[FieldTrip] unit gain for Fieldtrip's LCMV beamformer - unit

[russ port]

Thanks Marc,

Sorry for taking so long to respond. I am quite confused now. I think I get what you are talking about with "unit gain" and "unit noise-gain” as defined by Sekihara, as much as I can make out at least with out having the book you refer to (on the bright side I now know what to nag my boss for). I suppose I was a quite mis-leading with what I had in my last email, by which, what I actually did was use the LCMV beamformer to make lead fields to calculate the virtual sensors (see http://www.fieldtriptoolbox.org/tutorial/shared/virtual_sensors <http://www.fieldtriptoolbox.org/tutorial/shared/virtual_sensors>). Of note, your link to the discussion list is now even more useful. I am using centimeters and a single shell head model. The wiki says "CMV beamformer spatial filter for the location of interest will pass the activity at that location with unit-gain”. From your email, I suspect then that the output would be in Am units. I am a little concerned though that both my output, and the field trip wiki shows values ranging ~ -3 -> 3 (e-4, i.e. mAm not nAm). Or instead would the units be in T/(Am) (if I apply the 1e4 unit conversion). Sorry for not being better at this, I think I do need those books you were mentioning...

Best,
Russ





> On Sep 11, 2015, at 12:40 PM, Marc Lalancette <marc.lalancette at sickkids.ca> wrote:
> 
> mformer with unit gain would have Am units.

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