OK, putting together the latest research, see if this helps to explain it...
In an ordinary brain, when we're born there seems to be an 'telephone cable construction crew' in the brain that wires it up in the usual way. Think of it as a big office block with lots of departments in it who all need to be connected. In a normal brain you get the eyes, ears, skin, tongue, nose etc all connected up to the middle bits so they can all talk to the brain and it can sort all the info into useful/not very useful/can't be bothered. It spends most of its time checking and cross-checking the info and working out what's the same and what's different and how to spot things that might be the same. New wiring happens all the time, so if you see something that might be a cat or a dog, you can guess which.
But in the autistic brain, for some reason, the construction crew gets given a new set of instructions somehow. Instead of building a network connecting everything together as normal, they build a superfast broadband connection to some bits, and almost forget the wiring for the rest, and 'dig up' some of the old cabling and move it round. So incoming info from the eyes, ears, taste buds etc doesn't really get to anywhere useful, or does get there but really slowly and in a big queue of other incoming facts all hoping to get through to the phone the other end. The superfast bits become the 'special interests' and strange abilities many have. It also explains what happens to us when we can seem deaf or blind or badly co-ordinated - the messages just aren't getting through properly. Result - we're not at all sure what's a cat and what's a dog unless we think about it a heck of a lot. We might not hear you if we're looking at something, but what we do hear and what we do see is amazing to us. It's all very different to your brain.
Can it rewire again? Probably yes. Maybe manually, though, rather than automatically. Much debate on this. For a start, some of the new wiring is actually often very handy, so we wouldn't want to lose that bit.
Frustrating for those parents watching children's skills changing, though. Very.