The result of evolutionary limb loss on the complement of motor neurons in a crayfish limb nerve revealed by serial homology

Drummond, Joanne; Jackson, David H.; Macmillan, David L.

doi:10.1080/10236249809387068

Cited by 4 publications

(1 citation statement)

References 16 publications

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“…Even in animals that lack swimmerets on the first abdominal segment, there are neurons with axons in the ganglion's N1 that look like swimmeret motor neurons. Drummond et al (1998) used cobalt backfilling methods in Cherax destructor to compare the population of neurons in A1 with those in ganglia that innervate unmodified swimmerets and reported that the numbers of neurons in A1 were much reduced. Page (1985) used similar methods to compare the innervation of the sexually-dimorphic swimmerets of Homarus americanus .…”

Section: Modular Organization and Local Circuits In The Cnsmentioning

confidence: 99%

Neurobiology of the crustacean swimmeret system

Mulloney

Smarandache‐Wellmann

2012

Progress in Neurobiology

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The crustacean swimmeret system includes a distributed set of local circuits that individually control movements of one jointed limb. These modular local circuits occur in pairs in each segmental ganglion, and normally operate synchronously to produce smoothly coordinated cycles of limb movements on different body segments. The system presents exceptional opportunities for computational and experimental investigation of neural mechanisms of coordination because: a. The system will express in vitro the periodic motor pattern that normally drives cycles of swimmeret movements during forward swimming. b. The intersegmental neurons which encode information that is necessary and sufficient for normal coordination have been identified, and their activity can be recorded. c. The local commissural neurons that integrate this coordinating information and tune the phase of each swimmeret are known. d. The complete set of synaptic connections between coordinating neurons and these commissural neurons have been described. e. The synaptic connections onto each local pattern-generating circuit through which coordinating information tunes the circuit's phase have been discovered. These factors make possible for the first time a detailed, comprehensive cellular and synaptic explanation of how this neural circuit produces an effective, behaviorally-significant output. This paper is the first comprehensive review of the system's neuroanatomy and neurophysiology, its local and intersegmental circuitry, its transmitter pharmacology, its neuromodulatory control mechanisms, and its interactions with other motor systems. Each of these topics is covered in detail in an attempt to provide a complete review of the literature as a foundation for new research. The series of hypotheses that have been proposed to account for the system's properties are reviewed critically in the context of experimental tests of their validity.

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Section: Modular Organization and Local Circuits In The Cnsmentioning

confidence: 99%

Neurobiology of the crustacean swimmeret system

Mulloney

Smarandache‐Wellmann

2012

Progress in Neurobiology

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Functional organization of crayfish abdominal ganglia. III. Swimmeret motor neurons

Mulloney

Hall

2000

J. Comp. Neurol.

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Embryonic and postembryonic neurogenesis in the ventral nerve cord of the freshwater crayfish Cherax destructor

Sullivan

Macmillan

2001

J. Exp. Zool.

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Previous studies of neurogenic activity in the thoracic neuromeres of indirect developing crustaceans indicated that the temporal patterns of neurogenesis can be correlated with the appearance of the thoracic appendages during larval and metamorphic development. To test further the idea that the temporal patterns of neurogenesis in crustaceans are related to their life histories, we examined neurogenesis in the ventral nerve cord of a direct developing crustacean, the freshwater crayfish Cherax destructor, whose life history contains neither larval stages nor metamorphoses. Neurogenesis was examined using the in vivo incorporation of bromodeoxyuridine into DNA. During late embryonic development the thoracic neuromeres of the crayfish contain arrays of mitotically active neuroblasts similar to those previously described in the spider crab and lobster. The arrays in the crayfish abdomen are, however, greatly reduced compared with those of the thorax. On hatching, both the thoracic and abdominal appendages of C. destructor are capable of movement. The pleopods, however, do not beat rhythmically until the second postembryonic stage whereas the pereiopods are not used in coordinated walking movements until the third stage. An examination of the time course of neurogenesis in the ventral nerve cord revealed that neurogenic activity in each neuromere ceases during or before the moult to the developmental stage in which its segmental appendage is first used in coordinated movements. These findings indicate that the patterns of neurogenesis in crustaceans are indeed related to the maturation of the segmental appendages and, in particular, to the maturation of motor behaviours.

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The result of evolutionary limb loss on the complement of motor neurons in a crayfish limb nerve revealed by serial homology

Cited by 4 publications

References 16 publications

Neurobiology of the crustacean swimmeret system

Neurobiology of the crustacean swimmeret system

Functional organization of crayfish abdominal ganglia. III. Swimmeret motor neurons

Embryonic and postembryonic neurogenesis in the ventral nerve cord of the freshwater crayfish Cherax destructor

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