SENSORY PERCEPTION Flashcards
what do visual cues allow us to do as humans?
perceptually organize by taking into account DEPTH, FORM, MOTION & CONSTANCY
what do two eyes allow humans to do?
receive visual cues from their environment by binocular cues
receiving visual cues from the environment by binocular cues gives human a sense of
depth
human eyes being ~2.5 inches apart allowing humans to get slightly different views of objects of the world around gives
retinal disparity
convergence gives human an idea of depth based on what?
convergence gives humans an idea of depth based on how much their eyeballs turn
describe the muscles of the eyes when things are far away or closer
when things are far away, muscle relaxed. when things are closer, muscles contract
what do we call the cues humans receive in which they do not need two eyes for?
monocular cues
monocular cues give humans a sense of
form
differentiate what sense binocular and monocular cues provide
binocular - depth
monocular - form, motion, constancy
describe relative size in terms of the sense of form
can be inferred with one eye. The closer an object isdescr, the bigger it looks
describe interposition/overlap
the perception that one object is in front of another and that the one in front is closer
describe relative height
things higher are perceived to be farther away than things lower
describe the concept of shading and contour
using light and shadows to perceive form. depth(contour), crater(mountain)
what is motion parallax?
things farther away move slower, things closer move faster
what is the monocular cue of constancy?
our perception of an object does not change even if the image cast on the retina is different.
what are the 3 different types of constancy?
size, shape and color
size constancy
object that appears larger because it is closer, we still think it’s the same size
shape constancy
a changing shape still maintains the same shape perception
color constancy
despite changes in lighting which change the image color falling on our retina, we understand that the object is the same color
what does the principle of sensory adaptation explain>
our senses are adaptable and they can change their sensitivity to stimuli
does the inner ear muscle contract or relax in response to high noise?
contracts to dampen vibration in inner ear and protect eardrums
with the sense of touch, how are temperature receptors affected over time?
they’re desensitized over time
with the sense of smell, how are receptors to molecule sensory information affected over time?
they’re desensitized over time
what is proprioception?
sense of position of the body in space, sense of balance/where you are in space.
differentiate down and up regulation in terms of sense of sight
in down regulation(light adaptation), pupils constrict in response to light desensitizing rods and cones. In up regulation(dark adaptation), pupils dilate as rods and cones start synthesizing light sensitive molecules.
what is Weber’s law?
JND(^I) / I (initial intensity) = k(constant)
the threshold at which you are able to notice a change in any sensation is called
Just Noticeable Difference (JND)
what does the weber’s law predict?
linear relationship between incremental threshold and background intensity
how do you measure the JND (difference threshold)
I x k
what is absolute threshold of sensation?
it is the minimum intensity of stimulus needed to detect a particular stimulus 50% of the time
what factors affect the absolute threshold?
various physiological states like expectations, experience, motivation, alertness.
the stimuli below the absolute threshold of sensation is known as
subliminal stimuli
what are the types of somatosensation?
temperature-thermoception
pressure-mechanoception
position-proprioception
pain-nociception
describe somatosensation intensity
how quickly neurons fire for us to notice. Slow-firing: low intensity, fast-firing: high intensity
what are the 3 ways neurons encode for timing?
fast-adapting, slow-adapting and non-adapting
describe non-adapting neuron encoding
neuron fires at a constant rate
describe slow-adapting neuron encoding
neurons fire at the beginning of stimulus then calm down after a while
describe fast-adapting neuron encoding
neurons fire as soon as stimulus starts then stops firing, and starts again when stimulus stops
location-specific stimuli by nerves are sent to the brain and rely on
dermatomes
the vestibular system relates to
balance and spatial orientation coming from both inner ear and limbs
what part of the inner ear supports the vestibular system?
the semicircular canals; posterior, lateral and anterior
what is the semicircular canal filled with that allows us to detect what direction our head is moving in?
endolymph
what the otolithic organs?
utricle and saccule
what is the use of the otolithic organs?
help us in detecting linear acceleration and head positioning
what substance does the utricle and saccule contain?
