Part Two of a Two-Part Series.
The dominant anatomical feature of our brain is the undulating surface of the cerebrum – the deep clefts are known as sulci and its folds are gyri. The cerebrum is the largest part of the brain and is largely composed of the two cerebral hemispheres. In terms of evolution, it is the most recently developed brain structure, dealing with more complex cognitive brain activities.
It is often said the right hemisphere is more creative and emotional while the left deals with logic, but the reality is more complex. Nonetheless, the two sides have some specializations, with the left focusing on speech and language and the right focusing on spatial and body awareness.
Further anatomical divisions of the cerebral hemispheres are the occipital lobe at the back of the brain and the parietal lobe positioned above the occipital lobe. The former lobe is devoted to vision, while the latter controls movement, position, orientation and calculation.
Behind the ears and temples lie the temporal lobes, dealing with sound, speech comprehension and some aspects of memory. To the fore are the frontal and prefrontal lobes, often considered the most highly developed and most “human” of regions, controlling thought, decision making, planning, conceptualizing, attention control and working memory. They also deal with various social emotions such as regret, morality and empathy.
Another classification is the sensory cortex and motor cortex, controlling incoming information and outgoing behavior, respectively.
Below the cerebral hemispheres, but still referred to as part of the forebrain, is the cingulate cortex, which directs behavior and pain. Beneath it lies the corpus callosum, connecting the two sides of the brain. Another significant area of the forebrain is the basal ganglia, responsible for movement, motivation and reward.
Beneath the forebrain lie more primitive brain regions. The limbic system, common to mammals, deals with urges and appetites. Meanwhile, the brain structures of the amygdala, caudate nucleus and putamen are most closely linked with emotions. The limbic brain also houses: the hippocampus – vital for memory formation; the thalamus – a sort of sensory relay station; and the hypothalamus, which is reponsible for regulating bodily functions.
The back of the brain has a highly convoluted and folded swelling called the cerebellum, which stores movement patterns, habits and repeated tasks – actions we perform without much thought.
The most primitive parts, the midbrain and brain stem, control the bodily functions we conduct subconsciously, such as breathing, heart rate, blood pressure, and sleep patterns. These parts of the brain also control signals that pass through the spinal cord between the brain and the rest of the body.
Though we have discovered an enormous amount of information about the brain, crucial mysteries remain. For instance, how does the brain produces our conscious experiences?
The majority of the brain’s activity is subconscious. But our conscious thoughts, sensations and perceptions, which define us as humans, have yet to be explained by brain activity.
About the Author – Terry A. Rondberg, DC.
Dr. Terry Rondberg received his Doctor of Chiropractic (DC) at Logan College, and has gone on to found the World Chiropractic Alliance, The Chiropractic Journal, and author several books on chiropractic and wellness.