Long-term cognitive impairment without diffuse axonal injury following repetitive mild traumatic brain injury in rats.

•As a risk factor, repetitive mild TBI provides a valid model of dementia in rats.•Rats were subjected to either single severe, single mild or repetitive mild TBI.•Single mTBI did not result in any behavioral abnormalities.•rmTBI caused severe chronic memory deficits in NOR and MWM.•Unlike sTBI, rmTBI exerted deficits without axonal injury or increased GFAP levels.