Research Press Release | November 24, 2015
|Overview||With regard to learning in mammals and insects, it is thought that monoaminergic neurons convey reward and punishment information. However, questions remain concerning which types of neurotransmitters and transmitter receptors are involved in this activity. The group of Professor Makoto Mizunami of Hokkaido University, in joint research with the group of Assistant Professor Taro Mito of Tokushima University, used genome editing technology known as CRISPR/Cas9, to successfully create knockout crickets for which the dopamine receptor Dop1 does not function normally. In these crickets, associative learning involving odor and rewards is normal, but associative learning involving odor and punishment is not possible. We learned that Dop1 conveys punishment information but does not convey reward information. This research makes a great contribution to the elucidation of learning mechanisms in animals.|
In associative learning in animals, mechanisms for conveying punishment and reward information have long been a topic of research. In mammals, including humans, dopamine neurons convey reward and punishment information; however, in invertebrates, our pharmacological research using two-spotted crickets suggests that octopamine neurons convey reward information and dopamine neurons convey punishment information. Recently, however, based on research using transgenic fruit flies, it has been reported that dopamine neurons convey both reward information and punishment information via the dopamine receptor Dop1. The purpose of our research is to clarify whether this discrepancy is due to a difference in research methods or to a difference in learning mechanisms between insect species.
Crickets have a high learning ability, and they have points in common with mammals in regard to their learning mechanisms. For example, we previously reported that learning occurs through surprise when an unpredicted event occurs. This prediction error theory for mammals also applies to crickets. In the future, by continuing our research using genetically modified crickets, we expect to be able to accelerate the elucidation of the basic mechanisms of learning and memory in animals.
Makoto MIZUNAMI, Professor, Graduate School of Life Science, Hokkaido University
TEL & FAX: +81-11-706-3446
|Publications||Knockout crickets for the study of learning and memory: Dopamine receptor Dop1 mediates aversive but not appetitive reinforcement in crickets, Scientific Reports (11.2.2015)|