Sensation & Perception Exam #1
Suppose that you stand 20 feet from the Snellen chart. If you can read the letters that a person with normal sight can read at 20 feet, then you have ______ vision. If you have poor acuity, however, you would have to stand closer to read the letters. If you need to stand 20 feet from the chart to read the letters clearly that a normal person could see at 40 feet, then you would have _________ vision.
20/20; 20/40
About ____% of light making it to the cornea is reflected away or absorbed before getting to the retina.
50%
The fovea has a visual angle of _________ degrees. Furthermore, the rod-free part at the center of the fovea, which also has the greatest concentration of cones, has a visual angle of ________ degrees.
5; 2
_______ is a syndrome that is a form of anosognosia that results in damage to visual processing and the part of the brain that knows its blind. Patient's deny that they are blind despite objective evidence of visual loss. This is a rare extension of ______ blindness.
Anton's syndrome; cortical
The view of perception in which the world is exactly as it appears, resulting in illusions, is called __________.
Naive Realism
Ganglion cells are not sensitive to ______ amount of brightness but are instead sensitive to _____ differences between center & surround.
absolute; relative
The proportion/percentage of light reflected by a surface is the ________. It remains ______ despite changes in the amount of light falling on an object
albedo; constant
The ______ are arranged across multiple bipolar cells in a specific order. They apparently have no axons but have over 20 varieties. They may serve to switch inputs to _______ cells from rods and cones and back again as needed. They respond to _______ objects.
amacrine cells; ganglion; moving
The height of a light wave is called ___________. This is related to ______________.
amplitude; brightness
Color
an illusion; the means by which our brain tells us that the wavelengths of light entering our eyes are different; different rates of vibration determine our perception of color and our ability to see color is really just our ability to see waves
A part of the vascular tunic layer that contains the iris, pupil, and lens is called the _____________.
anterior chamber
__________ is the clear fluid that is created in the vascular tunic--the lens particularly--and flows through the pupil and into the anterior chamber; too much of this can cause a build up of pressure leading to ________.
aqueous humor; glaucoma
A visual disorder in which the cornea is not perfectly round but is uneven in shape is called a(n) ________. It produces _______ of images as the eye is focused for some parts of the cornea but out of focus for others.
astigmatism; warping;
Activation from rods and cones results in signals sent to _______ cells. The possible function of these cells is to pass on increases/decreases in lightness.
bipolar cells
________ provides moisture, cleanses the eye's surface, and its frequency is related to environment, socialization, and emotion.
blinking
Locations where neural events from the eye are processed and interpreted are called ____________.
brain regions
How bright a color is perceived to be, dependent on the context, is called __________. This is related to _________.
brightness; amplitude
A discoloration of the lens, "fixed" by removing the lens (can no longer focus or accommodate at all) is called a _____________.
cataract
Retinal ganglion cells with the smallest receptive field are found in the ___________
center of the retina
The ________ is a part of the vascular tunic where pigment resides; pigment absorbs light, reducing light scatter
choroid
Cells in the primary visual cortex that respond most vigorously to moving stimuli are _______. Their preferred stimuli are not as clearly related to the _________, but rather stimuli that are of specific ________.
complex cells; receptive fields; orientation
A type of receptive field in which some cells (______) respond only to movement in a specific direction is called _______.
complex; direction selectivity
The photopigment in __________ involves lights of 440 nm, 530 nm, and 560 nm (violet, green, yellow) that produces the best response. ________, _________, and ________ are the photopigments in this photoreceptor.
cones; S-cones (blue cones); M-cones (green cones); L-cones (red cones)
______ (of photoreceptors) refers to the number of photoreceptors that synapse onto each ganglion cell. For the _____, a great deal of ______ occurs. For the ______, much less ________ occurs. When photoreceptors share ganglion cells, it provides greater ________.
convergence; rods; convergence; cones; convergence; sensitivity
WWI individuals who had injuries in the primary visual cortex and showed blindness without eye damage is an example of _________.
