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Nervous and Sensory Systems!
Justin [email protected] Hours: 2-3, Thursdays, Socrates Center
Recitations: Tuesdays 9:10-10:00 N C114, 7:00-7:50 W 116
VocabPineal gland pinea=pine conePons pons=bridgeLingual gyrus lingua=tongueHippocampus sea horseAmygdala almondGeniculate genu =knee e.g. genuflectionFusiform spindle shapedPulvinar pillowPyriform pear shapedVermis worm e.g. vermiform appendixIpsi same (e.g. ipsilateral cortex)Contra opposite, against (e.g. contralateral)
Reading list…Oliver Sacks…
-”Man who mistook his wife for a hat”-”The island of the colorblind”-”Musicophilia”
Eric Kandel-”In Search of Memory”
Division
Division
Sympathetic vs Parasympathetic Division
Sensory information enters brain via ‘’reticular formation’’
Info gets processed in different parts of your brain
Gustatory (Insula)
Smell (olfactory)
Can Mess with them using TMS (trans-cranial-magnetic-stimulation)
Motor and somatosensory cortex
Olfactory cortex (bulb)
Olfactory cortex (bulb)
Visual Cortex
Insula (gustatory cortex – a mysterious place)-also closely linked to addiction
Some MRIs
Some MRIs
Some MRIs
We’re focusing right
here
Taste
Each cell has different mechanism
Each cell has different
mechanism
Note: IP3=inositol triphosphate is another second messenger
Glutamate
Note: ~40 different bitter receptors in humans
Question 107
Certain medications selectively block certain ion channels. Which ion channel blocker would you expect to interfere with your sense of sweet taste?
a) Dihydropyridine – a voltage gated calcium channel blocker used to lower blood pressure
b) Delta-conotoxin – a poison from the cone snail that inhibits deactivation of voltage gated sodium channels
c) Pandinotoxin – a poison from the emperor scorpion, which inhibits the opening of voltage gated potassium channels
d) None of the abovee) All of the above
Question 107
Certain medications selectively block certain ion channels. Which ion channel blocker would you expect to interfere with your sense of sweet taste?
a) Dihydropyridine – a voltage gated calcium channel blocker used to lower blood pressure
b) Delta-conotoxin – a poison from the cone snail that inhibits deactivation of voltage gated sodium channels
c) Pandinotoxin – a poison from the emperor scorpion, which inhibits the opening of voltage gated potassium channels
d) None of the abovee) All of the above
Miracle Berries contain ‘’miraculin’’
-Strongly Binds to sweet receptor binding site at neutral pH-but only activates receptor at low pH
Question 108
What effect will miracle berries have on your taste of different foods?
a) Bitter foods will taste sweetb) Sweet foods will taste sourc) Sour foods will taste sweetd) Sweet foods will taste bittere) None of the above
Question 108
What effect will miracle berries have on your taste of different foods?
a) Bitter foods will taste sweetb) Sweet foods will taste sourc) Sour foods will taste sweetd) Sweet foods will taste bittere) None of the above
-Strongly Binds to sweet receptor binding site at neutral pH-but only activates receptor at low pH
Bitter tastes (~550 known)
cyanidestrychnine
Sweet tastes
Saccharin
steviol
Smell
-~900 receptors in humans-lots of gene duplication events
-Many odors activate multiple receptors-can smell gazillions of stuff
(refer to Dani’s lecture for details)
Smell
-~900 receptors in humans-lots of gene duplication events
-Many odors activate multiple receptors-can smell gazillions of stuff
(refer to Dani’s lecture for details)
Very weird
Smell
-Brain eating amoeba travels through cribriform plate!-first symptoms – altered sense of smell…
Stretch receptors in muscles (propioception)
Oligod
Mechanoreception-lots of different neurons, a few different receptor hypotheses:
Thermosensation
Speaker and Microphone
Solenoid – changing currentÞ changing magnetic field Þ magnet movesÞ Diaphragm movesÞ Air moves
Speaker and Microphone
Solenoid – changing currentÞ changing magnetic field Þ magnet movesÞ Diaphragm movesÞ Air moves
Speaker and Microphone
Solenoid – changing currentÞ changing magnetic field Þ magnet movesÞ Diaphragm movesÞ Air moves
Solenoid – Air moves =>Diaphragm movesÞ Magnet movesÞ Magnetic field changesÞ Current is induced
Hearing
Hearing
Hearing
Stapes pushes against perilymph-transmitting the sound waves
Hearing
Hearing
What about the frequency?
