Chapter 5: Sensation and Perception Part 2 Flashcards
sound waves
vibrations of the air in the frequency of hearing
auditory system converts:
sound waves into neural impulses
what are the two major qualities of sound waves?
frequency and amplitude
frequency
refers to the number of cycles the wave completes in a certain amount of time, measured in Hz (cycles/second)
amplitude
refers to the strength of a cycle, responsible for detection of “loudness,” measured in decibels (dB)
describe how sound waves are converted to neural impulses:
- sound waves enter ear and deflect tympanic membrane
- vibrations of tympanic membrane strike the ossicles (males, incus, and stapes). stapes hits oval window
- vibrations of the oval window create waves in the cochlea fluid, which deflects the basilar membrane. this movement bends the hair cells
- the hair cells communicate with the auditory nerve, which sends neural impulses to the brain
- signal travels to the brainstem, thalamus, and auditory cortex
- signal travels to auditory association areas in the cortex
tympanic membrane
the ear drum
ossicles
tiny bones in the ear called the malleus (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
brain is set up to integrate information from:
multiple sensory systems
frequency theory
different sound frequencies are converted into different rates of action potentials in our auditory nerves (high frequency=rapid firing)
place theory
differences in sound frequency activate different regions on the basilar membrane
regions along the basilar membrane send inputs to the brain that are encoded according to:
the place along the membrane where the inputs originated
low tones generally associate with:
frequency theory
high tones generally associate with:
place theory
absolute pitch
the ability to recognize or produce any note on a musical scale, associated with differences in brain anatomy
amusia
tone deafness, usually result of damage to the auditory system
list some ways in which sensory auditory systems can adapt:
- ears contract muscles around ear openings so less sound waves enter the ear when exposed to loud sounds
- hair cells of the ear become less sensitive to continuous noises
can sensory receptors of the auditory system by readily replaced?
no, damage can be permanent
cocktail party effect
brain files out sounds that are unimportant (even if it’s loud)
to determine the importance of a particular sound, it’s necessary to:
localize it in space and figure out where it’s coming from
what are some clues used to help localize sound?
- general loudness (loud=closer to us)
- loudness in each ear (ear closer to the sound, hears a louder noise) - associate with high pitch
- timing (sound waves will reach the ear closer to the source first) - associate with low pitch
adjustment of head and bodies to assess the location of sounds allows us to hear:
how sound changes while we’re in different positions
ears are formed and capable of transducing sound waves… when?
before birth
what are the two major causes of deafness?
conduction deafness and nerve deafness
conduction deafness
occurs when there is some occlusion or break in the various processes by which sound is transmitted through the inner ear
nerve deafness
damage or malformation of the auditory nerve to the brain (congenital incidents or deafness from birth is an example)
deafness
lock or lack of hearing, can be partial or total
tinnitus
ringing in the ear
what stimulates the visual system:
electromagnetic radiation (light-photons)
retina
a specialized sheet of nerve cells in the back of the eye containing the sensory receptors for vision-where light produces chemical change that is turned into neural impulses
transduction
process that involves converting stimulus energy into neural impulses that can be interpreted by the brain
photoreceptors (2 types)
the sensory receptor cells 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
blind spot/optic disk
where optic nerves leave retina, no photoreceptors here
fovea
centre of the retina, containing only cones, where vision is most clear
colour is described along 3 dimensions: (a combination of which allows us to see a variety of colours)
hue (colour), saturation (how pure/vivid), brightness (how much light is reflected)
Young-Helmholtz trichromatic theory:
three different receptors for different range of wavelengths of light, different colours perceived due to combination of signals from the photoreceptors
Opponent process theory
colour pairs work to inhibit one another in the perception of colour, information analyzed in terms of antagonistic opponent cloud pairs, results in the activity of the lateral geniculate nucleus in the thalamus
opponent process theory explains negative afterimages which occurs due to:
when stimulus removed, the previously inhibited colour overcompensates and creates an image in the opposite colour
colour blindness/colour vision deficiency
unable to distinguish certain colours
monochromatic
unable to see any colours, see in shades of black and white
visual info leaving the retina travels via the optic nerve to neurons in the:
superior colliculus which communicates with the thalamus, then to the primary visual cortex in the occipital lobe
detection of complex visual stimuli occurs as a result of:
circuitry that involves association areas of visual cortex
association areas are involved with:
higher order processes (thinking & memory)
where is the “what” pathway located?
temporal cortex
where is the “where” pathway located?
parietal cortex
visual agnosia
cannot recognize objects visually, damage to the “what” pathway
prosopagnosia
inability to recognize faces
hemi-neglect
ignore one side of the visual field, usually due to damage of the right hemisphere
damage to the “where” pathway leads to:
ability to recognize objects but inability to locate objects in space
retinal disparity
the slight difference in images processed by the retinas of each eye, provides binocular cue of depth
convergence
binocular cue of depth; the inward movement of the eyes to view objects close to oneself
monocular cues
visual cues about depth and distance that can be perceived using information from only ones eye
perceptual constancies
our top-down tendency to view objects as unchanging, despite shifts in the environmental stimuli we receive
strabismus
eye and movement are uncoordinated, resulting in two different images that are sent to the brain
amblyopia
partial or complete loss of vision due to abnormal development of the brain’s visual cortex (caused by one eye focusing better than the other and loss of visual abilities in the weaker eye)
what is the most common cause of amblyopia?
strabismus
visual impairment
can be congenital or acquired later
kinesthetic sense
receptor cells in muscles respond to shape changes, ex. being squeezed or stretched
vestibular sense
located in semicircular canals of our inner ear-fluid ives with movement, provides info about body movement and location information that matches visual info from eyes (usually)
