Measuring the transduction of electrical signals within neurons is a key capability in neuroscience. Fluorescent voltage sensitive dyes (VSDs) were early tools that complemented classical electrophysiology by enabling the optical recording of membrane potential changes from many cells simultaneously. Recent advances in the VSD field have led to bright and highly sensitive sensors that can be targeted to the desired cell populations in live brain tissue. Despite this progress, recently, protein-based genetically encoded voltage indicators (GEVIs) have become the go-to tools for targeted voltage imaging in complex environments. In this Perspective, we summarize progress in developing targetable VSDs, discuss areas where these synthetic sensors are or could become relevant, and outline hurdles that need to be overcome to promote the routine use of targetable VSDs in neuroscience research.

Department of Chemistry Columbia University New York New York 10027 United States

Department of Chemistry Faculty of Science Masaryk University Kamenice 5 625 00 Brno Czech Republic

Department of Molecular Therapeutics New York State Psychiatric Institute New York New York 10032 United States

Departments of Neurology Psychiatry and Pharmacology Columbia University Irving Medical Center New York New York 10032 United States

Laboratory of Organic Chemistry ETH Zürich D CHAB Vladimir Prelog Weg 3 8093 Zürich Switzerland

The Zuckerman Mind Brain Behavior Institute Columbia University New York New York 10027 United States

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