Affiliations: Traumatic Brain Injury Laboratory, Department of
Neurosurgery, The University of Pennsylvania, Philadelphia, PA, USA | Biobehavioral Nursing and Health Systems, The
University of Washington, Seattle, WA, USA | Veteran's Administration Medical Center, Philadelphia,
PA, USA | Department of Neurosurgery, Uppsala University
Hospital, Uppsala, Sweden
Note: [] Corresponding author: Hilaire J. Thompson, PhD, RN,
Biobehavioral Nursing & Health Systems, Box 357266, Seattle, WA 98195-7266,
USA. Tel.: +1 206 616 5641; Fax: +1 206 543 4771; E-mail:
[email protected]
Abstract: Purpose: As deficits in memory and cognition are commonly observed
in survivors of traumatic brain injury (TBI), causing reduced quality of life
for the patient, a major goal in experimental TBI research is to identify and
evaluate cognitive dysfunction. The present study assessed the applicability of
the serial Morris water maze (MWM) test to determine cognitive function
following experimental TBI in the same group of rats which is particularly
important for long-term studies and increasingly valuable for the evaluation of
novel treatment strategies. Methods: Male Sprague-Dawley rats (n=27) were anesthetized
and subjected to either sham injury (n=9) or lateral fluid percussion (FP)
brain injury of moderate severity (n=18). At 4 weeks post-injury, animals
were trained in a water maze over 3 days (acquisition/learning phase) to find a
submerged platform. At 8 weeks post-injury the hidden platform was then moved
to the opposite quadrant, and animals were trained to find the new position of
the platform over 3 days. Forty-eight hours later, animals were tested for
memory retention in a probe trial in which the platform was not present. Results: Brain-injured animals had significant learning
impairment (p<0.0001), shifted-learning impairment (p<0.001) and
memory retention deficits (p<0.01) in comparison to their sham-injured
counterparts over the 8 week testing period. Swim speed and distance were not
significantly altered by brain injury at any time point. Conclusion: The validation of this testing paradigm using a
clinically relevant experimental brain injury model is an important addition to
behavioral outcome testing.
Keywords: Head injury, water maze, shift learning, reversal learning, multiple time points
