Thomas Graham Brown (1882–1965), Anders Lundberg (1920–), and the neural control of stepping

Stuart, Douglas G.; Hultborn, Hans

doi:10.1016/j.brainresrev.2008.06.001

Cited by 103 publications

(75 citation statements)

References 98 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This might seem surprising, as the defect in ascending spinal projections likely blocks the transmission of proprioceptive information to the brain. However, a large body of work on intrinsic spinal cord locomotor circuits demonstrates that for many reflex responses somatosensory information is integrated into locomotor programs at the level of spinal circuits with little or no involvement of supraspinal mechanisms (31,32). Moreover, the sparing of sensory axons in the head in Cdx1-Cre;Fz3 CKO/− mice implies that vestibular, whisker, and visual inputs should be integrated normally to modulate descending motor commands to the spinal cord.…”

Section: Discussionmentioning

confidence: 99%

Frizzled3 is required for the development of multiple axon tracts in the mouse central nervous system

Hua¹,

Jeon

Caterina

et al. 2014

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

View full text Add to dashboard Cite

Targeted mutation of the Frizzled3 (Fz3) gene in mice has been shown to disrupt the growth and guidance of a subset of peripheral and central axons. Here we used conditional deletion of Fz3 to explore the forebrain territories in which Fz3 action is required for the development of the anterior commissure and the corticothalamic, corticospinal, and thalamocortical tracts. Experiments with regionspecific deletion of Fz3 using a variety of Cre lines show that proper routing of corticothalamic and thalamocortical axons in the internal capsule requires Fz3 expression in the ventral telencephalon. The pattern of defects among forebrain axon tracts that are induced by conditional deletion of Fz3 conforms closely to the pattern previously observed with analogous conditional deletion of Celsr3, implying a close mechanistic link between Fz3 and Celsr3 in axon guidance. We further found that several central nervous system axon tracts require Fz3 function as early as embryonic day 11.5, and that Fz3 is required for pathfinding by dopaminergic and serotonergic axons in the brain and by a subset of optic tract axons. In addition, conditional deletion of Fz3 in all tissues caudal to the neck eliminates the spinothalamic tract and the transmission of somatosensory information from the spinal cord to the brain, as determined by neuroanatomic tracing and behavioral testing.planar cell polarity | Cre/loxP C omplexity within the mammalian nervous system can be roughly divided into two categories: cell type identity and morphology/connectivity. On its largest scale, the second category is exemplified by the many distinct patterns of long-range axonal trajectories within the adult CNS. The guidance mechanisms responsible for these axonal trajectories have been an object of longstanding interest to neurobiologists, and, over the past 20 y, a wide variety of attractive and repulsive axon guidance systems have been identified (1). For a few well-defined axon growth and guidance decisions-such as dorsal vs. ventral growth of limb motor axons and midline crossing of retinal ganglion cell (RGC) and spinal sensory axons-the roles of several guidance systems, including Slit/Robo, Ephrin/Eph, and Semaphorin/Plexin, have been intensively investigated (2, 3).One recently discovered axon growth and guidance system uses some of the same molecular components that were identified in the context of epithelial polarity determination, a process referred to as tissue polarity or planar cell polarity (PCP). As first defined in Drosophila, PCP controls polarity within the plane of the epithelium and is mediated by a small number of integral membrane or membrane-associated proteins (4). Within the responsive epithelium, several PCP proteins are localized asymmetrically within each cell in a pattern that matches the large-scale vectorial asymmetry of the epithelium. In mice, two integral membrane PCP proteins, Frizzled3 (Fz3) and Celsr3, control a nearly identical set of axon growth and guidance processes, with loss-of-function mutations in either gene pro...

show abstract

Section: Discussionmentioning

confidence: 99%

Frizzled3 is required for the development of multiple axon tracts in the mouse central nervous system

Hua¹,

Jeon

Caterina

et al. 2014

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

View full text Add to dashboard Cite

show abstract

“…For example, although it has been studied intensively for more than a century [70,71], there is still no agreement on the cellular basis for spinal-generated locomotion [72][73][74]. Thus, in order to understand how motor behaviours evolved, one would need to study nervous systems with clear species differences that are accessible to analysis.…”

Section: Motor System Evolutionmentioning

confidence: 99%

Neural mechanisms underlying the evolvability of behaviour

Katz

2011

Phil. Trans. R. Soc. B

View full text Add to dashboard Cite

The complexity of nervous systems alters the evolvability of behaviour. Complex nervous systems are phylogenetically constrained; nevertheless particular species-specific behaviours have repeatedly evolved, suggesting a predisposition towards those behaviours. Independently evolved behaviours in animals that share a common neural architecture are generally produced by homologous neural structures, homologous neural pathways and even in the case of some invertebrates, homologous identified neurons. Such parallel evolution has been documented in the chromatic sensitivity of visual systems, motor behaviours and complex social behaviours such as pair-bonding. The appearance of homoplasious behaviours produced by homologous neural substrates suggests that there might be features of these nervous systems that favoured the repeated evolution of particular behaviours. Neuromodulation may be one such feature because it allows anatomically defined neural circuitry to be re-purposed. The developmental, genetic and physiological mechanisms that contribute to nervous system complexity may also bias the evolution of behaviour, thereby affecting the evolvability of species-specific behaviour.

show abstract

“…Mammalian locomotion has traditionally been analyzed in cats by kinematic and electromyographic (EMG) evaluation of the walking step cycle, with a focus on the hindlimb (1,2,4,9). These studies have shown that individual extensor and flexor muscles controlling the hip, knee, and ankle joints exhibit distinct and stereotypic onset and offset timing, as well as a pronounced alternation in flexor-extensor phasing that accompanies the transition from stance to swing, or swing to stance (1,2,4).…”

mentioning

confidence: 99%

Degradation of mouse locomotor pattern in the absence of proprioceptive sensory feedback

Akay

Tourtellotte

Arber

et al. 2014

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

239

268

View full text Add to dashboard Cite

Significance Terrestrial locomotion is thought to be generated by the actions of a circuit of interconnected interneurons (central pattern generator) in the spinal cord that drive the patterned activity of pools of motor neurons, causing sequential contraction of dozens of leg muscles. Sensory feedback exerts a strong modulatory influence on this pattern; nevertheless, it remains unclear whether sensory feedback also plays a role in the generation of the normal locomotor pattern. Through the use of a combination of electrophysiology, behavior, and mouse genetics, we provide evidence that the absence of proprioceptive sensory feedback degrades locomotor pattern, indicating that proprioceptive feedback is required for the construction of locomotor pattern.

show abstract

Thomas Graham Brown (1882–1965), Anders Lundberg (1920–), and the neural control of stepping

Cited by 103 publications

References 98 publications

Frizzled3 is required for the development of multiple axon tracts in the mouse central nervous system

Frizzled3 is required for the development of multiple axon tracts in the mouse central nervous system

Neural mechanisms underlying the evolvability of behaviour

Degradation of mouse locomotor pattern in the absence of proprioceptive sensory feedback

Contact Info

Product

Resources

About