Memory Consolidation: Time Machine of the Brain

How does sleep help us remember things better?
In this video we will explore the wonders of the hippocampus - a brain region involved in memory consolidation and spatial navigation. We will talk about the phenomenon of hippocampal replay and the Sharp Wave Ripples.

My name is Artem, I'm a computational neuroscience student and researcher at Moscow State University.
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Special thanks to Crimson Ghoul for providing English subtitles!

OUTLINE:
00:00 Introduction
01:01 Sponsor message
02:23 Cortex and Hippocampus
04:52 Sharp Wave Ripple
06:45 Fast-reverse memory replay
08:55 Fast-forward replay
10:03 Conclusion and Outlook

REFERENCES:
1.Ólafsdóttir, H. F., Bush, D. & Barry, C. The Role of Hippocampal Replay in Memory and Planning. Current Biology 28, R37–R50 (2018).
2.Hannah R. Joo & Loren M. Frank. The hippocampal sharp wave-ripple in memory retrieval for immediate use and consolidation. Nature Reviews Neuroscience (2018) doi:10.1038/s41583-018-0077-1.
3.Buzsáki, G. The brain from inside out. (Oxford University Press, 2019).
4.Roux, L., Hu, B., Eichler, R., Stark, E. & Buzsáki, G. Sharp wave ripples during learning stabilize the hippocampal spatial map. Nat Neurosci 20, 845–853 (2017).
5.Girardeau, G., Benchenane, K., Wiener, S. I., Buzsáki, G. & Zugaro, M. B. Selective suppression of hippocampal ripples impairs spatial memory. Nat Neurosci 12, 1222–1223 (2009).
6.Feld, G. B. & Born, J. Sculpting memory during sleep: concurrent consolidation and forgetting. Current Opinion in Neurobiology 44, 20–27 (2017).
7.Ambrose, R. E., Pfeiffer, B. E. & Foster, D. J. Reverse Replay of Hippocampal Place Cells Is Uniquely Modulated by Changing Reward. Neuron 91, 1124–1136 (2016).
8.Marcelo G. Mattar & Nathaniel D. Daw. Prioritized memory access explains planning and hippocampal replay. Nature Neuroscience (2018) doi:10.1038/s41593-018-0232-z.
9.Jens G. Klinzing, Niels Niethard, & Jan Born. Mechanisms of systems memory consolidation during sleep. Nature Neuroscience (2019) doi:10.1038/s41593-019-0467-3.
11.Wenbo Tang, Justin D. Shin, Loren M. Frank, & Shantanu P. Jadhav. Hippocampal-Prefrontal Reactivation during Learning Is Stronger in Awake Compared with Sleep States. The Journal of Neuroscience (2017) doi:10.1523/jneurosci.2291-17.2017.
12.Buzsáki, G. Hippocampal sharp wave‐ripple: A cognitive biomarker for episodic memory and planning. Hippocampus 25, 1073–1188 (2015).
13.Diba, K. & Buzsáki, G. Forward and reverse hippocampal place-cell sequences during ripples. Nat Neurosci 10, 1241–1242 (2007).
14.Shin, J. D., Tang, W. & Jadhav, S. P. Dynamics of Awake Hippocampal-Prefrontal Replay for Spatial Learning and Memory-Guided Decision Making. Neuron 104, 1110-1125.e7 (2019).
15.Mehta, M. R. Cortico-hippocampal interaction during up-down states and memory consolidation. Nat Neurosci 10, 13–15 (2007).
16.Aussel, A., Buhry, L., Tyvaert, L. & Ranta, R. A detailed anatomical and mathematical model of the hippocampal formation for the generation of sharp-wave ripples and theta-nested gamma oscillations. J Comput Neurosci 45, 207–221 (2018).

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This video was sponsored by Brilliant

[simoneparvizi]

Keep it going man. The quality is insane, you deserve more! Cheers from Italy

[tomsnow]

In fact theres evidence proving we actively and passively forget alot of information throughout the day, and this information dump of actively and passively forgetting things we deem unimportant, is precisely what allows us to learn. The balance between active forgetting during the day and memory consolidation during the night is what makes the brain so effective.

[arfyness]

wow you're incredibly good at explaining such complex things
i've not understood these concepts until now

[LucGendrot]

Fast-reverse memory replay reminds me of how eligibility traces and TD(lambda) in reinforcement learning work, by updating the Q value of each past visited state after receiving a reward in the "current" state, and how the reward filters back essentially in reverse order of visitation.

Obviously it's not at all the same, but it's cool how even though TD(lambda) wasn't created with this biological process in mind, it still forms a loose analogue to how the "real thing" works.

[rodrigocalixto]

Hey Artem, I just wanted to say that I absolutely love the content you make, specially the videos about specific neuroscience topics. Please never stop!! :)

[victoriaporozova]

I like how Artem had 9k while asking us to follow and now he has gotten ~x10 times more. He will grow to the million. This channel and the content is brilliant. Doing Quantum AI + theoretical physics related research right now. It is funny how biology inspires new models in AI a lot. Keep it up! Greetings by a Saint Petersburg’s 🇷🇺physicist from Brazil 🇧🇷🙌🏼

[MrMikkyn]

I had no idea the hippocampus was doing that while we were sleeping. I knew we had memory consolidation during REM, but not this hippocampal cell spiking. This is so fascinating wow. My god 😮

[filippq]

Ну наконец новый видос! Ты уже так вырос… Настоящий медиагигант!
Когда 100к подписоты отмечать позовёшь?
Роста тебе в этом ремесле!

[reillytilbury]

Your videos are so well made and informative. As someone who has recently entered neuroscience, you're a fantastic and enthusiastic teacher!

[qwertywifi]

Man this channel is insane. Can't believe I'm watching this for free

[recca]

I spend 7/10 in sleep, no memory to consolidate

[jamesjenkins]

Woah. This is awesome content. IDK how I found you, but please keep making this!

[mukuls]

Your video content is amazing. Also you edit video like a professional. Smooth and subtle sounds with near perfect animation

[DistractANoodle]

Incredible work. My future self and I thank you for enriching our brains :)
Now to refine the notes I've taken!

[Fractalma_]

You are the best divulgator, Artem. Greetings from a cognitive neuroscientist from the Canary Islands, Spain

[stuartferguson]

Reinforcement learning ends up recording events and processing them backwards because it's easier to compute the Bellman equation that way. Now I learn the brain already does that. Amazing!

[JahHoor]

Lemme take a nap to remember what this video was about thx

[senseofmindshow]

This is such a fascinating topic, and I had never heard of the reverse order replay that you explained. Just an excellent video and explanation! Your animations are beautiful.

By the way, I also make neuroscience videos so if you would ever be interested in collaborating, let me know!

[os]

Excellent job! As a neuroscientist myself I can say great work!

[JJEvita]

"Trajectories the mouse was taking during the day at night recapitulate during the shark wave ripple. And that means that the same place cells were activated one atfer another as if representing the same trajectory only their order was reversed and the time scale of the entire thing was much smaller."