Neocortical olfactory memory erasure
Rapid Erasure of Long-Term Memory Associations in the Cortex by an Inhibitor of PKM{zeta}
Reut Shema, Todd Charlton Sacktor, Yadin DudaiLittle is known about the neuronal mechanisms that subserve long-term memory persistence in the brain. The components of the remodeled synaptic machinery, and how they sustain the new synaptic or cellwide configuration over time, are yet to be elucidated. In the rat cortex, long-term associative memories vanished rapidly after local application of an inhibitor of the protein kinase C isoform, protein kinase M zeta (PKM{zeta}). The effect was observed for at least several weeks after encoding and may be irreversible. In the neocortex, which is assumed to be the repository of multiple types of long-term memory, persistence of memory is thus dependent on ongoing activity of a protein kinase long after that memory is considered to have consolidated into a long-term stable form.
The authors used conditioned taste aversion (you may be familiar with this learning paradigm if you’ve ever made yourself sick off tequila). Injection of a peptide inhibitor of this enzyme (PKM zeta) completely removed the aversive association. This isn’t a paper about how to erase memories for any clinical application because, for instance, injecting the drug erases multiple olfactory associations (i.e. we don’t have a clue how to achieve specificity). It is a paper about how memory works, and it is pretty remarkable that a simple mechanism like persistent kinase activation may be central to this neural function.
The lack of specificity makes this development more alarming, not less. Hopefully any equivalent in humans will only affect relatively recent memories.
The lack of specificity makes this development more alarming, not less.
I don’t think amnestic was making any comment about how alarming or not this development is. He was only saying that these findings do not directly lead to any practical way to intentionally erase the memory of, let’s say, a particularly gruesome battle fought in the army that causes someone to suffer PTSD, without tampering with everything else.
But I’m more concerned about the people who would want to tamper with everything else.