calcium carbonate (CaCo3) crystals attached to hair cells in viscous gel
which organs contribute to vertigo?
the otolithic organs
explain how dizziness comes about?
the endolymph which is responsible for our head direction does not stop spinning at the same as our head so it keeps indicating to our brain we’re still moving even if we’ve stopped
which system is responsible for balance and spatial orientation?
vestibular system
what does the signal detection theory aim?
looks at how we make decisions under conditions of uncertainty discerning between important stimuli and unimportant noise
describe the option in signal detection theory
hit: affirmative action to present signal
miss: no action to present signal
false alarm: perceived signal when no signal was present
correct rejection: correct negative answer for no signal
hit>miss when
there is a strong signal
miss>hit when
there’s a weak signal
d’ stands for and c stands for in signal detection theory
d’: strenght
c: strategy
what is conservative strategy?
always say no when not 100% sure signal is presnt
what is liberal strategy?
always say yes even if there might be false alarms
bottom-up processing
begins with stimulus, stimulus influences what we perceive
top-down processing
uses background knowledge to influence perception
which processing method uses inductive reasoning, is data-driven, and is always correct
bottom-up processing
which processing method uses deductive reasoning, theory-driven and is not always correct?
top-down
What does Gestalt Principles tries to explain?
how we perceive things the way we do
similarity
items similar to each other are grouped together by the brain
pragnanz
realized organized reduced to the simplest form possible
proximity
objects that are close to each other are naturally grouped together rather than things that are farther apart
continuity
lines are seen as following the smoothest part
closure
objects grouped together are seen as a whole
symmetry
the mind perceives objects as being symmetrical and forming around a center point
what is the law of past experiences?
under some circumstances, visual stimuli are categorized according to past experiences.
what is the first part of the eye that light hits?
the cornea
the thing layer of cells that line the inside of the eyelids are called
conjunctiva
this is a space in the eye filled with aqueous humor that helps maintain the shape of eyeballs by allowing mineral and nutrient supply
anterior chamber
this part of the eye is the opening in the middle of the iris and modulates the amount of light able to enter the eyeball
pupil
this muscle gives the color of the eyes and contracts or relaxes to change the size of the ppil
iris
the suspensory ligaments are attached to what
ciliary muscle
these two parts of the eyes are responsible for secreting aqueous humor
ciliary body (ciliary muscle and suspensory ligaments)
area behind the iris filled with aqueous humor
posterior chamber
what is vitreous humor?
jelly-like substance in the vitreous chamber that provides pressure to the eyeballs and supply nutrients to inside the eyeball
the inside of the eyes filled with photoreceptors where ray of light is converted from physical waveform to electrochemical impulse that the brain can accept is called
the retina
a special part of the retina rich in cones and rods is
macula
a special part of the macula rich only in cones is the
fovea
what are cones in the eye
substance that detects color and discern high level of detail in what one is observing
how do rods help the eye?
they detect light
this is a pigmented black network of blood vessels that help nourish the retina
choroid
what gives some animals better night vision?
differently pigmented choroids
the fibrous tissue that covers 5/6th of the eyeball and is an attachment point for muscles is called
the sclera
what is transmission:
the electrical activation of one neuron by another neuron
what is perception?
conscious sensory experience of neural processing
the neural transformation of multiple neural signals into a perception is
processing
this occurs whenever energy is converted from one form to another, namely light to electrical by cones and rods
transduction
in sensation, a neural impulse requires
physical impulse
in the eye, light is converted to neural impulse by
a photoreceptor in the retina
what is light?
light is an electromagnetic wave
what is the range of visible light found in the middle of the EM spectrum?
violet (400nm) to red (700nm)
how many rods does the eye have for night vision?
120 million
what happens when light hit the standardly turned on rod?
the rod goes off, turning on a bipolar cell which turns on a retinal ganglion cell which goes into the optic nerve and enters the brain
how many cones does the eye have?