cortical blindness
An overrepresentation of information from the fovea with respect to the cortex is called __________. A far greater proportion of cortical tissue is located in the ______ portion of the retinal field (the ______). ___% of all cortical cells are devoted to the central _____ degrees of the visual field.
cortical magnification; central; fovea; portion of the retinal field (fovea); 80%; 10
An increase in sensitivity that occurs as the eyes remain in the dark is called ________. This takes about 30 minutes as opposed to ________, which takes only 1 minute, and is a decline in sensitivity that occurs as the eyes remain in the light. Our _____ adapt rapidly but are insensitive. Our _____ adapt slowly but are more sensitive.
dark adaptation; light adaptation; cones; rods
When an action potential changes from its negative state to a positive state, _______ takes place
depolarization
There are three types (varieties) of receptive fields: _______, ______, and ________.
direction selectivity;orientation selectivity; size selectivity
_______ light must be made to converge on the retina
divergent
______________ is the different ranges of light waves depending on the source and produced by electrically charged particles.
electromagnetic radiation
An eye that naturally focuses light exactly on the retina, with good convergence, is __________.
emmetropic
The ________ is the structure that captures light & converts it to a neural event.
eye
Senses, such as seeing and hearing, that do NOT require close proximity to a stimulus to detect/perceive it are called _____________. These senses have a ______ reaction time.
far (distance) senses; slow
The outermost protective "skin" of the eye, which is relatively tough, not very elastic, and contains the cornea (which has no blood vessels), is called the ____________.
fibrous tunic (sclera)
From outer to inner, ___________, ___________, __________ make up the 3 layers of the eye.
fibrous tunic (sclera); vascular tunic; retina
The portion of the retina with the most acute vision/resolution (clarity), that is 0.3 mm in diameter, is called the ___________.
fovea
The only cells that communicate with the brain, and that receive input from 100 receptor cells, collectively known as a receptive field, are called ________. Its axons form the _______, and some rods/cones overlap and _____ some of these cells. These cells run from the _______ of the retina toward the brain.
ganglion cells; optic nerve; share; bipolar cells
_________ occurs when a buildup of pressure within the eye occurs, eventually damaging nerve cells in the optic disc.
glaucoma
Cortical cells seem to respond best to ______(sudden changes) in light intensity (borders, edges, etc.) and are not too responsive to levels of (or overall changes in) _______. Therefore, most, if not all cortical activity occurs only at the _____ of objects.
gradients; illumination; edges
Light waves that have _________ amplitude are typically perceived as brighter, while light waves that have _________ amplitude are typically perceived as dim.
greater; smaller
The _______ make contact with receptor cells and receptor cells make contact with them. Their basic job is to inhibit the receptor cells' firing, effectively turning off the weakly activated cells and strengthening active cells. This results in a clearer overall ________.
horizontal cells; visual angle
_______ is the psychological experience/perception of a color; the psychological experience of the physical property of ___________.
hue; wavelength
______ or _______ refers to people who are farsighted and cannot see nearby objects. There is too little optical power in which the eye is "too _______" (light converges ______ reaching the retina).
hypermetropic; hyperopia; short; after
When an action potential changes from its negative state to a more negative state, _______ takes place.
hyperpolarization
The ring of pigmented muscles that contract to adjust/alter the pupil size is the ___________.
iris
The perceived "unevenness" of brightness near the borders of Mach Bands occurs because of _________.
lateral inhibition
Inhibition of neural activity for points near the part of the retina that is stimulated by light is called _________. Cells try to suppress the ______ of neighboring cells (" sideways suppression"). The more intense a cell ______, the more intensely it will try to _______ its neighbors. This enhances ______ but has the side effect of producing illusions such as ________.
lateral inhibition; firing; fires; suppress; edges; mach bands
The __________ is surrounded by the ciliary muscle, determines focus, accommodates to change shape (thick= near objects; thin = far objects), and as it gets older, it can no longer accommodate leading to presbyopia.
lens
The portion of the electromagnetic radiation spectrum made up of waves that range from about 400 to about 700 nm is called __________.
