Measuring plasticity using non - invasive brain ...

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(Gomes-Osman &Pascual-Leone, unpublished data)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

[email protected]