Sensation and Perception Flashcards
Transduction?
conversion of physical, electromagnetic, auditory, and other information from our internal and external environment to electrical signals in the NS
Perception?
refers to the processing of this information to make sense of its significance
distal stimuli?
stimuli that originate outside of the body (ex. camp fire is a distal stimulus)
proximal stimuli?
react directly with sensory receptors
ganglia
collections of neuron cell bodies found outside the central nervous system
threshold
the minimum amount of a stimulus that renders a difference in perception
absolute threshold
the minimum of stimulus energy that is needed to activate a sensory system
subliminal perception
refers to the perception of a stimulus below a given threshold (can use discrimination testing to detect the difference between two stimuluses)
difference threshold/ just-noticeable difference (jnd)
minimum difference in magnitude between two stimuli before one can perceive a difference
Weber’s Law
there is a constant ratio between the change in stimulus magnitude needed to produce a jnd and the magnitude of the original stimulus (weber’s law appears to be accurate for all sensory modalities, except at the extremely high and low ends of each range)
signal detection theory
focuses on the changes in our perception of the same stimuli depending on both internal and external context
response bias
refers to the tendency of subjects to systematically respond to a stimulus in a particular way due to non-sensory factors
catch trials
trails in which the signal is presented
noise trials
trials in which the signal is not presented
hits
subject correctly perceives the signal
misses
subject fails to perceive a given signal
false alarm
subject seems to perceive a signal when none was given
correct negatives
subject correctly identifies that no signal was given
adapation
decrease in response to a stimulus over time
sclera
white of the eye
choroidal vessels
blood vessels between the sclera and the retina
retinal vessels
The retinal blood vessels are the central retinal artery and vein, and their branches.
cornea
clear, dome-like window in front of the eye, where light first passes through
iris
colored part of the eye
anterior chamber
lies in front of the iris
posterior chamber
between the iris and the lens
dilator pupillae
opens the pupil under sympathetic stimulation
constrictor pupillae
constricts the pupil under parasympathetic stimulation
lens
lies right behind the iris and helps control the refraction for the incoming light
retina
back of the eye, duplexity or duplicity theory of vision, two kinds of photoreceptors –> those specialized for light and those specialized for color detection
rods
sense light and dark, all contain a single pigment called rhodopsin
cones
cones are for COLOR vision, macula has a high concentration of cones, centermost point has only fovea (contains only cones)
bipolar cells
rods and cones connect with these cells, bipolar cells synapse with ganglion cells, form optic nerve
amacrine and horizontal cells
receive input from multiple retinal cells, info is passed on to ganglion cells
optic chiasm
fibers from the nasal half (closer to the nose) of each retina cross paths, once they leave the optic chiasm its called the optic tracts
lateral geniculate nucleus (LGN)
relay center in thalamus for the visual pathway
occipital lobe
for vision, visual cortex
superior colliculus
when there is a loud, sudden sound, the superior colliculus aligns the eyes with the likely stimulus, gives deer in the headlights response
parallel processing
ability to simultaneously analyze and combine information regarding color, shape, and motion
feature detection
visual pathway contain cells specialized in detection of color, shape, or motion
magnocellular cells
cells specialize in motion detection, have very high temporal resolution
parvocellular cells
shape is detected by parvocellular cells, have very high color spatial resolution, low temporal resolution
other sense that the ear helps with besides hearing?
rotational and linear acceleration (vestibular sense)
tympanic membrane
eardrum
3 small bones in ear
Malleus–> incus–> stapes
What helps equalize pressure in the middle ear and the environment?
Eustachian tube
Inner ear parts
Within the bony labyrinth, contain the cochlea, vestibule, and semicircular canals…continuous with each other, mostly filled with the membranous labyrinth, bathed in potassium rich fluid called endolymph
Cochlea
spiral shaped organ, divided into scalae, organ of Corti, basilar membrane; organ of Corti is composed of thousands of hair cells, bathed in endolymph
Round window
a membrane covered hole in the cochlea, permits the perilymph to actually move within the cochlea
Vestibule?
contain the utricle and saccule, sensitive to linear acceleration
Semicircular canals are sensitive to what type of acceleration?
rotational acceleration
Auditory pathways in the brain?
Vestibulocochlear nerve–> brainstem–> Medial geniculate nucleus (MGN)–> auditory cortex in the temporal lobe for sound processing, some is sent to the superior olive, localizes the sound; other is sent to the inferior colliculus, involved in the startle reflex
sterocilia
hair cells in the ear, help with sound
place theory
the location of a hair cell on the basilar membrane determines the perception of pitch when that hair cell is vibrated, cochlea is tonotopically organized
olfactory chemoreceptors
olfactory nerves, located in the olfactory epithelium in the upper part of the nasal cavity, lots of specific chemoreceptors
pheromones
secreted by one person or animal and impact another to act in a specific way, role in social, foraging, and sexual behavior
olfactory pathway to the brain?
odor molecules are inhaled –> receptor cells are activated, send signals to the olfactory bulb, relayed via the olfactory tract to higher regions of the brain including the limbic system
papillae
little bumps on the tongue where taste buds/receptors for taste are found
somatosensation
sense of touch, somatosensory cortex is in the parietal lobe; 4 touch modalities: pressure, vibration, pain, and temp.
Pacinian corpuscles
respond to deep pressure and vibrations
Meissner corpuscles
respond to light touch
Merkel cells (discs)
respond to deep pressure and texture
Ruffini endings
respond to stretch
Free nerve endings
respond to pain and temperature
two-point threshold
the minimum distance necessary between two points of stimulation on the skin such that the points will be felt as two distinct stimuli
Proprioception
kinesthetic sense, ability to tell where one’s body is in space
bottom-up processing
refers to object recognition by parallel processing and feature detection
top-down processing
driven by memories and expectations that allow the brain to recognize the whole object and then recognize the components based on these expectations
perceptual organization
refers to the ability to use these two processes, in tandem with all the other sensory clues about an object, to create a complete picture or idea
depth perception
can rely on both monocular and binocular cues (processes that involve one or both eyes, respectively),
Gestalt principles
ways for the brain to infer missing parts of a picture when a picture is incomplete
law of proximity
elements close to one another tend to be perceived as a unit
law of similarity
objects that are similar tend to be grouped together
law of good continuation
elements that appear to follow in the same pathway tend to be grouped together
subjective contours
perceiving contour sand therefore shapes that are not actually present in the stimulus
law of closure
when a space is enclosed by a contour it tends to be perceived as a complete figure
law of pragnanz
perceptual organization will always be as regular, simple, and symmetric as possible
