Neuroplasticity Following Sensory Loss

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Dr. Lofti Merabet discusses the incredible adaptability of the brain with the loss of one or more senses. (NDA International Conference, 2009)

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Neuroplasticity Following Sensory Loss

  1. 1. The Boston Retinal Implant Project Center for Noninvasive Brain Stimulation Center for Innovative Visual Rehabilitation Harvard Medical School Boston VA Medical Center Beth Israel Deaconess Medical Center www.bostonretinalimplant.org www.tmslab.org
  2. 2. Are the Blind Really Better? Auditory Tactile 1.5 JVP Domes 1.4 Threshold 1.3 1.2 1.1 1.0 0.9 Gougoux et al. Nature, 2005 Blind Sighted 1.2 1.1 Verbal Memory Threshold 1 0.9 0.8 0.7 Reading Homol Non-Dom Non-Dom Homologous van Boven et al. Neurology 2000 Amedi et al. Nat Neurosci 2003; 2004
  3. 3. "we only use about 30% of our brains"…???
  4. 4. TOUCH MOTOR SPATIAL AWARNESS WORKING MEMORY VISION SMELL TASTE HEARING SPEECH
  5. 5. TOUCH SPATIAL AWARNESS WORKING MEMORY VISION HEARING
  6. 6. Watching the Brain in Action: Functional Neuroimaging RESTING TASK Task Rest Difference - = Generating Verbs Speaking Words Hearing Words Seeing Words from Posner and Raichle
  7. 7. Activation of Occipital (Visual) Cortex in the Blind Braille Sound Localization Verbal Memory Sadato, Pascual-Leone et al., Nature: 1996; Brain: Gougoux et al., 2005 PLoS; Nature 2004 Amedi et al. Nat Neurosci 2003; 2004 1998
  8. 8. Occipital Visual Cortex: Early vs. Late Blind EARLY BLIND LATE BLIND Burton et al., J. Neurophysiol: 2002
  9. 9. The Blindfold Experiment: Tactile Day 5 > Day 1 Blindfold vs Non Blindfold Pascual-Leone et al., 2003 Merabet et al., PLOS One 2008
  10. 10. The Blindfold Experiment: Tactile Right Hand (reading) 50 40 Braille Character Recognition 30 [% errors] 20 Blindfolded: Training Non Blindfolded: Training 10 0 Day 1 Day 3 Day 5 Kauffman et al., Neuroreport 2002
  11. 11. Braille Alexia Following an Occipital Stroke Case Report: - 63 y.o. right-handed female - blind at birth (retinopathy of pre-maturity) - Reported VA: No Light Perception OU - normal milestones, Braille at 6 y.o. - proficient reader: 120-150 symbols/min Complaint: light-headedness, difficulty swallowing, loss of motor coordination, LOC - admitted to emergency - 24 hr coma - “normal physical and neurological exam” - within 24 hrs; alert and interactive From Hamilton et al., 2000; Neuroreport
  12. 12. Transcranial Magnetic Stimulation (TMS): "virtual brain lesions" Generated Magnetic Induced Field Current TMS Coil Low frequency (e.g. 1 Hz) = lowered excitability High frequency (e.g. 10-20 Hz) = increased excitability
  13. 13. Modulating Braille Reading Performance by Modulating Brain Activity Low frequency Tactile and linguistic manifestations of "visual" cortex modulation High frequency Roy H. Hamilton and Alvaro Pascual-Leone TICS 1998
  14. 14. “Painting is a blind man’s profession, as blind people have a clearer vision of reality” - Picasso “I wish I had been born blind, because it would have enhanced my artistic perception of the world” - Monet
  15. 15. Esref Armagan www.armagan.com
  16. 16. Drawing vs. Scribbling Amedi et al., 2008
  17. 17. Activation of Occipital (Visual) Cortex in the Blind Braille Sound Localization Verbal Memory Sadato, Pascual-Leone et al., Nature: 1996; Gougoux et al., 2005 PLoS; Nature 2004 Amedi et al. Nat Neurosci 2003; 2004 Brain: 1998 Activation of Auditory Cortex in the Deaf Sign Language Motion Perception Vibro-tactile + Nishimura et al., Nature, 1999 Finney et al., Nat Neurosci, 2001 Auer et al., Neuroreport, 2007
  18. 18. Helen Keller Anindya “Bapin” Bhattacharyya http://www.bapin.info/index.html
  19. 19. Communicating with Bapin:
  20. 20. Functional Neuroimaging: ASL (word>non word) A.B. S.W. Diffusion Tensor Imaging
  21. 21. Wayfinding, Navigation and Cognitive Mapping
  22. 22. target virtual world reconstruction final representation Jaime Sanchez and Coworkers C5: University of Chile, Santiago http://www.c5.cl/audio/pags/softwares/audio_doom/audiodoom_metod.htm
  23. 23. stairwell exit table furniture door First Floor monster First Floor player (facing north) jewel Second Floor Second Floor
  24. 24. Transfer of Navigation Skills Learned with AbES to Real World Virtual World Real World Outcome Measures Quantitative: classroom 10 - time to target - # of mistakes made path taken Qualitative: lobby -type of errors made entrance - strategies employed breakdown statistics of path -"creativity" and problem solving
  25. 25. AbES and Functional Neuroimaging instructions vs rest AbES projected auditory reflecting on a screen mirror cortex goal-directed navigation vs rest parietal cortex frontal cortex subject visual control keys wearing cortex headphones posterior hippocampus
  26. 26. Audio-Haptic Doom and crossmodal interfacing
  27. 27. Other Software: University of Chile, Department of Computer Science
  28. 28. Artist Bernardo Strozzi (Italian, Genoese, 1581–1644) Title Tobias Curing His Father's Blindness
  29. 29. Case Report: Subject M.M. - monocular, and at age 3 blinded in fellow eye from a chemical burn. Undergoes corneal transplant at childhood; unsuccessful. - some light perception, no experience of form or contrast perception. Reports no visual memories or imagery. - at 43 y.o., undergoes corneal/limbal stem cell transplant. - highly motivated, intelligent individual. courtesy the Discovery Channel
  30. 30. The Retinal Approach VITREOUS NFL GANGLION CELLS BIPOLAR CELLS PHOTORECEPTORS SUB RETINAL RPE CHOROID
  31. 31. Video courtesy of Second Sight www.2-sight.com
  32. 32. ? ? ? Cross-modal Adapted Occipital cortex Visual Occipital cortex maximal visual maximal cross-modal function adaptation Factors: Onset Duration Type of Vision Loss Prior Experience Rehabilitation Strategy Merabet et al., 2006
  33. 33. correlation between degree of hypometabolism and success …Corollaries and Lessons Learned… with a CI. imaging is prognostic other regressors: -duration of deafness, -duration of CI use Auditory Cortex *resting hypometabolism and not cross-modal activation * pre-lingual deaf children Nishimura et al., Nature, 1999 Nature Lee et al., 2001 Nature
  34. 34. …Corollaries and Lessons Learned… Brain Machine Interfaces www.cyberkineticsinc.com left (intact) right (amputated) Ersland et al., NeuroReport 8, 207–210 (1996)
  35. 35. TASTE TOUCH VISION HEARING SMELL
  36. 36. TASTE TOUCH HEARING SMELL
  37. 37. Jaime Sanchez, PhD University of Chile Alvaro Pascual-Leone, MD PhD Ela Bhatt, PhD Mark Halko, PhD Souzana Obretenova Center for Noninvasive Brain Stimulation Joseph Rizzo, MD Boston Retinal Implant Project Carroll Center for the Blind Boston University Center for Biomedical Imaging Our patients…

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