Specializations in the lumbosacral vertebral canal and spinal cord of birds: evidence of a function as a sense organ which is involved in the control of walking

Necker, Reinhold

doi:10.1007/s00359-006-0105-x

Cited by 51 publications

(85 citation statements)

References 31 publications

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“…Mas, apesar de descritas para anatídeos (Necker 2006), não foram observadas fusões entre as vértebras torácicas em nenhuma espécie do gênero Amazona (Fig.7), fato que pode ser explicado pela presença de largos ligamentos interespinhosos, entre os processos espinhosos (Jiang et al 1995).…”

Section: Resultsunclassified

Descrição anatômica de esqueletos de papagaios do gênero Amazona através da utilização de radiografias

Cavinatto

Armando²,

Cruz

et al. 2016

Pesq. Vet. Bras.

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RESUMO.-O esqueleto de papagaios da espécie Amazona aestiva foi descrito e comparado com representantes de outras espécies do gênero Amazona. Para tanto, foram utilizados 22 exemplares da espécie Amazona aestiva; dois das espécies Amazona vinacea; Amazona rhodocorythae, Amazona farinosa, além de um exemplar das espécies Amazona brasiliensis e Amazona pretrei, doados após morte natural pelo Criadouro Poços de Caldas. Foram realizadas radiografias de corpo inteiro, variando de decúbito lateral direito ou esquerdo, no caso das projeções latero-laterais, e em decúbito dorsal, no caso da projeção ventro-dorsal. Independentemente da espécie, os crânios dos papagaios estudados puderam ser classificados como pró-cinéticos, por apresentarem liberdade de movimentos em sua porção rostral. Na maioria dos casos, a coluna vertebral esteve formada por 12 vértebras cervicais, seis vértebras torácicas livres, sinsacro (formado pela fusão da última vértebra torácica, 7 lombosacrais e uma caudal), cinco vértebras caudais livres e pelo pigóstilo (formado por três vértebras caudais fusionadas) e, apesar de diferenças pontuais, o esqueleto apendicular torácico e pélvico se mostrou muito semelhante ao observado para outros gêneros de aves e, inclusive, não foi possí-vel observar dimorfismo sexual através das características anatômicas dos esqueletos dos papagaios trabalhados. This study describes the skeleton of Amazona aestiva parrots and compared it with representatives of other Amazona species. To this end, we used 22 specimens of Amazona aestiva, two specimens each of Amazona vinacea; Amazona rhodocorythae, Amazona farinosa and one specimen each of Amazona brasiliensis and Amazona pretrei donated after natural death by Poços de Caldas Breeding Park. Full body radiographs were taken, in either the right or left lateral decubitus position, in the case of laterolateral projections, and in supine position, in the case of ventrodorsal projection. Regardless of the species, skulls of the parrots were classified as prokinetic, because of free movements in their rostral portion. In most cases, the spine consisted of: 12 cervical vertebrae, six free thoracic vertebrae, synsacrum (formed by the fusion of the last thoracic vertebrae, 7 lumbosacral vertebrae and one caudal vertebrae), five free caudal vertebrae and the pygostyle (formed by three fused caudal vertebrae). Despite punctual differences, thoracic and pelvic appendicular skeleton proved to be very similar to that observed for other genera of birds. In addition, there was no sexual dimorphism considering the anatomical characteristics of the skeletons of parrots analyzed.

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Section: Resultsunclassified

Descrição anatômica de esqueletos de papagaios do gênero Amazona através da utilização de radiografias

Cavinatto

Armando²,

Cruz

et al. 2016

Pesq. Vet. Bras.

