That’s what Science Daily says scientists have been doing when they hook up a probe precise enough to detect a single idea begin to form in a specific brain cell:
“Our work is the first to show brain activities in real time in an intact animal during that animal’s natural behavior,” said Koichi Kawakami of Japan’s National Institute of Genetics. “We can make the invisible visible; that’s what is most important.”
The technical breakthrough included the development of a very sensitive fluorescent probe to detect neuronal activity. Kawakami, along with Junichi Nakai of Saitama University and their colleagues, also devised a genetic method for inserting that probe right into the neurons of interest. The two-part approach allowed the researchers to detect neuronal activity at single-cell resolution in the zebrafish brain.