sight Flashcards
structures in the eye
pupil –> forms an opening
iris –> controls color of eye and pupil size
muscles behind iris –> control lens
lens –> controls focus
cornea –> bends light to aid the lens in focusing
retina –> membrane in back of they eye
rods vs. cones
rods:
- operate at low levels of light
- night vision
- no color vision
- poor at fine detail
- located in the peripheral of the eye
cones:
- do poorly in low light
- love brightness
- see color
- see detail
- concentrated in the fovea
- located a little
proximity
tend to see stimulus elements that are near each other as part of the same group (groups)
similarity
elements that are similar tend to be grouped together (separating patterns)
closure
we tend to supply missing elements to close / complete a familiar figure (finishing the shape)
continuity
we tend to see elements in ways that produce continuous lines minimal change of direction (we see lines)
common movement / fate
when elements are moving in the same direction at the same rate, we tend to see them as part of a single object
good form or simplicity
the brain seeks the simplest explanation –> an object that is simmetrical may be seen as flat whereas when it isnt it may be seen as continuous lines
How do we see 3D
Different cues:
- binocular cues –> your eyes are in two different positions so you have two different images. your brain uses these cues to establish depth
- monocular cues
- motion parallax –> one of the most important features of depth perception. describes the rate of movement of objects in front of you to determine their distance.
- optic flow –> when you move you get this radial flow in the retina. based on the movement of objects around you, you get an idea of what direction youre headed in (like if youre in a train car looking out the window) **optic flow helps maintain balance
- Y shapes (three intersection points) imply corners
- L shapes (two intersection points) imply connections
- occlusion –> implies something in front
- we also pick up cues from shading and lighting
bottom up processing
we perceive local stimuli and bring them together to produce a whole
top down processes
making use of knowledge to help usperceive (recognizing patterns)
- uses the context effect –> which is using memory and the context of a situation to make a judgement
- ex. seeing a dalmation in a jumbled mess of dots
where is touch processed
parietal cortex
where is taste processed
insular cortex
where is sight processed
occipital lobe
where is smell processed
olfactory bulb (part of the prefrontal cortex)
where is sound processed
temporal lobe
first stop when processing a sensation
everything travels to the thalamus FIRST (except smell)
physical stimulus of audition
changes in air pressure over time
amplitude vs. frequency
amplitude –> loudness
frequency –> pitch (cycles per second)
- fewer cycles per second, lower pitch and vice versa
how does the auditory cortex map sounds
has a map correlating neurons to different frequencies
auditory localization
a combination of intensity and timing of sounds help us determine where theyre coming from
touch
senses pressure, temperature, and pain
- the receptor sends out an axon that goes to the brainstem, to the thalamus, then to the cortex
pain sensation
fast fiber –> mylenated, so information is sent right away (sharp, fast pain)
slow fiber –> nonmylenated, so information takes longer to be processed (duller, diffused pain)
open gate / closed gate
- a larger stimuli can block the firing of smaller nerve fiber firing (closing the gate)
- if you touch a burn it will block pain from being felt
smell
- molecules from the air enter the nasal passageway
- they are received by olfactory receptors in the olfactory epithelium
- information then travels to the olfactory bulb (for smell processing). this information is then relayed to different parts of the brain.
- via the olfactory nerve, the information goes to:
- the amygdala –> represents intensity (emotion/memory)
- prefrontal cortex –> represents pleasentness/unpleasentness
taste
- bumps in the tongue (papillae)
- taste receptors (taste buds) are located below in the walls
- attached to taste receptors is a nerve fiber that connects to spinal cord.
- information goes to thalamus and then frontal lobe
taste = …
taste + smell + appearance + mouth feeling
its multisensory –> thats why you cant taste when you cant smell
gestalt laws of perceptual organization
- proximity
- similarity
- closure
- continuity
- common fate / movement
dorsal
‘where’ pathway –> distance
ventral
‘what’ pathway
induced grating
gradient of colors and one same color across the center
brightness contrast
darker becomes lighter, lighter becomes darker
hermann grid
the grid with the dots
match bands
edge enhancement (the gradient)
Lateral inhibition simple explanation
Lateral inhibition is the phenomenon in which a neuron’s response to a stimulus is inhibited by the excitation of a neighboring neuron.
rate law
the principle that the strength of a stimulus is indicated by the rate of firing of the nerve impulses it elicits.
retina bipolar cells
transfer visual information from photoreceptors
retinal ganglian cells
collect information about the visual world from bipolar cells and propagate visual stimuli to the brain
horizontal cells
integrate and regulate the input from multiple photoreceptor cells
amacrine cells
receive synaptic input from bipolar cells and other amacrines, and in turn provide input to amacrine and ganglion cells
doctrine of specific nerve energies
the concept that the quality of a sensory experience is determined by the type of sensory receptor and its nerve channels
transduction
action or process of converting something and especially energy or a message into another form
patient DF
has a form of agnosia. has trouble visually locating and identifying objects
prosopagnosia
a neurological disorder characterized by the inability to recognize faces
visual agnosia
an impairment in recognizing visually presented objects, despite otherwise normal visual field
balints syndrome
difficulty perceiving multiple objects simultaneously
effects of medication
block nerve transmission to pain centers in the central nervous system by binding to and inhibiting the function of an ion channel
Psychophysics
branch of psychology that deals with physical stimuli and mental phenomena
Perceived size =
(retinal image size) x (perceived distance)
cochlear implant
stimulates the auditory nerve
vestibular sense
receptors in the semicircular canals in inner ear contain liquid. it stimulates hair which generates impulses. this tells the orientation of the head.
kinesthesis
information about the muscles and joints
