Scientists at Harvard University have uncovered surprising results when studying data analysing the behaviour of zebrafish larvae during feeding.
Advances in imaging technology mean scientists can now visualise communication between cells in the brain and their activity, in some cases even when there is no stimulus, suggesting a behavioural or emotional state of the animal.
The team expected to see peaks of activity in the brain when larvae came into contact with prey, but they observed that some cells were active for many minutes, instead of only seconds, and long before the larvae had actually seen their prey.
These results indicate that there could be an internal brain state that is active throughout this time, suggesting this is a distinct behaviour of the zebrafish larvae and not simply a reaction to their environment.
Similar studies are trying to understand this behaviour in other animals such as fruit flies and mice at the California Institute of Technology, which in turn could help better explain interruptions in human internal brain states seen in some mental health disorders.