Basilar membrane gets wider towards the center – more floppy (lower resonance frequency)
Implicit Fourier decomposition
Amplification of soft sounds
Outer hair cells inner hair cells
(also contain a special motor protein, “prestin”, which can make them wiggle, amplifying the sound) => otoacoustic emissions
Question 109 Pesticide tributyltin has a very long half-life, and has been used for decades as a pesticide on ocean ship-bottoms, to avoid barnacle and algae growth. Recent studies have shown that tributyltin interferes with prestin function. One might expect this to cause:
a) Global warmingb) High affinity between dogs and tennis ballsc) partial-deafness in marine mammalsd) Corruption in congresse) None of the above
Cochlear implants
Gravity, movement sensation
Don’t forget plants!
Gravity, movement sensation
Don’t forget plants!
In the sacule(verticle)
In the utricle(horizontal)
Rotational Acceleration…
Question 110Sometimes, due to excessive shaking or head trama, otoliths can be rattled out of the utricle or saccule and into the semi-circular canals. What symptom would you imagine this would cause?
a) The ability to hear gravityb) Sensation of falling when you turn your headc) Sensation of spinning when you stand upd) Sensation of falling when you hear a noisee) None of the above
Question 110Sometimes, due to excessive shaking or head trama, otoliths can be rattled out of the utricle or saccule and into the semi-circular canals. What symptom would you imagine this would cause?
a) The ability to hear gravityb) Sensation of falling when you turn your headc) Sensation of spinning when you stand upd) Sensation of falling when you hear a noisee) None of the above
Question 110Sometimes, due to excessive shaking or head trama, otoliths can be rattled out of the utricle or saccule and into the semi-circular canals. What symptom would you imagine this would cause?
a) The ability to hear gravityb) Sensation of falling when you turn your headc) Sensation of spinning when you stand upd) Sensation of falling when you hear a noisee) None of the above
(Benign paroxysmal positional vertigo) - ~1 million doctor visits/year
Question 110Sometimes, due to excessive shaking or head trama, otoliths can be rattled out of the utricle or saccule and into the semi-circular canals. What symptom would you imagine this would cause?
a) The ability to hear gravityb) Sensation of falling when you turn your headc) Sensation of spinning when you stand upd) Sensation of falling when you hear a noisee) None of the above
(Benign paroxysmal positional vertigo) - ~1 million doctor visits/year
Vision
Vision
Cones and Rods, bipolar and ganglion cells
Vision
Vision
fovea
Macula=spot
Optic nerve
Retinal artery
Vision
Very different appearance
Rods are very sensitive-black and white vision
Cones come in red, blue, and green flavors, and sense color
Both Release GLUTAMATE when depolarized
Rods
Vision Both have membrane stacks
Vision Light causes cis-trans isomerizationRhodopsin changes shape
Rods: Black and White (really, purple) Vision
What does phosphodiesterase do?
Cyclic GMP GMP
It cleaves a phospho-diester bond
Question 111Lets say you were staring out the window during the day, when all of a sudden a phosphodiesterase inhibitor was introduced to the rod cells in your eyes?
a) The membrane voltage will go up, and the rods will release more glutamate
b) The membrane voltage will go down, and the rods will release less glutamate
c) The membrane voltage will go down, and the rods will release less acetylcholine
d) The membrane voltage will go up, and the rods will release more acetylcholine
e) None of the above
Question 111Lets say you were staring out the window during the day, when all of a sudden a phosphodiesterase inhibitor was introduced to the rod cells in your eyes?
a) The membrane voltage will go up, and the rods will release more glutamate
b) The membrane voltage will go down, and the rods will release less glutamate
c) The membrane voltage will go down, and the rods will release less acetylcholine
d) The membrane voltage will go up, and the rods will release more acetylcholine
e) None of the above
PDE causes cGMP->GMP-> sodium channels close
-> membrane voltage becomes more negative-> less glutamate is released.
PDE inhibitor - > opposite series of events -> more glutamate is released
Question 111Lets say you were staring out the window during the day, when all of a sudden a phosphodiesterase inhibitor was introduced to the rod cells in your eyes?
