Split EEG sensors left/right when doing sensor-space expression plots

[caiw]

Currently EEG sensors are assigned to both hemispheres: we aren't using any positional information to assign them.

Note to the person who looks at this issue next

I have a memory that there was a reason we couldn't easily access the positional info from the EEG sensors, or that we decided not to spend the time properly parsing it, so this may not be a super straightforward fix.

Removed #todo

Removed comment # TODO: these EEGs aren't split appropriately in _left_right_sensors = ... in plot.py as part of #173/#184

[neukym]

@caiw - can you give more info of what this issue refers to? In the above plot, I can see that at least 28 sensors are attributed to the centre line (i.e. are outlined dots) - which I think is too many, is this what this issue refers to?

[caiw]

I'm not 100% sure to be honest :) I was removing the #todo as part of #184.

The current code looks like this:

_left_right_sensors: tuple[AxisAssignment, AxisAssignment] = (
    AxisAssignment(axis_name="left",
                   axis_channels=[
                       sensor
                       for sensor, (x, y) in get_meg_sensor_xy().items()
                       if x <= 0
                   ] + eeg_sensors()),
    AxisAssignment(axis_name="right",
                   axis_channels=[
                       sensor
                       for sensor, (x, y) in get_meg_sensor_xy().items()
                       if x >= 0
                   ] + eeg_sensors()),
)

So it looks as if the EEG sensors are all getting assigned to both hemis, which is how we are defining medial sensors at the moment:

# Symmetric difference
both_chans = top_chans & bottom_chans
top_chans -= both_chans
bottom_chans -= both_chans

So I assume the comment relates the fact that we aren't actually using the location of EEG sensors to assign them to left and right.

I'll amend the issue description accordingly.

[caiw]

@neukym Please add a file which maps from the sensor names in EEG1015.lay to the sensor names we use.

[neukym]

Done. Reassigning to @caiw.

[caiw]

Should be ready now