Experimental time line.

<p>Two-month-old C57BL/6 mice received whole body irradiation (4 Gy) and immediately after (∼15 min) received either controlled cortical contusion injury or sham craniotomy. Two weeks after injury animals were injected daily for 5 days with BrdU (100 mg/kg). DFMO was made available in the drinking water immediately upon recovery from surgery and for a total of 42 days and was stopped two days before cognitive testing in the Morris water maze. Animals were euthanized 30 minute after the last probe trial.