Uncoding the 'memory code'
Neurobiologists at UC Irvin are making groundbreaking discoveries regarding memory. By examining how sounds are registered during the process of learning, they have discovered a neural coding mechanism that the brain relies upon to register the intensity of memories based on the importance of the experience.
Neurobiologists have long hypothesized this type of neural coding, but the study presents the first evidence that a "memory code" of any kind may exist. The University of California Irvin scientists think that this code, as well as similar codes that may be discovered, will not only broaden our understanding of normal learning and memory but also may shed light on learning disorders. In future it may be possible to manipulate these codes to control what and how we remember – not only basic sounds, but complicated information and events.
"This memory code may help explain both good and poor memory," said Norman Weinberger, a professor of neurobiology and behavior in UCI’s Center for the Neurobiology of Learning and Memory. "People tend to remember important experiences better than routine ones."
Weinberger and colleagues found that when the brain uses this coding method, storage of information is done in a greater number of brain cells, which should result in a stronger memory. However, the scientists think that if the brain fails to use the code, the resulting memory – even if it is an important one – would be weaker because fewer neurons would be involved.
Weinberger and postdoctoral scientist Richard Rutkowski discovered this coding system through studying how the primary auditory cortex responds to various sounds.
In the study, the scientists trained rats to press a bar to receive water when they heard a certain tone. The tone was varied in its importance to different rats as shown by their different levels of correct performance.
After brain mapping these test rats, the scientists found that the greater the importance of the tone, the greater the area of the auditory cortex that became tuned to it. The results in rats that received the same tones but were trained to a visual stimulus did not differ from those in untrained rats. It showed that the behavioral importance of the tone, not its mere presence, was the critical factor.
Findings from the study appear on the Online Early Edition of the Proceedings of the National Academy of Sciences. The National Institute on Deafness and Other Communication Disorders supported the effort.
About the University of California, Irvine: Celebrating 40 years of innovation, the University of California, Irvine is a top-ranked university dedicated to research, scholarship and community service. Founded in 1965, UCI is among the fastest-growing University of California campuses, with more than 24,000 undergraduate and graduate students and about 1,400 faculty members. The second-largest employer in dynamic Orange County, UCI contributes an annual economic impact of $3 billion. More information on this topic and a number of other exciting research occurring at UC Irvin can be found at the their website.