Table 3. Environmental-induced ASD animal models.

Environmental factors	Brain impacts		Clinical relevancea													References
			Typical symptoms							Animal performanceb
			①	②	③	④	⑤			①	②	③	④	⑤
a: ①: Social communication disorders; ②: Repetitive/stereotyped behaviors; ③: Narrow interests; ④: Impaired linguistics; ⑤: Intellectual disability. +: Positive, –: Negative; NT: Not tested. b: M: Monkey; R: Rodents; F: Fish; I: Invertebrates.
VPA	Affects expression of BDFN mRNA in brain tissue		+	+	+	+	+		R	+	+	+	–	+		Almeida et al., 2014; Banerjee et al., 2014; Kim et al., 2014a; Reynolds et al., 2021
									F	+	+	+	–	+
PPA	Reactive astrocyte keratinization of brain tissue; microglia are activated; oxidative stress markers rise; glutathione declines		NT	NT	NT	NT	NT		R	+	+	+	–	+		El-Ansary et al., 2012; Foley et al., 2015; MacFabe et al., 2011; Shultz et al., 2009
BPA	Changes in number of neurons and glia in the medial prefrontal lobe		+	+	+	+	+		R	+	+	+	–	+		Braniste et al., 2010; Sadowski et al., 2014; Vermeer et al., 2014; Xu et al., 2015
Sevoflurane	Increases the number of apoptotic cells in brain; inhibits the axon development of hippocampal neurons		NT	NT	NT	NT	NT		R	+	+	+	–	+		Chen et al., 2020; Jin et al., 2020
MIA	Abnormal increase of offspring’s brain volume		+	+	+	+	+		M	+	+	+	–	+		Bauman et al., 2013; Braunschweig et al., 2012; Breach et al., 2021
									R	+	+	+	–	+
BDV	Abnormal hippocampal and cerebellar development		+	+	+	+	+		R	+	+	+	–	+		Pletnikov et al., 2002; Taieb et al., 2001
GM	Regulation of neuroactive metabolites		+	+	+	+	+		M	+	+	+	–	+		Sharon et al., 2019
									R	+	+	+	–	+
									F	+	+	+	–	+
									I	+	+	+	–	+
RCS	Changes in neurotransmitter and corticosterone levels		NT	NT	NT	NT	NT		R	+	+	+	–	+		Hata et al., 1987; Namimatsu et al., 1992