C. ASSAIANTE (1), F. CIGNETTI (1), A. FONTAN (1), B. NAZARIAN (2), J.L. ANTON (2), M. VAUGOYEAU (1)

La construction du schéma corporel chez l'enfant et l'adolescent

(1) Aix-Marseille Université, CNRS, LNC UMR 7291, Marseille, France

(2) Aix-Marseille Université, CNRS, INT UMR 7289, Centre IRM Fonctionnelle Cérébrale, Marseille, France

Ø Pour percevoir et agir dans son environnement, le corps, lescaractéristiques de l’action et leurs interactions sontreprésentés dans le cerveau.

Ø Cette représentation interne des segments corporels enmouvement a été conceptualisée sous le terme de schémacorporel (Head and Holmes, 1911; Maravita et al, 2003;Dijkerman and de Haan, 2007).

Ø La fonction principale du schéma corporel est de permettrel’exécution de ses propres actions, mais le schéma corporelcontribue également à comprendre une action exécutée par unautre et ainsi à comprendre les interactions sociales grâce aulien fonctionnel entre la perception et l’action (Rizzzolatti et al,2001; 2002; Miall, 2003; Centelles et al, 2011).

Le schéma corporel

3

Paillard 1982 : « identified body and situated body »

Lopez et al., 2012 :Contribution of vestibular

informations

« identified body » à visual informations« situated body » à proprioceptive informations

body schema is dependant on ongoing sensory inputs (proprioceptive, visual and vestibular), operates largely unconsciously and is concerned with body movements.

body schema from a neurosensory approach

Proske and Gandevia, 2012The proprioceptive senses

DEVELOPMENT OF PROPRIOCEPTIVE ABILITY

Goble et al. (2005) Hum Movement Sci

DEVELOPMENT OF PROPRIOCEPTIVE ABILITY

Goble et al. (2005) Hum Movement Sci Yeh, Holst-Wolf, Konczak (2014) Poster Neuroscience,

Washington

Proprioceptive acuity improves with age, as evaluated both

from absolute errors and trial-to-trial error variability

Vaugoyeau et al. (2008) Gait PostureMallau et al. (2010) PLoS One

DEVELOPMENT OF PROPRIOCEPTIVE ABILITY

5/6 7/10 11/13 14/15

5/6 7/10 11/13 14/15 5/6 7/10 11/13 14/15

5/6 7/10 11/13 14/15 Adults5/6 7/10 11/13 14/15

Proprioceptive integration for postural control slowly improves

during childhood and adolescence

Behavioral study

1/ Quantify postural adjustments evoked through tendon vibration in standing position

Analysis of the displacement of the center of pressure and of the trunk rotation

2/ Quantify the illusory movement induced by vibration in sitting position

Analysis of the displacement of the right finger index movement that had to match illusory movement of the feet

ADU [20-40 y]N=12; 6♀-6♂

ADO [14-18 y]N=13; 5♀-8♂

preADO [11-14 y[N=14; 8♀-6♂

*Cignetti et al. 2013J Mot Learn Dev

Behavioral study

Ü Exaggerated responses in ADOÜ Proprioceptive ability continue to improve throughout adolescence

*Cignetti et al. 2013J Mot Learn Dev

Goble et al. (2011) J NeurosciGoble et al. (2012) Hum Brain Mapp

CENTRAL PROPRIOCEPTIVE PROCESSING

EXPERIMENTAL PROTOCOL

Vibration of TA tendonleft, right, 30 Hz, 100 Hz

Pre-scanningScanning (×5)

~ 5min / session (113 scans)

rand.

12sISI12s

…

12s12sISI

RE

ST

RE

ST

Illusions ?

n = 18 18 18 18

1113

1418

2540Age: 7

10

METHODS Standard GLM

Fitti

ng(M

L es

timat

or)

fMRI time series(motion correction, spatial normalization, smoothing)

Voxel timecourse

PROPRIOCEPTIVE NETWORK IN ADULTSp < 0.001 uncorr. | p<0.05 FWE-corr.

Cignetti et al. 2014 Hum Brain Mapp

p < 0.001 uncorr.

Right stim.

Left stim.

Right-hemisphere dominance

IPLIFG

DEVELOPMENTAL CHANGES

Work in progress

§ Proprioceptive network looks already mature in pre-adolescents using a standard GLM approach

preADO

ADO

ADU

IPL

IFG

Right-hemisphere dominance

METHODS

Beta Series GLM

Each predictor was replaced with a series of predictorsi.e. after fitting, a series of betas

Correlated the seed beta series with the beta series at every other voxel of the brain

Rissman et al. 2004 NeuroImage

DEVELOPMENTAL CHANGES IN CONNECTIVITY MAPS

Work in progress

§ Shift in pattern of functional connectivity from diffuse to more focal, or a fine-tuning of the proprioceptive connectivity network.

preADO ADO ADU

DEVELOPMENTAL CHANGES

Work in progress

§ Proprioceptive network looks already mature in pre-adolescents using a standard GLM approach

§ Initial over-connectivity followed by a weakening coupling with several brain regions, that is a kind of pruning at the system level.

preADO100Hz

preADO30Hz

ADO100Hz

ADO30Hz

ADU100Hz

ADU30Hz

DEVELOPMENTAL CHANGES

Work in progress

PreADO

ADO

ADU

Univ.

Beta

Shared

DEVELOPMENTAL VARIABILITY

Work in progress

What it means for a region to be correlated with the seed while failing to show significant univariate activity?

Firing of the neurons may not be enough to drive the BOLD signal above threshold on average, due to poor neural activity on some trials.

Larger trial-to-trial variability in the amount of proprioceptive-induced neural activity in pre-adolescents and adolescents, i.e. a suboptimal network functioning.

Neuroimaging studyCHILDREN [7-10 y]N=18; 11♀-7♂

DEVELOPMENTAL CHANGES IN ACTIVATION MAPS

The proprioceptive network looks already mature in children using a standard GLM approach.

CHILDREN VERSUS ADULTS

Ü Significant larger extent of activation in children compared to ADU

Ü Significant stronger SMA activity in children compared to ADU

IPL

IFG

Right-hemisphere dominance

Ü No Right hemispheric dominance in children

Ü Right hemispheric dominance in adolescents and adults

WORK STILL IN PROGRESSü18 Children already scanned; Slightly increase

the sample size.

üComparative analysis between children and adolescents and adults- fMRI (activation maps)- fMRI (connectivity maps)- DTI (white matter tracts)

üCorrelation between fMRI and DTI data and behavioral indices about proprioceptive acuity and postural control

Position matching tasks and postural task