Neuroimaging and neurochemistry of autism.

Positron emission tomography, single-photon emission tomography, and magnetic resonance spectroscopy (MRS) are powerful tools for the monitoring of diverse neurochemical functions. Neuroimaging studies targeting neurotransmitter systems in autism have provided clues about how differences in development of these systems might lead to new intervention approaches. Direct measurement of diverse neurochemicals with MRS provides unique probes of neuronal integrity in vivo. Future directions include the combination of imaging modalities made possible by advances in software and hardware. Many tracers have not been applied in autism, and new molecules and signaling pathways might be targeted as genes associated with autism are identified.