Epilepsy

Epilepsy is a neurological disorder due to abnormal electrical brain activity. The brain is overly stimulated, causing seizures and period of unusual behaviors, feelings, or loss of awareness. An aura is a certain sign or “strange feeling” one has when they are about to have a seizure. It acts as an early warning system, and helps one minimize injury by taking precautions such as sitting down. Epilepsy is defined as a state of reoccurring, spontaneous seizures, and epileptogenesis refers to the sequence that causes the brain to be in such a state. Seizures occur when there is a disruption of the mechanisms that balance excitatory from inhibitory neurons. The balance tips towards the excitatory response, resulting in increased brain stimulation and electricity.

Partial seizures are the most common type of seizure, which result from a hyperexcitability of CNS neurons. For a seizure to occur, an adequate number of neurons must depolarize and enter PDS (Paroxysmal Depolarization Shifts), where the cell membrane experiences high voltage and depolarization. This depolarization is longer than normal, and causes a domino affect of action potentials that are conducted away from the soma of the neuron (in the axon). This is followed by a period of hyper-polarization, which is generated by ionic channels, including GABA and Ca2+ -activated K+ channels. During a seizure, the neurons remain in a state of depolarization, with frequent bursts of action potentials, but without a period of re-polarization to intervene between the two. In the next stage, large inhibitory potentials occur and alternate with recurrent rhythmic PDS.

Recent studies have revealed the relationship between epilepsy and synaptic plasticity. Seizures in the adult brain may lead to various affects in synaptic plasticity, which affects the hippocampus and the ability to form new memories.

There are still so many questions about epilepsy that are left unanswered and can be further studied! If you would like to learn more, click the link below!