BRAIN - In rats, diffuse brain damage can occur with no signs of 'concussion'

A standard experimental model of concussion in rats causes substantial brain damage—but no behavioral changes comparable to those seen in patients with concussion, reports a study in the April issue of Neurosurgery, official journal of the Congress of Neurological Surgeons ...

http://medicalxpress.com/news/2014-03-rats-diffuse-brain-concussion.ht