Anatomically informed spatial smoothing

In this blog post, I want to describe the application and working principle of a few spatial smoothing algorithms that are implemented in LAYNII.

  1. Confined smoothing along similar anatomical structures with LN_GRADSMOOTH
  2. Smoothing along the layers with LN_LAYERSMOOTH
  3. Smoothing within columns with LN_LAYERSMOOTH
  4. Smoothing across specific spatial dimensions only with LN_DIRECT_SMOOTH
  5. Smoothing long the time domain with LN_TEMPSMOOTH

Continue reading “Anatomically informed spatial smoothing”

3D-printing nii data

In this blog post, I want to write about pipelines on how to prepare Nifti-brain data and make them printable by a 3D-printer.

Two pipelines are shown. One pipeline describes the 3D-printing the cortical folding structure that is estimated with Freesurfer and subsequently corrected with Meshlab. And another pipeline describes how you can 3D-print any binary nii-volume by using the AFNI-program IsoSurface and correct the output with netfabb.  Continue reading “3D-printing nii data”

How to convert any paper figure into a layer-profile

Often we would like to normalize depth-dependent fMRI signals and assign it to specific cytoarchitectonially defined cortical layers. However, we often only have access to cytoarchitectonial histology data in the form to figures in papers. But since we only have the web-view or the PDF available, we cannot easily extract those data as a layer-profile. Since most layering tools are designed for nii data only, paper figures (e.g. jpg or GNP) are not straight-forwardly transformed to layer profiles.

In this blob post, I describe a set of steps on how to convert any paper figure into a nii-file that allows the extraction of layer profiles.

Continue reading “How to convert any paper figure into a layer-profile”

Unwanted spatial blurring during resampling

In layer-fMRI, we spend so much time and effort to achieve high spatial resolutions and small voxel sizes during the acquisition. However, during the evaluation pipeline much of this spatial resolution can be lost during multiple resampling steps.

In this post, I want to discuss sources of signal blurring during spatial resampling steps and potential strategies to account for them.

Continue reading “Unwanted spatial blurring during resampling”

Smoothing within layers

Smoothing within layers can be advantageous for multiple reasons:

  • Increasing the CNR without loosing spatial information across cortical depths.
  • Visualization of striping pattern across columnar structures.
  • Avoiding leakage of physiological noise from CSF space into GM tissue.

image88.gif Continue reading “Smoothing within layers”