Epilepsy and the Brain: Functions and Makeup

Seizure activity in specific areas of the brain may be expressed as disruption
of the function that controls each area.

While distinct areas of the brain are associated with distinct functions, it is also true that the brain works through a network of connections and interrelated parts. Similar functions may be located in various areas of the brain. When injury or surgery silences one area, other parts may compensate by taking over its tasks.

The brain is made up of billions of neurons, or nerve cells. These are the electrically charged units that, as they communicate with each other, organize electrical energy to make the brain work.

A neuron has three parts—a cell body, an axon, and dendrites. The enzymes and genetic material which directs the neuron are contained in the cell body. The cell body is surrounded by thin, branch-like projections, or dendrites. The axon is a long, thin, tail-like extension from the cell body, insulated by a sheath of myelin. It carries an electrical charge to the axon terminal, where it activates the release of neurotransmitting chemicals.

These chemicals cross the narrow gap, or synapse, between the end of the axon and the dendrite of the neighboring cell, locking into receptors on the dendrite membrane. The dendrites function like receiving antennas for signals from neighboring cells. Neurotransmitters are the signal that causes the receiving cell to fire, or stop firing. This function is significant for epilepsy, since excessive firing is characteristic of seizures.