The abdominal motor system of the crayfish, Cherax destructor . II. Morphology and physiology of the deep extensor motor neurons

Drummond, Joanne; Macmillan, David L.

doi:10.1007/s003590050285

Cited by 11 publications

(9 citation statements)

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“…The anterior branch (N2a) contains tactile afferents ( Leise, Hall & Mulloney, 1987 ). The posterior branch (N2p) contains fast extensor motor neurons ( Treistman & Remler, 1975 ; Drummond & Macmillan, 1998a ), slow extensor motor neurons ( Drummond & Macmillan, 1998b ), and neurons associated with muscle receptor organs (MROs) ( Leise, Hall & Mulloney, 1987 ).…”

Section: Resultsmentioning

confidence: 99%

“…Reasonable hypotheses about the identity of cell bodies can be based on their sizes and putative homology with other species ( Table 3 ). Fast extensor motor neurons are usually double or more the diameter of slow extensor motor neurons ( Otsuka, Kravitz & Potter, 1967 ; Wine & Hagiwara, 1977 ), although the largest slow extensor motor neurons approach the size of the smallest fast extensor neuron ( Wine & Hagiwara, 1977 ; Drummond & Macmillan, 1998a ; Drummond & Macmillan, 1998b ). Fills of N2p revealed four large cell bodies located along the posterior margin of the ganglion, one contralateral and three ipsilateral, which are putative fast extensor motor neurons.…”

Section: Resultsmentioning

confidence: 99%

“… b Leise, Hall & Mulloney, 1987 . c Drummond & Macmillan, 1998a ; Drummond & Macmillan, 1998b . d FEMNs: Otsuka, Kravitz & Potter, 1967 , SEMNs: Jones & Page, 1983 .…”

Section: Resultsmentioning

confidence: 99%

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Motor neurons in the escape response circuit of white shrimp (Litopenaeus setiferus)

Faulkes

2015

PeerJ

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Many decapod crustaceans perform escape tailflips with a neural circuit involving giant interneurons, a specialized fast flexor motor giant (MoG) neuron, populations of larger, less specialized fast flexor motor neurons, and fast extensor motor neurons. These escape-related neurons are well described in crayfish (Reptantia), but not in more basal decapod groups. To clarify the evolution of the escape circuit, I examined the fast flexor and fast extensor motor neurons of white shrimp (Litopenaeus setiferus; Dendrobranchiata) using backfilling. In crayfish, the MoGs in each abdominal ganglion are a bilateral pair of separate neurons. In L. setiferus, the MoGs have massive, possibly syncytial, cell bodies and fused axons. The non-MoG fast flexor motor neurons and fast extensor motor neurons are generally found in similar locations to where they are found in crayfish, but the number of motor neurons in both the flexor and extensor pools is smaller than in crayfish. The loss of fusion in the MoGs and increased number of fast motor neurons in reptantian decapods may be correlated with an increased reliance on non-giant mediated tailflipping.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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Motor neurons in the escape response circuit of white shrimp (Litopenaeus setiferus)

Faulkes

2015

PeerJ

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“…The fast extensor motor neurons are variable across crayfish species. There are six fast extensors per ganglion in P. clarkii [Wine and Hagiwara, 1977] and C. destructor [Drummond and Macmillan, 1998], but eight in P. leniusculus [Leise et al, 1987]. These differences have no obvious functional consequences, because crustacean muscle fibers are often innervated by multiple motor neurons, whose innervation often overlaps substantially [Atwood, 1976].…”

Section: Faulkesmentioning

confidence: 99%

Turning Loss Into Opportunity: The Key Deletion of an Escape Circuit in Decapod Crustaceans

Faulkes¹

2008

Brain Behav Evol

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Decapod crustacean escape responses are adaptive behaviors whose neural bases are well understood. The escape circuit is composed of giant neurons. Lateral giant interneurons (LGs) respond to posterior stimuli by generating a somersaulting tailflip; medial giant interneurons (MGs) respond to anterior stimuli with a backwards tailflip. Both sets of interneurons connect to giant fast flexor motor neurons (MoGs). Most features of the escape circuit are thought to result from strong selective pressure to respond to stimuli in the shortest possible time. Despite the apparent advantages of the escape circuit, it has been lost in multiple taxa independently. Some losses of the escape circuit may be rare cases of disaptation, where organisms are less well adapted than related species (i.e., those with the escape circuit). The losses of the escape circuit might be key deletions that promoted the radiation of decapod crustaceans by increasing selection pressure for species to evolve new anti-predator strategies and removing constraints against change.

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“…This was a straightforward plan and could have worked in principle. In practice, however, it was difficult to apply because action potential size is an unreliable indicator of neuron identity, especially where there are many neurons of similar size, as there are in the second nerve branches to the SRs (Sokolove, 1973; Sokolove and Tatton, 1975; Drummond and Macmillan, 1998a, b). Several authors have commented that neither axonal and neuronal body size nor cross‐correlation between dye fills and extracellular recordings is a reliable identifier in these neurons (Wine and Hagiwara, 1977; Bastiani, 1981; Liese et al, 1987; Bastiani and Mulloney, 1988; Drummond, 1996).…”

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Morphology and connections of the abdominal accessory neurons of the crayfish Cherax destructor

Drummond

Macmillan

2004

J of Comparative Neurology

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Associated with the abdominal muscle receptor organs of crayfish are accessory neurons that inhibit the activity of the stretch receptors. Cobalt infusion into their cut axons reveals four accessory somata associated with each hemiganglion in the abdomen of the crayfish Cherax destructor. These conform to the pattern described previously for these neurons: The cell bodies are in the ganglion posterior to the one from which they exit. We recorded intracellularly from the largest accessory neurons, Acc-1 and Acc-2, and stained them with intracellular dye to establish unambiguously the characteristics defining their identity and structure. We describe their branching patterns in the ganglion of origin and the ganglion of exit. This morphological information permitted us to distinguish all four accessory neurons in preparations with dye infused through their cut axons, and we propose a revised, unambiguous nomenclature for the two smaller ones. Our intracelluar recordings allowed us to reexamine the physiological relationships of Acc-1 and Acc-2, the only accessory neurons for which there are data in the literature. In general, the connections and inputs described in previous studies were substantiated, although there has clearly been confusion between the two, and they differ in a number of significant ways. We found that they are seldom active together, have different firing patterns, and may operate with different clusters of extensor and flexor motorneurons. The results illustrate the level at which the accessory neurons operate within the abdominal control system but do not distinguish between competing hypotheses concerning their role in behavior. The data are consistent with the view that accessory neurons assist in timing between adjacent segments.

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The abdominal motor system of the crayfish, Cherax destructor . II. Morphology and physiology of the deep extensor motor neurons

Cited by 11 publications

References 0 publications

Motor neurons in the escape response circuit of white shrimp (Litopenaeus setiferus)

Motor neurons in the escape response circuit of white shrimp (Litopenaeus setiferus)

Turning Loss Into Opportunity: The Key Deletion of an Escape Circuit in Decapod Crustaceans

Morphology and connections of the abdominal accessory neurons of the crayfish Cherax destructor

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