Exam 3 Flashcards
(58 cards)
1
Q
hearing
A
- we hear the change in pressure in air that surrounds us
- helps us locate objects in space
2
Q
amplitude
A
- how loud, measured in decibels (dB)
- the height of the wave
3
Q
frequency
A
- the pitch
- wave cycles per second
- more cycles means higher frequency
4
Q
outer ear
A
functions to funnel sound into middle ear
5
Q
middle ear
A
- concentrates energy/sound from a large area to a small surface area
- sound is amplified when ear drum sends info to malleus –> incus –> stapes
- stapes sends mechanical energy to oval window
- concentration of energy from ear drum to oval window goes from a high surface area to low surface area (sounds amplification)
6
Q
tensor tympani and stapedius muscles
A
function to dampen the vibration of ossicles in order to prevent damage to ear
7
Q
inner ear
A
made up of cochlea
8
Q
organ of corti
A
- has 2 sets of sensory cells:
- inner hair cells
- outer hair cells
9
Q
stereocilia
A
protrudes from each hair cell
10
Q
tip links
A
thin fibers that run across each hair cell’s stereocilia
11
Q
auditory info sent to brain
A
- vibration makes stereocilia sway, causing K and Ca ion channels to open
- high concentration of K+ outside cell and low concentration inside cell
- K+ enters cell when sound waves come into ear
- K+ depolarizes hair cell, causing voltage gated Ca2+ channels to open at base of cell
- Ca2+ entry causes release of glutamate or acetylcholine to ganglion neurons
- glutamate or acetylcholine activate ganglion neurons to send sound signals to brain
12
Q
hair cell depolarization
A
hair cells are depolarized by K+
13
Q
basilar membrane
A
- sound vibrations cause basilar membrane to oscillate
- different parts respond to different frequencies:
- high frequency –> displaces narrow base of basilar membrane
- low frequency –> displaces wider apex
14
Q
inner hair cell releases…
A
glutamate
15
Q
outer hair cell releases…
A
ACh
16
Q
function of inner hair cells
A
send auditory information to brain
17
Q
function of outer hair cells
A
amplify sound
18
Q
cortical tonotopy of auditory cortex
A
- higher frequency in posterior auditory cortex
- lower frequency in anterior auditory cortex
19
Q
encoding frequency properties of a sound
A
- place coding or tonotopic representation
- temporal pattern of firing of cells:
- higher firing rates for higher frequency
20
Q
encoding loudness of a sound
A
movement of basilar membrane
21
Q
sound location detection
A
- binaural cues signal sound location:
- intensity differences: different in loudness at the 2 ears
- latency differences between the 2 ears in the “time of arrival” of sounds
22
Q
auditory pathways of human brain
A
cochlear nucleus –> switches side of brain –> superior ovilary nucleus –> inferior colliculus –> medial geniculate nucleus –> auditory cortex
23
Q
retina
A
- images a mirrored upside down on retina
- contains 3 primary layers: ganglion cell layer, bipolar cell layer, photoreceptor cell layer
- contains rods and cones
24
Q
activation profile of visual system
A
- light bounces off image end enters eye
- light hits retina at back of eye
- visual info from retina travels down optic tract
- optic tract sends visual info to lateral geniculate nucleus (LGN) of the thalamus
- thalamus separates visual info and sends it to primary visual cortex (V1)
- V1 further breaks down components of image
- V1 is where visual perception occurs
- V1 sends info to dorsal and ventral pathways
25
the colors we see...
