ch2: sensation and perception Flashcards
sensation
transduction: conversion of physical, electromagnetic, auditory, and other info from our in and external envir. to electrical signals in the nervous system
performed by receptors in PNS, stimuli sent to CNS in the form of action potentials and neurotransmitter.
RAW SIGNAL
perception
processing of sensation info to make sense of the sig
sensory receptors
neurons that respond to stimuli and tigger electrical signals.
stimuli could be distal (outside, indirect) or proximal (directly interact and affect sensory receptors)
psychophysics
study of the physical nature of the stimuli and the sensations and perceptions that evoke
ganglia
collections of neuron cell bodies found outside the central nervous system
photoreceptors
respond to electromagnetic waves in the visible spectrum (sight)
hair cells
respond to movement of fluid in the inner ear structures
hearing, rotational and linear acceleration
nociceptors
respond to painful or noxious stimuli
somatosensation
thermoreceptors
respond to chgs in temp
thermosensation
osmoreceptors
respond to the osmolarity of the blood
water homeostasis
olfactory receptors
respond to volatile compounds
smell
taste receptors
respond to dissolved compounds
taste
absolute threshold/limina
minimum of stimulus energy that is needed to activate ta sensory system
threshold in SENSATION NOT PERCEPTION
a stimulus below the absolute threshold will not be transducer and thus never reaches CNS
Subliminal Perception
perception of a stimulus below a given threshold
the threshold of conscious perception.
a stimulus below the threshold of conscious perception arrives at the CNS, but doesn’t reach the higher order brain regions that control attention and consciousness
discrimination testing=psychophysical discrimination testing
participant is presented with a stimulus this is varied slightly, and asked to identify difference.
until a change is noticed, the chg btw the two is increased
difference threshold=just-noticeable difference (jnd)
minimum difference in magnitude between 2 stimuli before one can perceive difference
webers law
constant ration between chgs in stimulus magnitude needed to produce a jnd and the magnitude of the original stimulus.
signal detection theory
perception of stimuli is affected by non sensory factors, experiences (memory), motives, and expectations.
focuses on the chgs in out perception of the same stimuli depending on in and external context
response bias
tendency of subjects to systematically respond to a stimulus in a particular way due to non sensory factors
catch trials- signal present
noise trails- signal not present
subject could respond in such a way, creating 4 diff situas
adaptation
signal detection of stimulus can change over time thru adaptation
what entire lobe of the brain is devoted to vision?
occipital lobe (out of Fpot)
eye
specialized organ used to detect light in the form of photons
sclera
white of the eye
most of the exposed potion the eye is covered by this thick structural layer
provides structural support
does not cover the front most part for he eye, the cornea
choroidal vessels
a complex intermingling of blood vessels between the sclera and retina
one of two blood vessels that supplies the nutrients to the eye
retinal vessels
one of two blood vessels that supplies the nutrients to the eye
retina
innermost layer of the eye
detects images
contains the actual photoreceptors that transducer light into electrical information the brain can process
cornea
clear, domelike window in the front of the eye
light first passes through this
gathers and focuses the incoming light
anterior chamber
lies in front of the iris, allows passage of light
posterior chamber
lies between the iris and the lens, allows passage of light
dilator pupillae
muscle that is part of the iris that opens pupil under sympathetic stimulation
constrictor pupillae
muscle that is part of the iris that constrict pupil under para sympathetic stimulation
choroid
continuous with the iris
ciliary body
produces aqueous humor that bathes the front part of the eye before draining into the canal of schlemm
accommodation of the lens
ciliary muscle
component of the ciliary body
contracts under parasympathetic control
-as it contracts, it pulls on the suspensory ligaments and changes the shape of the lens (this=accommodation)
vitreous
transparent gel that supports the retina
retina
back fo the eye
is like a screen consisting of neural elements and blood vessels
funct: convert incoming photons fo light to electrical signals, detects images
part of the CNS, developed as outgrown of brain tissue
made up of 6 mil cones and 120 mil rods
duslexity = duplicity theory of vision
retina contains 2 kinds of photoreceptors
- specialized for light and dark detection
- specialized for color detection
cones
used for color vision and to sense fine details
most effective in bright light
come in short=S=best absorb blue,
medium=M=green,
long=H=red
rods
more effective in low light
only allow sensation of light and dark because they contain a single pigment=rhodopsin
macula
central section of the retina
has a high concentration of cones
centermost point: fovea: contains ONLY cones
- as you move away from fovea, [rod]^ while [cone]v
- so visual activity is best at fovea, most sensitive to normal daylight vision (more cones->better w light)
bipolar cells
highlight gradients between adjacent rods or cones
synapse with ganglion cells
ganglion cells
group together to form the optic nerve
synapse with bipolar cells
amacrine and horizontal cells
receive input form multiple retinal cells in the same area before the info is passed on to ganglion cells
can accentuate slight difference between the visual info in each bipolar cells
important for edge detection
increase our perception of contrasts
visual pathways
physical anatomical connections between the eyes and the brain and the flow of visual information along these connections
optic chiasm
first sig event that occurs after a final travels thru the optic nerves toward the brain
the fibers form the nasal half of each retina cross paths and carry the temporal visual field from each eye
the temporal fibers (from nasal) don’t cross, so all fivers corresponding to the left visual field from both eyes project into the right side of the brain and all the fibers corresponding to the right visual field from both eyes project into the left side of the brain
- these pathways= OPTIC TRACTS
lateral geniculate nucleus (LGN) of the thalamus
from the optic chasm, the info can go to here of several, thru radiation in the temporal and parietal lobes to the visual cortes in the occipital lobe
superior colliculus
controls some responses to visual stimuli and reflexive eye movements
parallel processing
ability to simultaneously analyze and combine info regarding color, shape, and motion, integrate this info to creat a cohesive image of the world
calls on memory sys to compare a visual stimulus to past experiences to help determine the objects identity
also correlates in neuroscience called feature detection
parvocellular cells
detects shape by having high color spatial resolution (permit us to see very fine detail when thoroughly examining an object)
can only work in slow moving objects because they have very low temporal resolution.
