MIDTERM Flashcards
(99 cards)
1
Q
neuron structure viewing methods
A
silver impregnation cell dye injection extracellular dye tracing antibody labeling transgenic cell labeling 3d imaging
2
Q
silver impregnation
A
structure
subset of cells take up silver
3
Q
cell dye injection
A
structure
inject dye into cell
flourescent or chemical rxn
4
Q
extracelullar dye tracing
A
structure
dye interacts with membrane
fluorescent or chemical
5
Q
antibody labeling
A
structure
antibody for certain proteins
fluorescent or chemical
6
Q
transgenic cell labeling
A
structure
cells genetically programmed to express markers
brainbow and fluorescent
only in model species
7
Q
neuron physiology viewing methods
A
electrphysiology voltage sensitive dye calcium imaging fMRI PET
8
Q
electrophysiology
A
physiology
records cellular activity
direct measurement, no delay
extracellular, intracelullar, patch clamp
9
Q
voltage sensitive dyes
A
physiology
dye reacts to voltage changes and fluoresces
fast, indirect
10
Q
calcium imaging
A
physiology
modify cells to fluoresce with calcium
wide field populations = whole brain
recording RESPONSE - delayed
11
Q
fMRI
A
physiology
blood flow
12
Q
PET
A
physiology
blood flow with labeled marker
13
Q
patch clamp recordings
A
physiology electrophysiology
diff configurations of attaching pipette to whole or part of cell to view channel activities
cell attached = against membrane with suction, no cell disruption
perforated patch
whole cell
outside out = intracellular faces pipette
inside out = extracellular faces pipette
14
Q
graded potential
A
temporary MP changes only up or down in voltage diff responses to diff stimuli slow and short distances passive change
15
Q
action potential
A
actively conducted signal only ganglions continuous propagation fast and long distance triggered at threshold regenerative
16
Q
spike frequency
A
information on action potentials
# spikes/unit time
rate coding = direct relationship between intensity and rate of spikes
sparse coding = indirect relation (inhibitory)
Hz
17
Q
chemical synapse
A
NT released between neurons
NT in presynaptic vesicle
AP releases NT into cleft
NT bind to postsynaptic receptor to induce AP
18
Q
electrical synapse
A
2 cells electrically joined
continuous cytoplasm
gap junctions conduct electric charges both ways
19
Q
postsynaptic potential
A
excitatory/inhibitory response to stimuli
EPSP = excitatory
IPSP = inhibitory
20
Q
electricity
A
ion flow
21
Q
voltage
A
v
difference in electrical charge between two points
mV
22
Q
current
A
I
rate of ions flowing
amperes
23
Q
resistance
A
R
more resistance less current
24
Q
gating
A
facilitated diffusion where a channel opens or closes to allow ions
25
selectivity filter
part of the channel that selects for diff ions
26
driving force
which way ions move, how far the MP is from its eq potential
biggest driving force is highest current
membrane potential - equilibrium potential
27
equilibrium potential
```
Eion
where the ion current is 0
reversal potential
nernst equation - ion concentration in and out
feature of ion
na = 58
K= -90
Cl = -90
Ca = 120
```
28
voltage clamp
hold voltage constant measure current
command voltage and feedback current
applied to patch clamp
29
channel conductance
P or g
ability of channel to pass ions/current
siemens
current/MP
30
resting membrane potential
depends on membrane permeability of each ion
at rest: K+ very permeable and Na+ and Cl- somewhat
GHK equation
more K+ inside, more Na+ outside
31
sodium potassium pump
maintains gradient
3 sodium out 2 potassium in
ATP to promote sodium binding and potassium release
more positive w/o
32
positive feedback loop
Na+
| inward Na+ current --> depolarization --> increase in gNa --> inward Na+
33
negative feedback loop
depolarization --> increase in gK --> outward K+ current --> repolarization
34
ionic basis of AP
1. membrane depolarizes to threshold
2. VG Na+ channels open and become inactive (gNa rapid inc then dec)
3. VG K+ channels open slow, close with hyperpolarization (gK inc then slow dec)
4. VG Na+ channels recover from inactivation
5. return to RMP
35
time constant
t
how fast MP changes
smaller t - faster MP change
36
length constant
λ
how far MP changes spread
for long signal, big length constant
for big constant, inc. resistance and dec. internal resistance
37
membrane capacitance
cm
| how much charge can move through membrane
38
membrane resistance
rm
ability for ions to flow - leakiness
high rm --> high length constant
39
internal resistance
ri
ions present in cytoplasm
small ri --> large length constant
40
delay in gate opening solutions
increase rm --> increase length constant --> increase axon diameter
increase rm --> increase length constant --> add myelin
decrease ri --> increase length constant --> high ion conc.
