Sometimes you see weird things on Fedi, like this conversation between Rats (scientists)

Source:
https://neuromatch.social/@adredish/115848409406193646

#Neuroscience #NeuroRat

The 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)

#Alzheimer #Dementia #Aging #Neuroscience #NeuroRat

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

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!

#SpatialCognition #NeuroRat #Navigation

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?

#Neuroscience #NeuroRat #NeuroHuman

#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!

#LeutgebLab #NeuroRat #Neuroscience #SpatialCognition

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??

#Hippocampus #NeuroRat

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??

#Neuroscience #NavigationStrategies #theta #swr #NeuroRat

#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)

#JournalClub on Closed-loop modulation of remote hippocampal representations with neurofeedback, from #FrankLab: little summary + comments.

• The goal is to see if rats can deliberately reactivate internal representations, without external cues.
• The authors design a closed-loop system that does clusterless real-time decoding of position and rewards the rats when they reactivate a specific maze arm end.
  
• The rats go through a gradual training process: first getting reward on the actual maze (a T-maze), then getting reward in the home box when they orient towards the target arm of the maze [head-direction task], then getting reward in the home box when they reactivate the representation of the target maze end [neurofeedback task].
• The rat's performance is not too bad given the difficulty of the task, kudos to Rat2 who seemed to really know what he was doing.
• interestingly, the reactivations do not happen during #SharpWaveRipples, and not really during theta either, just during an uncharacterised LFP state.
• Little caveat 1: as far as I can see, the head-direction of the rats is not shown in any plot and it is not possible to say if the rats might still be doing the head-direction task during the neurofeedback task. That being said, the rats clearly reactivate the target arm more in the neurofeedback than head-direction task, which is quite convincing.

• Little caveat 2: the performance is always shown in terms of total rewards collected, and not reward rate. So in different sessions rats might reach the maximum reward but take twice the time. Showing reward rate would be more informative.

• conclusion: this is pretty cool, but we would really need to know about the head-direction.

• question for the audience: what do you think the rats "think about" during those reactivation moments??

#Neuroscience #HippocampalReplay (not really) #ThetaSequences (not really) #PlaceCells #NeuroRat #Hippocampus

It's always nice when you finally finish #SpikeSorting an old recording session and find many #PlaceCells (here, 101) 🥰

I also recently implemented a way to remove putative duplicate recordings (when spikes from the same neutron are detected in two different tetrodes) and there can be a surprisingly high amount, 6-10 % of cells as far as I can see, this is with bundles of 8 tetrodes.

#Hippocampus #Neurorat #Hexamaze

Ok maybe this is the best cluster space ever
(also, from an implant that’s almost 4 months old!)
#Tetrodes #NeuroRat #Hippocampus #PlaceCells

I bet you’ve never seen a bigger… cluster than my one 😁
(Well, technically, my #NeuroRat’s)
#Hippocampus #Tetrodes

If a #NeuroRat running in a maze hears one of his #PlaceCells activating (from the computer) as he enters a specific location… does the sound become a cue??? 🤯

#Hippocampus #Navigation #Neuroscience

Did you know that Rats, like wizards, can sleep with their eyes open?
#GandalfTheRat #NeuroRat

Best sounds for falling asleep?
Tired: sounds of rain 🌧️
Wired: sounds of rat brain 🧠
Inspired: sounds of sleeping rat brain 💤

#Hippocampus #NeuroRat #HippocampalRipples

Edit: re-added alt text which had disappeared for some reason

@BlakeP_Neuro I think I got the same as you, but in #Hippocampus!!
#Tetrodes #NeuroRat

Here is some very nice #ThetaRhythm from the #MEC (hopefully) of a female #NeuroRat

(source: Roddy Grieves; filtering: 1-600 Hz; spans 2s)