You said it cannot fully function. I want to know why you say this.
Oh.
One, what Pixy suggested, and two, because furthermore many instructions are meaningless without an OS.
For example there are instructions dealing with security layers in memory, I.E. only the OS gets to access certain address spaces, etc. Without an OS, those instructions aren't ever used.
The analogy with emotion-attention is simple: Just because you have something like the limbic system that apparently functions without a neocortex does not imply that the full functionality of the limbic system is available without a neocortex. I would like someone without a functioning neocortex to demonstrate emotion, in particular. That would be pretty hard for them, I imagine, since they would be a non-functioning vegetable.
Similarly, just because you have a CPU that apparently functions without an OS does not imply that the full functionality of the CPU is available without an OS. I would like a CPU without an OS to help me write this post, in particular. That would be pretty hard for it, I imagine, since it would be little more than a calculator.
EDIT -- I just realized there has been a miscommunication. I have been meaning to say "cortex" where I say "neocortex". So I don't think there is any contention here, I think everyone would agree that you can't have emotion without any cortex
at all.