Retinal Developmental and Visual System Mutants
Prenatal Development of Retinal Projections to the Superior
Colliculus in the Cat
Here we characterize the sweeping reorganization of retinal connections
to the superior colliculus of fetal cats. This paper was published by R.
W. Williams and Leo Chalupa in The Journal of Neuroscience
2:604–622. This web edition includes revisions, annotations, and several
The distribution of retinal ganglion cells in the cat’s retina. Colors
are used to indicate cell packing density. The area centralis (dark blue
region) contains as many as 8,600 cells/mm2. Cell densities
are particularly high along the hroizontal axes from the temporal
periphery (right) to the nasal periphery (left). If you select the image
you may view an enlarged version with overlaid cell counts per 0.058 µm2
(multiply by 17.24 to obtain cell densities per mm2).
Binocular Interaction and Ganglion Cell Death
Interrupting binocular interactions early in development by removing one
eye results in an increase in numbers of retinal gangliion cell axons
originating from the spared eye. In this collaboration with Zaineb
Henderson, Leo Chalupa and I verified that numbers of ganglion cells are
increased and assessed how these surplus cells are distributed. This
paper was published in Neuroscience 12: 1139–1146 (1984).
Prenatal Development and Reorganization of the Cat’s Visual System
This review by Leo Chalupa and R. W. Williams summarizes work on visual
system development in cat carried out in Leo Chalupa’s laboratory from
about 1980 through 1984. It includes our only published account of the
development of retinal projections to the thalamus. Published in
Development of Visual Pathways in Mammals.
Target Recognition and Visual Maps in the Thalamus of Achiasmatic
First of a set of papers on the achiasmatic mutation in dogs. In these
remarkable achiasmatic mutants, all retinal ganglion cell axons have an
uncrossed projection. The anatomical and functional repercussions of
this decussation error are fascinating. This paper is our initial
analysis of the mutation and was published by Robert Williams, Dale
Hogan, and Preston Garraghty in Nature 367:637–639 (1993).
Analysis of the Retinas and Optic Nerves of Achiasmatic Belgian
In this study Dale Hogan and I test whether the retina or optic chiasm
is the likely site of mutant gene action in achiasmatic mutant dogs.
Retinas of mutants were examined to discover any associated changes in
retinal structure. Thre are some differences, but we still suspect that
the chiasm is the site of gene action. The paper was originally
published in 1995 in The Journal of Comparative Neurology
Asymmetric Connections, Duplicate Layers, and a Vertically Inverted
Map in the Primary Visual System
What happens when both eyes connect to only one side of the brain? This
paper by Dale Hogan, Preston Garraghty, and Robert Williams describes
the bizarre, but functional, consequences of having only half an optic
chiasm. Published in
The Journal of Neuroscience. This is an Adobe Acrobat pdf
Structure of Clonal and Polyclonal Cell Arrays in Chimeric Mouse
A paper by Rob Williams and Dan Goldowitz on clones of retinal cells in
aggregation chimeras. Published in Proceeding of the National Academy of
Lineage vs. Environment in Embryonic Retina
A controversial review published in Trends in Neuroscience in
1992. In this article Dan Goldowitz and I reanalyzed data on retinal
clones generated by David Turner and Constance Cepko. Based on several
Monte Carlo simulations and on our own studies of clones in retinas of
chimeric mice, we argued that lineage has a definite role in cell
determination in retina—that lineage restriction has to be considered a
probabilistic process rather than as an absolute switch. At the time,
the ideas outlined in this review were not received with enthusiasm
(read our critics: their letters are included). Now the main idea in
this article has been largely assimilated.
Clonal Architecture of the Mouse Retina
A review by Dan Goldowitz and colleagues on clones of retinal cells in
aggregation chimeras published in Progress in Brain Research
Extrinsic Modulation of Retinal Ganglion Cell Projections
A visually-stunning and technical complex paper with a simple
message—the expression of the tyrosinase enzyme in the pigment
epithelium is critical to axon navigation by retinal ganglion cells. Now
we would like to know how pigmentation, and the lack of pigmentation,
modulates ganglion cell differentiation and the growth of their axons.
Developmental Biology by Dennis S. Rice and colleagues. This
is an Adobe Acrobat pdf file.
The Human Retina has a Cone-Enriched Rim
I am probably the third person to have rediscovered that the rim of the
human retina is jam-packed with cones. This is also true of baboons,
talapoins, and some (but not all) macaque species (RW Williams,
unpublished). The functional significance of this cone-rich rim is still
in doubt, but my favorite hypothesis or speculation is that the cone rim
may be the visual system's equivalent of a rapid-response network.
Visual Neuroscience 6:403.
Mapping the Bst Mutation on Mouse Chr 16
A paper by Dennis S. Rice and colleagues on the belly spot and tail
mutation. Bst is an autosomal dominant mutation of an unknown gene that
is associated with variable optic nerve aplasia. This is a short gene
mapping study published in Mammalian Genome 6:546.