The purpose of this study is to test the safety and feasibility of recording brain activity within and around high-grade glioma tumors at the time of surgery. A small biopsy will be taken at the sites of the recordings.

High-grade gliomas are incurable primary brain tumors. Recent data support that glioma cells can integrate within neuronal circuits. Glioma cells and neurons communicate via electrical impulses and chemically, through neurotransmitters. This crosstalk has been shown to promote glioma cell migration and invasion in preclinical models. However, the nature of the electrical activity and underlying molecular mechanisms are poorly understood. The long-term goal of this study is to determine the impact of high electrical activity and pattern of activity on tumor invasion, and mechanistic basis of its regulation and functional consequences. This phase I safety and feasibility study is being proposed as a first step toward dissecting the connection between electrical activity and glioma behavior. The goal is to determine the safety and feasibility of recording electrical activity in the tumor-neuron interface using technologies that are already being used clinically for participants undergoing brain surgery.

Inclusion Criteria:

• Participants who have the appearance of high-grade glioma (HGG, WHO Grade 3 and 4, including GBM) on MR imaging are allowed to consent and will undergo the procedure if the frozen is consistent with HGG

OR

• Participants with a history of histologically-confirmed diagnosis of high- grade glioma that are undergoing resection of a recurrent/progressive tumor that is likely recurrent/progressive high- grade glioma as identified on preoperative MR imaging

• Age ≥ 18 years old

• Volumetric MRI within 1 month prior to surgery

• Karnofsky performance status of 60 or higher

• The participant (or legally acceptable representative if applicable) provides written informed consent for the trial.

• Participants must be considered appropriate neurosurgical candidates with the following screening/baseline laboratory values within 1 month prior to surgery:

  • Absolute neutrophil count ≥ 1500/µL
  • Platelets ≥ 100 000/µL
  • International normalized ratio (INR) OR prothrombin time (PT) Activated partial thromboplastin time (aPTT) ≤1.5 × Upper limit of normal (ULN) unless participant is receiving anticoagulant therapy as long as PT or aPTT is within therapeutic range of intended use of anticoagulants
  • Urine or Serum Pregnancy Test = Negative (Not applicable to participants with bilateral oophorectomy and/or hysterectomy or to those participants who are postmenopausal).

Exclusion Criteria:

• Severe co-morbidity that would confer excess risk of surgery as determined by the treating physician.
• Any other major medical illnesses or psychiatric impairments that in the investigator's opinion will prevent administration or completion of protocol therapy.
• Is pregnant
• Coagulopathy or platelet dysfunction that increases the risk of intra and postoperative hemorrhage
• Tumor location requiring DE placement/biopsy in eloquent or critical region of the brain (e.g. primary motor and sensory cortices, speech and vision centers, thalamus, basal ganglia, cerebellum, brain stem) as deemed by the neurosurgeon designing the surgical plan

Aggregate data will be shared, while individual data will not need to be shared.