[acrefoot]

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...

[acrefoot]

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).

[SubiculumCode]

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.

[acrefoot]

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.

[SubiculumCode]

Should have gone to HBM I guess ;) I suppose my comment was a bit strong. My Ph.D was on the the hippocampus and the development of binding operations supporting episodic memory using standard MRI and cognitive tasks, and I already know I don't understand half of what they are doing in more basic neuroscience articles.

[acrefoot]

No worries!

I have no problem with the paper authors. Most of the authors on the paper come from neurosurgery/neurology, and I don't doubt for one second that they have a strong grasp of "I can mess with the human brain in these ways and I'll get these behaviors". They shouldn't be expected to know everything we've ever looked at for time in the brain.

I am frustrated at one of the ways science journalism tends to report on neuroscience. I think they want to do it like they do physics, and it affects how people outside the field think. Rather than considering the brain as a complex system, we're looking for the Jennifer Anniston neuron, or time cells, or some single component that explains consciousness, much like we looked for the "god particle" (Higgs) or gravitational waves. It's not a great way to look at things.

My original comment on fragmentation is just my own opinion. Maybe it's not as much of a barrier as I think it is.

[hombre_fatal]

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.

[acrefoot]

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.)