1. Mirrored, imagined and executed movements differentially activated sensorimotor cortex in amputees with and without phantom limb pain
Martin Diers, et al. 2010

2. Phantom Limb Pain Phantom Sensations Phantom Pain
Can occur anywhere but most common in amputated limbs
50-85% of people with amputated limbs experience phantom limb pain

3. Theories CNS PNS Cortical Reorganization and Neuroplasticity
Body Schema
Neuromatrix Theory
…others…
PNS
Ex. neuromas

4. Cortical Reorganization and Neuroplasticity
Penfield sensory (left) and motor (right) homunculi (Penfield and Boldrey, 1937).

5. Cortical Reorganization cont.
Used microelectrodes to prove cortical plasticity.
When 1 finger was amputated, the sensory input from adjacent digits took over
The amount of cortical reorganization has been found to be dependent upon the size of the deafferented region(s)
Mr. and Mrs. Owl Monkey

6. More Cortical Reorganization
When the ipsilateral face was touched, patient felt touch on face and hand.

7. “If I’m in a buttload of pain, I need a buttload of pills.”
Dr. Gregory House
Head of Diagnostic Medicine
Princeton-Plainsboro Teaching Hospital

8. Treatment Options for PLP
Pharmaceuticals
Opioids
Anticonvulsants
Lidocaine/mexiletine
Clonidine
Ketamine
Amitriptyline
Nonsteroidals anti-inflammatory drugs
Calcitonin

9. More Treatments TENS Deep brain and spinal cord stimulation
Acupuncture
Virtual reality
Mirror visual feedback

10. Video Clip House: Mirror therapy

11. What are Mirror Neurons?
Empathy neurons
Monkey see- monkey do.
Frontal and parietal lobes
Vision dominates touch and proprioception (Rock and Victor, 1964)
vision dominates = ‘visual capture’

12. Video Clip American’s Got Talent Magic Tricks

13. Hypothesis
Mirrored movements of the intact hand might provide input into the cortical representation zone that previously received input from the now amputated limb (i.e. cortical reorganization),
and, executed and imagined movements might have similar but less pronounced effects.

15. Design Executed (with dominant or intact hand) Mirrored
Imagined (non-dominant or amputated hand)

16. fMRI 1990’s Measures hemodynamic response (changes in blood flow)
Blood flow and blood oxygenation in brain is related to neural activity.
Metabolism- neurons don’t store blood & oxygen
Disadvantages- Correlation does not imply causation

18. Mirrored
Activation of the sensorimotor cortex contralateral to the hand seen in the mirror in the nonPLP and the HC but not in the PLP.

19. Executed
Activation of the contralateral sensorimotor area in all three groups but ipsilateral cortex was only activated in the nonPLP and HC group.

20. Imagined
Imagined movement activated the supplementary motor are in all groups and the contralateral primary sensorimotor cortex in the nonPLP and HG but not in the PLP

22. Results
Imagined movement in all three groups showed activation in the supplementary motor cortex.

23. * * *

24. Conclusions
Viewing one’s own hand in a mirror produces activity in sensory and motor cortices contralateral to the hand that is perceived.
The larger the shift of neighboring activations into the cortical amputation area, the more pain was present.