Chapter 7 Neuroplasticity

Question 1

what is habituation

Answer 1

decrease in a response to repeated, benign stimulus

Question 2

process of habituation

Answer 2

one neuron will release less NT turning down the signaling of that pathway

Question 3

one of two ways that signaling can be turned down

Answer 3

first way: more presynaptic inhibition

two: less presynaptic facilitation (reduce the number of NT that spills out)

Question 4

what happens if the brain feels better?

Answer 4

that pathway may not be turned on as much

Question 5

habituation is short term or long term

Answer 5

short term

Question 6

post synaptic terminal can take receptors away. this is…

Answer 6

long term

Question 7

tactile defensiveness

Answer 7

turn down NT release, repetitively doing it then a remodeling of post synaptic membrane

Question 8

roller coaster and inner ear

Answer 8

repetitively on a roller coaster, the inner ear loses NT

Question 9

Long Term potentiation (LTP)

Answer 9

make something easier and in this case it’s easier synaptic signaling

Question 10

LTP turns up or turns down the strength of synaptic connection

Answer 10

turns up the strength

this is easier to signal. process we used everyday to commit something to memory

Question 11

LTP converts….

Answer 11

FROM silent synapses

Question 12

LTP goes from a _____ synapse to ______

Answer 12

silent to active

Question 13

what is a silent synapse

Answer 13

a physical synapse but there is no signal

Question 14

what are the type of receptors associated with LTP and what do they bind

Answer 14

AMPA receptors bind glutamate. this will create AP receptors

Question 15

receptors of action are located….

Answer 15

buried in the cell

Question 16

NMDA is responsive to

Answer 16

glutamate

in our brain the NMDA receptors let in calcium to remodel the cell not an AP

Question 17

look over slide 10 and in the book

Answer 17

okay cool

Question 18

process of LTP step one

Answer 18

NMDA receptors are activated and calcium tells NMDA receptors to pop up into membrane

Question 19

process of LTP step two

Answer 19

glutamate is released to put receptors up into the membrane

Question 20

how does the post synaptic membrane break?

Answer 20

breaks into spines which results in spatial summation

depolarizes at each spine. calcium turns on intracellular enzymes that remodel post synaptic membranes and we can get spatial summation

Question 21

Why does the effort of activity go way down?

Answer 21

receptors of action goes way down because we not only have receptors of AP but it takes way less effort

Question 22

what is the importance of astrocytes?

Answer 22

store and release calcium (cell remodeling)

sotre and release glutamate (release of NT)

Question 23

Long term depression (LTD)

Answer 23

turns down strength of signal. LONG TERM

Question 24

LTD converts……

Answer 24

to silent synapses

Question 25

LTD tries to do what

Answer 25

repeatedly try to apply benign stimulus

not as many receptors are needed so pulls them away

Question 26

what is excitotoxicity?

Answer 26

when cells are killed, their guts of glutamate are spilled and the glutamate goes to surrounding cells.

Question 27

What does glutamate done after being spilled?

Answer 27

opens NMDA channels on all surrounding neurons and keep them open. this results in TOO much calcium getting in

Question 28

results of too much calcium

Answer 28

glycolysis–> lactic acid–> lower pH
turns on protease (eats protein): cell disassembles its own membrane ad protein enzymes are turned on inappropriately and produce free radicals as poison
where solute goes, H2O follows=swelling

Question 29

free radicals

Answer 29

stop normal cell processes

Question 30

goals in stroke and head trauma

Answer 30

stroke: restore blood flow

head trauma: reduce swelling

Question 31

what is an axonal injury?

Answer 31

an axon is broken

Question 32

3 ways an axon can be broken

Answer 32

1. axon distal will degenerate
2. myelin will degenerate ( these two are direct)
3. muscle will atrophy (indirect)

Question 33

distal degeneration is also called

Answer 33

Wallerian degeneration

Question 34

what piece can regrow?

Answer 34

proximal piece

Question 35

Axonal injury in periphery, 2 ways the target gets a new nerve supply

Answer 35

1. collateral sprouting: surviving axons can send out extra sprouts to innervate what has lost its innervation
2. regenerative sprouting: surviving proximal axon can regenerate itself (this occurs when the cell body survives, 1 inch a month)

Question 36

ways the synapse changes following injury

Answer 36

recovery of synaptic effectiveness, denervation hypersensitivity, synaptic hypereffectiveness, unmasking of silent synapeses, and functional reorganization of cerebral cortex

Question 37

recovery of synaptic effectiveness

Answer 37

neural inflammation squeezes the axon until it shuts off, no AP due to synaptic transmission
when the edema is controlled, the axon wakes back up and starts functioning again

reduction of swelling in the brain promotes recovery in the brain

Question 38

denervation hypersensitivity

Answer 38

loss of nerve cell produces a hypersensitive presynaptic cell. all are searching for input
receptors may be turned on improperly

Question 39

synaptic hypereffectiveness

Answer 39

each terminal bunch makes connection to this downstream axon
some sort of damage has taken away the two bottom branches, axon survived proximally and distally but number of connections was reduced

body makes connections stronger than they used to be

NO spatial summation but overwhelm it with a ton of NT and try to promote an AP

Question 40

unmasking of silent synapses

Answer 40

many silent synapses in the membrane

our goal is to wake up silent synapses within the context of meaningful function
in the picture blue is NMDA channel, glutamate opens and more go to it

Question 41

functional reorganization of cerebral cortex

Answer 41

synapse that is chosen stops working, wake up other silent synapses to give a route for that message