'Time Cells' Discovered in Human Brains

https://www.npr.org/sections/health-shots/2020/10/29/929133717/why-some-memories-seem-like-movies-time-cells-discovered-in-human-brains

by respinal • 6 years ago

183 128 6 years ago

npr.org

cgriswald• 6 years ago

The bike example is interesting because I remember learning how to ride a bike. I remember lots of details which others can confirm. But my perspective is external to my past self and I’m free to meander about in the memory, pause it, etc. It’s not particularly movie-like. I have a difficult time dipping into a first person perspective. And despite the article’s suggestion, even though I remember a spill in some detail (although in that case it’s more like a first-person snapshot than a movie) and although I know there was pain, I don’t remember the pain, just the fact of it. I do remember the feeling of anger and frustration as a result of the fall.

Anyway, anyone who found the article interesting might be interested in Moonwalking with Einstein: The Art and Science of Remembering Anything by Joshua Foer. In the book, Foer talks about his experiences with memory championships and fills that in with information about then-current understanding of human memory.

The place I learned to ride a bike is a place I know very well and I’ve used it as a memory palace. I wonder if doing that has somehow modified the perspective on that particular memory. I certainly have other memories which are episodic. Or maybe it’s just so far back in my past and I’ve reconstructed it enough times that it’s not quite as personal or visceral.

hellectronic• 6 years ago

I read the book and can recommend it. Very interesting!

danwills• 6 years ago

Even just the idea that there are specific cells for this is fascinating, and the fact that they change their 'tick' speed based on mood/interest? I should read the paper!:

https://www.pnas.org/content/early/2020/10/26/2013250117

notRobot• 6 years ago

Memory is a crazy thing. What I find particularly interesting is that some people recall memories in first person, and others in third person. Baffling.

apples_oranges• 6 years ago

I never thought about this, but if there's two ways to remember events there's probably also three, four.. or more?

hhjinks• 6 years ago

All my memories have George Clooney in the role as me.

carapace3• 6 years ago

Yes.

There's a whole field of study (often decried as pseudoscience) of the structure of subjective experience called Neurolinguistic Programming. Within it there's a constellation of concepts and techniques around deliberately altering your subjective experience.

For example, the first person / third person difference is referred to as "associated" / "disassociated" in the NLP jargon, and you can change which "mode" you use for a given memory and that will (typically) change the subjective effects of the memory.

You can use this to e.g., fall in(out) of love with someone. Recall all the good times with that person in associated(disassociated) mode and all the bad times with that person in disassociated(associated) mode and it will (typically) have a profound effect on your feeling towards that person.

Neat, eh?

There's a whole body of work around manipulation of time-coding. Some people see e.g. the past to the left and the future to the right,while others have the past behind them and the future ahead of them. Those are just two common styles of "timeline". Changing your time-coding can have profound effects on your psychology.

The real information revolution has only just begun and it doesn't have a lot to do with tiny transistors, if you catch my drift.

hackinthebochs• 6 years ago

All my childhood memories are in the third person. But I'm not sure if its due to the influence of pictures from those eras influencing how I visualize the memory or that its intrinsically third-person.

nihilius• 6 years ago

Just want to mention here that people exist wich can’t recall a memory trough mental images. It’s called aphantasia. https://en.wikipedia.org/wiki/Aphantasia

wongarsu4• 6 years ago

I can't really relate to the article's description of episodic memory. I'm also aphantastic. I wonder if there is a correlation or if it's just coincidence.

These things are surprisingly little studied, for example aphantasia has only really seen scientific interest in the last ten years. We all seem to assume that everyone's experience is the same as ours, only slowly discovering how untrue that really is. Even something "obvious" like colour blindness in only known for about 250 years.

scollet• 6 years ago

This has been particularly interesting to me because I can usually only relate to system design in software visually.

It works wonders for me personally to see code blocks as literal blocks that do X and connect to other blocks via graph edges. Then I pseudocode what I want and replace.

Whiteboarding is a bit difficult if I can't visualize transformations or stores of data in some way, or if I can't see a theoretical big picture for a particular function.

