A 6-year-old girl is brought to the clinic by her parents due to concerns about frequent episodes of staring spells. Her teacher reports that she sometimes appears to be daydreaming and does not respond when called on in class. The episodes last for about 10 seconds, occur multiple times a day, and immediately resolve without confusion. Her physical exam and neurological exam are normal. During evaluation, she is asked to hyperventilate for a few minutes, and an episode is provoked. Which of the following findings is most likely to be seen on her EEG?