41
hodgkin huxley experiments
1: ions responsible for current? drugs to block channels (TTX-Na) (TEA-K)
fast VG Na+ for depolarization, slow VG K+ for hyper
2: voltage? change MP and observe current
more depolar opens more VG K+, gNa also inc with depolarization even though less DF
3: VG Na+? pre-pulse + depolarization to measure early current
hyperpolar pre gives bigger Na+ current, depolar gives smaller
40% channels inactive at rest
inactivation mV dependent and separate
more depolar, more Na+ inactive, more hyperpolar, more Na+ active
4: different conduction? drugs to measure currents at diff MP, calculate g
Na+ and K+ similar voltage sensitivity, peak conductance overlap
conclusion: activation of Na+ conductance, inactivation of Na+, delayed rectifier
42
h
0-1 paramater describing % channels active
time constant of channel activation
60% at rest
43
threshold
K+ and Na+ current equal but unstable
equal conductance
above threshold VG gates initiate imbalance
44
absolute refractory period
time following AP
no stimulus can trigger another AP
4 subunits
45
absolute refractory channel activation
S4 charge relocates with depolarization, segment rotates
S6 moves to open channel
K+ channels open 1 ms later
gating current
46
gating current
charge through S4 subunit K+ channel
absolute refractory
depolarize to 56, hyperpolarize -56, 2 waves to get gating current
47
absolute refractory channel inactivation
ball and chain model
depolarization activates amino acid ball to close pore site
reverse for repolarization
48
relative refractory
follows absolute
| threshold very high
49
after hyperpolarizing potentials (AHP)
```
relative refractory
helps regulate frequency of AP
caused by:
delayed rectifier still open, drive MP to eK
calcium
ATP pump
```
50
calcium role relative refractory
```
VG Ca channels open during depolarization
Ca in
Ca activated K+ channels open
fast AHP - delayed rectifier
slow AHP - Ca and K
```
51
electrical synapse
```
physical connection
gap junction made by connexon
behave together time wise
happens in cardiac muscle, epithelial, smooth muscle, gland
fast
```
52
chemical synapse
slow release of NT
common in CNS and PNS
calcium influx triggers NT release
Ca2+ channels concentrated at dendrites to allow more Ca2+ and more NT
53
quantum
chemical synapse
| amount of NT/vesicle
54
chemical synapse receptors
```
ionotropic = NT binds and channel opens
metabotropic = not ion channels, NT binds and channel opens elsewhere (direct and indirect)
```
55
metabotropic receptors
chemical synapse
direct - membrane delimited: direct opening by gpcr, beta gamma goes down membrane to open channel
indirect - alpha subunit goes on adventure and starts signal cascade to open channel
56
neuromuscular junction
where motor neurons innervate muscles
synapse between motor neuron + skeletal muscle
most chemical synapse data from NMJ (easy, can keep alive)
underneath terminals are postjunctional folds lined with receptors
humans - 1 motor fiber 1 neuron
crustaceans - multiple neurons per fiber (graded)
57
end plate potential
```
NMJ
depolarization
acetylcholine mediated
decreases farther from endplate
ACH receptors in postjunction folds (ionophoresis)
```
58
EPSP
glutamate
| 2 ionotropic receptors (AMPA, NMDA)
59
ionotropic receptors
both bind to glutamate
AMPA = fast, Na in K out - responsible at neg mV
NMDA = slow due to Mg2+ block, calcium permeable, cation channel, opens more with high frequency spikes - needs depolarization to remove mg
strengthened by long term potentiation
60
long term potentiation
AP then glutamate release then AMPA open
| with more glutamate, more depolarization, NMDA open, more Ca2+, more AMPA, more cations, smaller glutamate needed
61
IPSP
GABA and glycine
both open Cl- channels
more presynapse depolarization more Cl and hyperpolarization
62
navigation methods
```
genetics - turtles, whales
mental maps
instinct
celestial cues (sun, moon, stars) - butterflies, dung beetles
smell
magnetoreception - birds, turtles
communication
ocean currents
```
63
hippocampus
memory formation and space representation
64
entorhinal cortex
represents spatial info
| neurons in EC send information to hippocampus
65
place cells
```
you are here
hippocampus
3D and 2D
fire when in place assigned in brain
experience based
information from EC cells
```
66
head direction cells
direction of head relative to body in space
EC
specific direction per cell
67
border cell
edges of space
EC
diff cell for each border direction
68
grid cell
map of space
spiking pattern across arena
EC
69
physical space encoding
place, grid, border, head direction cells
grid, border and head direction in EC encode place cells
