6 ms·

How the Brain Creates a Timeline of the Past

188 points by chmaynard 8y ago

noobiemcfoob 8y ago
"Just a few months after Howard and Shankar started to flesh out their theory, other scientists independently uncovered neurons, dubbed “time cells,” that were “as close as we can possibly get to having that explicit record of the past,” Howard said. These cells were each tuned to certain points in a span of time, with some firing, say, one second after a stimulus and others after five seconds, essentially bridging time gaps between experiences." Most relevant idea from the article for me
ausbah 8y ago
Are there any research groups who are actively investigating how insights into the human mind may be applied to artificial intelligence methods? If that's even applicable? Edit 0: I should clarify that I am well aware that neuron architecture already has influenced modern AI methods, I was leaning more towards non-neuron based methodologies.
- vox17 8y ago
  Neural networks has greatly been influenced by insights into the human mind. Hence, also why it's called "neural". So yeah there are research groups actively into this :D Usually, researchers at universities.
- jimfleming 8y ago
  Numenta is probably the most direct / well-known example of what you're asking. They get mixed reactions from the community (some fair, some not). DeepMind occasionally publishes crossover papers from neuroscience (e.g. grid cells; metalearning). Lots of other groups are looking at neuroscience for applications to ML too like University of Washington and Columbia.
- jplayer01 8y ago
  This is what everybody has been working on for the past ten years.
- jk4930 8y ago
  "Biologically Inspired Cognitive Architectures" and they have some overlap with the AGI (AI at human level and beyond) folks as well. http://www.bicasociety.org/ http://www.bicasociety.org/
jimfleming 8y ago
Hopefully this leads to better temporal priors for machine learning models. Sequence encoding frequently uses position coding[0] but the typical approaches (e.g. low frequency sin waves) are fairly naive. In reinforcement learning we have (somewhat obvious) works that show that providing explicit time representations help[1]. Simply throwing a recurrent model at a sequence may pick up simple ordering but improving the temporal representation would improve data efficiency. [0] https://arxiv.org/abs/1706.03762 https://arxiv.org/abs/1706.03762 [1] https://arxiv.org/abs/1712.00378 https://arxiv.org/abs/1712.00378
rconti 8y ago
We know that entering a new room in your house impacts your thinking -- like a new "window" of thought opens. There is, in fact, a concrete reason why you will forget what you were looking for as soon as you enter the room you intended to search for said object. It's interesting, as mentioned, how you can recall other things that happened in temporal or spatial proximity to another memory you're recalling. My mother has an uncanny ability to unwind a series of connected memories -- "I know that was in 1973 because that's when so-and-so got married, and we had traveled to such-and-such location that year, which is why I had the new suitcase that..." Fascinating research.
chdaniel 8y ago
Maybe a bit unrelated but I thought of this as I was reading through the article: I think it'd be very interesting to invest in a dreams research centre and I'll definitely do so as well eventually
empath75 8y ago
Lots of people have suggested time distortion effects from psychedelics have to do with altering how this system works -- if time input decays more slowly, that would explain things like visual trails and so on.
ralusek 8y ago
I actually think it's much simpler than all of this. I may be extrapolating from my own brain a bit, I'm fairly certain that the brain creates a timeline of the past by running a garbage collection function every night that goes something like: if (memory.timestamp < YESTERDAY) delete(memory);
- vokep 8y ago
  I think its a bit more complex than that, maybe something like if (memory.timestamp < YESTERDAY && memory.significance < 0.1) { delete(memory); } else { dream_playback(memory).then((score) => { memory.significance = score; }) }
  - therein 8y ago
    So if I understand correctly, you are suggesting that the dream playback is used as a way to determine the significance of a memory?
galaxyLogic 8y ago
As a programmer I think I forget a lot because programming keeps my brain busy thinking about things. I forget features and solutions I've done before. I think it's because the space inside the brain is limited. I'm thinking hard about a new problem every day. Whereas my boss can remember things I did a year ago I can't easily.
- 9dev 8y ago
  Maybe its just you being in the business longer than me, but I've had pretty much the opposite thought: I'm learning new stuff every day, wondering when I will start to actually forget chunks of it. Currently, it seems like most technical knowledge tends to stick in my brain, with no apparent limit yet. I can still recall most of the Redis protocol commands despite not having used it in more than six years.
  - pandapower2 8y ago
    After almost 20 years as a commercial developer I forget entire projects, entire jobs even. Someone will mention a company name and it takes me a few seconds to realize that the reason the name is familiar is because I briefly worked there 15 years ago. Jobs I held for multiple years are fine but any short stints are a blur.
    - sizzle 8y ago
      I've experienced this as well and the phenomenon is more pronounced if the role/company was unremarkable at the time, and it was as if I overwrote the memory with the excitement of the next job, then rinse and repeat with every new job.
      - galaxyLogic 8y ago
        I guess something like that is going on in my brain too. The code I come up with often feels exciting because it is a solution to a problem, but then the next several 100 code-solutions overwrite the memory of what once felt important. It is no longer important, so I think it's good my brain let's go of it. But often I lament having not much documented why I wrote some code the way I did
nshm 8y ago
The journalist failed to explain "Laplace transform" part unfortunately. How something like complex variable operation happens in the brain. Most likely the original researchers meant something different.

