Hi Ousaima,
Liver cells, except for the bile ducts, relate to the brain stem and typically show a "plus-reaction" during the stress phase. One of their functions is storing energy, even as fat. This occurs when also the alpha cells are stress-active with a "minus-reaction" of lowering glucagon and blood sugar levels which creates feelings of hunger. You eat more, and the energy is transformed to fat around the liver. So you got it right so far.
A plus in tissue can otherwise also occur in regeneration phases of new-brain related tissues, and a minus in tissue can happen in regeneration phases of old-brain related tissues.