Sure, but the std cartoon assumes a simple relationship of neurons driving a host of mechanisms w/ a single vascular response per voxel, which most reduce to a (single) canonical HRF. This at least invokes two components. And it offers a testable hypothesis in humans.
CBV & CBF mismatch: exactly. But where, and why? I've always assumed the CBV was slower to come back than CBF for the same responders, but if it's two different populations of neurons and only one causes functional hyperemia, that would cause a mismatch. It's a guess, trying to relate to fMRI.
I’m wondering if the Arousal+ neurons might trigger a large change in CBF whereas the Arousal- neurons don’t. This might then explain the post-stim undershoot, which earlier studies showed could be persistent changes in CBV. Thoughts @northernthrux.bsky.social @danielhandwerker.bsky.social ?
The supply of blood to brain tissue is thought to depend on the overall neural activity in that tissue, and this dependence is thought to differ across brain regions and across brain states. However, studies supporting these views have measured neural activity as a bulk quantity and related it to blood supply following disparate events in different regions. Here we measure fluctuations in neuronal activity and blood volume across the mouse brain, and find that their relationship is consistent across brain states and brain regions but differs in two opposing brainwide neural populations. Functional ultrasound imaging (fUSI) revealed that whisking, a marker of arousal, is associated with brainwide fluctuations in blood volume. Simultaneous fUSI and Neuropixels recordings showed that neurons that increase activity with whisking have distinct haemodynamic response functions compared with those that decrease activity. Their summed contributions predicted blood volume across states.Brainwide Neuropixels recordings revealed that these opposing populations coexist in the entire brain. Their differing contributions to blood volume largely explain the apparent differences in blood volume fluctuations across regions. The mouse brain thus contains two neural populations with opposite relations to brain state and distinct relationships to blood supply, which together account for brainwide fluctuations in blood volume.
How does blood flow relate to brain activity? We discovered that it reflects two neural populations affected oppositely by arousal. Together, they explain neurovascular coupling in all brain regions and brain states!
Out today in Nature: rdcu.be/fdC2A
@uclbrainscience.bsky.social
📣 Job alert: We are recruiting a Prof in Neuroscience with MRI expertise to join us at @unirdg-cinn.bsky.social and @unirdg-psych.bsky.social. See tinyurl.com/2kdjph8v for details. Contact me for info/chat. Please spread the word
#neuroskyence #neurojobs
tedana, multi-echo fMRI denoising software, newsletter includes tedana v26.0.3 updates and details of multi-echo fMRI ed course at OHBM 2026. groups.google.com/g/tedana-new...
Tau-induced mitochondrial reverse electron transport drives neurodegeneration www.biorxiv.org/content/10.64898/2026.04...
WTI crude. Going up like Artemis II since April Fool’s Day.
Right so that would be a hard no from the markets, Mr Trump. Care to revise your so-called plans?
Every accusation is an admission. This is what feeble men with big egos crying for help looks like. It would be sad and pathetic if it wasn’t so bloody serious.
How do we define "good" fMRI data? Especially with resting state, there are circularity risks if we evaluate data quality as showing the networks we expect to see. Javier Gonzalez-Castillo (& me & others) developed pBOLD, a new metric that uses multi-echo info. www.biorxiv.org/content/10.6... 1/8
Do you censor high motion frames in fMRI? In two preprints by @twktan.bsky.social @mandymejia.bsky.social, we find that we may be censoring too much!
doi.org/10.64898/202...
arxiv.org/html/2603.07...
Strict censoring leads to worse personalized TMS targets than no censoring, even with high motion!
Super proud of @sjoerdmeijer.bsky.social who demonstrated that amygdala-TUS slows initial threat acquisition and enhances subsequent extinction. Great collaboration with @lennartverhagen.bsky.social and @deVoogdld.bsky.social ea. Thanks to @ERC.europa.eu.
www.science.org/doi/10.1126/...
Cell-Type-Specific Bidirectional Modulation of the Cortico-Thalamo-Cortical Sensory Pathway by Transcranial Focused Ultrasound (tFUS) www.biorxiv.org/content/10.64898/2026.03...
A new fMRI quality metric using multi-echo information: Theory, validation and implications www.biorxiv.org/content/10.64898/2026.03...
Simultaneous measurement of water transport across the blood-brain and blood-CSF barrier in the human brain with arterial spin labeling MRI
pubmed.ncbi.nlm.nih.gov/41846267/
Sleep alters neurovascular and hydrodynamic coupling in the human brain
pubmed.ncbi.nlm.nih.gov/41849399/
The fringe field of a 3 T magnet is circa 3 T/m at the bore, a Bruker Biospec 7 T is 10 T/m at the bore! The bigger gradient the better!
I got a provisional patent on FIEFUS in Oct 25 but have no ability to work on it myself. LMK if you do!
Lower freqs (200-350 kHz) for larger displacements in the gradient direction (microns to tens of microns) and less focal transducers (cm foci) would both enhance the circulating E field according to Faraday's law. The dt is probably limited by the brain mechanical properties, but fast is best!
And on the issue of TFUS combined with other methods for localized electric field effects, if anyone is interested in TFUS in the presence of a strong static magnetic field, please make contact. Faraday induction-enhanced FUS (FIEFUS) would be weak but it might work!
Now published:
pubmed.ncbi.nlm.nih.gov/41807379/
A harbor seal opens its mouth wide just above the water’s surface.
By mapping the brains of seals and sea lions, researchers have uncovered specialized neural circuits that have evolved to support the control of complex vocal behavior and learning in the species.
Learn more this week in Science: https://scim.ag/4bpsJYU
Diversity of tasks>>resting state for predictive power.
Multi-task fMRI outperforms resting-state fMRI for revealing task-invariant organization of the human brain www.biorxiv.org/content/10.64898/2026.03...
A step toward non-invasive electrophysiology: our @commseng.nature.com paper demonstrates acoustoelectric neural recording in mice using ultrasound-induced frequency mixing, with controls to rule out artefacts. rdcu.be/e4GSw #ultrasound #neurotech
New paper just out 🎉 In vivo acoustoelectric neural recording: focused ultrasound + frequency mixing lets us shift & demodulate neural signals from the ultrasound focus. rdcu.be/e4GSw
True. We also have a balkanized user base over three scanners and there's no meaningful overlap so everyone only looks out for their own interests. Oh well, something for future directors and managers to worry about and fix if they want!
Ah, the vision is the bit we seem to be missing. It’s organic, bottom up here, which has pros and cons!
Would you be up for a directorship back in the USA for, say, 5 years, or are you done with directing like I’m done with managing? Asking for a friend…
