Fig. 3. Electromyographic (EMG) activity from the right (RRB) and left (LRB) retractor bulbi muscles of Rana pipiens during swallowing. Black bars represent the duration of each eye retraction and were calculated from synchronized light video. Line drawings represent the position of the eyes during periods of relaxation (A,C) and during active retraction of the eyes (B,D). Note that bilateral EMG activity starts shortly before eye retraction begins and ends as the eyes return to their rest positions.