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Measuring plasticity using non-invasive brain stimulation--a
potential tool for the study of aging.
Joyce Gomes-Osman, PT, PhD Assistant Professor
Departments of Physical Therapy and Neurology University of Miami Miller School of Medicine
Cognitive Aging Changes in brain
structure + cognitive function
Neuroplasticity
McKnight Registry Cognitive
performance Current Study ?
Experimental models
Humans: On-line assessment
Humans: Imaging
Long-lasting synaptic change (learning/memory, neuroplasticity)
“Repeated activity of specific inputs leads to gradual formation of
assemblies of interacting neurons within restricted neural circuits, which
persists for some time after the cessation of the stimulus.”
Donald Hebb
Long-term potentiation: one paradigm to study neuroplasticity
(Christie et al, 2008)
Stim
Transcranial Magnetic Stimulation
• Electromagnetic Induction of electrical currents
(Bolognini et al, 2010)
Red: direction of magnetic field Green: direction of electrical current
Theta Burst Stimulation- non-invasive plasticity measurement
(Frontiers Synaptic Plasticity 2011; Brain Topography 2011; Eur J Neurosci 2012)
8 s 2 s
200 ms
Bursts of 3 pulses at 50 Hz
600 pulses over 192 s
Following iTBS Baseline
EMG
LTP-like Plasticity
Theta Burst Stimulation- non-invasive plasticity measurement
(Gomes-Osman &Pascual-Leone, unpublished data)
Pilot study suggests iTBS-based plasticity decreases with age
(Modified from Freitas et al, 2011)
Ar
ea o
f Δ in
mot
or e
voke
d po
tent
ial
Age (years)
DM2: r = .45* OHC: r = -.25*
RAVLT Delayed Recall vs. T10 %∆
100
80
60
40
20
0
DM2: r = .59** OHC: r = -.13**
RAVLT Immediate Recall vs. T10 %∆
-100
0 50 100 200 -50 150
100
90
80
70
60
50
40
RAV
LT Im
med
iate
Rec
all (
% c
orre
ct)
%∆ in MEP at T10 %∆ in MEP at T10
RAV
LT D
elay
ed R
ecal
l (%
cor
rect
)
-100
0 50 100 200 -50 150
iTBS-based plasticity correlates with cognitive performance
(Fried & Pascual-Leone, in submission)
Questions
• What are “normal” and “non-normal” values for TMS-based assessment of plasticity?
• Is there a relationship between iTBS-plasticity and cognitive function (neuropsychological evaluation)?
• Does a greater “neuroplasticity reserve” confer any protection from the development of AD? – Responsiveness to training
Experimental Setup
Brain Plasticity Research Registry
McKnight Aging Registry
Participants: Oldest old individuals
Brain Plasticity Research Registry
Screening
iTBS Plasticity
Gait/Postural Control
Exercise Habits
Follow-up
iTBS Plasticity
Gait/Postural Control
Exercise Habits
Acknowledgements: Dr. Kirk-Sanchez Dr. Ralph Sacco Dr. Clinton Wright Maria Carolina Mendoza-Puccini
