Animal study highlights importance of brain activity during sleep for memory accuracy, strength
New research appearing in the April 9 issue of the Journal of Neuroscience highlights the important role sleep plays in strengthening and maintaining the accuracy of a memory and hints at why the brain shuts out sensory information during periods of deep sleep. The study found that introducing new odor information to an animal while it sleeps compromises its ability to remember the difference between new and previously encountered smells while awake.
During sleep, the brain performs a number of important repair and maintenance duties that are necessary for normal functioning, including moving information from short-term to long-term memory. Previous studies show that the “replay” of recently learned information during sleep plays an important role in memory storage. However, it was unknown whether introducing new information during slow-wave sleep (SWS) — a phase of deep sleep during which the brain’s sensory systems are far less responsive to external stimuli — affects memory.
In the current study, Dylan Barnes and Donald Wilson, PhD, of the City University of New York, the Nathan Kline Institute for Psychiatric Research, and New York University Langone Medical School exposed rats to new and previously encountered odor information while the animals slept. To precisely control the animals’ odor experience during periods of wakefulness and sleep, the researchers delivered electrical stimulation to brain circuits involved in odor processing rather than relying on the delivery of real odors to the animals.
Exposure to new odor information during sleep made it more difficult for the animals to distinguish the learned odor from the other odors. “While previous work has demonstrated the role of sleep replay on memory strength, these are the first data to show that memory accuracy can also independently be influenced during sleep,” Wilson said.
Before introducing odor information to the animals as they slept, Barnes and Wilson taught the animals to associate specific odor information with a mild foot shock while they were awake. After the animals learned to make the association between the odor experience and shock (demonstrated by enhanced fearful behavior), Barnes and Wilson recreated the odor experience when the animals were in SWS.
Animals that received a replay of the learned odor experience during SWS demonstrated increased memory for the odor compared with animals that received a similar replay of the odor while awake. In contrast, the animals that received a replay of new odor information as they slept demonstrated greater difficulty distinguishing the learned odor they were previously exposed to from others.
“We know that during slow-wave sleep, the brain’s sensory systems are far less responsive to normal inputs,” Wilson said. “Our data suggest this sensory isolation may help allow replay of learned information in the absence of external interference, providing strong, precise memory of important information.”
Jan Born, PhD, a neuroscientist who studies sleep at the University of Tübingen and was not involved in this research, noted such information may one day prove important for efforts to reduce traumatic memories. “The question of whether cueing memories during sleep, and specifically during slow-wave sleep, can be used to modify specific memories is currently a hot topic due to the potential for such information to lead us to new ways to weaken the unwanted memories commonly found in psychiatric conditions such as post-traumatic stress and anxiety disorders,” he explained.
4 thoughts on “Processing new information during sleep compromises memory”
This is a very enlightening topic. It makes the relationship between sleep,learning and memory very clear. It clearly indicates the importance of sleep in having a fully functional brain activity.
This specific topic of research is very interesting and may help support earlier clams of the importance of sleep. This research can also be linked to the fact that sleep plays a crucial role in learning from early in development. Research has been done in the past by Rebecca Gómez of the University of Arizona which looks specifically at how sleep enables babies and young children to learn language over time and this study only supports these claims further.
This new research development may be able to provide critical information that is able to support and back up pervious clams.
I can confirm this very directly. I suffered an brain injury 28 years ago. A year after that my brain developed epilepsy. It did nothing but get worse for another 20 years, as my cognitive abilities (memory, reasoning) declined at more or less the same rate as the epilepsy. Doctors though that the epilepsy could be removed or improved with brain surgery if they could identify any particular area of my brain that was inciting the seizures.I was strapped to a detail EEG device for 2 days and they determined that there was a local area of my brain that seemed to be stimulating the seizures. A year later they performed surgery to remove the epilepsy “inciter”. In the entire time before that surgery I had not had a single dream. A matter of days after the surgery I began having REM sleep again – dreaming. Since that time both my memory and epilepsy events have improved gigantically.
Thanks for this enlightening piece. I think sleep in our modern day society is underestimated. We’ve seen lots of patients come to our clinic (http://advmedny.com/) with memory problems. This piece of research seems to confirm our suspicion.
Advanced Medical Care
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