1. The Mind In The Brain

Organisms make minds out of the activity of special cells known as neurons. Neurons are sensitive to changes around them; they are excitable (an interesting property they share with muscle cells). Thanks to a fibrous prolongation known as the axon, and to the end region of the axon known as the synapse, neurons can send signals to other cells, often quite far away. The number of neurons in each human brain is on the order of billions, and the synaptic contacts that the neurons make among themselves number in the trillions. Neurons are organized in small microscopic circuits, whose combination constitutes progressively larger circuits, which in turn form networks or systems. Minds emerge when the activity of small circuits is organized across large networks so as to compose momentary patterns.

2.The Conscious Symphony.

Conscious minds result from the smoothly articulated operation of several, often many, brain sites. The ultimate consciousness product occurs from those numerous brain sites at the same time and not in one site in partcular, much as the performance of a symphonic piece does not come from the work of a single musician or even from a whole section of an orchestra. The oddest thing about the upper reaches of a consciousness performance is the conspicuous absence of a conductor before the performance begins, although as the performance unfolds, a conductor comes into being. For all intents and purposes, a conductor is now leading the orchestra, although the performance has created the conductor – the self – not the other way around. Building a mind capable of encompassing one’s lived past and anticipated future, along with the lives of others added to the fabric and a capacity for reflection to boot, resembles the execution of a symphony of Mahlerian proportions. But the true marvel is that the score and the conductor become reality only as life unfolds. The grand symphonic piece that is consciousness encompasses the foundational contributions of the brain stem, forever hitched to the body, and the wider-than-the-sky imagery created in the cooperation of cerebral cortex and subcortical structures, all harmoniously stitched together, in ceaseless forward motion, interruptible only by sleep, anesthesia, brain dysfunction, or death.

3. Mind Maps

The patterns, or maps, of the mind represent things or events outside the brain, either in the body or in the external world. Ultimately, consciousness allows us to experience maps as images, to manipulate those images, and to apply reasoning to them. Maps are constructed when we interact with objects, such as a person, a machine, or a place, from the outside of the brain toward its interior. Maps are also constructed when we recall objects from inside our brain’s memory banks. The construction of maps never stops, even in our sleep. The human brain maps whatever object sits outside it, whatever action occurs outside it, and all the relationships that objects and actions assume in time and space, relative to each other and to the mother ship known as the organism. The human brain is a mimic of the irrepressible variety.

4. The beginning of Consciousness

Imagine holding a brain in your hand and looking at the surface of the cerebral cortex. Now imagine taking a sharp knife and making cuts parallel to the surface, at a depth of two or three millimeters, and extracting a thin fillet of brain. After fixing and staining the neurons with an appropriate chemical, you can lay your preparation down on a thin glass slide and look at it under the microscope. You will discover, in each cortical layer that you inspect, a sheathlike structure that essentially resembles a two-dimensional square grid. The main elements in the grid are neurons, displayed horizontally. You can imagine something like the plan of Manhattan. Contemplating a patch of cerebral cortex, one realizes why the idea of brain maps is not a far-fetched metaphor. One can sketch patterns onto such a grid, and when one squints a little and lets the imagination roam free, one can picture the sort of parchment paper that Henry the Navigator probably pored over when he was planning the voyages of his captains. One big difference is that the lines in a brain map are not drawn with quill or pencil; they are, rather, the result of the momentary activity of some neurons and of the inactivity of others.

5. Consciousness In Motion

Brain maps are not static like those of classical cartography. Brain maps are mercurial, changing from moment to moment to reflect the changes that are happening in the neurons that feed them, which in turn reflect changes in the interior of our body and in the world around us. The changes in brain maps also reflect the fact that we ourselves are in constant motion. We come close to objects or move away from them; we can touch them and then not; we can taste a win, but then the taste goes away; we hear music, but then it comes to an end; our own body changes with different emotions, and different feelings ensue. The corresponding brain maps change accordingly. A spectacular consequence of the brain’s incessant and dynamic mapping is the mind. The mapped patterns constitute what we, conscious creatures, have come to know as sights, sounds, touches, smells, tastes, pains, pleasures, and the like – in brief, images. The images in our minds are the brain’s momentary maps of everything and of anything, inside our body and around it, concrete as well as abstract, actual or previously recorded in memory. Perception, in whatever sensory modality, is the result of the brain’s cartographic skill.

6. The Body In The Mind

Because brain maps are the substrate of mental images, mapmaking brains have the power of literally introducing the body as content into the mind. But body-to-brain mapping has a peculiar aspect: Although the body is the thing mapped, it never loses contact with the mapping entity, the brain. Under normal circumstances they are hitched to each other from birth to death. Just as important, the mapped images of the body have a way of permanently influencing the very body they originate in. Any theory of consciousness that does not incorporate these facts is doomed to fail.

