Brain tumors, both primary and metastatic, are vigorously destructive forms of cancer, with about 210,000 cases reported annually in the United States. The most common treatment is whole brain irradiation (IR), which unfortunately is complicated by hippocampal damage that impairs the normal physiologic process of hippocampal neurogenesis. Reduction in hippocampal neurogenesis leads to neuropsychiatric complications, including impaired spatial memory and problem-solving ability, as well as emotional dysregulation and depression. Indeed, approximately 40-50% of patients display progressive learning and memory deficits after whole brain IR. P7C3, an aminopropyl carbazole that is the prototypical member of a novel class of neuroprotective agents, increases the net magnitude of hippocampal neurogenesis in the dentate gyrus by protecting newborn neurons from cell death, and has been shown to have antidepressant and cognitive benefits in a variety of preclinical models by virtue of this property. We thus hypothesized that P7C3 compounds will protect mice from the cognitive and depressive-like deficits elicited by whole brain IR.