Questions about unit conversion (ADC vs µV) in SpikeInterface + Kilosort4 pipeline

[wenxin8023]

Hi,

I am working with extracellular recordings acquired using Intan and flexible electrodes. My current data processing pipeline is:

1. Load raw .rhd data recorded with Intan
2. Preprocess the data using SpikeInterface
3. Save to binary format
4. Run spike sorting with Kilosort4
5. Use SpikeInterface quality metrics for initial labeling
6. Manually curate and correct units in Phy
7. Extract template waveforms using SpikeInterface

After loading the raw Intan data, is it sufficient to apply unsigned_to_signed() Handle unsigned data types to convert the data to signed integers? Do I need to apply both unsigned_to_signed() and scale_to_uV() Work with physical units in SpikeInterface recordings , or is using unsigned_to_signed() alone sufficient before preprocessing and spike sorting?

If I don’t convert the data to microvolts (µV) during preprocessing and keep everything in raw ADC units, will this affect:

• Kilosort4 spike sorting results?
• SpikeInterface quality metrics?
• Template computation?
• Any downstream analyses?

My understanding is that most spike sorters (including Kilosort) operate on raw ADC units, but I would appreciate clarification on best practices in this case.