Light-controlled synaptic switch tested in mouse brain

Blue light can interrupt communication at selected synapses and let it return later. Researchers led by Ji Won Um at DGIST, working with Alice Ting's team at Stanford University, developed LATeNT, a molecular tool that temporarily blocks signal transmission between neurons and restores normal signaling within approximately 24 hours after the light is removed.

The switch works by combining a light-sensing protein with tetanus neurotoxin. When exposed to blue light of a specific wavelength, LATeNT cuts VAMP2, a protein required for releasing neurotransmitters—the chemical messages neurons use to communicate. Remove the light, and neurotransmission naturally returns to its original state. That reversibility addresses a limitation of conventional optogenetics, which has mainly controlled a neuron's electrical activity rather than suppressing a chosen synapse for an extended period and then fully restoring it.

In a mouse model, the team used LATeNT to transiently silence signals from specific inhibitory neurons in the hippocampus, a region involved in memory and emotion. The experiments showed that those neurons contribute to brain circuits associated with anxiety-related behavior. LATeNT produced stronger and more sustained inhibition than the conventional optogenetic tools used for comparison.

The same platform was also applied to pancreatic β cells, where light was used to regulate insulin secretion. That broadens the immediate research value beyond neural circuits: the authors say LATeNT could help investigate metabolic and immune disorders and support synthetic-biology genetic circuits. The work was published in Nature Methods.

So what changes in practice? Researchers gain a reversible way to test what a particular synaptic connection does, rather than shutting down an entire neuron and leaving its normal activity altered. The result is still a laboratory research platform tested in cultured neurons, pancreatic cells and mice—not a human therapy; proposed future combinations with gene delivery or drug-control systems remain prospective.