The Cerebellum & Motor Learning:The Cerebellum & Motor Learning:Experimental Design Considerations

Rachael D. Seidler, Ph.D., University of MichiganDepartment of Psychology, School of Kinesiology, & Neuroscience Program

Does the cerebellum mediate motor l i t ti b th?learning, motor execution, or both?

Performance improves across trials p(faster, more accurate movements)

But, cerebellar activity varies with movement d f & i th b fspeed, force, & accuracy in the absence of

learning….

• Spraker et al. (in press) Neuroimage• Vaillancourt et al. (2006) J Neurophys• Seidler et al. (2004) Neuroimage• Kitazawa et al. (1998) Nature• Van Mier et al. (1998) J Neurophys

How can we disentangle performance f l i ff t i th b ll ?from learning effects in the cerebellum?

• Experimental design manipulations:p g p– Flatten the learning curve without affecting learning– Control conditions which vary speed, accuracy,

force, etc., subtract activation / test for interactions

Examples for two types of motor learningp yp g

S l i• Sequence learning• Sensorimotor adaptation

Typical sequence learning dataTypical sequence learning data

Response Time / Errors

R S S S S R S RR S S S S R S R

Dual task performance: temporary suppression of performance changessuppression of performance changes

ResponseResponse Time

R S S S S R S R

“Learning”Dual task

“Expression of Learning”

Si l t kSingle task

Behavioral resultsBehavioral results

400 * *

R350

400

Response Time 300

200

250

200R S S S S R R S R

LearningDual task

ExpressionSingle task

Block*p<.01

Seidler et al. (2002) Science

Time course of cerebellar activationTime course of cerebellar activation

lLD

Sig

na

R S S S S R R S R

BO

LearningDual task

ExpressionSingle taskBilateral H VI

Seidler et al. (2002) Science

Another approachAnother approach• Orban et al. (2010) Neuroimage

– sequence learning– sequence execution– speed control condition

Cerebellum HVIIIperformance only

Cerebellum HVIPerformance & learning

Sensorimotor AdaptationSensorimotor Adaptation

Movement Trajectoriesj

Early learning Late learningy g g

Sensorimotor Adaptation

Direction Error

15

eg)

5

5

Erro

r (de

-15

-5

irect

ion

-25

15D

Block

Imamizu et al. 2000 Nature

Adaptation or execution / performance effects?Adaptation or execution / performance effects?H IV / V

H VH V

Seidler et al. (2006) Exp Brain Res

Control experiment: movements to smaller (target 1) or larger (target 4) targets(target 1) or larger (target 4) targets

Seidler et al. (2004) Neuroimage

Start Variable target sizes

Cerebellar activity is highest for smaller t t / l / l ttarget / larger errors / slower movements

Seidler et al. (2004) Neuroimage

What about transfer of learning effects?What about transfer of learning effects?

Seidler & Noll (2008) J Neurophys

Conclusion: Dissociable cerebellar regions contribute to motor learning and motor executionBut, how does the cerebellum contribute to motor learning?to motor learning?

What role(s) does the cerebellum ( )play in motor learning?

Bo et al. (2011) Neuroimage

Interleaved MR acquisition & vocal responses

Bo et al. (2011) Neuroimage

Greater cerebellar activity for symbolic than spatial conditions, correlates with symbolic learning magnitude

Bo et al. (2011) Neuroimage

ConclusionsConclusions

C b ll l l i t• Cerebellum plays a role in motor execution and learning

• Role & subregions are task dependent• For sequence learning: supports q g pp

symbolically cued learning (high S-R complexity)p y)

•Acknowledgements:Acknowledgements:

• Funding: NIH AG 24106• Collaborators:

Doug Noll (BME, Radiology), Scott Peltier (BME, g ( gy) (FMRI lab), & Jin Bo (EMU Psychology)