Differentially Able Rather Than Disabled

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Differentially Able Rather Than Disabled
Lotfi B. Merabet
Laboratory for Magnetic Brain Stimulation BI
Deaconess Medical Center Harvard Medical
School and The Boston Retinal Implant
Project Massachusetts Eye and Ear Infirmary and
Center for Innovative Visual Rehabilitation,
Boston VA
Laboratory for Magnetic Brain
Stimulation
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Visual Deprivation
Visual Substitution
Visual Restoration
- neuroplasticity and adaptations
following blindness "potential of the brain"
- "sight" through the remaining
senses "adaptive strategies and assistive
technologies"
- Retinal Prosthesis Program "functionality
and useful vision"
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Visual Deprivation
Visual Substitution
Visual Restoration
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(No Transcript)
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How do they do it?
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Review of Neurology 101
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TOUCH
MOTOR
SPATIAL AWARNESS
WORKING MEMORY
VISION
SMELL
COORDINATION
TASTE
SPEECH
HEARING
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The Visual System
to see to know what is where by
looking -Aristotle
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The Visual System
Occipital (Visual) Cortex
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The Visual Systemspecialization
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The Visual Systemdivision of labour
WHERE?
WHAT?
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TOUCH
MOTOR
SPATIAL AWARNESS
WORKING MEMORY
VISION
SMELL
COORDINATION
TASTE
SPEECH
HEARING
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TOUCH
VISION
HEARING
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What is the point of having a visual cortex if
you are blind?
M Sereno MGH Neuroimaging Center
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Watching the Brain in Action Functional
Neuroimaging
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Functional Neuroimaging Activation of Occipital
(Visual) Cortex
Sadato, Pascual-Leone et al., Nature 1996
Brain 1998
Gougoux et al., 2005 PLoS Nature 2004
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Neuroimaging of Occipital Cortex in the Blind
Braille
LATE
EARLY
Burton et al., J. Neurophysiol 2002
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Braille Alexia Following an Occipital Stroke
Case Report
- 63 y.o. right-handed female - blind at birth
(retinopathy of prematurity) - Reported VA
NLP - normal milestones, Braille at 6 y.o. -
proficient reader 120-150 symbols/min
Complaint light-headedness, difficulty
swallowing, motor coordination, LOC - admitted to
Emergency - within 24 hrs alert and
interactive - normal physical and neurological
exam
Hamilton et al., 2000 Neuroreport Merabet et
al., 2004 Neuron
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Transcranial Magnetic Stimulation (TMS)
Generated Magnetic Field
Induced Current
TMS Coil
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Timing of Tactile Performance Early Blind
Effect of Chronometry on Braille Reading
Number of Stimuli
Somatosensory Cortex
10
20
30
40
50
60
70
80
90
100
110
Detected
No TMS
or
Perceived
Occipital Cortex
10
20
30
40
50
60
70
80
90
100
110
No TMS
Delay Interval (msec)
Pascual-Leone et al., 1999 Neuronal Plasticty
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Neuroplasticity of Somatosensory Cortex in the
Blind
After Training
Before Training
Pascual-Leone et al., 1999
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Neuroplasticity of Somatosensory Cortex in the
Blind
Sterr et al., 1998
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Pietrini et al., PNAS 2004
Identifying Objects Through Touch
Tactile Visual Overlap
tactile and visual
tactile
visual
Blind Subjects
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Verbal memory/Verb generation in blind and sighted
Early Blind
Sighted
Error Rate
Stimulation Site
Stimulation Site

• rTMS in the occipital cortex of the blind
  interferes with verb-generation performance
• most common error type was semantic.

Amedi et al. Nat Neurosci 2004
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Absolute pitch in blind musicians
Right Hemisphere
Higher prevalence of absolute pitch in blind
musicians (55) compared to sighted musicians
(20) despite later musical training.
Left Hemisphere
planum temporale
Hamilton et al., 2004
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Art in the Blind Evidence for a Spatial Sense
Creation AEB (Art Education for the Blind)
J. Kennedy
H. Bertolo et al., 2003
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Lisa Fittipaldi www.lisafittipaldi.com
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Esref Armagan
http//www.mersina.com/gallery/armagan/
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Drawing versus Scribbling
DRAWING
VERBAL MEMORY
SEEING
EARLY BLIND
SIGHTED
E.A.
Amedi et al., 2005
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The Blindfold Experiment
Pascual-Leone et al., 2003
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Day 5 (blindfold)
Day 5 (blindfold removed)
- left tactile object - left sensory control -
right tactile object - right sensory control -
verbal memory
Pascual-Leone et al. Ann Rev Neurosci, 2005
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Braille Reading Performance
50
45
40
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Braille Character Recognition errors
30
25
Blindfolded
20
Control
15
Day 1
Day 3
Day 5
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Lessons Learned
Auditory Cortex
Nishimura et al., Nature, 1999 and Lee et al.,
Nature 2001
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Sensory Substitution Devices
Laser cane
Tactile Visual Sensory Substitution (TVSS)
Tongue Display Unit (TDU)
Paul Bach-y-Rita
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Dot View KGS Corporation
Tactile shape and object perception
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The vOICe
http//www.seeingwithsound.com/voice.htm
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"The Rules" 1) Elevation frequency 2) Azimuth
stereo panning (inter-aural delay) 3)
Brightness loudness
hi
frequency
loudness
lo
hi
lo
time
left
right
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Object-Spatial Recognition Task
vs.
vs.
same object, same place
same object, different place
vs.
vs.
different object, same place
different object, different place
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DORSAL
VENTRAL
Amedi et al., 2005
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Audio Doom
Jaime Sanchez University of Chile Santiago, Chile
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Audio Doom
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Project Prakash
Pawan Sinha Professor MIT
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Sight Restorationwith a RetinalProsthesis
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The Retinal Approach Epiretinal vs Subretinal
The "Scoreboard" Approach
LIGHT
EPI RETINAL
GANGLION CELLS
BIPOLAR CELLS
SUB RETINAL
PHOTORECEPTORS
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The Boston Retinal Implant Project
your tax dollars at work
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Retinal Implant Current Design
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Chip and electrode array
Receiving Coil
Transmission Coil
Miniature camera
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Surgery
Electrode Array
Stimulation Experiment
Rizzo et al., 2003 IOVS
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The Future

• Continued development of new paradigm array and
  human clinical trials
• Development of Performance Assessment Paradigms
• Studies in Neuroplasticitywhat will this teach
  us?

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Normal Sensory Perception
Visual
Auditory
Tactile
Merabet et al., Nature Reviews NeuroSci, 2005
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Visual Deprivation
Auditory
Tactile
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Restoring Vision
pattern generated with prosthesis
Visual
Auditory
Tactile
visual percept
?
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True Functional Vision from merging the senses
Visual
Auditory
Tactile
visual percept
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An AnalogyPowered Flight
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(No Transcript)
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Thank youAlvaro Pascual-Leone, MD PhDJoseph
Rizzo, MDDavid Somers, PhDAmir Amedi, PhDPeter
Meijer, PhDHarvard Thorndike GCRCBoston VA
Medical CenterMGH Martinos Neuroimaging Center
BU Medical Neuroimaging Center Carroll Center
for the BlindPerkins School for the Blind