powerpoint 4.3 plasticity after brain damage

Question 0

(plasticity after brain damage-recovery)

most survivors of brain damage show some degree of behavioral recovery

some of the mechanisms of recovery include those similar to the mechanisms of brain development such as the new branching of a…. and d……..

Answer 0

axons and dendrites

Question 1

(plasticity after brain damage)

almost all survivors of brain damage show behavioral recovery to some degree

some recovery relies on the g….. of new branches of a…. and d……..

understanding the processes of recovery will give us new and improved t…….

Answer 1

growth of new axons and dendrites

therapies

Question 2

(brain damage and short-term recovery)

possible causes of brain damage:

• t…..
• i………
• exposure to t…. s…….. or r……..
• degenerative d…….
• closed h… i…….

Answer 2

tumors

infections

exposure to toxic substances or radiation

degenerative diseases

closed head injuries

Question 3

(damage to the brain and short-term recovery continued)

a closed head injury refers to…?

• one of the main causes of brain injury in..?
• after a severe injury recovery can be s… and i………

a stroke or cerebrovascular accident is temporary loss of b…. f… to the brain
-common cause of brain damage in..?

Answer 3

a sharp blow to the head that does not puncture the brain

• one of the main causes of brain injury in young adults
• slow and incomplete

temporary loss of blood flow to the brain
-common in elderly

Question 4

(types of strokes)

ischemia: the most common type of stroke, resulting from a b…. c… or obstruction of an a…..
- neurons lose their o….. and g…… supply

hemorrhage: a less frequent type of stroke; resulting from a ruptures a…..
- neurons are flooded with excess blood, c……, o….., and other chemicals

Answer 4

resulting from a blood clot or obstruction of an artery
-neurons lose their oxygen and glucose supply

from a ruptured artery
-neurons are flooded with excess blood, calcium, oxygen, and other chemicals

Question 5

(effects of strokes)

ischemia and hemorrhage also cause:

• edema: the accumulation of f…. in the b…. resulting in increased pressure on the brain and increasing the probability of further s……
• disruption of the s…..-p…….. pump leading to the accumulation of p…….. ions inside the n……

Answer 5

accumulation of fluid in the brain resulting in increased pressure on the brain and increasing the probability of further strokes

-disruption of the sodium-potassium pump leading to the accumulation of potassium ions inside the neurons

Question 6

(effects of strokes continued)

edema and excess potassium triggers the release of the excitatory neurotransmitter g……..

the over stimulation of neurons leads to s….. and other ions entering the neuron in excessive amounts

excess positive ions in the neuron block m……… in the mitochondria and kill the n…..

Answer 6

glutamate

sodium

metabolism

neuron

Question 7

(immediate treatments for stroke)

a drug called tissue plasminogen activator (tPA) breaks up b… c…. and can reduce the effects of an ischemic strokes

research has begun to attempt to save n…… from death by blocking:

• glu…… synapses
• cal…. entry

Answer 7

blood clots

neurons

• glutamate synapses
• calcium entry

Question 8

(immediate treatments of stroke continued)

one of the most effective laboratory methods used to minimize damage caused by strokes is to…?

c…… protects the brain after ischemia by reducing o………….., a…….., and i………..

Answer 8

cool the brain

cooling

reducing overstimulation, apoptosis, and inflammation

Question 9

(immediate treatments of stroke continued)

cannabanoids have also been shown to potentially minimize c… l… after a brain stroke

benefits are most likely due to cannabinoids anti-inflammatory effects
-research shows that they are most effective in laboratory animals when taken b….. the stroke

Answer 9

cell loss

before

Question 10

(later mechanisms of recovery from brain damage)

following brain damage, surviving brain areas i……. or r……… their activity
-diaschisis: d…….. activity of surviving n…… after damage to other n……

drugs (stimulants) may s…….. activity in healthy regions of the brain after a stroke

Answer 10

increase or reorganize

decreased, neurons

stimulate

Question 11

(later mechanisms of recovery continued)

destroyed cell bodies can/cant be replaced?
but damaged axons do/dont grow back under certain circumstances

-if an axon in the peripheral nervous system is crushed, it follows its m…. s….. back to the target and grows back toward the periphery at a rate of about ? mm per day

Answer 11

cant, do

myelin sheath, 1mm per day

Question 12

(regrowth of axons)

damaged axons do not readily regenerate in a mammalian b…. or s….. c…

• s… t…. makes a mechanical barrier to axon growth
• neurons on the two sides of the cut pull apart
• glial cells that react to CNS damage release chemicals that inhibit a… g…..

research on building protein bridges may help

Answer 12

brain or spinal cord

scar tissue

axon growth

Question 13

(axon sprouting)

collateral sprouts are new b……. formed by other non-damaged axons that attach to vacant receptors

cells that have lost their source of innervation release neurotrophins that induce a…. to form c……… s……

over several months, the sprouts fill in most vacated synapses and can be use…, neu…., or har….

Answer 13

branches

axons, collateral sprouts

useful, neutral, or harmful

Question 14

(denervation supersensitivity)

postsynaptic cells derived of synaptic inputs develop increased sensitivity to the neurotransmitter to compensate for d…….. input

denervation super-sensitivity: the heightened sensitivity to a neurotransmitter after the des…… of an incoming a…

-can cause consequences such as chronic pain

Answer 14

decreased

destruction of an incoming axon

Question 15

(reorganized sensory representations and the phantom limb)

phantom limb: the continuation of sensation of an…?

• the cortex reorganizes itself after the a……… of a b… p… by becoming responsive to other parts of the body
• original axons degenerate leaving vacant syn….. into which other axons sprout

Answer 15

amputated body part

amputation of a body part

synapses

Question 16

(reorganized sensory representations and the phantom limb continued)

the phantom limb can lead to the feeling of sens…… in the amputated part of the body when other parts of the body are stim……

• e.g., a touch on the face can bring about the experience of a phantom arm
• use of an artificial limb can reduce the likelihood of experiencing phantom limb

Answer 16

sensations, stimulated

Question 17

(learned adjustments in behavior)

deafferentated limb: limbs that have lost their aff….. sen…. input

-can still be used but are often not because use of other mechanisms to carry out the behavior are eas…

• has led to the development of therapy techniques to improve functioning of brain damaged people
• -focuses on what they are cap…. of doing

Answer 17

afferent sensory input

easier

capable of doing