scholarly journals Commissural communication allows mouse intergeniculate leaflet and ventral lateral geniculate neurons to encode interocular differences in irradiance

2018 ◽  
Vol 596 (22) ◽  
pp. 5461-5481 ◽  
Author(s):  
A. Pienaar ◽  
L. Walmsley ◽  
E. Hayter ◽  
M. Howarth ◽  
T. M. Brown
Keyword(s):  
Lateral Geniculate ◽  
Intergeniculate Leaflet

Intergeniculate leaflet and suprachiasmatic nucleus organization and connections in the golden hamster

1992 ◽  
Vol 8 (3) ◽  
pp. 219-230 ◽  
Author(s):  
L.P. Morin ◽  
J. Blanchard ◽  
R.Y. Moore
Keyword(s):  
Substance P ◽  
Neuropeptide Y ◽  
Suprachiasmatic Nucleus ◽  
Optic Tract ◽  
Zona Incerta ◽  
Acid Decarboxylase ◽  
Lateral Geniculate ◽  
Caudal Portion ◽  
Medial Geniculate ◽  
Intergeniculate Leaflet

AbstractThe intergeniculate leaflet (IGL) is a distinct subdivision of the lateral geniculate complex which receives retinal input and projects upon a circadian pacemaker, the suprachiasmatic nucleus (SCN). In the present study, we have analyzed the organization of the IGL and its connections in the hamster, a species commonly used in circadian rhythm studies. The location of the IGL is defined by the presence of retinal afferents demonstrated by anterograde transport of cholera toxin-HRP, neuropeptide Y-containing neurons and axons, cells retrogradely labeled from the regions of the SCN and contralateral IGL, and substance P-containing axons. It is a long nucleus extending the entire rostrocaudal axis of the geniculate. The most rostral IGL lies between the lateral dorsal thalamus, ventrolateral part, and the horizontal cerebral fissure. It then enlarges ventral to the rostral dorsal lateral geniculate, medial to the optic tract. The mid-portion of the leaflet is a thin lamina intercalated between the dorsal and ventral geniculate nuclei. The extended caudal portion of the nucleus lies lateral and ventral to the medial geniculate and is contiguous with the zona incerta and the lateral terminal nucleus. The IGL contains populations of neuropeptide Y (NPY+) and enkephalin (ENK+) neurons which project to the retinorecipient portion of the SCN. In addition to the immunoreactive perikarya, the IGL contains plexuses of NPY+, ENK +, substance P-, serotonin-, and glutamic acid decarboxylase-immunoreactive axons.Retrograde transport studies demonstrate that, in addition to the NPY+ neurons, there is a population of non-NPY+ neurons projecting upon the SCN. There is also a reciprocal projection upon the IGL from neurons in the SCN region, particularly the retrochiasmatic area. The hamster SCN differs from the rat in containing a distinct subdivision of substance P-immunoreactive neurons.

Retinal projections in the ground squirrel (Citellus tridecemlineatus)

1989 ◽  
Vol 3 (6) ◽  
pp. 537-549 ◽  
Author(s):  
Seema Agarwala ◽  
Heywood M. Petry ◽  
Jack G. May
Keyword(s):  
Horseradish Peroxidase ◽  
Suprachiasmatic Nucleus ◽  
Ground Squirrel ◽  
Mammalian Species ◽  
Optic Tract ◽  
Accessory Optic System ◽  
Anterograde Transport ◽  
Retinal Projections ◽  
Lateral Geniculate ◽  
Intergeniculate Leaflet

AbstractThe retinal projections of the thirteen-lined ground squirrel were determined by tracing anterograde transport of intravitreally injected horseradish peroxidase (HRP) or wheat-germ conjugated horseradish peroxidase (WGA-HRP). Label was seen in the suprachiasmatic nucleus and adjacent anterior hypothalamic area, the accessory optic system (the medial, dorsal, and lateral terminal nuclei), the dorsal and ventral lateral geniculate nuclei, the intergeniculate leaflet, the pretectal nuclei (the anterior, posterior, and olivary pretectal nuclei and the nucleus of optic tract), and the superior colliculus. Most of these structures were labeled bilaterally, with dense contralateral label and sparse ipsilateral label, a pattern typical for animals with laterally placed eyes. However, the suprachiasmatic nucleus and the nucleus of the optic tract received input only from the contralateral eye. In contrast to previous degeneration studies, the sensitive HRP tracers (in conjunction with cytochrome-oxidase reactivity) revealed an elaborate organization within the lateral geniculate nucleus (dorsal LGN, ventral LGN, and intergeniculate leaflet) that is consistent with existing organizational schemes for other mammalian species.

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