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8/17/2019 Logo Ped Kur Suu Maj 2010
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Plasticity of the nervous system
- “an old concept with a new meaning” –a brief introduction …
Jörgen Borg MD PhD
Department of linical !ciences" #eha$ilitation Medicine
%arolins&a 'nstitutet" Danderyd (ospital
!toc&holm" !weden
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Plasticity of the nervous system
• fundamental for learning andrelearning - reha$ilitationinterventions
• evolving in parallel with $asicand clinical neuroscience
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“Plasticity”
• Plasticity – the ability to be moulded /shaped ( from )ree& ”plastos” *
• Neuroplasticity
• Brain plasticity
• Peripheral nerve system plasticity
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“Brain plasticity” – introduced $y
• +illiam James ,./0-12*
3 4merican psychologist
and philosopher
• $rain functions are not fi5ed
throughout life ,Principles of
Psychology .12*
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3eurons and their
communication666
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3erve cells visualised
• !antiago #am7n y a8al,.90 –1:/* !panishhistologist" 3o$el laureate12;
• microscopic structure ofnerve cells and synaptic cleft
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!ynapse
• ”!ynapse< from )ree&
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3eurotransmission@modulation
• (enry Dale - identified acetylcholinein 1/
• Atto ?oewi ,.=: –1;* laterdemonstrated its role in the nervous
system
• 3o$el laureates 1:;
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!ynaptic plasticity- “(e$$ian
learning”
• Donald (e$$ ,12/ –1.9*" anadian
psychologist
•“6 66two cells or systems of cells that arerepeatedly active at the same time willtend to $ecome associated" so thatactivity in one facilitates activity in theother6“ ,1/1*
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!ynaptic strength - ?ong Cerm
Potentiation and Depression
• Cer8e ?mo 1;;E synaptic long-lasting@long-termpotentiation @?CP - increase in the synapticstrength of neurons in hippocampus followingelectrical stimulation
• change of postsynaptic cells sensitivity to inputfrom presynaptic cells
•
?CP and ?CD important mechanisms for learningand memory
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3ew synapses
• - in response to e5periences in normal $rain
•- from dendritic and a5onal sproutes in in8ured $rain
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ortical networ&s - in response to
manipulated input to normal brain
• 'n e5perimental animalsE
• Plasticity in visual corte5 – “critical period”
Hubel DH, iesel !N"#$%&ies
• Plasticity in auditory andsomatosensory corte5 'erenich '' and
Bla)e D!
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ortical networ&s - in response to in*ury
in e+perimental animalsE
“!pared regions ad8acent to the infarctand far removed from the infarctundergo functional alterations that aremodified $y $ehavioural e5perience
?ong-range intracortical pathways can
$e rerouted to completely novel
territories” andolph " Nudo,
e.iring of intracortical path.ays after
ischemic in*ury to '#" tro)e" 0&&12345part06748&-489":
• Hand motor map in mon)ey
postin*ury and .ith no training o
.ith training (Nudo , #$$1 'o
Psychiatry:"
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SMA
F
G
3
C'
A
3
Intervention
Cime after 'n8ury : mo ; mo
linical o$servations – reclaiming
function666
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linical recovery and plasticity
• 3umerous studies have descri$ed the recovery curve ofvarious functions in patients with stro&e and CB'
• orrelates with reorganisation of networ&s - asdemonstrated $y an increasing num$er of imaging studies -
since the pioneering studies $y hollet F et al @P>C" ao H etal@fM#' in the 112-ies
• #eorganisation depends on age at in8ury" time since in8uryand interventions
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#eorganisation of motor networ&s early
in life - role of ipsilateral motor corte5
Cwo types of ipsilateral reorganiIation in congenital hemiparesisE
a CM! and fM#' study6 taudt ', ;rodd , ;erloff
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Dynamic changes of networ&s in adults
at various time points after stro&e
Chree phasesE a strongly reduced activationof remaining left languageareas in the acute phase is follo.ed by
an up regulation .ith
recruitment of homologuelanguage ones, .hichcorrelates .ith languageimprovement…
a normaliation of activation isobserved, possibly reflecting
consolidation in thelanguage system"
!aur et al 022;
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@nterventions - Cctivity dependent
• 3umeral studies have
demonstrated reorganisationof $rain activity pattern inresponse to
• 'ntense training of motor and
cognitive tas&s• 'magination of movements
• Functional relevanceconfirmed $y virtual CM!lesions
?ind$erg P) et al6 se-dependent up- and do.n-regulation ofsensorimotor brain circuits in stro)e patients"7 Neurorehabil Neural epair" 0&&1 ul-Cug20#(8:73#9-0%"
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Behind todays concept66
• Huge number of observational and e+perimental studies
• East t.o decades7
• Human brain net.or)s related to sensory-motor" speech-cognitive functions" emotions and “consciousness”
• eorganisation of these net.or)s in response to in8ury andinterventions
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#eferences in Pu$Med 4pril 022
• 3europlasticity 04 0%4 (F$&G after #$$&:
• Brain plasticity 08 191• !ynaptic plasticity #9 &&$
• fM#' and plasticity # 0&%
• P>C and plasticity #%%
• ?earning and plasticity 4 813
• Motor recovery and plasticity 4%$
• Pain and plasticity # 398
• CM! and plasticity 089
• D! and plasticity 13
•
ehabilitation and plasticity # #04
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urrent meaning of $rain plasticity in
reha$ilitation medicine
•Functional improvements after an acKuired $rain in8ury areparalleled $y reorganisation of cere$ral networ&s
• !uch reorganisation is activity driven – new technologies may $esupportive ,also in order to avoid “maladaptive” plasticity*
• Functional imaging will soon $e part of routine functionaldiagnostic set up and used to design individualised interventions,*