glia: support the metabolic and the signaling functions of neurons, which often involves both electrical and chemical signals. () participate in the forming of neural circuits and in a variety of forms of synaptic ______. This is a very exciting, new aspect of glial cell biology that's just now beginning to open up. And we're coming to see glial cells as really being active participants in the process of making new synaptic connections in the brain. Certain types of glia, they make myelin, which is a form of insulation around axons that aids significantly in the propagation of electrical signals along this component of the neuron. Glia contribute to the formation of the ________-brain barrier. Glia participate in the ________ response in injured neural tissue, and that includes phagocytosis of cellular debris. Other types of glial cells contribute to the formation of ______ tissue in damaged brain and spinal cord, and so this is part of the way that the brain responds to injury.