Weighing in at about three pounds, the brain is the most complex part of the human body. It interprets of the senses, initiates movement, and controls our behavior. The brain takes all information relating to the body’s internal and external environments, and produces the appropriate responses.
In humans, the nervous system is divided into the central nervous system (CNS), which consists of the brain and spinal cord, and the peripheral nervous system (PNS), which contains all the nerves that run through the body. The brain both defines our humanity and acts as the control center for the human body. Protecting the brain are the meninges, which cover the cerebrum. These strong membranes cover the brain and spinal cord, with cerebrovascular fluid flowing between them.
The cerebrum is the largest part of the brain and is the part responsible for consciousness. The conscious and its counterpart unconscious is critical for the brain mind connection. The cerebrum is divided into left and right halves, which are called cerebral hemispheres. Each cerebral hemisphere has four lobes: frontal, parietal, temporal, and occipital. Identified areas of the lobes are responsible for certain functions, such as concentration, understanding speech, recognizing objects, and memory. At the center of the brain are the thalamus and hypothalamus, which form the structure called the diencephalon. The hypothalamus generates many neurosecretions, which are carried to the pituitary gland at the base of the hypothalamus. The hypothalamus controls homeostasis by regulating hunger, thirst, sleep, body temperature, water balance, and blood pressure. The pituitary gland is often referred to as the master gland because, along with the hypothalamus, it helps to maintain homeostasis by secreting many important hormones.
Scientists and philosophers have long investigated the human brain, but until recently they viewed the brain as nearly incomprehensible. What we have now learned is that the two frontal lobes working well when we plan a schedule, imagine the future, or use reasoned arguments. The motor area aids in the control of voluntary movement and allows thoughts to be transformed into words. When we sit down to enjoy a good dinner, we tap into the parietal area as we realize the taste, aroma, and texture of the food we eat. These areas receive information about temperature, taste, touch, and movement from the rest of the body. Reading and math are functions in the repertoire of each parietal lobe. When we read a book or explore fine artwork, the occipital lobes process images from the eyes and link that information with images stored in memory. Finally, the temporal lobes, which lie in front of the occipital area and nest under the parietal and frontal lobes, allow us to appreciate symphonies or other types of music and retrieving memories, associated with the music we are hearing. This is also the area of the brain that integrates memories and sensations such as smell, taste, sound, touch and sight.
The human mind has intrigued scientists, philosophers, theologians and others for centuries. In many ways it is the filter that addresses everyday life, influenced by genetic and environmental factors. For Freud, who gained considerable attention as to how the mind works, the unconscious was central. Freud believed that the unconscious explained what happens to ideas that are repressed and he stated explicitly that the concept of the unconscious was based on the theory of repression. He postulated a cycle in which ideas are repressed, but remain in the mind, removed from consciousness, and then reappear in consciousness under certain circumstances. These repressed ideas may even be retrieved through hypnosis. Freud is credited with introducing the concept of trauma; individuals who experience traumatizing events repress those events if they are too difficult to deal with at the time. The concept and diagnostic entity of Post-Traumatic Stress Disorder (PTSD) as reflected in the DSM-5 has its roots in the thoughts and writings of Freud. Freud instinctively divided the mind into three parts id, ego, and superego, in much the same way that Plato hypothesized the soul was divided into three key elements: appetitive, spirited, and reasoning.
Both the human brain and its mind are most complex elements of the human organism. Through modern brain imaging devices, scientists can actually peer into the living human brain in real time as it solves problems, processes information, and imagines the future, and future technologies will aid us in gaining greater understanding of the wonderful brain-mind entity.
About the Author
Thomas W. Miller, Ph.D. ABPP is a Professor Emeritus and Senior Research Scientist, Center for Health, Intervention and Prevention, University of Connecticut and retired service chief from the VA Medical Center and tenured Professor in the Department of Psychiatry, College of Medicine, University of Kentucky.