MadSci Network: NeuroScience |
This is a very interesting and challenging question. Let’s start at the beginning and talk about the hippocampus. You are correct in saying that is involved in human memory (and probably that of animals as well). It seems to be an integral part of the process of forming new memories such as learning facts or information (sometimes called explicit memory). However, its role in other types of memories such as learning skills and habits or motor memory is less secure. In fact, most scientists are leaning towards the idea of having multiple memory systems as opposed to having just one. In a similar vein, scientists often talk about the hippocampus as being part of a larger memory system or systems that include other parts of the brain such as the amygdala. At the very least, it is probably more accurate use the label of a hippocampal system as opposed to simply the hippocampus. From there, your question becomes even more difficult to answer because you seem to be equating memory with personality (which is a giant leap). An important issue here is that most psychologists have problems simply agreeing on the definition for personality. For example, some psychologists (radical behaviorists) argue against the idea that a personality actually exists. Even those who accept the notion of personality as real see it primarily as a construct (an abstract idea) rather than something tangible that you could literally see and hold. My own bias is that our personality is much more than simply the total integration of our memories, but I may be wrong. In support of your idea, we do know that persons suffering from Alzheimer’s Disease (which, by the way, involves the hippocampus) undergo a personality change. However, it is fairly clear that our personality (whatever it is) is not limited to the hippocampus alone. Regarding the last part of your question, to my knowledge there have not been any studies that show personality changes or switches from hippocampal fluid transfers. I doubt that any such studies have been done (at least with humans). Such studies more than likely would not be considered to be ethical. In addition, You seem to be assuming an extreme reductionistic approach here. Scientists who favor more of a holistic approach might question whether we would be able to transfer a personality from one person to another even if we were able to (or allowed) to make complete brain transplants. In any event, we really don’t have the complete answers to your question yet. For more information look up memory and/or hippocampus on the Internet. An interesting college level book in this area is called “Looking for Memory”, by Daniel Schacter (Basic Books, 1996).
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