Dr. Andrew Huberman, Ph.D. is a Professor of Neurobiology and Ophthalmology at Stanford University School of Medicine. His lab focuses on neural regeneration, neuroplasticity, and brain states such as stress, focus, fear, and optimal performance.
In this episode, Andrew Huberman breaks down the mechanisms behind how memories are established in our brains, how to leverage hormones to improve learning and memory, and actionable protocols to enhance learning and memory.   
Host: Andrew Huberman (@hubermanlab)
The nervous system converts physical events in the environment into electrical and chemical systems your body understands
We only perceive and process a small subset of events around us otherwise we’d be inundated with stimuli
Our nervous system is a filter that processes certain events for understanding and then further filtering those events which will be stored as memories
Memory is a bias in which perceptions will be played again in the future, following neural circuit activation
Most of what we remember takes place in the context of something else and is linked by either close, medium, or distant association
Repetition: repeated activation of sequences of neurons which lays the framework for a memory
Sheer repetition is sufficient for learning
“Neurons themselves are not smart – they do not have knowledge. Every memory is the consequence of the repeated activation of a particular set of neurons.” – Dr. Andrew Huberman
Memories are due to a strengthening of existing neurons (not new neurons forming connections) through repetition
One-trial learning: very strong act activation of neurons one time that lasts forever (usually associated with intensely negative or positive events) – such as animal studies in which the animal receives a shock and learns immediately
One-trial learning takes place for positive and negative events
Short-term (working) memory: ability to keep something in mind for a short period for recall within minutes
Long-term memory: the ability to remember a day, week, month, or years later
Categories of memory: (1) explicit declarative memory – you know you know something (e.g., your name); (2) explicit procedural memory – action sequences you remember (e.g., you know the mechanics of walking)
Both declarative and procedural explicit memories can be moved from explicit to implicit (automatically know how to do something)
Explicit memories are stored in the hippocampus (but formed elsewhere)
Implicit memories are formed and stored in the cerebellum and neocortex
People with injuries to the hippocampus will lose explicit memories
“What we know and what we are able to do is the consequence of things we are aware of and learnings that are passed off into subconscious knowledge.” – Dr. Andrew Huberman
Repetition: the firing of a particular sequence of neurons repeatedly will strengthen nerve connections
Emotions can be leveraged to enhance memory
We tend to remember emotionally more accurately and more readily 
Condition, place, preference: we tend to want to go back to the space (whether physical or emotional) where things worked out best – for example, this is why we sit in the same seat in class
Evoking the release of adrenaline improves memory  
Adrenaline does not cross the blood-brain barrier; cortisol can cross the blood-brain barrier
High emotional states help you learn but the presence of high adrenaline, epinephrine, norepinephrine, and cortisol allows memory to form
Caffeine can enhance memory by blocking adenosine (responsible for sleepiness and fatigue), increasing alertness, and increasing dopamine
Consume caffeine immediately after or 5-15 minutes after repetition for optimal memory enhancement and neurochemical release
Alpha-GPC: drugs that increase cholinergic or acetylcholine transmission will increase focus or cognition
Naps and non-sleep deep rest (NSDR): naps of 28-90 minutes after an attempt to learn can enhance memory and learning
Naps and NSDR can take place hours later – not as particular as the timing of caffeine
Cold baths (or sticking your arm in ice water or something comparable) can stimulate adrenaline release – the water should be cold enough that you want to get out
Anything that quickens breathing and makes eyes wide is stimulating adrenaline which is what we’re looking for immediately after learning bout
The more epinephrine released, the more learning & memory takes place
Fun fact: during medieval times, adults would throw children into cold water after they wanted them to learn something because they found it enhanced learning  
Start with behavioral tools – there are great consequences of using pharmaceuticals if they are not prescribed and medically necessary
Don’t abuse the adrenaline system and expect the same results! It’s the amount of adrenaline released relative to the amount of adrenaline that was previously in a system that matters
The amygdala is the center of the brain for threat detection and detection of events linked to emotional states (both positive and negative)
Neurons in the amygdala strengthen connections in the brain easily because it has vast connections
Both negative and positive emotional states are the ways in which memories are laid down
Big picture: the amygdala and neurochemicals are neutrally taking in information – the memories we attach cause us to remember things fearfully or happily and generalize (e.g., if something bad happens in a crowd, we may want to avoid all crowds)
Learning and memory usually involve the strengthening of neural circuits, not an increase in the number of neurons in the brain – with the exception of exercise
Cardiovascular exercise can increase the proliferation of new neurons in a certain structure of the brain which is important for new memories
Cardio dose: 180-200 minutes of zone 2 exercise per week will enhance longevity and stimulate neurogenesis
Bones make chemicals that travel in the bloodstream and have endocrine (from bone to other regions) effects
Load bearing exercises can induce the release of osteocalcin (endocrine hormone) which sends signals to the brain that you are moving, blood is flowing, and the body needs more stimulation
Timing of intense exercise: exercise that will induce a spike of adrenaline and require effort should be completed after learning bout
Timing of cardio: if using exercise to enhance blood flow and osteocalcin release (e.g., zone 2), exercise within 1-3 hours preceding the attempt to learn
Photographic memory: ability to look at a page of text and commit to memory with little effort
People with true photographic memory often have a hard time learning through hearing and physical skills
Super recognizer: people with an extremely accurate ability to recognize faces and match faces to aperson in other settings/footage
Some people are face blind and can’t recognize faces even if they know the person
If people are forced to take photos of a scene or object, their ability to remember it is reduced – memories are better if you are choosing what to photograph  
Taking photographs inhibits auditory recall of events or places
If you want to remember something, take a photo even if you never look at it again
It’s possible that the memory is actually because of the narrowed aperture of the scene
Taking mental snapshots (literally imagining you are taking a photo) enhances visual memory almost as much as taking an actual photo
Meditation can improve attention, memory, mood, and emotion regulation
Study protocol: 13 minutes of meditation per day for 8-weeks (note, there were no significant results after 4-weeks; it appears a longer duration is needed)
Timing of meditation is critical! If meditation is done too late, it can impair sleep because it actually requires a high attentional load – it increases attention back to your body and breath
Meditation puts us into a calm, focused state – but non-sleep deep rest and Yoga Nidra allow us to enter a calm state without high attentional focus
Non-sleep deep rest and Yoga Nidra is a powerful tool to access sleep, calm, and neuroplasticity – similar to hypnosis
The hallmark of Yoga Nidra and non-sleep deep rest is a self-directing state of calm
Zero cost apps for Yoga Nidra: Kamini Desai, Liam Gillen
Paid app for Yoga Nidra: Reverie
Déjà vu: pattern of encoding experiences and events in the hippocampus
Mechanism behind Déjà vu sensation: neurons that were active in one circumstance are becoming active again in the same circumstance
A Novel Demonstration of Enhanced Memory Associated with Emotional Arousal (Consciousness and Cognition)
Mechanisms of memory under stress (Neuron)
Photographic Memory: The Effects of Volitional Photo Taking on Memory for Visual and Auditory Aspects of an Experience (Psychological Science)
Brief, daily meditation enhances attention, memory, mood, and emotional regulation in non-experienced meditators (Behavioral Brain Research)