double-sided probes

[WeissShahaf]

Dear Devs,

what is the best way to handle double-sided probes?
should i treat the two sides as different probe groups or if they are thin enough as a 3d probe with contacts having same x,y, but different z?

[samuelgarcia]

It is a complicated case that was not taken in account.
One way could be to handle then using 3d probe and playing on the plane of the contact a small z diff would be also a good idea. Maybe you could also treat then as 2 shanks...
@alejoe91 lets have a discussion about this

[alejoe91]

Hi @WeissShahaf

@samuelgarcia yeah I was also thinking this could be handled by 3d probes. In addition, probe contours could also handle 3d point to describe a 3D polygon. I think that the 2 sides could also be split in two shanks, since you would not expect to see the same units and one would probably want to spike sort each side separately.

@WeissShahaf do you have a referebce for the probe you're using?

[WeissShahaf]

@alejoe91 the new 128ch cambridge probes (will soon be updated) have a thickness of 30um.
at that thickness, you can very well detect the same cells on both sides.

for example the H7. is 15 um thick, the double-sided version is 30 um thick. same layout:

<style> </style>

part	electrodes_n	shank_lenght_mm	shanks_n	shank_thickness_um	electrodes_total	electrodesPerShank_n	electrodesCustomPosition	ElectrodeShape	electrodeWidth_um	electrodeHeight_um	electrodeImpLow_kOhm	ElectrodeImpHigh_kOhm	OptoSafe	shankBaseWidth_um	shankTipWidth_um	probeShape	electrode_yShiftCol	electrode_distrib_shape	electrode_cols_n	electrode_rows_n	shankSpacing_um	electrodeSpacingWidth_um	electrodeSpacingHeight_um	electrodeSpanWidth_um	electrodeSpanHeight_um
H7	64	9	2	15	64	32	-20.0 25.0 -20.5 75.0 -21.0 125.0 -21.5 175.0 -22.0 225.0 -22.5 275.0 -23.0 325.0 -23.5 375.0 -24.0 425.0 -24.5 475.0 -25.0 525.0 -25.5 575.0 -26.0 625.0 -26.5 675.0 -27.0 725.0 -27.5 775.0 0.0 0.0 0.5 50.0 1.0 100.0 1.5 150.0 2.0 200.0 2.5 250.0 3.0 300.0 3.5 350.0 4.0 400.0 4.5 450.0 5.0 500.0 5.5 550.0 6.0 600.0 6.5 650.0 7.0 700.0 7.5 750.0	rect	11	15	50	50	TRUE	60	60	-40.0 825.0 -30.0 0.0 -10.0 -65.0 7.0 0.0 25.0 825.0	0 -25	Vshaped	2	16	250	52	50	63 33	775

so i was thinking just duplicating the electrode positions, adding a -15 to the z of the first 64 channels, and a +15 to the last 64 channels

[WeissShahaf]

the DBC JANUS probes like the P64-1 are also 30um.
i'm not sure about Neuronexus Fusion probes that will soon come are in testing now.
so my intuition is to go as 3D probes. and maybe sort by group. But I'm not sure how the different sorters deal with shanks (total seperation or still applying the radius criterion for detected spikes?)
and i'm pretty sure none deal with 3D. so maybe representing as different shanks is the better option until they do?