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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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www.tmslab.org
Center for Noninvasive Brain StimulationHarvard Medical School
Beth Israel Deaconess Medical Centerwww.bostonretinalimplant.org
The Boston Retinal Implant ProjectCenter for Innovative Visual Rehabilitation
Boston VA Medical Center
Are the Blind Really Better?
Tactile
Auditory
0.7
0.8
0.9
1
1.1
1.2
Reading Homol Non-Dom Non-DomHomologous
Thre
shold
van Boven et al. Neurology 2000
0.9
1.0
1.1
1.2
1.3
1.4
1.5
Blind Sighted
Thre
shold
JVP Domes
Gougoux et al. Nature, 2005
Verbal Memory
Amedi et al. Nat Neurosci 2003; 2004
"we only use about 30% of our brains"…???
TASTESPEECH
HEARING
VISION
SPATIAL AWARNESS
TOUCHMOTOR
WORKING MEMORY
SMELL
HEARING
VISION
SPATIAL AWARNESS
TOUCH
WORKING MEMORY
Watching the Brain in Action: Functional Neuroimaging
from Posner and Raichle
RESTING TASK
Generating Verbs
SpeakingWords
HearingWords
SeeingWords
Task Rest Difference
- =
Activation of Occipital (Visual) Cortex in the Blind
Sadato, Pascual-Leone et al., Nature: 1996; Brain:1998
Gougoux et al., 2005 PLoS; Nature 2004 Amedi et al. Nat Neurosci 2003; 2004
Braille Sound Localization Verbal Memory
EARLY BLIND LATE BLIND
Burton et al., J. Neurophysiol: 2002
Occipital Visual Cortex: Early vs. Late Blind
Day 5 > Day 1Blindfold vs Non Blindfold
Pascual-Leone et al., 2003 Merabet et al., PLOS One 2008
The Blindfold Experiment: Tactile
The Blindfold Experiment: Tactile
Kauffman et al., Neuroreport 2002
Right Hand (reading)
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10
20
30
40
50
Bra
ille
Cha
ract
er R
ecog
nitio
n[%
erro
rs]
Day 1 Day 3 Day 5
Blindfolded: Training
Non Blindfolded: Training
Case Report:
From Hamilton et al., 2000; Neuroreport
- 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
Braille Alexia Following an Occipital Stroke
Transcranial Magnetic Stimulation (TMS): "virtual brain lesions"
TMS Coil
Low frequency (e.g. 1 Hz)= lowered excitability
High frequency (e.g. 10-20 Hz)= increased excitability
Induced Current
GeneratedMagnetic
Field
Modulating Braille Reading Performance by Modulating Brain Activity
Roy H. Hamilton and Alvaro Pascual-Leone TICS 1998
Tactile and linguistic manifestationsof "visual" cortex modulation
Low frequency
Highfrequency
“I wish I had been born blind, because it would have enhanced my artistic perception of the world”
“Painting is a blind man’s profession, as blind people have a clearer vision of reality”
- Picasso
- Monet
Esref Armaganwww.armagan.com
Drawing vs. Scribbling
Amedi et al., 2008
Activation of Auditory Cortex in the Deaf
Nishimura et al., Nature, 1999 Finney et al., Nat Neurosci, 2001 Auer et al., Neuroreport, 2007
Activation of Occipital (Visual) Cortex in the Blind
Sadato, Pascual-Leone et al., Nature: 1996; Brain: 1998
Gougoux et al., 2005 PLoS; Nature 2004 Amedi et al. Nat Neurosci 2003; 2004
Braille Sound Localization Verbal Memory
Sign Language
+
Motion Perception Vibro-tactile
Anindya “Bapin” Bhattacharyya
http://www.bapin.info/index.html
Helen Keller
Communicating with Bapin:
Functional Neuroimaging: ASL (word>non word)
A.B.
Diffusion Tensor Imaging
S.W.
Wayfinding, Navigation and Cognitive Mapping
Jaime Sanchez and CoworkersC5: University of Chile, Santiagohttp://www.c5.cl/audio/pags/softwares/audio_doom/audiodoom_metod.htm
target virtual world reconstruction final representation
player (facing north)
monster
jewel
door
table furniture stairwell exit
First Floor
Second Floor
First Floor
Second Floor
Transfer of Navigation Skills Learned with AbES to Real World
breakdown of path
path taken
statistics
lobbyentrance
classroom10
Virtual World Real World
Quantitative:- time to target- # of mistakes made
Qualitative:-type of errors made- strategies employed-"creativity" and problem solving
Outcome Measures
AbES and Functional Neuroimaging
AbES projectedon a screen
control keys
reflecting mirror
subject wearing
headphones
instructions vs rest
auditorycortex
goal-directed navigation vs rest
frontalcortex
visualcortex
parietalcortex
posteriorhippocampus
Audio-Haptic Doom and crossmodal interfacing
Other Software: University of Chile, Department of Computer Science
Artist Bernardo Strozzi (Italian, Genoese, 1581–1644)Title Tobias Curing His Father's Blindness
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
CHOROIDRPE
PHOTORECEPTORS
GANGLION CELLS
VITREOUS
BIPOLAR CELLS
NFL
SUB RETINAL
The Retinal Approach
Video courtesy of Second Sightwww.2-sight.com
maximal visualfunction
maximal cross-modaladaptation
?? ?
Cross-modal AdaptedOccipital cortex
Visual Occipital cortex
Factors:Onset
DurationType of Vision LossPrior Experience
Rehabilitation Strategy
Merabet et al., 2006
…Corollaries and Lessons Learned…
Nishimura et al., Nature, 1999
Lee et al., 2001 Nature
Nature
Auditory Cortex
correlation between degree of hypometabolism and successwith a CI. imaging is prognosticother regressors:-duration of deafness,-duration of CI use
*resting hypometabolism and notcross-modal activation* pre-lingual deaf children
…Corollaries and Lessons Learned…
www.cyberkineticsinc.com
Brain Machine Interfaces
Ersland et al., NeuroReport 8, 207–210 (1996)
left (intact) right (amputated)
TOUCH
HEARING
TASTE
SMELL
VISION
TOUCH
HEARING
TASTE
SMELL
Jaime Sanchez, PhDUniversity of Chile
Alvaro Pascual-Leone, MD PhDEla Bhatt, PhD
Mark Halko, PhDSouzana Obretenova
Center for Noninvasive Brain Stimulation
Joseph Rizzo, MDBoston Retinal Implant Project
Carroll Center for the Blind
Boston University Center for Biomedical Imaging
Our patients…