As far as we know, neurofeedback trains pools of neurons in the brain.  Another type of cell, called glial cells, are far more plentiful in the brain, but glial cells remain largely a mystery to neuroscientists.  Over the next decade, I believe we will see an explosion of research into and knowledge about glial cells.  I share this article from Science Daily to point to exciting things on the horizon.  Check out “Uncovering the Power of Glial Cells” here.