Simply remembering an event can trigger theta oscillations.

https://news.arizona.edu/story/new-uarizona-study-links-brain-waves-directly-memory

Paper: https://www.cell.com/neuron/fulltext/S0896-6273(23)00474-9

#CognitiveNeuroscience
#Neuroscience
#Hippocampus
#Memory

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Study identifies #gene conferring novel function to #seahorse brood pouch.

#flame_cone_cells #pgrich #Hippocampus

https://phys.org/news/2023-07-gene-conferring-function-seahorse-brood.html

Scientists find the Source of a mysterious #brain wave that could boost #memory and #creativity 👇🤔🧠

https://singularityhub.com/2023/07/23/scientists-found-the-source-of-a-key-brain-wave-for-memory-and-creativity/

#cognition #waves #hippocampus #neurons #frequencies

👍 When we #walk.

“it (#BDNF, ed.) goes into the bloodstream and is one of the few substances that can pass the barrier up to the brain, where it affects our hippocampus and makes that part of the brain grow.

»We have always heard from people that they get these feelings when they move, but now we are beginning to understand why«”.

(translated from Danish to English by Bing)

#health #walking #hippocampus
https://www.berlingske.dk/samfund/vi-glemmer-hvor-nemt-motion-kan-vaere-mange-tjekker-ud-naar-vi-taler-om

Want to learn more about #microglia / #synapase interaction in the #hippocampus during and after #stress? Join me at my poster T11-079B at the #gliameeting in #Berlin today 😊
@dzne #GLIA2023 #gliameeting #majordepressivedissorder #depression

Impact of social isolation on grey matter structure and cognitive functions: A population-based longitudinal neuroimaging study

Social isolation contributes to human brain atrophy and cognitive decline, indicating an opportunity to reduce dementia risk by promoting social networks.

#Neuroscience #Brain #Neurology #NeurologicalDiseases #NeurodegenerativeDiseases #Neurodegeneration #Alzheimer
#CognitiveDecline #CognitiveDysfunction #Dementia #Hippocampus #Neuroimaging #NeuroImage #SocialIsolation #SocialBond
#Biomedicine #Health

https://elifesciences.org/articles/83660

Social Bonds Protect Aging Brains

Social isolation can potentially harm brain structure and cognitive performance, suggesting an increased risk of conditions like Alzheimer’s dementia.
A lack of quality social interaction can lead to a decrease in the hippocampus’s volume, crucial for memory formation and retrieval, and poorer cognitive performance.

#Neuroscience #Brain #Neurology #NeurologicalDiseases #NeurodegenerativeDiseases #Neurodegeneration #Alzheimer
#CognitiveDecline #CognitiveDysfunction #Dementia #Hippocampus #Neuroimaging #NeuroImage #SocialIsolation #SocialBond
#Biomedicine #Health

https://neurosciencenews.com/social-aging-neuroscience-brain-23505/

Where imagination lives in your brain https://www.scientificamerican.com/article/where-imagination-lives-in-your-brain/ "there is absolutely no way you can imagine anything without the past"; #hippocampus #aphantasia

@marcia_petyt Tagging as #neuroscience #hippocampus #sleep #DeepBrainStimulation

“we implemented real-time closed-loop deep brain stimulation in human prefrontal cortex during sleep and tested its effects on sleep electrophysiology and on overnight consolidation of declarative memory.”

Where do phobias come from? | BBC Ideas

https://www.youtube.com/watch?v=zmPzvWoE5Xk

#phobia #psychology #amydgala #hippocampus #hypothalamus #fear

#Rat #MentalMap #Hippocampus

https://www.biorxiv.org/content/10.1101/2023.04.07.536077v1

@eLife

Nice video of neuronal activity!

"Microglial motility is modulated by neuronal activity and correlates with dendritic spine plasticity in the hippocampus of awake mice"
Nebeling et al. 2023 https://elifesciences.org/articles/83176

Editor evaluation: "This work provides insights into the use of anesthetics in measuring cellular dynamics, regional differences in plasticity, and neuronal activity regulation of microglia dynamics. It is an important contribution to understanding hippocampal microglia plasticity in adulthood."

