Journal of Neuroscience, Vol 1, 981-992, Copyright © 1981 by Society for Neuroscience
The visual claustrum of the cat. II. The visual field map
S LeVay and H Sherk
Physiological and anatomical methods were used to study the representation
of the visual field in the cat's dorsocaudal claustrum. In one set of
experiments, the visual receptive fields of claustral neurons were plotted
in multiple electrode penetrations. In another set of experiments, the
termination of the corticoclaustral pathway was examined
autoradiographically after the injection of [3H]proline at retinotopically
defined sites in the visual cortex. Results obtained by the two methods
were in close agreement. The claustrum was found to contain a single,
orderly map of the contralateral hemifield and a small part of the
ipsilateral field. High elevations are represented caudally and ventrally,
low elevations rostrally and dorsally. The surface of the claustrum
represents the periphery of the visual field, while the vertical meridian
lies more ventrally, where the visual claustrum abuts the non-visual part
of the nucleus. Visual field lines (isoazimuths or isoelevations) are
represented as planes in the claustrum. The map is unusual in that
isoazimuth planes are strongly curved and nested within each other, with
peripheral ones enclosing those closer to the vertical meridian. This
arrangement permits an expanded representation of the periphery compared
with what is seen in visual cortex. The inputs from areas 17, 18, 19, 21a,
and PMLS (posteromedial lateral suprasylvian area) are convergent, each
projection retinotopically to the entirety of the claustral map.