What is Probe.contact_side_numbering?

[rly]

The Probe neurodata type defined in this extension has a required boolean attribute contact_side_numbering. The docstring simply says "is contact_side_numbering enabled"... The Spyglass docstring says "Facing you when numbering". This still confuses me. What exactly does contact_side_numbering mean? Does it mean the "first" contact is at the tip of the probe, where first means it is the first channel in the returned data? Is this a useful attribute to store with the Probe (can it be optional)? @edeno @samuelbray32

Just trying to make this work for Berke Lab data and probes, with implications for how other groups use the Probe extension to get their data into Spyglass. cc @calderast

[samuelbray32]

I'll check with members in our lab to see if anyone uses this information, and if so how do they define it. First glance suggests that it isn't used in any packaged spyglass pipelines.

[samuelbray32]

Sorry for delay. Answer from the lab group:

contact_side_numbering is true if the electrodes were numbered in a scheme wherein the contacts were electrodes facing up toward the viewer and false if the numbering was based on the electrodes facing down. This is relevant when the goal is to determine where in the tissue each electrode contact is located.

I think it could be optional, as some devices like tetrodes don't have any real meaning more this

[rly]

Thank you @samuelbray32 . Unfortunately I am still a little confused. How does contact_side_numbering == True vs False change the interpretation of where in the tissue each contact is located?

If I am looking at a probe, e.g., this high-density, multi-shank polymer probe from Chung et al., 2018:

The contacts have ids and coordinates relative to the probe. I get that the contacts are on one side of the probe. Is it that, for example, the contact with id 1 is always on the left-most shank, regardless of whether you are looking at the probe with the contacts facing up toward the viewer vs facing down? And therefore contact_side_numbering tells you whether the probe was flipped? But then how do you know which way the probe was inserted into the brain? Maybe I am missing something...

I think this would be useful to document in the extension and in Spyglass.

In any case, I will make the field optional in the extension.