Introduction to Neuroplasticity & its application in neuro rehabilitation. This presentation is aimed at beginners in occupational therapy profession

1. Mr. Phinoj K Abraham (MOTh)
Assistant Professor,
SRM College of Occupational Therapy

2. (plastos) - ‚capable of being molded’
Neuroplasticity:
‘the ability of the CNS to remodel itself’
Neuroplasticity is how we adapt to changing
conditions, learn new facts, and develop new
skills.
It is constantly occurring; the brain is always
changing
(Mark Hallet 2005)

3. Neuroplasticity
Historical Background
Two Current Concepts
Importance in Rehabilitation
Role of Occupational Therapist
Related Research

5. Until 1970 : brain structure is relatively immutable in
adulthood.
In the 1960s,
Paul Bach-y-Rita - electrically stimulated chair with 400
vibrating stimulators for congenitally blind.
He Concluded, “We see with our brains, not with our eyes.”
Doidge, Norman (2007)

6. A tragic stroke that left his 68 year old father paralyzed
inspired Bach-y-Rita to study brain rehabilitation
His brother – a physician- rehabilitated him and he recovered
well
He believed that ‘Under conditions of interest, such as that
of competition, the resulting movement may be much more
efficiently carried out than in the dull, routine training in the
laboratory’
(Franz, 1921, pg.93)

7. David Hubel and Torsten Wiesel:
Study with kittens
The experiment involved sewing one eye shut and
recording the cortical brain maps
the portion of the kitten’s brain associated with the shut
eye was not idle, as expected. Instead, it processed visual
information from the open eye.
“… as though the brain didn’t want to waste any ‘cortical
real estate’ and had found a way to rewire itself.”

8. Jenkins & Merzenich (1987) removed monkey’s 1 Peripheral
Nerve , later found that adjacent neurons had started to
respond to the palm.

9. (Ramachandran V 1992).
“if someone were to lose their right
hand in an accident, they may then have
the feelings of a phantom limb because
the areas in the somatosensory cortex
that are near to the ones of the hand
(the arm and face) will take over (or
"remap") this cortical region that no
longer has input”

11. Enhancement of existing
connections
Formation of new
connections
Very active research area; concepts areare continully being updated
A very active research area; concepts continually being updated

12. Type
1.
Mechanism
Enhancement of existing connections
A. Synapse development
B. Synapse strengthening
2.
Duration
Physiological
Biochemical
ms-1 to hours
hours to days
Formation of new connections
A. Unmasking
B. Sprouting
Physiological
Structural
minutes to days
days to months

13. 1. Enhancement of existing connections
Increased use of a synapse in existing
pathways e.g. learning a new task
Or alternative pathways following
damage
Opposite: dendrite atrophy

14. Increased
afferent input
+
+
+
New synapses
evolve leading to
increased
excitation

15. Ragert et al., 2004

16. Effectiveness of a synapse can be increased for at least 3
durations:
1. Seconds and minutes
(short-term memory)
2. Hours and days
(intermediate-term memory)
3. Months and years
(long-term memory)
Such changes can take place at
three cellular locations:
1. Presynaptic terminal
2. Postsynaptic membrane
3. Postsynaptic nucleus
Kidd et al., 1992

17. Two point discrimination threshold in
pianists index finger
Ragert et al., 2004
R
L
Comparison of musicians to non-musicians
Findings were long-lasting piano practising resulted in lower spatial
discrimination thresholds in the index finger of piano players in
comparison to non-musicians.
This decrease in threshold was related to the number of hours
practised per day (>3 hours), not to the number of years they had
been playing

18. 2) Formation of new connections
Unmasking of pre-existing pathways
Sprouting of new pathways

19. Possible reasons why some synapses could
be ‘silent’
Inhibited by dominant pathways
Too little transmitter
Too few receptors
Don’t fire with other inputs

20. Parallel pathway; neurons
with a comparable role
Dominant pathway
Subservient pathway
+
+

21. Lesion to
dominant
pathway
Subservient pathway is
unmasked
+
Activity is
continued
despite
lesion
+

22. Cell body
Axon
Sprouting occurs
following damage or
denervation to the
nervous system and
is the growth of new
axons from cell
bodies forming new
pathways

23. INJURY
Following
denervation, neurotro
phic factors or nerve
growth factors are
released, they are
polypeptides capable
of promoting
neuronal survival.
lesion
Nerve
Growth
Factor
(NGF)

24. The release of
nerve growth
factors
stimulates
neurites or new
axons to sprout
and look for
the source of
the NGF
INJURY
Neurite induced
to sprout by
NGF
lesion
NGF

25. Injury results in
cell death
Cell is re-innervated
from alternative
stimulus
Sprouting may be a means of recovery; it may also produce
unwanted effects For example spinal cord injury patients may
experience strange sensations.

26. 1. Strengthen and develop
normal synapses
OT’st need to
2. Guide axonal sprouting
3. Facilitate unmasking of
alternative or previously
subservient pathways

27. Provide positive sensory input
i.e. “appropriate handling”
Facilitate “functional”
movement
Provide treatment at
“optimum” time
Education

28. NEGATIVE
PLASTICITY
Disuse/ unskilled
Noisy. nonspecific
POSITIVE PLASTICITY
Modulation
Not challenging
Outcome
Negative behaviors
Novel &
Challenging
Positive behaviors
Stimulation
Quality of
sensory
input
Intensive, skilled
Appropriate / specific

29. Mirror Therapy for patients with stroke & Amputation
Ramachandran, Rogers-Ramachandran & Cobb 1995
Hypothesis
Every time the patient attempted to move the paralyzed limb, they
received sensory feedback (through vision and proprioception) that
the limb did not move.
This feedback stamped itself into the brain circuit (Hebbian Learning)
So even when the limb was no longer present, the brain had learned
that the limb (and subsequent phantom) was paralyzed.
Often a phantom limb is painful because it is felt to be stuck in an
uncomfortable or unnatural position, and the patient feels they
cannot move it.

30. Mirror Box
To retrain the brain, and thereby
eliminate the learned paralysis
The patient places the good limb into
one side, and the stump into the
other
It appears as if the phantom limb is
also moving
to unclench it from potentially
painful positions.
(Ramachandran, Rogers-Ramachandran & Cobb 1995)

31. Ex.
“Examining the Neuroscience Evidence for SensoryDriven Neuroplasticity: Implications for SensoryBased Occupational Therapy for Children and
Adolescents”
Shelly J. Lane and Roseann C. Schaaf
American Journal of Occupational Therapy
May/June 2010 vol. 64 no. 3 375-390

32. Neuroplasticity is the focus of a growing body of
research with significant implications for neuro-
rehabilitation.
Neuroplasticity - while not a concept unique to
OT - holds tremendous application for neurorehabilitation provided by OTs.

33. Bibliography
Neurological Rehabilitation – Umphred Darcy 4th edition
Physiological basis of Rehabilitation
Journals
Mirror therapy improves hand function in subacute stroke: a
randomized controlled trial. Arch Phys Med Rehabil. 2008
Mar;89(3):393-8.
Guest Editorial - Neuroplasticity and rehabilitation assesssed from
www.rehab.research.va.gov/jour/05/42/4/pdf/hallet.pdf retrieved on 303-12
Net References
http://en.wikipedia.org/wiki/Neuroplasticity retrieved on 3-03-12
http://en.wikipedia.org/wiki/Mirror_box retrieved on 3-03-12
http://en.wikipedia.org/wiki/Hebbian_learning retrieved on 3-03-12