Efferent connections of area 20 in the cat: HRP-WGA and autoradiographic studies

Abstract

Following injections of horseradish peroxidase-wheat germ agglutinin conjugate (HRP-WGA) and tritiated leucine into area 20 of the cat, terminal labeling was observed in visual areas 19, 21, the splenial visual area, the lateral suprasylvian area as well as in premotor, association and limbic related cerebral cortical regions. Labeled terminals in the subcortex were distributed in the caudate nucleus, the claustrum, the putamen, the anterior ventral nucleus, the intralaminar nuclei, the caudal division of the intermediate lateral nucleus, the lateralis posterior-pulvinar complex, the parvocellular C laminae of the dorsal lateral geniculate nucleus and the ventral lateral geniculate nucleus. In HRP-WGA preparations, retrogradely labeled somata were observed in these regions with the exception of certain subcortical structures. The projections are discussed with respect to the possible role area 20 plays in the cortical control of pupillary constriction.

The Structure and Connections of the Claustrum

“…Afferents from the claustrum to the cortical pupillo-constrictor area (posterior suprasylvian gyrus, area 20) of the cat were demonstrated by S. Kuchiiwa et al (1984Kuchiiwa et al ( , 1985. Neurons projecting to this area were observed ipsilaterally in the caudal half of the CL.…”

Widespread Distribution of Visual Responsiveness in Frontal, Prefrontal, and Prelimbic Cortical Areas of the Cat: An Electrophysiologic Investigation

“…Additional sources of visual/visuomotor input have been reported for VM and VA. The ventral medial nucleus and ventromedial portions of VA receive projections from the intermediate and deep layers of the superior colliculus (Nakano et al, 1985), and VA receives projections from suprasylvian visual areas (Updyke, 1981;Kuchiiwa et al, 1985;Zhang, 1993). The principal cortical target of VL is area 4␥, with lesser input reported to areas 4␦, 6a␣, and 6a␥ (Strick, 1973;Yumiya and Ghez, 1984;Morá n and Reinoso-Suá rez, 1988).…”

“…With the possible exception of area 19 (Battaglini et al, 1980), visual areas 17, 18, and 19 do not project to motor or prefrontal areas. Areas anteromedial lateral suprasylvian visual area (AMLS), anterolateral lateral suprasylvian visual area (ALLS), posterior lateral lateral suprasylvian visual area (PLLS), 20b, and ectosylvian visual area (EVA) are reported to project only very sparsely to area 6a␤ and adjacent prefrontal cortex (Babb et al, 1984;Cavada and Reinoso-Suá rez, 1985;Kuchiiwa et al, 1985;Olson and Jeffers, 1987). Although there is ample evidence that many cortical visual areas in cat may influence cortical motor areas by means of indirect corticopontine (Albus et al, 1981;Cohen et al, 1981;Brodal, 1983, 1989) or corticostriatal projections (Royce, 1982;Norita et al, 1991;Updyke, 1993), corticocortical visual pathways directed at motor and prefrontal areas appear to be funneled through a very limited set of intermediary cortical areas, which include area 7, area 5, and the insular visual area.…”

The pupillary light reflex in normal and innate microstrabismic cats, II: Retinal and cortical input to the nucleus praetectalis olivaris

“…Although a cortical input to the NPO could be identified in monkeys using degeneration methods and autoradiography (Fuse, 1936;Dineen & Hendrickson, 1983), and rabbit (Giolli et al, 1974), anatomical studies of corticofugal projections revealed no input from cortical areas 17,18,19,20,21,7, and Clare-Bishop area to the NPO in the cat (Kawamura et al, 1974;Updyke, 1977). Anatomical studies especially related to the pupilloconstrictor areas yielded inconsistent results: while Kuchiiwa et al (1984Kuchiiwa et al ( , 1985 could not identify any direct projection of these areas to the pretectum and especially the NPO, the data of Barris (1936) show some degenerated fibers within the region of the NPO.…”