L'organisation du réseau est globalement atypique dans l'autisme: une étude de la théorie graphique de la connectivité fonctionnelle intrinsèque

Aperçu: G.M.

En dépit de nombreuses preuves d'anomalies du réseau cérébral dans le "trouble du spectre de l'autisme" (TSA), les résultats ont varié d'une large sous-activité fonctionnelle à une large surconnexion.  Plutôt que de chercher à simplifier trop les hypothèses générales («sous» contre «plus»), L'équipe a testé l'hypothèse d'une distribution de réseau atypique dans les TSA (c'est-à-dire la participation de loci inhabituels dans les réseaux fonctionnels distribués).

Selon l'hypothèse, l'indice Rand (reflétant la façon dont l'organisation du réseau était similaire à un ensemble normatif de réseaux) était significativement plus faible chez les TSA que chez les TD. Cela s'explique par une cohésion et une densité réduites à l'échelle globale, mais une dispersion accrue des réseaux. 

Biol Psychiatry Cogn Neurosci Neuroimaging. 2017 Jan;2(1):66-75. doi: 10.1016/j.bpsc.2016.07.008.

Network organization is globally atypical in autism: A graph theory study of intrinsic functional connectivity

Keown CL^1,2, Datko MC^1,2, Chen CP^1,3, Maximo JO¹, Jahedi A^1,4, Müller RA¹.

Author information

1

Brain Development Imaging Laboratory, Department of Psychology, San Diego State University, San Diego, CA, United States.

2

Department of Cognitive Science, University of California, San Diego, CA.

3

Computational Science Research Center, San Diego State University, San Diego, CA.

4

Department of Mathematics and Statistics, San Diego State University, San Diego, CA, United States.

Abstract

BACKGROUND:

Despite abundant evidence of brain network anomalies in autism spectrum disorder (ASD), findings have varied from broad functional underconnectivity to broad overconnectivity. Rather than pursuing overly simplifying general hypotheses ('under' vs. 'over'), we tested the hypothesis of atypical network distribution in ASD (i.e., participation of unusual loci in distributed functional networks).

METHODS:

We used a selective high-quality data subset from the ABIDE datashare (including 111 ASD and 174 typically developing [TD] participants) and several graph theory metrics. Resting state functional MRI data were preprocessed and analyzed for detection of low-frequency intrinsic signal correlations. Groups were tightly matched for available demographics and head motion.

RESULTS:

As hypothesized, the Rand Index (reflecting how similar network organization was to a normative set of networks) was significantly lower in ASD than TD participants. This was accounted for by globally reduced cohesion and density, but increased dispersion of networks. While differences in hub architecture did not survive correction, rich club connectivity (among the hubs) was increased in the ASD group

CONCLUSIONS:

Our findings support the model of reduced network integration (connectivity with networks) and differentiation (or segregation; based on connectivity outside network boundaries) in ASD. While the findings applied at the global level, they were not equally robust across all networks and in one case (greater cohesion within ventral attention network in ASD) even reversed.

PMID:28944305

PMCID:PMC5607014[Available on 2018-01-01]

DOI:10.1016/j.bpsc.2016.07.008