We like to think of ourselves as singular beings, as individuals with one brain, mind and consciousness. But this is mostly a consequence of the fact that we can treat our hyper-connected brain as one network.
Yet that network isn’t perfectly uniform. Some parts have specific functions and the whole thing is made up of two almost completely separate main sections — left and right hemispheres — that are connected by a narrow band of long neurons right at the base that allows signals to pass from one side to the other.
This band of neurons is called the corpus callosum. Besides this link, there is very little directly connecting the two hemispheres. So, the brain is much more like a bunch of different networks, some very specialised, all connected together into two hemispheres, which are then connected by a bridge.