Chapter 6 Flashcards
Sensation
The process in which specialized cells of the nervous system detect environmental stimuli and transducer their energy into receptor potentials
Perception
The conscious experience and interpretation of information from the senses
Hue
One of the perceptual dimensions of color; the dominant wavelength
Brightness
One of the perceptual dimensions of color; intensity
Saturation
One of the perceptual dimensions of color; purity
Sensory receptor
A specialized neuron that detects a particular category of physical events
Sensory transduction
The process by which sensory stimuli are transducer into slow graded receptor potentials
Receptor potential
A slow graded electrical potential produced by a receptor cell in response to physical stimulus
Retina
The neural tissue and photoreceptive cells located on the inner surface of the posterior portion of the eye
Accommodation
Changes in the thickness of the lens of the eye accomplished by ciliary muscles that focus images of near or distant objects in the retina
Rod
One of the receptor cells of the retina; sensitive to light of low intensity
Coke
One of the receptor cells of the retina; maximally sensitive to one of three different wavelengths of light and hence encodes color vision
Photoreceptors
One of the receptor cells of the retina; transducer photic energy into electrical potentials
Fovea
The region of the retina that mediates the most acute vision of birds and higher mammals. Color sensitive cones constitute the only type of photo receptor found in the fovea
Optic disk
The location of the exit point from the retina of the fibers of the ganglion cells that form the optic nerve; responsible
For blind spot
Bipolar cell
A bipolar neuron located in the middle layer of the retina, converting information from the photoreceptors to the ganglion cells
Ganglion cell
A neuron located in the retina that receives visual information from the bipolar cells; it axons gives rise to the optic nerve
Horizontal cell
A neuron in the retina that interconnects adjacent photoreceptors and the outer processes of the bipolar cells
Amacrine cell
A neuron in the retina that interconnects adjacent ganglion cells and the inner processes of the bipolar cells
Photopigment
A protein dye bonded to retinal, a substance derived from vitamin A; responsible for transduction of visual information
Lamella
A layer of membrane containing photopigments; found in rods and cones of the retina
Olson
A class of protein that together with retinal constitutes the photopigments
Retinal
A chemical synthesized from vitamin A; joins with an opsin to form photopigment
Rhodopsin
A particular opsin found in rods
Receptive field
That portion of the visual field in which the presentation of visual stimuli will produce and alteration in the firing rate of a particular neuron
Vergence movement
The cooperative movement of the eyes which ensures that the image of an object falls on identical portions of both retinas
Saccadic movement
The rapid jerky movement of the eyes used in scanning a visual scene
Pursuit movement
The movement that the eyes make to maintain and image of a moving object on the fovea
Optic nerve
Bundles of axons from retinal ganglion cells exit the eye and convert information to the lateral geniculate nucleus
Dorsal lateral geniculate nucleus
A group of cell bodies within the lateral geniculate body of the thalamus; received input from the retina and projects to the primary visual cortex
Optic chiasm
A cross shaped connection between the optic nerves located below the base of the brain just anterior to the pituitary gland
Visual pathway
The pathway of visual processing from the retina to the lateral geniculate nucleus to striate and extrastriate virtual regions
Striate cortex
Primary visual cortex
Extrastriate cortex
A region of visual association cortex; receives fibers from the striate cortex and form the superior follicular and projects to the inferior temporal cortex
Magnocellular layer
One of the inner two layers of neurons in the dorsal lateral geniculate nucleus; transmits information necessary for the perception of form, movement, depth, and small differences
Parvocellular layer
One of the four outer layers of neurons in the dorsal lateral geniculate nucleus; transmits information necessary for perception of color and fine details to the primary visual cortex
Koniocellular sublayers
One of the sublayers of neurons in the dorasal lateral geniculate nucleus found ventral to each of the magnocellular and parvocellular layers; transmits information from short wavelength cones to the primary visual cortex
Dorsal stream
A system of interconnected regions of visual cortex involved in the perception of spatial location beginning with the striate cortex and ending with the posterior parietal cortex
Ventral stream
A system of interconnecting regions of visual cortex involved in the perfectionist of form beginning with the striate cortex and ending with the inferior temporal cortex
Protanopia
An inherited form of defective color vision in which red and green hues are confused; red cones are filled with green cone opsin
Deuteranopia
An inherited form of defective color vision in which red and green hues are confused; green cones are filled with red cone opsin
Tritanopia
An inherited form of defective color vision in which hues with short wavelengths are confused; blue cones are either lacking or faulty
Negative afterimage
The imagine seen after a portion of the retina is exposed to an intense visual stimulus; consists of colors complementary to those of the physical stimulus
Complementary colors
Colors that make white or gray when mixed together
Cerebral achromatopsia
Inability to discriminate among different hues; caused by damage to the visual association cortex
Visual agnosia
Deficits in visual perception in the absence of blindness; caused by brain damage
Lateral occipital complex
A region of the extrastriate cortex, involved in perception of objects other than people’s bodies and faces
Prosopagnosia
Failure to recognize particular people by the sight of their faces
Fusiform face area
A region of the visual association cortex located in the inferior temporal lobe; involved in perception of faces and other simplex objects that require expertise to recognize
Retinal disparity
The fact that points on objects located at different distances from the observer will fall on slightly different locations on the two retinas; provides the basis for stereopsis
Posterior parietal cortex
The highest level of the dorsal stream of the visual association cortex; involved in perception of movement and spacial location
Optic flow
The complex motion of points in the visual field caused by relative movement between the observer and environment; provides information about the relative distance of objects from the observer and of the relative direction of movement
Akinetopsia
Inability to perceive movement cause by damage to area V5 of the visual association cortex
