title: Complementary interactions between command-like interneurons that function to activate and specify motor programs.
abstract: Motor activity is often initiated by a population of command-like interneurons. Command-like interneurons that reliably drive programs have received the most attention, so little is known about how less reliable command-like interneurons may contribute to program generation. We study two electrically coupled interneurons, cerebral-buccal interneuron-2 (CBI-2) and CBI-11, which activate feeding motor programs in the mollusk Aplysia californica. Earlier work indicated that, in rested preparations, CBI-2, a powerful activator of programs, can trigger ingestive and egestive programs. CBI-2 reliably generated ingestive patterns only when it was repeatedly stimulated. The ability of CBI-2 to trigger motor activity has been attributed to the two program-promoting peptides it contains, FCAP and CP2. Here, we show that CBI-11 differs from CBI-2 in that it contains FCAP but not CP2. Furthermore, it is weak in its ability to drive programs. On its own, CBI-11 is therefore less effective as a program activator. When it is successful, however, CBI-11 is an effective specifier of motor activity; that is, it drives mostly ingestive programs. Importantly, we found that CBI-2 and CBI-11 complement each other's actions. First, prestimulation of CBI-2 enhanced the ability of CBI-11 to drive programs. This effect appears to be partly mediated by CP2. Second, coactivation of CBI-11 with CBI-2 makes CBI-2 programs immediately ingestive. This effect may be mediated by specific actions that CBI-11 exerts on pattern-generating interneurons. Therefore, different classes of command-like neurons in a motor network may make distinct, but potentially complementary, contributions as either activators or specifiers of motor activity.
authors.affiliation: Department of Neuroscience and Friedman Brain Institute, Mount Sinai School of Medicine, New York, New York 10029, and State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Jiangsu 210093, China.
authors.forename: Jin-Sheng
authors.initials: JS
authors.lastname: Wu
authors.forename: Nan
authors.initials: N
authors.lastname: Wang
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Siniscalchi
authors.forename: Matthew H
authors.initials: MH
authors.lastname: Perkins
authors.forename: Yu-Tong
authors.initials: YT
authors.lastname: Zheng
authors.forename: Wei
authors.initials: W
authors.lastname: Yu
authors.forename: Song-an
authors.initials: SA
authors.lastname: Chen
authors.forename: Ruo-nan
authors.initials: RN
authors.lastname: Jia
authors.forename: Jia-Wei
authors.initials: JW
authors.lastname: Gu
authors.forename: Yi-Qing
authors.initials: YQ
authors.lastname: Qian
authors.forename: Yang
authors.initials: Y
authors.lastname: Ye
authors.forename: Ferdinand S
authors.initials: FS
authors.lastname: Vilim
authors.forename: Elizabeth C
authors.initials: EC
authors.lastname: Cropper
authors.forename: Klaudiusz R
authors.initials: KR
authors.lastname: Weiss
authors.forename: Jian
authors.initials: J
authors.lastname: Jing
mesh_terms: D000818:Animals; D001048:Aplysia / Q000502:physiology*; D002610:Cheek / Q000294:innervation / Q000502:physiology; D003627:Data Interpretation, Statistical; D004435:Eating / Q000502:physiology; D004525:Efferent Pathways / Q000502:physiology*; D055724:Electrophysiological Phenomena / Q000502:physiology; D005247:Feeding Behavior / Q000502:physiology; D005502:Food; D007150:Immunohistochemistry; D007395:Interneurons / Q000502:physiology*; D009043:Motor Activity / Q000502:physiology*; D009479:Neuropeptides / Q000502:physiology; D018408:Patch-Clamp Techniques
chemical_list: D009479:Neuropeptides
keywords: Aplysia; central pattern generator; command neurons; electrical coupling; feeding; population coding