Figure 5.

Neural activity score summarizes neural activity for neurotoxicology screening. (a–c) Examples of NAS calculation for all concentrations of three compounds of varying toxicity from EPA compound libraries analyzed. (d–f) Concentration–response curves showing how EC₅₀ was determined for the same three compounds. Grey dotted line indicates 50% of control NAS AUC, used as a threshold for EC₅₀ extrapolation (indicated via red dashed line). Note the lack of extrapolation for aspirin since sufficient effect was not detected. (g) Summary of NAS EC₅₀ values from Frank et al. 2017²² and Shafer et al. 2019²¹. (Left) Total compounds with detected effects (EC₅₀ within tested range). (Inset) Sensitivity comparisons for NAS vs. average individual MEA parameter and cytotoxicity assays for all compounds with detected effects. Higher sensitivity is defined as lower EC₅₀ value.