Final Thoughts on Vitamin B12 Injections. 1  Vitamin B12 injections (or shots) are used to overcome vitamin B12 deficiency, which is common especially among the elderly, those with intestinal damage or disorders, people with pernicious anemia, and vegetarians/vegans.
Neurons communicate over long distances by sending signals called nerve impulses through the axons which make up a tract or nerve. Because each axon may branch into a whole tree, and because nerve impulses go down each branch when an axon divides, a single neuron may send signals to thousands of other neurons.
Cortical neurons communicate with each other at junctions called synapses, located at hundreds of sites on the outer surface of any given cell. At a synaptic site, two cell membranes come into proximity, and both of them have lots of molecular structures called receptors that enable them to receive messages from each other.