Another interesting story about invertebrate brains, in this case the spider:
“Spiders are very smart, that’s why we’re studying them,” says Ronald Hoy, a professor of neurobiology and behavior at Cornell University. “They use visual cues to steer by, and the kind of mazes that they can solve is considered to be pretty impressive for an invertebrate.”
peakmemory 
Truly amazing … If spiders were the size of humans, how big would their brains be in relation to ours?
I don’t know the answer to this. I remember that Spider-Man is supposed to have the proportional strength of a spider, and I did find some information on that claim:
https://answers.yahoo.com/question/index?qid=20070720210557AAb1MCn