In focal or partial epilepsy, seizures initially affect only part of the brain. This is in contrast with generalized seizures that involve the entire cerebral cortex. Focal epilepsy may affect just one hemisphere or part of the cortical lobe. Consequently, symptoms will depend on where the seizure focus is located.
In a rare condition affecting 2% to 7% of children with focal epilepsy, the main and often only symptom consists of visual auras, where flashes of light or static small multicolored circular patterns in the periphery of the visual fields become larger, multiply, and move horizontally to the other side.
Based on this description, which part of the brain is most likely affected by the seizure?