Vision & Hearing Flashcards
What is sensation?
Registration of physical stimuli from the environment by the sensory organs
What is perception?
subjective interpretation of sensations by the brain
What do sensory receptors do?
convert sensory energy into neural activity
What are receptive fields?
Region of sensory space in which a stimulus modifies a receptor’s activity
Are sensory receptors evenly distributed across the body?
no
Why are your fingers more sensitive than your elbows?
sensory density is higher in figners
What is a topographic map?
neural spatial representation of the body or areas of the sensory world perceived by the sensory organs
How is info passed from visual receptors to brain?
visual receptors to thalamus to cerebral cortex
How is info passed from auditory receptors to brain?
auditory receptors to hindbrain to midbrain to thalamus to cerebral cortex
How is info passed from somatosensory receptors to brain?
somatosensory receptors to spinal cord to brainstem to thalamus to cerebral cortex
What is the cornea?
clear outer layer of eye
What is the function of the iris?
opens and closes to let more or less light into the pupil
What is the function of the lens?
focuses light
What is the function of the retina?
converts light to neural signals
What is the fovea?
small depression in the center of the retina where there is only cones (highest visual acuity)
What is the blind spot?
the optic disc, where the optic nerve connects to eyes, no receptors
What are the types of photoreceptors?
cones and rods
What are some traits of rods?
work well in dim lighting, lower visual acuity, colour blind more in periphery
What are some traits of cones?
do not work in dim light, higher visual acuity, colour sensitive, more in center
What are the types of neurons in the retina?
bipolar cell, horizontal cell, amacrine cell, retinal ganglion cell
What are two types of retinal ganglion cells? (RGC)
magnocellular cell and parvocellular cell
What is the function of M-cell?
receives input mostly from rods, sensitive to light/moving stimuli
What is the function of P-cell?
receives input mostly from cones, sensitive to colour
What is the optic chiasm?
where optic nerves from each eye cross, axons from the inside (nasal) half of the retina will cross to other side, axons from the outside (temporal) will stay on same side
Info from the left side of the visual field goes where? What about right side?
left goes to right side of brain, right goes to left side of brain
How does the geniculostriate system get visual info to the visual part of the brain?
retinal projections to lateral geniculate nucleus (LGN) to visual cortex
How does the tectopulvinar system get visual info to the visual part of the brain?
retinal projections to superior colliculus to thalamus (pulvinar) to parietal/temporal visual areas
What are the 3 routes to the visual brain?
geniculostriate, tectopulvinar, retinohypothalmic
What is the how pathway?
dorsal visual stream, from occipital cortex to parietal cortex
What is the what pathway?
ventral visual stream, from occipital cortex to temporal cortex
What is V1?
primary visual cortex
What is visual agnosia?
an impairment in recognizing visually presented objects
What is the topographic organization of V1?
center of visual field it the back, top part of visual field is represented in lwoer part of occipital lobe, peripheral parts are located more anteriorally
What is monocular blindness?
blind in one eyes
What is homonymous hemianopia?
visual deficit of visual field in same half of each eye, caused by injury/stroke
What is quadrantanopia?
visual loss in 1/4 of visual field
What is scotoma?
a blind spot in visual field
What do we interpret the frequency of sound waves as?
pitch
What is the frequency range humans can hear?
20-20000 Hz
What do we interpret the amplitude of sound waves as?
how loud/intense a noise is
WHat does amplitude refer to?
Reflects the magnitude of change in air molecule density (how tall is wave)
What does the auditory system do?
turns vibrations in the air and turns them into vibrations in fluid that is eventually turned into electrical signals
What is timbre?
the quality of different sounds w/similar frequency/amplitude
Do non-human primates prefer music over other sounds?
no
Where is language vs music located in the brain?
left hemisphere is typically language and right is music
What is nonspeech and nonmusical noise produced at about five segments perceived as?
a buzz (normal speech is 8-10)
What are the types of bilingualism?
compound bilingualism (young child/toddler), coordinate bilingualism (older child/teen), subordinate bilingualism (adult)
What is the pinna?
part of ear that we can see, collects sound waves and sends to external ear canal
Sound waves are amplified and sent to the eardrum, what happens next?
ear drum vibrates which in turn vibrates ossicles
What are the auditory ossicles?
small bones in the middle ear that transmit vibrations from outer to inner ear (malleus, incus, stapes)
What do the ossicles transmit the vibrations to?
the oval window, which sends waves through the cochlear fluid
After vibrations are turned into waves in the cochlear fluid what happens?
basilar and tectorial membranes bend which causes the cilia of inner hair cells to bend, this generates neural activity
What are outer hair cells?
more of them than inner hair cells, anchored in basilar and tectorial, contract/relax to change tectorial membrane stiffness (changes what inner detect), can get input from brain on what to do
What are inner hair cells?
less than outer hair cells, anchored in basilar and touch tectorial, non-regenartive, auditory receptors,
What is the ventral pathway for hearing?
auditory object recognition
What is the dorsal pathway for hearing?
auditory control of movement
What is the primary vs secondary auditory cortex?
A1 (heschl gyrus, role in analyzing music) vs A2 (planum temporale, forms wernicke area, comprehension)
What is the insula?
cortical region that has a role in language, social cognition, gustation
WHat is tonotopic mapping?
frequencies are coded based on lcoation along basilar membrane
What are the 2 mechanisms for comparing input from both ears?
interaural time difference (differ in soundwave arrival time, computed in medial superior olive)
interaural intensity difference (differ in soundwave loudness, computed in lateral superior olive and trapezoid body)
What is the universal grammar theory?
certain grammatical structures and rules are innate to all human languages, genetically determined capacity for learning language
What is broca’s area vs wernickes?
broca is for speech production, wernicke is for speech comprehension
What is aphasia?
inability to produce or comprehend speech
