Abstract
The projection pattern of the neurons of the paragriseal Hofmann nuclei was mapped in the chicken embryo using the lipophilic tracer DiI. This report focuses on the pattern of projection from the Hofmann nuclei major observed 1–4 days prior to hatching, at which time the projection appears to be substantially developed. (1) Each neuron extends a commissural axon through the ventral gray matter and across the midline in the ventral commissure. The axons originating from a single Hofmann nucleus cross within a stretch of the cord equivalent to about one spinal segment. There is a small overlap of the axon populations originating from adjacent Hofmann nuclei. After reaching the contralateral ventral columns the individual axons bifurcate and extend rostrally and caudally up to 5 spinal segments in each direction. The rostral and caudal trajectories differ; the rostral axons shift progressively more laterally while the caudal axons tend not to deviate from their initial course. (2) Throughout their longitudinal course the axons give rise to terminal collaterals that are concentrated in lamina 8. Rostrally and caudally the terminals decrease in density and become increasingly scattered. (3) Hofmann neurons are multipolar with 4–5 laterally directed primary dendrites whose arbors are restricted to the Hofmann nucleus major within which the neurons reside. (4) Hofmann neurons receive afferent terminals from a longitudinal column of commissural interneurons located contralaterally in close approximation to the central canal. Each Hofmann nucleus major is innervated by a rostrocaudally restricted subset of these presynaptic neurons. The axon trajectories of the presynaptic neurons are similar to those of the Hofmann neurons. (5) Paragriseal neurons that are not located within Hofmann nuclei major are also commissural intersegmental interneurons and tend to be clustered segmentally. The segmentation is clearest for the Hofmann nuclei minor, which are clusters of neurons iterated along the ventrolateral margin of the thoracic spinal cord but not organized in protruding lobes.
Similar content being viewed by others
References
Anderson FD, Meadows I, Chambers MM (1964) The nucleus marginalis of the mammalian spinal cord; observations on the spinal cord of cat and man. J Comp Neurol 123: 97–100
Bizzi E, Mussa-Ivaldi F, Giszter SF (1991) Computations underlying the execution of movement: a biological perspective. Science 253:287–291
Buchanan JT (1982) Identification of interneurons with contralateral caudal axons in the lamprey spinal cord: synaptic interactions and morphology. J Neurophysiol 47:961–975
DeGennaro LD, Benzo CA (1976) Ultralstructural characterization of the accessory lobes of Lachi (Hofman's nuclei) in the nerve cord of the chick. I. Axoglial synapses. J Exp Zool 198:97–107
Dubey PN, Kadasne DK, Gosavi VS (1968) The influence of the peripheral field on the morphogenesis of Hofmann's nucleus major of the chick spinal cord. J Anat 102:407–414
Duncan D (1953) On the incidence and locations of nerve cells in the spinal white matter of two species of primates, man and the cynomolgus monkey. J Comp Neurol 99:103–115
Forssberg H, Grillner S, Sjöström A (1974) Tactile placing reactions in chronic spinal kittens. Acta Physiol Scand 92:114–120
Forssberg H, Grillner S, Rossignol S (1975) Phase dependent reflex reversal during walking in chronic spinal cats. Brain Res 85:103–107
Fukson OI, Berkenblit MB, Feldman AG (1980) The spinal frog takes into account the scheme of its body during the wiping reflex. Science 209:1261–1263
Godement P, Vanselow J, Thanos S, Bonhoeffer F (1987) A study in developing visual systems with a new method of staining neurons and their processes in fixed tissue. Development 10: 697–713
