The axon arbourisation of nuclei isthmi neurons in the optic tectum of the chick and pigeon. A Golgi and anterograde tracer-study

Tömböl, T; Eyre, Mark D.; Alpár, Alán; Németh, Á.

doi:10.1007/s00429-004-0450-x

Cited by 8 publications

(1 citation statement)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A terminal varicosity in layer 10 described by Ramón y Cajal (1911) in sparrows was not seen in the current study. Two major variations of Ipc brush-like endings were observed in the current tracing studies and may correspond to the long and short axonal arborizations identified by Tömböl et al (1995Tömböl et al ( , 20051998), although our observation does not support their previous suggestion that short and long endings, respectively, arise from Ipc and Imc. The light, diffuse projection from Ipc on the deep tectal layers 11-13 was first identified in our PHA-L tracing studies and further confirmed with intracellular filling of individual Ipc neurons.…”

Section: Columnar Axonal Terminations Of Ipc and Slu Neuronscontrasting

confidence: 61%

Columnar projections from the cholinergic nucleus isthmi to the optic tectum in chicks (Gallus gallus): A possible substrate for synchronizing tectal channels

et al. 2005

View full text Add to dashboard Cite

The cholinergic division of the avian nucleus isthmi, the homolog of the mammalian nucleus parabigeminalis, is composed of the pars parvocellularis (Ipc) and pars semilunaris (SLu). Ipc and SLu were studied with in vivo and in vitro tracing and intracellular filling methods. 1) Both nuclei have reciprocal homotopic connections with the ipsilateral optic tectum. The SLu connection is more diffuse than that of Ipc. 2) Tectal inputs to Ipc and SLu are Brn3a-immunoreactive neurons in the inner sublayer of layer 10. Tectal neurons projecting on Ipc possess "shepherd's crook" axons and radial dendritic fields in layers 2-13. 3) Neurons in the mid-portion of Ipc possess a columnar spiny dendritic field. SLu neurons have a large, nonoriented spiny dendritic field. 4) Ipc terminals form a cylindrical brush-like arborization (35-50 microm wide) in layers 2-10, with extremely dense boutons in layers 3-6, and a diffuse arborization in layers 11-13. SLu neurons terminate in a wider column (120-180 microm wide) lacking the dust-like boutonal features of Ipc and extend in layers 4c-13 with dense arborizations in layers 4c, 6, and 9-13. 5) Ipc and SLu contain specialized fast potassium ion channels. We propose that dense arborizations of Ipc axons may be directed to the distal dendritic bottlebrushes of motion detecting tectal ganglion cells (TGCs). They may provide synchronous activation of a group of adjacent bottlebrushes of different TGCs of the same type via their intralaminar processes, and cross channel activation of different types of TGCs within the same column of visual space.

show abstract

Section: Columnar Axonal Terminations Of Ipc and Slu Neuronscontrasting

confidence: 61%

Columnar projections from the cholinergic nucleus isthmi to the optic tectum in chicks (Gallus gallus): A possible substrate for synchronizing tectal channels

et al. 2005

View full text Add to dashboard Cite

show abstract

Combining visual information from the two eyes: The relationship between isthmotectal cells that project to ipsilateral and to contralateral optic tectum using fluorescent retrograde labels in the frog, Rana pipiens

Dudkin

Sheffield

Gruberg

2007

J of Comparative Neurology

View full text Add to dashboard Cite

The frog nucleus isthmi (homolog of the mammalian parabigeminal nucleus) is a visually responsive tegmental structure that is reciprocally connected with the ipsilateral optic tectum; cells in nucleus isthmi also project to the contralateral optic tectum. We investigated the location of the isthmotectal cells that project ipsilaterally and contralaterally using three retrograde fluorescent label solutions: Alexa Fluor 488 10,000 mw dextran conjugate; Rhodamine B isothiocyanate; and Nuclear Yellow. Dye solutions were pressure-injected into separate sites in the superficial optic tectum. Following a 6-day survival, brains were fixed, sectioned, and then photographed. Injection of the different labels at separate, discrete locations in the optic tectum result in retrograde filling of singly labeled clusters of cells in both the ipsilateral and contralateral nucleus isthmi. Generally, ipsilaterally projecting cells are dorsal to the contralaterally projecting cells, but there is a slight overlap between the two sets of cells. Nonetheless, when different retrograde labels are injected into opposite tecta, there is no indication that individual cells project to both tecta. The set of cells that project to the ipsilateral tectum and the set of cells that project to the contralateral tectum form a visuotopic map in a roughly vertical, transverse slab. Our results suggest that nucleus isthmi can be separated into two regions with cells in the dorsolateral portion projecting primarily to the ipsilateral optic tectum and cells in the ventrolateral nucleus isthmi projecting primarily to the contralateral optic tectum.

show abstract

Topographical organisation of projections from the nucleus isthmi magnocellularis to the optic tectum of the chick brain

et al. 2005

Self Cite

View full text Add to dashboard Cite

The anatomical connection of the magnocellular isthmic nucleus with the optic tectum was investigated with the axonal tracer biotinylated dextran amine. Following iontophoretic injection of this tracer into different areas of the chick optic tectum, neurones of both magno- and parvocellular isthmic nuclei were labelled together in a topographical arrangement. The number of labelled neurones in the parvocellular nucleus was generally higher than in magnocellular. Using different locations of the tracer injections, systematic shifts in the location of the labelled neurones were detected. The labelled axons were seen to course along the shortest possible distance between the injection site and the cells of origin, i.e., the ventral part of the tectum received projections from neurones located ventrally in the isthmic nuclei, the dorsal tectum from neurones in the dorsal part, and the lateral extension of the tectum from neurones lying midway along the nuclei. This parallel and topographic projection of the two nuclei was primarily observed in sagittal sections. After tracer injections into the magnocellular nucleus, the terminal arbours were seen to extend from the deep layers (11-12) to layer 2 of the tectum. The projections observed appeared to be topographically organised, and furthermore appeared to be parallel with and complimentary to previously described projections of the parvocellular isthmic nucleus.

show abstract

The axon arbourisation of nuclei isthmi neurons in the optic tectum of the chick and pigeon. A Golgi and anterograde tracer-study

Cited by 8 publications

References 27 publications

Columnar projections from the cholinergic nucleus isthmi to the optic tectum in chicks (Gallus gallus): A possible substrate for synchronizing tectal channels

Columnar projections from the cholinergic nucleus isthmi to the optic tectum in chicks (Gallus gallus): A possible substrate for synchronizing tectal channels

Combining visual information from the two eyes: The relationship between isthmotectal cells that project to ipsilateral and to contralateral optic tectum using fluorescent retrograde labels in the frog, Rana pipiens

Topographical organisation of projections from the nucleus isthmi magnocellularis to the optic tectum of the chick brain

Contact Info

Product

Resources

About