#neuroscience #microglia #neurons #mouse #hippocampus

@TrackingActions Excellent dispatch! Let's tag with #neuroscience #GridCells #hippocampus so it appears on those who follow this tags, and also becomes easier to find in the future.

Here are some #PlaceCell clusters for you (#Tetrode recordings) 😃​
#Hippocampus

Any of you #Rat #Hippocampus researchers have a pic /screenshot / schematic of a sleep #Spindle in cortex or hippocampus? Actually can you see them in hippocampus? 🙏​
( @BlakeP_Neuro might?)

RT @obarnstedt
🚨🚨🚨PREPRINT ALERT🚨🚨🚨
We used dual-colour in vivo #two-photon #imaging and #optogenetics to learn what information the #brain’s dorsal #hippocampus sends to #NucleusAccumbens while mice navigated to a learned #reward site. What did we learn…? A🧵1/25 https://doi.org/10.1101/2023.03.09.531869

🔥​​🔥​🔥​ PREPRINT ALERT 🔥​🔥​🔥​
https://doi.org/10.1101/2023.03.09.531869
We used dual-colour in vivo #twophoton #imaging and #optogenetics to learn what information the #brain ’s dorsal #hippocampus sends to #NucleusAccumbens while mice navigated to a learned #reward site. What did we learn…?

While we often like to think of memories as abstract mental states, they actually serve a key role for our survival and that of our ancient ancestors: Remember where there’s a dangerous place and you can avoid it; remember where there’s food and you won’t go hungry.

But how do we go from the memory of a food location to actually approaching it when we’re hungry? We know that dorsal hippocampus (dHPC) is one of the main “memory storage” sites in the brain and important for navigation, but who sits on the receiving end of this information?

Many great colleagues (like @stpntr@twitter.com, @marisosa @lukesjulson@twitter.com,…) have highlighted the role of projections into the nucleus accumbens (NAc), part of the basal ganglia (BG). The BG’s role revolves around action selection, while the NAc largely deals w/ reward processing.

So we know that this dHPC>NAc pathway is needed for linking rewards with locations, but what does the HPC actually tell the NAc? What would we see if we could listen in on their private conversations? As it turns out, this is technically quite challenging because we need to combine cell identity (NAc-projecting or not) with cell activity. To achieve this, we turned to dual-colour two-photon calcium imaging. We labelled NAc-projecting neurons in red and used a pan-neuronal green calcium indicator to see live neural activity in dHPC.

We trained mice to lick in a reward zone on a cued linear treadmill to receive condensed milk which they absolutely love. After 5 days, they expertly slowed down and licked ahead of this reward zone, showing us they learned this space~reward association.

So what happens inside dHPC while mice navigate to this reward location? We hypothesised that either dHPC>NAc cells would be mostly active at the reward zone, or that they would show no spatial bias. As it turned out, neither were true…

Instead, we found that dHPC>NAc neurons showed stronger spatial tuning compared to those dHPC neurons projecting elsewhere (dHPC-). They were also more strongly modulated by the texture cues we provided, suggesting privileged spatial information routing to the NAc.

What about the reward zone though? Many previous studies found place cells clustering near reward zones. When we first looked at the data, we saw little evidence of this (sad emoji), but we noticed some mice performed better than others. When we separated high- from low-success trials, we could see the reward zone being overrepresented by place cells – this effect was particularly pronounced for dHPC>NAc neurons. We could also show that these projection neurons are better at decoding the spatial location ahead of the reward zone.

This suggests that it may be less the sensory environment that determines neural coding but the behaviour with which the mouse engages with it. This is a realisation that has swept across the neurosciences: neural activity in most brain regions seems modulated by behaviour.

