Runita Shirdhankar

@runitas.bsky.social

PhD candidate @mpinb.mpg.de‬ | Interested in understanding Navigation in the Subterranean World of Rodents

Happy to say our head-direction-cell-in-3D is finally out! doi.org/10.1038/s420... Confirms that the brain's compass uses a dual-axis rule (like an iphone does) to maintain a constant estimate of horizontal heading even when the head is not horizontal. Blogpost explanation here: shorturl.at/9VdGM

How the brain adapts its 2D compass for a 3D world

The brain’s neural compass seems 2D, detecting only left and right head-turns. However, if the head is tilted in 3D, its rotation around the vertical axis also covertly changes its horizontal facing ...

communities.springernature.com

New paper from Ulanovsky's group: With brain recordings from🦇 flying in a 200m tunnel, the group discovered that place cells of CA1 exhibit dense spatial coding, i.e., multiple place fields, and cells of CA3 exhibit ultrasparse coding, i.e., one place field. www.nature.com/articles/s41...

Sparse-to-dense coding transformation between hippocampal areas CA3 and CA1 - Nature

The hippocampus exhibits a CA3-to-CA1 coding transformation that combines fast learning with an efficient, compressed neural code.

nature.com

Our second ICARUS system is in space 🚀🛰️ At 9am PT, a Falcon 9 rocket left Earth from California, taking an ICARUS payload with it. This is the beginning of ICARUS 2.0—independent, robust, real-time—with more ICARUS satellites to come. Read more▶️https://tinyurl.com/mw48c398 📸 Space X, EnduroSat

Credit: Space XCredit EnduroSat

Job alert! We are seeking a rodent in vivo electrophysiologist to work on coordination between anterior thalamus and hippocampus in rats using Neuropixels. Beautiful Scotland, leading university (Glasgow) and vibrant intellectual setting. Post is 23 months but hopefully extensible. Details here 👇

“I shall send off the manuscript today or Monday. It is an extremely poor affair; I must say something & have nothing worth saying. Lock it up carefully, I hate it to that extent it would break my heart to write it again.” Charles Darwin captures the joy of academia in a letter to his daughter, 1871

The hippocampal map has its own attentional control signal! Our new study reveals that theta #sweeps can be instantly biased towards behaviourally relevant locations. See 📹 in post 4/6 and preprint here 👉 www.biorxiv.org/content/10.6... 🧵(1/6)

Attention-like regulation of theta sweeps in the brain's spatial navigation circuit

Spatial attention supports navigation by prioritizing information from selected locations. A candidate neural mechanism is provided by theta-paced sweeps in grid- and place-cell population activity, which sample nearby space in a left-right-alternating pattern coordinated by parasubicular direction signals. During exploration, this alternation promotes uniform spatial coverage, but whether sweeps can be flexibly tuned to locations of particular interest remains unclear. Using large-scale Neuropixels recordings in freely-behaving rats, we show that sweeps and direction signals are rapidly and dynamically modulated: they track moving targets during pursuit, precede orienting responses during immobility, and reverse during backward locomotion — without prior spatial learning. Similar modulation occurs during REM sleep. Canonical head-direction signals remain head-aligned. These findings identify sweeps as a flexible, attention-like mechanism for selectively sampling allocentric cognitive maps. ### Competing Interest Statement The authors have declared no competing interest. European Research Council, Synergy Grant 951319 (EIM) The Research Council of Norway, Centre of Neural Computation 223262 (EIM, MBM), Centre for Algorithms in the Cortex 332640 (EIM, MBM), National Infrastructure grant (NORBRAIN, 295721 and 350201) The Kavli Foundation, https://ror.org/00kztt736 Ministry of Science and Education, Norway (EIM, MBM) Faculty of Medicine and Health Sciences; NTNU, Norway (AZV)

biorxiv.org

New paper out in Mammalian Biology: Walking backwards, as impractical as it may seem, is mastered by the Ansell's mole-rat (Fukomys anselli). In this study, we showed that mole-rats can walk backwards and forwards with equal ease. This is likely an adaptation to their subterranean habitat.