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.
Therefore, neurotransmitters make possible the nerve impulses of one cell influence the nerve impulses of another, thus allowing brain cells to talk to each other, so to speak. The human body has developed a large number of these chemical messengers in order to facilitate internal communication and signal transmission within the brain.