The Mousing Problem: Why Whole-Brain Emulation Makes AI Suffering Measurable, and What Existing Neuroscience Already Tells Us About It

The March 2026 demonstration of a closed-loop whole-brain emulation of the Drosophila melanogaster brain by Eon Systems PBC marks a qualitative threshold in the ethics of digital minds. For the first time, a complete biological connectome runs in silicon and drives a physically simulated body. With mouse and human brain emulation declared as the next targets, this paper argues that the question of digital suffering moves from philosophy to empirical measurement.
Three existing transgenic mouse experiments — the Doogie mouse (Tang et al., 1999), the PDE4B mouse (McGirr et al., 2015), and the ARHGAP11B mouse (Xing et al., 2021) — establish that the pathway to intelligence, not intelligence itself, determines the emotional and suffering profile of the resulting brain. These findings are connected here for the first time to whole-brain emulation ethics and provisionally mapped to AI training architectures.
The paper introduces "Mousing" as a new moral category: the act of creating a suffering-capable substrate instrumentally, with no responsibility for the nature of its existence. No existing legal or ethical framework currently covers this gap.