6-7 million cones
what are the types of cones?
red, green and blue
describe the phototransduction cascade
light hits the rod/cone, cone/rod goes off, bipolar cell goes on, retinal ganglion cell goes on, enters optic nerve, then enters brain
what is the phototransduction cascade?
it is the process of the rods/cones turning from on to off
the axons of the ganglion cells bond together into a long strand called
the optic nerve
what is the trichromatic theory of color?
it states that there are 3 colored cones in our eyes (red, green and blue) that combine to make all the colors we can see
what is the opponent process theory of color vision?
these theory states that we have 4 colors; red, green, blue and yellow, where red and green oppose each other while blue and yellow oppose each other, and between the 2 opponents, only 1 can dominate at a time
what do rods contain that are stacked on top of each other?
optic disks
what type of protein is contained on optic disks in rods?
Rhodopsin, multimeric protein with 7 disks containing a small molecule called 11-cis retinal.
what happens when light reaches the rods and hit the rhodopsin?
it causes retinal in rhodopsin to switch from bent (cis) to straight (trans) form
what marks the beginning of the phototransduction cascade?
when retinal in rhodopsin changes shape causing rhodopsin to change shape
rhodopsin is to rods as __ is to cones
photopsin
there’s a molecule with 3 different parts, namely alpha, beta and gamma attached to rhodopsin. what is it called?
transducin
what happens to attached transducin when rhodopsin changes shape?
it breaks free from rhodopsin and its alpha subunit binds to another disk protein called phosphodiesterase (PDE)
what substance converts cGMP to GMP?
PDE
describe the concentrations of cGMP and GMP in response to light?
cGMP reduces while GMP increases
how are the variants of bipolar cells affected by light after the rods go off?
on center activates and off center inactivates
what happens as the on center of the bipolar cells activate?
the on center of retinal ganglion cells activate as well sending signal to optic nerve to the brain
photopic vision occurs at
high light levels
mesonic vision occurs at
dawn or dusk
scotopic vision occurs at
very low light
what is a photoreceptor?
a specialized nerve that can take light and convert it to neural impulse
which are more sensitive between rods and cones?
rods are 100x more sensitive
what’s the difference between rods and cones?
rods are specialized in detecting light, cones are specialized in colors
rods have slow recovery time, cones have fast recovery time
rods are found mostly in the periphery and cones in the fovea
where the optic nerve connects to the retina and no rods/cones are present is called the
blind spot
explain visual feel processing
ray of light from the left field hits the nasal side of the left eye but the temporal side of the right eye while ray of light in the right field hits the nasal side of the right eye but the temporal side of the left eye
what structure is responsible for color and form?
cones
what structure is responsible for motion?
rods
describe the parvocellular pathway
high spatial resolution (form) and color but low temporal resolution (motion)
describe the magnocellular pathway
high temporal resolution but poor spatial resolution
what is parallel processing?
detecting all forms of an object at the same time (color, form, motion)
what do we need to hear?
- pressurized sound wave (stimuli)
- hair cell (receptor)
where are our hair cells located?
cochlea
what are sound waves?
areas of low and high pressure
what is a wavelength?
how close peaks area
what is the relationship between wavelength and frequency>
smaller wavelength, greater frequency; bigger wavelength, smaller frequency
what is the first thing in the ear sound hits?
outer part-pinna
outline the journey of sound once it hits the pinna
pinna - auditory canal (external auditory meatus) - tympatic membrane (eardrum) -
what 3 bones vibrate once pressurized waves hit the eardrum?
malleus
incus
stapes
what are the 3 smallest bones in the body?
ossicles (malleus, incus, stapes)
stapes is attached to the
oval (elliptical) window
what is the membrane in the middle of the cochlea called?
organ of corti (basilar and tectorial membrane)
cilia
hair cells
what happens as the hair cells move back and fort in the cochlea?
electric impulse is transported by auditory nerve to the brain
what is place theory?
