Biological Psychology
Visual field
area of the world that we can see at anytime
Fovea
each cone in the ____ has a direct line to the brain registering exact location of input
Receptive field
part of the visual field where any neuron responds
Di-chromats
people that see 2 colors
Mono-chromats
people that see black and white
Opponent process theory
proposed by Ewald Hering to explain negative color afterimage
Fovea
A tiny spot in the center of the retina that contains only cones; visual acuity is greatest at this spot, aka detailed vision
Which neurons are active
According to the law of specific nerve energies, the brain tells the difference between one sensory modality and another by:
relative activity of short, medium, and long wavelengths
According to the trichromatic theory of color vision, the most important factor in determining the color we see is the:
Fovea
Because blood vessels and ganglion cell axons are almost absent near the ____, it has nearly unimpeded vision.
Cones
Cones are utilized in color vision, daytime vision, and detail vision.
Retinex theory
Edward Land proposed the...
Law of Specific Nerve Energies
In modern terms, activity by a particular nerve always conveys the same kind of information to the brain is known as...
Law of Specific Nerve Energies
Johannes Muller wrote "whatever excites a particular nerve establishes a special kind of energy unique to that nerve" aka...
all-trans-retinol
Light energy converts 11-cis-retinal to...
Lens & Cornea
Light is focused as it enters through which structures
details of shape
Once within the cerebral cortex, the parvocellular pathway continues as a pathway sensitive to:
medial superior temporal cortex
One might find cells that respond best to the movement of an object relative to its background in the...
Lateral inhibition
Suppose someone has a genetic defect that prevents the formation of horizontal cells in the retina. Which visual phenomenon is most likely to be impaired
magnocellular neurons in the periphery
The ability to detect movement better than color in our peripheral vision is largely due to:
Facial recognition
The fusiform gyrus would be most excited in...
Visual receptors
The retina contains two types of specialized neurons, the rods and the cones and are considered...
Dorsal stream
The visual path in the parietal cortex is referred to as the:
Ventral stream
The visual paths in the temporal cortex collectively are referred to as the:
bar in a particular orientation
What is the shape of the receptive field to which a simple cell in the primary visual cortex responds
Complex
What type of cell responds to a pattern of light in a particular orientation anywhere within its large receptive field, regardless of the exact location of the stimulus
opponent-process theory
Which theory of color vision is best able to explain negative color afterimages
Inhibition
While light is striking a visual receptor, light begins also to strike the receptor next to it. What effect will this additional light have on the response of the first cell
opsins; photopigments
____ modify the ____ sensitivity to different wavelengths of light
Background
a certain wavelength of light can appear as several different colors depending on the...
Visual agnosia
a person is unable to recognize visual objects
Color constancy
ability to recognize colors despite changes in lighting
Blind spot phenomenon
ability to respond to visual info not seen
Retina stimulation
according to Purves "visual perception requires a reasoning process, not just...
Encoding
after sensory info reaches the nervous system, conversion of sensory information into a form that can be retained as a memory is called...
Shapes
are more easily identified with peripheral vision than foveal vision
Damage to Ventral Pathway
cannot fully describe what they see also impairs visual imagination & memory, see where but not what
Damage to Dorsal Pathway
cant reach out & grasp objects, can see what but dont remember how & where
Horizontal cell
combines all info & always send inhibitory not exititory nerve impulses
The brain
compares the color of 1 object with color of another subtracting a fixed amount of green from each
Retinex theory
concept that when info from various parts of the retina reaches the cortex, which compares each of the inputs to determine the color perception in each area
Primary visual cortex
damage to this area people report no conscious vision, visual imagery & no visual images in their dreams
Perception of the color green
decreased activity in the bi-polar cells will cause...
Perception
depends on frequency of firing, but its the frequency of 1 cell relative to the frequency of another cell
The nervous system
determines the color & brightness of lite by comparison the responses of different types of cones
Cortex
different parts of your ____ process, different aspects of vision can lose 1 while sparing others
Young-Helmholtz theory
emphasizes the idea that color vision depends on the relative responses of three kinds of cones?
Complex cells
found in both V1 & V2 don't respond to exact location of a stimulus but to a pattern of light in a particular orientation (i.e. vertical bar), responds equally throughout a large area
Photopigments
found in both cones & rods are chemical proteins that release energy when struck by light (transduction)
Parvocellular
ganglion cells transmit information about an object's color.
