It has become pretty common to see someone, after a neuroscience talk, ask, “Interesting – but have you tried doing this with optogenetics?” As if this technique to precisely activate neurons was something that was trivial to implement. It’s not, obviously, it’s quite expensive and hard (for many systems). Otherwise everyone would be doing it already! Who wouldn’t want to turn neurons on and off at will?
Florian Engert, who imaged all the neurons in the zebrafish brain, used this picture at the end of his talk at CSHL Synapses last year when asking for suggestions on experiments.
[via Cian O’Donnell]
neuroecology 
About as fun for me as, “Have you recorded in vivo?”