The difference between a dormant brain and a living one is electrical pulses that surge through the latter. Of course, a dead brain also has no blood flowing through it, produces no frequencies, and lacks a number of other faculties, but I propose that these are merely the effect of the loss of that signal that travels through the brain, into the body, and then back to the brain. Following this logic, perhaps what most human beings conceive as "the soul", is actually that "spark", or perhaps is held in that "spark".
It is only after much deliberation I've come to this conclusion. If you can swallow what I've said up to here, a number of questions can be answered. The first is the question of when exactly a fetus becomes a "person". I suggest that it is when the baby first has the spark of life, or electrical pulses through his brain. The cerebral cortex does not form until after the second trimester, providing a fully functioning brain. This is when I think the baby receives the spark.
Of course, this leads to the question: where does the spark come from? I have no good way of answering this question without first segueing into another question. What happens to the spark when a person dies?
To answer this we must examine the nature of electricity. When an electric pulse reaches a synapse, it jumps the gap to another suitable conduit. It is my belief that this leads to a sort of reincarnation: the "dead" signal jumps to a newly forming baby, thus continuing its transmission. This answers my former question of where the spark comes from. Obviously, the spark contains no memory of where it has formerly been; it merely starts the consciousness of the fetus.
It is not a new idea that electricity is the source of life: look no further than Mary Shelley's Frankenstein, where a dead body is resurrected through electricity. I simply took this idea and furthered it to include the idea of birth (receiving the spark), death (a synapse), and afterlife (the spark being received again).
The connection to a soul is not as direct as I at first suggested. All living beings, I believe, have the spark of life, while the soul is simply an idea that Man created to explain his existence.
This is the most logical and reasonable notion I have found to the creation of consciousness and the loss of it. Thus, being a logical person, I believe it whole-heartedly. The only thing I find to be almost supernatural is the reincarnation aspect, and would agree that it is equally as likely that the electrical current simply runs into the ground like lightning, where it is smothered into nothingness. If this were the case, I would guess that the mother sends the pulse to her fetus when the brain is fully functioning.