a) The membrane voltage will go up, and the rods will release more glutamate
b) The membrane voltage will go down, and the rods will release less glutamate
c) The membrane voltage will go down, and the rods will release less acetylcholine
d) The membrane voltage will go up, and the rods will release more acetylcholine
e) None of the above
Color VisionDifferent cones express different “iodopsins”
Same mechanism as rhodopsin, but differ by a few amino acids to change absorption peaks
Coordination in retina
In darkness, rods and cones (at ~-40mV) are constantly releasing glutamate
-with light, Na+ channels close, cells hyperpolarize, and glutamate stops. -in response, some bipolar cells depolarize, while others hyperpolarize
Question 112Given their two opposite responses to glutamate, we might guess that bipolar cells…
a) Each have both glutamate-binding sodium channels and glutamate binding chlorine channels
b) Come in two types, one with glutamate-gated sodium channels, and one with acetylcholine-gated sodium channels
c) Come in two types, one with glutamate-gated sodium channels, and one with a metabotropic glutamate receptor, which causes the closing of calcium/sodium channels
d) None of the abovee) All of the above
Question 112Given their two opposite responses to glutamate, we might guess that bipolar cells…
a) Each have both glutamate-binding sodium channels and glutamate binding chlorine channels
b) Come in two types, one with glutamate-gated sodium channels, and one with acetylcholine-gated sodium channels
c) Come in two types, one with glutamate-gated sodium channels, and one with a metabotropic glutamate receptor, which causes the closing of calcium/sodium channels
d) None of the abovee) All of the above
Question 112Given their two opposite responses to glutamate, we might guess that bipolar cells…
a) Each have both glutamate-binding sodium channels and glutamate binding chlorine channels
b) Come in two types, one with glutamate-gated sodium channels, and one with acetylcholine-gated sodium channels
c) Come in two types, one with glutamate-gated sodium channels, and one with a metabotropic glutamate receptor, which causes the closing of calcium/sodium channels
d) None of the abovee) All of the above
OFF vs ON bipolar cells
Question 113The phosphodiesterase in rod and cone cells is PDE6. Sildafenil (Viagra) is a well known PDE5 inhibitor, but it has also been shown to partially inhibitor PDE6. A common side effect of Viagra is cyanopsia (blue vision), indicating that sildenafil somehow works differently on some cone cells than others. Given what you know from class, pick the most likely cause:
a) Sildenafil is a better inhibitor of PDE6 in S than it is in M and L cone cells
b) Sildenafil is a better inhibitor of PDE6 in L than it is in S and M cone cells
c) Sildenafil is a worse inhibitor of PDE6 in L than it is in S and M cone cells
d) Sildenafil is a worse inhibitor of PDE6 in S than it is in M and L cone cells
Question 113The phosphodiesterase in rod and cone cells is PDE6. Sildafenil (Viagra) is a well known PDE5 inhibitor, but it has also been shown to partially inhibitor PDE6. A common side effect of Viagra is cyanopsia (blue vision), indicating that sildenafil somehow works differently on some cone cells than others. Given what you know from class, pick the most likely cause:
a) Sildenafil is a better inhibitor of PDE6 in S than it is in M and L cone cells
b) Sildenafil is a better inhibitor of PDE6 in L than it is in S and M cone cells
c) Sildenafil is a worse inhibitor of PDE6 in L than it is in S and M cone cells
d) Sildenafil is a worse inhibitor of PDE6 in S than it is in M and L cone cells
Question 113The phosphodiesterase in rod and cone cells is PDE6. Sildafenil (Viagra) is a well known PDE5 inhibitor, but it has also been shown to partially inhibitor PDE6. A common side effect of Viagra is cyanopsia (blue vision), indicating that sildenafil somehow works differently on some cone cells than others. Given what you know from class, pick the most likely cause:
a) Sildenafil is a better inhibitor of PDE6 in S than it is in M and L cone cells
b) Sildenafil is a better inhibitor of PDE6 in L than it is in S and M cone cells
c) Sildenafil is a worse inhibitor of PDE6 in L than it is in S and M cone cells
d) Sildenafil is a worse inhibitor of PDE6 in S than it is in M and L cone cells
normally phosphodiesterase deactivates cGMP-GMP->closes Na+ channels ->hyperpolarizes cone cells ->stops glutamate from going to Bipolar cells
->causes sensation of “seeing something”
Question 113The phosphodiesterase in rod and cone cells is PDE6. Sildafenil (Viagra) is a well known PDE5 inhibitor, but it has also been shown to partially inhibitor PDE6. A common side effect of Viagra is cyanopsia (blue vision), indicating that sildenafil somehow works differently on some cone cells than others. Given what you know from class, pick the most likely cause:
a) Sildenafil is a better inhibitor of PDE6 in S than it is in M and L cone cells
b) Sildenafil is a better inhibitor of PDE6 in L than it is in S and M cone cells
c) Sildenafil is a worse inhibitor of PDE6 in L than it is in S and M cone cells
d) Sildenafil is a worse inhibitor of PDE6 in S than it is in M and L cone cells
normally phosphodiesterase deactivates cGMP-GMP->closes Na+ channels ->hyperpolarizes cone cells ->stops glutamate from going to Bipolar cells
->causes sensation of “seeing something”Inhibiting PDE6 in an S cell causes you to not see blue
-> must work better in M and L cells
Question 113The phosphodiesterase in rod and cone cells is PDE6. Sildafenil (Viagra) is a well known PDE5 inhibitor, but it has also been shown to partially inhibitor PDE6. A common side effect of Viagra is cyanopsia (blue vision), indicating that sildenafil somehow works differently on some cone cells than others. Given what you know from class, pick the most likely cause:
a) Sildenafil is a better inhibitor of PDE6 in S than it is in M and L cone cells
b) Sildenafil is a better inhibitor of PDE6 in L than it is in S and M cone cells
c) Sildenafil is a worse inhibitor of PDE6 in L than it is in S and M cone cells
d) Sildenafil is a worse inhibitor of PDE6 in S than it is in M and L cone cells
Question 114Blood is supplied to the rods, cones, bipolar cells, and ganglion via the retinal artery, which branches out into little arterioles, shown on the right. High intraocular pressure can collapse these arterioles, leading to the slow hypoxic death of ganglion cells (this is called ‘’glaucoma’’)This process begins farthest from the optic nerve, and slowly progresses inward. What would you expect to be symptoms of glaucoma?
