Prospective, double-blind, randomized-controlled study for pediatric cases scheduled for brain tumor excision with the aid of electrocorticography (ECOG). Intraoperative ECOG has been used in an effort to localize the site of epileptogenicity through the demonstration of Interictal Epileptiform Discharges (IED) persistence, frequency, and distribution. During ECOG, pharmaco-activation may be required in order to activate Interictal Epileptiform Abnormalities (IEAs). Frequency of IEAs will be measured for each drug.

The effects of anesthetic agents on intraoperative ECOG, as we assume that fentanyl will be superior to ketamine.

Brain tumors can be responsible for epilepsy refractory to medical therapy. These are typically slow-growing tumors, and surgery aims to cure the patient's seizure disorder. One of the main uses of electrocorticography is mapping the cortical regions associated with epileptiform activity. This information is used to plan resection boundaries. Electroencephalography (EEG) electrodes are placed directly on the cortical surface, and epileptiform activity is identified, and this can guide the extent of resection. This technique is referred to as intraoperative electrocorticography (IOECOG).

IOECOG has been used to localize the site of epileptogenicity through the demonstration of Interictal Epileptiform Discharges (IED) persistence, frequency, and distribution. As the intraoperative time is short, clinical seizures are usually not captured by ECOG, but the presence and location of IEAs can be used to localize the epileptogenic focus and guide the resection.

During ECOG, pharma coactivation may be required to activate IEAs. Fentanyl and ketamine can be used for this

Inclusion Criteria:

• Age (2-18) Years scheduled for brain tumor excision with aid of ECOG
• ASA physical status (II-III).
• Patient undergoing brain surgery with epileptic focus.

Exclusion Criteria:

• guardian refusal.
• Patients with hypertension, ischemic heart disease, arrhythmia, or respiratory or renal dysfunction.