Area indicates a number of nerve cells in the cortex (the name given to the layers of nerve cells on the surface of the brain) which are in some way abnormal, tending to discharge paroxysmally. They may drive other nerve cells to follow their abnormal patterns of discharge. The paths of influence of the discharging nerve cells are indicated by the arrows. As long as the discharge remains in one part of the brain, the seizure is said to be a partial seizure and its cause

location-related. What happens during a partial seizure depends upon the exact site and pattern of discharge of abnormal nerve cells. Temporal lobe seizures are of this type.

The abnormal discharge may spread through the connections linking the two halves of the brain, or, by affecting poorly identified central collections of cells, initiate a generalized seizure discharge, in which case the seizure is said to be a partial seizure with secondary generalization (to a convulsive seizure—grand mal). These are also known as tonic-clonic seizures).

The second main class of seizure. In this class of seizure, central collections of nerve cells are in some way abnormal in their behaviour—even though they may appear to be perfectly normal under the microscope. Because of their central position, and the direction and power of their transmissions, a seizure discharge generated within them spreads more or less simultaneously to all parts of the brain. Such a seizure is generalized at onset. Typical absences (often known as petit mal), and some grand mal seizures, are of this type.


Google Bookmarks Digg Reddit Ma.gnolia Technorati Slashdot Yahoo My Web
Written by admin in: Epilepsy |

No Comments

RSS feed for comments on this post.

Sorry, the comment form is closed at this time.

Powered by WordPress | Aeros Theme | WordPress Themes