it states that our perception of sound depends on where each component frequency produces vibrations along the basilar membrane
3 general classifications of the ear
outer
middle
inner
outer ear
pinna to tympanic membrane
middle ear
malleus to stapes
inner ear
cochlea and semicircular canals
at the cochlea upper membrane, hair cells are called
hair bundle
each filament of a hair bundle in the at the cochlea upper membrane is called
kinocilium
the tips of each kinocilium are connected by
tip links attached to a K channel gate
what substance gets activated as K enters
Ca which activates spiral ganglion cell which activates the auditory nerve
we can hear frequencies between
20 - 20000 Hz
high frequency sounds activate hair cells at the
base (start of cochlea)
low frequency sounds activate hair cells at the
apex (end of cochlea)
the frequency of sound is mapped to a particular part of the brain called
primary auditory cortex (temporal lobe)
basilar tuning
system used by brain to distinguish different sound frequencies
what is the treatment for people with sensorineural narrow hearing loss )nerve deafness)?
cochlear implants
sensory adaptation?
change over time of receptor to a constant stimulus. down regulation
amplification is
up regulation
somatosensory homunculus
topological map of one’s entire body in the cortex (brain)
somatosensory homunculus information all come to the
sensory strip
the part of the cortex that contains the homunculus is
sensory cortex
proprioception
sense of balance (cognitive)
kinesthesia
sense of movement (behavioral)
ability to sense pain
nociception
ability to sense temp
thermoception
in order for us to sense temperature, we rely on
TrypV1 receptor
what are the 3 types of nerve fibers?
A-beta
A-delta
C
A-beta
fast, thick, covered in myelin
C
small, unmyelinated
A-delta
medium, less myelin
gate control theory of olfaction
non-painful inputs close the gate to painful inputs
affective
experience of emotions
gustation
taste
olfaction
smell
pheromone
chemical signal released by one member of a specie and sensed by another species to trigger an innate response
describe pheromone in animals
specialized part of their olfactory epithelium. accessory olfactory epithelium sends signal to accessory olfactory bulb which then sends signal to brain
within accessory olfactory epithelium is a structure called
vomeronasal system
the vomeronasal system has what 2 types of cells?
basal cells
apical cells
describe the mechanism once molecule comes in and activates basal/apical cells
basal cells send axon through olfactory bulb to glomerulus then mitral/tufted cell and eventually to the amygdala.
amygdala (temporal lobe) is involved with
emotions, aggression, mating, memory, decision-making
why do human rely very little on pheromones compared to animals?
we have vomeronasal organ but no accessory olfactory bulb
what separated the olfactory epithelium from the brain
cribriform plate
above the cribriform plate is the
olfactory bulb
this is a designation point for various sensory olfactory cells that are sensitive to the same molecule
glomerulus
ipsilateral senses
smell
taste
contralateral senses
vision
hearing
touch
label-line theory of olfaction
each receptor responds to a specific stimuli and is directly linked to the brain
vibrational theory
the vibrational frequency of a molecule gives that molecule its odor profile
steric/shape theory
odors fits into receptors similar to a lock-and-key
anosmia
inability to perceive odor
describe the pathway of olfaction
olfactory bulb to amygdala and piriform cortex then to orbitofrontal cortex
the 5 main tastes
sweet
bitter
salty
sour
umami (taste glutamate)
the gustatory system consists of taste receptors found in
taste buds on the tongue
taste buds are contained in structures called the
papillae
name the 3 kinds of taste buds
fungiform (anterior)
foliate (side)
circumvallate (back)
how many receptor cells are in each taste bud that can detect each taste?
5
fungiform papillae
mushroom-shaped structures located on tips and sides of the tongue
foliate papillae
folded structures at back of the tongue on both sides
circumvallate papillae
flat mound structures at back of tongue
filiform papillae
do not contain taste buds but are found all over the tongue
the center of the tongue contains only what kind of papillae/
filiform
tastant
substance that stimulates the sense of taste
gustducin
protein associated with sense of taste
the font 2/3 of the tongue carries signals via
7th cranial nerve via the chords tympani
the posterior 1/3 of the tongue carries signals via the
9th and 10th cranial nerves (glossopharyngeal and vagus)
sweet, umami and bitter cells rely on
GPCR receptors
sour and salty cells rely on
ion channels
where is the first place of integration for taste/smell?
oribofrontal cortex
