Figure 2.

Effect of methoxamine on alternating activity in the lumbosacral cord. A: Left: The addition of the α₁-adrenergic agonist (methoxamine) to the 5-HT/DA/NMDA cocktail, in the same experiment as Fig. 1B, produces a seemingly synchronized high-amplitude activity in all ventral roots. Middle: Each one of these episodes of synchronous activity is a cluster of short bursts. Right: This clustered activity is composed of short alternating bursts between the left and right sides; with the lumbar bursts in phase with sacral bursts on the same side of the cord (notice the different time scales). B: An episode of fast, alternating activity produced by the same chemical cocktail in a spinal cord of a P15 mouse. Note that burst duration and cycle are similar to the experiment in (A). C: The burst parameters after methoxamine administration, plotted as a percentage of the value before adding the drug. The bars represent the mean ± standard deviation. * Statistically significant, p value < 0.05.