magnocellular cells
detects motion by having high temporal resolution, but have low spatial resolution, so much of the rich detail of an object can no longer be seen once it is motion
provide, blurry, but moving image of an object
lens
refracts the incoming light to focus it on the retina
structure of visual pathway, form where light enters the cornea to the visual projection areas in the brain
cornea–> pupil–> lens–> vitreous–> retina (rods and cons–>bipolar cells–> ganglion cells)–> optic nerve–> optic chasm–> optic tract–> lateral geniculate nucleus (LGN) of thalamus–> radiations thru the parietal and temporal lobes–> visual cortex (occipital lobe)
pinna=auricle
cartilaginous outside part of the ear
main func: channel sound waves into external auditory canal
external auditory canal
directs sound waves tot the tympanic membrane (eardrum)
tympanic membrane (eardrum)
vibrates in phase with the incoming sound waves
the frequency of the sound wave determines the rate at which the eardrum vibrates, lower sounds have greater intensity
divides outer ear from middle ear
intensity
corresponds to an increased amplitude of this vibration
ossicles
smaller bonds in the body, in the middle ear
help transmit and amplify the vibrations from the tympanic membrane to the inner ear
malleus (hammer)
affixed to the tympanic memebrane
acts on the incus (anvil) which acts on the stapes (stirrup)
eusatian tube
helps equalize pressure between the middle ear and the environment
middle ear is connected to the nasal cavity via this
bony labyrinth
contains the cochlea, vestibule, and semicircular canals
-these structures are continuous with e/o and are mostly filled by the membranous labyrinth, which is bathed by a potassium rich fluid called endolymph
inner ear sits within this
membranous labyrinth
bathed by a potassium rich fluid called endolymph
suspended within the bony labyrinth by a thin layer of another fluid called perilymph (simultaneously transmits vibrations from the outside world and cushions the inner ear structures)
cochlea
spiral shaped organ divided into three parts called scalae
scalae
all threee run the entire length of the cochlea
the middle houses the actual hearing apparatus= organ of corti (rests on a thin flexible membrane=basilar membrane)
the other two: filled with perilymph, surround the hearing apparatus and are continuous with the oval and round windows of the cochlea
organ of corti
rests on a thin flexible membrane=basilar membrane
composed of thousands of hair cells with are bathed in endolymph
on top of it, is a relatively immobile membrane= tectorial membrane
round window
a membrane-covered hole in the cochlea
permits the perilymph to actually move within the cochlea
auditory (vestibulocochlear) nerve
hair cells in the organ of court convert the physical stimulus into an electrical signal, which is carried by this
vestibule
portion of the bony labyrinth that contains the utricle and saccule, which are sensitive to LINEAR acceleration, so are used as a part of the balancing apparatus
contain modified. hair cells covered with otoliths, which rests that motion as the body accelerates, which would ben and stimulate the underlying hair cells which send a signal to the brain
semicircular canals
three are sensitive to rotational acceleration.
arranged perpendicularly to e/o and each ends in a swelling called an ampulla, where hair cells are located.