Better performance usually goes in hand with deceleration as mice approach the reward zone. So do neurons “care” about speed? We found neurons that were either positively (acceleration) or negatively (deceleration) modulated by speed, as others before us. Interestingly, negatively speed-modulated neurons were overrepresented in the dHPC>NAc population, suggestive of a role in reward approach. To actually obtain the reward, mice not only needed to remember the reward zone but also needed to lick there. Strikingly, we saw that dHPC>NAc neurons became very active around the time of appetitive (but not consummatory) licking. Also, if we zoom in on the activity of individual neurons, we saw a larger proportion of dHPC>NAc neurons tuned to appetitive licking.

Does this mean that dHPC>NAc projections could “guide” the mouse’s lick activity, or do they simply receive a motor signal from elsewhere? To test this, we optogenetically activated excitatory dHPC axons in NAc after mice learned to lick for rewards.

We found that upon stimulation of this projection, mice actually started to engage in appetitive licking. This suggests that dHPC>NAc projections seem to indeed be in the driver’s seat for reward-seeking behaviours.

How can we reconcile this with our previous findings of enhanced spatial and (negative) velocity tuning? Are there separate populations for each of these aspects or do we have “multi-tasker” neurons that can do it all?

Answering this question is not trivial because, as mice approached the reward zone (space), they tended to slow down (speed) and start licking, resulting in a lot of “collinearity” in the behavioural data. To tackle this, we built computational models (GLMs) to predict neural activity based on space, speed, and lick data. We then randomly shuffled each behavioural variable to see if our models got worse. With this approach, we found that indeed dHPC>NAc neurons were more heavily tuned to space, speed, and licking, but we also found many neurons that encoded multiple behavioural features. Indeed, among the dHPC>NAc population, this seemed to be the norm rather than the exception. We tend to cherish those one-on-one relationships like position~activity (place cells) or speed~activity (speed cells), but computationally, such mixed selectivity or conjunctive coding has been suggested to help downstream brain regions to decode action-relevant stimuli. We show that the dHPC routes a strongly conjunctive code to the action-selection relevant basal ganglia (specifically, NAc).

Indeed, we find that conjunctive coding neurons improve the performance of a linear decoder tasked with identifying the reward zone. This raises the possibility that the dHPC routes enhanced conjunctive information to action-specific brain regions such as the NAc.

Overall, we show that dHPC routes an enhanced conjunctive code of space, speed, and lick information to NAc, and that this code can guide goal-directed appetitive behaviour such as licking.

I was fortunate to be joined in this work by @petra_moce and for the unwavering support from @SR_neurostar@twitter.com and @dzne @LIN_Magdeburg@twitter.com, and @IMPRSBrainBehav@twitter.com, as well as funding from @ERC_Research @dfg_public and #sfb_1089. Feel free to send comments and questions! 25/25

Also, if you're coming to NWG in Göttingen next week, please feel free to hit me up at poster ***T25-19A*** Wednesday 1-1:45pm (or write me to meet up).

A question for hippocampus experts. What are the best sources for data on primate hippocampal microcircuitry? I'm particularly interested in the variety, distribution and connectivity of local inhibitory interneurons.

(Note that I am looking for primate-specific data.)

#Neuroscience #Hippocampus

RT @obarnstedt
🚨🚨🚨PREPRINT ALERT🚨🚨🚨
We used dual-colour in vivo #two-photon #imaging and #optogenetics to learn what information the #brain’s dorsal #hippocampus sends to #NucleusAccumbens while mice navigated to a learned #reward site. What did we learn…? A🧵1/25 https://doi.org/10.1101/2023.03.09.531869

So... what are the differences between #ThetaSequences and #Replay (in the rodent #Hippocampus ?

Here is an illustration from real data!

Fig 1 shows ~70 #PlaceCells firing while a rat runs on a maze to reach a reward. See how the activity is different between running and pausing?
Fig 2 shows possible theta sequences.
Fig 3 shows possible replay.

Spot the differences & check alt text for more info!

PS: (very simple) #Matlab code to plot this is available here !

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