Morris water maze deficits in rats following traumatic brain injury: lateral controlled cortical impact.
This experiment utilized a laterally placed controlled cortical impact model of traumatic brain injury (TBI) to assess changes on spatial learning and memory in the Morris water maze (MWM). Adult rats were subjected to one of two different levels of cortical injury, mild (1 mm) or moderate (2 mm) deformation, and subsequently tested for their ability to learn (acquisition) or remember (retention) a spatial task, 7 or 14 days after injury. Results revealed an injury-dependent deficit for experimental animals compared to sham-operated controls. Not only did the TBI result in longer escape latencies, but also significant deficits in search time and relative target visits. Although the moderately injured animals demonstrated significant histopathology in the cortex and hippocampus, mildly injured subjects demonstrated no obvious tissue destruction, but did manifest significant behavioral change. These results demonstrate that a laterally placed controlled cortical impact is capable of producing significant cognitive deficits on both acquisition and retention paradigms utilizing the MWM.
Scheff
S W
SW
Sanders-Brown Center on Aging and Department of Psychology, University of Kentucky, Lexington 40536-0230, USA.
Baldwin
S A
SA
Brown
R W
RW
Kraemer
P J
PJ
D000704:Analysis of Variance; D000818:Animals; D001930:Brain Injuries / Q000473:pathology / Q000503:physiopathology* / Q000523:psychology; D016022:Case-Control Studies; D002540:Cerebral Cortex / Q000473:pathology; D003072:Cognition Disorders / Q000209:etiology / Q000473:pathology / Q000503:physiopathology*; D004195:Disease Models, Animal; D004924:Escape Reaction / Q000502:physiology; D005106:Exploratory Behavior / Q000502:physiology; D006624:Hippocampus / Q000473:pathology; D008137:Longitudinal Studies; D008297:Male; D018782:Maze Learning; D009949:Orientation / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D011930:Reaction Time; D012153:Retention, Psychology; D016037:Single-Blind Method; D013550:Swimming / Q000502:physiology; D015599:Trauma Severity Indices