when head rotates, endolymph in the semicircular canal resists, bending underlying hair cells, send signal to brain
auditory pathways
most sound info passes thru the vestibulocochlear nerve to brainstem–> medial geniculate nucleus (MGN) of the thalamus–> auditory cortex in temporal lobe for sound processing
some info is also sent to the superior olive, which localizes the sound and the inferior colliculus, which is involved int eh startle reflex, and helps keep the eyes fixed on a point when the head is turned (vestibule-ocular reflex)
stereocilia
long tufts on the top surface of hair cells
help open the ion channels as the swap back and forth, causing receptor potential
place theory
states the at the location of a hair cell on the basilar membrane determines the perception of the pitch when that hair cell is vibrated
linear acceleration
detected by the utricle and saccule
rotational acceleration
detected by the semicircular canals
list the structures of the auditory pathway, from where sound enters the pinna to the auditory projection areas in the brain
pinna –> esternal auditory canal –>tympanic membrane –> malleus –>incus –> stapes –>oval window –>perilymph in cochlea –>basilar membrane –>hair cells –> vestibulocochlear nerve –>brainstem –>medial geniculate nucleus (MGN) of thalamus –>auditory cortex (temporal lobe)
how does the organization of the cochlea indicate the pitch of an incoming sound
the basilar membrane is tonotopically organized: high-pitched sounds cause vibrations at the base of the cochlea, whereas low pitch sounds cause vibrations at the apex of the cochlea
olfactory chemoreceptors (olfactory nerves)
localized in epithelium in the upper part of the nasal cavity chemical stimuli must bind to their respective chemoreceptors to cause a signal
SENSITIVE TO VOLATILE OR AEROSOLIZED COMPOUNDS
pheromones
affect animals social foreign and sexual behavior
secreted by one person or animal, and once bonded with chemoreceptors, compel or urge another to behave a specific way
olfactory pathway to the brain
inhaled thru nasal passages –> contact the olfactory nerves/chemoreceptors in olfactory epithelium–> send signals to olfactory bulb–> olfactory tract –> higher regions of the brain, including the limbic system
five basic tastes
sweet, sour, salty, umami (savory), bitter
taste chemoreceptors
SENSITIVE TO DISSOLVED COMPOUNDS
the receptor for tase are groups of cells called taste buds, found on bumps on tongue called papillae
last information traveling pathway
tastebuds to brainstem, to taste center in thalamus before traveling to higher order brain regions
somatosensation
“touch” but is actually more complex: PRESSURE, VIBRATION, TEMPERATURE, AND PAIN
five different receptors that receive tactile info
- pacinian corpuscles
- meissner corpuscles
- merkle cells (discs)
- ruffini endings
- free nerve endings
pacinian corpuscles
respond to deep pressure an dvibration
meissner corpuscles
respond to light touch
merkle cells (discs)
respond to deep pressure and texture
ruffini endings
respond to stretch
free nerve endings
respond to pain and temperature
somatosensation transaction
receptors–>send signal to CNS–> somatosensory cortex in parietal lob
two point threshold
min distance necessary between two points of stimulation on the skin such that the point swill be felt as two distinct stimuli
physiological zero
normal temperature of skill (86- 97)
nociceptors
sensory receptors that send signals that may lead to pain perception, which is a part of the somatosensory system
gate theory of pain
proposes that there is a special “eating” mech that can turn pain signals on or off, affecting whether or not we perceive pain
kinesthetic sense=proprioception
ability to tell where ones body is in space
bottom-up (data-driven) processing
object recognition by parallel processing and feature detection
brain takes the individual sensory stimuli and combines them together to create a cohesive images before determining wha the object is
helps discriminate slight differences between similar objects
top-down (conceptually driven) processing
driven by memories and expectations that allow the brain to recognize the whole object and then recognize the components based on these expectations
allows us to quickly recognize objects without needing to analyzed their specific parts
helps in recognizing objects form past
perceptual organization
ability to use top down and bottom up in tandem with all fo the other sensory clues about an object to creat a complete idea/pic
depth perception
rely on both monocular and binocular cues (one or both eyes)
monocular: relative size, convergence of parallel lines at a distance, position in visual field, lighting and shading
binocular: slight diff in images projected on the two rentals and tangle required btwn the two eyes to bring object in focus
form
usually determined thru parallel processing and feature detection, and the motion o fan object is perceived thru magnocellular cells
constancy
refers to the idea that we perceive certain characteristics of objects to remain the same, despite differences in the environment
gestalt principles
ways for the brain to infer missing parts of a picture when a picture is incomplete
governed by law of prägnanz
there are 5 proximity similarity good continuation subjective contours closure
law of proximity
elements close to one another tend to be perceived as a unit
law of similarity
similar objects tend to be grouped together
law of good continuation
elements that appear to follow in the same pathway tend to be group together
subjective contours
perceiving contours and therefore, shapes that are not actually present in the stimulus
law of closure
when a space is enclosed by a couture, it tends to be perceived a a complete figure
law of prägnanz
perceptual organization will be as regular, simple, and symmetric as possible
endolymph is found in the …
membranous labyrinth
mnemonic: membrane: endocytosis idk?
perilymph is found in the …
bony labyrinth.
mnemonic: Per… bo…
