There is a lot of overlap between AI and Neuroscience, especially among older researchers. For example Karpathy's PhD supervisor, Fei-Fei Li, researched vision in cat brains before working on computer vision, Demis Hassabis did his PhD in Computational Neuroscience, Geoff Hinton studied Psychology etc... There's even the Reinforcement Learning and Decision Making conference (RLDM - very cool!), which pairs Reinforcement Learning with neuro research and brings together people from both disciplines.

I suspect the average AI researcher knows much more about the brain than typical CS students, even if they may not have sufficient background to conduct research.

Fair enough, I guess its a bit different nowadays since the background is usually a PhD in compsci