Explain how researchers used the drug ZIP to test its effect on long-term memory. How did they know that food aversion was a longterm memory phenomenon?

The researchers used the drug ZIP to test its effect on long-term memory by injecting it into the brains of rats who had been trained to associate a specific taste with feeling sick. This is a form of classical conditioning, where a subject learns to associate a neutral stimulus (in this case, a taste) with a significant event (feeling sick).

The drug ZIP is known to interfere with the function of a protein called PKMzeta, which is involved in maintaining long-term memories. By injecting ZIP into the rats' brains, the researchers were able to disrupt the function of PKMzeta and thus erase the memory of the taste-sickness association.

The researchers knew that food aversion was a long-term memory phenomenon because the rats continued to avoid the taste even after several days had passed since their last exposure to it. This suggests that the memory of the association was not just a short-term reaction, but had been consolidated into long-term memory.

In addition, the fact that the memory could be erased by disrupting PKMzeta function provides further evidence that it was a long-term memory, as PKMzeta is known to be involved in maintaining long-term memories.