In the long term, drugs that can delete painful memories could also be used routinely. "We are now looking 20-25 years ahead," said Prof Robbins. "Very basic science is showing that it is possible to call up a memory, knock it on the head and produce selective amnesia."While certain drugs can impair or enhance performance on certain types of memory tasks (and, by implication, interfere with or facilitate the function performed by certain brain systems), there is no such thing as a memory that can be "called up," like pulling a photograph out of an album. What we perceive to be a "memory" is actually a reconstruction, dynamic and unstable, based on relatively impoverished information that some in the business call "contextual cues." The "memory" will not be the same on every recollection, and we have no reason to believe that different recollections of an event even use the same neurons each time, although the same brain areas will be recruited (but to a greater or lesser extent) each time. The idea that we could "kill" a single "memory" represents such a gross misunderstanding of memory processes that I can't attribute it to the respected Professor Robbins.
I have, on occasion, had to describe my research results to the media. I consider this one of my social responsibilities as a scientist, especially a scientist that accepts taxpayer-supported funding. However, I always require that the reporter give me a draft of the article for comment before it appears in print, to make sure that potentially complex theoretical ideas have not been misrepresented, as they have in this article. It often makes for less titillating reading, unfortunately. My stuff rarely makes the newspapers, and maybe my unwillingness to let the reporter's imagination run wild is why.
4 comments:
(rolling eyes)
Somebody enjoyed Eternal Sunshine of the Spotless Mind a little too much.
Not entirely. The theory that memory reads are destructive has some supporting research. We do know that it is possible to block the formation of memories by blocking production of a particular necessary protein.
If memory reads in the human brain are in fact destructive, then to force a memory read while under the influence of the memory write blocker, would dispose of the memory.
I'll go look for the human research now. Here is one of the mouse studies.
http://www.learnmem.org/cgi/content/full/7/5/333
Blocking the formation of a particular memory (or kind of memory) is well known, even in human memory. That is not the same thing as "knocking out" the memory for a particular event (a particular episodic trace). Memory of an event is a process, not something that is "stored" somewhere, or the firing of a particular set of neurons.
OK, I still agree with myself. I read Vianna et al., and this study is concerned with the acquisition (or not) of memory for a novel environment with pre- and post-training infusions of drugs that interfere with the formation of long-term memories.
As I said above, interfering with the formation of novel memories or destroying a whole type of memory system is not the claim that the reporter attributes to Robbins in the original story.
There is no way to selectively kill one established episodic memory trace. You can wipe out a whole class of them by various sorts of unfortunate brain damage, and there are drugs that will induce amnesia for events that occur while under the influence of that drug, but you can't remove, say, the memory of when you threw the rock through Mr. Johnson's window once that memory is established. Not without wiping out a lot of other memories that you probably want to keep.
The Vianna et al. study would be relevant to this issue if they had showed that when rats were exposed to two novel environments, administering any of these drugs selectively impaired the memory for one of those environments but not the other.
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