Supplementary Figure 4: Determining the source of wrist afferent feedback that tunes the biceps spinal reflex

a, Mean rectified biceps EMG activity when the wrist extensors were pre-excited prior to the mechanical perturbation (experiment 5; n = 20). Green and blue traces represent wrist perturbations that flexed and extended the wrist, respectively. Data is aligned to perturbation onset. Shading represents ± 1 s.e.m. b, Mean rectified biceps EMG activity in the spinal stretch reflex epoch for when the perturbation flexed (F) or extended (E) the wrist. Thin grey lines represent individual participants and the thick black line represents the group mean. The biceps spinal stretch reflex was not influenced by the perturbations applied at the wrist (t(14) = -1.13 p = 0.28, Cohen’s d = 0.29, 95% CI [-0.15 -0.05]).