light
A phenomenon in which bright and dark regions are perceived within a single stripe, although there is no corresponding variation in the physical distribution of light, is called _________.
mach bands
______ conditions exist when the light is sufficiently bright that cones are still functional, but sufficiently dim that rods can also function. In other words, ______ uses both rods and cones.
mesopic; mesopic vision
A person who requires only one color to match his or her perception of all other colors is a _________. This person would be ________, as he/she would have only _____ in his/her retina. Every ____ would look identical to this person.
monochromat; colorblind; rods; hue
_____ is useful for insulating axons and speeding neural transmission. However, there are no _______ axons until the ______ cells exit the eye, because they would take up too much space in the _______.
myelin; myelinated; ganglion; optic disc
_____ or ____ refers to people who are nearsighted and cannot see faraway objects. There is too much optical power in which the eye is "too _______" (light converges ______ reaching the retina).
myopic; myopia; long; before
The means by which wavelength is measured is by a ___________________ (one-billionth of a meter).
nanometer
Senses, such as taste, touch, and smell, that DO require close proximity to a stimulus in order to detect/perceive it are called _________. These senses have a _______ reaction time.
near senses; fast/immediate
In an ____-center, ____-surround situation, a ganglion cell is maximally excited when there is darkness in the center and lightness surrounding. This is possibly our initial system in detecting ________ of light.
off; on; decrements
In an _____-center, ____-surround situation, a ganglion cell is maximally excited when there is lightness in the center and darkness surrounding. This is possibly our initial system in detecting _______ of light.
on; off; increments
The area in which the two optic nerves come together and cross over/converge is the _______. In humans, _____ of the fibers from each eye project into the same (_______) hemisphere while the other ______ go to the opposite (_______) hemisphere. This cross-over occurs because images are _______ on our retinas.
optic chiasm; 50%; ipsilateral; 50%; contralateral; inverted
The blind spot where nerve fibers exit the eye to portions of the brain is called the ____________.
optic disc
Axons from the retinal ganglion cells exit the eye and form the ________.
optic nerve
The bundle of nerve fibers in the visual system that runs between the optic chiasm and the superior colliculus or the lateral geniculate nucleus are the ________. Each one contains ____ from both eyes. This is what the ______ turns into after going through the optic chiasm.
optic tracts; fibers; optic nerve
Components that help protect the eye include:
orbit, orbital fat, eyelids, & blinking
A type of receptive field in which some cells respond so finely that a mere 15 degree change in optimum angle will abolish a cell's response to it (ex. a clock's hand moving from 12:00 to 12:03) is called _________. This is demonstrated by the ______ effect. Superiority in visibility of horizontal/vertical edges is relative to edges not of _______ orientations. _____ degree angles = WORST visual acuity (i.e., we are good at straightening rectangular frames but not good when frames deviate from NS/EW).
orientation selectivity; oblique; NS/EW; 45;
The label/interpretation you place on a sensation is called ___________.
perception
Receptive fields are larger in the ________.
periphery
______ involves seeing in bright light. Only _____ (color, resolution, and acuity) are used.
photopic vision; cones
___________ consist of 2 light-sensitive molecules: the protein opsin and the vitamin A derivative retinal. ALL _________ is the same but _______ varies which is what gives us different sensitivities to light frequencies. These light-sensitive molecules determine spectral frequencies we see.
photopigments; retinal; opsin
Rods & cones are _____________. Rods detect _________ and ________ while cones detect _______ and _______.
photoreceptors; brightness; sensitivity; color; clarity
The biggest portion of the eye, filled w/ an egg-white like substance called vitreous humor (which is not continuously replaced) is called the ______________.
posterior chamber
A type of farsightedness that occurs with aging and that is caused by elasticity of the lens is called _______. The lens ______, decreasing its ability to focus (_________).
presbyopia; hardens; accommodate
The area of the brain, also known as Area 17, VI, or striate cortex, is called the ________. Animals will behave as though _______ when this region is removed or destroyed.
