One of the biggest advances in recording from neurons has been the development of genetically-encoded calcium indicators. These allow neuroscientists to record the activity of large numbers of neurons belonging to a specific subclass. Be they fast-spiking interneurons in cortex or single, identified neurons in worms and flies, genetic encoding of calcium indicators has brought a lot to the field.
Obviously, calcium is just an indirect measure of what most neuroscientists really care about: voltage. We want to see the spikes. A lot of work has been put into making genetically-encoded voltage indicators, though the signal-to-noise has always been a problem. That is why I was so excited to see this paper from Mark Schnitzer’s lab:
I believe they are calling this voltage indicator Ace. It looks pretty good, but as they say time will tell.
The chatter is that it bleaches quickly (usable on the order of a minute) and still has low signal to noise – look at the scale bar ~1% above. I have also heard there may be lots of photodamage. But, hey, those are spikes.