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Drug Selectively Removes Rats' Memory
rednuhter writes "Nature online is reporting scientists have used drugs to selectively remove one memory while not affecting another.
Musical tones were played to the rats and at the same time the subjects were given a mild electric shock. Half the study group were given the drug (not approved for use in humans) and then the experiment was repeated with a new tone. The following day the rats that had not been given the treatment were afraid of both tones while the treated half were only afraid of the second tone: the memory of fear of the first had been erased."
The objective results are pretty inarguable, but the implication that the reason that the rats didn't fear the note they heard while drugged is that they had completely forgotten about it seems tenuous. The rats could just as easily become accustomed to the note, develop a different association with that note (like being drugged), or become unafraid of it for some other related reason.
The article supports the claim by saying the brain activity is different, but it seems that more complicated experiments would need to be done before it could really be claimed that memories could be wiped this way.
A drug that selectively erases memories would be very oopen to misuse. I believe we should immediately institute proper measures to prevent our police, governments, and military forces from..
....what was I saying?
..what's that? A glass of orange juice? My favorite! Thank you, that's very kind.
Now then.. *gulp*
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Only for those with the drug. And, tellingly, they were immune to the first tone and not the second (repeated, but different) tone.
They still responded to the second tone (post-drug) that was paired with the shock.
Very limited super powers, as they still responded to the second tone. I know this is /. but you could at least read the summary completely. ;)
Ben Hocking
Need a professional organizer?
First, according to article, the rats were first "trained" to fear both tones. Thus, you don't have to administer the drug before the stimulus has been conditioned to produce a fear response and you don't have to administer the drug during the fear conditioning. Therefore, this is not a proactive treatment, but a retroactive one. You would not use this drug to train a ruthless, emotionless army. The article says nothing about the drug preventing or blocking the future association of neutral stimuli with a fear response provoked by a stressful stimuli.
Second, the drug is administered and then the "conditioned" stimuli is introduced while the subjects are under the influence of the drug. Later when the drugged subjects were tested, they showed no fear response for the stimuli they rehearsed while drugged. And the fear response was only removed for the stimuli that was introduced during the drugging, leaving other conditioned responses intact.
Now, as is often the case with news articles on research, the article's claim is misleading. This research does not actually imply that you can selectively remove a fearful memory. The research design only targetted conditioned, associative responses, which are a subset of the larger category of memories. There is memory for the event in itself and there is memory for associating the event as the cause of some unpleasant effect. But all the research shows is that the the link between the conditioned stimuli and the fear response has been broken. There may still be "episodic" memory for the original stimuli and the unpleasant. Unfortunately, we cannot interview the rats and ask them if they remember the details of their conditioning prior to the drugging.
On to humans... if the drug does not remove the "episodic" memory of the "traumatic" stimulus, it might not be all that advantageous to remove the "fear" response in the first place. Imagine what it might be like to feel NOTHING when you are recalling a mortar round tearing your friend into pieces beside you. That might be a lot more sinister than feeling stressed. But what you do in the case of PTSD is administer the drug and then play sounds like cars back firing, ballons popping, and etc. That way you help the patient to unlearn the "stress response" for neutral, non-related stimuli without affecting the original memory and association.
It'd make war crime tribunals a whole lot easier to deal with.