Details on human developmental reference atlas - sectioning intervals

I had a technical question regarding the developing human reference atlas.
In the 21 pcw atlas, I wanted to calculate the distance between sections (Nissl/Atlas). From the supplementary information, I could see that sections were 50 microns thick but there were variable intervals between sections depending on slab location. I couldn’t see where those intervals changed along the A-P axis. I am trying to make an estimate of structures that run btwn sections 10 to 40s.
Thanks in advance for people’s thoughts!

Hello Mercedes and thank you for patiently awaiting our response.

Below is a spreadsheet that indicates all reference atlas plate sections per slabs derived from whole brain (there were 4). Each number indicates the physical order of sections chosen for atlasing among all others taken in sequence. For example, the first reference atlas drawing was done on the 26th section of slab 1. That means [26x20um] deep. The next section is 77, which is [(77-26)x20um] away. This understanding should allow one to answer most sampling questions except slab-to-slab transitions, which could not be accurately calculated for multitude of mechanical processing reasons (and thus not included here). Suffice it to say however that the gap between slabs was kept to an absolute minimum, as demonstrated in the relative continuity of structures across them.

Let us know if you have further questions.

Stay safe and well.


Hi Josh,

This is very helpful! I will guestimate then btwn slabs but the sequential organization gives a great sense of distances.
Thank you for organizing the section info so clearly! This atlas has been such an incredible resource.

Be well and appreciate your time.