Andrej Karpathy observes that the hippocampus and amygdala, which are involved in emotions and instincts, are not yet replicated in current models.
where's the hippocampus? Not obvious what that would be. Some parts are probably not important. Maybe the cerebellum is not important to cognition, its thoughts, so maybe we can skip some of it. But I still think there's, for example, the amygdala, all the emotions and instincts.