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203 Cards in this Set
- Front
- Back
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What is a receptive field?
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region of a receptor surface that causes a sensory nerve cell to respond
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Which cells in the eye fire action potentials?
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ganglion cells in the retina
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how are ganglion cells differentiated?
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Some turn On and some turn Off
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How does someone measure the receptive field of a ganglion cell?
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put small light spots on a screen and see which one causes the photoreceptor to hyperpolarize
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Why do ganglion cells have action potentials?
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they need to send information long distances in the body
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what is adaptation of a photoreceptor?
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when it becomes adjusted to the light levels
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when does pre-synaptic glutamate increase? Decrease?
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Increases when light is off, decreases in presence of light,
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What happens when glutamate is released near kainate and AMPA receptors?
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glutamate binds to an Na+ ion channel and they flow into post-synaptic neuron
---> DEPOLARIZATION |
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What are AMPA and kainate receptors?
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receptors located in the retina with ion channels that bind glutamate and allow Na+ to depolarize the neuron
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What happens to photoreceptors and OFF-bipolar cells in the presence of light? When it is turned off?
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they hyperpolarize, and if the light is turned off, they depolarize
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What are mGluR6 receptors? What happens when Glutamate binds to them?
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receptors involved in ON pathway, when glutamate binds to mGluR6 it activates G-protein which then decreases cGMP levels and cGMP activated Na+ channels close ----> post-synaptic hyperpolarization
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What is the OFF pathway referred to as? Why?
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a "sign-conserving" synapse, since bipolar cells hyperpolarizes just like the photoreceptor
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In the OFF pathway, what happens to OFF bipolar cells?
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they hyperpolarize, just like the photoreceptors
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What is the ON pathway?
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"sign-inverting," the photoreceptor hyperpolarizes in response to light and the bipolar cell does the opposite and depolarizes
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Why is it thought that we have the On and OFF pathways?
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The On pathway is for detecting brighter objects and the OFF pathway is for detecting darker objects
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How and what did Peter Schiller find out about the ON and OFF pathways?
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Blocked sign-inverting synapses in monkeys, they had trouble detecting increases in light but they could detect rapid decreases in illumination
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What and where is the cornea? What is its number 1 function?
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The cornea is the clear film around the eye that allows light to come through
Its #1 function is to refract (bend) light |
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What is the sclera?
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very outer membrane of the eye, it gives the eye its rounded shape
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What is the Fovea?
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part of the very back of the eye that allows for detailed reading
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What is the optic disk?
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Where images leave the eye and go out to the brain
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what is another name for focusing?
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accommodation of the eye
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What type of muscle is the ciliary muscle? What does this mean?
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a sphincter muscle, which means it contracts
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When the ciliary muscle contracts, what happens to the zonule fibers? What happens to the eye? What is this used for?
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the tension in the zonule fibers is decreased, the lens becomes more spherical
when the lens is more spherical you can see things that are more near |
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To Focus on near and far objects, which requires more refraction?
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Near object require more refraction, far objects require less refraction because they come in more of a straight line
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What happens when we focus on far objects in the eye?
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The ciliary muscle increases tension on the zonule fibers, which flattens it and makes it less spherical so that we can straighten out the beam of light and focus on far objects
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what is myopia? What kind of lens is used to correct it?
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short sighted, or near sighted, the cornea is too curved (too spherical, just like when the ciliary muscle decreases tension and it becomes more spherical) so there is too much refraction
Can be corrected by concave lens (because it's flat) |
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What is hyperopia? What kind of lens is used to correct it?
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hyperopia means far sighted, cornea is too flat and not curved enough. Needs convex lens because it is more curved to correct the flatness
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What are cataracts?
What are some risk factors? What is the treatment? |
clouding of the lens
Age UV light exposure Smoking eye injury surgery corrects it by replacing the lens |
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What is glaucoma? If the optic nerve is damaged by glaucoma what happens?
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Glaucoma is when the fluid that cleans the eye goes into the anterior chamber and puts pressure on the posterior chamber, which puts pressure on the eye and eye cells start to die, not regenerating.
The optic nerve cells do not grow back and cannot be fixed |
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What are the risk factors for Glaucoma? Diagnosis? Treatment?
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Risk factors are age, race, family history
diabetes eye injury Diagnosis is done by measuring eye pressure and measuring visual field Treatment for glaucoma is drugs or surgery |
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What is special about the retina?
