Behavioral, electrophysiological, and histopathological consequences of mild fluid-percussion injury in the rat.

Metabolic dysfunction in the relay nuclei of the rat vibrissa circuit follows traumatic brain injury (TBI). This study examined the effects of mild (1.4-1.5 atm) parasagittal fluid-percussion injury on the electrophysiology of this circuit. TBI caused significant reductions in slope and increases in latency of vibrissa-evoked field potentials 3 days after injury. Assessment of open-field swimming revealed an increase in thigmotaxis 2 days after injury. TBI caused mild selective cortical damage and limited axonal swelling at the injury site. Thus mild injury disrupts somatosensory electrophysiology and exploratory behavior.