Via Gizmodo, you can now truly see someone thinking:

A team of Japanese researchers has captured, for the first time ever, a movie which shows how thoughts form in the brain. OK, so it’s a thought forming in the brain of a zebrafish. But this is a fundamental leap forward in our understanding of how brains work.

The researchers used a new technique to record the footage: a super-sensitive fluorescent probe that detects neuron activity. We see neurons glowing when they’re active—and the cascade of light you see in this video is the neuronal response of a zebrafish responding to the presence of its prey.