Fig. 1.

Selected proposed mechanisms of radiation-induced neurocognitive dysfunction. (A) Pro-inflammatory changes following radiotherapy result in an increase in the numbers of microglia which produce TNF-α and IL-6. This contributes to an ongoing inflammatory state and alteration in the microenvironment, which preferentially drive differentiation of neural precursors to an astrocytic lineage. (B) Radiation disrupts the vascular niche of the neural precursors and additionally leads to ischemia and toxic neuroexcitation among mature neurons. (C) Radiation exposure reduces the number of dendritic spines on mature neurons, which in turn disrupts synaptic efficiency.