Mechanisms of anterograde and retrograde memory impairment following experimental traumatic brain injury

• Published in: Brain research Vol. 1213; pp. 69 - 77
• Main Authors: Whiting, Mark D, Hamm, Robert J
• Format: Journal Article
• Language: English
• Published: London Elsevier B.V 05.06.2008; Amsterdam Elsevier; New York, NY
• Subjects: Adult and adolescent clinical studies; Amnesia; Amnesia, Anterograde - etiology; Amnesia, Retrograde - etiology; Animals; Biological and medical sciences; Brain Injuries - complications; Brain injury; Disease Models, Animal; Injuries of the nervous system and the skull. Diseases due to physical agents; Male; Medical sciences; Memory impairment; Multivariate Analysis; Neurology; Organic mental disorders. Neuropsychology; Psychology. Psychoanalysis. Psychiatry; Psychopathology. Psychiatry; Rat; Rats; Rats, Sprague-Dawley; Retrieval; Time Factors; Traumas. Diseases due to physical agents; Retrieval; Memory impairment; Amnesia; Rat; Brain injury; Memory retrieval; Memory disorder; Nervous system diseases; Cognitive disorder; Memory; Rodentia; Cerebral disorder; Vertebrata; Mammalia; Animal; Anterograde; Central nervous system disease; Head trauma; Neurological disorder
• ISSN: 0006-8993; 1872-6240
• DOI: 10.1016/j.brainres.2008.01.107

Abstract Memory impairment is common following traumatic brain injury. However, the specific processes underlying the impairments remain unknown. Traumatic brain injury may interfere with several of the stages of the learning and memory process. In two separate experiments, we examined the specific nature of both anterograde and retrograde memory dysfunction following fluid percussion brain injury in rats. In Experiment 1, we examined the retention of spatial memory in the MWM after equating initial learning between sham and injured animals. Animals were trained to criterion and then tested for retention 4, 8, or 24 h post-training. Although injured animals displayed deficits in task acquisition, retention performance was not significantly different between groups. In Experiment 2, we examined the effects of injury on the retention of retrograde spatial memories in the MWM. Animals were injured either 1 or 14 days post-training and then received retention probe trials followed by a reminding procedure and second probe trial 14 days post-injury. All injured animals displayed retention deficits in the probe trials 14 days post-injury. However, after the reminding procedure, injured animals displayed sham-level performance during the second probe trial. The results of these experiments suggest that with anterograde memory impairment induced by traumatic brain injury, the primary deficit lies in task acquisition, not the retention of information within long-term memory. Retrograde memory impairment following injury appears to be mediated primarily by deficits in memory retrieval.