Literature Supports Trigger-Dispersion Theory :: Biology Essays Research Papers

Literature Supports Trigger-Dispersion Theory Having seen epileptic seizures and talking qualitatively about the experience with people who have epilepsy, I made five basic hypotheses about epilepsy. I collectively call these hypotheses my trigger dispersion theory of epilepsy. My five hypotheses are: 1 There is an area in the brain where abnormal firing associated with seizures begins. I will call this area the trigger area. From the trigger area, abnormal firing spreads to other areas of the brain compromising the function of the affected area. 2 There is a stimulus either external or internal which excites the trigger area. I will call this stimulus the trigger. The trigger can be very specific. 3 The first area affected after the trigger area is sensory. 4 The abnormal firing spreads from the sensory area to an area for motor control. In this paper, I will go through the hypotheses of the trigger-dispersion theory and discuss literature that supports each hypothesis. Hypothesis 1- There is an area in the brain where abnormal firing associated with seizures begins. I will call this area the trigger area. From the trigger area, abnormal firing spreads to other areas of the brain compromising the function of the affected area. During a seizure, certain cells (a seizure focus) begin to fire rapidly. In fact, nerve cells in the brain fire electrical impulses at a rate of up to four times higher than normal during a seizure (5) . This abnormal firing is spread this to other neighboring cells. In the brain of an epileptic, there is not enough inhibitory neurotransmitters to stop the spread of the abnormal firing (2) . In the 1800s, it was noted by Jackson that epileptic seizures begin in isolated parts of the body such as the thumb and from there spread to neighboring regions perhaps the arm and then to the rest of the body. He hypothesized that there were areas in cerebral cortex that controlled isolated movements and that the areas that were adjacent in the brain were anatomically adjacent as well. Therefore, a seizure began in one area and spread to the rest of the cortex. His hypothesis was later substantiated by Fritsch and Hittig's excitation experiments on motor cortex or area 4. It is a band of neural tissue on the cerebral cortex lying on precentral fissure. The body's movements are mapped out on this band giving rise to the spreading fashion that Jackson described during seizures (6) .