MIT engineers reported on Aug. 14, 2026, in Nature Methods a light sheet microscope adapted for fast, high-volume imaging that tracked electrical activity across the brain of the experimental model zebrafish on a millisecond scale. The team increased camera acquisition speed and scanning speed using remote refocusing, scanning the entire larval zebrafish brain 200 times per second, or once every five milliseconds.

In tests, neurons were engineered to express the voltage indicator Positron2-Kv. Although researchers had hoped the indicator would reach every neuron, about one quarter showed acceptable signals, which the study says was enough to observe activity patterns. The work captured single voltage spikes and rapid bursts, activity in the optic tectum following ultraviolet light, and stimulus-independent sequences in the cerebellum and hindbrain.

The researchers hope to image a larger percentage of neurons and improve speed and resolution, and are working to extend the technique to other experimental models, including mice. Ed Boyden, the senior author, said the method could help study how neurons function together as a network. The research was funded in part by the National Institutes of Health and the BRAIN Initiative.