Y P O C T O N - - PowerPoint PPT Presentation

• Lorella Battelli, PhD

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• TMS over M1
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Plasticity over 1 session:

• MEP amplitude after tRNS over M1

Terney et al., Journal of Neuroscience, 2008

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a-tDCS

• Active Stimulation

20 minutes @1mA anode EVA(OZ), cathode (CZ)

• Sham Stimulation

hf-tRNS

• Active Stimulation

20 minutes @1mA Bilateral EVA (O2, O1)

• Sham Stimulation

n=12 n=12

Measuring Cortical excitability

Florian Heprich Federica Contò

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Phosphene threshold

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• tRNS

tDCS Sham

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Herpich et al., in prep

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Terney et al., 2008 tRNS = 1 mA – 20 min – bilateral stimulation tRNS = 1 mA – 10 min – unilateral stimulation

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Perceptual Learning

Process by which training leads to improvement in abilities to detect, discriminate and identify sensory stimuli

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Single cell recordings revealed that visual experience modifies neuronal connections in early life.

Wiesel and Hubel, 1963

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• Traditionally, brain plasticity has been thought to occur only during

infancy and early development

• Although plasticity effects are strongest during childhood, the last

two decades of research demonstrated that the adult brain is plastic

Conclusions Conclusions

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Coherent Motion Detection in Noise

Post Training

15% 50% 100%

Weak Signal Moderate Signal Strong Signal

Performance Signal Strength

Pre Training Threshold 0% 100%

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Time

Learning Threshold Simple Sensory Input

Stimulus Presentation

Efficacy

Optimization of Sensory Input Attention Reinforcement (Reward - Punishment)

Non-Invasive Brain Stimulation

Conclusions

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Anodal

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• Visuo-perceptual functions can be trained both in healthy adults (Hang et al.,

2014) and in the neurological population (Huxlin et al., 2009; Das et al., 2014)

• Can we use tRNS to boost PL processes to improve visual function in healthy

subjects? (Miniussi et al., 2011)

• Can we use tRNS to boost PL in stroke patients?

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Pre-Training Baseline Pre-Training Baseline 6 Months 6 Months Follow Up Follow Up

N = 45 N = 45 20 Mins.

0 Mins. @ 1mA. @ 1mA.

Fixation

500 ms

tES ES

1000 ms

Florian Heprich

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Stimulation Protocol

a-tDCS a-tDCS tRNS tRNS

Parietal Parietal tRNS tRNS

Sham Sham Behavioral Behavioral

n = 9 n = 9 n = 9 n = 9 n = 9

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10 20 30 40 50 60 70 1 2 4 6 8 10 3 5 7 9 Session Percent improvement a-tDCS Control tRNS

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20 40 60 a-tDCS Control tRNS Post-test 6-month follow-up Amount of learning

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Can tES promote recovery in stroke patients?

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• Damage to V1 in one hemisphere
• Blindness in the opposite

hemifield

• Spontaneous recovery limited to

the first weeks

OS/OD

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• 10

10 20

• Deg. visual angle
• 30
• 20
• 10

10 20 30

• Deg. visual angle

Hemianopic patients

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• No established validated clinical therapies exist for the

restoration of visual field deficits

• But the CB retain residual visual processing abilities

(“Blindsight”, Weiskrantz 1974)

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• Huxlin et al., Journal of Neuroscience, 2009
• Stroke patients with V1 damage
• Trained on global direction

discrimination in cortically blind field

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Huxlin et al., Journal of Neuroscience, 2009

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Pre-Training Baseline Baseline Visual Perimetry

Fixation

1000 ms

Procedure

Visual Perimetry Visual Perimetry

500 ms s

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tRNS Sham

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R2 =.601 R2 =.057

Introduction

Neuroplasticity Materials & Methods Experiments Results Materials & Methods Experiment Results Results Experiments Materials & Methods Perceptual Learning NIBS

Conclusions

r =.23 r =.78

tRNS Sham

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tRNS

Visual Perimetry

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Sham

Visual Perimetry

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• Plasticity over multiple sessions:
• Perceptual learning during tRNS
• ver Parietal Cortex

Cappelletti et al., Journal of Neuroscience, 2013

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• Can we promote learning with tRNS and make it more

efficient? (Cappelletti et al., 2013)

• Short-training paradigm?

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Research report

Functional connectivity of parietal cortex during temporal selective attention

Sarah C. Tyler a,b,*, Samhita Dasgupta a, Sara Agosta b, Lorella Battelli b,c and Emily D. Grossman a

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The ‘When network’

• Temporal Attention: ability to perceive the
• rder and structure of events
• Control of temporal attention, the ‘When

Network’ Crucial role of the Parietal lobe

Hypothesis tRNS modulates parietal cortical activity and consequently improves temporal attention

(Battelli et al., 2007; Tyler et al., 2015)

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• Federica Contò

Sarah Tyler

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Behav hMT+ Parietal Sham

Tyler et al., JoCN, in press 1 Session Blocks

Average performance Improvement by condition

Behavioral Improvement in One Session

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Dual-task Training

Optimize Training + Stimulation

• Extend the effect in time

multi-session stimulation

• Efficiency of training paradigm double-training (Szpiro et al.,

2014)

Neurophysiological effect

• Detecting changes in functional connectivity
• Is the effect local or wide-spread across the attention network?

Grace Edwards Federica Contò Sarah Tyler

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Orientation Discrimination

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Time 1000 ms

Time 1000 ms

+ +

• SOAs

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Temporal Order Judgment

Training on two tasks

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Experimental Procedure

Dual-task Pre-Test Dual-task Post-Test Dual-task training + tRNS MRI Stimulation MRI

t

Multi-Session Between Subjects Design

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Task Design

Orientation Discrimination (OD) Temporal Order Judgment (TOJ) Conditions: Parietal (N = 10) hMT+ (N = 10) Sham (N = 10)

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10 20 30 40 50 60 70 80 90 Day 1 Day 6

Percent Correct

hMT (n=10) Sham (n=10) Parietal (n=10)

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Orientation Discrimination

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Functional Connectivity

Computed FC between these nodes of the attentional network

Individual ROIs

R,L FEF R,L IPS RL, TPJ R,L hMT

FEF MT IPS TPJ F T IPS TPJ PS F

FEF IPS TPJ hMT

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FEF IPS TPJ hMT

Day 6 vs Day 1

Parietal difference between session 1 and session 2

IPSR IPSL hMTR hMTL FEFR FEFL TPJR TPJL IPSR IPSL hMTR hMTL FEFR FEFL TPJR TPJL

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• 0.5

0.5 1

hMT difference between session 1 and session 2

IPSR IPSL hMTR hMTL FEFR FEFL TPJR TPJL IPSR IPSL hMTR hMTL FEFR FEFL TPJR TPJL

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• 0.5

0.5 1

Parietal Day6 vs Day1 hMT Day6 vs Day1

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Transcranial Direct Current Stimulation Facilitates Associative Learning and Alters Functional Connectivity in the Primate Brain

Matthew R. Krause,1 Theodoros P. Zanos,2 Bennett A. Csorba,1 Praveen K. Pilly,3,5,* Jaehoon Choe,3 Matthew E. Phillips,3 Abhishek Datta,4 and Christopher C. Pack1,*

Current Biology

Article

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Conclusions

• tRNS over the Parietal Lobe promotes and speeds up learning

within few training sessions

Neural processes sufficiently stimulated while in a sensitized state Double training coupled with tRNS can maximize learning

• tRNS may be changing functional connectivity among critical

nodes of the attention networks

• Potential clinical applications

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