 Use of Intracerebral Microdialysis to Quantitate Markers of Neuroinflammation Previous studies have demonstrated that patients with increased inflammatory cytokines from medical illnesses exhibit increased rates of depression. Both chronic and acutely elevated levels of inflammatory cytokines can result in the development of neuropsychiatric dysfunction, including cognitive slowing, inattention, or depression. Specifically, Dowlati et al concluded from a meta-analytic study that a small proportion of patients with idiopathic major depressive disorder exhibited increased serum cytokine levels. Thus, the investigators propose to quantitate markers of neuroinflammation and oxidative stress in collected dialysate, with the hypothesis that variance in these levels may correlate with affective andor cognitive dysfunction. 