Now they're here, living together in this civilization we call brain, but they are still feral. In a very real way they rival and tussle each day to stay alive. The neurons of the brain do not grow old and die like other cells; you have almost entirely the same brain cells now that you had when you were a child. However, tens of thousands of them are wiped out every day - only the ones that form important constellations and alliances with other neurons receive neuromodulators and grow; others shrivel and fade. Neuromodulators, what Gerald Edelman calls 'value systems', are essential to the life and growth that brain cells seek.

And here is the essential fact: neuromodulators are released in the brain in response to meaningful events of various kinds, happenings internal or external that bear on the interests of the body, the person, the brain as a whole, or one of its neural communities. The brain cells, seeking neuromodulators, seeking life and growth, are therefore in constant electrical communication and structural flux, seeking to bring about, probe and explore the meaningful, important aspects of the reality in which they find themselves.

What are these aspects of interest, of meaning? What happenings attract the astronomical complexity and potential of a living human brain cell? To start with, every neuron is in constant electrical union with the sensing, moving body, and they communicate and grow about this vital fact. They share a common path through life, so they explore and probe their shared memories constantly for nuggets of intrigue. Although their communities are often in tension as each continues the ancient will to live on and grow against the daily weeding out of the least relevant of them, they nevertheless share a common mouth, a common pair of hands and eyes, and the electrical urges of hunger and need and sleep and dreams reverberate across the neural fields endlessly.

How could they not share a sense of I in this circumstance? From this seeking, seething, astronomically complex swirl of electric neural energy, membrane and will to survive and grow emerges pleasure and frustration, I and not-I, hopes, plans, dreams and distinctions. The astounding communities and constellations of living, electrified tissue that constitute each of these core features of the human experience are there for us to explore, by any method we choose - introspective, statistical, fictional, spiritual, communal - and it is our tremendous fortune and grace to be alive just as the technology to express and understand all of this fully is finally beginning to become available.

But at the heart of it all is an ancient electric civilization of cells, seeking nourishment and love and excitement and force, in a never-ending myriad of ways. This is what it is to be alive, a conscious human being.

Electricity is key; the near-instantaneous sharing of the tremendous depth of memory, will and rich experience among these one hundred billion little lives within that one skull. It is in their nature to seek, like their cousins still independent in the sea, but the cells of the brain seek in communication and structural union with other brain cells. The subject of this electrical conversation is and feels like you.