For the first ever time, scientists at the Scripps Research have discovered a physiological mechanism in the brain through which a memory is formed and then subsequently forgotten.
Scientists conducted the study on fruit flies. They conditioned the flies to associate a particular odor with an electric shock. Once they’ve been trained, scientists observe that they subsequently avoid that odor, which confirms that the memory has been made.
They then monitored the activity of neurons in the brain while conditioning procedure. Doing this, they were able to get an inside look at the physiological underpinnings of memory arrangement.
First author Jacob Berry, Ph.D., a postdoctoral associate in the Department of Neuroscience on Scripps Research’s Florida campus said, “We believe this system is set up to remove memories that are unimportant and not necessarily supposed to last a long time. I find it elegant that all of this is done with the same neuron. Our paper highlights exactly how this is achieved.”
For the study, scientists used imaging techniques to look at the process in more detail. They discovered that when a behavioral memory is degraded, the cellular changes made during the learning process are reversed by the same dopamine neuron that helped form the changes in the first place.
Scientists found that when dopamine 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 on Scripps Research’s Florida campus said, “Whenever you learn something new, you’re simultaneously forming a new memory while potentially interfering with or erasing old ones. It’s a very important balancing act that prevents you from becoming overloaded.”
First author Ron Davis, Ph.D. said, “For decades now, neuroscientists studying learning and memory have focused on how the brain acquires information and how that information is made to be stable memory, a process called memory consolidation. Only recently have neuroscientists grasped the importance of active forgetting and begun to unravel the processes that cause the brain to forget.”
Berry said, “This learning-and-forgetting process helps to explain retroactive interference, a common observation in psychology. Retroactive interference describes the situation when more recent information gets in the way of trying to recall older information—for example, calling your former boss by your current boss’s name.”
According to scientists, the findings will apply to higher organisms, including humans. The study does not only provides new insights into the brain mechanisms for active forgetting but offers a wonderful example of how much we learn about brain function from laboratory animals like the fruit fly, Drosophila.
The study was published in Cell Reports.