cursor task problems

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paolobernardis
Posts: 40
Joined: 02 Jul 2010, 04:51

cursor task problems

Post by paolobernardis » 27 Nov 2010, 08:47

Dear all, :D

we made different trials of cursor moving task (1D/2D/3D with different number of targets), always following your tutorial step by step.
Nevertheless, we observed that in all our trials the cursor began its movement independently from the user's intention (it seemed it had a movement "by chance"). In the latest trial we would like to have an horizontal movement of the cursor (from left to the right) using C4 as unique input channel (left hand had the best r^2 value) and applying a small Laplacian spatial filter and a "full matrix"(1row and 5 columns in the "spatial filter matrix").
Our parameters file for 1D feedback task with 1 target has the following data:
- in the "linear classifier matrix":

C4_OUT | 11Hz | 1 | 1 |

- in the normalizer section, following the tutorial "trial based 1D feedback task", we set these values:
normalizer offsets = -1
normalizer gains = 2
adaptation = 1

-in the "buffer condition matrix":

(Feedback==1)&&(TargetCode==1)

How can avoid this unvoluntary cursor movements? Did we make any error in one of these parameters?
A last, hopefully easier question: despite this problem, in all the trials we had a result such as "100%correct" and bits transferred were between 0 and 12.
Why we ALWAYS have "100%correct", even if we didn't reach the target, and we didn't transfer any bit?
We read the tutorial, but we couldn't find in it any information regarding this problems. Hopefully, you could help us in the best way!

Thank you so much in advance,

Best regards.

mellinger
Posts: 1056
Joined: 12 Feb 2003, 11:06

Post by mellinger » 29 Nov 2010, 05:54

Dear Paolo,
How can avoid this unvoluntary cursor movements? Did we make any error in one of these parameters?
some amount of random cursor movement will always be present, due to noise. However, it could also be that your problems are due to a bug in BCI2000. Please download the latest version from
http://bci2000.org/downloads/bin/BCI200 ... 101124.exe
before repeating your experiment.
Why we ALWAYS have "100%correct", even if we didn't reach the target, and we didn't transfer any bit?
You are right, this should not be the case. I verified that the reporting of error rates is correct in recent versions of BCI2000.

Best regards,
Juergen

sonidaman
Posts: 10
Joined: 15 Sep 2011, 00:44

Re: cursor task problems

Post by sonidaman » 26 Jan 2012, 08:54

hi paolo,
i m doing my project in 2D cursor movement using EEG signal.i have read tht u got success in 1D/2D/3D/ cursor movement.so i need your help about my 2D cursor movement.i need all information regarding 2D cursor movement.plz reply me as soon as possible.
thnx in advance.

gschalk
Posts: 615
Joined: 28 Jan 2003, 12:37

Re: cursor task problems

Post by gschalk » 26 Apr 2012, 12:16

Paolo,

Expanding on Juergen's post, I am curious whether you may have only defined one target? I think you probably need to define at least two.

Gerv

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