Fig 5. Implicit observation condition.

(A) H-reflex modulation recorded in the right FCR muscle of 14 right-handed observers, during observation of one cycle of a flexion-extension movement of the mover’s right hand (B, average movement trace performed by the mover in all different experiments (±SEM)), when observers are instructed to count how many times in each trial the LED light on the moving hand was flashed. In panel A the cumulative plot of the average data points from all subjects is fitted with a common sinusoid equation with the same period as that fitting the average movement. Note the reduced scale of the ordinate compared to Fig 2A. Δϕ: phase difference between reflex modulation in flexor muscle of the observer and hand oscillation of the mover. Flex = downward direction of the moving hand.