Calcium spikes know which way the wind blows!
Lily Nguyen and I wrote a dispatch on this fascinating work led by Itzel Ishida+@sethisachin.bsky.social+Gaby Maimon!
authors.elsevier.com/a/1mfk53QW8S...
On the left, the image shows a schematic of a fly head, ring neurons and EPG neurons together with some calcium imaging frames. On the right is a photo of a fly on a ball in virtual reality and another schematic of a VR system.
📢 Join us, the Haberkern lab, @uni-wuerzburg.de for a postdoc studying neural circuit mechanisms of navigation. You’ll spearheading neurophysiology experiments on our brand new 2P!
⏳ Apply by 28th February 2026
Details: www.haberkernlab.de/docs/ENPostd...
#neuroscience #academicjobs #postdoc
My paper on the head direction neurons in the larval zebrafish is now published on Nature! Read it here:
www.nature.com/articles/s41...
This work shows how neuromodulation of presynaptic terminals can enable associative plasticity at inhibitory synapses — a mechanism that may generalize well beyond navigation.
Huge congrats to all the authors — I’m incredibly proud of this study.
Preprint: www.biorxiv.org/content/10.6...
Illustration of plasticity strategy. EL neurons are depolarized using CsChrimson while EPG neurons are hyperpolarized using HcKCR1. Example data showing successful EL-induced EPG bump-cue plasticity despite EPG inhibition during induction.
This reveals a simple learning rule:
Coincident visual input + octopamine release is sufficient to induce plasticity at an inhibitory synapse.
A two-factor rule for unsupervised spatial learning.
fly under a 2-photon microscope
Is it sufficient?
Strikingly, pairing activation of octopamine neurons with a visual cue was enough to drive rapid plasticity — even when head-direction neurons were silenced during learning.
When we disrupted octopamine production in EL neurons, the head-direction network could no longer anchor to visual cues — even though the compass dynamics themselves remained intact.
Octopamine is necessary for the circuit to learn its visual surroundings.
Functionally, octopamine acts like a circuit-level retrograde signal:
it informs presynaptic visual terminals when head-direction neurons are active — without relying on a molecular retrograde transmitter.
EL neurons tile the ellipsoid body (grey). EM reconstruction of a single EL neuron (green). The most dense region of presynapses from the highlighted EL neuron are outlined in red while other colors indicate presynapse dense regions for the 17 other EL neurons. ER4d neurons receive inputs from every EL neuron around the ellipsoid body. EM reconstruction of a single ER4d neuron (purple) with input synapses from EL neurons in rainbow.
EL neurons receive input from head-direction cells and synapse directly onto nearby visual presynaptic terminals — right next to the inhibitory synapses that change with experience.
This forms a local feedback loop.
Each EL neuron (green) innervates a slice of the ellipsoid body, forming a feedback loop that relays activity from the EPG bump (red) to segments of visual ER axons (purple).
We discovered that a third neuron type provides the missing signal.
Neurons called EL neurons release the neuromodulator octopamine in a highly localized pattern that tracks the fly’s head direction.
In flies, we previously identified where this learning happens:
Visual neurons synapse onto head-direction neurons, and those synapses change with experience.
The catch?
These are inhibitory synapses — where classic Hebbian learning rules are poorly understood.
Head direction neurons act like an internal compass, combining self-motion w/ landmarks like visual cues.
Because environments change, these circuits must learn how sensory cues map onto internal direction.
Classic theories predict associative synaptic plasticity.
But the mechanism was unknown.
Schematic of how ER-EPG plasticity enables the bump of activity in EPGs to accurately track visual cues. As a fly makes a counter-clockwise turn (top to bottom) it will view visual cues (e.g. the sun) from a new angle and the EPG activity bump (red) will swing clockwise around the network by integrating self motion signals with these visual inputs. When the fly faces a different angle, distinct visual ER neurons are active. Plasticity forms a trough of weak synapses (large circles - strong synapses, small circles - weak synapses) that allow ER neurons with distinct visual tuning to move the EPG bump via disinhibition.
*First preprint from our lab* !!!!!
How does the brain learn to anchor its internal sense of direction to the outside world? 🧭
led by Mark Plitt @markplitt.bsky.social & Dan Turner-Evans, w/ Vivek Jayaraman:
“Octopamine instructs head direction plasticity” www.biorxiv.org/content/10.6...
Thread ⬇️
Our lab from @HHMINEWS & @UCBerkeley is looking for undergrads to come for an internship!
www.hhmi.org/programs/cec...
Congratulations! Super well deserved!
Come join our new Department of Neuroscience @ucberkeleyofficial.bsky.social as an Assistant Professor! aprecruit.berkeley.edu/JPF05041
A single neuron in fruit flies can trigger two different behaviors in response to the same odor.
www.cell.com/current-biol...
i wrote an essay for @thetransmitter.bsky.social about what it feels like to serve on an NIH grant review panel (study section) right now
www.thetransmitter.org/craft-and-ca...
Filipa Rijo-Ferreira named 2025 Freeman Hrabowski Scholar
Congrats to MCB's Filipa Rijo-Ferreira on being named a
@hhmi.org 2025 Freeman Hrabowski Scholar! 🎉👏
www.hhmi.org/programs/fre...
Big news this week for the Fisher lab!! It's a huge honor to join this community — and it's all thanks to the amazing scientists in my lab. We're extremely grateful for the support of our research!!
Thank you @marissascavuzzo.bsky.social 🤗
Honored join this community and extremely thankful for support of the exciting research being done by the amazing scientists in my lab!!
Horrible
Believe it a not, a third multisite connectomic project also lost funding. The multi-PI R01 led by @darbly.bsky.social with myself and @bassemh.bsky.social as co-PIs.
The IRACDA program was one of my favorites at NIGMS, good for the postdocs involved and for the institutions where they taught. Terminating it is just idiocy. Well said @ggnanadesikan.bsky.social
This is a super clear and helpful article explaining why the 15% indirect cost rate is unfair, hurts science, and does NOT increase $ for research:
www.science.org/doi/10.1126/...
Wow, major breakthrough in the development of broadly neutralizing bispecific antibody therapeutics against SARS-CoV-2, led by @stanford-chemh.bsky.social institute scholar @cobarnes27.bsky.social 😃
www.science.org/doi/10.1126/...
Today's the day! Minnesota, let's show up and make our voices heard to support science!
What a great event! Complete with shout out to @standupforscience.bsky.social
First, we are touring Nobel Prize Chemistry winner Professor Jennifer Doudna's lab to learn more about an NIH-funded CRISPR project and discuss how the NIH cuts will hurt groundbreaking research projects and lives.