Fig. 2. Results from the eight individual animals with intact spinal cords and rostrally pinned that were successfully tested in both conditions: trunk with muscle (Muscle) and isolated spinal cord and notochord (Cord). Each symbol represents the same animal in all graphs. (A) , the average of the rostral and caudal bursting frequencies. In cases in which the rostral and caudal outputs had different frequencies, the average of the two frequencies is plotted. (B) /, the rostral/caudal frequency ratio. (C) /n, the phase lag per segment between rostral and caudal outputs. (D) ß, the coupling strength parameter describing the functional coupling strength between rostral and caudal recording locations. The value ß=0 corresponds to no coupling, and the value ß=1 corresponds to infinite strength coupling. Error bars represent approximate 95% confidence intervals. In one case (open circles in the muscle condition), we were unable to compute confidence intervals because ß=1.