Huberman #72 - Understand & Improve Memory Using Science-Based Tools

Things done to memorize:

• Repetition. Coavtivation of neurons will strengthen their connections (Hebbs postulate). Most of the time when we learn something, existing neurons strengthen their connection through repeated coactviation, or, through a very strong coactivation once and only once.

So how do we get strong activations between neural circuits to learn things with fewer repetitions than otherwise?

Some types of memory : Short term (working memory, small things one is not expected to remember the next day), Medium term and Long term (ability to commit certain patterns of cognitive, motor etc. information over long periods of time, up to years). Some other categories: Explicit declarative memory (fact that you can declare you know something, like your name - you know something and you know you know it), Explicit procedural memories (involve action-sequences, like walking, which involves describing walking for example), Implicit memory (your nervous system knows how to walk without you actually thinking about what you know regarding walking).

Explicit declarative memories are formed in the hippocampus. Implicit memories are formed and stored elsewhere, like in the cerebellum and neocortex.

Patient HM : Had intractable epilepsy. The frequency and intensity was so robust, the neurologists decided to find and remove the related brain tissue - which happened to be the hippocampus. Then, he lost all explicit memory. He did have some memory of previous events, as they are not stored in the hippocampus itself. He still had implicit knowledge, like how to make a coffee, names of people he met way before etc. Telling him a joke the first time he would laugh a lot, then he would forget it, but if the joke is told the next time he would laugh less. This suggests than humour is more related to procedures like walking etc. rather than the exact content.

The story about HM and how he perceives jokes is relevant, since emotion itself turns out to be the way to enhance memory, even if those are memories for things that are not funny/sad/happy etc.

There are particular neurochemicals that you can leverage to learn specific information faster and remember it longer or even forever.

One tool that will always work : repetition.

Having an emotionally intense (positive/negative) sentence or two when reading a paragraph leads to better recall and accuracy in what was remembered. A heightened adrenaline response (e.g. putting arm in ice cold water) after reading something, leads to remembering things that are not emotionally intense.

High emotional states help you remember things better, but it is mediated by the presence of adrenaline that allows for this.

The emotional state you are after reading something you want to remember dictates whether or not you will learn it quickly or not. So, we need some tools to increase adrenaline release at will.

It is optimal to do what increases the adrenaline after the bout of learning afterwards. The best time window is immediately after, or around 5 minutes after trying to learn it, whether it be cognitive information or a physical skill.

Brief naps of 20-90 minutes after an attempt to learn can enhance the rate of learning and memory - this can be performed up to some hours after the learning bout.

Ideal protocol - focus on the thing you are trying to learn very intensely, get excellent sleep, nap anything from 10-90 minutes (if it does not interrupt night time sleep) and spiking adrenaline in a safe way immediately after the learning bout.

To spike adrenaline, you don't need any pharmocological substance like caffeine.

It is not the absolute amount of adrenaline that matters, it is the amount of adrenaline released relative to the amount that was in your system prior.

Note that chronic stress and chronic elevation of epinephrine (adrenaline) inhibits learning and memory.

Exercise is also a great tool to enhance learning and memory. Cardiovascular exercise especially important - 180-200 minutes of zone-2 cardio a week is the minimum threshold to enhance longevity effects, and indirectly leads to improvements that help learning and memory.

Up to 2 hours after exercise lead to big increases in adrenaline.

In short, if the exercise is gonna give a big spike of adrenaline (i.e. taking serious effort), you would want to do it after a learning bout. To use exercise to enhance blood flow, to augment the hippocampus etc. then doing 1-3 hours before the attempt to learn is suggested.

Visual function is powerful way to enhance memory - this can be used as a tool: if people are allowed to choose what they take photos of, taking those photos (via camera, or even a mental picture) enhanced their memory of the places, people, objects and their details - keeping or deleting the photoes does not matter. It however degrades ability to remember auditory information at the time.

Another tool is meditation. A 13-minute simple meditation vs. a 13-minute podcast over 8 weeks had a significant effect on improving attention, memory, mood and emotion regulation. One important point in this study is that meditation impaired sleep quality - this was because it was done late in the day (sometime between 8-11pm). Attention abilities improved in daily meditators as well, and this may inhibit ability to sleep. Note that doing 4 weeks instead of 8 weeks, these effects did not show up.