Spare_account• 6 years ago

Not long after finding out about Aphantasia I found out about Severely Deficient Autobiographical Memory (SDAM) which I felt described my experience of life very well.

SDAM isn't a recognised 'condition' as such, but it has a subreddit with some active users to compare your experiences with which you may find useful.

https://old.reddit.com/r/SDAM/

senectus1• 6 years ago

huh... I dont have any movie like memories... is this something I should be concerned about?

jchw• 6 years ago

I don’t think so. If you don’t have any memories that are visual at all, you probably just have aphantasia.

Tarq0n2• 6 years ago

I was under the impression that aphantasia had to do with a general lack of visualizing ability / visual imagination.

Tarq0n2• 6 years ago

There are individual differences in autobiographical memory [1]. I don't have any memories like this either.

[1] https://pubmed.ncbi.nlm.nih.gov/29807853/

jug• 6 years ago

Yes, I mean I can certainly vaguely visualize past moments in some 50/50 abstract/visual form I guess, but movie like... I'm unsure what they mean to be honest... and I'm sure that would be hard to explain as well. I guess I can see these "movies" mentally in the same way as how I vaguely remember the sequence of events in a recent dream. Unsure if I'd call that a movie though. Sounds like a pretty crappy one at that!

orbifold• 6 years ago

I always wondered this during meditation in high school: Do people actually see things when they close their eyes? The whole “you are at a beach, there is a gentle breeze...” never did anything for me. I can remember colors, relative positions, even how a specific place looked overall fairly well, but I don’t see anything.

Drakim2• 6 years ago

You likely have Aphantasia

https://en.wikipedia.org/wiki/Aphantasia

As for your question, yes! I don't need to actually close my eyes, I can think about certain things and see a vivid image of it deep inside of my mind.

If you need something to compare it to, can you actually hear music in your "mind" when you think about a song? It's kinda like that.

byteface2• 6 years ago

you ever had a dream?

scruple5• 6 years ago

I have aphantasia and I do not recall my dreams. Never have. I tried various dream recall techniques over the years. Nothing worked.

yesenadam6• 6 years ago

I guess this is a different thing, but...

When I was a kid I read a book that said if before you go to sleep you think "I will wake up at Xam" (whatever time you want) then you wake up at exactly that time. Which is pretty weird! We can't do that when we're awake. It actually works, and I've never needed an alarm clock. For a few ultra-important days I used one, like catching a plane, but I was always awake before it went off.

I have no idea how it works.

artonge• 6 years ago

I do it to when I need to wake up early so my body is not "surprised" by the low amount of sleep. Works well I think. Do you calculate how many hours you will sleep ? Maybe the brain set some kind of a timer.

shannifin• 6 years ago

I heard this from someone who swore it worked for her too, but it has never worked for me. It must be a superpower! :)

csomar• 6 years ago

It's not a superpower. For me it's a combination of two: Urgency and having had enough sleep. If I have a flight, I almost always wake up 30 minutes before my timer go off; even if I didn't get enough sleep. If I have nothing important to do the next day, my brain will usually ignore the waking up part and carries on.

One thing I noticed is that in the last year I have been waking up just a few minutes before my alarm goes off. My postulation is the iPhone alarm sound. It's bizarrely painful that I think I'm waking up just before it to avoid hearing it.

rtx2• 6 years ago

Yup, have experienced it personally. I usually wake up few mins before the alarm goes off. Though not proven through science you know something is there.

Another thing I would like to add is that scientific community should be more open to test conventional wisdom.

boomboomsubban2• 6 years ago

Why do you think science has not researched this and found it largely to be true? Here's one article on the subject

https://www.sciencedirect.com/science/article/abs/pii/S10870...

basicplus22• 6 years ago

For those who this does not work..

Try tapping your forehead with forefinger while counting up to the time you want to wake up just before you close your eyes to go to sleep..

eg to wake at 6am...

tap six times while saying "1, 2, 3, 4, 5, 6"

Repeat 2 times, (3 times in total)

TheSpiceIsLife2• 6 years ago

There’s a term / name for this method.

