Inclusion Criteria:  Pathologically confirmed diagnosis of high grade glioma (grade III or IV) or WHO grade II glioma, IDH wildtype (molecular glioblastoma multiforme [GBM]). ≥18 years of age. ECOG performance status of 0 to 3 Anticipated to receive 6 weeks of chemoradiation  Exclusion Criteria:  Does not speak or read English Unable to participate in cognitive testing due to aphasia or other severe cognitive impairment as determined by the PI, or Dr. Cummings or her designee. Unable to give informed consent Past medical history of any kind of dementia or diagnosed with mild cognitive impairment prior to diagnosis with their brain tumor Unable to safely fast for 8 hours prior to bloodwork or 6 hours prior to PET scan  Currently taking cognition-enhancing medications including:  Donepezil Memantine Armodafinil Methylphenidate Pregnant or nursing mothers. Patients taking blood thinners will be excluded from the optional Lumbar Puncture only, they are eligible for participation in the main study-provided they meet inclusion/exclusion criteria