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azvollan.bsky.social
Abraham Zelalem Vollan
@azvollan.bsky.social
220 followers 190 following 17 posts
PhD student in the Moser lab. Spatial cognition, grid cells, population dynamics, high-density ephys. MD from 🇳🇴
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azvollan.bsky.social
Abraham Zelalem Vollan @azvollan.bsky.social · Feb 4
Excited to share that our paper is now published in Nature! In this study, we uncovered a grid-cell-based circuit in medial entorhinal cortex that probes the surrounding environment with theta-paced, sweeping spatial representations 🧵
www.nature.com/articles/s41...
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Reposted by Abraham Zelalem Vollan
clykken.bsky.social
clykken.bsky.social @clykken.bsky.social · 14d
1/8
How can the brain create countless unique memories using a single, universal metric of space? We’ve been waiting for the answer to this for two decades!
Read it here:
www.biorxiv.org/content/10.1...
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azvollan.bsky.social
Abraham Zelalem Vollan @azvollan.bsky.social · 20d
Congrats, Thomas and team!!
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Reposted by Abraham Zelalem Vollan
rhythmicspikes.bsky.social
Abhilasha Joshi, PhD @rhythmicspikes.bsky.social · 21d
1/
🚨 New preprint! 🚨

Excited and proud (& a little nervous 😅) to share our latest work on the importance of #theta-timescale spiking during #locomotion in #learning. If you care about how organisms learn, buckle up. 🧵👇

📄 www.biorxiv.org/content/10.1...
💻 code + data 🔗 below 🤩

#neuroskyence
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azvollan.bsky.social
Abraham Zelalem Vollan @azvollan.bsky.social · Jul 12
Congrats to you all! Looks great in its final form🤩
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Reposted by Abraham Zelalem Vollan
matteoguardamagna.bsky.social
Matteo Guardamagna @matteoguardamagna.bsky.social · Jul 12
Our collaboration - from PhD work - examining input-specific (EC L3) contributions to rate and temporal coding in CA1 place cells is now out in @natcomms.nature.com 🔬🧠

rdcu.be/evWtz
Direct entorhinal control of CA1 temporal coding
Nature Communications - Temporal coding in the hippocampus is thought to be key for memory and predictions. Here, the authors show that blocking one entorhinal input affects two aspects of...
rdcu.be
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Reposted by Abraham Zelalem Vollan
aforli89.bsky.social
Angelo Forli @aforli89.bsky.social · Jul 9
Our study is out in Nature!
Using wireless Neuropixels we recorded hippocampal activity in freely flying bats and uncovered replay and theta(less) sweeps, revealing striking differences from classic rodent models.

👉 www.nature.com/articles/s41...
Replay and representation dynamics in the hippocampus of freely flying bats - Nature
Nature - Replay and representation dynamics in the hippocampus of freely flying bats
www.nature.com
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Reposted by Abraham Zelalem Vollan
rajatsxn.bsky.social
Rajat Saxena @rajatsxn.bsky.social · Jun 30
Our work with Maxim Bazhenov's group showing interleaved replay of new and old memories within individual Up states using a combination of biophysical modeling and electrophysiology experiments.
biorxiv-neursci.bsky.social
bioRxiv Neuroscience @biorxiv-neursci.bsky.social · Jun 30
Interleaved Replay of Novel and Familiar Memory Traces During Slow-Wave Sleep Prevents Catastrophic Forgetting https://www.biorxiv.org/content/10.1101/2025.06.25.661579v1
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Reposted by Abraham Zelalem Vollan
edvardmoser.bsky.social
Edvard I Moser @edvardmoser.bsky.social · Jun 26
Your brain doesn’t just passively track time ⏳ - it structures it.
In @Science.org we show that activity in 🧠 memory circuits (LEC) drifts constantly, but makes sharp jumps at key moments, segmenting life into meaningful events. (1/2)

👉 www.science.org/doi/10.1126/...
Event structure sculpts neural population dynamics in the lateral entorhinal cortex
Our experience of the world is a continuous stream of events that must be segmented and organized at multiple timescales. The neural mechanisms underlying this process remain unknown. In this work, we...
www.science.org
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Reposted by Abraham Zelalem Vollan
beneuroscience.bsky.social
Ben Kanter @beneuroscience.bsky.social · Jun 26
Our new paper out now in Science explores how neural activity in the lateral entorhinal cortex (LEC) *drifts* over time - and *jumps* at key boundaries - to help organize events in memory.

