During the first few years of life, children rapidly incorporate signals from their surrounding enviroment into what will become their behavioral, social and language repertoires. This experience-dependent sculpting of brain circuits occurs during distinct critical periods, and it is during these periods that symptoms of autism spectrum disorders become evident. Many of these symptoms indicate a disruption in sensory processing.

All sensory information, with the exception of olfactory information, travels first to a brain structure called the thalamus, where it is processed and integrated before it is relayed to the cerebral cortex. Chinfei Chen and Michela Fagiolini’s laboratories at Children’s Hospital Boston aim to test the hypothesis that communication between the thalamus and cortex is commonly disrupted in autism.

The researchers plan to use the visual system as an experimental model because it is the best-understood mammalian sensory system. Using a combination of electrophysiology and behavioral testing, they plan to study the development and plasticity of neuronal networks in the thalamus and cortex of a variety of mouse models of autism. They also plan to examine the response of these networks to changes in sensory experi­ence, as well as to localized damage to the circuitry.

This multi-level systems approach may elucidate whether disruption of feed-forward and feedback interac­tions between local circuits within a sensory system is a common feature of autism spectrum disorders. Understanding the interdependence of critical period plasticity of different structures in the brain is key to developing new strategies to recover brain function in these disorders.