Jan M. Ache

the beatles are walking across a zebra crossing on a city street . ALT: the beatles are walking across a zebra crossing on a city street .

We thank @dfg.de and the #NeuroNex program for generously funding our work, and our neighbours and colleagues at @uni-wuerzburg.de, especially the Department of Neurobiology and Genetics (Charlotte Förster, Chris Wegener, and @silkesachse.bsky.social).
Stay tuned - more walking papers on the way...

This study was a team effort, with some surprises and directional changes on the way. I am grateful to the entire crew, especially Stefan & Sander, Fathima, Feffo, Mert, and Aleyna from my lab, Adrián and @postpop.bsky.social from the Clemens Lab, and Axel and Ansgar from the Büschges lab.

Both MDN and DopaMeander are gated out (switched off) during flight. Showing that behavioral state-dependent gating occurs simultaneously across levels of motor control and is bidirectional in nature, allowing the specific boosting of motor control modules in the appropriate behavioral context.

Finally, we leveraged the fact that we identified neurons controlling walking across hierarchical levels to ask how the brain ensures that appropriate motor output is generated in different behavioral states. To do so, we recorded MDN and DopaMeander in flies transitioning into and out of flight.

DopaMeander, in contrast, contributes to forward walking, but its activity is particularly linked to turning in the ipsiversive direction - so that the right DopaMeander contributes to rightward turns, and the left DopaMeander to leftward turns...

We quantified this by building linear-nonlinear models which estimate how, precisely, each neuron controls walking parameters. It turns out MDN does not simply ‘switch’ the walking direction but encodes a backward walking drive that increases from forward walking, to stopping, to backward walking.

We then performed patch-clamp recordings from DopaMeander and MDN in spontaneously walking flies. DopaMeander is more active during forward walking, whereas MDN is more active during backward walking – as predicted from the phenotypes of both neurons. Hence, they control opposite walking regimes.

Locomotor and olfactory responses in dopamine neurons of the Drosophila superior-lateral brain Marquis and Wilson describe the physiology of three types of dopamine neurons in the Drosophila brain. They show that all these neurons are correlated with the fly’s walking speed, and some also respo...

Why get excited about this? Dopamine is tightly linked to motor control in the vertebrate nervous system. In flies, dopamine is strongly linked to learning and memory and decision-making processes, but less so to motor control or walking (one great exception here: tinyurl.com/3xx88j37).

Activation, silencing and stochastic labeling experiments reveal that DopaMeander drives forward walking and turning. It is also required for fast walking - flies with silenced DopaMeander walk and turn much less when facing an optomotor stimulus, which induces walking in circles in controls.

Here, we identified a novel, dopaminergic cell type in the brain which drives forward walking – DopaMeander. Connectome analyses reveal DopaMeander modulates a circuit in a specific brain region (the AVLP), which integrates mechanosensory cues from the legs, and includes walking-related neurons.

a man in a suit and hat is walking down a hallway carrying a briefcase ALT: a man in a suit and hat is walking down a hallway carrying a briefcase

Next, we turned our attention to forward walking – the preferred way for flies to get around in the world (some argue ‘flies’ should really be called ‘walks’). Forward walking is more versatile and accordingly controlled by larger populations of neurons across complex sensorimotor hierarchies.

We demonstrate that this switch in walking direction is driven by Moonwalker Descending Neurons (MDNs) – which were originally discovered by @salilbidaye.bsky.social. Our patch-clamp recordings show MDNs encode antennal touch. MDNs are also required for antenna-driven backward walking.

First, we looked at backward walking, which typically occurs in response to a threat – or when animals bump into an object or a conspecific. To simulate the sensory stimulus of bumping into something, we poked the antennae of forward walking flies – and found that they reverse walking direction.

a baby wearing a black space racer shirt ALT: a baby wearing a black space racer shirt

Preprint Alert! Walking mostly feels natural and easy to us - but the neuronal control of walking is actually incredibly complex. We leveraged the fruit fly as a genetically tractable animal model with a compact nervous system to ask how the brain controls walking direction: tinyurl.com/flywalk. 🧵..

This isn't a coincidence, IMO. The fly community is generally super rigorous - because there are so many tools and techniques available, people expect you to really nail things in order to get published (and keep getting funded)

We're hiring! Two exciting opportunities in our Lab @unibirmingham.bsky.social

Come work with us on decision-making and neural circuits in Drosophila. Please share!

Senior Research Technician + Postdoctoral Research Fellow

Deadline: 10 July

More info here: www.rezavallab.org

Very happy to share that the awesome @merterginkaya.bsky.social was awarded a @dfg.de #WalterBenjamin scholarship for his postdoc project on mechanisms for action-selection in visual sensorimotor pathways. The more Mert the better. 🎉

It’s a wrap for the 2025 Crete Fly Circuits meeting! Huge thanks to our friends at the OAC for hosting us, our fantastic speakers for sharing their latest and greatest unpublished works, and to Eugenia, Marion, Nilay, and Richard for the fun we had organizing this. See you all in 2027!

A Role for Exaptation in Sculpting Sexually Dimorphic Brains from Shared Neural Lineages Sex differences in behaviours arise from variations in female and male nervous systems, yet the cellular and molecular bases of these differences remain poorly defined. Here, we take an unbiased, sing...

New preprint from lab: www.biorxiv.org/content/10.1... Sexual dimorphism arises not through wholesale transcriptional reprogramming, but via selective sex-specific survival of neurons defined by birth order and shared developmental programs.

The sky knows what’s up. Happy #pridemonth! 🌈

Very happy that we were able to contribute a few recordings from our favorite #insulin producing cells to this great story from @buelowlab.bsky.social!

Hey spinal/ventral nerve cord folks. we’re organizing this cross species “cords” meeting @hhmijanelia.bsky.social . Hurry up and upload your abstracts. As a trainee these were my favorite meetings (small and focused) where I got the most useful feedback. DM in case of any Qs.

#CharlotteFörster #Farewell #Symposium #Chronobiology #GermanClockClub2025 #CircadianClock #Drosophila #Fruitfly #Würzburg #KatharinaBeer #RudolfoCosta #BambosKyriacou #OrieSchäfer #MonikaStengl #SheebaVasu #TaishiYoshii #CharlotteHelfrichFörster #Circadia_Clock @uni-wuerzburg.de

Excited to share my PhD paper is out! We studied how motion vision is processed beyond the optic lobes to help flies walk straight. It has been a wonderful collaboration with @michaelreiser.bsky.social, @dddavi.bsky.social and many others not in bluesky!
Paper + digest here: bsky.app/profile/cham...

Ritu published two fantastic papers in @elife.bsky.social and defied a pandemic on the way - with a smile on her face, a keen mind, and an incredible drive to move all obstacles out of her way. She will keep investigating the insulin system - but will switch to 🐁. Stay tuned for her next big moves!

I could not be more proud to present the the first PhD graduate from my lab - @ritujabisen.bsky.social! Rituja basically walked into an empty lab in the beginning of 2020, helped build the lab’s first ephys rig from scratch, and then patched her heart out over the following years…

Yay - the extensive review Ansgar Büschges and I wrote on insect motor control and the many things insects can teach us about our own nervous systems just came out in Physiological Reviews @apsphysiology.bsky.social. Check it out - it's free: journals.physiology.org/doi/epdf/10....

the Dunkin’ logo has never felt more accurate

Join us for a fully funded, 4-year PhD, a collaboration between Northumbria, Durham and Mainz Universities to study the evolution of the neuronal basis of defence behaviours in Drosophila!

Application and full PhD advert:
www.findaphd.com/phds/project...

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.

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...