primary visual cortex; blind
The relative _______ of fibers from each eye depends on the location of the eyes in the heads of different species. Humans have a _______ cross-over, while rabbits, for example, have a cross-over of ______. Eyes with visual scenes that do not overlap project ____% to the opposite hemisphere.
proportion; 50/50; 0; 100%
People with the disorder ___________ are incapable of organizing facial features to recognize a face.
prosopagnosia
An opening in the iris, whose size determines the amount of light entering the eye & is influenced by the ANS is called the ___________.
pupil
The number of wavelengths of a stimulus and the extent that the light is composed of a single wavelength versus a mixture of wavelengths is called ____________. This is the physical property of the perception of _________.
purity; saturation
For a given cell, the patch of the retina that alter's a cell's response when stimulated by light is a _________. There are two types: _________ and __________. The ______ are antagonistic.
receptive field; on-center, off-surround; off-center, on-surround; surrounds
The five major classes of retinal cells are ____, _____, ____, ____, and _____.
receptor cells, horizontal cells, bipolar cells, amacrine cells, and ganglion cells
Rods and cones are the ______ cells for light. Rods produce _____ and ____ light while cones produce _____ and ____ light. We have ____ rods and ______ cones.
receptor; brightness; dim; color; bright; 100 million; 5 million
_______, or clarity, requires small receptive fields. Few receptors feed into a ganglion cell. This demonstrates how there are primarily ______ in the fovea, which involves the _______ acuity.
resolution; cones; highest
The _________ is the innermost layer of the eye; light detecting layer that develops out of the same tissue as the brain & is therefore a direct extension of the CNS; includes the fovea, optic disc, photoreceptors, and photopigments
retina
The photopigments in ____________ involve light of 500 nm (bluish-green) that produces the best response. ________ is the photopigment in this photoreceptor.
rods; rhodopsin
The degree of richness perceived in a color, or how "good" a color is, is called _________. This is the perception of the physical property of __________.
saturation; purity
A blind area caused by damage to the visual cortex, is called a(n) _______. The _______ of the retinal image is maintained.
scotoma; topography
_____ involves seeing in dim light. Only _____ (brightness/sensitivity to light) are used.
scotopic; rods
The initial detection of energy from the physical world BEFORE you know what it is is called __________.
sensation
The ability to detect a change in the stimulus (e.g., light, temperature, etc.) is called _______. Greater amounts comes from ________, which is to say, from larger receptive fields.
sensitivity; spatial summation
Cells in the primary visual cortex that respond most vigorously to lines are ________. There is a simple _____ between their receptive field layouts and their preferred stimulus.
simple cells; relation
A type of receptive field in which some cells respond to objects of a specific size, reflecting the variation in field size as is the case in the retina, is called ________. In the visual cortical area, both ____ & ______ tend to be tied together (ex. thick vs. think bar/edge at a specific angle).
size selectivity; size; orientation
Adding together/increasing the number of receptors that contribute to a retinal ganglion cell is known as _______________.
spatial summation
The view of perception in which our senses are limited in gathering real info about the world but they also enhance what is available is called _____________.
standard view
The intensity of light barely detected is the ________.
threshold
The process of converting light energy into neural energy is called ___________.
transduction
The middle layer of the eye that contains a network of blood vessels that nourish the eye, reduces light scatter & helps absorb light, hugs the outer wall except near front of the eye, produces aqueous humor, is divided into two compartments (anterior and posterior chambers), and includes the iris, pupil, lens, and vitreous humor is called the __________________.
vascular tunic
_________ is the ability to see fine details in a scene.
visual acuity
_____________ means the size of the angle formed by extending two lines from your eye to the outside of a target.
visual angle
People with _______ have basic visual abilities but cannot recognize objects.
visual object agnosia
An egg-white like substance found in the posterior chamber is called ____________. "Floaters" can be found here.
vitreous humor
The stimulus for color and the distance light travels in one cycle is called __________. This is the physical property of the psychological experience of ________.
wavelength; hue