Figure 1.  Concepts underlying epileptogenesis in TLE from the past and present. (A) Past concepts. 1. General timeline. Epileptogenesis had been suggested to occur in 3 phases,1 the first typically occurring in early life and involving a brain insult or injury. A “silent” period follows the insult or injury and occurs before the first convulsive seizure. The first convulsive seizure is the start of the phase called chronic epilepsy or simply “epilepsy”. 2. Underlying events. The brain insult is typically an acquired event such as brain injury or infection, with examples listed. During the silent period, MTS develops and ultimately recurrent spontaneous seizures (defining chronic epilepsy). (B) Present concepts. 1. The general timeline is now considered with more appreciation for the role of genes. Therefore, after an initial insult or after altered genes exert effects (eg, on neurodevelopment), there is a progressive worsening of increased excitability (epileptogenesis). Spontaneous seizures can occur early or later in this progressive course of events. After 2 unprovoked seizures the term epilepsy is used39 2. Underlying events. Initial events include those that are not acquired. There is a rapid start in the reaction of the brain to the insult and ultimately a complex series of events unfolds, with some reactions leading to further changes. TMTS is one of the events that stimulates changes but others can also. Spontaneous recurrent seizures may occur before the brain stops changing.