Emotional freedom technique (EFT)?

mbStavola• 6 years ago

There is definitely something to this.

A similar phenomenon occurs on public transit-- waking up at (or just before) your stop. I found that if I've taken the trip at least once, I can wake up pretty much exactly when I need to. Nearly every other frequent commuter I've discussed this with has a similar experience.

I used to believe it was related to subtle audio/visual cues while unconscious, but it might just be a function of a sense of time.

yesenadam6• 6 years ago

Yeah, does seem more likely it's my brain knowing the time fairly accurately from the early morning light levels, bird song, traffic noises, temperature, smells in the air etc, and other cues I'm not consciously aware of, than that I have a timer, accurate to a few minutes over 9 or 10 hours, in my body.

andai• 6 years ago

We can't do that when we're awake

I started using a timer about ten years ago for mundane tasks (getting done a chunk of unpleasant work, or for cooking) and these days I'll get up from my desk to go check on the oven right before the timer rings.

It works regardless of the length of the timer, and even when I don't know exactly how many minutes it is (twisty analog oven dial).

I don't consciously know how much time is left, but somehow I do know when "it's time."

Haven't tested this on longer timescales (hours) though, but I did meet a guy who said he always knew what time it was because he used to work for a TV station doing the countdown til they go on air.

VBprogrammer• 6 years ago

If someone asks me the time I'll often respond without looking "about 2.30". Then after digging out my phone check and see it's actually "2.35".

eloisius6• 6 years ago

I have the exact opposite sense of time. I'm frequently several minutes late to meetings because I've completely lost track of time. I'm very cue-dependent, and with this everything-at-home lifestyle we've transitioned to, I often have split-second confusion that I'm just having lunch in the middle of the day and have to go back to work in a minute and not go take a shower like it's after dinner.

jorgesborges• 6 years ago

I worked in the culinary world for a long time and we called this our “oh shit!” timer — being caught up in some task to suddenly remember to open the oven at the perfect moment before something burns.

marakv2• 6 years ago

This happens a lot in hospitality. Most chefs I know (myself included), set a timer, then go back to the job just before the timer goes off.

kklisura• 6 years ago

Was it "The Power of Your Subconscious Mind" that you read, by any chance? I remember reading that there and applying it as well and it did kind of work. I've read that as kid as well, so maybe that has to do with something. I regard that books as a pseudoscience from today's time, but who knows.

yesenadam6• 6 years ago

No, it was a book for kids about time and measurement or something..in the early 80s.

davidn20• 6 years ago

Gary Halbert, one of the best copywriters of all time, uses a time method to check if his mind was sharp. He will guess at how much time has passed without looking at a clock. The closer he was to the real time the better.

elliekelly2• 6 years ago

That's interesting. I thought I had read that older people perceive time more slowly than younger people but I wonder if that can be overcome by keeping our sense of time-telling "calibrated" by periodically checking our accuracy.

Aperocky• 6 years ago

Yeah I had similar experiences.

If I want to wake up really early for something I think is important, even if I stay up late, I just need to tell myself to wake up at $time and it works.

skocznymroczny• 6 years ago

When I was a kid, we used to have a radio/tape/CD player with a digital clock on it. Whenever I looked at it, as in whenever my body thought it would be a good idea to check the time, it was always something like 11:11 or 16:16.

zabardasth• 6 years ago

Yes, I too am a fan of repdigits.

yesenadam6• 6 years ago

Maybe that's true, but when I hear people say they always look at their watches at 12:34 or such a thing, I suspect (because it never happened to me!) it's probably something akin to the Baader-Meinhof illusion, "where something that has recently come to one's attention suddenly seems to appear with improbable frequency shortly afterwards." There are many similar phenonema humans fall victim to, thanks to our cognitive biases - our brains not as good at certain things as we'd like to think.

