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The Brain: The Cerebral Cortex

brain-lobes-diagram

The cerebral cortex is the intricate fabric of interconnected neural cells that covers the cerebral hemisphere. It serves as the ultimate control and information processing centre. Humans have larger cortexes which enables us to be more adaptable, which gives us the ability to learn and think beyond basic survival instincts.

The cerebral cortex is made up of a sheet of cells that is 1/8 of an inch think and contains approximately 30 billion nerve cells. Glial cells or glue cells as they are commonly called, hold the nervous system together. They are NOT neurons but their own category of cells. Glial cells serve to support, nourish and protect neurons by communicating with them. Scientists are currently attempting to find connection between glial cells and information transmission and memory.

brain lobes

Folds of the brain increase the brain’s surface area allowing for maximised function and activity. As most people know, the brain’s cerebral cortex consists of four lobes: the parietal lobe, the occipital lobe, the temporal lobe and the frontal lobe. The frontal lobe is the front portion of the cerebral cortex, lying right behind the forehead. The frontal lobe is involved in speaking, muscle movement, high level cognition (planning, judgment, reasoning). Damage to the frontal lobe can result in changes in social skills, libido, attention and risk-taking. The parietal lobe is the part of the cerebral cortex at the top of head, behind the frontal lobe towards the back. It includes the sensory cortex. This means the parietal lobe processes sensory information such as pain, touch and pressure. Damage to the parietal lobe results in sensory problems such as impaired verbal memory and language skills. The occipital lobe lies at the base of te head and includes the visual areas; it receives visual information from the opposite visual field. This means that what is seen by our right is processed by the left side of our occipital lobe and vice versa. The temporal lobe lies above the ears and includes the auditory areas. These two areas receive auditory information from the opposite ear much like how the eye and occipital lobe work. 

– Functions of the Cerebral Cortex –

German physicians Fritsch and Hitzig electrically stimulated the cerebral cortexes of dogs. Through their experiments, Fritsch and Hitzig found that they could make different parts of the dogs’ bodies move. However, their ability to make the dogs move through stimulation was selective. Movement was only observable when a specific arch-shaped area of the back of the frontal lobe was stimulated. This area is know known as the motor cortex. Furthermore, the physicians discovered that the parts of the body that were moved, corresponded to stimulation on the opposite side of the brain.

Neurosurgeons Foerster and Denfield also investigated the functions of the cerebral cortex through stimulation. They found that precise control requires the greatest amount of cortical space. Furthering this idea, Jose Delgado found that specific parts of the cerebral cortex correspond with certain actions. Today it is evident, through the use of MRI scans, that precise actions require overlapping cortical sites.

brain lobes 2

The cerebral cortex specialises in receiving information from the skin senses and the movement of body parts. The greater the area devoted to specific body region, the more sensitive this area becomes. As a paradigm, our lips are far smaller than our back; however, relative to size, the cerebral cortex dedicates far greater area to our lips making them far more sensitive and kisses so enjoyable. It also explains why our backs are far less sensitive to pain than say our stomachs.

– Association Functions – 

The association areas consist of 3/4 of the cerebral cortex. Association areas are uncommitted to sensory of muscular activity. They associate with various sensory inputs with stored memories. The functions of the association areas cannot be triggered by stimulation or any other forms of probing. The existence of these areas are vital in disproving the popular belief that 90% of our brain is dormant. Our brain relies heavily on these unassociated areas for interpretation, integration and acting on processed sensory information.

Citations:

Cherry, Kendra. “The Anatomy of the Brain.” The Four Lobes (2012): n. pag. About.com Psychology. Web. 03 Sept. 2012. <http://psychology.about.com/od/biopsychology/ss/brainstructure_2.htm&gt;.

Myers, David G. Psychology . 6. Worth Publishers, 2001. Print.Myers, David G. Psychology . 6. Worth Publishers,2001. Print.