Ch. 3- Sensation and Perception Flashcards
what is sensation?
physical reality of signals that our sensory organs pick up and send to be processed in the nervous system
what is perception?
how our brain interprets signals from our sensory organs
what are sensory receptors?
specialized dendrites of sensory neurons that respond to physical stimuli via action potentials to the CNS
what are nerves?
bundles of axons of sensory receptor dendrites
what are ganglia?
collections of neuronal cell bodies
what are the 4 types of properties that get relayed to the CNS?
location (where), modality (what type), intensity (how much), and duration (how long)
what is the differnce between exteroceptors and interoceptors?
exteroceptors = receive stimuli from the outside world
interoceptors = receive stimuli from inside the body
what do photoreceptors sense?
light
what do mechanoreceptors sense?
sound, acceleration, touch (mechanical)
what do chemoreceptors sense?
taste, smell (chemicals)
what do baroceptors sense?
pressure (type of mechanoreceptor)
what do proprioceptors sense?
body position (kinesthetic sense)
what do nociceptors sense?
pain (cuts, burns, chemicals)
what do osmoceptors sense?
concentration (ie. in blood)
what do olfactory receptors sense?
smell
what do gustatory receptors sense?
taste
what do hair cells sense?
pressure signals in the inner ear (convert to action potentials)
what do thermoreceptors sense?
variation in temperature
what are proximal vs distal stimuli?
proximal stimuli are the stimuli that directly interact with you
distal stimuli are causing something else to act as a proximal stimulus.
ie. tree = distal stimulus, causing light rays (proximal stimulus) to directly interact with your eyes.
absolute threshold
the level of intensity a stimulus has to have in order for your sensory neurons to pick it up
threshold of conscious perception
the threshold a stimulus must pass in order for us to consciously perceive it
in between absolute threshold and threshold of conscious perception = ?
you’ll experience whatever the thing is, but your brain won’t take up that information.
just-noticeable difference
smallest change in magnitude of a stimulus that we can perceive as being different
psychophysical discrimination testing
testing whether participants can tell the difference between the two stimuli and then link that to the actual physical properties of the stimuli being studied
Weber’s law
for any sensory input, the just-noticeable difference will be a constant proportion of the original input.
does Weber’s law hold at the extremes?
not really, if there’s not much difference in how you interact with them (ie. weights on the scales of milligrams or on the scale of thousands of pounds would be very difficult to distinguish)
signal detection theory
our brain sorts through stimuli to try to accurately identify what we need to pay attention to
signal detection theory: what is a hit?
we correctly perceive a stimulus that is present
signal detection theory: what is a miss?
we incorrectly do not perceive a stimulus that is present
signal detection theory: what is a false alarm or false positive?
we incorrectly perceive a stimulus that is NOT present
signal detection theory: what is a correct rejection?
we correctly do not perceive a stimulus that is not present
sensory adaptation
we become used to stimuli and start to ignore them
tonic receptors
some receptors that adapt slowly to stimuli and send action potentials as long as the stimulus is present (ie. pain receptors)
phasic receptors
receptors that send a quick burst of action potentials in response to a stimulus and then stop
Gestalt laws
principles describing how we integrate stimuli into consciously perceived shapes
principle of proximity
our brains group objects by proximity to each other
principle of similarity
our brains group objects by similarity
principle of good continuation
our brains perceive overlapping/intersecting objects as the most continuous line possible
principle of closure
our brains fill in the gaps of broken up outlines
principle of symmetry
our brains group symmetrical objects together more than non-symmetrical objects
law of Pragnanz
our brains tend to try to group things into a cohesive unit instead of processing them as random parts
what part of the eye turns wavelengths of light into action potentials to send to the brain?
the retina
where is the retina located?
in the back of the eye
what component of vision do cones deal with?
color and fine detail (blue, green, and red)
what is the fovea?
a small central pit in the center of the macula in the retina, only contains cones
what component of vision do rods deal with?
light and movement (no fine detail)
relatively, how many cones and rods are there in the eye?