You tend to only remember what seem those unusual times. And the more you freak out about it, and wonder what the hell's going on, the more you remember seeing them, and the more you look..

https://en.wikipedia.org/wiki/List_of_cognitive_biases#Frequ...

scruple5• 6 years ago

Or 12:34 or sometimes my birthday.

monster_group• 6 years ago

It is more likely that those are the instances you remember because they stand out as compared to other uninteresting instances. So you get the impression that the former happens more often.

secfirstmd• 6 years ago

Haha, I know that's weird but actually I've noticed that myself happening a lot - thought I might be the only one! :)

BlahGod420• 6 years ago

Likewise. It works for insane times too; I've woken up in as little as 3 hours when I desperately needed 8 hours. There's a bit of a computational alarm clock in our brains somehow.

tenaciousDaniel• 6 years ago

A couple of weeks ago I woke up in the middle of the night. My first thought was, it's 2:54am. I didn't have any visible clocks, so I looked at my phone, and it was 2:53am. I've had that happen multiple times. Very strange.

JoeAltmaier• 6 years ago

I noticed years ago when at a bus stop, I'd get impatient and antsy seconds before the bus arrived (on time). I figured it was my subconscious alarm clock.

L_226• 6 years ago

Curious if you play/ed a musical instrument? I learned violin as a child and also experience the same phenomenon you describe, but I always attributed it to some neural pathway that was created during musical training (i.e. reading sheet music).

aeternum• 6 years ago

Is it possible you are subconsciously waking up and looking at the clock (or doing it consciously at the time but just not remembering it)? Sleep generally triggers some unique memory suppression mechanisms.

yesenadam6• 6 years ago

No, I've never slept with a clock in my room.

rekabis• 6 years ago

My asleep brain can do the exact same thing, even with consistent sleep deprivation (although it gets increasingly difficult beyond a sleep deficit of twelve hours per week).

On the flip side, my awake brain is completely and totally time-blind. I can go _hours_ on a subject I am obsessing over, and think it’s been just thirty minutes. Asperger’s sucks.

IAmNotAFix• 6 years ago

Are we supposed to have non-movie-like memories about the past? I mean, other than remembering "knowledge" such as sentences or dates or numbers or geography, etc, it seems that all memory about my "actual life" is movie-like.

magicalhippo• 6 years ago

I remember both moments and "movies". Some memories are more like pictures, usually accompanied with emotions. Other memories are more like movies, where I visualize the events unfold.

I seldom remember what I dream, but when I do it's usually right before I wake up in the morning, and it feels like being in a movie. I often get aware that I'm dreaming and can control the movie (dream) to some extent. I can then get really annoyed when the alarm clock goes off before the exciting part is over.

wongarsu4• 6 years ago

I experience movie-like dreams, but not movie-like memories. Not just the imagery (which is obvious, I'm aphantastic), but my memories aren't episodic at all. I have a sense of happened-after relations, but those are different from experiencing things one after another.

Somewhat related, while I can't visualize memories I do visualize dreams. That would leave me to believe that dreams are fundamentally different (see also how the body has to seize many motor functions during dreaming, but we can use all of them during remembering).

lexicality2• 6 years ago

I would be very interested to see a study about how these cells function under ADHD, because as I'm sure any sufferer would tell you - our time perception is very very weird.

Loughla• 6 years ago

My experience is that it is much more difficult to focus on any individual task, but much easier to enter a 'flow' state with ADHD.

If I can manage to do 'thing a', I find that often, all the world falls away - regardless of what the thing is.

I also have a theory, completely unfounded and out of my own ass, that ADHD and other similar issues are just part of the spectrum that is autism. Any scientist want to confirm my personal belief?

sosodev• 6 years ago

From what I understand ADHD and Autism share some symptoms but ADHD isn’t part of the spectrum because the causes are different.

It’s generally understood that the effects of ADHD diminish as you get older but the effects of Autism do not.

2Gkashmiri• 6 years ago

So Jack reacher was not lying then. Good to know

sebastian_j• 6 years ago

very interesting discovery!

haolez• 6 years ago

When I was young, I received a serious blow to my head while playing soccer that broke my skull and caused all sorts of issues at the time. I've managed a full recovery, but in the days following the accident, I lost my intuition of time. It's difficult to explain: I knew, logically, that I had lunch before I had dinner - and I had memory of doing both - but I couldn't "feel" that lunch was before dinner. It's pretty hard to explain and it was pretty weird to experience, but this symptom faded away after a couple of days.

