A 27-year-old woman with a 15-year history of drug-resistant focal epilepsy undergoes high-resolution 3-Tesla MRI brain with dedicated epilepsy protocol. She presents with a 15-year history of stereotyped focal impaired-awareness seizures with epigastric aura and oral automatisms, preceded by febrile status epilepticus at age 3. Long-term video-EEG monitoring shows left anterior temporal theta onset. The structure marked **A** in the MRI demonstrates marked volume loss with preserved contralateral anatomy. Which of the following best describes the pathophysiological significance of this finding in the context of mesial temporal lobe epilepsy?