Discussion: meetings/2025-12-09

[ryan-gillis]

Hi all,
I am one of the operators for the Neuropixels experiments and upon reviewing the meeting and the analyses presented during the meeting, I noticed that the channels used for the LFP analysis were labeled 0-100, and were discussed as if they were in cortical layers. For our probes, 0 has always been the channel nearest to the tip of the probe, and so higher channel numbers would be more superficial. All probes are inserted to a depth of 3000 microns from the surface, and the surface determination is usually accurate within ~200 microns, so on our end we would expect channels 280-320 to be nearest to the surface of the brain. I am unsure if the analysis code transforms the channel numbers anywhere, so I just wanted everyone to be cautious of the channel numbers when analyzing the data. You should be able to see a clear difference in activity between channels that were in the brain and outside of the brain, so it may be most useful to plot these analyses with all channels to confirm that further analyses are on the correct part of the probe.