Altered neural connectivity in excitatory and inhibitory cortical circuits in autism

Traduction partielle: G.M.

Front Hum Neurosci. 2013 Sep 27;7:609. doi: 10.3389/fnhum.2013.00609.

Connectivité neuronale altérée dans les circuits corticaux excitateurs et inhibiteurs dans l'autisme

Zikopoulos B, Barbas H.

Source

Neural Systems Laboratory, Department of Health Sciences, Boston University Boston, MA, USA.

Abstract

Converging evidence from diverse studies suggests that atypical brain connectivity in autism affects in distinct ways short- and long-range cortical pathways, disrupting neural communication and the balance of excitation and inhibition. This hypothesis is based mostly on functional non-invasive studies that show atypical synchronization and connectivity patterns between cortical areas in children and adults with autism. Indirect methods to study the course and integrity of major brain pathways at low resolution show changes in fractional anisotropy (FA) or diffusivity of the white matter in autism. Findings in post-mortem brains of adults with autism provide evidence of changes in the fine structure of axons below prefrontal cortices, which communicate over short- or long-range pathways with other cortices and subcortical structures. Here we focus on evidence of cellular and axon features that likely underlie the changes in short- and long-range communication in autism. We review recent findings of changes in the shape, thickness, and volume of brain areas, cytoarchitecture, neuronal morphology, cellular elements, and structural and neurochemical features of individual axons in the white matter, where pathology is evident even in gross images. 

Nous rapportons les caractéristiques cellulaires et moléculaires pour des études d'imagerie et de génétique qui mettent en évidence une variété de polymorphismes et les facteurs épigénétiques qui affectent principalement la croissance des neurites et la formation des synapses et la fonction de l'autisme. 
Nous rapportons les résultats préliminaires de l'évolution de l'autisme dans le rapport de types distincts de neurones inhibiteurs dans le cortex préfrontal, appelés à façonner la dynamique des réseaux et l'équilibre entre l'excitation et l'inhibition.
 

Finally we present a model that synthesizes diverse findings by relating them to developmental events, with a goal to identify common processes that perturb development in autism and affect neural communication, reflected in altered patterns of attention, social interactions, and language.

PMID: 24098278