Biopsych Chapter 6

Front 1

sensory receptor

Back 1

a specialized neuron that detects a particular category of physical events

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sensory transduction

Back 2

the process by whcih sensory stimulie are transcued into slow, graded receptor potentials

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receptor potential

Back 3

a slow, graded electrical potential produced by a receptor cell in response to a phyisical stimulus

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hue

Back 4

one of the perceptual dimensions of color; the dominant wavelength

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brightness

Back 5

one of the perceptual dimensions of color; intensity

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saturation

Back 6

one of the perceptual dimensions of color; purtiy

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saccadic movement

Back 7

the rapid, jerky movement of the eyes used in scanning a visual scene

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pursuit movement

Back 8

the movement that the eyes make to maintain an image of a moving object on the fovea

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accommodation

Back 9

changes in the thickness of the lens of the eye; accoomplished by the ciliary muscles, that focus images of near or distant objects on the retina

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retina

Back 10

the neural tissue and photoreceptive cells located on the inner surface of the posterior portion of the eye

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rod

Back 11

one of the receptor cells of the retina; sensitive to light of low intensity

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cone

Back 12

one of the receptor cells of the retina; a maximally sensitvive to one of three different wavelengths of light and hence encodes color vision

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photoreceptor

Back 13

one of the receptor cells of the retina, transduces photic energy into electrical potentials

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fovea

Back 14

the region of the retina that mediates the most acute vision of birds and higher mammals. Color-sensitive cones constitute the only type of photorecptor found in this area

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optic disk

Back 15

The location of the exit point form the etina of the fibers of the ganglion cells that form the optic nerve; responsible for the blind spot

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bipolar cell

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a bipolar neuron located in the middle layer of the retina, conveying information from the photoreceptors to the ganglion cells

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ganglion cell

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a neuron located in the retina that receives visual infromation from bipolar cells; its axons give rise to the optic nerve

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horizontal cell

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a neuron in the retina that interconnects adjacent photoreceptors and the outer processes of the biopolar cells

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amacrine cell

Back 19

a neuron in the retina that interconnects adjacent ganglion cells and the inner processes of the bipolar cells

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lamella

Back 20

a layer of membrane containing photopigments; found in the rods and cones of the retina

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photopigment

Back 21

a protein dye bonded to retinal, a substance derived from vitamin A; responsible for transduction of visual information

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opsin

Back 22

a class of protein that, together with retinal, constitutes the photopigments

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retinal

Back 23

a chemical synthesized from vitamin A; joins with an opsin to form a photopigment

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rhodospin

Back 24

a particular opsin found in rods

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dorsal lateral geniculate nucleus (LGN)

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a group of cell bodies withing the lateral geniculate body of the thalamus; receives inputs from the retina and projects to the primary visual cortex

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magnocellular layer

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one of the inner two layers of neurons in the LGN; transmits information necessary for the perception of from, movement, depth, and small differences in brightness to the primary visual cortex

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parvocellular layer

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one of the four outer layers of neurons in the LGN; transmits the information necessary for perception of color and fine details to the primary visual cortex

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koniocellular sublayer

Back 28

one of the sublayers of neurons in the LGN found ventral to each of the magnocellular and parvocelluar layers; transmits information from short-wavelength(blue) cones to the primary visual cortex

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calcarine fissure

Back 29

a horizontal fissure on the inner surfaces of the posterior cerebral cortex; the location of the primary visual cortex

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striate cortex

Back 30

the primary visual cortex

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optic chiasm

Back 31

a cross-shaped connection between the optic nerves, located below the base of the brain, just anterior to the pituitary gland

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receptive field

Back 32

the portion of the visual field in which the presentation of visual stimuli will produce an alteration in the firing rate of a particular neuron

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protanopia

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an inherited form of defective color vision in which red and green hues are confused, red cones are filled with green cone opsin

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deuteranopia

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an inherited from of defective color vision in which red and green hues are confused; green cones are filled with red opsin

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tritanopia

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an inherited form of defective color vision in which hues with short wavelengths are confused, blue cones are lacking or faulty

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simple cell

Back 36

an orientation-senstive neuron in the striate cortex whose receptive field is organized in an opponent fashion

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complex cell

Back 37

a neuron in the visual cortex that responds to the presence of a line segment with a praticular orientation locaded within its receptive field, especially when the line moves perpendicularly to its orientation

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hypercomplex cell

Back 38

a neuron in the visual cortex that responds to the presence of a line segment with a particular orientation that ends at a particular point within the cell's receptive field

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sine-wave grating

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a series of straight parallel bands varying continuously in brightness according to a sine-wave functin, along a line perpendicualr to their lengths

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spaital frequency

Back 40

the relative width of the bands in a sine-wave grating, measured in cycles per degree of visual angle

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retinal dispartiy

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the fact that points on objects located at different distances form the observer will fall on slightly different locations on the two retinas; porvides the basis for stereopsis

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cytochrome oxidase (CO) blob

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the central region of a module of the primary visual cortex, revealed by a stain for cytochrome oxidase; contains wavelenght-sensitive neurons; part of the parvocellular system

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extrastiate cortex

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a region of the visual association cortex; receives fibers from the striate cortex and from the superior colliculi and projeccts to the inferior temporal cortex

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dorsal stream

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a system of inter-connected regions of visual cortex involved in the perception of spatial location, beginning with the striate cortex and ending with the posterior parietal cortex

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ventral stream

Back 45

a system of interconnected regions of visual cortex involved in the pereception of form, beginning with the striate cortex and ending with the inferior temporal cortex

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color constancy

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the relatively constant appearence of colors of objects viewed under varying lighting conditions

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cerebral achromatopsia

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inability to discriminate among different hues; caused by damage to area V8 of the visual association cortex

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visual agnosia

Back 48

deficits in visual form pereception in the absence of blindness, cause by brain damage

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lateral occipital complex (LOC)

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a region of the extrastriate cortex, involved in perception of objects other than people's bodies and faces

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prosopagnosia

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failure to recognize particula people by the sight of their faces

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fusiform face area (FFA)

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a region of the visual association cortex located in the inferior temporal; involved in pereception of faces

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extrastriate body area (EBA)

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a region of the visual association cortex located in the lateral occipitotemporal cortex; involved in perception of the human body and body parts other than faces

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parahippocampal place area (PPA)

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a region of the medial temporal cortex; involved in perception of particular places (scenes)

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optic flow

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the complex motion of points in the visual field cuased by relative movement between the observer and environment; provides information aboutt he relative distance of objects from the observer and the relative direction of movement

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akinestopsia

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inablilty to perecive movement, cuased by damage to area V5, also called MST, of the visual association cortex

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intraparietal sulcus (IPS)

Back 56

the end of the dorsal stream of the visual assiciation cortex, involved in perectption of location, visual attention, and control of eye and hand movements