El DuvelleSometimes you see weird things on Fedi, like this conversation between Rats (scientists)
Source:
https://neuromatch.social/@adredish/115848409406193646
El Duvelle NeuroThe world of rat models of Alzheimer's disease is proving to simultaneously be much more complex, and much smaller, than I had anticipated.
Apparently, rats are better than mice for comparing with humans, but the large majority of the research is done on mice models.
Also, apparently, much of the existing rat models are not optimal for what I would like to do (appetitive spatial tasks) for different reasons.
So I'm still looking for as much input as possible from people doing research with AD rat models who could point to one that mimics the memory deficits observed in humans 🙏🧠
(My previous post about this:
https://neuromatch.social/@elduvelle_neuro/115107318934779142)
El Duvelle Neuro (@[email protected])
What are "good" models of Alzheimer's disease in rats? Ones that mimic the memory impairments seen in humans? I know most people use mice models but are there any labs out there that have rat models? #alzheimers #NeuroRat #Hippocampus #Memory
What are "good" models of Alzheimer's disease in rats? Ones that mimic the memory impairments seen in humans?
I know most people use mice models but are there any labs out there that have rat models?
I contributed a little bit to this methods paper now published in #eNeuro :
Adapt-A-Maze: An Open-Source Adaptable and Automated Rodent Behavior Maze System - my contribution is mostly about the automated, pneumatic door system, as you may know, doors are my thing 😉 🚪
First author Blake Porter from the #JadhavLab did a great job putting everything together in an easily-useable format and, for once, I will link to Bluesky with his nice thread on it: https://bsky.app/profile/blakep-neuro.bsky.social/post/3lms56kaj3k2x
If you ever try to implement it in your own lab, let me know!
Here's a short but related 'forum' about exactly this:
Why do primates have view cells instead of place cells?
"if primates are tested in conditions where visual information is scarce, place cell-like representations may emerge."
#MartinezTrujilloLab #Neuroscience #NeuroRat #NeuroPrimate #PlaceCells #ViewCells
Thinking about #PlaceCells and the #Hippocampus, do you think results in rats (/rodents) generalise well to humans, and conversely?
Yes, good generalisation between the species
No, poor generalisation between the species
It depends (on what?)
I don't know / see results
Poll ended at .
#NeuroESC #JournalClub
Reading Mental exploration of future choices during immobility theta oscillations
If you've read it, will you let me know what you think?
The authors look at #ThetaSequences in a working memory task in a radial arm maze. They find theta during immobility (makes sense, e.g. we saw that in our two-goals task). They also find that theta sequences might preferentially represent the next goal (also makes sense, e.g. Hippocampal theta sequences reflect current goals)!
I have only done a quick reading so far, but am confused by a few points:
- the decoding is done on all cells (pyramidals and interneurons), shouldn't it be done on pyramidal or #PlaceCells only?
- the cell counts are quite low (often less than 40 pyrs) when I would have thought at least 50 place cells would be needed for this kind of maze. I guess that shows that #Neuropixels are not the best to record from dCA1!
the decoded algorithm itself includes a ' position transition matrix' which seems like it would bias decoding towards realistic trajectories that the rat is about to do??? (but I probably missed something)
also, this study is very related to this other paper, which is not discussed or even cited (😕 ):
Assembly Responses of Hippocampal CA1 Place Cells Predict Learned Behavior in Goal-Directed Spatial Tasks on the Radial Eight-Arm Maze #CsisvariLab
Let me know what you think!
Mental exploration of future choices during immobility theta oscillations
Mental exploration enables flexible evaluation of potential future choices, guiding decision-making without requiring direct real-world iterations. Although the hippocampus is known to be active while imagining the future, the precise mechanisms that support mental exploration of future choices remain unclear. In the hippocampus, the theta rhythm (4-12 Hz) is prevalent during movement and supports memory coding during real-world exploration by organizing neuronal activity patterns into short virtual path segments (theta sequences) around the rat’s location. We observed these theta-related neural activity patterns during movement in a hippocampus-dependent working memory task and also, unexpectedly, theta oscillations and theta-related neural activity during immobility. Compared to standard theta sequences during movement, theta sequences during immobility differed in that they occurred at a shifted theta phase and preferentially represented remote locations, in particular the next choice in the working memory task. Coding for future locations was also observed during awake sharp wave ripple, but these short-lasting events occurred rarely and were biased toward frequently visited locations. Therefore, our findings suggest that recurring bouts of theta oscillations during immobility, which are also observed in primates and humans, support the cognitive demands of mental exploration in the hippocampal network and facilitate ongoing predictions of future choices. ### Competing Interest Statement The authors have declared no competing interest.
This paper ⬆️ from Caitlin Mallory is now out in Science! Great to see a #HippocampalReplay paper there, and very well deserved!
The time course and organization of hippocampal replay
From #FosterLab, maybe soon the #MalloryLab??
My latest #Neuroesc #JournalClub was on this:
Rat anterior cingulate neurons responsive to rule or strategy changes are modulated by the hippocampal theta rhythm and sharp-wave ripples
I won't do a super-long summary like last time, but please share your thoughts if you've read it!
The author line-up is quite interesting, I think they were all students at the time of data collection which seems to have happened a long time ago, and now many are PIs (@BenoitGirard probably knows about the backstory...)! Probably a pandemic paper??
The scientific question (what supports rule recognition and strategy shift) is really interesting, and they record in the frontal cortex (#ACC) as well as #Hippocampus (ventral CA1!), but the rats just were not up to the task (1/5 rats actually did what they wanted). I am also not fully convinced by some of the analysis. @jessetm I'd be interested to know what you think of their strategy detection method!
Why is it that all papers looking at these themes always end up being.. quite complex??
#Tetrode recordings (in a bundle): did you know that you could record the same neuron on two different tetrodes?
or even three different tetrodes??
After checking that, turns out I usually have about 5-10% of neurons that are a duplicate of another neuron, in a given 8-tetrodes recording! They are pretty easy to detect with a firing rate correlation so I can remove them from analysis.
But I bet most neuron counts in published papers are inflated of that much!
Here's an example where you can see the spike plots and waveforms of 3 different, well-isolated clusters, recorded from 3 different tetrodes!
#Hexamaze #NeuroRat #Neuroscience #Ephys #Hippocampus #PlaceCells #SpikeSorting (-related)