Gottschaldt KM, Frühstorfer H, Schmidt W, Kraft I (1982) I. Thermosensitivity and its possible fine structural basis in mechanoreceptors in the beak skin of geese. J Comp Neurol 205:219–245
Grillner, S (1981) Control of locomotion in bipeds, tetrapods, and fish. In: Brooks VB (ed) Handbook of physiology, section 1. The nervous system, vol 2. Motor control. American Physiological Society, Bethesda, pp 1179–1236
Grillner S, McClellan A, Sigvardt S (1982) Mechanosensitive neurons in the spinal cord of the lamprey. Brain Res 217:380–386
Grillner S, Williams T, Lagerback PA (1984) The edge cell, a possible intraspinal mechanoreceptor. Science 223:500–503
Harper CE, Roberts A (1993) Spinal cord neuron classes in embryos of the smooth newt Triturus vulgaris: a horseradish peroxidase and immunocytochemical study. Philos Trans R Soc Lond Biol 340:141–160
Harrison PJ, Jankowska E, Zytnicki D (1986) Lamina VIII interneurones interposed in crossed reflex pathways in the cat. J Physiol (Lond) 371:147–166
Honig MG, Hume R (1986) Fluorescent carbocyanine dyes allow living neurons of identified origin to be studied in long term cultures. J Cell Biol 103:171–187
Huber, JF (1936) Nerve roots and nuclear groups in the spinal cord of the pigeon. J Comp Neurol 65:43–91
Jankowska E, Noga BR (1990) Contralaterally projecting lamina VIII interneurons in middle lumbar segments in the cat. Brain Res 535:327–330
Kuwada JL (1986) Cell recognition by neuronal growth cones in a simple vertebrate embryo. Science 233:740–746
Lim TM, Jaques KF, Stern CD, Keynes RJ (1991) An evaluation of myelomeres and segmentation of the chick embryo spinal cord. Development 113:227–238
Martin, AH (1979) A cytoarchitectonic scheme for the spinal cord of the domestic fowl, Gallus gallus domesticus: lumbar region. Acta Morphol Neurol Scand 17:105–117
Mortin LI, Keifer J, Stein PSG (1985) Three forms of the scratch reflex in the spinal turtle: movement analysis. J Neurophysiol 53:1501–1516
Necker R, Rautenberg W (1975) Effect of spinal deafferentation on temperature regulation and spinal thermosensitivity in pigeons. Pflügers Arch 360:287–299
Nornes HO, Hart H, Carry M (1980) Development of ascending and descending fibers in embryonic spinal cord of chick: I. Role of position information. J Comp Neurol 192:119–132
O'Donovan M, Ho S, Yee W (1994) Calcium imaging of rhythmic network activity in the developing spinal cord of the chick embryo. J Neurosci 14:6354–6369
Ohta Y, Dubuc R, Grillner S (1991) A new population of neurons with crossed axons in the lamprey spinal cord. Brain Res 564:143–148
Pearson KG, Duysens J (1976) Neural control of locomotion. Herman RM, Grillner S, Stein P, Stuart D (eds). Plenum Press, New York
Rovainen CM (1979) Neurobiology of lampreys. Physiol Rev 59:1007–1077
Schroeder DM, Richardson SC (1985) Is the intimate relationship between ligaments and marginal specialized cells in the snake's spinal cord indicative of a CNS mechanoreceptor? Brain Res 328:145–149
Schroeder DM, Murray RG (1987) Specialization within the lumbosacral spinal cord of the pigeon. J Morphol 194:41–53
Sugiuchi Y, Kakei S, Shinoda Y (1992) Spinal commissural neurons mediating vestibular input to neck motoneurons in the cat upper cervical spinal cord. Neurosci Lett 145:221–224
Viana Di Frisco G, Wallén P, Grillner S (1990) Synaptic effects of intraspinal stretch receptor neurons mediating movement-related feedback during locomotion. Brain Res 530:161–166
Østnes JE, Bech C (1992) Thermosensitivity of different parts of the spinal cord of the pigeon (Columbia livia). J Exp Biol 162:185–196
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Eide, A.L. The axonal projections of the Hofmann nuclei in the spinal cord of the late stage chicken embryo. Anat Embryol 193, 543–557 (1996). https://doi.org/10.1007/BF00187926
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00187926