20 rods for every 1 cone
where is rhodopsin mostly concentrated in?
rods
where are rods located in the eye?
away from the retina, making peripheral vision best at night
what is the first part of the eye that light passes through?
the cornea
where are the lens and cornea located in the eye?
near the front of the eye
what is the cornea for?
protecting the rest of the eye, and focusing incoming light rays
what is the lens for?
focusing light
what is accommodation in the eye?
using tiny ligaments to change the focus of the lens to see objects at various distances
what is dark adaptation?
the way that rods take awhile to activate and become useful after you’ve been in the light for awhile
what is the pupil?
the black center of the eye that lets light into the eye
what is the iris?
the colored ring of the eye that blocks unneccessary light and is connected to dilator and constrictor pupillae muscles
what is the ciliary muscle?
part of the ciliary body, adjusts the lens via the suspensory ligaments
where is the division between the anterior and posterior chambers?
the lens divides the two chambers
what space contains the aqueous humor?
the anterior chamber
what space contains the vitreous humor?
the posterior chamber
what is the choroid?
a layer behind the retina that has melanin, supplies the retina with blood and absorbs excess light
what is the sclera?
the outermost layer of the eye (the white stuff)
what is the conjuctiva?
a thin, translucent film that’s on the very outermost layer of the cornea and sclera, a thin layer of epithelial tissue that lubricates and protects the eye
what is the path a signal takes from the retina to the optic nerve?
cones and rods in retina -> horizontal cells -> bipolar cells -> amacrine cells -> ganglion cells (optic nerve)
the right sides of your eyes’ field of vision traces back to which hemisphere of the brain?
the left side
the left sides of your eyes’ field of vision traces back to which hemisphere of the brain?
the right side
where do the halves of the optic nerves cross to their correct sides of the brain?
the optic chiasm
what parts of the optic nerve get moved across to the correct sides of the brain?
the nasal sides (whatever’s reflecting on the inner halves of the retinas)
what parts of the optic nerve don’t cross over to the other side of the brain?
the temporal sides (whatever’s reflecting on the outer halves of the retinas)
what is the optic tract?
the bundle of axons carrying visual information
what structure does the optic tract run through?
the lateral geniculate nucleus (LGN), which is in the thalamus.
what does the lateral geniculate nucleus (LGN) do?
it relays information from the retinas to the superior colliculus
what is the superior colliculus?
receives signals from the lateral geniculate nucleus (LGN), controls the visual startle response, and controls conscious visual perception
what types of neurons does the lateral geniculate nucleus (LGN) have?
magnocellular neurons and parvocellular neurons
what are magnocellular neurons and what do they do?
they are the big neurons that detect motion
what are parvocellular neurons and what do they do?
they are the small neurons that detect details
what kind of relationship is there between spatial and temporal resolution?
you can have one but not both (spatial = detail, temporal = movement)
motion parallax
object closest to us appear to move faster, objects fathest from us appear to move slower
feature detection
able to grab several detail categories at once (ie. shape, color, timing, motion)
parallel processing
integrating multiple detail categories at once (ie. shape, color, timing, motion)
serial processing model
consciously looking at one thing at a time and analyzing it in order
what is the transduction pathway for sound?
hair cells -> vestibulocochlear nerve
where are hair cells located?
inner ear, in the organ of Corti (layer cake organ with hair cells in the middle).
what are the structures contained in the outer ear?
the pinna/auricle, earlobe, and the auditory canal up to the eardrum.
what are the structures contained in the middle ear?
the eardrum/tympanic membrane, the tympanic cavity, the ossicles (malleus, incus, and stapes), the oval window, and the start of the Eustachian tube.
what are the structures contained in the inner ear?
the bony labyrinth (membranous labyrinth, endolymph, perilymph), the cochlea (snail shell in 3 layers/scalae + organ of Corti), the vestibulocochlear nerve, semicircular canals (+ ampulla), and the vestibule (utricle, saccule, otoliths)
place theory of hearing
the brain infers information about the pitch of a sound based on which hair cells are sending signals
what is somatosensation?
sensations of the body
are nerves in the skin evenly distributed?
no, there are more in certain places.
what is the two-point threshold?
the minimum distance between two points that are stimulated at the same time on the skin that can be perceived as two separate stimuli
physiological zero
the baseline temperature of our skin (about 29-32C)
what is the process of processing taste information?
taste center (thalamus) -> gustatory complex
what is the process of processing smell information?
olfactory bulb -> olfactory tract
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