all receive information from sensory system
70
perforant pathway
navigation pathway
cells from EC provide info to dentate gyrus
granule cells project to CA3
pyramidal/place cells in CA3 can project back to CA3 or CA1
no PP, place cells do not work
71
firing field
area causing neuron to respond
72
grid field
firing locations of grid cells to create array covering 2D surface
from physical exploration
73
place field
firing field for place cell
| 2D or 3D
74
light properties
color (wavelength) - subjective to human experience
polarization
intensity - irradiance or number of photons available, used in dark
contrast - uses color, polarization, and intensity to compare, needed for vision
75
eye types
simple lens - vertebrates, gastropods, lens reflects light onto lots of receptors
compound eyes - insects, crustaceans, lots of lenses reflect to one receptor each
76
rhabdoms
compound receptor cells
good at absorbing polarized light
microtubules with molecules that absorb light
if molecules in same direction, better absorption
humans have planar discs, no preferred angle for polarization
77
landmark navigation
animal uses external cue to determine location
pinecone and wasp test
uses color, contrast, intensity, and position
78
path integration strategy
animal uses self movement to obtain trajectory
need to know distance and direction
desert ants count with normal legs, stilts, stumps
NOT VISION
79
celestial cues
vision cues
| sun and moon make polarization patterns that change throughout the day
80
central complex
encodes directional information
| similar to hippocampus
81
optic lobes
visual centers behind eyes
82
protocerebral bridge
flies
helps control movement
cells responding to polarization
83
ellipsoid body
```
flies
donut
lower central body
directional compass
similar to head direction cells
```
84
fan shaped body
flies
| upper central body
85
sound properties
wavelength/frequency
| amplitude/pressure/volume - wave height
86
hearing pathway
pinnae collect waves
eardrum/tympanic membrane vibrates
fluid and ossicles behind eardrum vibrate
cochlea vibrate by ossicles
vibrations down cochlea to basilar membrane (based on vibration loc)
hair cells on basilar membrane hyper/depolarize based on movement
if depolarize, NT to afferent cells to brain
87
hair cells
produce graded potential to release NT to axons
afferent - hair cell to CNS
efferent - from CNS to hair cell (change sensitivity)
tip links open cation channels (Ca2+)
channels open when hairs move to tallest, depolarization
channels close when hair pushed away from tallest
88
tonotopy
map of tones or frequencies in the brain
primary/secondary auditory cortex
corresponds to diff cochlea parts
higher freq at cochlea base
89
interaural time difference
sound localization by computing timing and intensity from ears
intensity higher in close ear
sound received faster to closer ear
90
sound processing
cochlea -> superior olivary nuclei -> inferior colliculus
lateral superior olive - intensity
medial superior olive - timing
dorsal - monaural tonotopy sent higher (inferior colliculus and auditory cortex)
ventral - binarual responses sent to superior olive
91
multimodal processing
ITD information -> tonotopic space map in auditory cortex or inferior colliculi -> visual input + tonotopic map in optic tectum
92
spike train
repeated AP with larger AHP
calcium accumulation with more AP
more K+ calcium channels, more hyperpolarize
rate of firing decreases
93
neural adaptation
change in neuronal response due to stimulation
sensory adaptation
vision in dark/light
94
neural plasticity
brain ability to change synaptic organization and adapt from experience
trauma response, learning, sports
95
short term adaptation
facilitation - progressive increase in synaptic response (ms)
augmentation - increase in synaptic response (s) (with low ca2+ easier to fire)
depression - decrease in synaptic response (s) (normal ca2+ harder to fire)
post tetanic potentiation - immediate depression followed by augmentation (m)
96
long term adaptation
long term potentiation - high freq stimulation of input cells creates larger EPSP (hours/days) (AMPA increase)
long term depression - LTP inverse, post synapse accumulation of ca2+
97
lateral inhibition
stimulation of 1 receptor inhibits those next
| enhances stimulation
98
geomagnetic field
field of earth
mN = magnetic north gN = geographic north
declination = angle between mN and gN (changes with latitude)
inclination = angle between GMF lines and gravity
intensity = strength of magnetic field
99
magnetoreception theories
light dependent = UV sensitive cryptochrome in eyes - birds and reptiles
magnetite dependent = reaction involving magnetite crystals - insects
