Prick and forget
Even the electrical activity of brain regions at all stages of memorization has been studied; in total, four of them are distinguished in the work of memory: perception, consolidation, storage and reproduction.
In the first, the sensory organs and the corresponding areas of the brain are most active, in the second – the hippocampus, and the last two are the lot of the cerebral cortex, in which numerous neural networks are formed that directly "store" information. It is believed that it is thanks to neurons, or rather the formation of contacts between the necessary neurons, that the memorization of an object or event takes place, and short-term and long-term memory differ only in the stability of such contacts.
Scientists even know which signaling molecules-mediators are allocated at each stage of memory work, but no one has been able to control them, fortunately for science fiction writers, until now.
Neurophysiologists from the University of Georgia and their Chinese colleagues decided to fix this flaw. To do this, they focused their attention on an enzyme called alpha-calmodulin-dependent protein kinase type II (α-CaMKII), the concentration of which varies rapidly and significantly in individual neurons at different stages of learning. First of all, its allocation occurs at the stage of memory reproduction, but its concentration also changes during other memory-related processes. Logically assuming that controlling this process could change the normal course of events, the scientists set to work.
To begin with, they genetically altered a section of mouse DNA in such a way that it became susceptible to a specially created substance NM-PP1 – so that injection or ingestion with water of this "starter drug" instantly affected the synthesis of α-CaMKII. Of course, such a result could be achieved by genetic methods alone without additional drugs, but the proposed combined method allows you to enhance protein synthesis not constantly, but only at the necessary moments, and very quickly and for a short time.
At the second stage of the experiment, the scientists tested the effect of such pharmacological and genetic intervention on the work of memory.
Since it was not possible to interview the subjects, Tsen used classical methods – a test for recognizing new objects and a test for fear. In the first case, mice were placed in an enclosed space for three days, after which an object unfamiliar to rodents was placed there for 15 minutes. Depending on how many minutes out of these 15 the mouse was interested in a new toy, scientists concluded about the degree of familiarity. Naturally, if the object was placed a second time, then this time was significantly reduced.
Genetically modified mice did not differ in behavior from ordinary mice, but as soon as they were given a dose of a starting drug before another meeting with a familiar object, they began to perceive it as an unfamiliar one.
Scientists found the same phenomenon of forgetfulness in the fear test, both an hour and a month after the formation of reflexes. In such experiments, instead of the "dating time", the "fading time" is measured – the period when only the respiratory muscles work, and the rodent turns into a small motionless lump. And there is something: unlike Pavlov, the Price was accompanied by a sound signal not with a bowl of food, but with an electric discharge. Accordingly, if the mice heard this sound of a certain frequency for the second time, then this was followed by fright and the mentioned fading. But, as in the "novelty" test, only until they received the magic trigger drug.
Scientists have separately verified that the gene-pharmacological complex works precisely at the moment of reproduction and is not associated with a temporary blockade of memory in general, but with the erasure of "unpleasant memories".
Moreover, they showed that it is not just about blocking reproduction, but about "erasing" the memory that the mouse was trying to reproduce under the influence of a starting drug.
According to experts, this work will help shed light on the memory device – including human memory in general.
People should not expect something like a "starter drug" in the near future, because in this case they will have to embed a piece of DNA into the genome at the stage of embryonic development. And the resulting organism will be too susceptible: after all, everything that he tries to remember while "under the dose" will immediately be erased, and vital information may also get into this list. The details of the work can be found in the latest issue of the journal Neuron.
Portal "Eternal youth" www.vechnayamolodost.ru23.10.2008