contac 12 hour is a prescription or over-the-counter drug which is (or once was) approved in the United States and possibly in other countries. Active ingredient(s): chlorpheniramine maleate; phenylpropanolamine hydrochloride.
Contact dermatitis
A rash or an inflammation of the skin caused by contact with various substances.
Contact dermatitis, allergic
Also called allergic contact eczema, this is a red, itchy, weepy reaction where the skin has come into contact with a substance that the immune system recognizes as foreign, such as poison ivy or certain preservatives in creams and lotions.
Contact eczema
A localized reaction that includes redness, itching, and burning where the skin has come into contact with an allergen (an allergy-causing substance) or with an irritant such as an acid, a cleaning agent or another chemical.
Contact eczema, allergic
Also called allergic contact dermatitis, this is a red, itchy, weepy reaction where the skin has come into contact with a substance that the immune system recognizes as foreign, such as poison ivy or certain preservatives in creams and lotions.
Contact healing
Another name for the alternative medicine practice of laying on of hands.
Contagious
Easily transmitted by direct or indirect contact.
Content validity
The extent to which a variable (for example, a rating scale) measures what it is supposed to measure (for example, self-care ability).
Contig
Contiguous sequence of DNA created by assembling overlapping sequenced fragments of a chromosome. A group of clones representing overlapping regions of the genome.
Contig map
A map depicting the relative order of a linked library of small overlapping clones representing a complete chromosome segment.
Contiguous gene syndrome
A disorder due to deletion of multiple gene loci that are adjacent to one another. Contiguous gene syndromes are characterized by multiple, apparently unrelated, clinical features caused by deletion of the multiple adjacent genes. Each of the individual genes within a contiguous region, when mutated, gives rise to a distinct feature.
Continence
The ability to hold in a bowel movement or urine.
Continent ileostomy
An operation to create a pouch from part of the small intestine. Stool that collects in the pouch is removed by inserting a small tube through an opening made in the abdomen.
Contingency reinforcement
In operant or instrumental conditioning, ensuring that desired behavior is followed by positive consequences and that undesired behavior is not rewarded.
Continuous passive motion machine
A machine used to help rehabilitate a limb (an arm or leg).
Contra Costa Regional Medical Center
The Contra Costa Regional Medical Center is a hospital in Contra Costa, California, United States.
Contraception
The intentional prevention of conception or impregnation. Also called birth control.
Contraceptive device, intrauterine (IUD)
A device inserted into the uterus (womb) to prevent conception (pregnancy). The IUD can be a coil, loop, triangle, or T in shape made of plastic or metal.
Contraceptive sponge, vaginal
A contraceptive device that is donut-shaped, made of plastic, contains a spermicide (nonoxynol-9) and is inserted into the vagina to cover the cervix. A loop is provided to ease removal.
Contraceptive, combined oral
"Commonly called ""the pill,"" combined oral contraceptives are the most commonly used form of reversible birth control in the United States. This form of birth control suppresses ovulation (the monthly release of an egg from the ovaries) by the combined actions of the hormones estrogen and progestin."
Contraceptive, diaphragm
A barrier method of contraception that is available by prescription only and must be sized by a health professional to achieve a proper fit.
Contraceptive, minipill
"A form of oral contraceptive taken daily, like combined oral contraceptives (the ""pill""), but containing only the hormone progestin and no estrogen. "
Contraceptive, pill
"Commonly called ""the pill,"" combined oral contraceptives are the most commonly used form of reversible birth control. This form of birth control suppresses ovulation (the monthly release of an egg from the ovaries) by the combined actions of the hormones estrogen and progestin."
Contract
A written, dated, and signed agreement between two or more involved parties that sets out any arrangements on delegation and distribution of tasks and obligations and, if appropriate, on financial matters. The protocol may serve as the basis of a contract.
Contraction
During labor, the strong, rhythmic tightening of the uterus. Pre-laborcontractions are usually irregular and don't increase in intensity orduration.
Contraction, uterine
"The tightening and shortening of the uterine muscles. During labor, contractions accomplish two things: (1) they cause the cervix to thin and dilate (open); and (2) they aid the baby to descend into the birth canal."
Contractions, Braxton Hicks
Irregular contractions of the womb (the uterus) occurring towards the middle of pregnancy in the first pregnancy and, earlier and more intensely, in subsequent pregnancies.
Contracture
Deformity caused by abnormal shortening of the muscles.
