Researchers have uncovered critical insights into how autism spectrum disorders (ASD) may develop at early stages of brain formation. Using mouse models, the team discovered that environmental factors causing autism-like symptoms are linked to early changes in neurotransmitter activity in the brain. Specifically, they observed that a temporary switch from the inhibitory neurotransmitter GABA to the excitatory neurotransmitter glutamate in neonatal mice could lead to the development of ASD-like behaviors, such as repetitive actions and reduced social interaction, later in life.