Claude Monet Argenteuil

Claude Monet ArgenteuilGustav Klimt Danae (detail)Salvador Dali Les Elephants
They started by looking at short-term memories. When caged mice are given a small electric shock, they normally freeze in fear when returned to the cage. However, then injecting them with a drug to inhibit a day after the shock, methyl groups were being removed from a gene called calcineurin and added to another gene. Because the exact pattern of methylation eventually stabilised and then stayed constant for seven days, when the experiment ended, the researchers say the methyl changes may be anchoring the memory of the shock into long-term memory, not just contrmethylation seemed to erase any memory of the shock. The researchers also showed that in untreated mice, gene methylation changed rapidly in the hippocampus region of the brain for an hour following the shock. But a day later, it had returned to normal, suggesting that methylation was involved in creating short-term memories in the hippocampus (Neuron, DOI: 10.1016/j.neuron.2007.02.022).To see whether methylation plays a part in the formation of long-term memories, Miller and Sweatt repeated the experiment, this time looking at the uppermost layers of the brain, called the cortex.They found that olling a process involved in memory formation.