Contraindicate
To make a treatment or procedure inadvisable because of a particular condition or circumstance. For examples, certain medications are contraindicated during pregnancy because of the danger they pose to the fetus and the use of aspirin is clearly contraindicated in small children because of the danger of Reye syndrome.
Contraindication
A condition that makes a treatment not helpful or even harmful.
Contralateral
Affecting or pertaining to the opposite side.
Contrast
"Short for ""contrast media."" Contrast media are X-ray dyes used to provide contrast, for example, between blood vessels and other tissue."
Contrast media
"X-ray dye. Commonly spoken of as ""contrast."""
Contrast medium
A substance used in x-ray studies to aid in showing internal structures.
Contrast nephropathy
A form of acute renal failure that starts soon after administration of contrast media (dye) for X-rays. The disorder usually runs a benign course and only rarely requires recourse to dialysis.
Contrast sensitivity, visual
The ability to perceive differences between an object and its background.
Control (genetic)
The control of gene expression. Genetic control may be on the transcriptional or translational level. Transcriptional control works by controlling the number of RNA transcripts of a region of DNA, indirectly controlling protein synthesis. Translational control of protein synthesis works by regulating the step of translating RNA into protein.
Control (research)
In research, control subjects or control procedures permit comparison with experimental results.
Control group
The group of subjects in a controlled study that receives no treatment, a standard treatment, or a placebo instead of the therapy being investigated.
Controllable disease
disease or illness that can't be cured but can be managed with diet, exercise, or medications.
Controlled Disease
Taking care of oneself so that a disease has less of an effect on the body. People with diabetes can "control" the disease by staying on their diets, by exercising, by taking medicine if it is needed, and by monitoring their blood glucose. This care will help keep the glucose (sugar) level in the blood from becoming either too high or too low.
Controlled study
A study in which a test treatment is compared with a treatment that has known effects. The control group may receive no treatment, standard treatment, or placebo.
Contusion
A bruise; an injury of soft tissues without breaking the overlying skin.
PREVIOUS AND NEXT TERMS--------------------------------------
Color opponency
When a cell is excited by one part of the visible spectrum and inhibited by another. First observed in ganglion cells in the retina.
Color opponent channel
Pathway that begins with the midget (parvo) ganglion cells in the retina and terminates within the parvocellular layer of the LGN. Conduction slower than that of Magnocellular Pathway.
Complex cells
Cells in the primary visual cortex (V1) that responding either to an edge, a bar or a slit stimulus of a particular orientation falling anywhere in its receptive field. The exact location of the stimulus within the receptive field is not as critical. Have receptive fields longer than those of simple cells. The cell behaves non-linearly, responding to a drifting cosine grating with a uniform increase in activity with no sinusiodal modulcation (i.e. insensitive to phase). For a historical perspective see Simple Cells.
Concentric field
A receptive field divided into an inner circular region and an outer ring-shaped region. Light falling in each of the two regions has opposite effects on the response of the cell.
Cone opsin
Light absorbing molecule in cone cells.
Contrast sensitivity function
Coplanar ratio hyphothesis
An hypothesis by Gilchrist in which the visual system does not use retinal contrasts to determine relative lightnesses but uses depth information to determine which regions are at the same depth (coplanar) and uses their contrasts to deteremine the lightness perceived. This hypothesis has come under recent attack.
Correspondence problem
In Stereopsis: the challenge of matching elements in one eye with elements in another eye. Also known as the Matching Problem. In Motion: the challenge of matching moving elements in one frame with elements in a succeeding frame (especially true of random dot cinematograms).
Corticaltectal pathway
Pathway from the cortex to the superior colliculi.
Cortical magnification factor
Defined as millimeters of cortex per degree of visual angle.
CPD
Cycles per degree of visual angle. The human limit is about 30cpd in the fovea for an individual with 20/20 vision.
RELATED TERMS--------------------------------------
Contrast
"Short for ""contrast media."" Contrast media are X-ray dyes used to provide contrast, for example, between blood vessels and other tissue."
Cell
Fundamental structural unit of all life. The cell consists primarily of an outer plasma membrane, which separates it from the environment; the genetic material (DNA), which encodes heritable information for the maintainance of life; and the cytoplasm, a heterogeneous assemblage of ions, molecules, and fluid.
Sensitivity
1. The reciprocal of the minimum stimulus strength required for the stimulus to be detected reliably (1/threshold) May be related to noise and other mechanisms. 2. Physiologically measured sensitivity averaged over many stimulus/response cycles. A measure of gain. Noise free.
