NUCLEUS OF THE THALAMUS AND PULVINAR-LATERALIS POSTERIOR COMPLEX - A WGA-HRP STUDY

The present study utilises the capacity of wheat germ agglutinin-conju gated horseradish peroxidase to label both afferent and efferent proje ctions from selected regions of the thalamic reticular nucleus (TRN) t o the pulvinar lateralis-posterior complex (Pul-LP) of the cat. Fourte en injections into the TRN located between anterior-posterior levels 8 .5 and 4.5 were analysed. The projection of the TRN to the Pul-LP comp lex is roughly organised in a topographic manner and is not widespread within the thalamus. Anterograde labelling in the Pul-LP extended ros trocaudally with a slight oblique dorsoventral orientation. Projection s to the medial LP were predominantly but not exclusively from rostral areas of TRN, while projections to the lateral LP were largely from c audal areas of the TRN. Projections to other areas of the Pul-LP were sparse. The connections between TRN and Pul-LP were reciprocal, althou gh the distribution of labelled cells and anterograde labelling was no t completely overlapping. Reciprocal connections with the dorsal later al geniculate nucleus were largely with the C-laminae and the medial i nterlaminar nucleus. The results are discussed with reference to the c orticothalamic projections and the visuotopy of the Pul-LP. (C) 1995 W iley-Liss, Inc.