7. Sensual Windows On The World

The brain’s pervasive, exhaustive mapping of the body covers not only what we usually regard as the body proper – the musculoskleletal system, the internal organs, the internal milieu – but also the body’s spying outposts – the smell and taste mucosae, the tactile elements of the skin, the ears, the eyes. Those devices have a part made of “old flesh” and another made of delicate and special “neural probes.” Examples include the cochlea in the inner ear, with its sophisticated hair cells and soundmapping capabilities, and the retina at the back of the eyeball, onto which optical images are projected. The combination of old flesh and neural probe constitutes a body border. Because of this curious arrangement, the representation of the world external to the body can come into the brain only via the body itself. The body and the surrounding environment interact with each other, and the changes caused in the body by that interaction are mapped in the brain. Body-brain communication goes both ways, from body to brain and in reverse. The body tells the brain: This is how I am built and this is how you should see me now. The brain tells the body what to do to maintain its even keel.

8. Feel That Emotion

Emotions are complex, largely automated programs of actions concocted by evolution. The actions are carried out in our bodies, from facial expressions and postures to changes in viscera and internal milieu. Feelings of emotion, on the other hand, are composite perceptions of what happens in our body and mind when we are emoting. As far as the body is concerned, feelings are images of actions rather than actions themselves. While emotions are actions accompanied by ideas and certain modes of thinking, emotional feelings are mostly perceptions of what our bodies do during the emoting, along with perceptions of our state of mind during that same period of time.

9. Conscioussness Observed

Consciousness is a state of mind – if there is no mind there is no consciousness. The conscious state of mind is experienced in the exclusive, first-person perspective of each of our organisms, never observable by anyone else. We can amplify this definition by saying that conscious mind states always have content: They are always about something. Finally, conscious states of mind are possible only when we are awake. Conscious states of mind are felt.

10. The Autobiographical Self

Autobiographies are made of personal memories, the sum total of our life experiences, including the experiences of the plans we have made for the future, specific or vague. Autobiographical selves are autobiographies made conscious. They draw on the entire compass of our memorized history, recent as as well as remote. The social experiences of which we were a part (or wish we were) are included in that history, and so are memories that describe the most refined among our emotional experiences, namely, those that might qualify as spiritual. As lived experiences are reconstructed and replayed, their substance is reassessed and inevitably rearranged, modified minimally or very much in terms of their factual composition and emotional accompaniment. Entities and events acquire new emotional weights during this process. Some frames of the recollection are dropped on the mind’s cutting-room floor, others are restored and enhanced, and others still are so deftly combined either by our wants or by the vagaries of chance that they create new scenes that were never shot. Given the abundance of records of one’s lived past and anticipated future, we do not need to recall all of them or even most of them to operate in autobiographical mode. Not even Proust would have needed to draw on all of his richly detailed and long-ago past to construct a moment of full-fledged self-Proustiness.

11. The Reflective Self

Systematic discovery of the drama of human existence and its compensations was arguably possibly only after the development of full human consciousness – a mind with an autobiographical self that is capable of guiding reflective deliberation and gathering knowledge. Eventually, given the probably intellectual capability of early humans, it is likely that they would have wondered about their status in the universe, something akin to the “where from” and “where to” questions that still haunt us today. That is when the rebellious self comes of age. That is when myths are developed, when social conventions and rules are elaborated, leading to the beginnings of a true morality. I suggest that the engine behind these cultural developments is the homeostatic impulse – the dynamic process by which the brain regulates life. In one form or another, cultural developments respond to detection of an imbalance in teh life process, and they seek to correct it.

12. Why Consciousness Prevailed

Traits and functions rise or fall in the history of life depending on how much they contribute to the success of living organisms. The most direct way of explaining why consciousness has prevailed in evolution is to say that it has contributed significantly to the survival of the species so equipped. Consciousness has flourished. It seems to be here to stay. What did it actually contribute? The answer is a large variety of apparent and not-so apparent advantages in the management of life. Even at the simplest levels, consciousness helps the optimization of responses to environmental conditions. As processed in the conscious mind, images provide details about the environment, and those details can be used to increase the precision of a much-needed response, for example, the exact movement that will neutralize a threat or guarantee the capture of prey. But the lion’s share of the advantage comes from the fact that the conscious mind infuses the exploration of the world outside the brain with a concern for the first and foremost problem facing the organism: the successful regulation of life.

Source: December 2010 issue of Discover