SpeckOfDust• 6 years ago

I kind of know what you mean. In my case, it was due a psychedelic substance. I vividly remember being inside, walking out in the street and opening the door to go out, in that order. Made me feel very confused because I knew that logically it could not have gone that way, yet that was the chronology in my mind.

KingFelix• 6 years ago

Trytpamines are such a great way to look at the brain! Disruption of time / space / body / mind. Robin Carhart-Harris has done some great work, MAPS, etc.

polytely• 6 years ago

I wonder if this is something that is going wrong in my brain lol. I have a hard time remembering when exactly things happened (to figure out in what year I started school I basically have to walk backwards through my memories keeping track of some kind of time marker like seasons, like traversing a linked list). I often joke that if I ever was a suspect in a criminal investigation it would be very difficult for me to provide an alibi. It feels like a lot of day to day memories don't get 'time-stamped' at all.

I always thought this mainly had to do with ADD related working memory problems, but maybe it's more of an episodic memory problem?

ekanes5• 6 years ago

I have this too, and would describe it exactly the same. I think this is common with ADD.

davidmurdoch• 6 years ago

I think that's normal and precisely the mechanism the article is referring to?

Not being able to recall the year something occurred if you don't reflect on that memory every so often seems "normal" as well.

eloisius6• 6 years ago

This sounds exactly how my sense of chronology works. I have to find time markers and work my way from those to arrive at when a related memory occurred. I'll frequently reference photos that I happen to know has some obscure clue in it like a shirt a family member was wearing because I knew they had that shirt when I went to X event, which I still have a ticket stub memento for, therefor it was Y date.

I always attributed this to being home schooled (really just kind of free-range unschooled) until I was 14. I feel like I'm missing a lot of date-significant markers like passing from one grade to the next that most people have.

floathub• 6 years ago

This title seems very misleading given the study described. They have found a correlation between some neurons firing in sequence and a list of words being spoken from memory. We don't have any concrete understanding of how memories are really encoded, stored, and recalled. Indeed, we don't even know if "encoded", "stored", and "recalled" are useful approximations for what's really going on in there. So suggesting that we have found some specific time keeping module seems awfully hand-wavy (at best) to me.

acrefoot5• 6 years ago

I thought we had discovered pacemaker cells over 20 years ago. I'd be very surprised if that didn't already factor into hypotheses of how episodic memory is ordered. Either this article is disingenuous, or neuroscience suffers from deep fragmentation that is hindering progress.

https://www.hhmi.org/news/researchers-discover-molecular-pac...

hombre_fatal• 6 years ago

Did you actually read both studies? If so, I don't see how you could have arrived at the conclusion that the time cell paper is a rehash of what you linked. They are talking about and focusing on entirely different things.

acrefoot5• 6 years ago

I hadn't read the paper, just the article. Which is primarily what I was commenting on. When I read "now researchers have identified cells in the human brain that make this sort of memory possible", I was lead to believe that NPR was suggesting that there weren't plausible mechanisms of timekeeping for episodic memory before now. Especially since they don't mention any other mechanisms, and Buzsáki (not a study author) and NPR together imply that people with hippocampal lesions who can't order events correctly are simply missing their time cells.

Anyhow, I've now read much more of the two linked papers, and some related papers.

In the 2011 paper linked from the NPR article, under "Neuronal Ensembles Signal Time, as well as Location and Behavior, during the Delay Period" (https://www.sciencedirect.com/science/article/pii/S089662731...) "time cells" are defined under their relation to "place cells". As far as I can tell, this paper coined the term. Now, in this paper, they aren't sure if the time cells are scalar time (Gibbon) or non-linear time (Staddon and Higa) or some combination of the two. Well, Gibbon's scalar expectancy theory for timing (SET) uses pacemaker cells in the theory. Now other papers do want to move away from pacemaker cells: Staddon and Higa point out that the "Weber law" that SET depends on doesn't scale well, so they have other theories. However, I could still imagine that pacemaker and timestamping neural circuits would work together, no?

