Figure 2From: Quadriceps arthrogenic muscle inhibition: the effects of experimental knee joint effusion on motor cortex excitabilityRectified motor evoked potential (MEP) recorded from the quadriceps during active muscle contraction. Note the stimulus artefact (initial large positive deflection) followed by the larger polyphasic MEP and then the silent period in the ongoing EMG following the MEP (cortical silent period).Back to article page