The brain of most animals is encased in a thick, protective skull. For this reason, neuroscientists have struggled to view activity at the level of individual neurons in real time. A recent experiment in transgenic zebrafish, however, has allowed researchers to do just that, with illuminating results.
Dr. Misha Ahrens and his colleagues at Harvard University paralyzed a larval zebrafish and subjected it to virtual inputs that mimic the visual input typically received by the passage of water over the eyes during swimming. In a sense, the fish was tricked into thinking it was swimming, and as such responded by producing motor commands in its cortex as it navigated through what could be termed The Fish Matrix.
Experimenters were able to use two-photon calcium imaging to record a highly detailed video of the zebrafish’s brain through its relatively transparent skull as it orchestrated motor commands, revealing the dynamic neuronal network activity in motor regions of the cortex for the first time.
This promising technique can potentially reveal the networked neuronal activity of many other brain processes in the zebrafish, and could allow us to develop better theories of network dynamics.