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it is where light signals are turned into brain signals
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What are the two types of photoreceptors? what do they do in response to light? Where are they located?
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Rods and Cones, they hyperpolarize in response to light
They are located in the very back of the retina |
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What is the "dark current?" What does it result in?
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it refers to that in darkness there is high levels of intracellular cGMP which activate cGMP gated ion channels, which then allow Na+ and Ca2+ ions to get through.
Results in depolarization |
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How do photoreceptors hyperpolarize in response to light?
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light is absorbed by a photopigment which lowers cGMP levels so that cGMP-gated ion channels close and the dark current is off (no Na+ or Ca2+ coming in to depolarize) so this results in hyperpolarization
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What are some characteristics of Rods? Where are they located? what does scotopic mean?
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for scotopic (low light level) vision
more sensitive, but response saturates quickly located on periphery of retina (that's why it's harder to recognize color on the periphery) low spatial resolution |
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How many rods are there per bipolar cell?
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6 rods per bipolar cell
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how many cones are there per bipolar cell?
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one
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What are some characteristics of cones?
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for photopic (high light level) vision
less sensitive (higher threshold) concentrated in the center of the retina more spatial resolution because of less convergence on ganglion cell |
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What are three subtypes of cones?
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short, medium, and long wavelengths for color vision
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What is the lens held by?
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the zonule fibers
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What are the two strange things about the retina?
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photoreceptors are located in the back of the retina
response to light in photoreceptors hyperpolarizes them |
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How do you get color blindness? why do men get it more?
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missing or mutated cone
men get it more because the genes for cones are located on the X chromosome |
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what is protanopia? what is deuteranopia?
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protanopia is L-pigment deficiency
deuteranopia is M-pigment deficiency |
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What are horizontal cells? What happens when glutamate is released by photoreceptors?
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Cells that are linked between photoreceptors in the retina.
When glutamate is released by photoreceptors, horizontal cells are depolarized |
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What do horizontal cells release once they've been depolarized by glutamate released by photoreceptors? What is it and what does it do?
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The release GABA, an inhibitory transmitter that hyperpolarizes photoreceptor terminals
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What are lateral interactions, what do they cause?
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They are when glutamate is released from the photoreceptors or GABA is released from horizontal cells.
lateral interactions cause less hyperpolarization of photoreceptors |
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What are the effects of lateral interaction on On bipolar cells?
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ON pathway bipolar cells are depolarizing, so less depolarization
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What are the differences between P and M ganglion cells?
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P ganglion cells are small, receive input from cones, involved in seeing color
M ganglion cells are involved in motion detection |
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What do lateral interactions do in terms of your vision?
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they enhance differences in what you see
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What are edges?
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differences between light and dark
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Where is the first step of visual processing done?
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striate cortex
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What is the Superior Colliculus?
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Orients the movements of head and eyes, primitive visual system involved in PRIMITIVE REFLEXES
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What is special about the image that is projected on the retina?
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It is inverted
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Where does the projection from nasal retina go? What about the projection from temporal retina?
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Nasal retina projections go to the opposite side of the brain
Temporal Retina projections go to the same side of the brain |
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Where does the temporal retina of each eye see?
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left eye temporal retina sees center-left and right eye temporal retina sees center-right
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What are the nasal hemi-retina in each eye involved in? Where do they pass through?
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peripheral vision, they pass through the optic chiasm
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What is the Lateral Geniculate Nucleus? What kind of receptive fields does it have?
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LGN is the primary processing center for visual information received from the retina, it is found in the thalamus
LGN has Center-surround receptive fields |
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what do ipsilateral and contralateral mean?
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ipsilateral means on the same side as
contralateral means on the opposite side of |
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Wat are the ipsilateral eye layers of the LGN? contralateral?
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layers 2, 3, 5 are ipsilateral
contralateral eye layers are 1, 4, 6 |
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Where are the parvocellular layers located in? What does damage to them cause? What does it not affect?
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The parvocellular layers are located in the Lateral Geniculate Nucleus
Damage to the parvocellular layers impairs visual acuity and color perception, but does not damage motion perception |
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Where are the magnocellular layers located? What does damage to them cause? What does it not affect?
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in the LGN
Damage to the magnocellular layers reduces the ability to see motion, or rapidly changing stimuli damage to the magnocellular layers does not affect visual acuity or color perception |
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what happens if you cut the optic chiasm?
