Summary: During sleep, the brain resets memory by silencing specific neurons in the hippocampus, allowing for continuous learning without overloading.
Learning or experiencing new things activates neurons in the hippocampus, a region of the brain vital for memory.
The researchers implanted electrodes in the hippocampi of mice, which allowed them to record neuronal activity during learning and sleep.
Science Abstract A hippocampal circuit mechanism to balance memory reactivation during sleep Memory consolidation involves the synchronous reactivation of hippocampal cells active during recent experience in sleep sharp-wave ripples (SWRs).
CA1 neurons and assemblies that increased their activity during learning were reactivated during SWRs but inhibited during BARRs.
In conclusion, the brain resets memory while you sleep by turning off certain neurons in the hippocampus, which permits ongoing learning without becoming too taxed. A number of hippocampal regions are involved in this process, which is essential for memory consolidation. In particular, CA2 helps reset memory circuits.
This process, according to researchers, may be utilized to improve memory or even remove painful memories. The study sheds light on the necessity of sleep for preserving memory and cognitive function.
Important Information:.
Specific neurons reset during sleep, which aids in memory consolidation.
Neurons involved in reset are largely silenced by the CA2 region of the hippocampus.
One could aim to improve memory or remove painful memories using this mechanism.
The Cornell University is the source.
A recent study from Cornell University reveals that getting enough sleep resets not just energy levels but also memory.
An area of the brain essential for memory, the hippocampal region, is activated when one learns or experiences new things. The brain consolidates memories during sleep by having those neurons repeat the same pattern of activity. The memories are then stored in a large region of the brain known as the cortex.
However, how is it that we do not exhaust our neurons learning new things for the rest of our lives?
According to a recent study published in Science and currently under embargo until 2 p.m. ET on August 15, “A Hippocampal Circuit Mechanism to Balance Memory Reactivation During Sleep,” specific regions of the hippocampus go silent during deep sleep, allowing those neurons to reset.
The paper’s corresponding author, assistant professor of neurobiology and behavior Azahara Oliva, speculated that “this mechanism could allow the brain to reuse the same resources, the same neurons, for new learning the next day.”.
The regions CA1, CA2, and CA3 comprise the hippocampus. Little is known about CA2, which the current study found generates this silencing and resetting of the hippocampus during sleep. CA1 and CA3 are well-studied and involved in encoding memories related to time and space.
In order to record neural activity during learning and sleep, the researchers implanted electrodes in the hippocampi of the mice. This allowed them to see how the neurons in the CA1 and CA3 regions replicate the same neural patterns that evolved during the day during sleep. However, the question that the researchers really wanted to know was how the brain learns new things every day without overtaxing its neurons or running out of them.
“We discovered there are other sleep-related hippocampal states in which everything is quiet,” said Oliva. “Suddenly quiet, the previously very active CA1 and CA3 regions appeared. This state, which is a reset of memory, is produced by the middle region, CA2. “.
The active neurons that are important for functional processes like learning are believed to be cells known as pyramidal neurons. Different subtypes of interneurons, a different type of cell, exist.
The researchers found that these two types of interneurons controlled parallel circuits in the brain, one of which controlled memory and the other of which permitted memory resetting.
By adjusting memory consolidation mechanisms, the researchers think they have the means to improve memory, which they could use when memory function deteriorates, as in Alzheimer’s disease.
Crucially, there is evidence that suggests they should investigate methods of erasing unpleasant or traumatic memories, as this could potentially aid in the treatment of disorders like post-traumatic stress disorder.
The outcome contributes to the understanding of why sleep is necessary for all animals in order to maintain brain function during waking hours and to repair memories. Oliva stated, “We demonstrate that memory is a dynamic process.”.
Funding: This research was made possible by grants from the National Institutes of Health, the Sloan Fellowship, Whitehall Research, Klingenstein-Simons, and New Frontiers.
Regarding this news on sleep, learning, and memory research.
Writer: Bowyer Becka.
The Cornell University is the source.
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Photo credit: Neuroscience News is acknowledged for this image.
Closed access original research.
Azahara Oliva et al. describe “A hippocampal circuit mechanism to balance memory reactivation during sleep.”. science.
Inabst.
memory reactivation during sleep is balanced by a hippocampal circuit mechanism.
Sharp-wave ripples (SWRs), which are hippocampal cells that were active during a recent experience in sleep, are synchronously reactivated during memory consolidation. Unknown is how the counterbalance that maintains network stability amid this spike in firing rates and synchrony after learning occurs.
We identified a network event that occurs during non-rapid eye movement sleep and is caused by an intrahippocampal circuit formed by a subset of CA2 pyramidal cells to cholecystokinin-expressing (CCK+) basket cells. These cells fire a burst of action potentials, known as “BARR.”. While learning-induced activation of CA1 neurons and assemblies was inhibited during BARRs, it was reactivated during SWRs.
Sleep caused the initial rise in reactivation during SWRs to return to baseline.
Silencing CCK+ basket cells during BARRs reversed this trend, leading to better memory consolidation and increased synchrony of CA1 assemblies.