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“…It has been suggested long ago that a special balance-sensing organ of the body is necessary during walking, because their hindlimbs are located at the rear of the gravity center, and some evidence supported this idea (1,3). At present, the proposed location of such an organ is the lumbosacral region of the vertebrae (14).…”

mentioning

confidence: 99%

Chick spinal accessory lobes contain functional neurons expressing voltagegated sodium channels generating action potentials

2008

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Ten pairs of protrusions, called accessory lobes (ALs), exist at the lateral sides of avian lumbosacral spinal cords. Histological evidence has shown that neurons are present in AL and behavioral evidence suggests that AL acts as a sensory organ of equilibrium during bipedal walking. However, there is little functional evidence to indicate that cells in AL have neuronal functions. To elucidate this point, we developed a method to dissociate cells from chick AL and made electrophysiological recordings with the whole-cell patch clamp technique. Cells dissociated by enzymatic digestion from chick AL contained two major types of cells. One was round with clear cytosol and the other had a round cell body, rich cytosolic structures and some processes. Rapidly activating inward currents and slowly activating outward currents were recorded in response to depolarizing pulses to −10 mV under the voltage clamp configuration only from the latter type of cells. TTX at 100 nM inhibited the inward current by 85%, indicating the functional expression of TTX-sensitive voltage-gated Na + channel (VGSC). Activation and inactivation kinetics of the inward currents in AL cells were similar to those of mammalian VGSC. The VGSC-expressing AL cells generated action potentials in response to depolarization under the current clamp configuration. These results clearly indicate that functional neurons expressing fast inactivating and TTXsensitive VGSC which generate action potentials exist in the AL of the chick. These lines of cellular evidence clearly indicate that functional neurons exist in ALs and further support the proposal that the chick ALs function as the sensory organ of equilibrium.

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“…It appears to be similarly (or slightly better) developed to that in present−day swifts (birds that rarely walk), although the culmination of the cord swelling is longer by one vertebra. It is much weaker than its counterpart in ostrichs and even pigeons (see Necker 2006, fig. 12; for a great set of photographs, consult Jelgersma 1951).…”

Section: Synsacral Canal and Its Anticipated Contentsmentioning

confidence: 95%

“…The fossa houses an enigmatic ovoid glial structure called the glyco− gen body (Jelgersma 1951;Breazile and Kuenzel 1993;Butler and Hodos 2005;Kai− ser 2007; see also Giffin 1990). The position of the lumbosacral intumescence and glycogen body can be easily located, for the corresponding part of the synsacral canal is enlarged (Necker 2006). This enlargement is quite conspicuous in fossil penguins (Fig.…”

Section: Synsacral Canal and Its Anticipated Contentsmentioning

confidence: 99%

“…These canals open above the lateral accessory lobes of the spinal cord which are presumably stimulated mechanically by movement of the fluid (for a review, see Necker 2006). The system is also present in the extant penguins, although Necker (2006) wall of the synsacral canal were shallow (like in cormorants and swifts; see Necker 2006, fig. 12).…”

Section: Synsacral Canal and Its Anticipated Contentsmentioning

confidence: 99%

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Synsacra of the Eocene Antarctic penguins: new data on spinal maturation and an insight into their role in the control of walking

Jadwiszczak

2014

Polish Polar Research

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Abstract:The synsacrum is an important element of the axial skeleton in birds, both volant and flightless. Little is known about the maturation of this complex bone in penguins. In this work, the supposedly ontogenetically youngest known synsacrum of early penguins was described. The analysis of this specimen, collected within the Eocene La Meseta Formation of Seymour (Marambio) Island, Antarctic Peninsula, revealed that this bird had attained at least the fledging stage of growth. Studies of three mature synsacra recovered from the same formation focused on the synsacral canals and, using indirect reasoning, their contents. These analyses revealed that the lumbosacral intumescence of the spinal cord and its exten− sions, the transverse canals, had been developed roughly like those in extant penguins (and also swifts and cormorants). The neural spine extensions (a non−nervous tissue) tracing the transverse grooves of the dorsal wall of the synsacral canal are currently considered as in− volved in the control of walking. The presented data suggest that such a sense organ gained its current penguin configuration by the late Eocene.

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Specializations in the lumbosacral vertebral canal and spinal cord of birds: evidence of a function as a sense organ which is involved in the control of walking

Cited by 51 publications

References 31 publications

Descrição anatômica de esqueletos de papagaios do gênero Amazona através da utilização de radiografias

Descrição anatômica de esqueletos de papagaios do gênero Amazona através da utilização de radiografias

Chick spinal accessory lobes contain functional neurons expressing voltagegated sodium channels generating action potentials

Synsacra of the Eocene Antarctic penguins: new data on spinal maturation and an insight into their role in the control of walking

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