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You lose peripheral vision because the nasal hemi-retina can't send signals
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What did Hubel and Wiesel do and what did they find out?
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experiment to test cat visual stimulation, found that there are simple cells and complex cells which can give a systematic map of orientation tuning and ocular dominance
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How are cells grouped together in the striate cortex?
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they are grouped my orientation and ocular dominance
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What are two general principles of brain organization?
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Individual neurons are tuned to particular features of complex stimuli
Stimulus qualities are represented in an orderly fashion in relevant regions of the nervous system |
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What does damage to the ventral pathway do?
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damage to the ventral pathway results in achromatopsia, which means you can't see color, or prosopagnosia
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What does damage to the dorsal pathway do?
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it results in Akinetopsia, patients cannot see movement
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Where is Area IT and what happens when it is damaged?
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it is in the Ventral pathway, damage induces prosopagnosia
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What does the Where pathway consist of? What does it process?
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dorsal pathway and parietal pathway
the where pathway processes motion, neurons are sensitive to direction of pattern |
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What does the What pathway consist of?
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The what pathway consists of the ventral pathway and the temporal pathway
The What pathway processes detail, object recognition Neurons are sensitive to color and details, such as orientations or faces |
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What is sound?
What is phase? |
Pressure waves of air moleculse
phase is time difference |
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What are the four ways to tell apart waves?
Why does waveform complexity matter? |
phase, length, amplitude, waveform complexity
Most sounds are very complex |
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what is the middle ear made of?
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external oval window and eardrum (tympanic membrane) and ossicles, Malleus, incus, stapes
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What is the outer ear made of and what is its function?
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It is made out of the pinna, the concha, and the external auditory meatus
The Outer ear's function is to collect sound energy and focus it on the tympanic membrane |
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What is the shape of the pinna and the concha? Why?
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funnel shaped, it can collect sounds more easily
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What is the function of the external auditory meatus? What is a bad result of this sometimes?
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the external auditory meatus amplifies 3kHz sound frequencies
uses plosive consonants (ba and pa) which have high energy at this frequency it can also amplify the damage done by loud sounds |
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What are the structures of the middle ear?
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tympanic membrane, stapes, incus, malleus
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What is the middle ear's function?
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to overcome the air-fluid boundary and ensure sound energy crosses that boundary
To amplify sound pressures so that sound can be detected by the cochlea |
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What is the function of the tensor tympani and stapedius muscles? What is this analogous to?
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to contract and stiffen the ossicle to prevent too much sound
this is analogous to pupils closing |
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What are the ossicles? Where are they located?
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Stapes, Incus, Malleus.
Located in middle ear, connecting the tympanic membrane to the oval window |
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What do the ossicles do? (Malleus, incus, stapes)
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move membrane covering the oval window
act like levers to amplify sound pressure with mechanical advantage |
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What are the two ways the middle ear amplifies pressure waves?
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Mechanical advantage ossicles act like levers to amplify sound pressure
the surface area of the tympanic membrane is way bigger than oval window |
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When do the tensor tympani and stapedius muscles contract? What does this result in
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in response to large sounds
This results in decreased sound transmission |
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What does the eustachian tube do? Normally is it open or closed? When does it open?
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regulates pressure in the middle ear
Normally is closed, opens when you yawn or swallow to equalize pressure |
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What is the inner ear composed of? How does it work?
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The Cochlea and the Auditory Nerve
The inner ear works by first having the stapes push/vibrate on the cochlea to move fluids down the basilar membrane |
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What does one region of the basilar membrane resonate with? what is tonotopy?
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one frequency
Tonotopy is the topographical mapping of frequency |
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What does the organ of corti do? What do the inner hair cells do?
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holds the hair cells (sensory neurons)
the inner hair cells turn mechanical energy into neuronal energy |
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Where is the organ of corti? what is it composed of?
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the organ of corti is in the tubes of the cochlea next to the auditory nerve
The organ of corti holds the inner hair cells and outer hair cells, efferent axons are connected to all of these hair cells from the base of the organ of corti and they all come together to make a thick "wire" of axons called the afferent axons, and the basilar membrane is along the base of the organ of corti as well. The hair cells are covered by the tectorial membrane |
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How does the basilar membrane result in sound transmission to the brain?
