What Happens in the Brain During Epilepsy?

Epilepsy is a neurological condition characterised by recurrent seizures caused by abnormal electrical activity in the brain. To understand epilepsy fully, it is important to know what happens inside the brain when seizures occur and how these changes affect the body and mind. This article explores the brain mechanisms involved in epilepsy, explaining the abnormal processes that lead to seizures and their effects, based on trusted UK health information.

Normal Brain Function and Electrical Activity

The brain communicates through a complex network of nerve cells called neurons. These neurons transmit electrical signals to each other, allowing the brain to control thoughts, movements, sensations, and bodily functions. Under normal conditions, this electrical activity is well-regulated and balanced, maintaining smooth brain function.

Abnormal Electrical Activity in Epilepsy

In epilepsy, this balance is disrupted. Groups of neurons become hyperexcitable and fire electrical signals excessively and synchronously. This abnormal surge overwhelms the brain’s normal signalling, leading to seizures. The excessive electrical activity may remain confined to a small area of the brain or spread across larger regions, influencing the type and severity of the seizure.

Seizure Origination and Spread

Seizures typically start in a specific part of the brain called the seizure focus. This area may have structural abnormalities, scar tissue, or genetic changes that make neurons more likely to misfire. From this focus, abnormal electrical activity can spread to adjacent brain regions or involve both hemispheres, resulting in generalised seizures that affect consciousness and body movements.

Chemical Imbalances and Neurotransmitters

The brain’s electrical activity is controlled by chemicals called neurotransmitters, which regulate excitatory and inhibitory signals between neurons. In epilepsy, an imbalance occurs where excitatory neurotransmitters like glutamate become overactive, or inhibitory neurotransmitters such as gamma-aminobutyric acid (GABA) are less effective. This imbalance increases the likelihood of seizures by lowering the brain’s threshold for abnormal firing.

Structural Brain Changes

In some people with epilepsy, structural changes in the brain contribute to seizure activity. These changes can include scarring from injury or infections, brain tumours, or developmental abnormalities. Such alterations disrupt normal electrical pathways and create areas prone to seizures.

Impact on Brain Function During Seizures

During a seizure, the abnormal electrical activity interferes with normal brain functions. Depending on the area affected, this can cause a range of symptoms such as loss of consciousness, uncontrolled movements, sensory disturbances, or changes in behaviour. The disruption usually lasts from a few seconds to minutes, after which brain activity gradually returns to normal.

Brain Recovery After Seizures

Following a seizure, the brain enters a recovery phase where electrical activity stabilises. Some people experience a postictal state characterised by confusion, tiredness, or headache. The brain’s ability to recover varies, influenced by seizure type, frequency, and overall brain health.

Why Some Brains Are More Susceptible

Certain genetic mutations, injuries, or illnesses make some brains more susceptible to developing epilepsy. These factors can alter neuron function, neurotransmitter balance, or brain structure, creating a predisposition to seizures. However, not all individuals with these factors develop epilepsy, highlighting the complexity of the condition.

How Treatments Affect Brain Activity

Anti-epileptic medications work by restoring balance in brain electrical activity. They often enhance inhibitory neurotransmitters or reduce excitatory signals, raising the seizure threshold. Other treatments like surgery aim to remove or isolate seizure foci to prevent the spread of abnormal activity.

Final Thought

Epilepsy involves abnormal, excessive electrical activity in the brain caused by chemical imbalances, structural changes, or genetic factors. This disruption leads to seizures that affect brain function temporarily. Understanding what happens in the brain during epilepsy helps guide treatment and supports better management of the condition.