What invertebrates has cerebral ganglia that are organized into a brain?

Cephalopods, such as octopuses and squids, are invertebrates that possess cerebral ganglia organized into a brain. This complex nervous system allows them to exhibit advanced behaviors, problem-solving skills, and learning abilities. Additionally, some species of annelids, like certain polychaetes, also show a degree of brain-like structures in their ganglia, though they are less complex than those found in cephalopods.