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The Basilar membrane moves up and down, pushing hair cells, which pushes the tectorial membrane and then the hair cells feel the tectorial membrane moving and they transmit the signal
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what is the structure of the stereocilia and where exactly are they located?
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The structure of the stereocilia is 3 "flagella" on top poking out of the organ of corti, with the other half of it below, embedded in the organ of corti that contains the nucleus, vesicles, and a synapse that is connected to an afferent nerve
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What is the endolymph? Where is it?
Where is the scala media? |
The endolymph is the fluid right above the hair cells that the hair cell flagella (top part) are is contained in, and it is above the organ of corti
The scala media is the region above the hair cells and tectorial membrane right above the organ of corti |
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What is special about the endolymph?
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there are high levels of K+ in that region, with a voltage of 80 mV
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What is the Scala Tympani?
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The Scala tympani is the large region beneath the organ of corti that has a 0 mV voltage
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What are the levels of K+ in the inner hair cells? The Scala Media? The Scala tympani?
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in the inner hair cells the voltage is
-45 mV The Scala Media has a voltage of 80 mV because of high K+ The Scala tympani has a voltage of 0, it has low levels of K+ |
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How does signal transmission happen in the stereocilia? (COMPLETE)
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At rest, the stereocilia tip links have not been disrupted to allow for K+ to flow in from the endolymph.
When the stereocilia are displaced, the tip links are disrupted and K+ flows in from the endolymph to depolarize the hair cell Then, voltage-gated Ca-channels in the lower part of the hair cell open, depolarizing the cell more and that activates vesicles that transmit chemicals across the synapse to the afferent nerve (which is connected to the brain) Then, K+ channels open, which hyperpolarizes the cell body again by allowing K+ to flow out. |
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What are tip links? What happens when they are disrupted?
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They are potassium channel connections on the tips of the stereocilia that, when disrupted, open K+ channels that result in depolarization of the hair cell
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What is does mechanoelectrical transduction by hair cells refer to?
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the stereo cilia tip links opening, allowing K+ to come in and depolarize, Ca2+ channels opening, and then the transmission of chemicals from vesicles across the synapse to the afferent nerve which goes to the brain
THAT WHOLE PROCESS |
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What can cause conductive hearing loss? What is the treatment for it?
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plugging of outer ear, damage to tympanic membrane, stiffening of ossicles
Treatment for conductive hearing loss is an external hearing aid to amplify sound |
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What causes sensorineural hearing loss? What is the treatment? How can you tell whether someone has it?
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hair cell death/damage, damage to inner ear
Treatment of sensorineural hearing loss is cochlear implants that stimulate the VIIIth nerve You can tell whether someone has it using the Weber test |
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What is the Weber test?
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A test for sensorineural hearing loss, you use a tuning fork and stick it on your skull, and if they have sensorineural hearing loss, then it shouldn't be as loud
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What percentage of projections to the brain are from inner hair cells?
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95% are from inner hair cells
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What do the outer hair cells do?
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Outer hair cells amplify the movement of the basilar membrane by expanding or contracting in response to sound. This changes the flexibility of the basilar membrane
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Where are the inner and outer hair cells?
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embedded in the organ of corti, the inner hair cell is farther to the left, nearer to the efferent axons and at the end of the basilar membrane
The outer hair cells are right above the middle of the basilar membrane, there are 3 of them embedded in the organ of corti |
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What is tinnitus? What damage is it evident of?
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Tinnitus is a ringing in the ears, comes from cochlear damage
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What is the evidence for cochlear amplifier (outer hair cells mostly)?
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if you play a short noise then your ear will produce sound
Stimulation of the olivocochlear bundle (input to outer hair cells) broadens tuning curves of auditory nerves sensitivity of auditory nerves is decreased when outer hair cells are inactivated isolated outer hair cells can contract and expand in response to electrical current |
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What are tuning curves used for?
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Tuning curves are used to describe what frequencies neurons are most sensitive to or what neurons encode
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What is the term cochlear amplifier used to denote?
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When the outer hair cells expand/contract to change the flexibility of the basilar membrane (which increases basilar membrane movement)
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What is special about the tuning curves of inner hair cells? (how do they vary?)
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They vary systematically, they have tonotopy where there are certain regions responsible for different frequencies
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what is meant by characteristic frequency?
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the frequency that cells are most sensitive to
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On the basilar membrane, is the Apex responsible for high or low frequencies? The Base?
