I (try to) read code from popular open source projects. It's a bit like sight reading in music because the idea is that I go in blind and try to make sense of it.
This rings true to me:
> The researchers saw little to no response to code in the language regions of the brain. Instead, they found that the coding task mainly activated the so-called multiple demand network. This network, whose activity is spread throughout the frontal and parietal lobes of the brain, is typically recruited for tasks that require holding many pieces of information in mind at once, and is responsible for our ability to perform a wide variety of mental tasks.
There is language of course, but I'm not working hard to process the language so it wouldn't show up as an fMRI signal. I am often holding several things in mind at once, including things like what the code does, what the authors are trying to do, what the author's background might be, how similar software works etc.
I did study math, and it also doesn't really feel like reading or doing math.