Autism may emerge from a general unreliability of neuronal responses in the brain's cortex, rather than from a deficiency in one particular brain area or circuit.

Ilan Dinstein at Carnegie Mellon University in Pittsburgh, Pennsylvania, and his colleagues studied 14 people with autism and 14 people without the disorder. The researchers used functional magnetic resonance imaging to monitor cortical responsiveness as they stimulated the participants' sight, hearing and touch in dozens of trials.

Responses in the visual, auditory and somatosensory areas of the cortex all varied much more between trials for the volunteers with autism than for the controls. The authors propose that this may reflect inappropriate development of neuronal connections, or synapses, in the autistic brain.

Neuron 75, 981–991 (2012)