THE KINDS OF SEIZURE: GENERALIZED SEIZURES – PARTIAL (FOCAL) SEIZURES AND THE ANATOMY OF THE BRAIN
February 26th, 2011In order to understand partial or focal seizures and their many manifestations, it is necessary to understand something about the anatomy of the brain. Indeed, it was from a careful study of the events that occurred during partial or focal seizures that Dr. Hughlings Jackson, considered the father of modern understanding of epilepsy, first deduced the organization of the brain. He watched the slow spread of focal seizures (subsequently called Jacksonian seizures) from the finger to the hand to the arm and then to the face, and reasoned that these areas must be next to one another in the brain. The result was the identification of a continuity, the anatomy of the motor strip.
These deductions subsequently have been confirmed by Dr. Wilder Penfield and Dr. Herbert Jasper, who, during operations to remove tissue responsible for focal epilepsy, stimulated areas of the brain with small amounts of electricity. Depending on which area was stimulated, a finger would move, a foot would jerk, the face and tongue would twitch, or a finger or lip would tingle. Even certain memories or visions would be recalled. Minute electrical stimulation is used even today to “map the brain” before a surgeon removes electrically-abnormal brain tissue so that tissue important to normal function can be identified and avoided during the surgery.
As the human brain has evolved, its “thinking and processing” parts have become greatly enlarged. This “thinking” part of the brain is the cortex. The cortex has four major sections called lobes, responsible for separate functions. The frontal lobes are responsible for personality and memory. The temporal lobes on the left side (in most people) control speech and on the right control subtle higher functions such as spatial recognition and music. The parietal lobes contain areas for making associations and interpreting sensations, such as the ability to recognize objects placed in the hand. The occipital lobes are the site of processing vision.
The left side of the brain controls movements of the right side of the body and receives sensation from the right side of the body. Thus, the left occipital lobe processes vision from things in your right field of vision, and the right side of the brain processes similar functions for the left side of the body.
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