Stimulation of the brainstem reticular formation evokes locomotor activity in embryonic chicken (in ovo)

Valenzuela, Jerilee; Hasan, Sohail; Steeves, John D.

doi:10.1016/0165-3806(90)90158-u

Cited by 26 publications

(11 citation statements)

References 12 publications

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“…If this were the case, however, it is unlikely that the locomotor abilities would have been so equivalent (1). Further evidence comes from our previous demonstration in late embryos and hatchling chicks that direct focal stimulation of brainstem-spinal neurons, within the gigantocellular reticular formation (an identified brainstem locomotor region), elicited locomotor activity only in an animal transected prior to E13 (9,10,18 Antisera against GalC, the major oligodendrocyte sphingolipid (19), have been shown to demyelinate CNS tissue in vitro (20,21) and optic nerve (22,23) and spinal cord (24) We are uncertain whether the oligodendrocyte cell bodies survive our dysmyelination procedure. In vitro, the proposed mechanism of anti-GalC-induced demyelination involves microtubule disassembly and retraction of oligodendrocyte processes mediated by an influx ofextracellular calcium (21).…”

Section: Discussionmentioning

confidence: 99%

Suppression of the onset of myelination extends the permissive period for the functional repair of embryonic spinal cord.

Keirstead

Hasan

Muir

et al. 1992

Proc. Natl. Acad. Sci. U.S.A.

146

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In an embryonic chicken, traneto of the thoracic spinal cord prior to embryonic day (E) The anatomical development and functional organization of avian descending brainstem-spinal pathways concerned with locomotion is similar to that of other vertebrates, including mammals (1,(5)(6)(7)(8)(9)(10). If the thoracic spinal cord of an embryonic chicken is transected prior to day 13 (E13) of the 21-day developmental period, the animal will subsequently effect complete neuroanatomical and physiological repair resulting in total functional recovery (8-10). Most importantly, regeneration of previously severed axonal fibers contributes to this repair process (10

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Section: Discussionmentioning

confidence: 99%

Suppression of the onset of myelination extends the permissive period for the functional repair of embryonic spinal cord.

Keirstead

Hasan

Muir

et al. 1992

Proc. Natl. Acad. Sci. U.S.A.

146

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“…sprouting, axon elongation) suggests that trophic factor replacement therapy may, in the future, prove to be part of an effective, multifaceted therapy for SCI. Many of the upper motor neuron populations involved in locomotor control, such as the vestibular, raphe and red nuclei as well as the reticular formation lie within the brainstem (Valenzuela et al, 1990). Presently, however, little is known about the trophic requirements of these bulbospinal neuron populations partly due to a lack of specific molecular markers.…”

Section: Methodsmentioning

confidence: 99%

IGF‐1 and BDNF promote chick bulbospinal neurite outgrowth in vitro

Salie

Steeves

2005

Intl J of Devlp Neuroscience

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Injured neurons in the CNS do not experience significant functional regeneration and so spinal cord insult often results in permanently compromised locomotor ability. The capability of a severed axon to re-grow is thought to depend on numerous factors, one of which is the decreased availability of neurotrophic factors. Application of trophic factors to axotomized neurons has been shown to enhance survival and neurite outgrowth. Although brainstem-spinal connections play a pivotal role in motor dysfunction after spinal cord injury, relatively little is known about the trophic sensitivity of these populations. This study explores the response of bulbospinal populations to various trophic factors. Several growth factors were initially examined for potential trophic effects on the projection neurons of the brainstem. Brain derived neurotrophic factor (BDNF) and insulin-like growth factor (IGF-1) significantly enhance mean process length in both the vestibulospinal neurons and spinal projection neurons from the raphe nuclei. Nerve growth factor (NGF), neurotrophin-4 (NT-4) and glial derived neurotrophic factor (GDNF) did not effect process outgrowth in vestibulospinal neurons. At the developmental stages used in this study, it was determined that receptors for BDNF and IGF-1 were present both on bulbospinal neurons and on surrounding cells with a non-neuronal morphology.

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“…1A) (Bottjer et al, 2000). The medial pontine reticular formation contains premotor neurons that contribute to neck and locomotive movements in other avian species (Steeves et al, 1987;Valenzuela et al, 1990;Dubbeldam, 1998;Wild and Krützfeldt, 2012); peck, preening, and hop-related activity may in part reflect these projections to premotor centers. Moreover, previous studies have found evidence of induced ZENK activity in AId specifically during hopping behavior (Feenders et al, 2008).…”

Section: Multi-modal Integration Provides Behavioral Context For Volumentioning

confidence: 99%

Multi-dimensional tuning in motor cortical neurons during active behavior

Yuan

Bottjer

2020

Preprint

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A region within songbird cortex, AId (dorsal intermediate arcopallium), is functionally analogous to motor cortex in mammals and has been implicated in vocal learning during development. AId thus serves as a powerful model for investigating motor cortical contributions to developmental skill learning. We made extracellular recordings in AId of freely behaving juvenile zebra finches and evaluated neural activity during diverse motor behaviors throughout entire recording sessions, including song production as well as hopping, pecking, preening, fluffups, beak interactions with cage objects, scratching, and stretching. A large population of single neurons showed significant modulation of activity during singing relative to quiescence. In addition, AId neurons demonstrated heterogeneous response patterns that were evoked during multiple movements, with single neurons often demonstrating excitation during one movement type and suppression during another. Lesions of AId do not disrupt vocal motor output or impair generic movements, suggesting that the responses observed during active behavior do not reflect direct motor drive. Consistent with this idea, we found that some AId neurons showed differential activity during pecking movements depending on the context in which pecks occurred, suggesting that AId circuitry encodes diverse inputs beyond generic motor parameters.Moreover, we found evidence of neurons that did not respond during discrete movements but were nonetheless modulated during active behavioral states compared to quiescence. Taken together, our results support the idea that AId neurons are involved in sensorimotor integration of external sensory inputs and/or internal feedback cues to help modulate goal-directed behaviors. SIGNIFICANCE STATEMENTMotor cortex across taxa receives highly integrated, multi-modal information and has been implicated in both execution and acquisition of complex motor skills, yet studies of motor cortex typically employ restricted behavioral paradigms that target select movement parameters, preventing wider assessment of the diverse sensorimotor factors that can affect motor cortical activity. Recording in AId of freely behaving juvenile songbirds that are actively engaged in sensorimotor learning offers unique advantages for elucidating the functional role of motor cortical neurons. The results demonstrate that a diverse array of factors modulate motor cortical activity and lay important groundwork for future investigations of how multi-modal information is integrated in motor cortical regions to contribute to learning and execution of complex motor skills.3

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Stimulation of the brainstem reticular formation evokes locomotor activity in embryonic chicken (in ovo)

Cited by 26 publications

References 12 publications

Suppression of the onset of myelination extends the permissive period for the functional repair of embryonic spinal cord.

Suppression of the onset of myelination extends the permissive period for the functional repair of embryonic spinal cord.

IGF‐1 and BDNF promote chick bulbospinal neurite outgrowth in vitro

Multi-dimensional tuning in motor cortical neurons during active behavior

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