Fig. 2. (Ai) In the neonatal mouse, electrical stimulation (4 Hz, 40 pulses) of the cauda equina is capable of evoking coordinated lumbar locomotor-like activity. (Aii) Rectified and filtered neurogram traces recorded from the second and fifth lumbar ventral roots (L2 and L5, respectively). These traces display both left-right (see L2-L2 and L5-L5 traces) and flexor-extensor (see ipsilateral L2-L5 traces) alternation. This pattern is considered to be a signature of locomotor-like activity. (Bi) A schematic of the recording procedure used to examine coordination between cervical and lumbar segments. (Bii) These digitally rectified and filtered traces show left-right alternation in the cervical roots (C8) that is coupled with the pattern recorded from the L2 neurograms. l, left; r, right.