An Overview of Brain Anatomy

Technically, there may be no known neural correlates of consciousness at this time that are agreed on by all researchers. However, several major brain areas have been grouped according to their general functions, with hundreds, probably thousands, of other structures tentatively associated with more specific processes. Our ideas about brain anatomy are a rough sketch at best, missing important details, but many structures have been commonly identified by many different researchers.

Here, we will take a look at some of the major divisions of the brain. Then the neocortex will be explored a bit more, because its kind of important.

The hindbrain: This is the oldest part of the brain, and it consists of the medulla, pons, and the cerebellum. It is sometimes referred to as the 'reptilian' brain, and seems to deal mostly with our basic survival needs. The structures of the hindbrain regulate autonomic bodily functions such as breathing, swallowing, digestion, and body posture. It also keeps an eye out for danger.

The midbrain: Consists mostly of the tectum, and is involved with processing sensory and motor functions. It connects the hindbrain with the forebrain. This structure, along with the hindbrain, is referred to as the brainstem. Not much is often said about the midbrain.

The forebrain: Consists of the thalamus, hypothalamus, and neocortex, which, along with 'lateral geniculate nucleus' is a candidate for “coolest name in the brain.” The thalamus is a relay station of sorts. It receives sensory information which it organizes and passes on to the appropriate areas of the neocortex. The hypothalamus is a very busy piece of brain that is best known for its role in maintaining homeostasis of the body. It is involved with blood pressure, eating, general arousal, rage, escape reflexes, pleasure, and much more.

The Neocortex: Or cerebral cortex. Or just cortex. Its the very newest part of the brain, and humans have the newest one still. The cortex has probably frustrated more researchers than any other. It is subdivided in many, many, ways (it requires long division), the most prominent being the separation into hemispheres, whose functions complement each other.

The left hemisphere: Is generally involved with activity on the right side of our bodies. In most people (but less left-handed people than right-handed people) this side of the brain is more actively engaged during language use (speaking, reading, etc..) than the right hemisphere. It is also more involved with conscious attention, logic, and sequential processing. It can kind of be thought of as the laser-focus aspect of the brain.

The right hemisphere: Is, on the other hand, generally involved with activity on the left side of our bodies. It is more involved (often called “better”) at non-verbal representation, spatial relations, and pattern recognition, such as faces. It seems to be proficient at parallel processing, seeing relationships and “the big picture.” It can kind of be thought as the floodlight aspect of the brain in contrast to the laser-focus aspect of the left hemisphere.

The hemispheres are connected through the corpus collosum, a thick band of nerve fibers that carry information between the left and right cerebral hemispheres.

Getting more specific, the cortex is also divided into the frontal, temporal, parietal, and occipital lobes. Each of these, remember, has a left and right hemisphere.

The Frontal lobe: Often thought of as the executive decision-maker because of its role in the higher cognitive functions such as planning for the future, emotions, language, and judgment. It is also involved with problem solving, attention, and social behavior.

The Temporal lobe: Highly involved with the processing of auditory and olfactory information. Also, learning, memory, and emotion are correlated with this area.  

The Parietal lobe: Involved with sensory and motor information processing, and the integration of the two. It handles much of the processing for our senses of touch, motion, and spatial representations.

The Occipital lobe: Is located at the very back of the brain and seems to be dedicated to processing visual information. This includes determining shapes, colors, sizes, locations, and sending this information to various parts of the brain.

Hopefully this has provided an overview of the major functional areas of the brain. Repeating the same functions across different areas was not a mistake; many functions are shared across many brain areas.

Seems almost simple, right? Match up our subjective, conscious experience with those areas of the brain that light up at the same time. Researchers can chip away at this task, and the mysteries of consciousness will dwindle and be described in obscure anatomical terminology.

However, within the realm of science, certainty is the devil. Next time, we'll take a look at the conundrum of the Boy With No Brain, as well as some modern research of the neural correlates of consciousness.