a) Progressive loss of color vision around the focal pointb) Progressive loss of peripheral vision (both color and black/white)c) Progressive loss of color peripheral visiond) Progressive loss of black and white vision around the focal pointe) Progressive loss of all vision at the focal point
Question 114Blood is supplied to the rods, cones, bipolar cells, and ganglion via the retinal artery, which branches out into little arterioles, shown on the right. High intraocular pressure can collapse these arterioles, leading to the slow hypoxic death of ganglion cells (this is called ‘’glaucoma’’)This process begins farthest from the optic nerve, and slowly progresses inward. What would you expect to be symptoms of glaucoma?
a) Progressive loss of color vision around the focal pointb) Progressive loss of peripheral vision (both color and black/white)c) Progressive loss of color peripheral visiond) Progressive loss of black and white vision around the focal pointe) Progressive loss of all vision at the focal point
Question:
Question:
Various colorblindnesses
Question 115The gene for S-cone opsin (blue) is on chromosome 7, while the genes for L-cone (red) and M-cone (green) opsin are on the X chromosome. Colorblindness caused by problems with opsin is a recessive trait.Let’s say a man who can’t see green has children with a woman with normal vision. Their first is a son, who can’t see red. What’s the likelyhood that their second son can see red?
a) 0%b) 25%c) 50%d) 75%e) 100%
Question 115The gene for S-cone opsin (blue) is on chromosome 7, while the genes for L-cone (red) and M-cone (green) opsin are on the X chromosome. Colorblindness caused by problems with opsin is a recessive trait.Let’s say a man who can’t see green has children with a woman with normal vision. Their first is a son, who can’t see red. What’s the likelyhood that their second son can see red?
a) 0%b) 25%c) 50%d) 75%e) 100%
Dad: XR YMom: XR XRXR XRY
Xr XrXR XrY
What if we had more iodopsins?
Birds have 4(can see in UV)“tetra-chromats”
What if we had more iodopsins?
Birds have 4(can see in UV)“tetra-chromats”
So do some women! (red and green opsin genes are on X chromosome) – can be mosaic for different iodopsins
What if we had more iodopsins?
Birds have 4(can see in UV)“tetra-chromats”
Mantis-shrimp have 20!
So do some women! (red and green opsin genes are on X chromosome) – can be mosaic for different iodopsins
Melanopsin! (just for fun)
Found in ‘’intrinsically photosensitive retinal ganglion cells” (ipRGCs)
Absorb blue/violet light, ~460nm
Modulate circadian rhythmand pupil dilation reflex
Cis retinal is “dichroic”
Cis retinal is “dichroic”
Cis retinal is “dichroic”
Squid and octopus can see polarization of light
Squid and octopus can see polarization of light
Squid and octopus can see polarization of light
Squid and octopus can see polarization of light
Channel Rhodopsinfound in algae
How about fluorescent sensing?Fuse two genes – Green Fluorescent protein and Calmodulin
-Genetically engineer to be expressed in some neurons, but not others
-when calcium is present, it binds to calmodulin, which changes shape, thus changing the shape of the GFP, thus changing the color of GFP
-can visualize synaptic activity
Sea turtles can sense electromagnetic fields
No one really understands how – best guess is that they use light to homolytically break a bond (probably in a cryptochrome) to form a radical pair-which then does some weird quantum mechanical thing
Sea turtles can sense electromagnetic fields
No one really understands how – best guess is that they use light to homolytically break a bond (probably in a cryptochrome) to form a radical pair-which then does some weird quantum mechanical thing
Explain this!