188 points by chmaynard 8y ago

"Just a few months after Howard and Shankar started to flesh out their theory, other scientists independently uncovered neurons, dubbed “time cells,” that were “as close as we can possibly get to having that explicit record of the past,” Howard said. These cells were each tuned to certain points in a span of time, with some firing, say, one second after a stimulus and others after five seconds, essentially bridging time gaps between experiences." Most relevant idea from the article for me

ausbah 8y ago

Are there any research groups who are actively investigating how insights into the human mind may be applied to artificial intelligence methods? If that's even applicable? Edit 0: I should clarify that I am well aware that neuron architecture already has influenced modern AI methods, I was leaning more towards non-neuron based methodologies.

vox17 8y ago
Neural networks has greatly been influenced by insights into the human mind. Hence, also why it's called "neural". So yeah there are research groups actively into this :D Usually, researchers at universities.
jimfleming 8y ago
Numenta is probably the most direct / well-known example of what you're asking. They get mixed reactions from the community (some fair, some not). DeepMind occasionally publishes crossover papers from neuroscience (e.g. grid cells; metalearning). Lots of other groups are looking at neuroscience for applications to ML too like University of Washington and Columbia.
jplayer01 8y ago
This is what everybody has been working on for the past ten years.
jk4930 8y ago
"Biologically Inspired Cognitive Architectures" and they have some overlap with the AGI (AI at human level and beyond) folks as well. http://www.bicasociety.org/ http://www.bicasociety.org/

jimfleming 8y ago

Hopefully this leads to better temporal priors for machine learning models. Sequence encoding frequently uses position coding[0] but the typical approaches (e.g. low frequency sin waves) are fairly naive. In reinforcement learning we have (somewhat obvious) works that show that providing explicit time representations help[1]. Simply throwing a recurrent model at a sequence may pick up simple ordering but improving the temporal representation would improve data efficiency. [0] https://arxiv.org/abs/1706.03762 https://arxiv.org/abs/1706.03762 [1] https://arxiv.org/abs/1712.00378 https://arxiv.org/abs/1712.00378

rconti 8y ago

We know that entering a new room in your house impacts your thinking -- like a new "window" of thought opens. There is, in fact, a concrete reason why you will forget what you were looking for as soon as you enter the room you intended to search for said object. It's interesting, as mentioned, how you can recall other things that happened in temporal or spatial proximity to another memory you're recalling. My mother has an uncanny ability to unwind a series of connected memories -- "I know that was in 1973 because that's when so-and-so got married, and we had traveled to such-and-such location that year, which is why I had the new suitcase that..." Fascinating research.

chdaniel 8y ago

Maybe a bit unrelated but I thought of this as I was reading through the article: I think it'd be very interesting to invest in a dreams research centre and I'll definitely do so as well eventually

empath75 8y ago

Lots of people have suggested time distortion effects from psychedelics have to do with altering how this system works -- if time input decays more slowly, that would explain things like visual trails and so on.

ralusek 8y ago

I actually think it's much simpler than all of this. I may be extrapolating from my own brain a bit, I'm fairly certain that the brain creates a timeline of the past by running a garbage collection function every night that goes something like: if (memory.timestamp < YESTERDAY) delete(memory);

vokep 8y ago
I think its a bit more complex than that, maybe something like if (memory.timestamp < YESTERDAY && memory.significance < 0.1) { delete(memory); } else { dream_playback(memory).then((score) => { memory.significance = score; }) }
- therein 8y ago
  So if I understand correctly, you are suggesting that the dream playback is used as a way to determine the significance of a memory?

galaxyLogic 8y ago

As a programmer I think I forget a lot because programming keeps my brain busy thinking about things. I forget features and solutions I've done before. I think it's because the space inside the brain is limited. I'm thinking hard about a new problem every day. Whereas my boss can remember things I did a year ago I can't easily.

9dev 8y ago
Maybe its just you being in the business longer than me, but I've had pretty much the opposite thought: I'm learning new stuff every day, wondering when I will start to actually forget chunks of it. Currently, it seems like most technical knowledge tends to stick in my brain, with no apparent limit yet. I can still recall most of the Redis protocol commands despite not having used it in more than six years.
- pandapower2 8y ago
  After almost 20 years as a commercial developer I forget entire projects, entire jobs even. Someone will mention a company name and it takes me a few seconds to realize that the reason the name is familiar is because I briefly worked there 15 years ago. Jobs I held for multiple years are fine but any short stints are a blur.
  - sizzle 8y ago
    I've experienced this as well and the phenomenon is more pronounced if the role/company was unremarkable at the time, and it was as if I overwrote the memory with the excitement of the next job, then rinse and repeat with every new job.
    - galaxyLogic 8y ago
      I guess something like that is going on in my brain too. The code I come up with often feels exciting because it is a solution to a problem, but then the next several 100 code-solutions overwrite the memory of what once felt important. It is no longer important, so I think it's good my brain let's go of it. But often I lament having not much documented why I wrote some code the way I did

nshm 8y ago

The journalist failed to explain "Laplace transform" part unfortunately. How something like complex variable operation happens in the brain. Most likely the original researchers meant something different.