Figure 1.
The sequence of events for one typical trial.
The closures of two switches initiate the trial and trigger the illumination of the fixation point (FP). In this example, a side grip (two left LEDs) is required to reach, grasp and pull a heavy (two top LEDs) object. For each pre-cueing condition (ALL, GRIP, FORCE, NO), presented in separate block, the GO systematically provides the combined information about the required grip and force. When the object has been held for 1 s, the GO and FP extinction indicates the end of the trial.
Figure 2.
A: Time-frequency maps averaged across all conditions for 3 typical subjects (electrode C3).
For all the subjects, the modulations in beta power were maximal in the 15–25 Hz frequency band. B: Topographic maps (grand average) of the ERD/ERS modulations expressed in percentages compared to the baseline (0 %) as a function of pre-cueing conditions. Each map represents the averaged signal for a 200 ms time window. C: Averaged ERD/ERS traces as a function of pre-cueing conditions for the 5 electrodes of interest (Cz, CPz, Pz, C3, C4). The two vertical dotted lines represent the cue and GO onsets respectively. The 4 short horizontal bars represent the 4 time windows used for statistical analyses.
Figure 3.
ERD/ERS traces as a function of behavioral responses for the electrode C3 and each pre-cueing condition.
The two vertical dotted lines represent cue and GO onsets respectively. PG + HF: precision grip and high force, PG + LF: precision grip and low force, SG + HF: side grip and high force, SG + LF: side grip and low force. The 4 short horizontal bars represent the 4 time windows used for statistical analyses. For visual purposes, data in the figure were Gaussian-convolved with a 500 ms window.