Optical Electrophysiology in Neuronal Systems

Optical electrophysiology harnesses fluorescent sensors to visualise membrane potential changes in neurons with high spatial and temporal resolution. Central to this approach are genetically encoded voltage indicators (GEVIs) and specialised voltage-sensitive dyes that transduce electrical events into optical signals. One-photon widefield techniques allow mesoscopic imaging of large cortical networks in awake animals, while two-photon microscopy affords deep, subcellular resolution in ex vivo and in vivo preparations. Recent advances have focused on enhancing brightness, kinetics, sensitivity and photostability, overcoming limitations in signal-to-noise ratio and artefacts from haemodynamics and motion. Combined with targeted gene delivery and high-speed microscopes, these tools enable single-trial detection of action potentials, mapping of subthreshold dynamics and monitoring of circuit-level computations. The global significance spans fundamental research into neural coding and plasticity, drug screening for neurotherapeutics and potential clinical translation for non-invasive diagnostics in neurological disorders.

Research from Nature Portfolio

Recent studies have evolved voltage indicators for widefield one-photon imaging, culminating in a green-emitting sensor with rapid kinetics and enhanced photostability. A robust screening platform directed multiple rounds of evolution to yield a variant that expresses broadly in neonatal mouse cortex, corrects for haemodynamic artefacts and enables stable, pan-cortical voltage imaging. Single-trial detection of gamma-frequency whisker and visual stimulation demonstrated the utility of this indicator for studying high-frequency brain dynamics in awake subjects. In parallel, a fluorescent voltage sensor has been applied to the mammalian olfactory bulb in vivo, resolving fast, glomerulus-specific responses to odour stimuli. Compared with calcium sensors, this voltage reporter exhibited superior temporal fidelity and clearer demarcation of subthreshold events, establishing a framework for optical electrophysiology of sensory circuits.

Optical Electrophysiology in Neuronal Systems publication trend

The graph below shows the total number of articles in optical electrophysiology in neuronal systems across all publications each year (not limited to Nature Index journals).

Technical terms

Genetically encoded voltage indicator (GEVI): A fluorescent protein-based sensor that changes optical properties in response to membrane potential variations.

One-photon (widefield) imaging: An optical technique using single-photon excitation to capture mesoscale voltage signals over large neural populations.

Two-photon microscopy: A nonlinear imaging modality employing simultaneous absorption of two photons for deep-tissue, high-resolution voltage measurements.

Photostability: The resistance of a fluorescent indicator to photobleaching under prolonged illumination, crucial for extended recordings.

Sensitivity: The magnitude of fluorescence change per unit membrane potential, determining the detectability of voltage events.

References

1. Widefield imaging of rapid pan-cortical voltage dynamics with an indicator evolved for one-photon microscopy. Nature Communications (2023).
2. An Ultrasensitive Genetically Encoded Voltage Indicator Uncovers the Electrical Activity of Non‐Excitable Cells. Advanced Science (2024).
3. Fast two-photon imaging of subcellular voltage dynamics in neuronal tissue with genetically encoded indicators. eLife (2017).
4. Comparative Evaluation of Genetically Encoded Voltage Indicators. Cell Reports (2019).