- Determine the feasibility of using a microdialysis catheter with a high cut-off membrane to perform neuropharmacodynamics (nPD) assessment of targeted therapy with a mammalian target of rapamycin (mTOR) inhibitor, where nPD is defined as changes in intracerebral levels of vascular endothelial growth factor (VEGF), interleukin-1ß (IL-1ß), and other cytokines.