are wavelengths bouncing off that object
26
fovea
- where vision is sharpest and where one focuses on objects
| - highest density of cones
27
process of light entering eye
- cornea and lens focus light entering eye onto retina
- refraction is done by cornea and lens
- bending of light focuses image onto retina
- ciliary muscles in eye adjust focus by changing shape of lens
- light hitting retina activates photoreceptors
- vision is sharpest at fovea
28
refraction
bending of light
29
optic disc
where blood vessels enter and leave eye
30
blind spot
due to lack of photoreceptors in optic disc
31
information transfer of the retina
- photoreceptors (rods and cones) respond to light
- photoreceptors do not fire action potentials, but send a signal (glutamate) to activate the bipolar cells
- the bipolar cells don't fire action potentials but release glutamate to activate the ganglion cells
- ganglion cells are the first sight where action potentials occur
- the axons of the ganglion cells form the optic tract
32
bipolar cells
receive input from photoreceptors and synapse on ganglion cells, whose axons form the optic nerve
33
horizontal cells
are in the retina and contact photoreceptors and bipolar cells
34
amacrine cells
contact bipolar and ganglion cells
35
rhodopsin
- opsin + retinal = rhodopsin
- it is a GPCR
- when light activates retinal to change shape, the g protein (transducin) activates phosphodiesterase (PDE)
- PDE turns cGMP into GMP
- cGMP activates voltage gated Na+ channels
- light hyperpolarizes the rods
- in the dark rods are depolarized
36
3 types of cones
there are cones that respond to either blue, green, or red light and are called S, M, L (for short, medium, and long wavelength light)
37
optic tract
- groups left visual fields into the right visual cortex
| - groups right visual fields into the left visual cortex
38
optic chiasm
- ganglion cell axons form the optic nerve and cross at the optic chiasm
- after passing the optic chiasm, the axons are called the optic tract
- most axons synapse on cells in the lateral geniculate nucleus (LGN) of the thalamus
39
LGN
- information is sent to LGN from optic tract
- LGN is the first structure in the brain where visual information is processed
- LGN contains layers that separate visual movement
40
where pathway
dorsal
V1 --> V2 --> area MT --> posterior parietal lobe
vision for movement, location
41
what pathway
ventral
V1 --> V2 --> V4 --> inferior temporal cortex
vision for recognition (objects, faces)
42
where and what pathways come together in...
- hippocampus
- why memories are highly visual (visual dreams)
- both pathways are important for autobiographical learning and memory
43
cochlear duct
contains tectorial membrane, organ of corti, and basilar membrane
44
primary regions of CNS that control movement
- ACh: initiates muscle contraction
- muscles: moves your skeleton
- spinal cord: sends and receives commands and the reflex
- basal ganglia: motor learning
- motor cortices: motor command
45
motor system
- brain can initiate movement and receives information about movement
- simplest form of movement is the reflex (does not require a brain)
- complex movements are obvious
- many pathologies affect motor system (parkinson's and huntington's)
46
human motor cortical areas
- premotor cortex
- supplementary motor area
- primary motor cortex
47
primary motor cortex
- primary motor cortex maps the body
| - homunculus
48
homunculus
represents the area of the motor strip relating to its body part
49
movements are controlled at several nervous system levels
- in a reaching task, muscle cells change firing rate according to the direction of the movement
- each cell has one direction that elicits highest activity
- an average of the activity can predict the direction of the reach
50
premotor cortex selects motor commands
- encodes the intention to perform a particular movement; thus, they are involved in the selection of movements based on external events
- your brain will have already initiated movement before you are aware of the movement you will make
- you perceive that the choice was yours, but the choice occurred prior to perception
51
motor cortices receive and send...
axons/information to the basal ganglia
example of riding a bike:
- basal ganglia receives commands from motor cortex
- basal ganglia permits motor commands to initiate
- cortex may not know exactly what commands to send (but has general idea)
- commands are not accurate before learning
- during motor learning/procedural learning basal ganglia "fine tunes" motor commands
52
basal ganglia
motor learning AKA procedural learning
53
basal ganglia circuitry
substantia nigra and ventral tegmental area regulate dopamine production
54
additional functions of the basal ganglia
- habitual learning
- drug addiction
- procedural learning
- parkinson's disease
- huntington's disease
- eye movement
- motor planning
55
spinal cord components
cervical
thoracic
lumbar
sacral
56
spinal input and output
- dorsal root: carries sensory information from the body to the spinal cord
- ventral root: carries motor information from the spinal cord to the muscles
57
spine synapse to...
muscles at neuromuscular junction
58
ACh initiates muscle contraction
- motoneurons are nerve cells in the spinal cord that send their axons in innervate muscles
- action potentials travel down the motoneuron, which branches into many terminals near its target
- neurotransmitter ACh is released --> causes Ca2+ to be released --> causes myosin heads to move towards actin --> muscle contraction