This review article of timing in the brain seems helpful, though I don't have time to read it fully today: https://www.sciencedirect.com/science/article/pii/S089662731... It covers oscillators (pacemaker-accumulator/SET), ramping, and population clocks ("time cells" and other names). I find it problematic that the NPR article only focuses on one name for one possible explanation of the observed behavior. It makes for a nice article, and the metaphor of time cells and place cells are attractive. It doesn't leave

Time cells seem to invoke a chain of neurons firing, to encode events along the chain. I can believe that this orders events on the order of tens of seconds (the literature surveys from milliseconds to tens of seconds). But the NPR article suggests that the ordering of an entire tour of UCSD is also encoded in time cells. I doubt that there was one unending chain of ordering for that entire tour. Personally, I find that I have to reason about time on longer time scales, or I might mix up a recollection of how a story goes. (Once I tell a story a few times, I've learned a new skill--how to tell the story--so it becomes easier to recall a sequence I've chosen to highlight.)

acrefoot5• 6 years ago

Related: breathing is semi-autonomous, and controlled in the brain:

https://www.ucsf.edu/news/2017/08/408006/searching-brain-cel...

We can be aware of our breathing or not, yawn, and hold our breath. I imagine we can do similar with our sense of time: count seconds, have a sense of time, and lose our sense of time (on purpose or by accident).

SubiculumCode2• 6 years ago

The prior probability of you being wrong about facts in another field is fairly high.

The prior probability of the researcher being wrong about facts in their own field is much lower.

Therefore the default assumption one should have when reviewing research from a field that is NOT their own is closer to "I am the idiot" than "The researchers are the idiots".

in my humble opinion.

acrefoot5• 6 years ago

The years I've gone to SFN, I've been amazed at how fragmented the field is. People get into neuroscience from all sorts of places. Neurosurgery, C. elegans research, optogenetic studies, fmri studies, biochemistry: these approaches to neuroscience are often so different they don't know about the advances of the others.

meroes• 6 years ago

This isn't unique to humans or even animals

https://youtu.be/CA-YsWXRSHU?t=448

https://en.wikipedia.org/wiki/Arabidopsis_thaliana#Light_sen...

It records ~40 days of temperature in a certain range, and remembers it till it senses the light of spring. If it's put into a dark room after 40 days, it waits till it senses light to flower, so it must be remembering those memories of cold temperatures.

PIKAL• 6 years ago

In Sasha Shulgin’s book PIKAL, he describes mixing two drugs, I think it was MMA and cannabis, and experiencing perceived time dilation. He describes it as looking at the hands of a clock and experiencing much more time between the movement of the hands than one normally would. He said it was frightening, so he called his friend to come help. He was able to speak normally and hear people speak normally. While he was on the phone, he asked for a timer to be set while he went to go retrieve something. His experience of walking down the hall and back felt to him like twenty minutes. When he returned to the phone, he was told it had only been two minutes.

The effect wore off by the next day. He was never able to recreate the effect, but he kept a battery of experiments at the ready of it ever happened again. He expressed regret at not being able to carry them out.

He once said that the experience changed his perception of death. If time were to continue dilating, asymptotically approaching a halting of time, then one might never die in their own experience.

sixdimensional• 6 years ago

Ok, armchair theory here, let's for a moment assume Einstein's belief that time is the fourth dimension.

We use our senses to detect/experience dimensions, right? I mean, we use sight, hearing, touch to detect 3-D space, for example (not forgetting taste and smell too).

If time is the fourth dimension, maybe these cells are our evolutionary attempt to sense/detect and operate within that dimension.

Which explains how the experience of time travel could be possible in at least one way - if we can change/affect our sense/perception of time (um.. navigating time?), it can seem to us like time travel. I'm not saying we would be affecting the timeline itself in this case, I mean more like messing with the sense of time that causes us to "experience" time travel.

Ok sorry, that does too sound like too much armchair pseudoscience, but this article and some of the other comments just got me thinking.

'Time Cells' Discovered in Human Brains

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