Why CVD people can't distinguish red from green
gene causing this deficiency on the X chromosome, 8% male & 1% female
Simple cells
has receptive field with fixed excitatory & inhibitory zones > light in excitatory zone = > cell response. > light in inhibitory zone = < cell response. Found in V1 only
Function of lateral inhibition
heighten contrasts e.g. when light falls on a surface bipolars inside the border are > excited while o/s are < excited
Approximately 6 million
how many cones are located in the retina
Approximately 120 million
how many rods are located in the retina
Perception
how we interpret sensation is also based on expectation is known as...
Daylight operation
increase cones to rods ratio equals...
Perception of the color red
increased activity in the bi-polar cells will cause...
Magnocellular neurons
larger cell bodies & receptive fields distributed evenly throughout retina
Magnocellular neurons
larger receptive fields, not color sensitive responds to moving stimuli, large patterns but not details. Included in the periphery explains why we see movement & not color (rods)
Rods
located at the outer edges of the retina are adapted for vision in dim light. Species that are active at night have few cones but many ____, giving them particularly good night vision.
Why CVD people can't distinguish red from green
long & medium wavelength cones have the same photo-pigment
Horizontal cells
make inhibitory contact onto bipolar cells, which in turn make synapses onto amacrine & ganglion cells
Retina rods & cones
make synapses with horizontal & bi polar cells
Red from green
most common form of CVD (color vision deficiency) people have trouble distinguishing..
Primary visual cortex
most visual info from the lateral geniculate goes to the...
Rod & cone distribution
reason why we have good color vision in the fovea but not the periphery
Visual receptors
receptors in the back of your eye that absorb light and transduce it into an electrochemical pattern in the brain
Lateral inhibition
reduction of activity in 1 neuron by activity in another
Amacrine cells
refine the input to ganglion cells, enabling them to respond specifically to shapes, movement, or other visual features
End stopped or hyper complex cells
resemble complex cells with the exception of strong inhibitory are at 1 end of its bar shaped receptive field to respond to bar shaped patterns of light.
Negative color afterimage
result of prolonged staring at a colored display then looking at a white surface to which 1 sees green where the display had been red, red were had been green & yellow where had been blue
Cones
retinal receptor cells that are concentrated near the center of the retina and that function in daylight or in well-lit conditions. They detect fine detail and give rise to color sensations
Temporal cortex
shape, movement & color brightness pathways all lead to the...
Human visual system
shortest visual wavelength 350nm-700nm violet to red
Parvocellular neurons
small cell bodies & receptive fields near fovea
Koniocellular neurons
small cell bodies occurring throughout the retina some are color sensitive & respond to varied but not yet fully described stimuli
Predatory birds
species has two foveas per eye, 1 pointing straight ahead and 1 Pointing to the side enabling perception of detail in the periphery
Optic nerve
starts with ganglion cells in the retina
Blind Spot
the ganglion cell axons from the optic nerve exits through the back of the eye, point of which leave a ___ _____ because there are no receptors
Optic nerve axons end at
the lateral geniculate, some @ hypothalamus, superior colliculus & elsewhere
Bipolar cells
the light sensitive cells in the retina
Lateral inhibition
the reduction of activity in one neuron by activity in neighboring neurons.
Ventral or Parvocellular pathway
the what pathway for object recognition & color (not motion)
Dorsal or Magnocellular pathway
the where or how pathway specialized for motion, location & brightness (not color)
Trichromatic
theory we perceive color through relative rates of response by 3 kinds of cones maximally sensitive to differing sets of wavelengths are sufficient to account for human color vision
Fovea
this receptor connects to a single bipolar connected to a single ganglion cell having an axon to the brain
Red, green, & blue (RGB)
three fovea cone colors
Transduction
transforming of stimulus energies, such as sights, sounds, and smells, into neural impulses our brain can interpret
Cant explain color constancy
trichromatic & opponent process theory...
Opponent process theory
we perceive color in terms of opposites; brain has a mechanism perceives color on a continuum from red-green, another from yellow-blue & another from white-black
Perpendicularly
we see only those rays that strike the retina...
Parvocellular neurons
well suited to detect visual details, respond to color being excited by small wavelengths & inhibited by others being close to the fovea (cones)
Long & medium wave length cones
what are more abundant than short (blue) cones, short are evenly distributed across the retina while the other 2 are spread haphazardly
Dorsal stream damage
what would cause an inability to reach out & grasp an object
White or gray
when all three cones are active we see the colors...
Transduction
when our eyes respond to light it is called
Occipital Cortex
where is the primary visual cortex (aka striate) located
CVD people
who are the only exception to the trichromatic theory
Complex cells
will respond to specific stimulus anywhere in their large receptive field
