how to produce plot with P300 Speller?

[Yueqing Li]

Hi, Dr. Schalk:

When I run the "example.m" file in matlab, although plot can be produced, but there are some alerts---
"??? Index exceeds matrix dimensions.

Error in ==> topoplot at 215
Vl = Vl(ii);

Error in ==> p3 at 196
topoplot(data2plot, eloc_file, 'maplimits', [displaymin, displaymax], 'style', 'straight');

Error in ==> example at 23
[res1ch, res2ch, ressqch, stimdata] = p3('Yueqing0723S001R02.mat', 240, 11, 650, 1, 1, [270 310 350 390 430 470], [3 2], 'eloc64.txt', '');
".

Is something wrong with my data file? Or maybe I use incorrect parameters in P3 function (I have not changed the default parameter you set, except the data file name).

Thank you

[gschalk]

Yueqing,

Change the 2nd parameter (sampling rate) from 240 to 256. I think you use 256 Hz.

Also, change 'eloc64.txt' to 'eloc16.txt' since you only use 16 channels. However, do not pay attention to the topographies since your montage and channel assignment are most likely different than those in the eloc16 file. To get correct topographies, you would need to create an appropriate electrode location file.

Gerv

[Yalda Shahriari]

Hi,
I wanted to know how can I download eloc16.txt. I have just eloc64.txt.

Regards
Yalda Shahriari

[Yalda Shahriari]

Hi,
As I work with gUSB amp (gtech company) it has just 16 channel for recording I wanted to know how can I download eloc16.txt. I have just eloc64.txt.
Please guide me.

Regards
Yalda Shahriari

[mellinger]

Hi,

there is no eloc16.txt that is correct under all circumstances. Rather, you will need to create your own eloc file by making a copy of eloc64.txt, and then remove all electrodes that are not present in your setup. Finally, make sure that the order of electrodes in the new eloc file matches the order in which physical electrodes are connected to the physical channels of your amplifier.

Regards,
Juergen