🔗 www.science.org/doi/10.1126/...

Here's a quick summary of what we found 🧵👇
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Reposted by Abraham Zelalem Vollan
nkrauth.bsky.social
Nathalie Krauth @nkrauth.bsky.social · May 28
Honored to share that our paper is out today in Nature Neuroscience:

www.nature.com/articles/s41...

We identify a hypothalamic-brainstem circuit linking internal states to locomotion: These projections drive safety-focused movement over competing behavior.

#Neuroscience #Hypothalamus #Locomotion
A hypothalamus–brainstem circuit governs the prioritization of safety over essential needs - Nature Neuroscience
Animals need to adapt behavior to balance survival with fulfillment of essential needs. Krauth et al. identify neurons in the lateral hypothalamus that, when activated, prioritize survival over other ...
www.nature.com
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Reposted by Abraham Zelalem Vollan
antofala.bsky.social
Antonio Falasconi @antofala.bsky.social · May 28
Forelimb movement control at the basal ganglia - brainstem interface!

Happy to finally share this work from me and @harsh-kanodia.bsky.social with Silvia Arber!

@biozentrum.unibas.ch @fmiscience.bsky.social

www.nature.com/articles/s41...
Dynamic basal ganglia output signals license and suppress forelimb movements - Nature
Basal ganglia output neurons fire dynamically in bidirectional and movement-specific patterns to license forelimb movements. 
www.nature.com
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Reposted by Abraham Zelalem Vollan
portugueslab.bsky.social
Portugues Lab @portugueslab.bsky.social · May 23
Are you interested in visual systems? How are they similar or different across species? Read the review by Ryosuke @ryosuketanaka.bsky.social and Ruben published today in @natrevneuro.nature.com. It is available here: rdcu.be/enlpC
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Reposted by Abraham Zelalem Vollan
beneuroscience.bsky.social
Ben Kanter @beneuroscience.bsky.social · Apr 26
As I transition over to Bluesky I have to plug our new #book. If you haven't already, check out the 2nd edition of The #Hippocampus Book!

academic.oup.com/book/59509?s...
The Hippocampus Book
Abstract. The Hippocampus Book investigates the structure, function and pathology of the hippocampus and related cortical areas. It highlights the importan
academic.oup.com
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Reposted by Abraham Zelalem Vollan
kasumbisa.bsky.social
Kadjita Asumbisa @kasumbisa.bsky.social · Apr 15
Excited to share the sequel to our 2022 paper! In this follow-up, we show that the stable head direction (HD) signals we reported in blind mice rely on stereo olfaction—that is, the comparison of odor info. between the two nostrils.

Link: www.nature.com/articles/s41...

