This research program is designed to add to our understanding of the neurobiological basis of memory. Dr. Jarrard is examining the types of memory deficit which occur when a very specific part of the brain sustains damage. While there is considerable evidence that this region of the brain, the hippocampus, is important in the formation of memories, the exact nature of this involvement is not yet known. The long history of the search for the memory trace, or "engram," is filled with attempts to attach functional relevance to many different parts of the brain. Unfortunately, most of this previous work has been performed using mechanical or electrical lesions, that is, a rather imprecise part of the brain had been damaged. Dr. Jarrard has developed a new technique which uses specific neurotoxins for selectively depleting nerve cells within the hippocampus, but which spares nerve fibers. The result of this procedure is that the overall damage to the hippocampus is markedly reduced. As a consequence, functional specificity can be attributed to groups of nerve cells within this brain area. The knowledge gained from these experiments provides us with a better understanding of how the hippocampus is involved in learning and memory. At the human level, the hippocampus is often found to be damaged in patients with Alzheimer's Disease, those who have suffered from stroke, in some types of epilepsy, in perinatal asphyxia, and in postoperative complications resulting from cardiothoracic surgery. As a result of this hippocampal damage, there is a problem in learning and remembering new information. The research being conducted by Dr. Jarrard is not only adding to what is known about how the brain controls learning and memory, but is also adding to our understanding of a part of the brain often associated with memory problems in humans.
