For the first time, scientists at Scripps Research have discovered a physiological mechanism in the brain through which a memory is formed and then forgotten.
The scientists conducted the study on fruit flies. They conditioned the flies to associate a particular odor with an electric shock. Once they were trained, scientists note that they subsequently avoid this odor, which confirms that memory was made.
They then monitored the activity of neurons in the brain during the conditioning procedure. By doing so, they were able to gain insight into the physiological foundations of the memory arrangement.
First author Jacob Berry, Ph.D., a postdoctoral associate in the Department of Neuroscience at the Scripps Research campus in Florida, said: "We believe this system is poised to remove memories that are not important and do not necessarily last very long time. I think it's smart that all this is done with the same neuron. Our work highlights exactly how this is achieved. "
For the study, the scientists used imaging techniques to examine the process in more detail. They found that when a behavioral memory is degraded, the cellular changes made during the learning process are reversed by the same dopaminergic neuron that helped to form the changes in the first place.
Scientists have discovered that when the dopaminergic neuron is recruited to form a new memory, it also works to degrade older memories.
First author Jacob Berry, Ph.D., a postdoctoral associate in the Department of Neuroscience at the campus of Scripps Research in Florida said, "Whenever you learn something new, you are simultaneously forming a new memory while potentially interfering with or eliminating old ones. It's a very important balancing act that keeps you from getting overwhelmed. "
First author Ron Davis, Ph.D. For decades, neuroscientists who study learning and memory have focused on how the brain acquires information and how this information is made to be stable memory, a process called memory consolidation. Only recently have neuroscientists realized the importance of active forgetfulness and have begun to unravel the processes that make the brain forget. "
Berry said, "This process of learning and forgetting helps explain backward interference, a common observation in psychology. Retroactive interference describes the situation when more recent information hinders the attempt to retrieve old information – for example, call your former boss by the name of your current boss. "
According to the scientists, the findings will be applied to higher organisms, including humans. The study provides not only new insights into the brain's mechanisms for active forgetfulness but provides a wonderful example of how much we have learned about brain functioning from laboratory animals such as the fruit fly Drosophila.
The study was published in the Cell Reports.