Sensation and Perception Flashcards
compare sensation to perception
looking out the window sensation is the wavelengths hitting the retina and perception is organizing the colors and shapes to recognize a tree
what are the 4 properties that sensory receptors communicate to the CNS
modality
location
intensity
duration
exteroceptors vs interoceptors
stimuli of outside world vs stimuli inside the body
olfactory and gustatory receptors are chemoreceptors , how do they differ
olfactory - respond to volatile chemicals in the air and are sensitive to many many different compounds
gustatory - respond to chemicals in food and only have a limited amount of tastes
mechanoreceptors are responsible for
touch
what are proprioceptors
give a sense of the relative position of the parts of our body in space
what is the difference between proximal and distal stimuli
proximal - what a sensory receptor detects , ie lightwaves hitting your eye
distal - the object that causes those signals , ie the bark and leave that absorb and emit certain wavelengths
what is the absolute threshold
what is crucial to remember about this
level of intensity a stimulus must have to be picked up by sensory neurons, usually about 50%
yes or no - if doesn’t reach threshold then nothing happened at all
can a stimulis be above the threshold of perception while still remain below the threshold of conscious perception
yes
what is the just noticeable difference
exactly what it sounds like
I can tell the difference between a 5 and 15 lb weight but not a 5 and 10lb
what is psychophysical discrimination testing
test whether subjects can tell the difference between two stimuli
ex. can you tell the difference between 5 and 10lb weight
what is webers law
any given sensory input the just noticeable difference will be a constant proportion of the original
I can tell the difference between 10 and 11 lb weight which is 10% so I can tell the difference between 100 and 110 lb weight
where does webers law break down
at the extremes
ex can’t tell the difference between a 10000 and 11000lb weight
what is signal detection theory
brain is filtering through input to identify signals that need responding to
use the bear analogy to represent all the terms in signal detection theory
bear is actually present and we perceive it as present and run - hit
bear is there and we don’t notice - miss
we think bear is there but it isn’t - false alarm
we dont think bear is there and its not - correct rejection
what is sensory adaptation
ability to get used to stimuli
ie don’t notice the shirt on your back
what are the two different types of receptors in regards to sensory adaptation
phasic - quick response to stimulus then stop ex.hair follicles
tonic - adapt slowly and continue to send action potentials as long as stimulus is present – think slowly sip gin and TONIC
difference between top down and bottom up processing
listening to a song
start off with perceiving the beat of the music and processing it to be a certain song - bottom up
then once you know the song your brain knows what should be coming next - top down
how can our sensory processing cause someone to not find an object thats right in front of you
top down - skim over it but you don’t expect it to be there
what are gestalt principles
how we perceive things as whole
best to just look at examples of these
principle of proximity
objects close together look like groups
principle of similarity
objects that are similar look like groups ex. if they’re all the same color
principle of good continuation
how can this be violated
if objects overlap we see them as lines or curves extending
by color that the principle of similarity would take over
principle of closure
we see complete shapes even when they aren’t
principle of symmetry
we see shapes that are symmetrical as a whole
what are cones for
color and fine detail
where are most of the cones found
fovea
what are rods for
visual input in low light
where are rods distributed
away from centre of retina so peripheral vision is good
what are rods made of
rhodopsin
what does the cornea do
protects the eye and focuses incoming light
what does the lens do
changes shapes to help the eye focus on objects at various distance
flat to see objects further away
round to help see nearer objects
describe the path through which light enters the eye
cornea anterior chamber lens posterior chamber retina
describe the cells involved in photo transduction
starts with the photoreceptors rods and cones in the retina
horizontal cells connect these to the bipolar cells which connect to ganglia cells via amacrine cells
how is the right visual field processed on the right and the left on the left side of the brain
travels through optic nerve then at the optic chiasm the nasal sides cross over
how does light information travel from the optic nerve to occipital lobe
after the optic chiasm the tract runs to the lateral geniculate nucleus in the thalamus which is resposible for sending signals to the superior colliculus
what are the two types of cells in the lateral geniculate nucleus
magnocellular - motion
parvocellular - picking up details
what is motion parallax and an example
objects closer to us move further across our visual field
this is why when your driving far away hills move slow but close by rush by very fast
what is parallel processing
integrating all input simultaneously
what is serial processing
sort incoming inout to find specific info
ex. looking for keys
describe the process of making sound
outer ear catches sound waves then the bones in the middle ear amplify the sound waves. endolymph bathed hair cells with stereo cilia detectors in the organ of corti turn the vibrations into an action potential that moves into the brain to the auditory cortex
what determines the frequency and amplitude of sounds
high frequency sound waves = high frequency vibrations
amplitude of waves = intensity
basic job of inner middle and outer ear
inner - converts mechanical signal to neural
middle - amplify sound wave
outer - gather sound wave
how are nerve cells in the organ of corti transferred to the brain
vestibulocochlear nerve to medial geniculate nucleaus in the thalamus to the auditory cortex in the temporal lobe
left vs right temporal lobe
left = speech right = music and background noise sounds
what is somatosensation
all sensation about and within the body
what is the 2 point threshold
min distance between 2 simultaneously stimulated points must be apart to be perceived as two points not just 1
what will have a lower 2 point threshold
fingers because there is more innervation
what is the gate theory of pain
body can turn pain signals on or off in the spinal cord
explains why a very painful stimulus can over ride a not so painful one
how is taste processed
taste centre of the thalamus then sent to the gustatory complex
how are smells processed
first in the olfactory bulb then passed along the olfactory tract to the limbic system (this is why smells can be associated with emotion!)
how can you determine the areas with lots of receptors
the homunculus guy who has big hands lips tongue and feet
