As a tasty paramecium flits around the head of a hungry fish, nerve cells in the fish’s brain track the prey and flicker in response. This reaction, caught in real time by scientists, helps illuminate how brains perceive the outside world.
To catch a glimpse inside a larval zebra fish’s brain as it stalks a paramecium, Koichi Kawakami of the National Institute of Genetics in Mishima, Japan, and colleagues genetically engineered the fish so its neurons would glow when excited.
As prey swam near the fish, neurons in the front part of a brain region called the optic tectum became active, scientists report in the February 18 Current Biology. These cells probably send messages to the eyes and swimming machinery, helping to kick off the hunt.
Nerve cells in a zebra fish’s brain fire off signals (pink) as its prey, a paramecium, darts around nearby. Credit: Current Biology, A. Muto et al/Current Biology 2013