What does a spike on the EEG between seizures say about the brain? · Grey Matter

An interictal spike, a sharp wave of 20 to 70 ms standing out from the background, shows that a patch of cortex can make many neurons fire almost at once, the same synchrony a seizure is built from, while inhibition still cuts it short.

What does a spike on the EEG between seizures say about the brain?

An interictal spike, a sharp wave of 20 to 70 ms standing out from the background, shows that a patch of cortex can make many neurons fire almost at once, the same synchrony a seizure is built from, while inhibition still cuts it short. It supports a diagnosis of epilepsy and its position on the scalp points to where focal seizures may begin, though it causes no symptom by itself. Its absence on a single recording proves little, and long recordings from implanted devices show spike rates rising and falling over cycles of weeks, with seizures more likely near the peaks.