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The Apex is responsible for low frequencies
The Base is responsible for high Frequencies |
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How can you tell what frequency a sound is at given neurons?
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You look at which neuron is firing and you could tell by tonotopy
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What is "Volley Theory of encoding auditory information?
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Firing of hair cells is "phase-locked" to vibration
sound frequency may be read directly from spike times BASICALLY WITH EVERY DIP IN THE SOUND WAVE you will see a firing |
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up to what frequency can you determine sound frequency from spike times when looking at interaural timing differences?
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3 kHz
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What are characteristics of aural pathways to the brain?
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Tonotopy is maintained
They are Binaural (input from both ears is processed on both sides) Highly parallel |
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What is the pathway straight from the cochlea (short version, not all the way to the brain)?
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output from cochlea goes to bipolar cells (different from retina) and then to the cochlear nuclei
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What are the two circuits used for sound localization? What are each used for?
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1. Lateral Superior Olive and the medial nucleus of the trapezoid body (MNTB) are used for localizing sound using interaural intensity differences
2. the medial superior olive, uses interaural timing differences to localize sound |
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How is sound localized according to timing? (4 characterisics)
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Sound is localized using interaural timing differences
sound will have different arrival times in each ear depending on location of sound projections from anteroventral cochlear nucleus are arranged so that the axonal length varies systematically Medial Superior Olive cells fire strongly when inputs from both ears arrive at the same time, which gives coincidence detection The sound source may be localized by looking at which MSO cells fire |
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What is the organ used for localization of sound through timing?
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Medial superior Olive
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When a speaker is held up to the left ear, what does input from the contralateral ear do? the ipsilateral ear?
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input from ipsilateral ear excites ipsilateral lateral superior olive cells
Input from ipsilateral ear excites cells in the medial nucleus of the trapezoid body, which inhibits contralateral Lateral superior Olive cells, as in, the signal from the left ear DOESN'T go through the MNTB on the right side because of inhibition at the contralateral medial nucleus of the trapezoid body. |
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What are Medial Superior Olive neurons known for (has to do with sound timing localization)?
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Medial Superior Olive neurons are coincidence detectors
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What are the Organs used for sound intensity localization?
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lateral superior olive and the medial nucleus of the trapezoidal body
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What are some characteristics of using interaural intensity differences to localize sound?
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input from the ear excites cells in ipsilateral lateral superior olive
input excites cells in contralateral MNTB, which in turn inibits contralateral Lateral superior olive |
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Sound input from the right will do what to the lateral superior olive and the medial nucleus of the trapezoid body of each side of the brain?
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the right lateral superior Olive will be excited and the left medial nucleus of the trapezoid body will by excited as well, which will inhibit the contralateral (in this case, left) lateral superior olive
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What frequency are interaural intensity differences used for?
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2 kHz and above
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what do owls use for their map of space? Bats?
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inferior colliculus
Bats use the medial geniculate complex for echolocation |
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Where does the auditory cortex receive inputs from that allows for a tonotopic map?
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the medial geniculate complex
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What happens when the frequencies are too high for interaural timing differences to be able to be interpreted by the brain?
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When the frequency is too high, the nerve firings lose their reliability
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What is special about the auditory cortex? (tonotopy)
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One section of the auditory cortex prefers high frequency and the other low frequency
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What happens to cats without an auditory cortex? Humans?
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Cannot discriminate between sounds used for communication
Humans have trouble processing temporal order of sounds (hear things backwards) |
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Where is the Cribriform plate and what does it do?
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It is in between the brain and the olfactory epithelium, it supports the olfactory bulb
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What is different about olfactory receptor cells as opposed to eye or auditory?
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They are directly exposed to air, not protected like the retina
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What do sustentacular cells do?
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They are right next to olfactory receptor cells, help eliminae toxins
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what is different about mature olfactory cells?
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they have cilia, they use them to detect odors
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What does the mucus contain?
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immunoglobulins that help odorants get to olfactory cilia
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What is the part of the olfactory cell that responds to odorants?
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the cilia, they have olfactory receptor cells
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What is the voltage clamp technique? What does negative current mean?
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the voltage clamp technique records currents flowing into or out of the cell.
