Developmental Disturbances in Animal Models of Autism Spectrum Disorder

Although the early signs of autism spectrum disorder (ASD) are widely studied, the significant ambiguity and heterogeneity in symptoms require the comparison of available models, approaches, and the search for common denominators and key indicators. Early ASD symptoms in animal models include impaired somatic development (e.g., delayed eye opening), alterations in primitive motor reflexes, disrupted sensory function as well as communication deficits, such as reduced ultrasonic vocalization. This review aims to summarize early ASD-related symptoms based on studies involving transgenic or neurotoxic rodent models (postnatal days 1-21) and to compare these with human resemblance. The key brain areas (subventricular zone, cortex, hippocampus, cerebellum, etc.) as well as relevant neurotransmitter systems (GABA-glutamate imbalance, developmental GABA shift, serotonin, dopamine, oxytocin [OT], etc.) were identified as potential targets for intervention. OT, although a promising candidate, exemplifies the translational challenges inherent in ASD research. Therefore, it is recommended to monitor a wide range of behavioral signs simultaneously and employ diverse models (e.g., genetic, developmental, environmental, or combination) in preclinical studies to more accurately reflect the complexity of the disorder.