Neuronal Mechanisms

Seizures originate in a group of neurons that do not have normal electrical behavior. Presumably, this is due to an underlying imbalance of neurotransmitter function as described above. At the level of the individual neuron, firing is excessively prolonged and repetitive. Instead of firing a single action potential, these neurons stay depolarized too long, firing a train of many action potentials. This long, abnormal depolarization is called a paroxysmal depolarizing shift (PDS).

The excessive electrical discharges can spread to other neurons, either adjacent ones or distant ones connected by fiber tracts. The seizure thus spreads to other areas of the brain, recruiting them into the uncontrolled firing pattern. The neurons involved may not be abnormal themselves, but are diverted from their normal functioning to participate in the wildly excessive discharges. The degree of spread and the location of brain areas involved determine the clinical manifestations of the seizure.

Nearly all seizures stop spontaneously, because after seconds to minutes, brain inhibitory mechanisms become strong enough to shut off the abnormal excitation.

Blood Pressure Health

Blood Pressure Health

Your heart pumps blood throughout your body using a network of tubing called arteries and capillaries which return the blood back to your heart via your veins. Blood pressure is the force of the blood pushing against the walls of your arteries as your heart beats.Learn more...

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