Epilepsy is a neurological disease where seizures, due to abnormal and excessive brain activity, occur suddenly and without warning.
Many different epileptic syndromes exist, involving different brain areas and with different evolutions. In France, about 500,000 people suffer from epilepsy. 40% of epilepsies are associated with a brain injury, such as a congenital malformation, or resulting from a brain infection, diffi culties at birth, head trauma, tumour or after stroke. 10-25% of epilepsies have a genetic component.
The causes of epilepsies are not psychological but involve physical changes in the brain. There are two major types of seizures: generalized seizures that are also called tonic-clonic and that involve large brain areas and partial seizures that seem to start from a focal site.
Therapies could be greatly improved for many epileptic syndromes. No available drug can eliminate seizures and even if seizure frequency can be reduced, side effects are often undesirable.
THE Institut du Cerveau – ICM’S RESPONSE
The Institut du Cerveau – ICM’s research objective is to develop new therapies for epilepsy, which not only seek to ease seizures but also prevent their origins. To address this problem, Richard Miles’ group
uses electrophysiology on slices of tissue to understand the mechanisms of the onset of seizures – what causes many thousands of neurons to be active all at the same time and setting off an electrical «hurricane» in the brain. These experiments are carried out on epileptic tissue, collected during surgical operations, and kept alive for up to 12 hours.
Stéphane Charpier’s group works to better understand the dynamics of neuron networks in the cerebral cortex. By acquiring a better understanding of neuronal communication, they seek to more fully comprehend the enormous
complexity of the body as a whole. This approach is essential to understand the interactions between neurons involved in generating seizures and anticipate possible side effects of new drugs. The group of Eric Leguern seeks to identify the genes involved in inherited epilepsies that run in families, in parallel with work to «dissect» electrical signals in the brain. Their approach recently identifi ed a new gene called LGI1, which does not function correctly in some families of epileptic patients.
Finally, one of the major problems with epilepsy is that sufferers have to constantly take medications with annoying side effects, while the seizure may only come once a month. Furthermore, some people carry genes that are totally intolerant to drugs. Researchers and doctors working with Professor Michel Baulac therefore develop advanced electroencephalography analysis systems, in an attempt to «read» the warning signals of a
seizure several minutes before it occurs.