REDUCED SENSORIMOTOR REACTIVITY FOLLOWING TRAUMATIC BRAIN INJURY IN RATS

The present study examined sensorimotor reactivity in rats following t raumatic brain injury (TBI). Moderate injury was induced with midline fluid percussion in some of the rats. Others received identical surger y, but were not injured (sham-injured rats), or received neither surge ry nor injury (naive rats). All rats were evaluated in acoustic and/or tactile startle procedures. At 8 days post-injury, the sensorimotor r eactivity of TBI rats to acoustic stimuli was severely reduced compare d to that of sham-injured rats. This TBI-induced deficit was enduring (> 30 days). In a separate experiment, greater sensorimotor reactivity was observed with tactile (vs. acoustic) stimulation in both TBI and naive rats, although startle amplitudes for the TBI rats were lower th an control levels for both types of stimuli. These results suggest tha t sensorimotor reactivity is altered by TBI and that the startle proce dure is a promising method for investigation of information processing alterations following TBI.