Transcript Brain plasticity power point

Brain Plasticity: Improving
Outcomes in Children
Judith Gooch, MD
Beverly Krensky, FNP
Utah Neuro Rehabililtation
Objectives
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Discuss the concept of brain plasticity
Show how plasticity depends upon activity
Discuss the mechanisms for brain plasticity
List techniques to improve outcomes using
brain plasticity
Outline
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Brain plasticity definition
Study of plasticity
Examples of plasticity
Aging and plasticity
Brain injury and plasticity
Mechanisms of plasticity
Techniques to improve outcomes
Practical ideas
Brain Plasticity
• The brain's ability to reorganize by changing
neural pathways and synapses.
• A result of changes in behavior and
environment as well as changes resulting
from injury.
• Allows the brain to compensate for injury and
disease and to adjust in response to new
situations or to changes in environment.
Brain Plasticity
• A property of the nervous system retained
throughout life
• The mechanism for learning, growth and
development
• The result of each motor act and sensory
input
Why should we care about brain
plasticity?
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Promote learning in children
Improve function after brain injury
Overcome difficult childhood experiences
Learn new sports
Prevent cognitive decline as we age
How do we Study Plasticity?
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• Animals: electrical stimulation and
microscopic assessment
• Humans: functional MRI and PET scans assess
changes in brain metabolism with specific
tasks
Evolution of Understanding:
Brain Function
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Localization of function
Questioning of localization
Possibility of brain plasticity
Understanding of brain plasticity
Brain Localization
• Paul Broca, 1861 had a patient who had lost
language skills due to a stroke
• Dissection showed damage to a specific area
in the left frontal lobe.
• Carl Wernicke showed damage in the left
temporal lobe lead to inability to understand
language
Questioning Localization
• Jules Cotard (1868) studied children with early
massive brain disease with loss of left
hemisphere.
• The children could still speak.
Questioning Localization:
Paul Bach-y-Rita, MD
• Introduced sensory substitution for patients with
neurological disorders.
• Accelerometers on patients with vestibular injuries
linked to a computer. Information fed to a small
plate on the tongue. Stimulates different areas of
the tongue, depending on the orientation of the
accelerometers.[ Significantly improves balance.
Examples of Brain Plasticity
Increased Cortical Representation of the Fingers of the
Left Hand in String Players
• Reports
• Brain representation of left hand fingers of string
players larger than in controls
• No differences for right hand
• Amount of brain representation correlated with
the age at which the person started playing
• The representation of different parts of the body
in the sensory part of the brain depends on use
and changes as a result of the needs and
experiences of the person
Neuroplasticity in Braille Readers:
Alvaro Pascual-Leone, MD, PhD
• Blocked the visual cortex of Braille readers using
magnetic stimulation
• Subjects could not read Braille or feel with Braille
reading finger
• Visual cortex was used for information on touch
Navigation-related structural change in the
hippocampi of taxi drivers
• Brain MRI’s of London taxi drivers compared with controls
• The hippocampi of taxi drivers significantly larger than those
of controls
• Hippocampal size correlated with the amount of time spent as
a taxi driver
• The hippocampus stores spatial information and can expand
in people who depend upon navigational skills.
Constraint-Induced Therapy in Stroke:
Edward Taub, MD
• CI therapy group: intensive training for 6 hours
per day for 2 weeks, restraint of the less affected
extremity for 90% of waking hours
• Placebo group: program of physical fitness,
cognitive, and relaxation exercises
• After CI therapy, patients had improvements in
functional use of affected arm.
• Changes persisted for 2 years.
• Placebo subjects showed no significant changes.
Anatomical Plasticity Evidence:
Mark Rosenzweig, PhD
• Changes in brain anatomy and chemistry have
been shown in young and non-injured rats by
changing the environment. Rats raised under
"enriched" conditions had greater cortical
weight, total acetylcholinesterase activity and
cortical depth than their "impoverished
environment" littermates. Scores on a maze
test were also better.
Plasticity is a result of activity and
environmental stimulation
Plasticity: Use it or Lose it
Michael Merzenich, PhD
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Mapped a monkey’s hand map in the brain
Amputated the middle finger
Remapped the brain months later
Brain map for amputated finger disappeared
Maps for adjacent fingers took over space of
middle finger
Aging and Brain Plasticity
Neuroplasticity in old age: induction of hippocampal
neurogenesis by long-term environmental enrichment
• Formation of new cells in the hippocampus declines with age.
• New cell formation in mice living in an enriched environment
five times greater than in controls.
• Improvements of learning, exploratory behavior, and
locomotion.
• Enriched living mice had molecular evidence of less agedependent degeneration.
Video game training enhances cognitive control
in older adults
• Multitasking declines with age.
• By playing a race car videogame, 60 to 85 year
olds improved multitasking compared to a
control group.
• Attained levels beyond those achieved by
untrained 20-year-olds.
• Enhanced sustained attention and working
memory.
