Denis Chaimow

Vascular draining confounds laminar decoding in fMRI https://www.biorxiv.org/content/10.1101/2025.08.26.672278v1

What started as a journal club on layer decoding turned into a project thanks to @karolisdegutis.bsky.social. Our preprint challenges a widespread assumption in the field: MVPA is not immune to vascular confounds in laminar GE-BOLD decoding, as shown using a mechanistic laminar response model.

Happy to see this out: our new preprint shows that laminar GE-BOLD fMRI decoding isn’t immune to vascular draining biases. Simulations reveal false positives due to multivariate signal spread across layers, but oversampling + deconvolution can (sometimes) improve specificity.

Spatial specificity of the functional gradient echo and spin echo BOLD signal across cortical depth at 7 T Functional magnetic resonance imaging (fMRI) at high magnetic field strengths (≥ 7 T) is a promising technique to study the functioning of the human brain at the spatial scale of cortical columns and ...

I’m happy to share that our manuscript on the cortical depth-dependency of the GE- and SE-BOLD point spread function at 7 Tesla is now available on bioRxiv!

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

Neural dynamics of visual working memory representation during sensory distraction Dynamic shifts in neural coding combined with stable population subspaces enable visual areas to concurrently represent sensory inputs and working memory without mutual interference.

Very happy to share our work on the neural dynamics of visual working memory maintenance during sensory distraction; now out as a VOR on eLIife: elifesciences.org/articles/99290

New paper in Imaging Neuroscience by Fakhereh Movahedian Attar, Nikolaus Weiskopf, et al:

Short association fibres form topographic sheets in the human V1–V2 processing stream

doi.org/10.1162/imag...

I’d like to thank everyone involved in the project! @romy-lorenz.bsky.social, @karolisdegutis.bsky.social, Daniel Haenelt, Robert Trampel, @nikweiskopf.bsky.social

We argue that our results are biologically plausible, considering both previous research and methodological aspects of layer fMRI acquisition and analysis. Consequently, the functional role of human dlPFC layers, especially deep layers, in working memory remains uncertain.

Using confidence interval estimation and a series of control analyses, we show that the failure to replicate was likely not an issue of low sensitivity, data quality or methodological choices, such as automatic segmentation and ROI selection.

We replicated the superficial layer involvement in working memory manipulation but found no evidence for deep layer-specific activation during motor response. Instead, we observed activation across both layers.

We used a fully automated, pre-registered analysis pipeline, that included automatic ROI definition by combining anatomical information (HCP MMP 1.0 atlas) with functional activation.

Layer-dependent activity in human prefrontal cortex during working memory - Nature Neuroscience By developing layer-specific functional MRI techniques for a high-order cognitive brain area, Finn et al. dissociate activity in superficial and deeper cortical layers during different periods of a wo...

A seminal layer fMRI study (Finn et al. 2019) demonstrated that dlPFC layers were active during the manipulation of working memory items, whereas deeper layers were more engaged during motor responses.
www.nature.com/articles/s41...
@esfinn.bsky.social

Challenges in replicating layer-specificity of working memory processes in human dlPFC Although working memory reliably activates the dorsolateral prefrontal cortex (dlPFC), the functional significance of its distinct cytoarchitectonic layers is not well understood in humans. A recent f...

Excited to share our latest preprint: "Challenges in replicating layer-specificity of working memory processes in the human prefrontal cortex.”, where we attempted to replicate layer-specific fMRI findings in the human dlPFC during a working memory task.
www.biorxiv.org/content/10.1...

I’d like to thank everyone involved in the project! @romy-lorenz.bsky.social, @karolisdegutis.bsky.social, Daniel Haenelt, Robert Trampel and @nikweiskopf.bsky.social

We argue that our results are biologically plausible, considering both previous research and methodological aspects of layer fMRI acquisition and analysis. Consequently, the functional role of human dlPFC layers, especially deep layers, in working memory remains uncertain.

Using confidence interval estimation and a series of control analyses, we show that the failure to replicate was likely not an issue of low sensitivity, data quality or methodological choices, such as automatic segmentation and ROI selection.

We replicated the superficial layer involvement in working memory manipulation but found no evidence for deep layer-specific activation during motor response. Instead, we observed activation across both layers.

Challenges in replicating layer-specificity of working memory processes in human dlPFC https://www.biorxiv.org/content/10.1101/2025.01.31.635930v1