Forgetting With Cockroaches

Madeira Cockroach

Studies of memory in mammals have identified some of the biochemical pathways involved in sustaining memories. Zeta inhibitory peptide (ZIP), an inhibitor of a neural system enzyme, Protein Kinase C (PKC) was demonstrated to erase long term memories in mammals. Experiments were extended to the sea snail, (Aplysia) an important model animal for studies of the nervous system. ZIP also causes memory loss in Aplysia. A group of scientists* asked, “Does ZIP induce memory loss in insects?”

The answer is yes. The answer to their question required an insect that can remember. The Madeira Cockroach can be trained to odor by offering food reward. The cockroaches can be given an odor such as vanilla or peppermint along with a slice of apple. After repeated rewards, the cockroaches associate the odor with the apple and will seek the odor source when hungry. Madeira Roaches were trained to the odor, then injected ZIP. Cockroaches injected with ZIP no longer responded to the odors. The cockroaches had forgotten that the odor was associated with food.

The memory process appears to be evolutionarily conserved throughout the animal kingdom. Demonstrating that the process is similar in insects and mammals opens the potential to use insect models, such as cockroaches and Drosophila long term memory studies. Many types of experiments can be done easily in insects that are difficult or not possible in mammals. Insect studies will continue to contribute to advances in science and medicine that improve the human condition.

*Zhouheng Deng, Alexander J. Lubinski, Terry L. Page. 2015. Zeta inhibitory peptide (ZIP) erases long-term memories in a cockroach. Neurobiology of Learning and Memory. 118: 89-95.
http://www.sciencedirect.com/science/article/pii/S1074742714002081