Acute Neurobehavioral Assessments of the Closed-Head Mild Traumatic Brain Injury (MTBI) Rat Model

After inducing a mild traumatic brain injury in an anesthetized rat, position it on its back inside a clean cage. Record the duration from when the rat is anesthetized to when it regains the righting reflex. Also record the time it takes for the rat to exhibit its first seeking behavior from the moment of anesthesia.

Next place the rat in the center of a circular apparatus with an exit. Measure and record the time it takes for the rat to exit the circle. Then place the rat successively on three beams of varying length each for a duration of one minute.

Score the rat on a scale of zero to six, depending on their performance on the beam. mTBI rats exhibited a significantly prolonged recovery from unconsciousness. The seeking behavior increased significantly in the mTBI group during the recovery period.

Also, the mTBI rats took longer to exit the circle compared to sham rats. The beam balance test showed a significant injury effect in wide beam tasks indicating balance impairment in mTBI rats 10 minutes post impact. The 2 and 1.5 centimeter wide beams effectively differentiated between sham and mTBI groups in three independent experiments.