ch 5- sensation and perception Flashcards
sensation
using our sensory receptors to detect a stimuli
perception
the conscious recognition and identification of a stimulus
Sensory System
-Olfactory (smell)
-Somatosensory (touch, heat, pain)
-Gustatory (taste)
-Auditory (hearing)
-Visual (sight)
What are the physical stimuli for each of these?
Physical Stimuli
-Odorants (airborne chemicals)
-Pressure or damage to the skin
-Chemicals (typically in food)
-Sound waves
-Light (photons)
sensory receptor cells
specialized cells that convert a specific form of environmental stimuli to neural impulses
sensory transduction
the process of converting a specific form of environmental stimuli to neural impulses
threshold
the point that the magnitude/intensity of a stimulus initiates a neural impulse
absolute threshold
the minimal stimulus needed for detection by an individual 50% of the time
difference threshold or “just noticeable difference”
the minimal difference between two stimuli necessary for the detection between the two
signal detection theory
theory that the response to a signal in every situation depends on an individual’s ability to differentiate between the signal and the noise, and on their response criteria (would you taste old milk or chicken to see if it has gone bad?)
Olfactory adaptation
our ability to detect certain odours fades when we are in the presence of that odour for a prolonged period of time
bottom-up processing
perception that occurs by taking in stimuli, converting them to neural impulses and then moves into more complex brain regions
top-down processing
perception led by cognitive processes such as expectations or memories
perceptual set
our “readiness” to interpret a certain stimuli
–> picture of a UFO will be perceived differently based on beliefs about UFOs
–> a food may taste different if someone told you if was snake for example
perception involves both — and — processing at the same time
bottom-up and top-down
olfactory sense
our sense of smell
gustatory sense
our sense of taste
odorants
airborne chemicals detected as odours
olfactory receptor neurons
sensory receptor cells that convert chemical signals from odourants to neural signals
–> sensory receptors located on cilia of olfactory receptor neurons
describe how olfactory receptor neurons work
specific odours have specific receptors. When enough odourant molecules bind to receptors, action potential fires. The cell will stop responding to the odourant molecule unless given a chance to recover so it can fire again
papillae
bumps on the tongue that contain clumps of taste buds
taste buds
clusters of sensory receptor cells that convert chemical signals in food into neural signals
olfactory bulb
the first region where olfactory info reaches the brain on its way from the nose
ageusia
inability to taste
hyposmia
reduced ability to detect odours
anosmia
inability to detect odours
how are migraines and seizures related to smell and taste?
-a specific odour can trigger a migraine
-reflex epilepsy: a type of epilepsy where a seizure occurs after exposure to a certain odour
free nerve endings
sensory receptors that convert stimuli into touch, pressure or pain impulses
Meissner’s corpuscles
sensory receptors that convert physical stimuli about sensory touch on the fingertips, lips, and palms.
Merkel’s disks
sensory receptors that convert information about light to moderate pressure on the skin
Ruffini’s end-organs
sensory receptors that respond to heavy pressure and joint movement
Pacinian corpuscles
sensory receptors that respond to vibrations and heavy pressure.
gate control theory of pain
theory that certain patterns of neural activity can close a “gate” to keep pain information from travelling to parts of the brain where it is perceived
endorphins and enkephalins
chemicals that belong to a naturally occurring class of opiates that reduce pain in the nervous system.
tympanic membrane
the ear drum
Vibrations of the tympanic membrane set in motion a series of three tiny bones or ___
ossicles, called the maleus (hammer), incus (anvil), and stapes (stirrup).
oval window
a membrane separating the ossicles and the inner ear, deflection of which causes a wave to form in the cochlea.
cochlea
fluid-filled structure in the inner ear; contains the hair cells.
basilar membrane
structure in the cochlea where the hair cells are located
hair cells
sensory receptors that convert sound waves into neural impulses.
tonotopic map
representation in the auditory cortex of different sound frequencies.
absolute pitch “perfect pitch”
the ability to recognize or produce any note on a musical scale
tinnitus
ringing in one or both ears
retina
a specialized sheet of nerve cells in the back of the eye containing the sensory receptors for vision.
transduction
process that involves converting stimulus energy into neural impulses that can be interpreted by the brain.
photoreceptors
sensory receptors for vision, located in the retina
rods
photoreceptors most responsive to levels of light and dark
cones
photoreceptors responsive to colours
optic nerve
the bundle of axons of ganglion cells that carries visual information from the eye to the brain
fovea
centre of the retina, containing only cones, where vision is most clear
retinal disparity
the slight difference in images processed by the retinas of each eye
convergence
inward movement of the eyes to view objects close to oneself
monocular cues
visual clues about depth and distance that can be perceived using information from only one eye
perceptual constancies
our top-down tendency to view objects as unchanging, despite shifts in the environmental stimuli we receive
