Neuroscientific evidence is increasingly being introduced in legal contexts, and neurolaw scholarship is correspondingly on the rise. Yet absent from neurolaw research to date are extended examinations of neuroscience in legislative domains. This Article begins to fill that gap with a focus on the illustrative case of neuroscience and juvenile justice in state legislatures. Such examination reveals distinctions between lab neuroscience, lobbyist neuroscience, and legislator neuroscience. As neuroscience narratives are constructed in the policy stream, normative questions arise. Without courtroom evidentiary rules to guide the use of neuroscience in legislatures, these questions are complicated. For instance, to what extent should lobbyists ...