Enhancing Memory Consolidation

Dr. Ken Paller recently did a talk in regards to targeted memory reactivation (TMR) and sleep. Each of us spend about a third of our lives asleep. In the time we are awake, we are constantly learning new things and consolidating that information. In his study, Dr. Paller set out to see if TMR could actually improve learning by selectively encouraging memory reactivation during sleep. Sleeping naturally aids learning and every day we learn things that are important, and others that are not. What makes learning effective is repetition which we can do while awake, but it also occurs while we are sleeping. Dr. Paller discovered that subtle sounds played while sleeping can strengthen memories. Study subjects would learn a memory task that included an auditory component and would then sleep with electroencephalographic monitoring. The sounds were presented during sleep and when the subjects woke up, their memory was tested. General memory consolidation is a normal part of sleeping. However, with TMR, the consolidation mechanisms can be improved and specific memories can be reactivated during sleep to strengthen them. Paller also found TMR to provide an advantage for learning a specific skill, enhancing good habits, and improvement in a therapeutic setting.

The article “How the brain consolidates memory during deep sleep” by Iqbal Pittalwala of Science Daily also talks about the consolidation of memory during sleep. It opens up by stating that even though our bodies are not very active during sleep, our brain is. There are high frequency brain waves from the hippocampus and large amplitude, slower waves in the cortex. The memories we make throughout are day are initially stored in the hippocampus, and some are then progressively transferred to the cortex as long-term memory during sleep. Researchers from UC Riverside developed a computational model which demonstrated that synaptic changes affect the patterns of slow oscillations. This promotes a kind of reinforcement of specific firing sequences of the cortical neurons which represents a replay of specific memory. This can lead to increased learning and consolidation of memories in the brain. Their research found a mechanistic explanation for how memories are formed in the cortex and become independent of the hippocampus. By influencing these oscillations, the hippocampal input activates selective memories during sleep and causes a repetition or rehearsal of these memories. This relates back to Dr. Paller’s research since he used TMR to actually strengthen this effect and to target specific memories. The article states that when memories are rehearsed in the brain, the corresponding synapses are strengthened. Dr. Paller discussed the plasticity of the brain. The more you use a part of your brain, the stronger the synaptic network will become.

The research study along with this article demonstrate just how important sleep is for learning. There is an average of 4-5 alternating cycles of NREM and REM in an eight-hour sleep period. Therefore, it is important to get enough sleep so that we can effectively learn and form new memories. We now know it is even possible to improve recollection through the methods used by Dr. Paller involving TMR.

References:

https://www.sciencedaily.com/releases/2016/04/160414214830.htm