Can Optogenetics Decode Human-Specific Hyperexcitability Circuits?

The persistent failure to control seizures in 30% of epilepsy patients stems from a critical gap: How do human-specific circuit architectures drive pathological hyperexcitability? While optogenetics has revolutionized seizure control in rodents, translation to humans falters due to interspecies divergences in connectivity, oscillatory dynamics, and pharmacoresistance. A closed-loop optogenetic platform was developed using ex vivo human hippocampal tissue to interrogate epileptogenic circuits with cellular specificity and millisecond precision. By restricting K⁺-conducting optogenetic inhibitor (HcKCR1) expression to excitatory neurons via the human-optimized CAMK2A promoter, we can now achieve biomarker-triggered suppression of pharmacologically induced seizures while preserving physiological rhythms. High-density microelectrode arrays reveal human-unique signatures of theta-coherent bursting (4-8 Hz) and propagating wavefronts that resist conventional open-loop neuromodulation. Crucially, closed-loop control remained effective with partial neuronal transduction (10-54%), demonstrating that decoding spatiotemporal hyperactivity patterns, rather than blanket neuronal silencing, holds therapeutic promise for personalized neuromodulation.