Brain Waves: Riding the Ups and Downs of Epilepsy

March, 22nd, 2023 by Marcio Furtado

 Epilepsy is a neurological disorder characterized by recurrent seizures, which are sudden and uncontrolled electrical discharges in the brain. Seizures can cause a range of symptoms, including convulsions, temporary confusion, loss of consciousness, and changes in behavior or mood.

 The causes of epilepsy are diverse, and can include genetic factors, brain injuries, infections, tumors, and other medical conditions. In many cases, the cause of epilepsy is unknown.

 According to the Centers for Disease Control and Prevention (CDC), epilepsy affects about 1.2% of the U.S. population, or about 3.4 million people. The prevalence of epilepsy varies by age group, with higher rates in young children and older adults. In children under age 15, epilepsy affects about 0.6% of the population, while in adults over age 65, it affects about 1.6%.

 Overall, epilepsy is slightly more common in males than females, and is more prevalent among certain racial and ethnic groups, including non-Hispanic Black and Hispanic individuals. Treatment for epilepsy typically involves medication to manage seizures, and in some cases, surgery or other therapies may be recommended.

 Epilepsy can involve various brain areas depending on the type and cause of the seizures. However, some brain regions are more commonly associated with epilepsy than others. These include:

1.      Temporal lobes: The most common form of epilepsy is temporal lobe epilepsy, which originates in the temporal lobes of the brain. The temporal lobes are involved in memory, language, and emotion processing.

2.      Frontal lobes: Seizures that originate in the frontal lobes can cause a range of symptoms, including motor movements, vocalizations, and changes in behavior.

3.      Parietal lobes: Seizures that arise in the parietal lobes can cause sensory symptoms, such as tingling, numbness, or changes in body perception.

4.      Occipital lobes: Seizures that start in the occipital lobes can cause visual disturbances, such as flashes of light, blurring, or blindness.

5.      Thalamus: The thalamus is a key relay station in the brain that helps to process sensory information. Seizures that originate in the thalamus can cause a range of sensory symptoms, including pain, temperature changes, and abnormal perceptions.

6.      Brainstem: Seizures that start in the brainstem can cause a range of symptoms, including changes in heart rate, breathing, and consciousness.

 It's important to note that epilepsy can involve multiple brain areas and can vary widely from person to person. A neurologist or epilepsy specialist can help to diagnose and treat epilepsy by evaluating a person's symptoms and performing diagnostic tests, such as EEG and MRI scans.

Animal models are important tools for studying epilepsy and developing new treatments. The following are some of the most commonly used animal models of epilepsy:

1.      Pentylenetetrazol (PTZ) induced seizures: This model involves the administration of PTZ, a GABA antagonist, to induce seizures in animals. The seizures generated by PTZ are similar to those seen in human temporal lobe epilepsy.

2.      Kainic acid (KA) induced seizures: This model involves the administration of KA, a glutamate agonist, to induce seizures in animals. The seizures generated by KA are similar to those seen in human mesial temporal lobe epilepsy.

3.      Pilocarpine induced seizures: This model involves the administration of pilocarpine, a muscarinic agonist, to induce seizures in animals. The seizures generated by pilocarpine are similar to those seen in human temporal lobe epilepsy.

4.      Auditory stimulation induced seizures: This model involves exposing animals to repeated auditory stimuli to induce seizures. The seizures generated by auditory stimulation are similar to those seen in human reflex epilepsy.

5.      Chemical kindling: This model involves repeated administration of sub-convulsive doses of a chemical, such as PTZ or KA, until seizures are elicited. Chemical kindling can produce a chronic epilepsy state that is similar to human temporal lobe epilepsy.

6.      Genetic models: This includes animals with mutations or knockouts of specific genes associated with epilepsy, such as the sodium channel gene Scn1a or the GABA receptor gene Gabrg2. These models can help researchers understand the underlying genetic causes of epilepsy and develop new treatments.

Each of these models has its own strengths and limitations, and the choice of model depends on the specific research question being addressed.