Mo. Lopezfigueroa et al., PROJECTIONS FROM THE VISUAL AREAS TO THE NEOSTRIATUM IN RATS - A REEXAMINATION, Acta Neurobiologiae Experimentalis, 55(3), 1995, pp. 165-175
Neostriatal afferents from the primary visual cortex in rats were stud
ied using dextran-biotin, biocytin, and Fluoro-Gold. The area V1 was f
ound to project only to a dorsomedial, longitudinal region of neostria
tum (NS), bordering on the lateral ventricle and subcortical white mat
ter. The preterminal fibres in the NS form fluffs which increase in nu
mber and density in the cases with larger injections. This target regi
on is poorly stained for calbindin and yet belongs to the matrix compa
rtment. The secondary visual areas also project to the dorsomedial NS
region but they also innervate the deeper tissue in the same general r
egion. Iontophoresis of Fluoro-Gold into the dorsomedial NS labelled s
ome pyramidal neurones in the fifth layer of the primary visual cortex
. The cortical areas that surround the visual cortical complex project
to other regions of the NS: the somatosensory cortex to a dorsolatera
l longitudinal region and the auditory area to the medial half of the
caudalmost portion of NS. Thus, major sensory cortical divisions proje
ct to non-overlapping NS regions. Since NS in monkeys and cats does no
t receive afferents from the primary visual cortex and in a number of
other species does, we conclude that visual systems in different mamma
ls differ with respect to their projections to NS.