🧵highlights below
Stereo olfaction underlies stable coding of head direction in blind mice - Nature Communications
Stereo olfaction involves comparing odor differences between the two nostrils. Here, using neuronal recordings and a behavioral test, the authors demonstrate that blind mice use stereo olfaction to fo...
www.nature.com
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azvollan.bsky.social
Abraham Zelalem Vollan @azvollan.bsky.social · Mar 31
Sorry for the delay, the dataset should be available now:)
Reposted by Abraham Zelalem Vollan
michaelreiser.bsky.social
Michael Reiser @michaelreiser.bsky.social · Mar 27
I know there's a 𝒍𝒐𝒕 going on right now, but I couldn’t be prouder to share this long-incubated labor of love: the complete connectome of the male 𝐷𝑟𝑜𝑠𝑜𝑝ℎ𝑖𝑙𝑎 optic lobe 🧠🪰
🔗 www.nature.com/articles/s41...
Connectome-driven neural inventory of a complete visual system - Nature
A connectome of the right optic lobe from a male fruitfly is presented together with an extensive collection of genetic drivers matched to a comprehensive neuron-type catalogue.
www.nature.com
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Reposted by Abraham Zelalem Vollan
antferrui.bsky.social
AntonioFR @antferrui.bsky.social · Mar 17
Excited to share our latest story! We found disentangled memory representations in the hippocampus that generalized across time and environments, despite the seemingly random drift and remapping of single cells. This code enabled the transfer of prior knowledge to solve new tasks
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Reposted by Abraham Zelalem Vollan
sarthakc.bsky.social
Sarthak Chandra @sarthakc.bsky.social · Feb 19
1/ Our paper appeared in @Nature today! www.nature.com/articles/s41... w/ Fiete Lab and @khonamikail.bsky.social .
Explains emergence of multiple grid cell modules, w/ excellent match to data! Novel mechanism for applying across vast systems from development to ecosystems. 🧵👇
Global modules robustly emerge from local interactions and smooth gradients - Nature
The principle of peak selection is described, by which local interactions and smooth gradients drive self-organization of discrete global modules.
www.nature.com
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Reposted by Abraham Zelalem Vollan
zilong-ji.bsky.social
Zilong Ji @zilong-ji.bsky.social · Feb 24
See here for our paper: www.cell.com/current-biol.... It is a great pleasure to work on this model with Tianhao, Si Wu and @neilburgess10.bsky.social. Also, I highly recommend to first read the experimental paper by @azvollan.bsky.social and colleagues: www.nature.com/articles/s41...
A systems model of alternating theta sweeps via firing rate adaptation
Ji, Chu et al. present a network model of direction and grid cells, which generates an internal direction signal comprised of alternating left-right sweeps of encoded location and direction, based on ...
www.cell.com
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Reposted by Abraham Zelalem Vollan
sunw37.bsky.social
Weinan Sun @sunw37.bsky.social · Feb 12
1/12 How do animals build an internal map? In our new paper, we tracked thousands of mouse CA1 neurons over days/weeks as they learned a VR navigation task. @nspruston.bsky.social & co-1st author @johanwinn.bsky.social
Video: www.youtube.com/watch?v=yw_4...
Paper: www.nature.com/articles/s41...
Learning produces an orthogonalized state machine in the hippocampus
YouTube video by Weinan Sun
www.youtube.com
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azvollan.bsky.social
Abraham Zelalem Vollan @azvollan.bsky.social · Feb 7
Amazing!🤩 Fascinating to see how completely different systems converge on left-right-alternation 🐜🐭🦇
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Reposted by Abraham Zelalem Vollan
carandinilab.net
Matteo Carandini @carandinilab.net · Feb 7
Neuropixels and Optogenetics are delighted to announce the birth of

Neuropixels Opto

Combining high-resolution electrophysiology and optogenetics

Today in bioRxiv

960 sites, 28 emitters, 2 colors

By Lakunina, @karolinazsocha.bsky.social, Ladd, et al

www.biorxiv.org/content/10.1...

(1/2)
A Neuropixels Opto probe with 3 blue emitters and 3 red emitters lighting up in succession, with corresponding neural activity in different layers of the cortex.
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azvollan.bsky.social
Abraham Zelalem Vollan @azvollan.bsky.social · Feb 4
Massive thanks to my supervisors @m-bmoser.bsky.social and @edvardmoser.bsky.social and coauthor @rjgardner.bsky.social for an incredible collaboration over many years! Thanks also to the technicians and lab members @kavlintnu.bsky.social and everyone else who contributed along the way (incl. 🐭!)
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azvollan.bsky.social
Abraham Zelalem Vollan @azvollan.bsky.social · Feb 4
Similar to how bats use directed sonar beams to sample information from the external environment, we believe that sweeps may sample from the brain’s internal model of the environment to facilitate encoding/retrieval processes.
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azvollan.bsky.social
Abraham Zelalem Vollan @azvollan.bsky.social · Feb 4
When presenting this work at conferences, people often point out the striking resemblance of left-right-alternating sweeps and directed echolocation clicks in bats (Yovel et al 2010)
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