Is the Brain Learning From Scratch?

It's possible that learning from scratch has already been happening in the womb, for example. You don't really need sensory inputs to learn to control your own body. So you can have a reinforcement learning algorithm related to motor control. That would be learning from scratch, but it can already start in the womb. And it doesn't really need to be learning from the outside world. My hypothesis is that 96% of the brain is learning from scratch in that sense. The hypothalamus and brain stem are not learning from scratch at all.