Motor Skill Learning and Brain Plasticity - Plone site · UNIVERSITY OF JYVÄSKYLÄ Motor Skill Learning and Brain Plasticity Janne Avela & Susanne Kumpulainen Neuromuscular Research

UNIVERSITY OF JYVÄSKYLÄ

Motor Skill Learning and Brain Plasticity

Janne Avela & Susanne Kumpulainen

Neuromuscular Research Center, Department of Biology of Physical ActivityUniversity of Jyvaskyla, Finland

Brain Plasticity

Brain's ability to change at any time and age – for better or worse• Plasticity of the brain is important for learning, memory,

motor adaptation and recovery from brain injury

Rapid plastic changes:• Activity dependent synaptic plasticity (Jacobs & Donaghue 1991)

• Long-term potentiation (LTP)• Long term depression (LTD)

• Activation of existing but silent synapses (Liao et al. 1999)

Morphological plastic changes (Kleim et al. 1996):• Synaptogenesis • Neurogenesis

Brain Plasticity Changes Induced by Long -term Physical Exercise

� Regular physical exercise� Global benefits to the brain:

• Increases brain plasticity(for review see Kramer and Erickson 2007)

• Improves neurocognitive functions

� Different types of physical exercise� Experience-specific adaptation in the

corticospinal system (for review see Adkins et al. 2006)

Animal experiments

Allison C. and Pratt. Neuropsychopharmacology(2006) 31, 602–619.

Intracortical microelectrode stimulation

Human experiments• Baised on imaging and mapping techniques

fMRITMS

MEGEEG

Magnetic stimuli produce a motor evoked potential ( MEP) in the target muscle

EMG

Trancranial magnetic stimulation

to study the cortical motor areas targeting long finger flexor and extensor muscles in subjects learning a one-handed, five-finger exercise on the piano.2 hours x 5 days

• Changes in the excitability and reorganisation in the representation of the corticomotor projection to the hand in a group of elite athletes

• Absence of any such changes in a group of social players suggests that long-term reinforcement and constructive practice of skilled motor tasks can lead to functional plasticity of the corticomotor projection

Brain Plasticity

Brain's ability to change at any age – for better or worse• Plasticity of the brain is important for learning, memory,

motor adaptation and recovery from brain injury

Rapid plastic changes:• Activity dependent synaptic plasticity (Jacobs & Donaghue 1991)

• Long-term potentiation (LTP)• Long term depression (LTD)

• Activation of existing but silent synapses (Liao et al. 1999)

Morphological plastic changes (Kleim et al. 1996):• Synaptogenesis ?• Neurogenesis

Paired Associative Stimulation (PAS)

Activity -dependent SynapticPlasticity

Ability of sensory and motor cortices to dynamically reorganize

“‘Coincident activity in two connected neurons leads to strengthening of their connection”

Hebb 1949

• Potentiation takes place if the postsynaptic neuron fires an action potential after the excitatory postsynaptic potential is induced by the presynaptic neuron

Long-term potentiation (LTP)

Paired Associative Stimulation (PAS)

(Stefan K, Kunesch E, Cohen LG, Benecke R, Classen J. (2000) Brain. 2000 Mar;123 Pt 3:572-84)

PAS is a non-invasive method developed to induce bidirectional changes in the excitability of the cortical projections to the target muscle

Based on Hebb’s law

An electrical stimulation of peripheral somatosensory afferents paired with TMS over the contralateral motor cortex

PAS for brain rehabilitation

Non-invasive cortical stimulation

+ +-

“Early motor learning = LTP-like mechanisms are used to increase performance after short-term motor practice.”

“Late motor learning = supported by synaptogenesis, which leads to enhanced corticospinal and intracortical

recruitment.”

PAS reacts on both, LTP-like mechanisms and synaptogenesis

To investigate the effects of skill and endurancetraining background on motor cortex plasticity

Skill group:

• 11 Dancers

• 2 FigureSkaters

• 2 Gymnasts

Endurance group:

• 8 Cross-Country Skiers

• 4 Orienteerers

• 3 Runners

Subject Data

Skill group Endurance group

Subjects (f/m) 15 (12/3) 15 (10/5)

Age 23 26

Height 166 cm 172 cm

Weight 60 kg 62 kg

Output 51 % 54 %

Training years 14 12

Training/week 8 h 10 h

Competitors 10 15

Methods - Protocol

PAS-intervention

POST

* TMS x10- Passive muscle

* SLR x10- 20 % 0f MVC

PRE

* MVC x 3* SEP

* TMS x10- Passive muscle

* SLR x10- 20 % 0f MVC

Results – Motor Evoked Potentials

SKILL

ENDURANCE

PRE-MEP

POST-MEP

176%

93%

0%

50%

100%

150%

200%

250%

300%

Skill Endurance

Results – Short Latency Stretch Reflex

40 ms

0.4

mV

BaselinePost

SKILL

ENDURANCE

0

0.5

1

1.5

2

Skill Endurance

No

rm

alized

SLR

Baseline

Post

SKILL ENDURANCE

� Significant LTP-like plasticity in skill group but not in endurance group

�Different training induced adaptations in the motor cortex

• Skill training → increased synapse number →

greater potential for plasticity (Rosenkranz et al. 2007)

• Endurance training → best possible efficiency →

automatic movements (Doyon and Benali 2005) →

subcortical loops → Reduced use of motor cortex

Discussion

Practical implications

For Brain Rehabilitation :• Versatile skill training for

synaptogenesis• Endurance training for

angiogenesis

Combination!!!!

Practical implicationsFor Sport:• Versatile skill training• To create motor learning potential• In order to learn sport spesific technigue

Thank you!

LTP

Cooke S. F. and Bliss T. V. P. (2006): Plasticity in the human central nervous system. Brain, 129, 1659–1673

• N-methyl-D-aspartate (NMDA) receptor binds glutamate• Influx of calcium ions