Outside of chordates, the brain is very rare. All plants, all fungi, all arthropods, all unicellular organisms do not have a brain. Unless octopuses have brains. For the rest, at best, you can talk about a ganglion – a nerve node in the head.
There are many such examples. For example, the mold polycephalum, would seem to be a simple organism, but in a scientific experiment with a maze, it orders subject logic! Or take the classification of worms, that is, there is no brain as such, but there are other mechanisms that affect the motor skills of actions.
Outside of chordates, the brain is very rare. All plants, all fungi, all arthropods, all unicellular organisms do not have a brain. Unless octopuses have brains. For the rest, at best, you can talk about a ganglion – a nerve node in the head.
There are many such examples. For example, the mold polycephalum, would seem to be a simple organism, but in a scientific experiment with a maze, it orders subject logic! Or take the classification of worms, that is, there is no brain as such, but there are other mechanisms that affect the motor skills of actions.