The current trends and future prospect of neural activity measurement by genetically-encoded voltage indicators

Genetically-Encoded Voltage Indicators (GEVIs) draw neuroscientist's attention since it enables to simultaneously monitor direct electrical activity from lots of neurons, and which is not achievable by using electrodes. However many GEVIs reported so far often confuse users. Actually since each GEVIs has pros and cons, we have to carefully select GEVIs which is the most suitable for one's experiments according to the accurate information. Here, we describe the trend of GEVIs from ion channel based GEVIs reported as prototypes in the early stage to current rhodopsin-fluorescent protein based GEVIs. Also we note the feature of representative GEVIs and which GEVIs should be used for one's experiments.