SIMILAR TERMS--------------------------------------
Contac
Contac is a prescription or over-the-counter drug which is (or once was) approved in the United States and possibly in other countries. Active ingredient(s): chlorpheniramine maleate; phenylpropanolamine hydrochloride.
Contac 12 hour
Contac 12 hour is a prescription or over-the-counter drug which is (or once was) approved in the United States and possibly in other countries. Active ingredient(s): chlorpheniramine maleate; phenylpropanolamine hydrochloride.
Contact dermatitis
A rash or an inflammation of the skin caused by contact with various substances.
Contact dermatitis, allergic
Also called allergic contact eczema, this is a red, itchy, weepy reaction where the skin has come into contact with a substance that the immune system recognizes as foreign, such as poison ivy or certain preservatives in creams and lotions.
Contact eczema
A localized reaction that includes redness, itching, and burning where the skin has come into contact with an allergen (an allergy-causing substance) or with an irritant such as an acid, a cleaning agent or another chemical.
Contact eczema, allergic
Also called allergic contact dermatitis, this is a red, itchy, weepy reaction where the skin has come into contact with a substance that the immune system recognizes as foreign, such as poison ivy or certain preservatives in creams and lotions.
Contact healing
Another name for the alternative medicine practice of laying on of hands.
Contagious
Easily transmitted by direct or indirect contact.
Content validity
The extent to which a variable (for example, a rating scale) measures what it is supposed to measure (for example, self-care ability).
Contig
Contiguous sequence of DNA created by assembling overlapping sequenced fragments of a chromosome. A group of clones representing overlapping regions of the genome.
Contig map
A map depicting the relative order of a linked library of small overlapping clones representing a complete chromosome segment.
Contiguous gene syndrome
A disorder due to deletion of multiple gene loci that are adjacent to one another. Contiguous gene syndromes are characterized by multiple, apparently unrelated, clinical features caused by deletion of the multiple adjacent genes. Each of the individual genes within a contiguous region, when mutated, gives rise to a distinct feature.
Continence
The ability to hold in a bowel movement or urine.
Continent ileostomy
An operation to create a pouch from part of the small intestine. Stool that collects in the pouch is removed by inserting a small tube through an opening made in the abdomen.
Contingency reinforcement
In operant or instrumental conditioning, ensuring that desired behavior is followed by positive consequences and that undesired behavior is not rewarded.
Continuous passive motion machine
A machine used to help rehabilitate a limb (an arm or leg).
Contra Costa Regional Medical Center
The Contra Costa Regional Medical Center is a hospital in Contra Costa, California, United States.
Contraception
The intentional prevention of conception or impregnation. Also called birth control.
Contraceptive device, intrauterine (IUD)
A device inserted into the uterus (womb) to prevent conception (pregnancy). The IUD can be a coil, loop, triangle, or T in shape made of plastic or metal.
Contraceptive sponge, vaginal
A contraceptive device that is donut-shaped, made of plastic, contains a spermicide (nonoxynol-9) and is inserted into the vagina to cover the cervix. A loop is provided to ease removal.
Contraceptive, combined oral
"Commonly called ""the pill,"" combined oral contraceptives are the most commonly used form of reversible birth control in the United States. This form of birth control suppresses ovulation (the monthly release of an egg from the ovaries) by the combined actions of the hormones estrogen and progestin."
Contraceptive, diaphragm
A barrier method of contraception that is available by prescription only and must be sized by a health professional to achieve a proper fit.
Contraceptive, minipill
"A form of oral contraceptive taken daily, like combined oral contraceptives (the ""pill""), but containing only the hormone progestin and no estrogen. "
Contraceptive, pill
"Commonly called ""the pill,"" combined oral contraceptives are the most commonly used form of reversible birth control. This form of birth control suppresses ovulation (the monthly release of an egg from the ovaries) by the combined actions of the hormones estrogen and progestin."
Contract
A written, dated, and signed agreement between two or more involved parties that sets out any arrangements on delegation and distribution of tasks and obligations and, if appropriate, on financial matters. The protocol may serve as the basis of a contract.
Contraction
During labor, the strong, rhythmic tightening of the uterus. Pre-laborcontractions are usually irregular and don't increase in intensity orduration.
Contraction, uterine
"The tightening and shortening of the uterine muscles. During labor, contractions accomplish two things: (1) they cause the cervix to thin and dilate (open); and (2) they aid the baby to descend into the birth canal."
