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. 2013 Jul 17;33(29):12013–12029. doi: 10.1523/JNEUROSCI.1060-13.2013

Figure 1.

Figure 1.

The gastric mill protraction neuron LG generates different activity patterns during the VCN-triggered and POC-triggered gastric mill rhythm. A, Schematic of the isolated stomatogastric nervous system, including its four ganglia plus the connecting nerves and a subset of peripheral nerves. The VCNs project into the CoGs from the cardiac sac stomach compartment via the dpon and superior oesophageal nerve (son). The POC neurons project into the CoGs via the poc nerve and the cocs (coc). The LG neuron axon projects through the dvn, lvns, and lgns to innervate its muscle targets (Fig. 1B). OG, oesophageal ganglion; TG, thoracic ganglion; ion, inferior oesophageal nerve; mvn, medial ventricular nerve; pdn, pyloric dilator nerve; stn, stomatogastric nerve. B, Schematic dorsal view of the posterior region (right half) of a dissected C. borealis foregut (modified from Weimann et al., 1991). LG innervates several protractor muscles (gray shading), including gm8a, gm6ab, and gm5b, via the lvn and lgn. C, Gastric mill motor patterns triggered by brief stimulation of the POC and VCN pathways and recorded extracellularly from nerves shown schematically in A. No gastric mill rhythm was in progress before either pathway was stimulated, but the pyloric rhythm was ongoing (pdn, control). Note that the MCN1 and LG neuron burst patterns were pyloric rhythm-timed (see pdn) during the POC-triggered gastric mill rhythm but were tonic during the protraction phase of the VCN-triggered gastric mill rhythm. The POC-triggered and VCN-triggered gastric mill rhythms were recorded in separate preparations. The control recording shown was from the POC preparation. Boxed regions are expanded in D. PRO, Protraction; RET, retraction. Modified from White and Nusbaum (2011). D, Expanded region from C of the pdn and lgn recordings, showing the lack of pyloric (PD)-timed activity within the LG burst during the VCN-triggered gastric mill rhythm (Post-VCN stim.) and the presence of pyloric-timed interruptions within the LG burst (arrowheads) during the POC rhythm (Post-POC stim.).