Hercules1 vs hercules2 vs 'hercules3'

could someone point me to documentation that explains the difference between editing target choices Hercules1 and Hercules2? In the GUI, ‘Hercules3’ is also an option, but I wasn’t sure whether that was a bug
thank you!

Hi Sam,

I hope I identified the right person by their initials :wink: and thank you for reaching out.

The GUI jobFile generator was a community contribution and is currently not reflecting the most recent definitions of the editing targets. I will add this to the list of bugs to be fixed in a future update.

If you want to analyze HERCULES data as defined in (Advanced Hadamard-encoded editing of seven low-concentration brain metabolites: Principles of HERCULES - PubMed) you have to pick the seqType = HERCULES and the editingTarget = {‘GABA’,‘GSH’}. I have attached one of my HERCULES jobFiles for reference.

Let me know if you get stuck during the analysis.


jobSiemensHERCULES.txt (8.7 KB)

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thank you Helge! one question about the job file you attached

(1) the fitting style was set to separate rather than concatenated. My impression from the paper you attached was that the simultaneous fitting was the ‘best’ for most of the metabolites based on the CV table and therefore was better than fitting the 3 separately - is there a reason that you would recommend setting the fit style to ‘separate’? If so, I would be curious to hear how to consolidate the information from the 3 separate quantify tables that are produced from the separate fits (eg which quantity table should I use for each metabolite??)

Hi Sam,

Sorry for the delayed answer. The problem with the current implementation of the concatenated fit in Osprey is that it is not delivering robust results. If you look at the model results from the concatenated setting you will see some unreasonable fits. Therefore, we are currently recommending using the separate fit which means that you are losing some of the advantages of HERCULES and end up performing a slightly modified HERMES experiment.

The good news is that we are working on the multi-spectra fitting now.

About which concentration to pick from which table. I’d recommend the following:

sum: tCr, tCho, INs, Glx, Glu, Gln, NAA, tNAA
diff1: GABA and GABA+
diff2: Asc, Asp, Lac, GSH, NAAG, PE

Hope this answers some of your questions.