Question: If there are about 100 billion brain cells what happens if you have more?

Omur Tastan answered on 14 Mar 2016:

My guess is we would be able to do more compared to now. Because each and every neuron is pretty much important and having more neurons would give us the ability to process more information.

The opposite is true. People with less neurons, depending on which neurons, lose their ability to do certain things. Some old people tend to sleep less because sleep neurons die as we age.

Or sometimes when people have a stroke, that can kill neurons and that person might lose some their abilities due to loss of neurons.