Excitatory/Inhibitory Balance and Circuit Homeostasis in Autism Spectrum Disorders

Abstract

Autism spectrum disorders (ASDs) and related neurological disorders are associated with mutations in many genes affecting the ratio between neuronal excitation and inhibition. However, understanding the impact of these mutations on network activity is complicated by the plasticity of these networks, making it difficult in many cases to separate initial deficits from homeostatic compensation. Here we explore the contrasting evidence for primary defects in inhibition or excitation in ASDs and attempt to integrate the findings in terms of the brain's ability to maintain functional homeostasis. This Review addresses the current debate surrounding the primary neurological deficit underlying Autism spectrum disorders. Nelson and Valakh examine evidence for primary defects in inhibition or excitation in forebrain circuits and integrate the findings with network requirements for functional homeostasis.