Under different circumstances, one neuron drives different behaviors in cricket, leech, and Aplysia ( Nolen and Hoy, 1984 Jing and Weiss, 2001 Esch et al., 2002 Morgan et al., 2002 Jing et al., 2004). However, research on other multifunctional networks questions the generality of this scheme.
(1985) provided a positive answer they applied the simple command neuron concept to multifunctional networks by suggesting that specialized command-like neurons drive and specify different behaviors. The question, then, is whether command neurons themselves subserve both functions, meaning do they both activate programs and specify their nature? Croll et al. Therefore, to initiate behavior, it does not suffice to simply trigger activity in the motor network-the type of program induced must also be specified. However, more recent work showed that pattern-generating networks activated by command neurons are often multifunctional that is, they generate multiple types of motor programs ( Nusbaum and Beenhakker, 2002 Jing and Weiss, 2005 Marder and Bucher, 2007 Briggman and Kristan, 2008 Benjamin, 2012). Initially, single command-like neurons were thought to drive single behaviors ( Wiersma and Ikeda, 1964 Frost and Katz, 1996 Edwards et al., 1999 Jing and Gillette, 1999 Eaton et al., 2001 Korn and Faber, 2005). These neurons have recently attracted a renewed interest because of the discovery of a command-like neuron in the feeding circuit of a genetic organism, Drosophila ( Flood et al., 2013). 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.Ĭommand-like interneurons are activated by appropriate inputs and in turn drive pattern-generating circuits to produce complex outputs ( Wiersma and Ikeda, 1964 Kupfermann and Weiss, 1978 Jing, 2009).
This effect may be mediated by specific actions that CBI-11 exerts on pattern-generating interneurons. Second, coactivation of CBI-11 with CBI-2 makes CBI-2 programs immediately ingestive. This effect appears to be partly mediated by CP2. First, prestimulation of CBI-2 enhanced the ability of CBI-11 to drive programs. Importantly, we found that CBI-2 and CBI-11 complement each other's actions. When it is successful, however, CBI-11 is an effective specifier of motor activity that is, it drives mostly ingestive programs. On its own, CBI-11 is therefore less effective as a program activator. Furthermore, it is weak in its ability to drive programs. Here, we show that CBI-11 differs from CBI-2 in that it contains FCAP but not CP2. The ability of CBI-2 to trigger motor activity has been attributed to the two program-promoting peptides it contains, FCAP and CP2. CBI-2 reliably generated ingestive patterns only when it was repeatedly stimulated.
#Activate sigmaplot 11 Activator#
Earlier work indicated that, in rested preparations, CBI-2, a powerful activator of programs, can trigger ingestive and egestive programs. 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. 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. Motor activity is often initiated by a population of command-like interneurons.