Summary: According to research, positive emotions, especially in the non-REM stage, improve visual memories while sleeping. They found that thoughts that are related to satisfying experiences last longer than those that are negative. By activating a tri-regional loop with the motor and sensory neocortex, the brain assists in strengthening these thoughts.
Mental recordings established that this loop reactivates when not in REM sleep, strengthening visual memories. Memory engagement was impacted by blocking brain signals during non-REM sleep, whereas blocking them during REM sleep had no result. These results offer novel treatments for conditions like addiction and Anxiety by focusing on non-REM rest processes.
Important Information:
- Non-REM Memory Reinforcement: Physically linked visual reminiscences are strengthened during non-REM rest, no REM sleep.
- Amygdala’s Role: The brain, motor cortex, and visual cortex function together to combine mental memories.
- Prospective Treatments: Modulating brain activity during non-REM rest could help treat dependancy and PTSD-related flashbacks.
Origin: RIKEN
Researchers at the RIKEN Center for Brain Science ( CBS ) have discovered how sleep-related perceptual memories, such as joy and happiness, are strengthened.
The review, published in the medical journal , Neuron, may help scientists understand the neural basis for overcoming problems like substance or physical addiction.
Why do mental activities, whether positive or negative, create solid, long-lasting recollections of external data such as music, image smells and textures received at the events?
We know that sleep is essential for memory combination, the process that turns fresh activities into thoughts, but do not know how it plays its role in memory improvement.
Although research has demonstrated that psychological events may be handled differently depending on the level of slumber, it’s still unclear whether REM sleep, or non-REM sleep, is more crucial for solidifying them.
This problem was the subject of the brand-new research from RIKEN CBS, led by Masanori Murayama.
To examine how the brain functions separately while undergoing rest when emotions are present, the researchers first created mouse equivalents of natural and emotional events.
Men mice were only permitted to observe a soft feel as a learning experience on day 1 of the experiment, and both grooved and soft textures as their testing period the following day.
Because mice have an innate desire for novel environments, they preferred to explore the grooved texture, but not the smooth texture when their memory of the smooth texture lasted until day 2.
However, when the smooth texture was paired with a positive emotional experience—interaction with a female mouse—the memory of the texture lasted much longer. The mice still preferred the smooth texture even after a four-day break, which suggests that this experimental setup might lead to mice with emotionally enhanced texture memory.
This is the first study to demonstrate perceptual memory enhancement through emotion in experimental animals, according to Murayama. We were able to do so, and as a consequence, identified critical neural circuitry involved in perceptual memory enhancement”.
The researchers identified the amygdala, the brain’s emotional center, as key to this process.
As previously discovered by Murayama’s group, the amygdala communicates with a cortical top-down circuit from the motor to the sensory cortices, which ensure accurate perception and memory of texture information. This tri-regional circuit strengthens perceptual memories that are emotionally linked.
These three brain regions were cooperatively activated during the learning periods and reactivated during early non-REM sleep, but not during REM sleep, to reinforce the memory, according to brain recordings.
The researchers temporarily prevented amygdala inputs to the motor cortex, which sends top-down inputs to the sensory area, to test the significance of the non-REM reactivation.
Despite the emotional impact, mice were unable to retain the texture memory until day 5 when they did this while they were not sleeping. Contrary to this, blocking REM sleep’s signals did not work, demonstrating that non-REM sleep is essential for developing perceptual memories.
” Traditionally, REM sleep has been thought to be the primary stage for emotional memory processing”, says Murayama.
Our findings challenge this notion and instead support non-REM sleep as the crucial stage.
This study provides an explanation of how emotion enhances other types of memories, such as perception, and provides information on potential treatments for addiction, where symptoms are occasionally triggered by perceptual information in a phenomenon known as flashback. In connection with emotional events that occurred even long before the episodes, it is believed that this information is firmly memorized.
Doctors could potentially prevent or treat addiction by modulating brain activity in the amygdala and related regions during non-REM sleep by reducing perceptual memories that trigger flashbacks.
Future research will examine how these findings apply to disease models like those involving aging-related memory loss or addiction.
” For instance, it will be important to examine whether we can recover or even strengthen memories in aged-mice”, says Murayama.
” We want to use this knowledge to create treatments that enhance memory and mental health,” the company said.
About this information on sleep and memory research
Author: Masataka Sasabe
Source: RIKEN
Contact: Masataka Sasabe – RIKEN
Image: The image is credited to Neuroscience News
Original Research: Open access.
” Amygdalo-cortical dialogue underlies memory enhancement by emotional association” by Masanori Murayama et al. Neuron
Abstract
Amygdalo-cortical dialogue underlies memory enhancement by emotional association
What is remembered from experiences in the most important way depends on emotional arousal. It is alleged that emotional stimulus-related amygdala activation promotes memory consolidation in the brain’s downstream regions.
However, the physiological basis of the inter-regional interaction and its functions remain unclear.
We demonstrated that the amygdala enhances perceptual memory retention by adding emotional information to a perceptual recognition task that relied on a frontal-sensory cortical circuit in mice. Amygdala not only associates emotional information with perceptual information, but also promotes amygdalo-frontal cortical projections.
Furthermore, emotional association increased reactivation of coordinated activity across the amygdalo-cortical circuit during non-rapid eye movement ( NREM) sleep but not during rapid eye movement ( REM) sleep.
Notably, this increased reactivation was associated with amygdala high-frequency oscillations. During NREM sleep, the syncing of amygdalo-cortical inputs selectively impacted perceptual memory development.
Our findings support the hypothesis that emotion-induced perceptual memory enhancement is caused by inter-regional reactivation triggered by the amygdala during NREM sleep.
