How the XXXX locomotor region recruits hindbrain neurons.

@entity717 @entity3308 @entity7928
This chapter summarizes experiments which were designed to reveal how repetitive electrical stimulation of the @entity3308 locomotor region (MLR) recruits nearby hindbrain neurons into activity, such that locomotion can ensue in the @entity7928 salamander, A. tigrinum. The MLR stimulus strength was subthreshold or near-threshold for @entity717 to ensue. Such relatively weak stimulation of the MLR produced @entity717 after a relatively long delay, which featured neuronal interactions in the hindbrain. MLR-evoked spike responses of single hindbrain neurons were recorded before @entity717 began. This allowed consideration of the build-up of the hindbrain neuronal activity, which was subsequently impressed upon the spinal cord such as to evoke @entity717 . Each train of MLR stimulus pulses evoked monosynaptic responses in but a small proportion of the hindbrain's neurons. Rather, oligosynaptic responses were routinely evoked, even in the "input" neurons that were activated monosynaptically. Consecutive stimulus volleys recruited a given neuron after a variable number of synaptic translations. It is argued that the hindbrain's input neurons excited a much larger number of other hindbrain neurons. By this means, an MLR-evoked, short-lived propagating wave of excitation (i.e., approximately 2-4 successive synaptic activations) can be spread throughout the hindbrain.