Negative current means depolarizing cell body, or positive charge is flowing into cell |
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When olfactory receptor cells are stimulated by an odorant, what happens? (generally what ions are flowing in and out, not in depth)
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sodium and calcium are coming into the cell and Chlorine ions are leaving, depolarization
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what happens in odorant transduction?
First 4 steps |
1. odorant binds receptor, activates olfactory-specific G protein
2. olfactory G protein activates adenyl cyclase III 3. Activation of adenyl cyclase III increases cAMP 4. cAMP-gated Na+ and Ca2+ channels open |
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What are the last 4 steps of olfactory transduction? (after cAMP-gated Na+ and Ca2+ channels have opened)
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5. Influx of Na+ and Ca2+ ions
6. activation of Ca2+ gated Cl- channels 7. Efflux of Cl- ions 8. Depolarization |
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What does calcium do in olfactory receptors?
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interacts with CAM and forms Ca2+-CAM complex
it is pumped out via Na+/Ca2+ exchanger |
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What does Ca2+-CAM complex do?
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binds and opens Cl- channels that allow for efflux
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What does the olfactory G protein increase?
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cAMP
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What is special about olfactory receptor neurons and smells? (what concentrations)
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some neurons only respond to high, mid, and low concentrations, they vary significantly
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What are some characteristics about olfactory receptor tuning? (2)
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each olfactory receptor cell expresses one (or a few) olfactory receptors
Chemical specificity/tuning of a receptor is hard to determine |
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What are the glomeruli?
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spherical structures of olfactory receptor cell bulb (on the other side of the axons
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What do olfactory axons contact?
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mitral cells, periglomerular cells and tufted cells
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what do tufted and periglomerular cells do?
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they are thought to sharpen or alter sensitivity/specificity
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What are glomeruli thought to respond to? (how many oderants?)
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a specific odorant for each
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What does the lateral olfactory tract contain?
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mitral cells
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What is the primary target of the olfactory bulb?
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the pyriform cortex
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What is the function of the somatic sensory system?
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to process mechanical stimuli (touch, vibration, pressure)
process pain and temperature |
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What are the receptors of the somatic sensory system?
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mechanoreceptors
nocireceptors thermoreceptors |
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What is the overview of somatic sensory transduction?
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stimulus changes the nerve endings which leads to a change in ionic permeability of cell membrane that results in a receptor or generator potential
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What are mechanoreceptors? How many are there?
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part of the somatic sensory system, they are specialized for tactile information with rapidly adapting afferents
There are four kinds, Meissner corpuscle, Pacinian corpuscle, Merkel cell-neurite complex, Ruffini's corpuscles |
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What are characteristics of Meissner corpuscle?
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40% of mechanosensory innervation of hand
encapsulated rapid adaptation low threshold of activation sensitive to touch, pressure encode low frequency vibrations |
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What are characteristics of Pacinian corpuscle?
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encapsulated (looks like an onion)
rapid adaptation low threshold of activation sensitive to vibration, deep pressure possibly encode vibrations of objects held in hand |
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What are some characteristics of the Merkel cell-neurite complex?
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25% of mechanosensory innervation of hand receptor cells sit in epidermis
action potentials arise in afferent fiber slowly adapting low threshold of activation sensitive to touch, pressure high spatial resolution stimulation is perceived as light pressure encodes points, edges, curvature, texture |
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What are some characteristics of Ruffini's corpuscles?
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Elongated, spindle-shaped capsules
Sensitive to stretching caused by limb movement possibly encode finger and hand position |
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What are proprioceptors?
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The receptors that signal that a body part is self, receptors for self
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What does the golgi tendon organ have? Where are they located?
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encapsulated afferent nerve endings that are located at muscle/tendon junction
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Where are the central pattern generators located?
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spinal cord
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What does the fovea have more of, rods of cones?
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more cones
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What are simple cells in the primary visual cortex responsible for?
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Orientation and position
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What are complex cells in the primary visual cortex responsible for?
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Orientation and direction
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As muscles stretch, what do the muscle spindles do?
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stretch with it, then they fire
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What do muscle spindles encode?
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muscle length
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What do Group 1a afferents do?
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fire through axons when the muscle is ADAPTING and CHANGING, not sustained
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What do Group II afferents do?
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fire or have activity when muscles are in a sustained position, rather than adaptive responses like Group 1a
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What is the bigger one, the extra or intrafusal muscle fibers? What is another name for the intrafusal muscle fibers?
