A lot of hypotheses about autism involve... wait for it... amygdala abnormality.

Autism gets way over-emphasized here and elsewhere as a catch-all diagnosis for mental oddity. Schizotypality and obsessive-compulsive spectrum conditions are just as common near the far right of the rationalist ability curve. (Both of those are also associated with lots of pertinent abnormalities of the insula, anterior cingulate cortex, dorsolateral prefrontal cortex, et cetera. However I've found that fMRI studies tend to be relatively meaningless and shouldn't be taken too seriously; it's not uncommon for them to contradict each other despite high claimed confidence.)

I'm someone who "talks (or reads) myself into" new moral positions pretty regularly and thus could possibly be considered an interesting case study. I got an fMRI done recently and can probably persuade the researchers to give me a summary of their subsequent analysis. My brain registered absolutely no visible change during the two hours of various tasks I did while in the fMRI (though you could see my eyes moving around so it was clearly working); the guy sounded somewhat surprised at this but said that things would show up once the data gets sent to the lab for analysis. I wonder if that's common. (At the time I thought, "maybe that's because I always feel like I'm being subjected to annoying trivial tests of my ability to jump through pointless hoops" but besides sounding cool that's probably not accurate.) Anyway, point is, I don't yet know what they found.

(I'm not sure I'll ever be able to substantiate the following claim except by some day citing people who agree with me, 'cuz it's an awkward subject politically, but: I think the evidence clearly shows that strong aneurotypicality is necessary but not sufficient for being a strong rationalist. The more off-kilter your mind is the more likely you are to just be crazy, but the more likely you are to be a top tier rationalist, up to the point where the numbers get rarer than one per billion. There are only so many OCD-schizotypal IQ>160 folk. I didn't state that at all clearly but you get the gist, maybe.)