Improve memory retention with just chocolate and a nap!

If you want to memorize information for your exam but you like to sleep, you may have found the best way to help your brain retain information. Continue reading to find out how you can do it.

It is well known that adequate sleep plays an important role when we talk about information retention in memory. Some years ago, it was believed that while we were sleeping, memory only kept information passively. However, recent studies show that brain memory actually stores information actively during sleep, choosing which memories to store and what stimuli to associate them with. This process is called consolidation [1].

 - Brain memory actually stores information
actively during sleep,
choosing which memories to store
and what stimuli to associate them with -

Studies have revealed that during the consolidation of information in animals a re-play of neuronal activity occurs in the brain memory, and simultaneously, brain structures responsible for the reward activate during short wave sleep [2]. It is believed that this means the brain circuits responsible for the reward facilitates cerebral plasticity during deep sleep.

Experiment

A study developed by several universities in Switzerland shows that human memory works in a similar way to that of animals [3]. If so, we could reproduce the same stimuli to help our memory consolidate the information we want to learn.

 
- We could reproduce the same stimuli
to help our memory consolidate the information
we want to learn -

Two groups of people participated in the experiment and the following steps were carried out:

1. PVT 1 - The participants made the first PVT.

2. Encode - Each patient had to memorize 8 sequences of cards with images.

3. Learning - The memorization of the sequences was reinforced by having the participant practice the sequences, and providing feedback after each choice made. Each sequence was associated with a reward; 4 of these sequences were associated with a high reward HR, and the remaining 4 sequences were associated with a low reward HR.

4. Sleep / awake - The first group (sleep group) slept after learning, while the second group (awake group) stayed awake. The nap group slept for 90 minutes, while the awake group was taken to a room where they had to remain silent and awake. During these 90 minutes, brain activity was monitored with an electroencephalography (EEG) V-Amp system from Brain Products (Click here for more information about the V-Amp).

5. APV 2 - The participants made the second PVT.

6. Test 1 - The participants went through the first test, in which they were shown a card. The participants had to choose other cards related to the card shown.

7. APV 3 - After three months, each patient was called for a follow-up. Initially, they made the last PVT.

8. Test 2 - Finally, each participant underwent the test described in step 6 (Test 1) for the second time.

* Note: The psychomotor vigilance task(PVT) ensures that all participants are within a range of surveillance values.

When analyzing the results of the tests and the EEG signals taken with the V-Amp (Click here for more information about the V-Amp), interesting results were found.

Short-term memory results

At the beginning of the learning process (Step 3), the participants obtained better results by memorizing the sequences with high reward (HR). But at the end of the learning process, there was no significant difference between the results obtained with the high reward (HR) sequences and the low reward (LR) sequences.

- The group that took the nap obtained
better results than
the group that remained awake! -

After the participants took a nap or stayed awake they executed the first test. In other words, the short-term memory test (Test 1). In general, the group that took the nap obtained better results than the group that remained awake! Within the naptime group, participants performed better by remembering high reward (HR) sequences relative to low reward (LR) sequences.

The EEG showed a correlation between slow spindle sleep activity during sleep (brain activity characterized for being present during light sleep transitions), and better results in test 1 [4].

Long-term retention results

This is where I found some unexpected results; Although as expected, in the group of the nap, better performance was obtained with the high reward (HR) sequences, in the awake group (group that did not take a nap) the participants performed equally when remembering the high reward sequences (HR) and low reward (Click here for more information about the V-Amp)). So, sleeping really makes a difference!

Conclusion

You can definitely facilitate information consolidation by taking a nap after a reward while studying for your exam. But do not let yourself get carried away, because a longer nap showed NO improvement in the performance of memory retention. So indulge yourself with your favorite dessert, take a short nap, and consolidate your memories!

References

[1] Rasch, B., & Born, J. (2013). About sleep's role in memory. Physiological reviews, 93(2), 681-766. doi: 10.1152/physrev.00032.2012
[2] Lansink CS, Goltstein PM, Lankelma JV, Mcnaughton BL, Pennartz CMA. (2009). Hippocampus leads ventral
striatum in replay of place-reward information. PLoS Biology 7:e1000173 doi: 10.1371/journal.pbio.1000173.
s008.
[3] Kinga I., Giulia G, Virginie S. & Sophie S. (2015). A nap to recap or how reward regulates hippocampal-prefrontal memory networks during daytime sleep in humans.
[4] Tuck April 12, 2017. Sleep Spindles. https://www.tuck.com/sleep-spindles/