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. 2013 May 7;8(5):e63417. doi: 10.1371/journal.pone.0063417

Figure 4. Summary of the effects of a startling acoustic stimulus (SAS) on the release of movement.

Figure 4

A. Single trial examples of the elbow joint displacement and rectified EMG activity in biceps brachii (BB) and extensor digitorum communis (EDC) muscles when movement was initiated in response to the imperative tone (control trial, black line) or in response to a SAS presented 500 ms before the release tone (red line). Note that the kinematics and muscle activation patterns (the BB EMG suppression is highlighted with a grey bar) for the SAS-evoked movement were unchanged from control trials but the sequence was initiated less than 100 ms after the startle stimulus. B. The incidence of release of the movement sequence by a SAS was significantly affected by the temporal probability of imperative cue. For the PREDICT condition, the average incidence of release progressively increased from 0% of trials at −3500 ms (warning cue) to over 80% at −100 and 0 ms. In contrast, the incidence of release was relatively constant across all stimulus timings for the REACT condition. C. Examples of the incidence of movement release as a function of the timing of the SAS across three subjects (S1, S2, S3). For the PREDICT task, all subjects showed a similar profile of increasing incidence of release. In contrast, the behavior for the REACT task was different across subjects. S1 rarely released, S3 released on nearly every trial and S2 released in approximately 60% of trials, irrespective of timing of the SAS.