I'm going to echo this and add a bit more context. Look at the cerebellum for example. That lump at the bottom of your rear skull has ~50% of all your neurons.

I'm going to echo this and add a bit more context. Look at the cerebellum for example. That lump at the bottom of your rear skull has ~50% of all your neurons. It is extremely important for motor control. When you grab a cup of coffee as you dash out the door in the morning, your cerebellum is what is responsible for you being able to do that without looking at the cup as you reach for it. You 'know' the cup is there and you don't have to tell every nerve to fire every muscle and to extend your forearm and then grab it with only 3 fingers and then adjust for the decrease in weight with every sip. You just do it, naturally. Your cerebellum is what is responsible for that. It is a dedicated portion of your brain that really only does those kinds of things. Your hippocampus also deals with short term memory. HM was a famous patient that had his hippocampus removed, basically, and then lost all of his short term memory. Poof, gone forever. In short, your brain has dedicated areas in it that only do certain things, it is NOT some FPGA that gets re-wired on the fly. Your intelligence is not dependent on the number of connections or neurons.