Abnormal synchronous discharging

A seizure is a sudden attack of pain, a disease or certain symptoms which could be due to bursts of abnormal synchronous discharging caused by a network of neurons. It is quite obvious that till date no exact mechanism (s) of seizure induction could be explained scientifically, but the following possible reasonings may be put forward, such as ... 

Seizures result from bursts of abnormal synchronous discharging by a network of neurons. Although the mechanisms of seizure generation are still poorly understood, the causes of abnormal firing appear to involve neuronal ion channels and an imbalance between excitatory and inhibitory synaptic function. Various AEDs exhibit different mechanisms of action on neuronal function, causing them to show selective efficacy against different seizure types (Fig. 20.2). 

That an episode arises and spreads from the synchronous as well as excessive discharge of a group of neurons (focus) means that not only must those neurons be in some way predisposed to so discharging but they can also recruit neurons that are otherwise normal. How that discharge manifests itself, i.e. which type of epilepsy occurs, will depend not only on where the abnormal focal neurons are located but also to what extent the activity they initiate can and does spread through the brain. There are consequently a number of different forms of epilepsy, i.e. the epilepsies. 

Epilepsy is a chronic brain disease of diverse etiology it is characterized by recurrent paroxysmal episodes of uncontrolled excitation of brain neurons. Involving larger or smaller parts of the brain, the electrical discharge is evident in the electroencephalogram (EEG) as synchronized rhythmic activity and manifests itself in motor, sensory, psychic, and vegetative (visceral) phenomena Because both the affected brain region and the cause of abnormal excitability may differ, epileptic seizures can take many forms. Erom a pharmaco-therapeutic viewpoint, these may be classified as ... 

In CONCLUSION, epilepsy is a term used to describe a variety of recurrent symptoms which result from the synchronous or sustained discharge of a group of neurons. It is not clear which specific abnormality in synaptic function is associated with epilepsy, but there is some evidence that an impairment of inhibitory transmission in the neocortex and hippocampus may be primarily involved. The possible causative role of GABA is supported by the fact that many clinically useful anticonvulsants facilitate GABA transmission. Other anticonvulsants may owe their efficacy to their ability to stabilize cation movements across neuronal membranes and /or to affect the phosphorylation of membrane proteins. 

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