G. Leuba et K. Saini, CALCIUM-BINDING PROTEINS IMMUNOREACTIVITY IN THE HUMAN SUBCORTICAL AND CORTICAL VISUAL STRUCTURES, Visual neuroscience, 13(6), 1996, pp. 997-1009
The distribution of neurons and fibers immunoreactive (ir) to the thre
e calcium-binding proteins parvalbumin (PV), calbindin D-28k (CB), and
calretinin (CR) was studied in the human lateral geniculate nucleus (
LGN), lateral inferior pulvinar, and optic radiation, and related to t
hat in the visual cortex. In the LGN, PV, CR, and CB immunoreactivity
was present in all laminae, slightly stronger in the magnocellular tha
n in the parvocellular laminae for CB and CR. PV-ir puncta, representi
ng transversally cut axons, and CR-ir fibers were revealed within the
laminae and interlaminar zones, and just beyond the outer border of la
mina 6 in the geniculate capsule. In the optic radiation both PV- and
CR-immunoreactive neurons, puncta, and fibers were present. CB immunor
eactivity was revealed in neurons of all laminae of the lateral genicu
late nucleus, including S lamina and interlaminar zones. There were ha
rdly any CB-ir puncta or fibers in the laminae, interlaminar zones, ge
niculate capsule, or optic radiation. In the lateral inferior pulvinar
, immunoreactive neurons for the three calcium-binding proteins were p
resent in smaller number than in the LGN, as well as PV-ir puncta and
CR-ir fibers within the nucleus and in the pulvinar capsule. In the wh
ite matter underlying area 17, fibers intermingled with a few scattere
d neurons were stained for both PV and CR, but very rarely for CB. The
se fibers stopped at the limit between areas 17 and 18. Area 17 showed
a dense plexus of PV-ir puncta and neurons in the thalamo-receptive l
ayer IV and CR-ir puncta and neurons both in the superficial layers I-
II, IIIC, and in layer VA. Cajal-Retzius CR-ir neurons were present in
layer I. CB-ir puncta were almost confined to layer I-III and CB-ir n
eurons to layer II. Finally the superior colliculus exhibited mostly p
opulations of PV and CR pyramidal-like immunoreactive neurons, mainly
in the intermediate tier. These data suggest that in the visual thalam
us most calcium-binding protein immunoreactive neurons project to the
visual cortex, while in the superior colliculus a smaller immunoreacti
ve population represent projection neurons.