Troubled by bad memories ? ZIP them !

From the deep labs of neuroscience where rats learn to swim and navigate watermazes comes a new PKZ enzyme called PKMzeta. It has a very impressive role in associative memory and could play a key role in future memory research and pharmacotherapy both by blocking unpleasant memories (fi PTSD) (ZIP: Zeta Inhibitor proteine) as enhancing them (Alzheimer). How long-term memories are stored as physical traces in the brain is a fundamental question in neuroscience. Recently, we discovered the first molecular mechanism of long-term memory storage. We showed that unpleasant memories are stored by the persistent action of an enzyme, a form of protein kinase C, termed PKMζ, because these memories can be rapidly erased by injecting a PKMζ inhibitor into the brain. But are all forms of memory and information in the brain stored by PKMζ? Here, we first confirmed with a second inhibitor of PKMζ that unpleasant long-term memories in the hippocampus, a region of the brain critical for storing spatial information, are rapidly erased. We then examined other memories stored in the hippocampus and the basolateral amygdala, another region critical for emotional memories. We tested memories for specific places, both unpleasant and rewarding, memories for general background information, associations between a sound and a fearful event, like that studied by Pavlov, and memories for performing a specific action. We found that PKMζ stores specific associations, both unpleasant and rewarding, for places, events, and actions, and is thus a general mechanism for memory storage in the brain.