Example of full, partial, and absent StartReact (SR) responses. A: full SR response with a completed anticipatory postural adjustment (APA)-reach sequence as shown by anterior displacement of the hand (1st window), posterior center of pressure (CoP) displacement (2nd window), and corresponding muscle activation (3rd–5th windows) after the loud acoustic stimulus (LAS) and before the go cue. B: partial SR response with SR response only in APA as shown by posterior CoP displacement and tibialis anterior (TA) activation between the LAS and go cue. C: absent SR response with neither SR response in APA onset nor SR response in reach. T0 represents the timing of the warning cue. T1 represents the timing of the LAS. T2 represents the timing of the go cue. Note that the LAS is at −200 ms relative to the go cue. AD, anterior deltoid; LTA, left TA; RTA, right TA.