Contractions, Braxton Hicks
Irregular contractions of the womb (the uterus) occurring towards the middle of pregnancy in the first pregnancy and, earlier and more intensely, in subsequent pregnancies.
Contracture
Deformity caused by abnormal shortening of the muscles.
Contraindicate
To make a treatment or procedure inadvisable because of a particular condition or circumstance. For examples, certain medications are contraindicated during pregnancy because of the danger they pose to the fetus and the use of aspirin is clearly contraindicated in small children because of the danger of Reye syndrome.
Contraindication
A condition that makes a treatment not helpful or even harmful.
Contralateral
Affecting or pertaining to the opposite side.
Contrast
"Short for ""contrast media."" Contrast media are X-ray dyes used to provide contrast, for example, between blood vessels and other tissue."
Contrast media
"X-ray dye. Commonly spoken of as ""contrast."""
Contrast medium
A substance used in x-ray studies to aid in showing internal structures.
Contrast nephropathy
A form of acute renal failure that starts soon after administration of contrast media (dye) for X-rays. The disorder usually runs a benign course and only rarely requires recourse to dialysis.
Contrast sensitivity, visual
The ability to perceive differences between an object and its background.
Control (genetic)
The control of gene expression. Genetic control may be on the transcriptional or translational level. Transcriptional control works by controlling the number of RNA transcripts of a region of DNA, indirectly controlling protein synthesis. Translational control of protein synthesis works by regulating the step of translating RNA into protein.
Control (research)
In research, control subjects or control procedures permit comparison with experimental results.
Control group
The group of subjects in a controlled study that receives no treatment, a standard treatment, or a placebo instead of the therapy being investigated.
Controllable disease
disease or illness that can't be cured but can be managed with diet, exercise, or medications.
Controlled Disease
Taking care of oneself so that a disease has less of an effect on the body. People with diabetes can "control" the disease by staying on their diets, by exercising, by taking medicine if it is needed, and by monitoring their blood glucose. This care will help keep the glucose (sugar) level in the blood from becoming either too high or too low.
Controlled study
A study in which a test treatment is compared with a treatment that has known effects. The control group may receive no treatment, standard treatment, or placebo.
Contusion
A bruise; an injury of soft tissues without breaking the overlying skin.
PREVIOUS AND NEXT TERMS--------------------------------------
Color opponency
When a cell is excited by one part of the visible spectrum and inhibited by another. First observed in ganglion cells in the retina.
Color opponent channel
Pathway that begins with the midget (parvo) ganglion cells in the retina and terminates within the parvocellular layer of the LGN. Conduction slower than that of Magnocellular Pathway.
Complex cells
Cells in the primary visual cortex (V1) that responding either to an edge, a bar or a slit stimulus of a particular orientation falling anywhere in its receptive field. The exact location of the stimulus within the receptive field is not as critical. Have receptive fields longer than those of simple cells. The cell behaves non-linearly, responding to a drifting cosine grating with a uniform increase in activity with no sinusiodal modulcation (i.e. insensitive to phase). For a historical perspective see Simple Cells.
Concentric field
A receptive field divided into an inner circular region and an outer ring-shaped region. Light falling in each of the two regions has opposite effects on the response of the cell.
Cone opsin
Light absorbing molecule in cone cells.
Contrast sensitivity function
Coplanar ratio hyphothesis
An hypothesis by Gilchrist in which the visual system does not use retinal contrasts to determine relative lightnesses but uses depth information to determine which regions are at the same depth (coplanar) and uses their contrasts to deteremine the lightness perceived. This hypothesis has come under recent attack.
Correspondence problem
In Stereopsis: the challenge of matching elements in one eye with elements in another eye. Also known as the Matching Problem. In Motion: the challenge of matching moving elements in one frame with elements in a succeeding frame (especially true of random dot cinematograms).
Corticaltectal pathway
Pathway from the cortex to the superior colliculi.
Cortical magnification factor
Defined as millimeters of cortex per degree of visual angle.
CPD
Cycles per degree of visual angle. The human limit is about 30cpd in the fovea for an individual with 20/20 vision.
We thank you for using the Medical Glossary to search for Contrast sensitivity function. If you have a better definition for Contrast sensitivity function than the one presented here, please let us know by making use of the suggest a term option. This definition of Contrast sensitivity function may be disputed by other professionals. Our attempt is to provide easy definitions on Contrast sensitivity function and any other medical topic for the public at large.
This dictionary contains 19186 terms.
|
|