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The extrafusal muscle fibers are the bigger one
Another name for the intrafusal muscle fibers is the muscle spindle |
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What does stimulating the alpha and gamma motor neurons do?
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causes stretching of spindle
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What do the golgi tendon organs do?
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encode muscle tension
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Where are the golgi tendon organs located?
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at the top and bottom of muscles, they are like little capsules between the junction of the muscle
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What are gamma motor neurons usually for? (what kinds of movement?)
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complicated movement/activities
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From where do group Ib afferents carry information from?
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Golgi tendon organs
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What part of the muscles are gamma motor neurons connected to?
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The muscle spindle, or intrafusal muscle fibers
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What muscle is innervated by the alpha motor neurons?
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extrafusal muscle fibers
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Where are the group 1 and 2 afferents located?
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in the muscle spindle
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What are noci receptors?
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free nerve endings in your dermis that are specialized for sensation of pain and temperature
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What do thermo receptors respond to when compared with noci receptors?
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Thermo receptors respond to lower temperature, they are more sensitive
Noci receptor fires at high temperature |
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What are A delta fibers responsible for?
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sharp first pain
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What are C fibers responsible for?
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the second feeling of pain, not the initial, it is much more longer lasting
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What are the pains that are caused by C fibers and A delta fibers?
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The A delta fibers have a sharp pain
The C fibers have a delayed, diffuse, duller, and longer-lasting pain |
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What is referred pain?
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when pain is felt in areas other than part of the body that is being hurt
pain may be felt at a site other than its visceral source |
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What are the areas of the primary somatic sensory cortex?
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3a, 3b, 1, and 2
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What are each of the areas of the primary somatic sensory cortex responsible for?
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3a is responsible for proprioceptive input
3b, 1 are responsible for tactile input 2 is responsible for both size and shape of objects |
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In the primary somatic sensory cortex, what is special about the order of it?
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areas that are close to each other on the body are close on the somatic sensory cortex
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What is the homunculus?
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a representation in terms of size to the areas that are the most represented in the somatic sensory cortex
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What does plasticity in the primary somatosensory cortex mean?
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It just means that areas that are not used can be taken over by other areas, like where if you lost a finger then the brain uses the space that was for that finger for your other fingers to use
unused aspects of the somatic sensory cortex can lead to heightening of other areas |
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What is Hebbian learning?
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When A firing causes B to fire, the connection from A to B will increase
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Why does the saying "cells that fire together wire together" come as not entirely correct when thinking about A and B?
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Just because A causes B to fire does not mean that B causes A to fire
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What is the period when circuits are particularly vulnerable to perturbation?
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the critical period
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What are flexing and extending muscles controlled by?
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the central pattern generator in the spinal cord
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What happens in development If a cat's eye is sewn shut in early development? if the eye is removed early in development? What if the eye is sewn shut later in development?
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sewn early - the other eye gets all of the response
taken out early - same thing, the other eye gets the response sewn late - Eye has already developed past the critical period and so response is still in both eyes |
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What did Constantine-Paton show in her experiment with tadpoles?
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competitive mechanisms refine synaptic activity and neural activity plays an important role
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Why do inputs from the eyes segregate?
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each eye competes to innervate the target
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does suturing one eye shut have more of an effect than suturing both eyes shut? What does this show?
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yes, and it shows a competitive mechanism because the one eye will win out on innervating the neurons that the other eye normally would
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What are some examples of critical periods?
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monocular deprivation of monkeys and cats
song learning in birds language acquisition in humans |
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What is another definition of the critical period?
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a time when external environmental factors are especially influential
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When do humans start to babble? What do deaf kids do at this time?
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7 months,
Deaf kids try to sign |
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What happens to humans who miss their critical period for language?
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they never are able to communicate as well as humans raised with language
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What is special about infants' potential to learn language? When does this ability decline?
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they can discriminate between any speech sound
This declines at 6 months |
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What is the mcGurk effect?
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it is what happens when we have a learned perception of speech
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What is the difference between AMPA and kainate and mGlur6 receptors? which one is on and which is off?
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AMP and kainate, in response to glutamate, have Na+ channels open that result in depolarization
mGluR6 receptors: when Glutamate binds to them they release a G protein that decreases cGMP levels and cGMP activated Na+ channels close resulting in hyperpolarization AMPA and Kainate receptors are OFF pathway mGluR6 is ON pathway |
