caa a22 4500 477095232 CHVBK 20180405111525.0 cr unu---uuuuu 170330e19960601xx s 000 0 eng 10.1007/BF00187926 doi (NATIONALLICENCE)springer-10.1007/BF00187926 Eide Anne Department of Physiology, Institute of Basic Medical Sciences, University of Oslo, Blindern, Box 1105, N-0317, Oslo, Norway aut The axonal projections of the Hofmann nuclei in the spinal cord of the late stage chicken embryo [Elektronische Daten] [Anne Eide] 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. Springer-Verlag, 1996 Commissural nationallicence Paragriseal nationallicence DiI neuronal tracing nationallicence Intersegmental connections nationallicence Accessory lobes of Lachi nationallicence Anatomy and Embryology Springer-Verlag 193/6(1996-06-01), 543-557 0340-2061 193:6<543 1996 193 429 https://doi.org/10.1007/BF00187926 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00187926 text/html Onlinezugriff via DOI NATIONALLICENCE 100 1- Eide Anne Department of Physiology, Institute of Basic Medical Sciences, University of Oslo, Blindern, Box 1105, N-0317, Oslo, Norway aut NATIONALLICENCE 773 0- Anatomy and Embryology Springer-Verlag 193/6(1996-06-01), 543-557 0340-2061 193:6<543 1996 193 429 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer