Transient Early Postnatal Neuronal Hyperexcitation Results in Lasting Social Preference Deficits

Perturbations during critical periods of neurodevelopment are implicated in the etiology of autism spectrum disorder (ASD), a condition marked by considerable heterogeneity and prevalent comorbidities. One such comorbidity is epilepsy, with approximately 30% of children with ASD experiencing seizures and a similar proportion of children with epilepsy displaying ASD-like symptoms. Both conditions have been associated with disruptions in the brain's excitation-to-inhibition (E/I) balance. Although early-life seizures in rodents have been linked to social impairments, direct causal evidence connecting E/I imbalance, interneuron development, and social behavior remains limited. To address this gap, we induced transient, brain-wide hyperexcitation in neonatal mice using pentylenetetrazol (PTZ), a GABA_A receptor antagonist. We administered both convulsive and subconvulsive doses and assessed long-term effects on social behavior, cortical E/I balance, and parvalbumin (PV) interneuron development. PTZ-treated groups displayed impaired social preference as measured in the 3-chamber test and increased PV interneuron density within the medial prefrontal cortex. These findings highlight a critical developmental window during which E/I imbalance leads to social deficits characteristic of ASD and epilepsy. They also reveal dose-dependent neurobiological changes, underscoring the importance of early-life neural activity in shaping social circuitry.