I'm looking at this video: Neil Burgess: How your brain tells you where you are, which discusses neurons within the brain that help people remember where stuff is in relation to other objects.
I'm interested if there are similar kinds of neurons or areas of the brain that are specifically involved in recognizing heights. For example, I can be looking at a flat suface across horizontal distance and I feel fine (for example looking at a distant building). But if I'm looking at another flat surface, of the same distance, but straight down, I may feel uneasy. This feeling of unease tells me that an additional mechanism may be involved in perceiving heights.
The question is - what part of the brain can differentiate horizontal distance from vertical drop?