Cengiz B, et al. - The relationship between action observation (AO)-related corticomotor excitability changes and phases of observed action was investigated in this study. Moreover, the authors explored the effects of pure AO and concurrent AO and motor imagery (MI) state on corticomotor excitability using transcranial magnetic stimulation (TMS). They demonstrated that corticomotor excitability was modulated by different phases of the observed motor movement and this modulation was not muscle-specific. Compared to pure AO, simultaneous MI and AO enhanced corticomotor excitability significantly.