• Findings show robust plasticity of the cognitive
control system in the aging brain.
The Dark Side of Plasticity:
(The Brain that Changes Itself
Norman Doidge, MD)
• Plasticity paradox
• Neuroplastic processes which allow us to
change our brains and be flexible can also
promote rigidity
• Repeated times down a hill on a sled creates a
pathway
Brain Plasticity and Culture
(Bruce Wexler)
• Plasticity declines with age
• Becomes more difficult to change in response to the
world
• Familiar types of stimulation are pleasurable
• Seek out like-minded people
• Individuals attempt to make the environment
conform to the internal structures of the brain
• Cultural groups try to impose their views on other
cultures
Brain Injury and Plasticity
• Brain injury itself leads to plastic changes
• Activity and environmental stimulation impact
these changes
Recovery after Brain Injury
• With recovery, there is increased activation of
uninjured cerebellum, motor cortex, and
sensory cortex on both sides.
• Human and animal studies show that postinjury experience has major impact on
changes in the undamaged tissue.
Recovery after Brain Injury
Functional improvement after injury is a
relearning process
Patients must work to re-acquire the ability to
produce behaviors lost after injury
Compensation vs. Recovery
• Compensation with different behaviors after
injury
• Compensation may limit recovery of
impairment
Mechanisms of Brain Plasticity
Mechanisms of Brain Plasticity
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Dendritic branching
Young cells are stimulated after injury
Axonal sprouting
Gene regulation
Decrease of inhibition
Mechanisms of Brain Plasticity:
Activity and Inhibitors
• Adult CNS has an inhibitory milieu to axonal
sprouting
• Activity allows neurons to become insensitive
to growth inhibitors
• Activity increases growth promoting
molecules
License to run: exercise impacts functional plasticity in
the intact and injured central nervous system by using
neurotrophins
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Exercise impacts molecular systems that effect brain plasticity.
Exercise increases brain-derived neurotrophic factor (BDNF).
BDNF increases synaptic function and neuron excitability.
Exercise can promote neuron repair and enhance learning and
memory
Mechanisms of Brain Plasticity:
Improving efficiency
• Monkeys touched with finger tip a spinning
disc with a specific pressure for a specific time
• Brain map for finger tip enlarged as they
learned task
• As they improved, fewer neurons needed
Mechanisms of Brain Plasticity: Normal
development and learning
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• Early over-production of synaptic connections
• Followed by a substantial decrease in the number of
synapses over time
• Information is stored by selecting useful connections
and pruning back surplus connections.
• Learning new tasks can add new neural connections
Plasticity and Learning: Eric Kandel
(Nobel Prize winning learning theorist)
• Short-term memory is linked to functional
changes in existing synapses
• Long-term memory is associated with a
change in the number of synaptic
connections.
Using Brain Plasticity to Improve
Outcomes
• For our patients
• For ourselves
• Focus on motor function in children with
disabilities
• Principles apply to cognitive and emotional
function
Activity to Promote Brain Plasticity
• PLASTICITY DEPENDS UPON ACTIVITY
• Motor learning theory provides a framework
for optimizing learning through activity taking
advantage of plasticity
Motor Learning Theory
The most effective way to learn a task is to
practice on a daily basis in the home and
community setting.
Motor Learning: Practice
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PRACTICE A LOT
Practice variable tasks
Take rest periods
Solve problems through trial and error, don’t
just repeat simple tasks over and over
Other Motor Learning Strategies
• Provide feedback
• Motivate with functional goals
• Promote attention
Attention is Necessary for Plasticity
• Lasting changes in brain maps occurred only
when monkeys paid close attention to the task
• When tasks were performed automatically,
changes in brain maps did not last
Attention: Effects of Drugs on
Plasticity in Brain Injury
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• Drugs enhancing norepinephrine and
dopamine have consistently been shown to
accelerate recovery from brain injury.
• Stimulant medications
Effects of Drugs on Plasticity in Brain
Injury
• Cats and rats with brain injury who were given
stimulants combined with “physical therapy”
(forced beam walking) recovered motor
function more quickly and more completely
than controls.
Other Techniques to assist learning
after brain Injury
• EMG-triggered muscle stimulation: Movement is
initiated by patient and facilitated with electrical
stimulation.
• Robotic therapy: Patient attempts a movement.
Robot assists with completion of the movement,
increasing sensory input and motivation.
Practical Application
• Teach families that their daily interactions are
the most important therapy
• Motivate to provide regular brief periods of
stimulation
• Show how to integrate this stimulation into
daily routine
Practice skills in a fun and practical
manner.
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Put dishes in the dishwasher
Play with balls
Brush teeth
Play games
Play with play dough
Ride a trike
Play an instrument
Practical Application
• Involve kids in recreational activities
• Many adaptive programs available
Other Suggestions
• Explore and educate about techniques and
therapies in the community
• Put families in contact with other families
Activity to Promote Plasticity in Us
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Be active
Learn
Exercise
Keep an open mind
Play videogames