AUTHOR=Sharples Simon A. , Koblinger Kathrin , Humphreys Jennifer M. , Whelan Patrick J. TITLE=Dopamine: a parallel pathway for the modulation of spinal locomotor networks JOURNAL=Frontiers in Neural Circuits VOLUME=8 YEAR=2014 URL=https://www.frontiersin.org/journals/neural-circuits/articles/10.3389/fncir.2014.00055 DOI=10.3389/fncir.2014.00055 ISSN=1662-5110 ABSTRACT=
The spinal cord contains networks of neurons that can produce locomotor patterns. To readily respond to environmental conditions, these networks must be flexible yet at the same time robust. Neuromodulators play a key role in contributing to network flexibility in a variety of invertebrate and vertebrate networks. For example, neuromodulators contribute to altering intrinsic properties and synaptic weights that, in extreme cases, can lead to neurons switching between networks. Here we focus on the role of dopamine in the control of stepping networks in the spinal cord. We first review the role of dopamine in modulating rhythmic activity in the stomatogastric ganglion (STG) and the leech, since work from these preparations provides a foundation to understand its role in vertebrate systems. We then move to a discussion of dopamine’s role in modulation of swimming in aquatic species such as the larval xenopus, lamprey and zebrafish. The control of terrestrial walking in vertebrates by dopamine is less studied and we review current evidence in mammals with a focus on rodent species. We discuss data suggesting that the source of dopamine within the spinal cord is mainly from the A11 area of the diencephalon, and then turn to a discussion of dopamine’s role in modulating walking patterns from both