Exam 2: Neuroplasticity

Dr. Ghosh - Spring 2024

what are the 4 types of structural changes that can occur in the brain?

synaptic plasticity
synaptogenesis
neuronal migration
neurogenesis

hat are the 2 types of biochemical changes that can occur in the brain?

nucleic acid synthesis
protein synthesis

what is the premature neural stem cell?

neuroblast

where are neuroblasts continuously regenerated in the adult brain?

ventricular-subventricular zone (V-SVZ)

after neuroblasts regenerate in the V-SVZ they migrate where?

olfactory bulb

where do the neuroblasts mature?

olfactory bulb

after the neuroblasts mature in the olfactory bulb, they are integrated into...

the neuronal circuitry

when a brain injury occurs, what migrates rapidly to the injury site and differentiates into functional neurons?

neuroblasts

what is neurogenesis?

the process by which neurons are generated from neural stem cells

where does neurogenesis continue to occur throughout our lives?

hippocampus, olfactory bulb, and cerebellum

Cells outside the hippocampus, olfactory bulb, and cerebellum can die but cannot be

formed

brain remodel is based on what 3 factors

repetitions
functional movement
environment

If one brain hemisphere is damaged, what can the intact hemisphere sometimes do?

take over some of the functions of the damaged lobe

a first key principle of neuroplasticity is brain activity promotes brain _________________

reorganization

presenting oneself with challenging environments, interacting in social situations, and getting involved in physical activities will boost what?

growth of neuronal connections

rehabilitation therapy attempts to stimulate __________ __________ through specific _________ ___________

particular neurons (that may not have been available for some time)
motor activity

if new connections do not from, there will be further

damage/degeneration

what is the role of rehab movement therapy?

1. strengthen and develop synapses
2. guide axonal sprouting
3. facilitate unmasking of alternative or previously subservient pathways

rehab helps sensory stimulation through movement that uses what 3 kinds of sensation?

proprioception, kinesthetic sensation, tactile sensation

rehab helps support new connections in the brain, where does most of this occur?

hippocampus (memory)

following injury, rehab therapy can prevent what?

secondary cascade

proprioception occurs in the ___________ whereas kinesthetic sensation occurs in the ____________

muscle
tendon

learning and memory involve persistent, long lasting changes in strength of...

synaptic connections

large and diffuse areas of the brain show a lot of synaptic activity during the initial phase of?

motor learning

when a task has been learned...

only a small distinct region of the brain show increased activity

repetition of specific stimulus causes increase in the ____________ and _______________ of new proteins that altar a neurons _______________ and promote new ________________

synthesis and activation
excitability
connections (synapses)

the cellular mechanisms for formation of memory is called

long-term potentiations

what is the function of the hippocampus?

long-term potentiation

what lobe is the hippocampus located in?

temporal lobe

long term potentiation appears to change:

conversion of silent synapses to active synapses

changes of the shape of the postsynaptic membrane

do non-neuronal cells also play a role in brain plasticity?

MAYBE in challenging environments; increased connections between astrocytes and neurons are observed in rats raised in challenging environments

some neurons can regenerate their...

(in PNS NOT CNS)

axon

if the cell body is injured the nerve cell...

will die

what is Wallerian degeneration?

a process that results when a nerve fiber is cut or crushed and the myelin separates away from the segment and the axon swells and breaks into short segments (distal end)

rapid loss of neural transmission on the distal stump

in addition to the axonal degeneration, the cell body undergoes... (if damage to cell body)

chromatolysis (cell death)

sometimes the post-synaptic cell undergo degenerative changes and also

die

What is neuropraxia? does degeneration occur?

injury to nerve that causes transient loss of function

no degeneration-nerve functions reverse

(compressing nerve)

what is axonotmesis?

injury that damages the nerve tissue without severing the nerve. Here Wallerian degeneration occurs distal to injury (crush injury)

What is neurotemesis?

the injury that damages the nerve tissue with total severing of the nerve fibers, this damage is irreversible due to lack of regeneration

what is retrograde degeneration?

degeneration of axon stump proximal to lesion. proceeds from distal to proximal

in retrograde degeneration what changes occur?

chromatolysis of cell body
swelling of cell body and fragmentation of ER

regeneration of damaged axons take place through

sprouting

functional regeneration of axon occurs most frequenctly where? why?

peripheral nervous system because of production of NGF by Schwann cells and recovery process is slow

recovery process rate?

1mm of growth per day

if an axon of the CNS is damaged, there will be no

regeneration

why do the CNS cells not regenerate?

lack of NGF and inhibition by oligodendrocytes

when can sprouting by peripheral axons cause problems?

when an inappropriate target is innervated

after a peripheral nerve injury, motor axons may innervate....
what does this cause?

different muscles than previously

causing an unintended movement called synkinesis

can synkinesis disappear? How?

yes, when an individual relearns muscle control