Chap 25: Plasticity Flashcards
What are the first 5 principles of plasticity ?
- it is common to all nervous systems
- Occurs at many levels
- There are two kinds of plasticity as a result of experience
- Behavioral changes correlate to plastic changes
- Experience-dependent changes interact
What are the last 5 principles of plasticity?
- related to experiences that are relevant to the animal
- it is age dependent
- is it time dependent
- related to the intensity and frequency of experiences
- can be maladaptive
Principle 2: At what levels can plasticity be observed ?
- behavior
- neural imaging
- cortical maps
- physiology
- mitosis
- molecular structure
- synapses
Principle 2: Describe Cortical Maps
maps that provide topographic representations of the external world
- motor training can increase motor maps components
- for example, a pianist has larger cortical representation for musical abilities
Principle 2: Describe the level of synapses and mitosis
synapses
- plasticity changes in the arborization of dendrites
Mitosis
- olfactory bulbs, hippocampus and striatum undergo cell reproduction throughout life
Principle 2: Describe the level of the molecular structure
Study on rats
- rats placed in complex environments activate more than 100 genes in response to the experience
Principle 3: What are the 3 types of plasticity from experience ?
- Experience-expectant
- Experience-Experience-dependant
Principle 4: Describe the correlation between plasticity and behavior
synapse number may increase for one learned behavior, but it can decrease for another
Principle 5: Describe how various experiences interact with plasticity
- complex environments may alter plasticity but it can be inhibited through early exposure to stimulant drugs
- affects the frontal lobes principally
Describe principle 6
- behaviors can be learned more readily (plasticity responds best) to behaviors that are relevant to an animal
- for example, food aversion is easily learned while the quadric formula is not
Describe principle 7, 8 and 9
- plasticity is dependent on age, and time and frequency and intensity of experiences
Describe principle 10
- exposure to drugs can also negatively alter brain plasticity
What is the sequential process of brain injury in stroke ?
- changes in ionic balance
- changes in transmitters: glutamate is released and calcium channels remain open
- Toxic levels of calcium enters the cell
- alteration in protein production
- tissue becomes inflamed threatening cellular integrity
Describe the recovery of the motor cortex
- reflexes return
- rigidity
- grasping
- sequential movement of the shoulder elbow, wrist and then hand (develops outward)
What is the likelihood of recovery from the 4 main aphasias ?
- Conduction: 60-100%
- Broca’s: 20%
- Wernickes: 60%
- Global: <10%
What variables increase the likelihood of recovery as discovered from functional imaging ?
- most likely to recover if you are a young women, left-handed, intelligent and optimistic
Describe the treatment of stroke
- must administer tPA’s within 3 hours of stroke onset, after receiving CT or MRI to confirm the stroke is not hemorrhagic
What is constraint-induced therapy ?
immobilizing the unaffected limb and forcing the injured limb to participate in movement thus facilitating recovery
In deep brain stimulation, stimulation of which brain regions are associated with improvements for which disorders ?
stimulate the:
- sub thalamic nucleus/globus pallidus for parkinsons
- striatum or sub thalamic nucleus for depression
- fornix/hippocampus for Alzheimers