Dear HCP experts, When looking to tmegpreproc data, during motor task and with trials locked on the onset of the flashing cross (TFLA files), I am quite surprised to observe that the EMG signal sometimes triggers before the onset of the flashing cross in some trials.
To be more specific, let us consider the right hand trials of subject 104012 in the first run. In attachment you will find the EMG signal of trial 4 (KO.png) and 8 (OK.png), after high-pass Butterworth filtering at 10Hz, and taken in absolute value. On the X-axis, time step 611 (i.e. the center of the time window) corresponds to the onset of the flashing cross. However, we observe on the KO.png figure that the EMG triggers before this time step, although it should follow the stimulus, not precede it... I have been able to observe this in many trials, as well as in data related to other subjects. Where does this come from? Or am I missing something? Besides, it seems that the TEMG alignment is more reliable. Thank you in advance for your help ! Benjamin _______________________________________________ HCP-Users mailing list [email protected] http://lists.humanconnectome.org/mailman/listinfo/hcp-users
